WorldWideScience

Sample records for temperature variations recorded

  1. Holocene temperature variations at a high-altitude site in the Eastern Alps: a chironomid record from Schwarzsee ob Sölden, Austria

    Science.gov (United States)

    Ilyashuk, Elena A.; Koinig, Karin A.; Heiri, Oliver; Ilyashuk, Boris P.; Psenner, Roland

    2011-01-01

    Few well-dated, quantitative Holocene temperature reconstructions exist from high-altitude sites in the Central Eastern Alps. Here, we present a chironomid-based quantitative reconstruction of mean July air temperatures (TJuly) throughout the Holocene for a remote high-mountain lake, Schwarzsee ob Sölden, situated above the treeline at 2796 m a.s.l. in the Austrian Alps. Applying a chironomid-temperature inference model developed from lakes of the Alpine region to a high-resolution chironomid record from the lake provides evidence for early Holocene (ca 10000–8600 cal yr BP) TJuly of up to 8.5 °C, i.e. >4 °C above the modern (1977–2006) mean July temperature. The reconstruction reveals the so-called ‘8.2-ka cold event’ centered at ca 8250–8000 cal yr BP with temperatures ca 3 °C below the early-Holocene thermal maximum. Rather warm (ca 6 °C) and productive conditions prevailed during ca 7900–4500 cal yr BP. The chironomid record suggests a climate transition between ca 5200 and 4500 cal yr BP to cooler TJuly. A distinct cooling trend is evident from ca 4500 until ca 2500 cal yr BP. Thereafter, the study site experienced its coldest conditions (around 4 °C or less) throughout the rest of the Holocene, with the exception of the warming trend during the late 20th century. Beside other factors, the Northern Hemisphere summer insolation seems to be the major driving force for the long-term trends in TJuly at high altitudes in the Eastern Alps. Due to the extreme location of the lake and the limited temperature range represented by the applied calibration data set, the chironomid-based temperature reconstruction fails to track phases of the late-Holocene climatic history with TJuly cooler than 4 °C. Further chironomid-based palaeoclimate model and down-core studies are required to address this problem, provide more realistic TJuly estimates from undisturbed high-altitude lakes in the Alps, and extract a reliable regional

  2. Holocene temperature variations at a high-altitude site in the Eastern Alps: a chironomid record from Schwarzsee ob Sölden, Austria.

    Science.gov (United States)

    Ilyashuk, Elena A; Koinig, Karin A; Heiri, Oliver; Ilyashuk, Boris P; Psenner, Roland

    2011-01-01

    Few well-dated, quantitative Holocene temperature reconstructions exist from high-altitude sites in the Central Eastern Alps. Here, we present a chironomid-based quantitative reconstruction of mean July air temperatures (T(July)) throughout the Holocene for a remote high-mountain lake, Schwarzsee ob Sölden, situated above the treeline at 2796 m a.s.l. in the Austrian Alps. Applying a chironomid-temperature inference model developed from lakes of the Alpine region to a high-resolution chironomid record from the lake provides evidence for early Holocene (ca 10000-8600 cal yr BP) T(July) of up to 8.5 °C, i.e. >4 °C above the modern (1977-2006) mean July temperature. The reconstruction reveals the so-called '8.2-ka cold event' centered at ca 8250-8000 cal yr BP with temperatures ca 3 °C below the early-Holocene thermal maximum. Rather warm (ca 6 °C) and productive conditions prevailed during ca 7900-4500 cal yr BP. The chironomid record suggests a climate transition between ca 5200 and 4500 cal yr BP to cooler T(July). A distinct cooling trend is evident from ca 4500 until ca 2500 cal yr BP. Thereafter, the study site experienced its coldest conditions (around 4 °C or less) throughout the rest of the Holocene, with the exception of the warming trend during the late 20th century. Beside other factors, the Northern Hemisphere summer insolation seems to be the major driving force for the long-term trends in T(July) at high altitudes in the Eastern Alps. Due to the extreme location of the lake and the limited temperature range represented by the applied calibration data set, the chironomid-based temperature reconstruction fails to track phases of the late-Holocene climatic history with T(July) cooler than 4 °C. Further chironomid-based palaeoclimate model and down-core studies are required to address this problem, provide more realistic T(July) estimates from undisturbed high-altitude lakes in the Alps, and extract a reliable regional

  3. EOP TDRs (Temperature-Depth-Recordings) Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature-depth-recorders (TDRs) were attached to commercial longline and research Cobb trawl gear to obtain absolute depth and temperature measurement during...

  4. Record temperature streak bears anthropogenic fingerprint

    Science.gov (United States)

    Mann, Michael E.; Miller, Sonya K.; Rahmstorf, Stefan; Steinman, Byron A.; Tingley, Martin

    2017-08-01

    We use a previously developed semiempirical approach to assess the likelihood of the sequence of consecutive record-breaking temperatures in 2014-2016. This approach combines information from historical temperature data and state-of-the-art historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We find that this sequence of record-breaking temperatures had a negligible (at some point since 2000 is estimated as 30-50% given anthropogenic warming and <0.7% in its absence. The likelihood of observing the specific level of record warmth recorded during 2016 is no more than one-in-a-million neglecting anthropogenic warming, but as high as 27%, i.e., a nearly one-in-three chance of occurrence taking anthropogenic warming into account.

  5. Biomarker records of Holocene climate variations in Asian interior

    Science.gov (United States)

    Song, M.; Liu, Z.; Liu, W.; Zhao, C.; Li, S.; He, Y.

    2012-12-01

    Understanding Holocene climate fluctuation may provide clues to projection of future climate change. Lake sediments in the arid central Asia (ACA), as an archive of past climate information, keep attracting considerable interest. We have retrieved several sediment cores from Lake Manas, an endorheic lake in Zunggar desert, Xinjiang Province, China. Biomarker proxies including alkenone Uk'37, %C37:4 and C37 concentration (C37 Conc), and physical proxies including density and magnetic susceptibility (MS) have been analyzed. We have found substantial climatic and environmental changes during the late Holocene. Density, MS and Uk'37 values are high during Medieval Warm Period (MWP) and C37 Conc is very low. During the Little Ice Age, density and MS decrease, Uk'37 values drop to near 0.1, C37 Conc is increased by 2 to 3 magnitude. Thus, warm and dry conditions dominated MWP while cold and wet conditions dominated LIA, a typical "Westerly" pattern which is opposite to the hydrological variation in Asian monsoonal regions. Biomarker records' correlation with solar irradiance (SI), the North Atlantic Oscillation (NAO), the 1000year ACA Moisture Index (ACAM), and the North Hemisphere Temperature (NHT) suggests SI as one of the forcing factor on temperature fluctuation and cold and wet LIA possibly resulting from westerly-jet shift, negative NAO oscillation and the lower evaporation induced by the decrease of temperature. Biomarker records for the whole Holocene will be also presented.

  6. Assessment of broiler surface temperature variation when exposed to different air temperatures

    Directory of Open Access Journals (Sweden)

    GR Nascimento

    2011-12-01

    Full Text Available This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST of 7- to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb® broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 ºC to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05 from the values obtained by the equations. MST values significantly increased (p < 0.05 when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

  7. Variation in the urban vegetation, surface temperature, air temperature nexus.

    Science.gov (United States)

    Shiflett, Sheri A; Liang, Liyin L; Crum, Steven M; Feyisa, Gudina L; Wang, Jun; Jenerette, G Darrel

    2017-02-01

    Our study examines the urban vegetation - air temperature (Ta) - land surface temperature (LST) nexus at micro- and regional-scales to better understand urban climate dynamics and the uncertainty in using satellite-based LST for characterizing Ta. While vegetated cooling has been repeatedly linked to reductions in urban LST, the effects of vegetation on Ta, the quantity often used to characterize urban heat islands and global warming, and on the interactions between LST and Ta are less well characterized. To address this need we quantified summer temporal and spatial variation in Ta through a network of 300 air temperature sensors in three sub-regions of greater Los Angeles, CA, which spans a coastal to desert climate gradient. Additional sensors were placed within the inland sub-region at two heights (0.1m and 2m) within three groundcover types: bare soil, irrigated grass, and underneath citrus canopy. For the entire study region, we acquired new imagery data, which allowed calculation of the normalized difference vegetation index (NDVI) and LST. At the microscale, daytime Ta measured along a vertical gradient, ranged from 6 to 3°C cooler at 0.1 and 2m, underneath tall canopy compared to bare ground respectively. At the regional scale NDVI and LST were negatively correlated (p<0.001). Relationships between diel variation in Ta and daytime LST at the regional scale were progressively weaker moving away from the coast and were generally limited to evening and nighttime hours. Relationships between NDVI and Ta were stronger during nighttime hours, yet effectiveness of mid-day vegetated cooling increased substantially at the most arid region. The effectiveness of vegetated Ta cooling increased during heat waves throughout the region. Our findings suggest an important but complex role of vegetation on LST and Ta and that vegetation may provide a negative feedback to urban climate warming. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Pathfinder Sea Surface Temperature Climate Data Record

    Science.gov (United States)

    Baker-Yeboah, S.; Saha, K.; Zhang, D.; Casey, K. S.

    2016-02-01

    Global sea surface temperature (SST) fields are important in understanding ocean and climate variability. The NOAA National Centers for Environmental Information (NCEI) develops and maintains a high resolution, long-term, climate data record (CDR) of global satellite SST. These SST values are generated at approximately 4 km resolution using Advanced Very High Resolution Radiometer (AVHRR) instruments aboard NOAA polar-orbiting satellites going back to 1981. The Pathfinder SST algorithm is based on the Non-Linear SST algorithm using the modernized NASA SeaWiFS Data Analysis System (SeaDAS). Coefficients for this SST product were generated using regression analyses with co-located in situ and satellite measurements. Previous versions of Pathfinder included level 3 collated (L3C) products. Pathfinder Version 5.3 includes level 2 pre-processed (L2P), level 3 Uncollated (L3C), and L3C products. Notably, the data were processed in the cloud using Amazon Web Services and are made available through all of the modern web visualization and subset services provided by the THREDDS Data Server, the Live Access Server, and the OPeNDAP Hyrax Server.In this version of Pathfinder SST, anomalous hot-spots at land-water boundaries are better identified and the dataset includes updated land masks and sea ice data over the Antarctic ice shelves. All quality levels of SST values are generated, giving the user greater flexibility and the option to apply their own cloud-masking procedures. Additional improvements include consistent cloud tree tests for NOAA-07 and NOAA-19 with respect to the other sensors, improved SSTs in sun glint areas, and netCDF file format improvements to ensure consistency with the latest Group for High Resolution SST (GHRSST) requirements. This quality controlled satellite SST field is a reference environmental data record utilized as a primary resource of SST for numerous regional and global marine efforts.

  9. Damage Localization of an Offshore Platform considering Temperature Variations

    Directory of Open Access Journals (Sweden)

    Shuqing Wang

    2015-01-01

    Full Text Available Modal parameters are sensitive indicators of structural damages. However, these modal parameters are sensitive not only to damage, but also to the environmental variations. Development of vibration based damage detection methodology which is robust to environmental variation is essentially important for the structural safety. The present paper utilizes a recently developed modal strain energy decomposition (MSED method to localize the damage of an offshore structure. A progress of the present paper is to take the temperature variation into consideration and Monte Carlo simulation is introduced to investigate the effect of temperature variation on the robustness of damage localization. Numerical study is conducted on an offshore platform structure considering the temperature variation. Several damage cases, including single and double damage scenarios, are included to investigate the damage localization algorithm. Results indicate that the MSED algorithm is able to detect the damage despite the temperature variations.

  10. Reconciling divergent trends and millennial variations in Holocene temperatures.

    Science.gov (United States)

    Marsicek, Jeremiah; Shuman, Bryan N; Bartlein, Patrick J; Shafer, Sarah L; Brewer, Simon

    2018-01-31

    Cooling during most of the past two millennia has been widely recognized and has been inferred to be the dominant global temperature trend of the past 11,700 years (the Holocene epoch). However, long-term cooling has been difficult to reconcile with global forcing, and climate models consistently simulate long-term warming. The divergence between simulations and reconstructions emerges primarily for northern mid-latitudes, for which pronounced cooling has been inferred from marine and coastal records using multiple approaches. Here we show that temperatures reconstructed from sub-fossil pollen from 642 sites across North America and Europe closely match simulations, and that long-term warming, not cooling, defined the Holocene until around 2,000 years ago. The reconstructions indicate that evidence of long-term cooling was limited to North Atlantic records. Early Holocene temperatures on the continents were more than two degrees Celsius below those of the past two millennia, consistent with the simulated effects of remnant ice sheets in the climate model Community Climate System Model 3 (CCSM3). CCSM3 simulates increases in 'growing degree days'-a measure of the accumulated warmth above five degrees Celsius per year-of more than 300 kelvin days over the Holocene, consistent with inferences from the pollen data. It also simulates a decrease in mean summer temperatures of more than two degrees Celsius, which correlates with reconstructed marine trends and highlights the potential importance of the different subseasonal sensitivities of the records. Despite the differing trends, pollen- and marine-based reconstructions are correlated at millennial-to-centennial scales, probably in response to ice-sheet and meltwater dynamics, and to stochastic dynamics similar to the temperature variations produced by CCSM3. Although our results depend on a single source of palaeoclimatic data (pollen) and a single climate-model simulation, they reinforce the notion that climate

  11. Daytime variations in temperature, dissolved oxygen and ph in ...

    African Journals Online (AJOL)

    Daytime variations in temperature, dissolved oxygen concentration and pH were investigated at 3-hourly intervals from 6a.m. to 6 p.m. January had the lowest temperature values, while at noon; September and January had the lowest air and pond water temperature values respectively.Dissolved oxygen increase from 6a.m.

  12. Holocene paleomagnetic secular variation records from the East China Sea

    Science.gov (United States)

    Zheng, Y.; Zheng, H.; Kissel, C.; Laj, C. E.; Deng, C.

    2011-12-01

    Paleomagnetic study on marine sediments can provide continuous, high-resolution records of short-term fluctuations of the Earth's magnetic field, which can be used for inter-core correlations at regional scale. However, Holocene paleomagnetic secular variation (PSV) records from marine sediment are still rare. Detailed paleomagnetic and rock magnetic studies were conducted on u-channel samples from rapidly deposited sediment core MD06-3040 (27.72°N, 121.78°E; 46 m water depth), on the East China Sea (ECS) inner continental shelf Holocene marine sequence, during IMAGES XIV Marco Polo 2 cruise on the R. V. Marion Dufresne (IPEV). The 19.22 m long core spans the entire Holocene, with theoretical high-resolution of about 20-year for paleomagnetic studies, and paleomagnetic secular variation (PSV) for the last 7500 years was retrieved from the uppermost 15.8 m fine-grained sediments. The dominant carrier of the remanent magnetization is magnetite, with some contributions from iron sulfide, such as greigite below 3.5 m, due to post-depositional diagenesis. The Characteristic Remanent magnetization (ChRM) is well defined by a single magnetization component and Maximum Angular Deviations (MAD) lower than 5°. Therefore, the information of paleomagnetic directions is still preserved after diagenetic alteration. Inclination of core MD06-3040 presents seven relatively high peaks, and declination presents four obvious eastern ward drifts during the last 7500 years. These variations can be well compared to that obtained from lakes in Japan, and some features are also comparable to the records from Europe with temporal offset. The power spectrum analysis shows that the inclination has significant power at the period of ~660 years, and declination at the period of ~3500 years and 1300 years. These periods are similar to that from Japan and North America, in which the period of ~1300 years for declination has been reported in many areas around the world. The observed PSV from

  13. Global increase in record-breaking monthly-mean temperatures

    NARCIS (Netherlands)

    Coumou, Dim; Robinson, Alexander; Rahmstorf, Stefan

    The last decade has produced record-breaking heat waves in many parts of the world. At the same time, it was globally the warmest since sufficient measurements started in the 19th century. Here we show that, worldwide, the number of local record-breaking monthly temperature extremes is now on

  14. Graphical Interface for Measuring and Recording Temperature with the DS18B20 Digital Output Sensor

    OpenAIRE

    Viorel POPA; Elena POPA

    2013-01-01

    The article presents the authors’ two originalgraphical interfaces made in Borland Delphi anddesigned to measure and record (with the DS18B20sensor) a wide range of negative and positivetemperatures. The first interface allows the readingof a sensor’s unique code and then themeasurement and recording of temperature. Thesecond interface can work with a variable numberof such sensors once their unique code has beenentered.The interfaces have been conceived for thestudy of the slow variations of...

  15. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    ckaonga

    City, Malawi for a 29-year period (1985 to 2013) were assessed for the possibility of climate variation. In addition, the concentration of carbon ... Key words: Climate variation, solar radiation, temperature, weather. INTRODUCTION. The world's climate ..... changes and nocturnal global warming. Science 283 (5399):229-231.

  16. Variation between cut chrysanthemum cultivars in response to suboptimal temperature

    NARCIS (Netherlands)

    Ploeg, van der A.; Kularathne, R.J.K.N.; Carvalho, S.M.P.; Heuvelink, E.

    2007-01-01

    To breed for more energy-efficient cut chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars it is important to know the variation of the temperature response existing in modern cultivars. In a greenhouse experiment with 25 chrysanthemum cultivars, a significant variation was observed in

  17. Diurnal variation of tropospheric temperature at a tropical station

    Directory of Open Access Journals (Sweden)

    K. Revathy

    2001-08-01

    Full Text Available The vertical velocity in the troposphere-lower stratosphere region measured using MST radar has been utilized to evaluate the temperature profile in the region. The diurnal variation of the tropospheric temperature on one day in August 1998 at the tropical station Gadanki (13.5° N, 79.2° E has been studied using the MST radar technique. The diurnal variation of the temperature revealed a prominent diurnal variation with the peak in the afternoon hours increasingly delayed in altitude. The tropopause temperature and altitude exhibited a clear diurnal cycle.Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere - composition and chemistry; instruments and technique

  18. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    Climate variation based on temperature and solar radiation data over a 29 year period in Lilongwe City, Malawi. CC Kaonga, IBM Kosamu, C Tenthani. Abstract. Economies that mainly depend on agriculture are to a large extent being negatively impacted by climate change. In this study, temperature and solar radiation data ...

  19. Spatial Variation of Temperature and Precipitation in Bhutan and Links to Vegetation and Land Cover

    Directory of Open Access Journals (Sweden)

    Ugyen Dorji

    2016-02-01

    Full Text Available Bhutan, located in the Himalayas in the South Asian monsoon region, has extremely high variation in elevation, climatic conditions, and land cover despite its small geographical area, as well as great biodiversity. This paper provides the first comprehensive description of climatic conditions in Bhutan. It assesses the spatial variation of temperature and precipitation across the country and evaluates the causes for this variation based on daily data from 70 meteorological stations that have been recording data for time spans ranging from 3 to 21 years. Temperature and precipitation show contrasting spatial variation, with temperature primarily affected by elevation and precipitation by latitude. Models were developed using mixed linear regression models to predict seasonal and annual mean temperature and precipitation based on geographical location. Using linear regression we found that temperatures changed by about 0.5°C for every 100 m of change in elevation, with lapse rates being highest in February, March, and November and lowest from June to August. The lapse rate was highest for minimum temperatures and lowest for maximum temperatures, with the greatest difference during winter. The spatial distribution of precipitation was mainly controlled by latitude, having a quadratic relationship, with the highest rates in the southern foothills of the Himalayan range and the lowest at midlatitudes. The land cover is affected by topography and local climate, with variations in temperature being a main deciding factor for vegetation types; most human settlements and associated land uses are concentrated at lower elevations.

  20. Effect of agrowastes, pH and temperature variation on the growth of ...

    African Journals Online (AJOL)

    The effect of pH and temperature variations on the growth of Volvariella volvacea cultivated on various agricultural wastes singly and in various combinations was studied. A pH range of 5.5 to 8.5 recorded the maximum mycelia yield and the highest mycelia weight was recorded at pH 6.5. The mycelia yield decreased at pH ...

  1. Holocene Temperature Record of the North Antarctic Peninsula

    Science.gov (United States)

    Willmott, V.; Kim, J.; Domack, E. W.; Sinninghe Damsté, J. S.; Schouten, S.

    2009-12-01

    Because sea temperature plays a critical role not only on the stability of ice shelves and sea ice formation, but as well on the marine ecology of polar areas, a lot of effort has been placed to reconstruct the past climate using proxies from ice, marine and terrestrial records. However, it has been difficult to apply traditional paleoenvironmental proxies in polar areas because of problems that include insufficient dating of recovered sequences, complexities introduced by glacial activity (i.e. glacial erosion), sea-ice cover and poor calcium carbonate preservation. Despite these difficulties, some paleoenvironmental records have been obtained so far although paleotemperature records are still very scarce. The TEX86 (TetraEther indeX of lipids with 86 carbon atoms), is an organic-based paleothermomether (Schouten et al., 2002) based on the relative distribution of archaeal lipids (GDGTs) biosynthesized by marine Crenarchaeota, one of the main prokaryotes of today’s oceans. Although the use of TEX86 in polar areas may be promising because it can be measured in carbonate poor sediments, its global correlation with sea surface temperature (SST) (Kim et al., 2008) revealed that the relationship between TEX86 values and SSTs over the entire temperature range was non-linear, mainly because below 5°C, i.e. in the polar oceans, changes in TEX86 were relatively minor with temperature. Recently, we obtained new insights on the relation between isoprenoid GDGTs and SST in polar oceans using an extended core-top sediment dataset which has lead to a new GDGT index which minimizes the scatter at low temperatures. We applied this new index to obtain a detailed Holocene SST record from well dated sediment cores from the north western Antarctic Peninsula. Temperature ranges show absolute temperature estimates (between -1 and 6 °C) in agreement with present day temperature range, reaching warmer temperatures between 6 to 8 ky. Cooler temperatures of about 2 °C dominates the

  2. Robust Optimization of a MEMS Accelerometer Considering Temperature Variations

    Science.gov (United States)

    Liu, Guangjun; Yang, Feng; Bao, Xiaofan; Jiang, Tao

    2015-01-01

    A robust optimization approach for a MEMS accelerometer to minimize the effects of temperature variations is presented. The mathematical model of the accelerometer is built. The effects of temperature variations on the output performance of the accelerometer are determined, and thermal deformation of the accelerometer is analyzed. The deviations of the output capacitance and resonance frequency due to temperature fluctuations are calculated and discussed. The sensitivity analysis method is employed to determine the design variables for robust optimization and find out the key structural parameters that have most significant influence on the output capacitance and resonance frequency of the accelerometer. The mathematical model and procedure for the robust optimization of the accelerometer are proposed. The robust optimization problem is solved and discussed. The robust optimization results show that an optimized accelerometer with high sensitivity, high temperature robustness and decoupling structure is finally obtained. PMID:25785308

  3. Modeling fish community dynamics in Florida Everglades: Role of temperature variation

    Science.gov (United States)

    Al-Rabai'ah, H. A.; Koh, H. L.; DeAngelis, Donald L.; Lee, Hooi-Ling

    2002-01-01

    Temperature variation is an important factor in Everglade wetlands ecology. A temperature fluctuation from 17°C to 32°C recorded in the Everglades may have significant impact on fish dynamics. The short life cycles of some of Everglade fishes has rendered this temperature variation to have even more impacts on the ecosystem. Fish population dynamic models, which do not explicitly consider seasonal oscillations in temperature, may fail to describe the details of such a population. Hence, a model for fish in freshwater marshes of the Florida Everglades that explicitly incorporates seasonal temperature variations is developed. The model's main objective is to assess the temporal pattern of fish population and densities through time subject to temperature variations. Fish population is divided into 2 functional groups (FGs) consisting of small fishes; each group is subdivided into 5-day age classes during their life cycles. Many governing sub-modules are set directly or indirectly to be temperature dependent. Growth, fecundity, prey availability, consumption rates and mortality are examples. Several mortality sub-modules are introduced in the model, of which starvation mortality is set to be proportional to the ratio of prey needed to prey available at that particular time step. As part of the calibration process, the model is run for 50 years to ensure that fish densities do not go to extinction, while the simulation period is about 8 years.

  4. Did European temperatures in 1540 exceed present-day records?

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    Orth, Rene; Vogel, Martha M.; Luterbacher, Jürg; Pfister, Christian; Seneviratne, Sonia I.

    2017-04-01

    There is strong evidence that the year 1540 was exceptionally dry and warm in Central Europe. Here we infer 1540 summer temperatures from the number of dry days (NDDs) in spring (March-May) and summer (June-August) in 1540 derived from historical documentary evidence published elsewhere, and compare our estimates with present-day temperatures. We translate the NDD values into temperature distributions using a linear relationship between modeled temperature and NDD from a 3000 year pre-industrial control simulation with the Community Earth System Model (CESM). Our results show medium confidence that summer mean temperatures (T JJA) and maximum temperatures (TXx) in Central Europe in 1540 were warmer than the respective present-day mean summer temperatures (assessed between 1966-2015). The model-based reconstruction suggests further that with a probability of 40%-70%, the highest daily temperatures in 1540 were even warmer than in 2003, while there is at most a 20% probability that the 1540 mean summer temperature was warmer than that of 2003 in Central Europe. As with other state-of-the-art analyses, the uncertainty of the reconstructed 1540 summer weather in this study is considerable, for instance as extrapolation is required because 1540-like events are not captured by the employed Earth system model (ESM), and neither by other ESMs. However, in addition to paleoclimatological approaches we introduce here an independent methodology to estimate 1540 temperatures, and contribute consequently to a reduced overall uncertainty in the analysis of this event. The characterization of such events and the related climate system functioning is particularly relevant in the context of global warming and the corresponding increase of extreme heat wave magnitude and occurrence frequency. Orth, R., M.M. Vogel, J. Luterbacher, C. Pfister, and S.I. Seneviratne, (2016): Did European temperatures in 1540 exceed present-day records? Env. Res. Lett., 11, 114021, doi: 10.1088/1748-9326/11/11/114021

  5. Analysis of global and hemispheric temperature records and prognosis

    Science.gov (United States)

    Werner, Rolf; Valev, Dimitar; Danov, Dimitar; Guineva, Veneta; Kirillov, Andrey

    2015-06-01

    Climate changes are connected to long term variations of global and hemispheric temperatures, which are important for the work out of socio-political strategy for the near future. In the paper the annual temperature time series are modeled by linear multiple regression to identify important climate forcings including external climate factors such as atmospheric CO2 content, volcanic emissions, and the total solar irradiation as well as internal factors such as El Niño-Southern oscillation, Pacific decadal oscillation and Atlantic multidecadal oscillation. Adjusted temperatures were determined by removal of all significant influences except CO2. The adjusted temperatures follow a linear dependence toward the logarithm of the CO2 content, and the coefficient of determination is about 0.91. The evolution of the adjusted temperatures suggests that the warming due to CO2 from the beginning of the studied here time interval in 1900 has never stopped and is going on up to now. The global warming rate deduced from the adjusted temperatures since 1980 is about 0.14 ± 0.02 °C/decade. The warming rate reported in the IPCC assessment report 4 based on observed global surface temperature set is about 20% higher, due to the warming by the Atlantic multidecadal oscillation additional to the anthropogenic warming. The predicted temperature evolution based on long time changes of CO2 and the Atlantic multidecadal oscillation index shows that the Northern Hemispheric temperatures are modulated by the Atlantic multidecadal oscillation influence and will not change significantly to about 2040, after that they will increase speedily, just like during the last decades of the past century. The temperatures of the Southern Hemisphere will increase almost linearly and don't show significant periodic changes due to Atlantic multidecadal oscillation. The concrete warming rates of course are strongly depending on the future atmospheric CO2 content.

  6. NOTE: Effects of temperature variation on MOSFET dosimetry

    Science.gov (United States)

    Cheung, Tsang; Butson, Martin J.; Yu, Peter K. N.

    2004-07-01

    This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 °C up to 40 °C. Thus standard irradiations performed at room temperature can be directly compared to in vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependent on the dose history of the MOSFET dosimeter. However, the variation can be accounted for in the measurement method. For accurate dosimetry, the detector should be placed for approximately 60 s on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 s after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established.

  7. Normal variation in thermal radiated temperature in cattle: implications for foot-and-mouth disease detection

    Directory of Open Access Journals (Sweden)

    Gloster John

    2011-11-01

    Full Text Available Abstract Background Thermal imagers have been used in a number of disciplines to record animal surface temperatures and as a result detect temperature distributions and abnormalities requiring a particular course of action. Some work, with animals infected with foot-and-mouth disease virus, has suggested that the technique might be used to identify animals in the early stages of disease. In this study, images of 19 healthy cattle have been taken over an extended period to determine hoof and especially coronary band temperatures (a common site for the development of FMD lesions and eye temperatures (as a surrogate for core body temperature and to examine how these vary with time and ambient conditions. Results The results showed that under UK conditions an animal's hoof temperature varied from 10°C to 36°C and was primarily influenced by the ambient temperature and the animal's activity immediately prior to measurement. Eye temperatures were not affected by ambient temperature and are a useful indicator of core body temperature. Conclusions Given the variation in temperature of the hooves of normal animals under various environmental conditions the use of a single threshold hoof temperature will be at best a modest predictive indicator of early FMD, even if ambient temperature is factored into the evaluation.

  8. Estimating trends in the global mean temperature record

    Science.gov (United States)

    Poppick, Andrew; Moyer, Elisabeth J.; Stein, Michael L.

    2017-06-01

    Given uncertainties in physical theory and numerical climate simulations, the historical temperature record is often used as a source of empirical information about climate change. Many historical trend analyses appear to de-emphasize physical and statistical assumptions: examples include regression models that treat time rather than radiative forcing as the relevant covariate, and time series methods that account for internal variability in nonparametric rather than parametric ways. However, given a limited data record and the presence of internal variability, estimating radiatively forced temperature trends in the historical record necessarily requires some assumptions. Ostensibly empirical methods can also involve an inherent conflict in assumptions: they require data records that are short enough for naive trend models to be applicable, but long enough for long-timescale internal variability to be accounted for. In the context of global mean temperatures, empirical methods that appear to de-emphasize assumptions can therefore produce misleading inferences, because the trend over the twentieth century is complex and the scale of temporal correlation is long relative to the length of the data record. We illustrate here how a simple but physically motivated trend model can provide better-fitting and more broadly applicable trend estimates and can allow for a wider array of questions to be addressed. In particular, the model allows one to distinguish, within a single statistical framework, between uncertainties in the shorter-term vs. longer-term response to radiative forcing, with implications not only on historical trends but also on uncertainties in future projections. We also investigate the consequence on inferred uncertainties of the choice of a statistical description of internal variability. While nonparametric methods may seem to avoid making explicit assumptions, we demonstrate how even misspecified parametric statistical methods, if attuned to the

  9. Periodic Interannual Variations of Midwestern United States Temperatures in December.

    Science.gov (United States)

    1982-01-01

    IN DECEMBER BY DOUGLAS CARL PEARSON CAPT USAF A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCINCE ...analyzed and investigated for their predictive capabilities. The strong signal at St. Cloud in central Minnesota (Fig. 2) provides a logical direction for... directions in these sensitive areas. A subtle change of flow pattern can result in a large temperature response in certain sensitive areas. Slight variations

  10. Prenatal exposure to diurnal temperature variation and early childhood pneumonia.

    Science.gov (United States)

    Zeng, Ji; Lu, Chan; Deng, Qihong

    2017-04-01

    Childhood pneumonia is one of the leading single causes of mortality and morbidity in children worldwide, but its etiology still remains unclear. We investigate the association between childhood pneumonia and exposure to diurnal temperature variation (DTV) in different timing windows. We conducted a prospective cohort study of 2,598 children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed by a questionnaire administered by the parents. Individual exposure to DTV during both prenatal and postnatal periods was estimated. Logic regression models was used to examine the association between childhood pneumonia and DTV exposure in terms of odds ratios (OR) and 95% confidence interval (CI). Lifetime prevalence of childhood pneumonia in preschool children in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal DTV exposure, with adjusted OR (95%CI) =1.19 (1.02-1.38), particularly during the second trimester. However, childhood pneumonia not associated with postnatal DTV exposure. Sensitivity analysis indicated that boys are more susceptible to the pneumonia risk of diurnal temperature variation than girls. We further observed that the prevalence of childhood pneumonia was decreased in recent years as DTV shrinked. Early childhood pneumonia was associated with prenatal exposure to the diurnal temperature variation (DTV) during pregnancy, particularly in the second trimester, which suggests fetal origin of childhood pneumonia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Unexpected and Unexplained Surface Temperature Variations on Mimas

    Science.gov (United States)

    Howett, C.; Spencer, J. R.; Pearl, J. C.; Hurford, T. A.; Segura, M.; Cassini Cirs Team

    2010-12-01

    Until recently it was thought one of the most interesting things about Mimas, Saturn’s innermost classical icy moon, was its resemblance to Star Wars’ Death Star. However, a bizarre pattern of daytime surface temperatures was observed on Mimas using data obtained by Cassini’s Composite Infrared Spectrometer (CIRS) in February 2010. The observations were taken during Cassini’s closest ever encounter with Mimas (<10,000 km) and cover the daytime anti-Saturn hemisphere centered on longitude ~145° W. Instead of surface temperatures smoothly increasing throughout the morning and early afternoon, then cooling in the evening, as expected, a sharp V-shaped boundary is observed separating cooler midday and afternoon temperatures (~77 K) on the leading side from warmer morning temperatures (~92 K) on the trailing side. The boundary’s apex is centered at equatorial latitudes near the anti-Saturn point and extends to low north and south latitudes on the trailing side. Subtle differences in the surface colors have been observed that are roughly spatially correlated with the observed extent of the temperature anomaly, with the cooler regions tending to be bluer (Schenk et al., Submitted). However, visible-wavelength albedo is similar in the two regions, so albedo variations are probably not directly responsible for the thermal anomaly. It is more likely that thermal inertia variations produce the anomaly, with thermal inertia being unusually high in the region with anomalously low daytime temperatures. Comparison of the February 2010 CIRS data to previous lower spatial resolution data taken at different local times tentatively confirm that the cooler regions do indeed display higher thermal inertias. Bombardment of the surface by high energy electrons from Saturn’s radiation belts has been proposed to explain the observed color variations (Schenk et al., Submitted). Electrons above ~1 MeV preferentially impact Mimas’ leading hemisphere at low latitudes where they

  12. Performance Variation of Ferrite Magnet PMBLDC Motor with Temperature

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Mijatovic, Nenad; Jensen, Bogi Bech

    2015-01-01

    The price fluctuations of rare earth metals and the uncertainty in their availability has generated an increased interest in ferrite magnet machines. The influence of temperature on BH characteristics of the ferrite magnet differ considerably from that of the rare earth magnet and hence, requires...... a different approach when deciding their operating point. In this work, laboratory measured BH curves of a ferrite magnet are used for estimating the possibility of demagnetization in a segmented axial torus (SAT) permanent magnet brushless DC (PMBLDC) motor. The BH characteristics for different temperatures...... have been used to study the performance variation of the ferrite magnet SAT PMBLDC motor with temperature. A detailed analysis is carried out to ensure that, the designed ferrite magnet motor is capable of delivering the specified torque throughout the operating speed, without any irreversible...

  13. Decadal climate variation recorded in modern global carbonate archives (brachiopods, molluscs)

    Science.gov (United States)

    Romanin, Marco; Zaki, Amir H.; Davis, Alyssa; Shaver, Kristen; Wang, Lisha; Aleksandra Bitner, Maria; Capraro, Luca; Preto, Nereo; Brand, Uwe

    2017-04-01

    The progress of the Earth's warming trend has rapidly accelerated in the last few decades due to the increase in emission of anthropogenic greenhouse gases. The exchange of heat between the atmosphere and seawater has consequently elevated the rate of temperature buildup in the low and high latitude ocean. Records of the variation in seawater temperature in response to local and global changes in climate are preserved within the carbonate structures of marine biogenic archives. Investigating the isotopic composition of the archives' growth increments documents the magnitude of sea surface temperature (SST) change. A long-term (1956-2012) record of temperature change in sub-tropical seawater was acquired from the giant clam Tridacna maxima collected from the Red Sea in conjunction with published results of the oyster Hyotissa hyotis (Titschack et al., 2010). Variation in polar-subpolar SST was obtained from the brachiopod Magellania venosa recovered from the coastal area of southern Chile, and from the proxy record of Hemithiris psittacea of Hudson Bay (Brand et al., 2014). The former reveals a long-term (1961-2012) time-series of Antarctic-induced oceanographic change in the southern hemisphere, while the latter represents a trend of Hudson Bay seawater SST in the northern hemisphere. Evaluation of the isotopic compositions confirms the equilibrium incorporation of oxygen isotopes with respect to ambient seawater in brachiopods and some bivalves. A general trend of decreasing δ18O values in the Red Sea molluscs is observed, indicating an increase in tropical seawater temperature of about 0.79°C since 1988. The δ18O values of the polar-subpolar brachiopods display similar depletion slopes but of larger magnitudes than that of the Red Sea archives. This signifies a rise in seawater temperature of about 1.47°C in Hudson Bay since 1991, and about 2.08°C in southern Chile since 1988. The 2013 IPCC report suggests an increase in SST of +0.094°C per decade (average

  14. Small velocity and finite temperature variations in kinetic relaxation models

    KAUST Repository

    Markowich, Peter

    2010-01-01

    A small Knuden number analysis of a kinetic equation in the diffusive scaling is performed. The collision kernel is of BGK type with a general local Gibbs state. Assuming that the flow velocity is of the order of the Knudsen number, a Hilbert expansion yields a macroscopic model with finite temperature variations, whose complexity lies in between the hydrodynamic and the energy-transport equations. Its mathematical structure is explored and macroscopic models for specific examples of the global Gibbs state are presented. © American Institute of Mathematical Sciences.

  15. Temperature Dependent Variations of Phonon Interactions in Nanocrystalline Cerium Oxide

    Directory of Open Access Journals (Sweden)

    Sugandha Dogra Pandey

    2015-01-01

    Full Text Available The temperature dependent anharmonic behavior of the phonon modes of nanocrystalline CeO2 was investigated in the temperature range of 80–440 K. The anharmonic constants have been derived from the shift in phonon modes fitted to account for the anharmonic contributions as well as the thermal expansion contribution using the high pressure parameters derived from our own high pressure experimental data reported previously. The total anharmonicity has also been estimated from the true anharmonicity as well as quasiharmonic component. In the line-width variation analysis, the cubic anharmonic term was found to dominate the quartic term. Finally, the phonon lifetime also reflected the trend so observed.

  16. Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

    Science.gov (United States)

    Valle-Guadarrama, Salvador; Espinosa-Solares, Teodoro; López-Cruz, Irineo L; Domaschko, Max

    2011-05-01

    A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.

  17. Semiannual Variation in the Number of Energetic Electron Precipitation Events Recorded in the Polar Atmosphere

    Science.gov (United States)

    Stozhkov, Y. Ivanovich; Makhmutov, V. S.; Bazilevskaya, G. A.; Krainev, M. B.; Svirkhevskaya, A. K.; Svirzhevsky, N. S.; Mailin, S. Y.

    2003-07-01

    The analysis of the monthly numbers of Electron Precipitation Events (EPEs) recorded at Olenya station (Murmansk region) during 1970-1987, shows the semiannual variation with two maxima centered on April and September. We analyse the interplanetary plasma and geomagnetic indices data sets associated with the EPEs recorded. The possible relationship of this variation and RusselMcPherron, Equino ctial and Axial effects is discussed.

  18. Multicomponent, multiphase flow in porous media with temperature variation

    Energy Technology Data Exchange (ETDEWEB)

    Wingard, J.S.; Orr, F.M. Jr.

    1990-10-01

    Recovery of hydrocarbons from porous media is an ongoing concern. Advanced techniques augment conventional recovery methods by injecting fluids that favorably interact with the oil. These fluids interact with the oil by energy transfer, in the case of steam injection, or by mass transfer, as in a miscible gas flood. Often both thermal and compositional considerations are important. An understanding of these injection methods requires knowledge of how temperature variations, phase equilibrium and multiphase flow in porous media interact. The material balance for each component and energy balance are cast as a system of non-strictly hyperbolic partial differential equations. This system of equations is solved using the method of characteristics. The model takes into account the phase behavior by using the Peng-Robinson equation of state to partition the individual components into different phases. Temperature effects are accounted for by the energy balance. Flow effects are modelled by using fractional flow curves and a Stone's three phase relative permeability model. Three problems are discussed. The first problem eliminates the phase behavior aspect of the problem by studying the flow of a single component as it undergoes an isothermal phase change. The second couples the effects of temperature and flow behavior by including a second component that is immiscible with the original component. Phase behavior is added by using a set of three partially miscible components that partition into two or three separate phases. 66 refs., 54 figs., 14 tabs.

  19. Assessing recent warming using instrumentally homogeneous sea surface temperature records.

    Science.gov (United States)

    Hausfather, Zeke; Cowtan, Kevin; Clarke, David C; Jacobs, Peter; Richardson, Mark; Rohde, Robert

    2017-01-01

    Sea surface temperature (SST) records are subject to potential biases due to changing instrumentation and measurement practices. Significant differences exist between commonly used composite SST reconstructions from the National Oceanic and Atmospheric Administration's Extended Reconstruction Sea Surface Temperature (ERSST), the Hadley Centre SST data set (HadSST3), and the Japanese Meteorological Agency's Centennial Observation-Based Estimates of SSTs (COBE-SST) from 2003 to the present. The update from ERSST version 3b to version 4 resulted in an increase in the operational SST trend estimate during the last 19 years from 0.07° to 0.12°C per decade, indicating a higher rate of warming in recent years. We show that ERSST version 4 trends generally agree with largely independent, near-global, and instrumentally homogeneous SST measurements from floating buoys, Argo floats, and radiometer-based satellite measurements that have been developed and deployed during the past two decades. We find a large cooling bias in ERSST version 3b and smaller but significant cooling biases in HadSST3 and COBE-SST from 2003 to the present, with respect to most series examined. These results suggest that reported rates of SST warming in recent years have been underestimated in these three data sets.

  20. Analysis of Long-Term Temperature Variations in the Human Body.

    Science.gov (United States)

    Dakappa, Pradeepa Hoskeri; Mahabala, Chakrapani

    2015-01-01

    Body temperature is a continuous physiological variable. In normal healthy adults, oral temperature is estimated to vary between 36.1°C and 37.2°C. Fever is a complex host response to many external and internal agents and is a potential contributor to many clinical conditions. Despite being one of the foremost vital signs, temperature and its analysis and variations during many pathological conditions has yet to be examined in detail using mathematical techniques. Classical fever patterns based on recordings obtained every 8-12 h have been developed. However, such patterns do not provide meaningful information in diagnosing diseases. Because fever is a host response, it is likely that there could be a unique response to specific etiologies. Continuous long-term temperature monitoring and pattern analysis using specific analytical methods developed in engineering and physics could aid in revealing unique fever responses of hosts and in different clinical conditions. Furthermore, such analysis can potentially be used as a novel diagnostic tool and to study the effect of pharmaceutical agents and other therapeutic protocols. Thus, the goal of our article is to present a comprehensive review of the recent relevant literature and analyze the current state of research regarding temperature variations in the human body.

  1. A new high-resolution record of Holocene geomagnetic secular variation from New Zealand

    Science.gov (United States)

    Turner, G. M.; Howarth, J. D.; de Gelder, G. I. N. O.; Fitzsimons, S. J.

    2015-11-01

    We present the first full Holocene palaeomagnetic secular variation record from New Zealand. The 11 500 year-long record, from the sediments of Mavora Lakes, comprises composite declination, inclination and relative palaeointensity logs, compiled from two six-metre long cores and the uppermost 1.5 m of another. An age model has been developed from 28 AMS radiocarbon age determinations on fragments of southern beech (Lophozonia menziesii and Fuscospora cliffortioides) leaves. The excellent between-core correlation in all three components of the field results in a high-resolution palaeosecular variation record, with precise and accurate age control. The variations change in character from high amplitude in-phase declination and inclination swings in the earliest part of the record to low amplitude variations in the middle part and declination and inclination swings that are 90° out of phase, leading to broad looping of the vector in the upper part of the record, that is consistent with westward drifting sources in the outer core. The present-day field at the site (Dec = 24.2°E, Inc = - 70.7 °, F = 59 μT) represents a rare steep and easterly extreme direction, but close to average intensity. The palaeointensity is inferred to have varied between about 40 and 90 μT, with variations that, to some extent, mirror variations in the virtual axial geomagnetic dipole moment seen from global data, but also show some notable differences, particularly in the past few thousand years.

  2. Influence of air temperature variations on incidence of epistaxis.

    Science.gov (United States)

    Comelli, Ivan; Vincenti, Vincenzo; Benatti, Mario; Macri, Gian Franco; Comelli, Denis; Lippi, Giuseppe; Cervellin, Gianfranco

    2015-01-01

    Epistaxis is the most common ear, nose, and throat emergency observed in the emergency department (ED). An increased frequency of this condition has been observed during cooler months, but the results of available studies are controversial. The aim of this study was to investigate the seasonality and association of epistaxis presentations to a large urban ED with variations of air temperature and humidity. This study was a retrospective case series. Information on all the patients who presented for epistaxis in the ED of the Academic Hospital of Parma during the years 2003-2012 and ages ≥ 14 years were retrieved from the hospital data base, excluding those attributable to trauma. The chronologic data of all visits were associated with climate data (air temperature and humidity) by univariate linear regression analysis. Among the 819,596 ED patients seen throughout the observational period, 5404 were admitted for epistaxis. Of these, 5220 were discharged from the ED, whereas 184 (3.4%) needed hospital admission. A strong seasonality of epistaxis was observed, with a peak during winter. A strong negative correlation was also found between the daily number of epistaxes and the mean daily temperature in the whole population as well as in patient subgroups (those undergoing anticoagulant or antiplatelet therapy, or those with hypertension, inherited bleeding disorders, liver cirrhosis, or advanced malignancy). A weaker correlation was also found between air humidity and epistaxis but only in certain subgroups. The results of this study provided a contribution to improve our understanding of the epidemiology of epistaxis and for specific health policies that should also be planned by considering the seasonality of nosebleed.

  3. Diurnal variations of short-term variation and the impact of multiple recordings on measurement accuracy.

    Science.gov (United States)

    Seliger, G; Petroff, D; Seeger, S; Hoyer, D; Tchirikov, M; Schneider, U

    2017-03-01

    Short-term variation (STV) from computerized cardiotocogram heart rate analysis is a parameter that complements decision making, regarding the delivery of fetuses in several high-risk situations. Although studies on the effects of gestational age and fetal pathology are convincing, there is a lack of data exploring diurnal variation and the adequacy of a single measurement. In this prospective observational study, fetal STV was monitored with the AN24 fetal ECG monitor (Monica Healthcare) each hour for at least 10 h in total, beginning at different times. This resulted in data covering all 24 h of the day. Seventy fetuses, low risk with respect to conditions accessible to heart rate monitoring (median 37th week of gestation) were monitored for an average of 12 h. Results of STV per hour were categorized as 'compromised' (STV<4 ms) or 'healthy', (STV⩾4 ms) to calculate the model of predictability. The model proposed (STV of 'healthy' fetuses: 9.6±2.6 ms, 'compromised' fetuses 3.0±0.5 ms, prevalence 1%) leads to a positive predictive value of 39%, which increased to 68 or 80% given two or three pathological (STV<4 ms) measurements, respectively. Diurnal variation was not observed. Single pathological STV values should be corroborated by further measurements in a 24-h interval in otherwise low-risk fetuses before inducing delivery. This may help to avoid unnecessary early births and give the fetus valuable days for intrauterine maturity.

  4. Temporal and spatial variation in temperature experienced by macrofauna at Main Endeavour hydrothermal vent field

    Science.gov (United States)

    Lee, Raymond W.; Robert, Katleen; Matabos, Marjolaine; Bates, Amanda E.; Juniper, S. Kim

    2015-12-01

    A significant focus of hydrothermal vent ecological studies has been to understand how species cope with various stressors through physiological tolerance and biochemical resistance. Yet, the environmental conditions experienced by vent species have not been well characterized. This objective requires continuous observations over time intervals that can capture environmental variability at scales that are relevant to animals. We used autonomous temperature logger arrays (four roughly parallel linear arrays of 12 loggers spaced every 10-12 cm) to study spatial and temporal variations in the thermal regime experienced by hydrothermal vent macrofauna at a diffuse flow vent. Hourly temperatures were recorded over eight months from 2010 to 2011 at Grotto vent in the Main Endeavour vent field on the Juan de Fuca Ridge, a focus area of the Ocean Networks Canada cabled observatory. The conspicuous animal assemblages in video footage contained Ridgeia piscesae tubeworms, gastropods (primarily Lepetodrilus fucensis), and polychaetes (polynoid scaleworms and the palm worm Paralvinella palmiformis). Two dimensional spatial gradients in temperature were generally stable over the deployment period. The average temperature recorded by all arrays, and in some individual loggers, revealed distinctive fluctuations in temperature that often corresponded with the tidal cycle. We postulate that this may be related to changes in bottom currents or fluctuations in vent discharge. A marked transient temperature increase lasting over a period of days was observed in April 2011. While the distributions and behavior of Juan de Fuca Ridge vent invertebrates may be partially constrained by environmental temperature and temperature tolerance, except for the one transient high-temperature event, observed fluid temperatures were generally similar to the thermal preferences for some species, and typically well below lethal temperatures for all species. Average temperatures of the four arrays

  5. Reconstructing last 2000 years of temperature variation from Pyrenean caves (N Spain)

    Science.gov (United States)

    Moreno, Ana; Bartolomé, Miguel; Pérez, Carlos; Sancho, Carlos; Cacho, Isabel; Stoll, Heather; Delgado-Huertas, Antonio; Edwards, R. Lawrence; Cheng, Hai

    2016-04-01

    The Central Pyrenees, and particularly the protected area known as Ordesa and Monte Perdido National Park, is a high-altitude karstic region rich in cavities with active drips and present precipitation of carbonates. Although not generally very abundant, there are speleothems growths in several of those cavities. We present here (1) a three-year seasonal monitoring survey to isolate the environmental parameters influencing isotopic composition of farmed carbonate and (2) the last 2000 years isotopic record resulting from compiling seven stalagmites from three different caves. In temperate regions such as the NE Iberian Peninsula is difficult to discern the influences on δ18O variation in speleothems since temperature, amount of precipitation or even source effect are usually acting simultaneously. Main results after three years monitoring period indicate a strong dependence on air temperature through its influence on rainfall δ18O, although a small amount effect is not discarded. The good overlapping during the observational period of δ18O from actively growing modern stalagmites and air temperature in the area supports this dependence and provides a reliable proxy for the temperature evolution along last millennia. The stalagmites belong to three different caves (Seso, Gloces and B-1 caves) but still present a very coherent isotopic signal allowing us to discard local effects (diagenetic imprint, non-equilibrium fractionation) and to produce a stacked record with decadal resolution. Interpreting this signal as regional temperature variation divides the temporal sequence in five main periods, in consonance with historical stages. Thus, a continuous decrease in temperature characterized the end of the Roman period (0-500 AD). Lower temperatures are dominant during "Dark Ages" (500-1000 AD) that increase during the Medieval Climate Anomaly (MCA, 1000-1400 AD). Following this warm period, the cold signal during the Little Ice Age is very well replicated in several

  6. Modeling seasonal surface temperature variations in secondary tropical dry forests

    Science.gov (United States)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  7. Psychophysics of a nociceptive test in the mouse: ambient temperature as a key factor for variation.

    Directory of Open Access Journals (Sweden)

    Ivanne Pincedé

    Full Text Available BACKGROUND: The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. METHODOLOGY/PRINCIPAL FINDINGS: Basically, the procedures involved heating of the tail with a CO(2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. CONCLUSIONS/SIGNIFICANCE: We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as "pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of

  8. Summer temperatures in the Canadian Rockies during the last millennium: a revised record

    Energy Technology Data Exchange (ETDEWEB)

    Luckman, B.H. [University of Western Ontario, Department of Geography, London, Ontario (Canada); Wilson, R.J.S. [Edinburgh University, School of GeoSciences, Grant Institute, Edinburgh (United Kingdom)

    2005-02-01

    We present a significant update to a millennial summer temperature reconstruction (1073-1983) that was originally published in 1997. Utilising new tree-ring data (predominantly Picea engelmannii), the reconstruction is not only better replicated, but has been extended (950-1994) and is now more regionally representative. Calibration and verification statistics were improved, with the new model explaining 53% of May-August maximum temperature variation compared to the original (39% of April-August mean temperatures). The maximum latewood density data, which are weighted more strongly in the regression model than ringwidth, were processed using regional curve standardisation to capture potential centennial to millennial scale variability. The reconstruction shows warm intervals, comparable to twentieth century values, for the first half of the eleventh century, the late 1300s and early 1400s. The bulk of the record, however, is below the 1901-1980 normals, with prolonged cool periods from 1200 to 1350 and from 1450 to the late 19th century. The most extreme cool period is observed to be in the 1690s. These reconstructed cool periods compare well with known regional records of glacier advances between 1150 and the 1300s, possibly in the early 1500s, early 1700s and 1800s. Evidence is also presented of the influence of solar activity and volcanic events on summer temperature in the Canadian Rockies over the last 1,000 years. Although this reconstruction is regional in scope, it compares well at multi-decadal to centennial scales with Northern Hemisphere temperature proxies and at millennial scales with reconstructions that were also processed to capture longer timescale variability. This coherence suggests that this series is globally important for the assessment of natural temperature variability over the last 1,000 years. (orig.)

  9. Pressure variation of melting temperatures of alkali halides

    Science.gov (United States)

    Arafin, Sayyadul; Singh, Ram N.

    2017-02-01

    The melting temperatures of alkali halides (LiCl, LiF, NaBr, NaCl, NaF, NaI, KBr, KCl, KF, KI, RbBr, RbCl, RbI and CsI) have been evaluated over a wide range of pressures. The solid-liquid transition of alkali halides is of considerable significance due to their huge industrial applications. Our formalism requires a priori knowledge of the bulk modulus and the Grüneisen parameter at ambient conditions to compute Tm at high pressures. The computed values are in very good agreement with the available experimental results. The formalism can satisfactorily be used to compute Tm at high pressures where the experimental data are scanty. Most of the melting curves (Tm versus P) exhibit nonlinear variation with increasing pressure having curvatures downward and exhibit a maximum in some cases like NaCl, RbBr, RbCl and RbI. The values of Tmmax and Pmax corresponding to the maxima of the curves are given.

  10. Evaluation of topographical variation in ocular surface temperature by functional infrared thermography

    Science.gov (United States)

    Tan, Jen Hong; Ng, E. Y. K.; Acharya, U. Rajendra

    2011-11-01

    The objective of this work is to evaluate topographical variation in the ocular surface temperature (OST) among the young, elderly and the subjects wearing contact lens using thermographic methodology. We recorded thermographic sequence lasting of 25 s for each eye. The ocular region in each of the thermal images in the sequence was identified and warped into a standard form. Then, the warped sequence was divided into a number of sub-sequences. A differential image which is an image matrix was obtained from each of these sub-sequences, by subtracting thermal images within the sub-sequence. And the histogram of the differential image was modelled by Gaussian mixture model to discriminate eyelashes from the ocular surface for every thermal image in the sub-sequence. Later, thermal data of eyelashes were eliminated in every thermal image and statistical analysis was performed on the sequences. Finally, topographical profile of each subject group was approximated by equations and illustrated using various temperature profiles. The ocular surface of the young subject was observed to be the warmest, and tear film was determined to play a major role in the topographical and temporal variations in OST. Significant topographical variation was observed among subject groups. Based on our compiled average OST profile (AOSTP), the maximum predictability of the bioheat simulation on ocular model can reach up to 90%.

  11. Assessing diel variation of CH4 flux from rice paddies through temperature patterns

    Science.gov (United States)

    Centeno, Caesar Arloo R.; Alberto, Ma Carmelita R.; Wassmann, Reiner; Sander, Bjoern Ole

    2017-10-01

    The diel variation in methane (CH4) flux from irrigated rice was characterized during the dry and wet cropping seasons in 2013 and 2014 using the eddy covariance (EC) technique. The EC technique has the advantage of obtaining measurements of fluxes at an extremely high temporal resolution (10Hz), meaning it records 36,000 measurements per hour. The EC measurements can very well capture the temporal variations of the diel (both diurnal and nocturnal) fluxes of CH4 and the environmental factors (temperature, surface energy flux, and gross ecosystem photosynthesis) at 30-min intervals. The information generated by this technique is important to enhance our mechanistic understanding of the different factors affecting the landscape scale diel CH4 flux. Distinct diel patterns of CH4 flux were observed when the data were partitioned into different cropping periods (pre-planting, growth, and fallow). The temporal variations of the diel CH4 flux during the dry seasons were more pronounced than during the wet seasons because the latter had so much climatic disturbance from heavy monsoon rains and occasional typhoons. Pearson correlation analysis and Granger causality test were used to confirm if the environmental factors evaluated were not only correlated with but also Granger-causing the diel CH4 flux. Soil temperature at 2.5 cm depth (Ts 2.5 cm) can be used as simple proxy for predicting diel variations of CH4 fluxes in rice paddies using simple linear regression during both the dry and wet seasons. This simple site-specific temperature response function can be used for gap-filling CH4 flux data for improving the estimates of CH4 source strength from irrigated rice production.

  12. Oxygen isotopes in tree rings record variation in precipitation δ(18)O and amount effects in the south of Mexico.

    Science.gov (United States)

    Brienen, Roel J W; Hietz, Peter; Wanek, Wolfgang; Gloor, Manuel

    2013-12-01

    [1] Natural archives of oxygen isotopes in precipitation may be used to study changes in the hydrological cycle in the tropics, but their interpretation is not straightforward. We studied to which degree tree rings of Mimosa acantholoba from southern Mexico record variation in isotopic composition of precipitation and which climatic processes influence oxygen isotopes in tree rings (δ(18)Otr). Interannual variation in δ(18)Otr was highly synchronized between trees and closely related to isotopic composition of rain measured at San Salvador, 710 km to the southwest. Correlations with δ(13)C, growth, or local climate variables (temperature, cloud cover, vapor pressure deficit (VPD)) were relatively low, indicating weak plant physiological influences. Interannual variation in δ(18)Otr correlated negatively with local rainfall amount and intensity. Correlations with the amount of precipitation extended along a 1000 km long stretch of the Pacific Central American coast, probably as a result of organized storm systems uniformly affecting rainfall in the region and its isotope signal; episodic heavy precipitation events, of which some are related to cyclones, deposit strongly (18)O-depleted rain in the region and seem to have affected the δ(18)Otr signal. Large-scale controls on the isotope signature include variation in sea surface temperatures of tropical north Atlantic and Pacific Ocean. In conclusion, we show that δ(18)Otr of M. acantholoba can be used as a proxy for source water δ(18)O and that interannual variation in δ(18)Oprec is caused by a regional amount effect. This contrasts with δ(18)O signatures at continental sites where cumulative rainout processes dominate and thus provide a proxy for precipitation integrated over a much larger scale. Our results confirm that processes influencing climate-isotope relations differ between sites located, e.g., in the western Amazon versus coastal Mexico, and that tree ring isotope records can help in

  13. Daily temperature variation and extreme high temperatures drive performance and biotic interactions in a warming world.

    Science.gov (United States)

    Stoks, Robby; Verheyen, Julie; Van Dievel, Marie; Tüzün, Nedim

    2017-10-01

    We review the major patterns on the effects of daily temperature variation (DTV) and extreme high temperatures (EXT) on performance traits and the resulting outcome of biotic interactions in insects. EXT profoundly affects the outcome of all types of biotic interactions: competitive, predator-prey, herbivore-plant, host-pathogen/parasitoid and symbiotic interactions. Studies investigating effects of DTV on biotic interactions are few but also show strong effects on competitive and host-pathogen/parasitoid interactions. EXT typically reduces predation, and is expected to reduce parasitoid success. The effects of EXT and DTV on the outcome of the other interaction types are highly variable, yet can be predicted based on comparisons of the TPCs of the interacting species, and challenges the formulation of general predictions about the change in biotic interactions in a warming world. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. A comprehensive investigation into the effect of temperature variation on the mechanical properties of sustainable concrete

    Directory of Open Access Journals (Sweden)

    El Mir Abdulkader

    2017-01-01

    Full Text Available Minimizing the production energy and resources consumption are the key principle for engineering sustainability. In the case of concrete structures, this concept can be achieved by the use of materials in the most efficient way considering in the mix design the optimal mechanical and durability properties. The substitution of ordinary Portland cement for other supplementary cementitious materials is assessing the possibility of enhancing the sustainability and decreasing the environmental impact of concrete. Mass concrete is rich in cementitious materials which results in high temperature within the concrete, hence several hazards such as cracking or temperature differences between the interior and the surface of concrete could be prevented. An experimental study evaluated on several one cubic meter sized concrete elements in which during the primary phase of hydration, the temperature variation is recorded in several location offsets with respect to time. Thermal variations results are analyzed in accordance with the cement type, CO2 emission production of cement, compressive strength, water tightness, drying shrinkage and rapid chloride migration coefficient. The results indicate that slag cement CEM III/B 32.5, that incorporates highest amount of slag, ensured improved mechanical, thermal and durability properties in comparison with ordinary Portland cement CEM I 32.5.

  15. Temperature-dependent phenotypic variation of Campylobacter jejuni lipooligosaccharides

    LENUS (Irish Health Repository)

    Semchenko, Evgeny A

    2010-11-30

    Abstract Background Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS) plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry. Results Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37°C and 42°C, respectively, as determined on sodium dodecyl sulphate-polyacrylamide electrophoresis gels with carbohydrate-specific silver staining and blotting with anti-ganglioside ligands, and confirmed by nuclear magnetic resonance (NMR) spectroscopy. The C. jejuni NCTC 11168 original isolate (11168-O) was compared to its genome-sequenced variant (11168-GS), and both were found to have a lower-Mr LOS form, which was different in size and structure to the previously characterized higher-Mr form bearing GM1 mimicry. The lower-Mr form production was found to be dependent on the growth temperature as the production of this form increased from ~5%, observed at 37°C to ~35% at 42°C. The structure of the lower-Mr form contained a β-D-Gal-(1→3)-β-D-GalNAc disaccharide moiety which is consistent with the termini of the GM1, asialo-GM1, GD1, GT1 and GQ1 gangliosides, however, it did not display GM1 mimicry as assessed in blotting studies but was shown in NMR to resemble asialo-GM1. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested of NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested. Conclusion The presence of differing amounts of LOS forms at 37 and 42°C, and the variety of forms observed in different strains, indicate that LOS form variation may play a role in an adaptive mechanism or a stress response of the bacterium during the colonization of different hosts.

  16. Temperature-dependent phenotypic variation of Campylobacter jejuni lipooligosaccharides.

    Science.gov (United States)

    Semchenko, Evgeny A; Day, Christopher J; Wilson, Jennifer C; Grice, I Darren; Moran, Anthony P; Korolik, Victoria

    2010-11-30

    Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS) plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry. Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37 °C and 42 °C, respectively, as determined on sodium dodecyl sulphate-polyacrylamide electrophoresis gels with carbohydrate-specific silver staining and blotting with anti-ganglioside ligands, and confirmed by nuclear magnetic resonance (NMR) spectroscopy. The C. jejuni NCTC 11168 original isolate (11168-O) was compared to its genome-sequenced variant (11168-GS), and both were found to have a lower-M(r) LOS form, which was different in size and structure to the previously characterized higher-M(r) form bearing GM₁ mimicry. The lower-M(r) form production was found to be dependent on the growth temperature as the production of this form increased from ~5%, observed at 37 °C to ~35% at 42 °C. The structure of the lower-M(r) form contained a β-D-Gal-(1→3)-β-D-GalNAc disaccharide moiety which is consistent with the termini of the GM₁, asialo-GM₁, GD₁, GT₁ and GQ₁ gangliosides, however, it did not display GM₁ mimicry as assessed in blotting studies but was shown in NMR to resemble asialo-GM₁. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested of NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested. The presence of differing amounts of LOS forms at 37 and 42 °C, and the variety of forms observed in different strains, indicate that LOS form variation may play a role in an adaptive mechanism or a stress response of the bacterium during the colonization of different hosts.

  17. Temperature-dependent phenotypic variation of Campylobacter jejuni lipooligosaccharides

    Directory of Open Access Journals (Sweden)

    Moran Anthony P

    2010-11-01

    Full Text Available Abstract Background Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry. Results Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37°C and 42°C, respectively, as determined on sodium dodecyl sulphate-polyacrylamide electrophoresis gels with carbohydrate-specific silver staining and blotting with anti-ganglioside ligands, and confirmed by nuclear magnetic resonance (NMR spectroscopy. The C. jejuni NCTC 11168 original isolate (11168-O was compared to its genome-sequenced variant (11168-GS, and both were found to have a lower-Mr LOS form, which was different in size and structure to the previously characterized higher-Mr form bearing GM1 mimicry. The lower-Mr form production was found to be dependent on the growth temperature as the production of this form increased from ~5%, observed at 37°C to ~35% at 42°C. The structure of the lower-Mr form contained a β-D-Gal-(1→3-β-D-GalNAc disaccharide moiety which is consistent with the termini of the GM1, asialo-GM1, GD1, GT1 and GQ1 gangliosides, however, it did not display GM1 mimicry as assessed in blotting studies but was shown in NMR to resemble asialo-GM1. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested of NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested. Conclusion The presence of differing amounts of LOS forms at 37 and 42°C, and the variety of forms observed in different strains, indicate that LOS form variation may play a role in an adaptive mechanism or a stress response of the bacterium during the colonization of different hosts.

  18. Estimation of the location parameter of distributions with known coefficient of variation by record values

    Directory of Open Access Journals (Sweden)

    N. K. Sajeevkumar

    2014-09-01

    Full Text Available In this article, we derived the Best Linear Unbiased Estimator (BLUE of the location parameter of certain distributions with known coefficient of variation by record values. Efficiency comparisons are also made on the proposed estimator with some of the usual estimators. Finally we give a real life data to explain the utility of results developed in this article.

  19. High resolution Holocene paleomagnetic secular variation records from Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Usapkar, A.; Dewangan, P.; Badesab, F.K.; Mazumdar, A.; Ramprasad, T.; Krishna, K.S.; Basavaiah, N.

    We present high resolution paleosecular variation (PSV) records up to 8 cal. kyr BP from three piston cores, MD161/8, MD161/11 and MD161/13 acquired in the Krishna-Godavari (KG) basin, Bay of Bengal. During the Holocene period, high sedimentation...

  20. Calling behaviour under climate change: geographical and seasonal variation of calling temperatures in ectotherms.

    Science.gov (United States)

    Llusia, Diego; Márquez, Rafael; Beltrán, Juan F; Benítez, Maribel; do Amaral, José P

    2013-09-01

    Calling behaviour is strongly temperature-dependent and critical for sexual selection and reproduction in a variety of ectothermic taxa, including anuran amphibians, which are the most globally threatened vertebrates. However, few studies have explored how species respond to distinct thermal environments at time of displaying calling behaviour, and thus it is still unknown whether ongoing climate change might compromise the performance of calling activity in ectotherms. Here, we used new audio-trapping techniques (automated sound recording and detection systems) between 2006 and 2009 to examine annual calling temperatures of five temperate anurans and their patterns of geographical and seasonal variation at the thermal extremes of species ranges, providing insights into the thermal breadths of calling activity of species, and the mechanisms that enable ectotherms to adjust to changing thermal environments. All species showed wide thermal breadths during calling behaviour (above 15 °C) and increases in calling temperatures in extremely warm populations and seasons. Thereby, calling temperatures differed both geographically and seasonally, both in terrestrial and aquatic species, and were 8-22 °C below the specific upper critical thermal limits (CTmax ) and strongly associated with the potential temperatures of each thermal environment (operative temperatures during the potential period of breeding). This suggests that calling behaviour in ectotherms may take place at population-specific thermal ranges, diverging when species are subjected to distinct thermal environments, and might imply plasticity of thermal adjustment mechanisms (seasonal and developmental acclimation) that supply species with means of coping with climate change. Furthermore, the thermal thresholds of calling at the onset of the breeding season were dissimilar between conspecific populations, suggesting that other factors besides temperature are needed to trigger the onset of reproduction. Our

  1. Variation in surface air temperature of China during the 20th century

    Science.gov (United States)

    Soon, Willie; Dutta, Koushik; Legates, David R.; Velasco, Victor; Zhang, Weijia

    2011-10-01

    The 20th century surface air temperature (SAT) records of China from various sources are analyzed using data which include the recently released Twentieth Century Reanalysis Project dataset. Two key features of the Chinese records are confirmed: (1) significant 1920s and 1940s warming in the temperature records, and (2) evidence for a persistent multidecadal modulation of the Chinese surface temperature records in co-variations with both incoming solar radiation at the top of the atmosphere as well as the modulated solar radiation reaching ground surface. New evidence is presented for this Sun-climate link for the instrumental record from 1880 to 2002. Additionally, two non-local physical aspects of solar radiation-induced modulation of the Chinese SAT record are documented and discussed.Teleconnections that provide a persistent and systematic modulation of the temperature response of the Tibetan Plateau and/or the tropospheric air column above the Eurasian continent (e.g., 30°N-70°N; 0°-120°E) are described. These teleconnections may originate from the solar irradiance-Arctic-North Atlantic overturning circulation mechanism proposed by Soon (2009). Also considered is the modulation of large-scale land-sea thermal contrasts both in terms of meridional and zonal gradients between the subtropical western Pacific and mid-latitude North Pacific and the continental landmass of China. The Circum-global teleconnection (CGT) pattern of summer circulation of Ding and Wang (2005) provides a physical framework for study of the Sun-climate connection over East Asia. Our results highlight the importance of solar radiation reaching the ground and the concomitant importance of changes in atmospheric transparency or cloudiness or both in motivating a true physical explanation of any Sun-climate connection. We conclude that ground surface solar radiation is an important modulating factor for Chinese SAT changes on multidecadal to centennial timescales. Therefore, a

  2. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    H.-J. Lüdecke; A. Hempelmann; Weiss, C. O.

    2012-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the 6 instrumental records for analysis by discrete Fourier transformation (DFT), wavelets, and the detrended fluctuati...

  3. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    Lüdecke, H.-J.; A. Hempelmann; Weiss, C. O.

    2013-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detren...

  4. Graphical Interface for Measuring and Recording Temperature with the DS18B20 Digital Output Sensor

    Directory of Open Access Journals (Sweden)

    Viorel POPA

    2013-06-01

    Full Text Available The article presents the authors’ two originalgraphical interfaces made in Borland Delphi anddesigned to measure and record (with the DS18B20sensor a wide range of negative and positivetemperatures. The first interface allows the readingof a sensor’s unique code and then themeasurement and recording of temperature. Thesecond interface can work with a variable numberof such sensors once their unique code has beenentered.The interfaces have been conceived for thestudy of the slow variations of air temperatureinside chambers or wood, in timber freezing,heating or drying processes.To achieve the purpose we have alsoexperimented on other variants of temperaturesensors, but finally we have adopted the variantthat uses the DS18B20 digital output sensormanufactured by Dallas Company. This sensor hasthe following advantages:- a small size (it can be easily inserted into a 4mm diameter hole made in the wood piece;- it measures temperatures between -55°Cand +125°C;- it can relatively easily connect to the RS232serial port of a computer;- with only two wires one can ensure datainsertion and transmission from a numberof 4 ÷ 10 sensors of this type.

  5. NOAA Climate Data Record (CDR) of Atmospheric Layer Temperatures, Version 3.3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Atmospheric Layer Temperature Climate Data Record (CDR) dataset is a monthly analysis of the tropospheric and stratospheric data using temperature sounding...

  6. BASE Temperature Data Record (TDR) from the SSM/I and SSMIS Sensors, CSU Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The BASE Temperature Data Record (TDR) dataset from Colorado State University (CSU) is a collection of the raw unprocessed antenna temperature data that has been...

  7. Earlywood vessels of Castanea sativa record temperature before their formation.

    Science.gov (United States)

    Fonti, Patrick; Solomonoff, Natalie; García-González, Ignacio

    2007-01-01

    The aim of this study was to identify the climatic signal contained in the earlywood vessel size of the ring-porous chestnut (Castanea sativa) and the physiological processes involved in the underlying mechanisms. In order to assign the encoded signal to a specific physiological process, bud phenology and vessel formation were monitored along an elevation transect and chronologies of the size of the first row of earlywood vessels were retrospectively correlated with 40 yr of early spring temperatures. The first vessels appeared in late April to early May, after encoding both a negative temperature signal in February-March (during tree quiescence) and a positive temperature signal in early April (at the time of resumption of shoot growth). We hypothesize that February and March temperatures affect cambial sensitivity to auxin, preconditioning tree responses later in the season. Furthermore, April temperature is related to tree activation whereby new hormone production fosters vessel expansion.

  8. Temperature variation makes ectotherms more sensitive to climate change.

    Science.gov (United States)

    Paaijmans, Krijn P; Heinig, Rebecca L; Seliga, Rebecca A; Blanford, Justine I; Blanford, Simon; Murdock, Courtney C; Thomas, Matthew B

    2013-08-01

    Ectotherms are considered to be particularly vulnerable to climate warming. Descriptions of habitat temperatures and predicted changes in climate usually consider mean monthly, seasonal or annual conditions. Ectotherms, however, do not simply experience mean conditions, but are exposed to daily fluctuations in habitat temperatures. Here, we highlight how temperature fluctuation can generate 'realized' thermal reaction (fitness) norms that differ from the 'fundamental' norms derived under standard constant temperatures. Using a mosquito as a model organism, we find that temperature fluctuation reduces rate processes such as development under warm conditions, increases processes under cool conditions, and reduces both the optimum and the critical maximum temperature. Generalizing these effects for a range of terrestrial insects reveals that prevailing daily fluctuations in temperature should alter the sensitivity of species to climate warming by reducing 'thermal safety margins'. Such effects of daily temperature dynamics have generally been ignored in the climate change literature. © 2013 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

  9. Temperature and compositional variations in the Australian cratons

    Science.gov (United States)

    Tesauro, Magdala; Kaban, Mikhail; Aitken, Alan; Kennett, Brian

    2017-04-01

    The upper mantle of the Australian continent has been deeply investigated in the last two decades using a variety of geophysical methods. The resulting models have revealed the robust large-scale features of the continental lithosphere of Australia, i.e., faster seismic velocities in the Archean and Proterozoic cratons in the West, North and South Australia and slower velocities in the eastern Phanerozoic margin. Furthermore, it has been identified a layered velocity structure in central Australia. The zone of low seismic velocities in the uppermost mantle is underlain by the high-velocity zone. This layered structure may have a thermal origin, due to a redistribution of high heat producing elements within the crust or reflect compositional changes, e.g. a presence of amphibole. To discern temperature and compositional variations in the Australian upper mantle, we apply an iterative technique, which employs a joint inversion of the seismic tomography and gravity data. This technique consists in removing the effect of the crust from the observed gravity field and topography. In the second step, the residual mantle gravity field and residual topography are inverted to obtain a 3-D density model of the upper mantle. The inversion technique accounts for the notion that these fields are controlled by the same factors but in a different way (e.g., depending on depth and horizontal dimension of the heterogeneity.) This enables us to locate the position of principal density anomalies in the upper mantle. Afterwards, the thermal contribution to the density structure is estimated by inverting the seismic tomography model AusREM (http://rses.anu.edu.au/seismology/AuSREM/index.php). Based on the residual fields, we construct an initial compositional model of the upper mantle. In particular, a negative residual density anomaly is interpreted as the material having a larger Mg# and depleted in garnet and CPX Then, the initial thermal model is re-estimated with the new

  10. Daytime variation in ambient temperature affects skin temperatures and blood pressure: Ambulatory winter/summer comparison in healthy young women.

    Science.gov (United States)

    Martinez-Nicolas, Antonio; Meyer, Martin; Hunkler, Stefan; Madrid, Juan Antonio; Rol, Maria Angeles; Meyer, Andrea H; Schötzau, Andy; Orgül, Selim; Kräuchi, Kurt

    2015-10-01

    It is widely accepted that cold exposure increases peripheral vascular resistance and arterial blood pressure (BP) and, hence, increases cardiovascular risk primarily in the elderly. However, there is a lack of concomitantly longitudinal recordings at personal level of environmental temperature (PET) and cardiophysiological variables together with skin temperatures (STs, the “interface-variable” between the body core and ambient temperature). To investigate the intra-individual temporal relationships between PET, STs and BP 60 healthy young women (52 completed the entire study) were prospectively studied in a winter/summer design for 26 h under real life conditions. The main hypothesis was tested whether distal ST (Tdist)mediates the effect of PET-changes on mean arterial BP (MAP). Diurnal profiles of cardiophysiological variables (including BP), STs and PET were ambulatory recorded. Daytime variations between 0930 and 2030 h were analyzed in detail by intra-individual longitudinal path analysis. Additionally, time segments before, during and after outdoor exposure were separately analyzed. In both seasons short-term variations in PET were positively associated with short-term changes in Tdist (not proximal ST, Tprox) and negatively with those in MAP. However, long-term seasonal differences in daytime mean levels were observed in STs but not in BP leading to non-significant inter-individual correlation between STs and BP. Additionally, higher individual body mass index (BMI) was significantly associated with lower daytime mean levels of Tprox and higher MAP suggesting Tprox as potential mediator variable for the association of BMI with MAP. In healthy young women the thermoregulatory and BP-regulatory systems are closely linked with respect to short-term, but not long-term changes in PET. One hypothetical explanation could serve recent findings that thermogenesis in brown adipose tissue is activated in a cool environment, which could be responsible for the

  11. Cultivar variation in cotton photosynthetic performance under different temperature regimes

    Science.gov (United States)

    Cotton (Gossypium hirsutum L.) yields are impacted by overall photosynthetic production. Factors that influence crop photosynthesis are the plants genetic makeup and the environmental conditions. This study investigated cultivar variation in photosynthesis when plants were grown in the field under...

  12. A new Holocene record of geomagnetic secular variation from Windermere, UK

    Science.gov (United States)

    Avery, Rachael S.; Xuan, Chuang; Kemp, Alan E. S.; Bull, Jonathan M.; Cotterill, Carol J.; Fielding, J. James; Pearce, Richard B.; Croudace, Ian W.

    2017-11-01

    Paleomagnetic secular variation (PSV) records serve as valuable independent stratigraphic correlation and dating tools for marine and terrestrial sediment sequences, and enhance knowledge of geomagnetic field dynamics. We present a new radiocarbon-dated record (WINPSV-12K) of Holocene geomagnetic secular variation from Windermere, updating the existing 1981 UK master PSV curve. Our analyses used continuous U-channel samples taken from the center of four sediment cores retrieved from Windermere in 2012. The natural remanent magnetization (NRM) of each U-channel was measured before and after stepwise alternating field (AF) demagnetization on a superconducting rock magnetometer at intervals of 0.5-cm or 1-cm. The NRM data reveal a stable and well-defined primary magnetization. Component declinations and inclinations estimated using Principal Component Analysis (PCA) of NRM data from the four Windermere cores correlate well on their independent radiocarbon age models. The four records were stacked using a sliding window bootstrap method, resulting in a composite Holocene PSV record (WINPSV-12K). On millennial timescales WINPSV-12K correlates well with other records from Western Europe and the northern North Atlantic to a resolution of ∼1 kyr, given age uncertainties and spatial variability between records. WINPSV-12K also compares well to the CALS10k.2 and pfm9k.1a model predictions for Windermere. Key regionally-significant PSV inclination features of WINPSV-12K which correlate with other North Atlantic records include peaks at 5-6, 8.5, and 10 cal ka BP, and a trough at 7 cal ka BP. Key PSV declination features include the eastward swing from 5.5-2.3 cal ka BP followed by a major westward excursion at 2.3 cal ka BP, peaks at 1.1 and 7 cal ka BP, and troughs at 5.4 and 8.2 cal ka BP, with the caveat that an estimated magnetic lock-in delay of at least 100-200 yr is present. PSV variations on 1-3 kyr timescales are interpreted to represent strengthening and weakening

  13. Temperature variation makes ectotherms more sensitive to climate change

    OpenAIRE

    Paaijmans, Krijn P.; Heinig, Rebecca L; Seliga, Rebecca A; Blanford, Justine I.; Blanford, Simon; Murdock, Courtney C; Thomas, Matthew B

    2013-01-01

    Ectotherms are considered to be particularly vulnerable to climate warming. Descriptions of habitat temperatures and predicted changes in climate usually consider mean monthly, seasonal or annual conditions. Ectotherms, however, do not simply experience mean conditions, but are exposed to daily fluctuations in habitat temperatures. Here, we highlight how temperature fluctuation can generate ‘realized’ thermal reaction (fitness) norms that differ from the ‘fundamental’ norms derived under stan...

  14. Millennium-long summer temperature variations in the European Alps as reconstructed from tree rings

    Directory of Open Access Journals (Sweden)

    C. Corona

    2010-06-01

    Full Text Available This paper presents a reconstruction of the summer temperatures over the Greater Alpine Region (44.05°–47.41° N, 6.43°–13° E during the last millennium based on a network of 38 multi-centennial larch and stone pine chronologies. Tree ring series are standardized using an Adaptative Regional Growth Curve, which attempts to remove the age effect from the low frequency variations in the series. The proxies are calibrated using the June to August mean temperatures from the HISTALP high-elevation temperature time series spanning the 1818–2003. The method combines an analogue technique, which is able to extend the too short tree-ring series, an artificial neural network technique for an optimal non-linear calibration including a bootstrap technique for calculating error assessment on the reconstruction. About 50% of the temperature variance is reconstructed. Low-elevation instrumental data back to 1760 compared to their instrumental target data reveal divergence between (warmer early instrumental measurements and (colder proxy estimates. The proxy record indicates cool conditions, from the mid-11th century to the mid-12th century, related to the Oort solar minimum followed by a short Medieval Warm Period (1200–1420. The Little Ice Age (1420–1830 appears particularly cold between 1420 and 1820 with summers that are 0.8 °C cooler than the 1901–2000 period. The new record suggests that the persistency of the late 20th century warming trend is unprecedented. It also reveals significant similarities with other alpine reconstructions.

  15. Variations in automatically recorded rumination time as explained by variations in intake of dietary fractions and milk production, and between-cow variation.

    Science.gov (United States)

    Byskov, M V; Nadeau, E; Johansson, B E O; Nørgaard, P

    2015-06-01

    Individual recording of rumination time (RT) is now possible in commercial dairy herds, through development of a microphone-based sensor, which is able to record RT by the sound of rumination activity. The objectives of this study were to examine the relationship between daily RT and intakes of different dietary fractions, the relationship between RT in minutes per kilogram of dry matter intake (DMI) and milk production, and to examine the variation in RT within and between mid-lactating dairy cows. Data from 3 production trials were used in which a total of 27 different diets were fed. The data contained 761, 290, and 203 daily recordings of RT, milk yield, milk components, DMI, and intake of dietary fractions recorded on 29, 26, and 24 Holstein and Swedish Red cows from trials 1, 2, and 3, respectively. The dietary fractions included forage neutral detergent fiber (NDF), concentrate NDF, crude protein, sugar, starch, and the remaining fraction represented by organic matter--(forage NDF+concentrate NDF+crude protein+sugar+starch). The relationship between the dietary fractions and RT was analyzed in 2 steps. In step 1, the dietary fractions, which were significantly related to RT, were selected and simultaneously checked for multicollinearity between the dietary components; in step 2, a multivariate model, including the effect of repeated measurements, the main effect of the selected dietary fractions from step 1, random effects of cow(trial) and trial, and information on breed, days in milk, and parity was used to analyze the relationship between RT and the selected dietary fractions. Relationships between RT in minutes per kilogram of DMI and milk yield and milk components were analyzed, using the same multivariate model as in step 2. Approximately 32% of the variation in daily RT could be explained by variations in intakes of the dietary fractions, whereas 48% of the total variation in RT was accounted for by individual variations between cows. Intakes of

  16. Towards Structural Analysis of Audio Recordings in the Presence of Musical Variations

    Directory of Open Access Journals (Sweden)

    Müller Meinard

    2007-01-01

    Full Text Available One major goal of structural analysis of an audio recording is to automatically extract the repetitive structure or, more generally, the musical form of the underlying piece of music. Recent approaches to this problem work well for music, where the repetitions largely agree with respect to instrumentation and tempo, as is typically the case for popular music. For other classes of music such as Western classical music, however, musically similar audio segments may exhibit significant variations in parameters such as dynamics, timbre, execution of note groups, modulation, articulation, and tempo progression. In this paper, we propose a robust and efficient algorithm for audio structure analysis, which allows to identify musically similar segments even in the presence of large variations in these parameters. To account for such variations, our main idea is to incorporate invariance at various levels simultaneously: we design a new type of statistical features to absorb microvariations, introduce an enhanced local distance measure to account for local variations, and describe a new strategy for structure extraction that can cope with the global variations. Our experimental results with classical and popular music show that our algorithm performs successfully even in the presence of significant musical variations.

  17. A two-fold increase of carbon cycle sensitivity to tropical temperature variations.

    Science.gov (United States)

    Wang, Xuhui; Piao, Shilong; Ciais, Philippe; Friedlingstein, Pierre; Myneni, Ranga B; Cox, Peter; Heimann, Martin; Miller, John; Peng, Shushi; Wang, Tao; Yang, Hui; Chen, Anping

    2014-02-13

    Earth system models project that the tropical land carbon sink will decrease in size in response to an increase in warming and drought during this century, probably causing a positive climate feedback. But available data are too limited at present to test the predicted changes in the tropical carbon balance in response to climate change. Long-term atmospheric carbon dioxide data provide a global record that integrates the interannual variability of the global carbon balance. Multiple lines of evidence demonstrate that most of this variability originates in the terrestrial biosphere. In particular, the year-to-year variations in the atmospheric carbon dioxide growth rate (CGR) are thought to be the result of fluctuations in the carbon fluxes of tropical land areas. Recently, the response of CGR to tropical climate interannual variability was used to put a constraint on the sensitivity of tropical land carbon to climate change. Here we use the long-term CGR record from Mauna Loa and the South Pole to show that the sensitivity of CGR to tropical temperature interannual variability has increased by a factor of 1.9 ± 0.3 in the past five decades. We find that this sensitivity was greater when tropical land regions experienced drier conditions. This suggests that the sensitivity of CGR to interannual temperature variations is regulated by moisture conditions, even though the direct correlation between CGR and tropical precipitation is weak. We also find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming.

  18. Variations in automatically recorded rumination time as explained by variations in intake of dietary fractions and milk production, and between-cow variation

    DEFF Research Database (Denmark)

    Byskov, Malene Vesterager; Nadeau, E.; Johansson, B. E. O.

    2015-01-01

    contained 761, 290, and 203 daily recordings of RT, milk yield, milk components, DMI, and intake of dietary fractions recorded on 29, 26, and 24 Holstein and Swedish Red cows from trials 1, 2, and 3, respectively. The dietary fractions included forage neutral detergent fiber (NDF), concentrate NDF, crude...... selected and simultaneously checked for multicollinearity between the dietary components; in step 2, a multivariate model, including the effect of repeated measurements, the main effect of the selected dietary fractions from step 1, random effects of cow(trial) and trial, and information on breed, days...... of different dietary fractions, the relationship between RT in minutes per kilogram of dry matter intake (DMI) and milk production, and to examine the variation in RT within and between mid-lactating dairy cows. Data from 3 production trials were used in which a total of 27 different diets were fed. The data...

  19. Single-atom reversible recording at room temperature

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Lin, Rong

    2001-01-01

    A single hydrogen atom can be reversibly switched between two symmetric sites on a silicon dimer at the surface of Si(100) using a scanning tunnelling microscope (STM). This is a model binary switch for silicon-based atom-scale reversible data storage at room temperature. In this paper we...... is of crucial importance. With our equipment it was possible to create a row of four switches in a controlled way.(Some figures in this article are in colour only in the electronic version)....

  20. Consecutive record-breaking high temperatures marked the handover from hiatus to accelerated warming

    Science.gov (United States)

    Su, Jingzhi; Zhang, Renhe; Wang, Huijun

    2017-03-01

    Closely following the hiatus warming period, two astonishing high temperature records reached in 2014 and 2015 consecutively. To investigate the occurrence features of record-breaking high temperatures in recent years, a new index focusing the frequency of the top 10 high annual mean temperatures was defined in this study. Analyses based on this index shown that record-breaking high temperatures occurred over most regions of the globe with a salient increasing trend after 1960 s, even during the so-called hiatus period. Overlapped on the ongoing background warming trend and the interdecadal climate variabilities, the El Niño events, particularly the strong ones, can make a significant contribution to the occurrence of high temperatures on interannual timescale. High temperatures associated with El Niño events mainly occurred during the winter annual period. As the Pacific Decadal Oscillation (PDO) struggled back to its positive phase since 2014, the global warming returned back to a new accelerated warming period, marked by the record-breaking high temperatures in 2014. Intensified by the super strong El Niño, successive high records occurred in 2015 and 2016. Higher frequencies of record high temperatures would occur in the near future because the PDO tends to maintain a continuously positive phase.

  1. Consecutive record-breaking high temperatures marked the handover from hiatus to accelerated warming.

    Science.gov (United States)

    Su, Jingzhi; Zhang, Renhe; Wang, Huijun

    2017-03-03

    Closely following the hiatus warming period, two astonishing high temperature records reached in 2014 and 2015 consecutively. To investigate the occurrence features of record-breaking high temperatures in recent years, a new index focusing the frequency of the top 10 high annual mean temperatures was defined in this study. Analyses based on this index shown that record-breaking high temperatures occurred over most regions of the globe with a salient increasing trend after 1960 s, even during the so-called hiatus period. Overlapped on the ongoing background warming trend and the interdecadal climate variabilities, the El Niño events, particularly the strong ones, can make a significant contribution to the occurrence of high temperatures on interannual timescale. High temperatures associated with El Niño events mainly occurred during the winter annual period. As the Pacific Decadal Oscillation (PDO) struggled back to its positive phase since 2014, the global warming returned back to a new accelerated warming period, marked by the record-breaking high temperatures in 2014. Intensified by the super strong El Niño, successive high records occurred in 2015 and 2016. Higher frequencies of record high temperatures would occur in the near future because the PDO tends to maintain a continuously positive phase.

  2. Characterisation of Seasonal Temperature Variation in a Shallow, Urban Aquifer: Implications for the Sustainable Development of Ground Source Heating Systems

    Science.gov (United States)

    Patton, Ashley M.; Farr, Gareth J.; Boon, David P.; James, David R.

    2017-04-01

    Groundwater thermally enhanced by the Urban Heat Island effect can be utilised by ground source heating systems (GSHSs). However, the near subsurface is subject to seasonal temperature variation reflected in shallow groundwater that can differ by several degrees throughout the year. To sustainably manage the near surface thermal resource an understanding of factors which control variation in groundwater temperature and how these are transmitted through the aquifer is needed. We show that even in relatively small urban areas (Cardiff, U.K., situated on a shallow gravel aquifer) the Zone of Seasonal Fluctuation (ZSF) can vary in depth by 8m. GSHSs are more efficient if they are sited below the ZSF, where temperatures are more stable. In Spring 2014, 48 groundwater monitoring boreholes were profiled at a 1m resolution to measure groundwater temperature across Cardiff. These were reprofiled that Autumn and compared to the Spring temperatures, defining the ZSF. The average depth to the base of the ZSF was 9.5mbgl but ranged from 7.1-15.5mbgl. The amplitude of the differences between Spring and Autumn temperatures also varied. To better understand the high spatial variability 60 boreholes were instrumented with in situ temperature loggers, recording at half-hourly intervals. The first year's data revealed the amplitudes of temperature variation within boreholes with loggers at similar depths were not always consistent. It was also noted that lag times between air temperature and groundwater temperature were not uniform across the sites. The data also showed that where gravels occurred at shallower depths the ZSF tended to be shallower and lag times shorter. The wide spatial variability of the ZSF may be partially explained by differing landuse. Those boreholes in open, grassed areas showed a deeper ZSF than those in built-up areas but built-up areas generally showed the greatest variation between Spring and Autumn temperature profiles, suggesting heat loss from buildings

  3. Rheological modelling of physiological variables during temperature variations at rest

    Science.gov (United States)

    Vogelaere, P.; de Meyer, F.

    1990-06-01

    The evolution with time of cardio-respiratory variables, blood pressure and body temperature has been studied on six males, resting in semi-nude conditions during short (30 min) cold stress exposure (0°C) and during passive recovery (60 min) at 20°C. Passive cold exposure does not induce a change in HR but increases VO 2, VCO 2 Ve and core temperature T re, whereas peripheral temperature is significantly lowered. The kinetic evolution of the studied variables was investigated using a Kelvin-Voigt rheological model. The results suggest that the human body, and by extension the measured physiological variables of its functioning, does not react as a perfect viscoelastic system. Cold exposure induces a more rapid adaptation for heart rate, blood pressure and skin temperatures than that observed during the rewarming period (20°C), whereas respiratory adjustments show an opposite evolution. During the cooling period of the experiment the adaptative mechanisms, taking effect to preserve core homeothermy and to obtain a higher oxygen supply, increase the energy loss of the body.

  4. RF transconductor linearization robust to process, voltage and temperature variations

    NARCIS (Netherlands)

    Kundur Subramaniyan, H.; Klumperink, Eric A.M.; Srinivasan, Venkatesh; Kiaei, Ali; Nauta, Bram

    2015-01-01

    Software-defined radio receivers increasingly exploit linear RF V-I conversion, instead of RF voltage gain, to improve interference robustness. Unfortunately, the linearity of CMOS inverters, which are often used to implement V-I conversion, is highly sensitive to Process, Voltage and Temperature

  5. Temperature Variation of the Magnetic Structure of HoSb

    DEFF Research Database (Denmark)

    Andersen, Nils Axel; Kjems, Jørgen; Vogt, O.

    1980-01-01

    Neutron diffraction has been used to show that the magnetic moment vector in the antiferromagnet HoSb changes direction as a function of temperature below TN=5.7K. The experimental results are in qualitative agreement with a recent theoretical prediction by Jensen et al. (1980) which ascribe...

  6. Unusual variation of blocking temperature in bi-magnetic nanoparticles

    Science.gov (United States)

    Arteaga-Cardona, Fernando; Santillán-Urquiza, Esmeralda; Pal, Umapada; Méndoza-Álvarez, M. E.; Torres-Duarte, Cristina; Cherr, Gary N.; de la Presa, Patricia; Méndez-Rojas, Miguel Á.

    2017-11-01

    Ferrite nanoparticles with bi-magnetic layered structure were synthesized by a seed-mediated co-precipitation technique. The strategy of growing a second magnetic layer enhanced the magnetic saturation (Ms) of the nanostructures, with a very small increase in their blocking temperature (TB). In contrary to the common magnetic nanostructures of 10-15 nm size range, which manifest blocking temperatures around room temperature (≈300 K), the measured TB values of the bi-magnetic nanostructures are much lower. The experimental TB values of the bi-magnetic nanostructures are much lower than their theoretically predicted ones. Moreover, the TB of the nanoparticles varies unusually, decreasing with particle size beyond a certain value. The low blocking temperature and high Ms of the fabricated bi-magnetic nanoparticles indicate the seed-mediated coprecipitation is an effective method for designing magnetic nanostructures suitable for biomedical applications such as in magnetic hyperthermia treatment, where nanostructures of low TB and high Ms are required.

  7. Using record linkage to monitor equity and variation in screening programmes

    Directory of Open Access Journals (Sweden)

    O’Reilly Dermot

    2012-04-01

    Full Text Available Abstract Background Ecological or survey based methods to investigate screening uptake rates are fraught with many limitations which can be circumvented by record linkage between Census and health services datasets using variations in breast screening attendance as an exemplar. The aim of this current study is to identify the demographic, socio-economic factors associated with uptake of breast screening. Methods Record linkage study: combining 2001 Census data within the Northern Ireland Longitudinal Study (NILS with data relating to validated breast screening histories from the National Breast Screening System. A cohort was identified of 37,059 women aged 48-64 at the Census who were invited for routine breast screening in the three years following the Census. All cohort attributes were as recorded on the Census form. Results The record linkage methodology enabled the records of almost 40,000 of those invited for screening to be analysed at an individual level, exceeding the largest published survey by a factor of ten. This produced a more robust analysis and demonstrated (in fully adjusted models the lower uptake amongst non-married women and those in the lowest social class (OR 0.74; 95%CI 0.66, 0.82, factors that had not been reported earlier in the UK. In addition, with the availability of both individual and area information it was possible to show that the much lower screening uptake in urban areas is not due to differences in population composition suggesting unrecognised organisational problems. Conclusions Linkage of screening data to Census-based longitudinal studies is an efficient and powerful way to increase the evidence base on sources of variation in screening uptake within the UK.

  8. New and revised palaeomagnetic secular variation records from post-glacial volcanic materials in New Zealand

    Science.gov (United States)

    Greve, Annika; Turner, Gillian M.

    2017-08-01

    Global databases suffer from a paucity of palaeomagnetic secular variation (PSV) data from the SW Pacific region and are often affected by inconsistencies in data quality, or available age control of the sampled units. Here we present new PSV records obtained from post-glacial (≤15 kyrs BP) volcanic materials (mainly lavas) from New Zealand. The new dataset incorporates a compilation and critical assessment of all previous discrete PSV data and their age controls, and the results of new sampling in the Taupo Volcanic Zone. The overall dataset includes 23 directional and 10 absolute palaeointensity records primarily from lavas of rhyolitic or andesitic composition. Age constraints on the rhyolitic lavas are available from correlation with distal, radiocarbon dated tephra deposits, age controls on the andesites from field relationships or from 40Ar/39Ar dating. Directional swings, ranging from 326.5° to 26.0° declination and -81.4 to -46.3° inclination and intensity variations from 37.0 to 71.6 μT, fall well into the range of PSV expected for this time-frame in New Zealand and reproduce features of continuous sediment records.

  9. Variation of Atmospheric Oxygen in the Phanerozoic Recorded By δ13c of Terrestrial Organic Matter

    Science.gov (United States)

    Muehlenbachs, K.; Tappert, R.; McKellar, R. C.; Wolfe, A. P.; Tappert, M.; Schoell, M.

    2014-12-01

    One important factor controlling the δ13C of C3 plants is pO2 and thus δ13C of fossil terrestrial organic matter is a proxy for ancient pO2 once variations of δ13C of the atmosphere and paleo pCO2 are corrected for. We reconstructed pO2 since the emergence of land plants in the Ordovician following the approach of Tappert et al. [1], and using the published δ13C record of fossil resins (amber), coals and dispersed terrestrial organic matter. For most of this time, atmospheric pO2 was considerably lower (pO2 ~ 10-21%) compared to today (pO2 = 21%). Secular variations in pO2 must reflect changing amounts of burial of organic matter and sulfides. We observe a strong correlation between pO2 calculated from land plants, and the strontium and lithium isotopic compositions of marine carbonates. The marine Sr isotope record reflects secular changes of continental weathering and climate driven by tectonic activity. Synchronicity of pO2 with the marine strontium isotope record implies that tectonic processes, including orogeneses and the formation of associated sedimentary basins, not only control the rate of weathering and volume of sedimentation, but also the amount and proportion of the biomass that is buried on geological timescales.

  10. Variations of bubble cavitation and temperature elevation during acculysis

    Science.gov (United States)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2017-03-01

    High-intensity focused ultrasound (HIFU) is effective in both thermal ablations and soft-tissue fragmentation. Mechanical and thermal effects depend on the operating parameters and vary with the progress of therapy. Different types of lesions could be produced with the pulse duration of 5-30 ms, much longer than histotripsy burst but shorter than the time for tissue boiling, and pulse repetition frequency (PRF) of 0.2-5 Hz. Meanwhile, bubble cavitation and temperature elevation in the focal region were measured by passive cavitation detection (PCD) and thermocouples, respectively. Temperature in the pre-focal region is always higher than those at the focal and post-focal position in all tests. Overall, it is suggested that appropriate synergy and monitoring of mechanical and thermal effects would broaden the HIFU application and enhance its efficiency as well as safety.

  11. The temperature variation of hydrogen diffusion coefficients in metal alloys

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    Hydrogen diffusion coefficients were measured as a function of temperature for a few metal alloys using an electrochemical evolution technique. Results from these measurements are compared to those obtained by the time-lag method. In all cases, diffusion coefficients obtained by the electrochemical method are larger than those by the time-lag method by an order of magnitude or more. These differences are attributed mainly to hydrogen trapping.

  12. [Health consequences of environmental temperature and climate variations].

    Science.gov (United States)

    Swynghedauw, Bernard

    2012-01-01

    Recent climate change is a consequence of the greenhouse effect and human activity, and is directly responsible for extreme events such as heatwaves (see report of the French Académie des Sciences). Human thermoregulation depends more on behavior than on biology Air conditioning and building structure play an essential role. The 2003 heatwave was not a unique event. Preventive measures reduced mortality during subsequent heatwaves. Most deaths were due to heat stroke associated with dehydration. During strenuous exercise, especially during military training, heat stroke requires specific treatment. Temperature/ global mortality and temperature/cardiovascular mortality curves are both U-shaped. Usually, global mortality increases winter and is linked to temperature. During summer, global mortality increases only when heatwaves occur. Climate change participates in the spread of infectious diseases. Nevertheless, in continental France, for the moment, climate change is not a major factor in the incidence of infectious diseases, despite the fact that several bacteria, viruses and vectors are temperature-sensitive. The situation in Reunion, French Polynesia and French Departments of America is more complicated, due to their geographic heterogeneity. Some areas are more exposed to the climatic risk and could act as a gateway for new infections and mutations. The dramatic loss of biodiversity is partly a consequence of climate change. It increases the transmissibility of some pathogens and can also potentially lead to an increase in autoimmune diseases and obesity. Climate change plays a important role in allergic diseases, through changes in the diffusion and composition of pollens. These modifications are being monitored by several observatories. Six different veterinary diseases, including several zoonoses, are of particular concern.

  13. An instrument for recording the optical-path variation of transmitting objects.

    Science.gov (United States)

    Lamberts, R L

    1970-06-01

    An instrument is described for recording the variations in optical path length, particularly for small periodic line structures, in thin transparent objects. It is especially useful for studying relief images on photographic films and plates. The instrument contains an interference microscope in which the interference takes place between a beam transmitted by the sample and a reference beam which is generated by a Ronchi grating, passed through the sample, and subsequently spatially filtered. A helium-neon laser is used as a light source. The instrument also includes a system for scanning the interference fringes and recording the fringe shape in much the same manner that a microdensitometer records density. Because the system scans as many as forty fringes simultaneously, the averaging that is necessary for measuring the mean fringe contours of relatively coarse-grained photographic films is automatically provided. The fringe contour accurately describes the variation of optical path despite variations of density. Samples having spatial frequencies as high as several hundred lines per millimeter or more can be measured, depending upon the microscope optics and the nature of the sample. The lower spatial frequency limit depends upon the number of lines of the sample that are contained within the illuminated field of view of the microscope. Although focusing of the microscope was found to be quite critical, for most cases of interest sufficient focusing accuracy can be attained by using an auxiliary white light source. The instrument is convenient to operate and provides an accuracy that is considerably better than can be obtained with visual interference microscopes. With minor changes it can be adapted for operation as a conventional microdensitometer.

  14. Rayleigh-Bénard convection instability in the presence of temperature variation at the lower wall

    Directory of Open Access Journals (Sweden)

    Jovanović Miloš M.

    2012-01-01

    Full Text Available This paper analyzes the two-dimensional viscous fluid flow between two parallel plates, where the lower plate is heated and the upper one is cooled. The temperature difference between the plates is gradually increased during a certain time period, and afterwards it is temporarily constant. The temperature distribution on the lower plate is not constant in x-direction, and there is longitudinal sinusoidal temperature variation imposed on the mean temperature. We investigate the wave number and amplitude influence of this variation on the stability of Rayleigh-Benard convective cells, by direct numerical simulation of 2-D Navier-Stokes and energy equation.

  15. Quantitative estimation of temperature variations in plantar angiosomes: a study case for diabetic foot

    National Research Council Canada - National Science Library

    Peregrina-Barreto, H; Morales-Hernandez, L A; Rangel-Magdaleno, J J; Avina-Cervantes, J G; Ramirez-Cortes, J M; Morales-Caporal, R

    2014-01-01

    .... Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations...

  16. Quantitative Estimation of Temperature Variations in Plantar Angiosomes: A Study Case for Diabetic Foot

    National Research Council Canada - National Science Library

    Peregrina-Barreto, H; Morales-Hernandez, L. A; Rangel-Magdaleno, J. J; Avina-Cervantes, J. G; Ramirez-Cortes, J. M; Morales-Caporal, R

    2014-01-01

    .... Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations...

  17. Explaining growth variation over large spatial scales: Effects of temperature and food on walleye growth

    DEFF Research Database (Denmark)

    Mosgaard, Thomas; Venturelli, Paul; Lester, Nigel P.

    2012-01-01

    for among-lake variation in growth (e.g., food and temperature) has proved very difficult. Here, we use length at age and temperature data from hundreds of water bodies between 44⁰N to 53⁰N latitude to explain variation in immature growth of walleye (Sander vitreus), one of the most economically valuable...... the variation is productivity and a negative relationship indicates density-dependence. We found that variation in walleye growth among water bodies is largely explained by food productivity - not density-dependence. These results suggest that we can’t detect density-dependence among lakes when density......Most fishes exhibit strong spatial variation in growth. Because fish growth and production are tightly linked, quantifying and explaining variation in growth can mean the difference between successful management and unforeseen collapse. However, disentangling the factors that are responsible...

  18. NOAA Climate Data Record (CDR) of Sea Surface Temperature - WHOI, Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Ocean Surface Bundle (OSB) Climate Data Record (CDR) consist of three parts: sea surface temperature, near-surface atmospheric properties, and heat fluxes....

  19. [Temperature variation at the external root surface during Nd: YAG laser irradiation in the root canal in vitro].

    Science.gov (United States)

    Yuan-Gao, Li; Xiao, Wang; Kexian, Xie; Dan, Liu

    2014-10-01

    To assess the temperature variation of the root surface using Nd: YAG laser irradiation in the root canal with different power and to evaluate the safety of laser application on the periodontal region. Thirty extracted human teeth with single-roots were collected. The teeth were cross-sectioned in the cervical portion, standardizing the roots at a 12-mm length. The roots were used as specimen. The roots were radiographed in the buccal-lingual direction to measure the thickness of the proximal walls, by means of a digital radiographic system. The specimens were divided into three groups according to the laser potency (1.5, 3.0, and 4.5 W). Each group was subdivided into two subgroups according to laser frequency (15 and 30 Hz). With the Nd: YAG laser irradiation for 20 s, the temperature variation of the root surface was monitored by thermocouples located at different parts of the root external wall and recorded by digital thermometers. The groups irradiated with 4.5 W presented the greatest temperature variation (above 10°C), followed by 3.0 and 1.5 W. The temperatures were statistically different (P 0.05). The apical half of the root presented statistically higher temperature rises than the cervical half of the root (P temperature variation of the root surface was associated with laser power, irradiation time, and the thickness of dentin. Application of Nd: YAG laser in the root at 1.5 W for 20 s can safely be used in endodontic treatment.

  20. Effect of Periodic Surface Air Temperature Variations on Subsurface Thermal Structure with Vertical Fluid flow

    Science.gov (United States)

    D, R. V.; Ravi, M.; Srivastava, K.

    2016-12-01

    The influence of climate change on near subsurface temperatures is an important research topic for global change impact assessment at the regional scale. The varying temperature of the air over the surface in long term will disturb subsurface thermal structure. Groundwater flow is another important process which perturbs the thermal distribution into the subsurface. To investigate the effect of periodic air temperature on nonisothermal subsurface, one dimensional transient heat conduction-advection equation is solved numerically using finite element method. Thermal response of subsurface for periodic variations in surface air temperature (SAT) with robin type boundary condition on the surface with vertical ground water flow are calculated and the amplitude attenuation of propagation of surface temperature information in the subsurface for different scenarios of advection and convective coefficient are discussed briefly. The results show the coupled response of trigonometric variation in air temperature with surface temperatures along with ground water velocity has significant implications for the effects of climate change.

  1. Spatial Analysis of Abyssal Temperature Variations Observed From the ALOHA Cabled Observatory and WHOTS Moorings

    Science.gov (United States)

    Santiago-Mandujano, F.; Lukas, R.; Howe, B. M.; Plueddemann, A. J.; Weller, R. A.; Deppe, R. W.; Larson, N. G.; Murphy, D. J.; Guenther, R.

    2016-02-01

    The ALOHA Cabled Observatory (ACO) has measured temperature variations at 4726 m (1.8 mab) in the Kauai Deep since June 2011. Starting in June 2012, temperatures 37 m above bottom were also measured from the Woods Hole-Hawaii Ocean Time-series Site (WHOTS)-9 (-10) moorings approximately 11 km to the east (10 km to the southeast) of the ACO, at depths of 4631 (4720) m. RMS potential temperature (θ) differences between ACO and WHOTS were 4.2 mK over 2 years, significantly greater than the accuracy and precision of the Sea-Bird instruments that were used. From mid-2013 onward, three distinct cold events were observed at each of the sites. Two events in 2014 saw drops in temperature >20 mK over only a few days, followed by large oscillations (10-60 days) of about 10 mK. ACO-WHOTS Δθs were greater than 5 mK on numerous occasions during these events, lasting days to weeks. During the 3-day overlap of the WHOTS-9 and -10 moorings (separated by 12 km meridionally and 89 m vertically), dual temperature sensors on each mooring showed near-bottom θ colder than the ACO by 5-8 mK and 3 mK respectively. ACO/WHOTS-9(-10) Δθs were largest during these events suggesting that relatively small spatial scales are important in the dynamics of the cold events in the Kauai Deep. The correlation of WHOTS-9(-10) abyssal θ with the ACO record was 0.69 (0.66). Cross-spectra of Δθ are distinctly different for the two mooring periods, with squared coherence > 0.8 for periods longer than 114 days during the cold events observed by WHOTS-10. A relative coherence peak near 20 days is found in both cases. Temperature - velocity spectra and cross-spectra also suggest energetic non-tidal dynamics.

  2. Simultaneous in vivo recording of local brain temperature and electrophysiological signals with a novel neural probe

    Science.gov (United States)

    Fekete, Z.; Csernai, M.; Kocsis, K.; Horváth, Á. C.; Pongrácz, A.; Barthó, P.

    2017-06-01

    Objective. Temperature is an important factor for neural function both in normal and pathological states, nevertheless, simultaneous monitoring of local brain temperature and neuronal activity has not yet been undertaken. Approach. In our work, we propose an implantable, calibrated multimodal biosensor that facilitates the complex investigation of thermal changes in both cortical and deep brain regions, which records multiunit activity of neuronal populations in mice. The fabricated neural probe contains four electrical recording sites and a platinum temperature sensor filament integrated on the same probe shaft within a distance of 30 µm from the closest recording site. The feasibility of the simultaneous functionality is presented in in vivo studies. The probe was tested in the thalamus of anesthetized mice while manipulating the core temperature of the animals. Main results. We obtained multiunit and local field recordings along with measurement of local brain temperature with accuracy of 0.14 °C. Brain temperature generally followed core body temperature, but also showed superimposed fluctuations corresponding to epochs of increased local neural activity. With the application of higher currents, we increased the local temperature by several degrees without observable tissue damage between 34-39 °C. Significance. The proposed multifunctional tool is envisioned to broaden our knowledge on the role of the thermal modulation of neuronal activity in both cortical and deeper brain regions.

  3. Millennial-scale Climate Variations Recorded As Far Back As The Early Pliocene

    Science.gov (United States)

    Steenbrink, J.; Hilgen, F. J.; Lourens, L. J.

    Quaternary climate proxy records show compelling evidence for climate variability on time scales of a few thousand years. The causes for these millennial-scale or sub- Milankovitch cycles are yet poorly understood, not in the least due to the complex feedback mechanisms of large ice-sheets during the Quaternary. We present evidence of millennial-scale climate variability in Early Pliocene lacustrine sediments from the intramontane Ptolemais Basin in northwestern Greece. The sediments are well ex- posed in a series of open-pit lignite mines and exhibit a distinct m-scale sedimentary cyclicity of alternating lignites and lacustrine marl beds that result from precession- induced variations in climate. A higher-frequency cyclicity is particular prominent within the marl segment of individual cycles. A stratigraphic interval of~115 kyr, cov- ering five precession-induced sedimentary cycles, was studied in nine parallel sections from two quarries located several km apart. Colour reflectance records were used to quantify the within-cycle variability and to determine its lateral continuity. Much of the within-cycle variability could be correlated between the parallel sections, even in fine detail, which suggests that these changes reflect basin-wide variations in environ- mental conditions related to (regional) climate fluctuations. Interbedded volcanic ash beds demonstrate the synchronicity of these fluctuations and spectral analysis of the reflectance time series shows a significant concentration of variability at periods of ~11,~5.5 and~2 kyr. Their occurrence at times before the intensification of the North- ern Hemisphere glaciation suggests that they cannot solely have resulted from internal ice-sheet dynamics. Possible candidates include harmonics or combination tones of the main orbital cycles, variations in solar output or periodic motions of the Earth and moon.

  4. Seasonal variation of air temperature at the Mendel Station, James Ross Island in the period of 2006-2009

    Science.gov (United States)

    Laska, Kamil; Prošek, Pavel; Budík, Ladislav

    2010-05-01

    Key words: air temperature, seasonal variation, James Ross Island, Antarctic Peninsula Recently, significant role of the atmospheric and oceanic circulation variation on positive trend of near surface air temperature along the Antarctic Peninsula has been reported by many authors. However, small number of the permanent meteorological stations located on the Peninsula coast embarrasses a detail analysis. It comprises analysis of spatiotemporal variability of climatic conditions and validation of regional atmospheric climate models. However, geographical location of the Czech Johann Gregor Mendel Station (hereafter Mendel Station) newly established on the northern ice-free part of the James Ross Island provides an opportunity to fill the gap. There are recorded important meteorological characteristics which allow to evaluate specific climatic regime of the region and their impact on the ice-shelf disintegration and glacier retreat. Mendel Station (63°48'S, 57°53'W) is located on marine terrace at the altitude of 7 m. In 2006, a monitoring network of several automatic weather stations was installed at different altitudes ranging from the seashore level up to mesas and tops of glaciers (514 m a.s.l.). In this contribution, a seasonal variation of near surface air temperature at the Mendel Station in the period of 2006-2009 is presented. Annual mean air temperature was -7.2 °C. Seasonal mean temperature ranged from +1.4 °C (December-February) to -17.7 °C (June-August). Frequently, the highest temperature occurred in the second half of January. It reached maximum of +8.1 °C. Sudden changes of atmospheric circulation pattern during winter caused a large interdiurnal variability of air temperature with the amplitude of 30 °C.

  5. Does the anti-hypertensive drug clonidine affect the short-term variation in CTG recordings?

    Science.gov (United States)

    Thornton, Charlene E; Makris, Angela; Tooher, Jane M; Ogle, Robert F; Hennessy, Annemarie

    2010-10-01

    Cardiotocographic (CTG) recordings of the fetal heart remain standard obstetric practice among hypertensive women. Changes in the short-term variation (STV) in the fetal heart are often attributed to the effect of anti-hypertensive medications, regardless of the fact that this principle has never been validated. To assess the STV of CTG recordings pre- and post- the anti-hypertensive medication, clonidine. Forty hypertensive pregnant women, already receiving the anti-hypertensive clonidine, were recruited. The CTGs were conducted pre- and post-dose administration. The CTGs were assessed by the Sonicaid Team® automated CTG analysis (Oxford Instruments, UK) to avoid CTG assessor bias. Baseline fetal heart rate (FHR) (delta change from pre- and post-dose) and STV were compared using spss v.14® utilising Student t-tests. No statistical difference was found in the pre- and post-baseline FHRs (P = 0.48). The mean delta baseline heart rate before and after drug administration was -0.54 bpm. The STV of the CTGs recorded pre- and post-clonidine dose was also not affected by administration of the drug (P = 0.34). The mean delta STV before and after drug administration was 0.39 ms. Two women received betamethasone 12 mg intramuscularly within the 12-h period prior to CTG recordings to enhance fetal lung maturity. The mean STV for the fetuses of these women pre-drug was 4.8 ms and 13.2 ms post-administration. This was the largest delta seen in all STVs recorded in this dataset. The anti-hypertensive drug clonidine does not alter baseline FHRs or affect the STV of the FHR in hypertensive pregnant women. © 2010 The Authors. Australian and New Zealand Journal of Obstetrics and Gynaecology © 2010 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  6. Photographic Records Showing the Variations of the Virtual Height of Reflection as a Function of the Radio Frequency

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standard (analog) ionosonde produces photographic records known as ionograms, which show the variations of the virtual height of reflection as a function of the...

  7. Body temperature variation of South African antelopes in two climatically contrasting environments

    NARCIS (Netherlands)

    Shrestha, A.K.; Wieren, van S.E.; Langevelde, van F.; Fuller, A.; Hetem, R.S.; Meyer, L.C.R.; Bie, de S.; Prins, H.H.T.

    2012-01-01

    To understand the adaptive capacity of a species in response to rapid habitat destruction and climate change, we investigated variation in body temperature (Tb) of three species of antelope, namely eland, blue wildebeest and impala, using abdominally-implanted temperature data loggers. The study was

  8. Regional and circadian variations of sweating rate and body surface temperature in camels (Camelus dromedarius).

    Science.gov (United States)

    Abdoun, Khalid A; Samara, Emad M; Okab, Aly B; Al-Haidary, Ahmed A

    2012-07-01

    It was the aim of this study to investigate the regional variations in surface temperature and sweating rate and to visualize body thermal windows responsible for the dissipation of excess body heat in dromedary camels. This study was conducted on five dromedary camels with mean body weight of 450 ± 20.5 kg and 2 years of age. Sweating rate, skin and body surface temperature showed significant (P surface temperature measured on seven regions of the camel body did not significantly differ. The variation in body surface temperature compared to the variation in skin temperature was higher in the hump compared to the axillary and flank regions, indicating the significance of camel's fur in protecting the skin from daily variation in ambient temperature. Infrared thermography revealed that flank and axillary regions had lower thermal gradients at higher ambient temperature (T(a) ) and higher thermal gradients at lower T(a) , which might indicate the working of flank and axillary regions as thermal windows dissipating heat during the night. Sweating rate showed moderate correlation to skin and body surface temperatures, which might indicate their working as potential thermal drivers of sweating in camels. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

  9. Effect of periodic temperature variations on the microstructure of neutron-irradiated metals

    DEFF Research Database (Denmark)

    Zinkle, S.J.; Hashimoto, N.; Hoelzer, D.T.

    2002-01-01

    Specimens of pure copper, a high purity austenitic stainless steel, and V–4Cr–4Ti were exposed to eight cycles of either constant temperature or periodic temperature variations during neutron irradiation in the High Flux Isotopes Reactor to a cumulative damage level of 4–5 displacements per atom....

  10. Weibull strength variations between room temperature and high temperature Ni-3YSZ half-cells

    DEFF Research Database (Denmark)

    Curran, Declan; Frandsen, Henrik Lund; Hendriksen, Peter Vang

    2013-01-01

    efficiency, increased degradation and/or the complete termination of a functioning stack. This paper investigates the effects of temperature on the mechanical strength of 3% yttria-stabilised zirconia half-cells. Strength was measured using a four-point bend method at room temperature and at 600°C, 700°C...... and 800°C in a reducing atmosphere. The strength of an as sintered half-cell was also measured at room temperature for comparison. Weibull analysis was performed on large sample sets of 30 for statistical viability. The Weibull strength and elastic modulus of the room temperature tested reduced samples...... show a decrease of approximately 33% and 51% respectively, when compared to the oxidized samples tested at room temperature. When tested at elevated temperatures both Weibull strength and elastic modulus decrease further when compared to the room temperature reduced samples. However these further...

  11. Detection of anthropogenic influences on the evolution of temperature records over Europe

    Science.gov (United States)

    Bador, M.; Terray, L.

    2013-12-01

    Extreme events have significant impacts and are among the most serious challenges to society. Here we focus on extreme temperature events, which can cost human lives and affect several sectors (energy, agriculture, water resources, etc), as it happened during the 2003 heat wave in France. One way to study extreme temperature events is the analysis of the occurrence and values of temperature records. By definition, an upper or lower record breaking occurs when a higher or lower value of maximum or minimum surface temperature appears in the annual time series, recorded since an initial date and dependent of the calendar days. This study focuses on the mean upper and lower record occurrence changes over Europe during the 20th and 21st century. In a stationary climate, the occurrence of record breaking temperatures can be expressed by simple probabilistic laws. However, it has been shown using observations that since the beginning of the 1980s the number of record breaking temperature in Europe no longer follows these laws (Wergen and Krug 2010, among others). An increase or decrease in the mean number of upper or lower records is found compared to the stationary climate breaking rate. To understand these changes we use a set of historical (1850-2005) simulations performed with the CNRM-CM5 model. We first use a 10-member ensemble with anthropogenic and natural forcings to calculate the evolution of daily temperature record occurrences. We find the same behavior as in the observations: the upper and lower records diverge from the stationary climate record breaking rate from the 1980's. We then use two other ensembles to attribute these changes to a given set of forcings (either anthropogenic or natural). We show that the simulated record changes from 1980 onwards are mostly due to anthropogenic effects. Using a long (850-year) preindustrial simulation with constant forcings, we also assess these changes with regards to the model internal variability. We then analyze

  12. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Pacific Remote Island Areas from 2011 to 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  13. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in American Samoa from 2012 to 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  14. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Hawaiian Archipelago from 2010 to 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  15. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Marianas Archipelago from 2011 to 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  16. An independently dated 4200-yr paleomagnetic secular variation record from the Chukchi Sea, Arctic Ocean

    Science.gov (United States)

    West, Gabriel; O'Regan, Matt; Jakobsson, Martin; Nilsson, Andreas; Pearce, Christof; Snowball, Ian; Wiers, Steffen

    2017-04-01

    Developing highly-tuned and accurate age models for Arctic Ocean sediments has been a long-standing problem in marine geosciences. This problem stems from the often microfossil poor content of these sediments and low sedimentation rates away from continental margins. The absence of reliable chronologies limits our ability to interpret increasingly sophisticated proxies for past environmental changes in this sensitive ocean basin, and prevents the integration of Arctic paleoceanographic time series with terrestrial, lacustrine and ice core records. While paleomagnetism has the potential to help resolve this problem, there is a scarcity of independently dated records from the Arctic and an incomplete understanding of mechanisms by which sediments become magnetized. Recently published results from a few western Arctic Ocean sediments illustrate that patterns and variability in Holocene paleosecular variation appear consistent with low latitude North American records and output from spherical harmonic geomagnetic field models. However, these marine records are constrained by only a few, and in some cases no, independent age data. Here we present a detailed paleo- and environmental magnetic record from an 8.24 m long sediment core (SWERUS-L2-2-PC1) collected at 57 m water depth in the Herald Canyon, Chukchi Sea of the Arctic Ocean (72.52°N 175.32°W). An independent age model for the core, which covers the last 4200 years, was derived from 14 AMS 14C dates and the identification of a tephra layer associated with the 3.6 cal ka BP Aniakchak eruption. The age model indicates average sedimentation rates of 200 cm/kyr. Variability in the paleomagnetic declination and inclination conform well to predictions made by time-varying geomagnetic field models (CALS10k.1b and CALS3K.4e) and can be readily correlated to other published PSV records from the Western Arctic that lack independent age control. The Late Holocene PSV record from SWERUS-L2-2-PC1 has the potential to be one

  17. Modelling the variation of land surface temperature as determinant of risk of heat-related health events

    Science.gov (United States)

    2011-01-01

    Background The evaluation of exposure to ambient temperatures in epidemiological studies has generally been based on records from meteorological stations which may not adequately represent local temperature variability. Here we propose a spatially explicit model to estimate local exposure to temperatures of large populations under various meteorological conditions based on satellite and meteorological data. Methods A general linear model was used to estimate surface temperatures using 15 LANDSAT 5 and LANDSAT 7 images for Quebec Province, Canada between 1987 and 2002 and spanning the months of June to August. The images encompassed both rural and urban landscapes and predictors included: meteorological records of temperature and wind speed, distance to major water bodies, Normalized Differential Vegetation Index (NDVI), land cover (built and bare land, water, or vegetation), latitude, longitude, and week of the year. Results The model explained 77% of the variance in surface temperature, accounting for both temporal and spatial variations. The standard error of estimates was 1.42°C. Land cover and NDVI were strong predictors of surface temperature. Conclusions This study suggests that a statistical approach to estimating surface temperature incorporating both spatially explicit satellite data and time-varying meteorological data may be relevant to assessing exposure to heat during the warm season in the Quebec. By allowing the estimation of space- and time-specific surface temperatures, this model may also be used to assess the possible impacts of land use changes under various meteorological conditions. It can be applied to assess heat exposure within a large population and at relatively fine-grained scale. It may be used to evaluate the acute health effect of heat exposure over long time frames. The method proposed here could be replicated in other areas around the globe for which satellite data and meteorological data is available. PMID:21251286

  18. Modelling the variation of land surface temperature as determinant of risk of heat-related health events.

    Science.gov (United States)

    Kestens, Yan; Brand, Allan; Fournier, Michel; Goudreau, Sophie; Kosatsky, Tom; Maloley, Matthew; Smargiassi, Audrey

    2011-01-21

    The evaluation of exposure to ambient temperatures in epidemiological studies has generally been based on records from meteorological stations which may not adequately represent local temperature variability. Here we propose a spatially explicit model to estimate local exposure to temperatures of large populations under various meteorological conditions based on satellite and meteorological data. A general linear model was used to estimate surface temperatures using 15 LANDSAT 5 and LANDSAT 7 images for Quebec Province, Canada between 1987 and 2002 and spanning the months of June to August. The images encompassed both rural and urban landscapes and predictors included: meteorological records of temperature and wind speed, distance to major water bodies, Normalized Differential Vegetation Index (NDVI), land cover (built and bare land, water, or vegetation), latitude, longitude, and week of the year. The model explained 77% of the variance in surface temperature, accounting for both temporal and spatial variations. The standard error of estimates was 1.42°C. Land cover and NDVI were strong predictors of surface temperature. This study suggests that a statistical approach to estimating surface temperature incorporating both spatially explicit satellite data and time-varying meteorological data may be relevant to assessing exposure to heat during the warm season in the Quebec. By allowing the estimation of space- and time-specific surface temperatures, this model may also be used to assess the possible impacts of land use changes under various meteorological conditions. It can be applied to assess heat exposure within a large population and at relatively fine-grained scale. It may be used to evaluate the acute health effect of heat exposure over long time frames. The method proposed here could be replicated in other areas around the globe for which satellite data and meteorological data is available.

  19. Morphological features and variations of temperature in the upper thermosphere simulated by a whole atmosphere GCM

    Directory of Open Access Journals (Sweden)

    H. Fujiwara

    2010-02-01

    Full Text Available In order to illustrate morphological features and variations of temperature in the upper thermosphere, we performed numerical simulations with a whole atmosphere general circulation model (GCM for the solar minimum and geomagnetically quiet conditions in March, June, September, and December. In previous GCMs, tidal effects were imposed at the lower boundaries assuming dominant diurnal and semi-diurnal tidal modes. Since the GCM used in the present study covers all the atmospheric regions, the atmospheric tides with various modes are generated within the GCM. The global temperature distributions obtained from the GCM are in agreement with ones obtained from NRLMSISE-00. In addition, the GCM also represents localised temperature structures which are superimposed on the global day-night distributions. These localised structures, which vary from hour to hour, would be observed as variations with periods of about 2–3 h at a single site. The amplitudes of the 2–3 h variations are significant at high-latitude, while the amplitudes are small at low-latitude. The diurnal temperature variation is more clearly identified at low-latitude than at high-latitude. When we assume the same high-latitude convection electric field in each month, the temperature calculated in the polar cap region shows diurnal variation more clearly in winter than in summer. The midnight temperature maximum (MTM, which is one of the typical low-latitude temperature structures, is also seen in the GCM results. The MTMs in the GCM results show significant day-to-day variation with amplitudes of several 10s to about 150 K. The wind convergence and stream of warm air are found around the MTM. The GCM also represent the meridional wind reversals and/or abatements which are caused due to local time variations of airflow pattern in the low-latitude region.

  20. Variation in Yield Responses to Elevated CO₂ and a Brief High Temperature Treatment in Quinoa.

    Science.gov (United States)

    Bunce, James A

    2017-07-05

    Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO₂ and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 ("ambient") and 600 ("elevated") μmol·mol(-1) CO₂ concentrations at 20/14 °C day/night ("control") temperatures, with or without exposure to day/night temperatures of 35/29 °C ("high" temperatures) for seven days during anthesis. At control temperatures, the elevated CO₂ concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO₂ occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO₂ ranged from 12% to 44% among cultivars at the control temperature. At ambient CO₂, the week-long high temperature treatment greatly decreased (0.30 × control) or increased (1.70 × control) seed yield, depending on the cultivar. At elevated CO₂, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO₂ and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO₂ than other crops that have been examined.

  1. Variations of magnetic properties in thin lava flow profiles: Implications for the recording of the Laschamp Excursion

    Science.gov (United States)

    Vérard, Christian; Leonhardt, Roman; Winklhofer, Michael; Fabian, Karl

    2012-06-01

    Two blocks have been cut in two lava flows from the Skalamaelifell Hill (Iceland) known to have recorded the Laschamp magnetic excursion (40.4 ± 2.0 ka). Detailed sampling and analyses have revealed multiple magnetic components. The high temperature/coercivity component corresponds to the primary magnetisation, with corresponding pole position close to the equator in the Pacific Ocean (φ = 251.90°/λ = -06.49°; dp = 0.74°/dm = 2.12°) and palaeo-intensity determinations below 5 μT. The different VGPs, however, vary in relation with the position of samples in the profiles. It could not be firmly established whether this distribution is associated with a change in the Earth magnetic field during lava cooling. In any case, variations are related with zones in the profiles marked, in particular, by the presence of vesicles. Moreover, the other components are interpreted to be linked with alteration inside the rocks, caused by interactions between vesicles content and the surrounding matrix. Secondary component, however, is interpreted as recording an excursional magnetic field, and should be of greater consideration in studies of Earth magnetic field excursions or reversals.

  2. Effect of camera temperature variations on stereo-digital image correlation measurements

    KAUST Repository

    Pan, Bing

    2015-11-25

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30–50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  3. Effect of Temperature Variation on Modal Frequency of Reinforced Concrete Slab and Beam in Cold Regions

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-01-01

    Full Text Available Changes of modal frequencies induced by temperature variation can be more obvious than those caused by structural damage, which will lead to the false damage identification results. Therefore, quantifying the temperature effect on modal frequencies is a critical step to eliminate its interference in damage detection. Due to the nonuniform and time-dependent characteristics of temperature distribution, it is insufficient to obtain the reliable relationships between temperatures and modal frequencies using temperatures in air or at surface. In this paper, correlations between measured temperatures (air temperature, surface temperature, mean temperature, etc. and modal frequencies for the slab and beam are comparatively analyzed. And the quantitative models are constructed considering nonuniform temperature distribution. Firstly, the reinforced concrete slab and beam were constructed and placed outside the laboratory to be monitored. Secondly, the correlation coefficients between modal frequencies and three kinds of temperatures are calculated, respectively. Thirdly, simple linear regression models between mean temperature and modal frequencies are established for the slab and beam. Finally, five temperature variables are selected to construct the multiple linear regression models. Prediction results reveal that the proposed multiple linear regression models possess favorable accuracy to quantify the temperature effect on modal frequencies considering nonuniform temperature distribution.

  4. Variation of Mo isotopes from molybdenite in high-temperature hydrothermal ore deposits

    Science.gov (United States)

    Mathur, Ryan; Brantley, S.; Anbar, A.; Munizaga, F.; Maksaev, V.; Newberry, R.; Vervoort, J.; Hart, G.

    2010-01-01

    Measurable molybdenum isotope fractionation in molybdenites from different ore deposits through time provides insights into ore genesis and a new technique to identify open-system behavior of Re-Os in molybdenites. Molybdenite samples from six porphyry copper deposits, one epithermal polymetallic vein deposit, four skarns, and three Fe-oxide Cu-Au deposits were analyzed. The δ97Mo‰ (where [InlineEquation not available: see fulltext.]) for all samples varied from 1.34 ± 0.09‰ to -0.26 ± 0.04‰. This is the largest molybdenum isotopic variation in molybdenite from high-temperature ore deposits recorded to date. δ97Mo‰ of molybdenite varies as a function of the deposit type and the rhenium and osmium concentrations of the samples. Isotope values for Mo also vary within the individual deposits. In general, molybdenites from porphyry copper deposits have the lightest values averaging 0.07 ± 0.23‰ (1 σ). Molybdenites from the other deposit types average 0.49 ± 0.26‰ (1 σ). The variations could be related to the fractionation of Mo into different mineral phases during the ore-forming processes. A comparison of the Mo isotope ratios and the Re-Os ages obtained from the same aliquot may possess a geochronological evaluation tool. Samples that yielded robust ages have different Mo isotopic compositions in comparison to samples that yielded geologically unreasonable ages. Another observed relationship between the Re-Os and Mo isotope data reveals a weak correspondence between Re concentration and Mo isotope composition. Molybdenites with higher concentrations of Re correspond to lighter Mo isotope values.

  5. Daytime ozone and temperature variations in the mesosphere: a comparison between SABER observations and HAMMONIA model

    Directory of Open Access Journals (Sweden)

    S. Dikty

    2010-09-01

    Full Text Available This paper investigates the latest version 1.07 SABER (Sounding of the Atmosphere using Broadband Emission Radiometry tropical ozone from the 1.27 μm as well as from the 9.6 μm retrieval and temperature data with respect to day time variations in the upper mesosphere. The processes involved are compared to day time variations of the three-dimensional general circulation and chemistry model HAMMONIA (Hamburg Model of the Neutral and Ionized Atmosphere. The results show a good qualitative agreement for ozone. The amplitude of daytime variations is in both cases approximately 60% of the daytime mean. During equinox the daytime maximum ozone abundance is for both, the observations and the model, higher than during solstice, especially above 0.01 hPa (approx. 80 km. The influence of tidal signatures either directly in ozone or indirectly via a temperature response above 0.01 hPa can not be fully eliminated. Below 0.01 hPa (photo-chemistry is the main driver for variations. We also use the HAMMONIA output of daytime variation patterns of several other different trace gas species, e.g., water vapor and atomic oxygen, to discuss the daytime pattern in ozone. In contrast to ozone, temperature data show little daytime variations between 65 and 90 km and their amplitudes are on the order of less than 1.5%. In addition, SABER and HAMMONIA temperatures show significant differences above 80 km.

  6. Body temperature variations of the Louisiana pine snake (Pituophis ruthveni) in a longleaf pine ecosystem

    Science.gov (United States)

    John G. Himes; Laurence M. Hardy; D. Craig Rudolph; Shirley J. Burgdorf

    2006-01-01

    The thermal ecology of the Louisiana pine snake, Pituophis ruthveni, was studied from 1993-97 in Louisiana and Texas. All snakes were implanted with temperature-sensitive radiotransmitters. Temperatures were recorded from snakes located above ground and underground and were compared between size and sex classes (juveniles, adult males, adult females). Associated air...

  7. Long-term variations of fumarole temperatures on Vulcano Island (Italy

    Directory of Open Access Journals (Sweden)

    Iole Serena Diliberto

    2011-06-01

    Full Text Available Fumarole temperatures are the ultimate results of many processes that are encountered by deep fluids during their passage to the surface. Here, the time variations of high-temperature fumaroles acquired by continuous monitoring are presented, to show the effects of the forces that act on the system. Data acquired by continuous monitoring of fumaroles and the time relationships with the different parameters related to the activity of the volcanic system are discussed. From 1998 to 2010, the temperature and compositional changes of fumarolic gases were monitored at the same time as variations in the number of volcano-seismic events, which indicate frequent variations of energy release (heat and mass flow, and seismic strain release. Geochemical modeling applied to the volcanic system of Vulcano Island suggests that the overall expansion of magmatic gas through the fractured system is an almost iso-enthalpic process at depth, which shifts to an adiabatic process at shallow depth, where the rock permeability increases. Thus, the time variations of the fumarole temperatures reflect various physical variations of the system that can either occur at depth or close to the surface. The temperature monitoring performed in the fumarolic area of La Fossa Cone showed short-term effects related to rain events, and negligible effects related to other external agents (ambient temperature and atmospheric pressure variations. At the same time, the long-term monitoring highlighted some mean-term and long-term variations. These last are the main characters observed in the time-series, and they both appear to be related to endogenous forces that perturb the equilibrium of this complex geochemical system.

  8. A Comparison of Two Air-Temperature Records From Barrow, Alaska, 1976-2004

    Science.gov (United States)

    Klene, A. E.

    2005-12-01

    The National Weather Service (NWS) air temperature record from Barrow, Alaska is one of the most widely used datasets for demonstrating Arctic warming. Yet, recent evidence suggests that there is a substantial heat island in the village (Hinkel et al., 2003; 2004). NWS records in downtown and the National Oceanic and Atmospheric Administration's Climate Monitoring and Diagnostics Lab (CMDL) data from several miles upwind of the village show a distinct difference between urban and rural temperatures. To demonstrate evidence of either a heat island or climate warming, a number of factors must first be examined at each of these sites. These factors are similar to those at most climate-monitoring sites in less remote parts of the world. In the 25 years since the beginning of the CMDL record, Barrow has grown from 2200 to 4600 residents. Instrumentation changes were implemented at both sites. A station move took place. Coastal influences are also large near Barrow and distance from the coast may be an influence. Unraveling the impacts of these considerations on the temperature differences between the NWS and CMDL sites is challenging. While Arctic climate change is a pressing issue and few temperature records are available, care must be taken to ensure that unbiased data are used in analysis. As urban development increases in Arctic regions, information on urban-rural temperature interactions may become more vital, particularly given the possibility of increasing temperatures accompanying climate change.

  9. Increased temperature variation poses a greater risk to species than climate warming.

    Science.gov (United States)

    Vasseur, David A; DeLong, John P; Gilbert, Benjamin; Greig, Hamish S; Harley, Christopher D G; McCann, Kevin S; Savage, Van; Tunney, Tyler D; O'Connor, Mary I

    2014-03-22

    Increases in the frequency, severity and duration of temperature extremes are anticipated in the near future. Although recent work suggests that changes in temperature variation will have disproportionately greater effects on species than changes to the mean, much of climate change research in ecology has focused on the impacts of mean temperature change. Here, we couple fine-grained climate projections (2050-2059) to thermal performance data from 38 ectothermic invertebrate species and contrast projections with those of a simple model. We show that projections based on mean temperature change alone differ substantially from those incorporating changes to the variation, and to the mean and variation in concert. Although most species show increases in performance at greater mean temperatures, the effect of mean and variance change together yields a range of responses, with temperate species at greatest risk of performance declines. Our work highlights the importance of using fine-grained temporal data to incorporate the full extent of temperature variation when assessing and projecting performance.

  10. Detecting phenology change in the mayfly Ephemera danica in response to water temperature variations

    Science.gov (United States)

    Johnson, Matthew; Everall, Nicholas; Wilby, Robert

    2014-05-01

    Water temperature is critical to aquatic life. Rising river temperatures under climate change are expected to affect the phenology (i.e. timing of life events) of aquatic insects, including Ephemera danica which is a large burrowing mayfly that is widespread throughout Europe. To assess the temporal and spatial variability in mayfly emergence, E. danica were monitored at two reaches in the River Dove, English Peak District over the period 2007 to 2013. Inter-annual variations in Growing Degree Days (GDDs) were modelled for an upstream site with intermittent spring flows supplementing main channel flow (Beresford Dale) and a downstream site dominated by near constant discharges of cool groundwater (Dovedale). The emergence cycle of E. danica was strongly related to GDDs at each site. E. danica usually remains in an aquatic larval stage for two years before emerging in its adult, terrestrial form. However, after particularly warm summers in Beresford Dale, E. danica was recorded to emerge after only one year in its aquatic form. Following the particularly wet/cold year of 2012, E. danica began to revert back to a bi-annual cycle. In Dovedale, an average of 374 fewer GDDs were accumulated in comparison to Beresford Dale. As a result, E. danica maintained a two-year growth cycle throughout the monitoring period despite the phenology changes observed 8 km upstream at Beresford. Changes to insect phenology are significant because populations with a one-year cycle are potentially more vulnerable to adverse weather when the majority of the population is in terrestrial form. Also, altering the growth, development and size of insects affects reproductive success with implications for population dynamics. Conventional monitoring of both water temperature and invertebrates as used by regulatory authorities in the UK, did not identify the changes in insect phenology or the association between phenology and water temperature. Data from the present study suggest that habitats

  11. Study about geomagnetic variations from data recorded at Surlari Geomagnetic Observatory

    Science.gov (United States)

    Asimopolos, Laurentiu; Asimopolos, Natalia-Silvia; Sandulescu, Agata Monica; Niculici, Eugen

    2013-04-01

    This paper presents statistical and spectral analysis of data from Surlari Geomagnetic Observatory that contributing to study of geomagnetic variations. Thus were highlighted, for long series of records over several solar cycles, periodicities of 22 years and 11 years. Following the same procedures for medium recording series (multi-annual) have highlighted annual, seasonal and monthly periodicities. For shorter data series, we highlighted diurnal, semidiurnal, 8 hours and even lower periodicities. For very short series with a high sample rate and for few magnetotellurics records, we highlight different types of pulsations (Pc2 - Pc5 and Pi 2). Geomagnetic signals are the convolution product of the atomic stationary signals mono-frequential of different amplitudes associated to phenomena with a very broad band of periodicities and nondeterministic signals associated with geomagnetic disturbances and non-periodic phenomena. Among analysis processes used for discrete series of geomagnetic data with different lengths and sampling rates, can conclude the following: Moving average works as a low pass filter in frequency or high pass in time. By eliminating high frequency components (depending on mobile window size used) can be studied preferential periodicities greater than a given value. Signal linearization (using least squares) provides information on linear trend of the entire series analyzed. Thus, for the very long data series (several decades) we extracted the secular variation slope for each geomagnetic component, separately. The numeric derivative of signal versus time proved to be a very reliable indicator for geomagnetic disturbed periods. Thus, the derivative value may be increased by several orders of magnitude during periods of agitation in comparisons to calm periods. The correlation factor shows significant increases when between two time series a causal relationship exists. Variation of the correlation factor, calculated for a mobile window containing k

  12. Quantitative Estimation of Temperature Variations in Plantar Angiosomes: A Study Case for Diabetic Foot

    OpenAIRE

    Peregrina-Barreto, H.; Morales-Hernandez, L. A.; Rangel-Magdaleno, J. J.; Avina-Cervantes, J. G.; Ramirez-Cortes, J. M.; Morales-Caporal, R.

    2014-01-01

    Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regard...

  13. Time-Dependent Behavior of Shrinkage Strain for Early Age Concrete Affected by Temperature Variation

    Directory of Open Access Journals (Sweden)

    Yu Qin

    2017-01-01

    Full Text Available Shrinkage has been proven to be an important property of early age concrete. The shrinkage strain leads to inherent engineering problems, such as cracking and loss of prestress. Atmospheric temperature is an important factor in shrinkage strain. However, current research does not provide much attention to the effect of atmospheric temperature on shrinkage of early age concrete. In this paper, a laboratory study was undertaken to present the time-dependent shrinkage of early age concrete under temperature variation. A newly developed Material Deformation Tester (MDT, which can simulate consecutive variation of atmospheric temperature, was used to collect the shrinkage strain of specimens and temperature data. A numerical model was established to describe the thermoelastic strain of a specimen. The results show that (1 there are several sharp shrinkages up to 600 μ for early age concrete in the first 3 days; (2 the absolute value of shrinkage strain is larger than thermal strain; and (3 the difference of shrinkage strain under temperature variation or constant temperature is up to 500 μ.

  14. Coherent millennial-scale patterns in U37k‧ and TEX86H temperature records during the penultimate interglacial-to-glacial cycle in the western Mediterranean

    Science.gov (United States)

    Huguet, Carme; Martrat, Belen; Grimalt, Joan O.; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2011-06-01

    The TEX86H temperature proxy is a relatively new proxy based on crenarchaeotal lipids and has rarely been applied together with other temperature proxies. In this study, we applied the TEX86H on a sediment core from the Alboran Sea (western Mediterranean, core ODP-977A) covering the penultimate climate cycle, that is, from 244 to 130 ka, and compared this with previously published sea surface temperatures derived from the U37k' of alkenones of haptophyta and Mg/Ca records of planktonic foraminifera. The TEX86H temperature record shows remarkably similar stadial-interstadial patterns and abrupt temperature changes to those observed with the U37k' palaeothermometer. Absolute TEX86H temperature estimates are generally higher than those of U37k', though this difference (crenarchaeota and haptophyta experienced similar temperature variations. During occasional events (<5% of the analyzed time span), however, the TEX86H exhibits considerably higher absolute temperature estimates than the U37k'. Comparison with Mg/Ca records of planktonic foraminifera as well as other Mediterranean TEX86 and U37k' records suggests that part of this divergence may be attributed to seasonal differences, that is, with TEX86H reflecting mainly the warm summer season while U37k' would show annual mean. Biases in the global calibration of both proxies or specific biases in the Mediterranean are an alternative, though less likely, explanation. Despite differences between absolute TEX86H and U37k' temperatures, the correlation between the two proxies (r2 = 0.59, 95% significance) provides support for the occurrence of abrupt temperature variations in the western Mediterranean during the penultimate interglacial-to-glacial cycle.

  15. Study on Impact of Variation of Carbon Monoxide Concentration to Air Temperature at Simpang Lima, Banda Aceh

    Directory of Open Access Journals (Sweden)

    Rahimi .

    2012-09-01

    Full Text Available Studies on impact of variation of carbon monoxide concentration to air temperature have been conducted at Simpang Lima, Banda Aceh. Objectives of this research are to determine the level of emissions of carbon monoxide from motor vehicles, to study the fluctuations of air temperature in the area, and to analyze the impact of increasing carbon monoxide concentration to the air temperature at Simpang Lima Banda Aceh during 2010. Concentration of carbon monoxide and air temperature were recorded by Air Quality Monitoring System (AQMS device installed at Simpang Lima Banda Aceh. The result shows that carbon monoxide concentration increases as well as number of vehicles passing the area. Change of the concentration in the air is also influenced by temperature variability in the research area. For the temperature, beside affected by carbon monoxide concentrations are also influenced by weather factors such as solar radiation, wind speed and precipitation. However, levels of carbon monoxide concentration at Simpang Lima, Banda Aceh are considerably safe for the environment, i. e. less than 100 ppm.

  16. Strong lateral variation of ground temperature revealed by a large network of boreholes in the Slave Geological Province of Canada

    Science.gov (United States)

    Gruber, Stephan; Riddick, Julia; Brown, Nick; Karunaratne, Kumari; Kokelj, Steve V.

    2017-04-01

    The Slave Geological Province is a key region in the Canadian North. Its tundra areas form a large and resource-rich landscape in which comparably few systematic permafrost observations exist. Because the region contains layers of ice-rich till, the ground is susceptible to subsidence during thaw. Consequently, possible impacts of permafrost thawing on infrastructure and the natural environment motivate baseline investigations and simulation studies. In this context, the spatial variation of ground temperatures is relevant: How well can we extrapolate from one or few locations of observation? How well can we describe permafrost characteristics with coarse-grid (e.g., 50 km) models assuming relatively homogenous conditions? In July 2015, an observation network of more than 40 plots was installed to monitor ground thermal regime and to detect surface subsidence. Plots are within few tens of meters to few tens of kilometers from each other and were chosen to represent a distinct combination of surficial geology, vegetation, drainage conditions, and snow accumulation. In each plot (15 m x 15 m), temperatures are recorded in a borehole as well as about 10 cm deep at four locations. Data on surface and subsurface properties has been recorded as well. In September 2016, data was downloaded from the loggers and the conditions of the instruments were described. This contribution presents the first year of temperature data. In the annual averages, it reveals more than 7°C lateral variation between plots as well as within-plot variations of more than 2.5°C. This underscores the need for carefully designing measurement campaigns and methods when aiming to test coarse-scale permafrost simulations, even in gentle topography. The data resulting from this observational network will be made available publicly in the near future.

  17. SNOW TEMPERATURE MEASUREMENTS AT VOSTOK STATION FROM AN AUTONOMOUS RECORDING SYSTEM (TAUTO: PRELIMINARY RESULTS FROM THE FIRST YEAR OPERATION

    Directory of Open Access Journals (Sweden)

    E. Lefebvre

    2012-01-01

    Full Text Available Temperature gradients in the upper layers of the snow pack are of importance for studying the emissivity properties of the snow surface with respect to microwaves used in remote sensing as well as for the heat and mass transfer in snow thickness. Gradients drive the initial snow microstructure metamorphisms that probably influence the firn properties in regard to air molecules fractionation and the air bubble enclosure process at close-off depths. As a contribution to investigation of these problems and following J.-M. Barnola initiative, we developed an autonomous recording system to monitor the temperature of the upper layers of the snow pack. The instrument was built to be autonomous and to be continuously operating within environmental conditions of the Antarctic plateau and the polar night. The apparatus which monitors temperature from the first 10 mof snow by 15 sensors of a «temperature grape» was set at Vostok station during 55th Russian Antarctic Expedition within the frame of the French Russian collaboration (GDRI Vostok. From the available hourly measurements over the first year, we present preliminary results on the thermal diffusive properties of the snow pack as well as some character of the temperature variations on the Antarctic plateau.

  18. Variational calculation of the slip coefficient and the temperature jump for arbitrary gas-surface interactions

    Science.gov (United States)

    Cercignani, C.; Lampis, M.

    The aim of this paper is to compute the slip and temperature jump coefficients for a rarefied gas having an arbitrary interaction with a solid surface by means of a variational technique. This problem was considered by Klinc and Kuscer (1972), using a variational principle for the integral version of the Boltzmann equation. In this paper a variational method is used for the integrodifferential version of the Boltzmann equation, proposed by Cercignani (1969). With the simplest trial functions, general formulas are obtained that look simpler than those proposed by Klinc and Kuscer, but reduce to the latter when all of the accommodation coefficients are equal. Numerical values compare favorably with existing numerical solutions.

  19. Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa

    Science.gov (United States)

    The Hg0 time series recorded at the Mauna Loa Observatory (MLO) in Hawaii between 2002 and 2009 has been analyzed using Empirical Mode Decomposition. This technique has been used in numerous contexts in order to identify periodical variations in time series data. The periodicitie...

  20. Identification of the driving forces of climate change using the longest instrumental temperature record

    OpenAIRE

    Wang, Geli; Yang, Peicai; Zhou, Xiuji

    2017-01-01

    The identification of causal effects is a fundamental problem in climate change research. Here, a new perspective on climate change causality is presented using the central England temperature (CET) dataset, the longest instrumental temperature record, and a combination of slow feature analysis and wavelet analysis. The driving forces of climate change were investigated and the results showed two independent degrees of freedom ?a 3.36-year cycle and a 22.6-year cycle, which seem to be connect...

  1. Finite-temperature time-dependent variation with multiple Davydov states

    Science.gov (United States)

    Wang, Lu; Fujihashi, Yuta; Chen, Lipeng; Zhao, Yang

    2017-03-01

    The Dirac-Frenkel time-dependent variational approach with Davydov Ansätze is a sophisticated, yet efficient technique to obtain an accurate solution to many-body Schrödinger equations for energy and charge transfer dynamics in molecular aggregates and light-harvesting complexes. We extend this variational approach to finite temperature dynamics of the spin-boson model by adopting a Monte Carlo importance sampling method. In order to demonstrate the applicability of this approach, we compare calculated real-time quantum dynamics of the spin-boson model with that from numerically exact iterative quasiadiabatic propagator path integral (QUAPI) technique. The comparison shows that our variational approach with the single Davydov Ansätze is in excellent agreement with the QUAPI method at high temperatures, while the two differ at low temperatures. Accuracy in dynamics calculations employing a multitude of Davydov trial states is found to improve substantially over the single Davydov Ansatz, especially at low temperatures. At a moderate computational cost, our variational approach with the multiple Davydov Ansatz is shown to provide accurate spin-boson dynamics over a wide range of temperatures and bath spectral densities.

  2. Temperature variations in a housing of the semi-arid region of Djelfa (Algeria)

    Energy Technology Data Exchange (ETDEWEB)

    Ettoumi, F.Y.; Adane, A.E.H. [Universite de Sciences et Technologie Houari Boumediene, Faculte de Genie Electrique, Alger (Algeria); Messen, N. [C.N.R.B.-BP, Wilaya de Djelfa (Algeria); Sauvageot, H. [Universite Paul Sabatier, Toulouse (France). Lab. d' Aerologie

    2002-03-01

    Temperature variations are analysed for two areas of Algeria, lying in a semi-arid region and near the West Coast, respectively, the Djelfa and Oran areas. This analysis mainly consists in computing the temperature deviations with respect to the reference levels of 18{sup o}C and 25{sup o}C. Their time variations are then studied. When summing the temperature deviations per month, the amount of energy, expressed in degree hour for each month of the year, necessary to heat and cool the houses during cold weather and hot periods, respectively, is obtained. An economic study of construction material efficiency is associated with the computation of the temperature deviations and applied to housing in semi-arid regions. It is shown that cheap traditional materials having greater thermal inertia can advantageously be used for housing constructions in these regions.(author)

  3. Spatial Variation of Temperature and Precipitation in Bhutan and Links to Vegetation and Land Coveropen access

    DEFF Research Database (Denmark)

    Dorji, Ugyen; Olesen, Jørgen Eivind; Bøcher, Peder Klith

    2016-01-01

    Bhutan, located in the Himalayas in the South Asian monsoon region, has extremely high variation in elevation, climatic conditions, and land cover despite its small geographical area, as well as great biodiversity. This paper provides the first comprehensive description of climatic conditions...... that temperatures changed by about 0.5°C for every 100 m of change in elevation, with lapse rates being highest in February, March, and November and lowest from June to August. The lapse rate was highest for minimum temperatures and lowest for maximum temperatures, with the greatest difference during winter....... The spatial distribution of precipitation was mainly controlled by latitude, having a quadratic relationship, with the highest rates in the southern foothills of the Himalayan range and the lowest at midlatitudes. The land cover is affected by topography and local climate, with variations in temperature being...

  4. Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators.

    Directory of Open Access Journals (Sweden)

    Dominiek Vangansbeke

    Full Text Available The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae. We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen's inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes.

  5. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    Science.gov (United States)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  6. Seasonal Variations in Temperature, Sality and Density In- and off Ise Bay

    OpenAIRE

    Sekine, Yoshihiko; Mizutani, Hideharu; Motoya, Takayuki; 関根, 義彦; 水谷, 秀治; 本谷, 隆行

    1992-01-01

    Seasonal variations in temperature, salinity and.density in- and off Ise Bay are examined by statistical data analyses. The observational data during the period from 1985 to 1989 obtained by Aichi Fisheries Research Institute and by Fisheries Research Institute of Mie are used to present the monthly mean horizontal maps and those of their standard deviations. It is pointed out that horizontal difference in the sea surface temperature (SST) between in and out of Ise Bay is largest in spring an...

  7. The mastery of temperature changes; La maitrise des variations de temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Nassau, St. [Danfoss, 78 - Trappes (France)

    1998-10-01

    Temperature changes in building supplied by a commercial cold production installation remain an unsolved problem. A solution could be found with the use of electronic modulating thermostats. This paper presents a comparative evaluation of such a system with a classical differential thermostat. (J.S.)

  8. Monitoring and modeling temperature variations inside silage stacks using novel wireless sensor networks

    DEFF Research Database (Denmark)

    Green, O.; Nadimi, E.S.; Blanes-Vidal, V.

    2009-01-01

    By monitoring silage temperature at different locations inside silage stacks, it is possible to detect any significant increases in temperature occurring during silage decomposition. The objectives of this study were: (1) to develop novel noninvasive wireless sensor nodes for measuring...... the temperature inside silage stacks; (2) to design a suitable sensor protection housing that prevents physical and chemical damage to the sensor: and (3) to mathematically model temperature variations inside a silage stack, using system identification techniques. The designed wireless nodes were used to monitor...... temperatures in a full-sized silage stack over 53 days. Results showed that the wireless sensor nodes accurately monitored the temperature inside the silage stack at depths of 25 and 50cm and reliably transmitted the measured data through the network; between 98.9% and 99.4% of the packets disseminated from...

  9. Variation of the channel temperature in the transmission of lightning leader

    Science.gov (United States)

    Chang, Xuan; Yuan, Ping; Cen, Jianyong; Wang, Xuejuan

    2017-06-01

    According to the time-resolved spectra of the lightning stepped leader and dart leader processes, the channel temperature, its evolution characteristics with time and the variation along the channel height in the transmission process were analyzed. The results show that the stepped leader tip has a slightly higher temperature than the trailing end, which should be caused by a large amount of electric charges on the leader tip. In addition, both temperature and brightness are enhanced at the position of the channel node. The dart leader has a higher channel temperature than the stepped leader but a lower temperature than the return stroke. Meanwhile, the channel temperature of the dart leader obviously increases when the dart leader propagates to the ground.

  10. Effect of short-term regulated temperature variations on the swimming economy of Atlantic salmon smolts.

    Science.gov (United States)

    Alexandre, C M; Palstra, A P

    2017-01-01

    Migratory species travelling long distances between habitats to spawn or feed are well adapted to optimize their swimming economy. However, human activities, such as river regulation, represent potential threats to fish migration by changing environmental parameters that will have impact on their metabolism. The main objective of this study was to evaluate the changes in the swimming energetics of a salmonid species, Atlantic salmon (Salmo salar L.), caused by short-term temperature variations that usually result from the operation of hydroelectrical dams. Intermittent flow respirometry in swim tunnels allows to obtain high resolution data on oxygen consumption of swimming fish which can reflect aerobic and anaerobic metabolism. This method was used to compare the metabolic rates of oxygen consumption before, during and after sudden thermal change. Control (no temperature variation) and experimental (temperature variation of approximately 4°C in 1 h) swimming trials were conducted to achieve the following objectives: (i) quantify the variations in oxygen consumption associated with abrupt temperature decrease, and (ii) assess if the tested fish return quickly to initial oxygen consumption rates. Main results revealed that Atlantic salmon smolts show a strong response to sudden temperature variation, significantly reducing the oxygen consumption rate up to a seven-fold change. Fish quickly returned to initial swimming costs shortly after reestablishment of temperature values. Results from this study can be used to evaluate the species-specific effects of the applied operation modes by hydroelectrical dams and to increase the success of conservation and management actions directed to fish species inhabiting regulated rivers.

  11. Daytime ozone and temperature variations in the mesosphere: A comparison between SABER observations and HAMMONIA model

    Energy Technology Data Exchange (ETDEWEB)

    Dikty, Sebastian; Weber, Mark; Savigny, Christian von [Institute of Environmental Physics, Bremen (Germany); Schmidt, Hauke [Max Planck Institute for Meteorology, Hamburg (Germany); Mlynczak, Martin [Langley Research Center, NASA (United States)

    2010-07-01

    The scope of this paper is to investigate the latest version 1.07 SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) tropical ozone and temperature data with respect to daytime variations in the upper mesosphere. For a better understanding of the processes involved we compare these daytime variations to the output of the three-dimensional general circulation and chemistry model HAMMONIA (Hamburg Model of the Neutral and Ionized Atmosphere). The results show good agreement for ozone. The amplitude of daytime variations is in both cases approximately 60 % of the daytime mean. During equinox the daytime maximum ozone abundance is for both, the observations and the model, higher than during solstice, especially above 80 km. We also use the HAMMONIA output of daytime variation patterns of several other different trace gas species, e.g., water vapor and atomic oxygen, to discuss the daytime pattern in ozone. In contrast to ozone, temperature data show little daytime variations between 65 and 90 km and their amplitudes are on the order of less than 1.5 %. In addition, SABER and HAMMONIA temperatures show significant differences above 80 km.

  12. Temperature variations in Greenland from 10 to 110 kyr b2k derived from the NGRIP ice core

    Science.gov (United States)

    Kindler, Philippe; Leuenberger, Markus; Landais, Amaelle; Guillevic, Myriam

    2013-04-01

    During the last ice age dramatic temperature variations of up to 16 °C took place in Greenland which are now known as Dansgaard-Oeschger-events (DO-events). They most probably originate from the North Atlantic oceanic and atmospheric circulation system and are characterised by an abrupt warming within decades followed by a gradual cooling over hundreds to thousands of years. We have determined local temperature variations for DO-event 1 to 25 in Greenland based on δ15N measurements from the NorthGRIP ice core, corresponding to the period from 10 to 110 kyr b2k. The record is a composite of measurements from two laboratories, Laboratoire des Sciences du Climat et de l'Environnement, Paris (DO 18 to 25) and the Climate and Environmental Physics Division of the Physics Institute of the University of Bern (DO 1 to 17) with new measurements from the beginning of the Holocene to DO 8. Temperature variations were reconstructed by reproducing the measured 15N/14N ratio of air enclosed in ice bubbles by the firn densification and heat diffusion model from Schwander. The reconstruction show temperature amplitudes for the DO-events ranging from 5 to 16 °C, thereby the corresponding rates of change can exceed 0.5 °C/decade. In order get an agreement between measured δ15N, Δdepth and Δage values with their modelled analogues, a lower accumulation rate than the one associated with the used ss09sea06bm1 time scale had to be assumed. We had to reduce the accumulation rate time dependently by 0 to nearly 40% with a mean reduction over the whole time period of 16%. With these adjustments both the Δdepth and the Δage values agree between model and measurements.

  13. Variation in Yield Responses to Elevated CO2 and a Brief High Temperature Treatment in Quinoa

    Science.gov (United States)

    Bunce, James A.

    2017-01-01

    Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient”) and 600 (“elevated”) μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control”) temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures) for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control) or increased (1.70 × control) seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined. PMID:28678208

  14. Variation in Yield Responses to Elevated CO2 and a Brief High Temperature Treatment in Quinoa

    Directory of Open Access Journals (Sweden)

    James A. Bunce

    2017-07-01

    Full Text Available Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient” and 600 (“elevated” μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control” temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control or increased (1.70 × control seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined.

  15. Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization over Temperature Variation

    Science.gov (United States)

    2016-07-01

    ARL-TR-7718 ● JULY 2016 US Army Research Laboratory Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale...JULY 2016 US Army Research Laboratory Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization...System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization over Temperature Variation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  16. RF transconductor linearization technique robust to process, voltage and temperature variations

    NARCIS (Netherlands)

    Kundur Subramaniyan, H.; Klumperink, Eric A.M.; Nauta, Bram; Venkatesh, Srinivasan; Kiaei, Ali

    2014-01-01

    A new reconfigurable linearized low noise transconductance amplifier (LNTA) design for a software-defined radio receiver is presented. The transconductor design aims at realizing high linearity at RF in a way that is robust for Process, Voltage and Temperature variations. It exploits resistive

  17. Solar flux variation of the electron temperature morning overshoot in the equatorial F region

    DEFF Research Database (Denmark)

    Stolle, Claudia; Liu, H.; Truhlik, V.

    2011-01-01

    Using 8 years of CHAMP satellite observations of the equatorial electron temperature, T-e, we investigate its behavior during the morning overshoot and at ionospheric altitudes below 450 km including its variation with solar activity. The morning T-e has a maximum at the dip equator and decreases...

  18. Temporal variation in temperature determines disease spread and maintenance in Paramecium microcosm populations.

    Science.gov (United States)

    Duncan, Alison B; Fellous, Simon; Kaltz, Oliver

    2011-11-22

    The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host-parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Infected and uninfected populations of two P. caudatum genotypes were created and four constant temperature treatments (26°C, 28°C, 30°C and 32°C) compared with four variable treatments with the same mean temperatures. Variable temperature treatments were achieved by alternating populations between permissive (23°C) and restrictive (35°C) conditions daily over 30 days. Variable conditions and high temperatures caused greater declines in Paramecium populations, greater fluctuations in population size and higher incidence of extinction. The additional effect of parasite infection was additive and enhanced the negative effects of the variable environment and higher temperatures by up to 50 per cent. The variable environment and high temperatures also caused a decrease in parasite prevalence (up to 40%) and an increase in extinction (absence of detection) (up to 30%). The host genotypes responded similarly to the different environmental stresses and their effect on parasite traits were generally in the same direction. This work provides, to our knowledge, the first experimental demonstration that epidemiological dynamics are influenced by environmental variation. We also emphasize the need to consider environmental variance, as well as means, when trying to understand, or predict population dynamics or range.

  19. Online Junction Temperature Cycle Recording of an IGBT Power Module in a Hybrid Car

    Directory of Open Access Journals (Sweden)

    Marco Denk

    2015-01-01

    Full Text Available The accuracy of the lifetime calculation approach of IGBT power modules used in hybrid-electric powertrains suffers greatly from the inaccurate knowledge of application typical load-profiles. To verify the theoretical load-profiles with data from the field this paper presents a concept to record all junction temperature cycles of an IGBT power module during its operation in a test vehicle. For this purpose the IGBT junction temperature is measured with a modified gate driver that determines the temperature sensitive IGBT internal gate resistor by superimposing the negative gate voltage with a high-frequency identification signal. An integrated control unit manages the TJ measurement during the regular switching operation, the exchange of data with the system controller, and the automatic calibration of the sensor system. To calculate and store temperature cycles on a microcontroller an online Rainflow counting algorithm was developed. The special feature of this algorithm is a very accurate extraction of lifetime relevant information with a significantly reduced calculation and storage effort. Until now the recording concept could be realized and tested within a laboratory voltage source inverter. Currently the IGBT driver with integrated junction temperature measurement and the online cycle recording algorithm is integrated in the voltage source inverter of first test vehicles. Such research will provide representative load-profiles to verify and optimize the theoretical load-profiles used in today’s lifetime calculation.

  20. The variation of the dust temperature within late-type spiral galaxies

    Science.gov (United States)

    Evans, Rhodri H.

    1994-01-01

    We use high resolution (HiRes) 60 and 100 micron data to investigate the variation of the dust temperature in a sample of 4 late-type spiral galaxies. We have investigated the radial variation of the azimuthally averaged 60 and 100 micron surface brightness profiles to see how the dust temperature (or, more correctly, the relative strength of the two components) varies as a function of radius within the galaxies. We find strong evidence for a decrease in the dust temperature (or an increase in the relative contribution of the 100 micron flux compared to the 60 micron flux) as a function of radius. We discuss these results in the light of the continuing debate as to whether massive star formation or the general interstellar radiation field is the major heating source of the dust.

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

    Science.gov (United States)

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

    2016-08-01

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

  2. Millennial and sub-millennial scale climatic variations recorded in polar ice cores over the last glacial period

    Directory of Open Access Journals (Sweden)

    E. Capron

    2010-06-01

    Full Text Available Since its discovery in Greenland ice cores, the millennial scale climatic variability of the last glacial period has been increasingly documented at all latitudes with studies focusing mainly on Marine Isotopic Stage 3 (MIS 3; 28–60 thousand of years before present, hereafter ka and characterized by short Dansgaard-Oeschger (DO events. Recent and new results obtained on the EPICA and NorthGRIP ice cores now precisely describe the rapid variations of Antarctic and Greenland temperature during MIS 5 (73.5–123 ka, a time period corresponding to relatively high sea level. The results display a succession of abrupt events associated with long Greenland InterStadial phases (GIS enabling us to highlight a sub-millennial scale climatic variability depicted by (i short-lived and abrupt warming events preceding some GIS (precursor-type events and (ii abrupt warming events at the end of some GIS (rebound-type events. The occurrence of these sub-millennial scale events is suggested to be driven by the insolation at high northern latitudes together with the internal forcing of ice sheets. Thanks to a recent NorthGRIP-EPICA Dronning Maud Land (EDML common timescale over MIS 5, the bipolar sequence of climatic events can be established at millennial to sub-millennial timescale. This shows that for extraordinary long stadial durations the accompanying Antarctic warming amplitude cannot be described by a simple linear relationship between the two as expected from the bipolar seesaw concept. We also show that when ice sheets are extensive, Antarctica does not necessarily warm during the whole GS as the thermal bipolar seesaw model would predict, questioning the Greenland ice core temperature records as a proxy for AMOC changes throughout the glacial period.

  3. Monitoring and Modeling Temperature Variations Inside Silage Stack Using Novel Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Green, Ole; Shahrak Nadimi, Esmaeil; Blanes-Vidal, Victoria

    2009-01-01

    of withstanding the high loads that occurred during ensiling, storage, and feed-out. Mathematical models estimating the relations between the silage temperatures (at depths of 25 and 50 cm) and air and soil temperatures were obtained. Black-box modeling using the prediction error method (PEM) was selected...... the temperature inside silage stacks; (2) to design a suitable sensor protection housing that prevents physical and chemical damage to the sensor; and (3) to mathematically model temperature variations inside a silage stack, using system identification techniques. The designed wireless nodes were used to monitor...... as the identification method. Among different black-box models such as ARX, ARMAX, Output Error (OE), and Box-Jenkins (BJ), with different model orders, a third-order Box-Jenkins model structure gave the best performance in terms of prediction accuracy. The success rate of the models proposed for silage temperature...

  4. Decadal/interdecadal variations of the ocean temperature and its impacts on climate

    Science.gov (United States)

    Li, Chongyin; Zhou, Wen; Jia, Xiaolong; Wang, Xin

    2006-12-01

    Decadal/interdecadal climate variability is an important research focus of the CLIVAR Program and has been paid more attention. Over recent years, a lot of studies in relation to interdecadal climate variations have been also completed by Chinese scientists. This paper presents an overview of some advances in the study of decadal/interdecadal variations of the ocean temperature and its climate impacts, which includes interdecadal climate variability in China, the interdecadal modes of sea surface temperature (SST) anomalies in the North Pacific, and in particular, the impacts of interdecadal SST variations on the Asian monsoon rainfall. As summarized in this paper, some results have been achieved by using climate diagnostic studies of historical climatic datasets. Two fundamental interdecadal SST variability modes (7 10-years mode and 25 35-years mode) have been identified over the North Pacific associated with different anomalous patterns of atmospheric circulation. The southern Indian Ocean dipole (SIOD) shows a major feature of interdecadal variation, with a positive (negative) phase favoring a weakened (enhanced) Asian summer monsoon in the following summer. It is also found that the China monsoon rainfall exhibits interdecadal variations with more wet (dry) monsoon years in the Yangtze River (South China and North China) before 1976, but vice versa after 1976. The weakened relationship between the Indian summer rainfall and ENSO is a feature of interdecadal variations, suggesting an important role of the interdecadal variation of the SIOD in the climate over the south Asia and southeast Asia. In addition, evidence indicates that the climate shift in the 1960s may be related to the anomalies of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO). Overall, the present research has improved our understanding of the decadal/interdecadal variations of SST and their impacts on the Asian monsoon rainfall. However, the research also highlights a

  5. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Science.gov (United States)

    Lüdecke, H.-J.; Hempelmann, A.; Weiss, C. O.

    2013-02-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detrended fluctuation analysis (DFA). For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar) and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  6. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Directory of Open Access Journals (Sweden)

    H.-J. Lüdecke

    2013-02-01

    Full Text Available The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT, wavelets, and the detrended fluctuation analysis (DFA. For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  7. Long-Term Instrumental and Reconstructed Temperature Records Contradict Anthropogenic Global Warming

    CERN Document Server

    Lüdecke, Horst-Joachim

    2011-01-01

    Monthly instrumental temperature records from 5 stations in the northern hemisphere are analyzed, each of which is local and over 200 years in length, as well as two reconstructed long-range yearly records - from a stalagmite and from tree rings that are about 2000 years long. In the instrumental records, the steepest 100-year temperature fall happened in the 19th century and the steepest rise in the 20th century, both events being of about the same magnitude. Evaluation by the detrended fluctuation analysis (DFA) yields Hurst exponents that are in good agreement with the literature. DFA, Monte Carlo simulations, and synthetic records reveal that both 100-year events were caused by external trends. In contrast to this, the reconstructed records show stronger 100-year rises and falls as quite common during the last 2000 years. These results contradict the hypothesis of an unusual (anthropogenic) global warming during the 20th century. As a hypothesis, the sun's magnetic field, which is correlated with sunspot ...

  8. Frequency of extreme daily temperatures (HadEX2) over Eurasia documented in a northern Red Sea coral oxygen isotope record during the last century

    Science.gov (United States)

    Ionita-Scholz, Monica; Felis, Thomas; Rimbu, Norel; Lohmann, Gerrit

    2017-04-01

    The potential of a bimonthly-resolved northern Red Sea coral δ18O record as an archive for the occurrence of extreme daily temperature phenomena over Eurasia during Northern Hemisphere winter is investigated for the 1901-1995 period using extreme indices provided by the HadEX2 dataset (e.g., frost days, ice days, cold nights and cold days). The coral δ18O record reflects a combined signal of temperature and salinity variations in the surface waters of the northern Red Sea, and has been previously shown to provide a proxy for atmospheric circulation changes over the Northern Hemisphere mid-latitudes at interannual to decadal time scales. Here we show, by applying composite analysis, that cooler/more arid (warmer/less arid) winter conditions in the northern Red Sea region, indicated by positive (negative) coral δ18O anomalies (January-February), are related to a strong (weak) Northern Hemisphere polar vortex and, as a consequence, to a decreased (increased) number of days characterized by very cold temperatures and frost over Scandinavia and Central Europe. This situation is associated with an increased (decreased) number of days characterized by very cold temperatures and frost over the Balkan region. The occurrence of these daily temperature extremes is modulated by the frequency of atmospheric blocking over the British Isles and Central Europe, and a shift in the direction of the North Atlantic storm tracks. Importantly, coral records provide a bimonthly to monthly resolution, compared to other high-resolution proxy records which have either an annual resolution (e.g., ice cores, varved sediments) or an annual resolution with a signal that is biased towards a specific season that in most cases is not winter (e.g., tree rings). We argue that bimonthly-resolved northern Red Sea coral δ18O records provide an archive of interannual to decadal variations in the occurrence of extreme daily temperature events over wintertime Eurasia prior to the start of instrumental

  9. Ontogenetic variations in flush development are indicative of low temperature tolerance in Hevea brasiliensis clones

    Directory of Open Access Journals (Sweden)

    K.K. Vinod

    2013-12-01

    Full Text Available Para rubber (Hevea brasiliensis trees are naturally adapted to the Amazonian tropical climate. In India rubber trees are traditionally cultivated in the warm humid tropics of the south. Northeast India is a non-traditional area for rubber cultivation. A major limiting factor on tree growth in the northeast region is stress due to low temperature. Being a deciduous tree, rubber trees exhibit annual natural defoliation prior to the winter season, and ensuing new leaf growth usually coincides with the low temperature period. Flushing behaviour of trees during this period provides an opportunity to assess their winter hardiness. A study was carried out on five clones, RRIM 600, SCATC 93/114, GT 1, PB 5/51 and Haiken 1, to evaluate phenological behaviour of leaf growth during the period of low temperature stress. Trees were monitored for expansion of leaf area, internode length, petiole length and development of chlorophyll. Wide variation was observed among these clones for all the traits. SCATC 93/114 was better adapted for low temperature stress as this clone was found to have faster expansion of leaf area and better chlorophyll development, followed by Haiken 1. PB 5/51 was found to show poor performance during low temperature. Haiken 1 and PB 5/51 also exhibited better relative growth rate during winter months confirming their low temperature tolerance. Ontogenetic variations in leaf development are good indicators of assessing inherent cold tolerance in Hevea clones.

  10. Temperature variation at the external root surface during 980-nm diode laser irradiation in the root canal.

    Science.gov (United States)

    Alfredo, E; Marchesan, M A; Sousa-Neto, M D; Brugnera-Júnior, A; Silva-Sousa, Y T C

    2008-07-01

    To assess the temperature variation in the cervical, middle and apical thirds of root external wall, caused by 980-nm diode laser irradiation with different parameters. The roots of 90 canines, had their canals instrumented and were randomly distributed into 3 groups (n=30) according to the laser potency (1.5 W, 3.0 W and 5.0 W). Each group was subdivided into 3 (n=10) according to the frequency (CM, 100 Hz and 1000 Hz), and each subgroup divided into 2 (n=5): dried canal or filled with distilled water. The maximum temperature values were collected by 3 thermocouples located at each third of the root external wall and recorded by digital thermometers. The groups irradiated in the continuous mode (CM) presented the highest values (11.82+/-5.78), regardless of the canals were dry or not, which were statistically different (p0.01). The groups irradiated with 5.0 W presented the greatest temperature variation (12.15+/-5.14), followed by 3.0 W (7.88+/-3.92) and 1.5 W (4.02+/-2.16), differing between them (ptemperature rises (9.68+/-5.80), followed by the middle (7.66+/-4.87) and apical (6.70+/-4.23), with statistical difference among them (ptemperature variation lower than 10 degrees C. Application of 980-nm diode laser in the root, at 1.5 W in all operating modes, and 3.0 W, in the pulsed mode, for 20s, can safely be used in endodontic treatment, irrespective of the presence of humidity.

  11. Egg size variation among tropical and temperate songbirds: An embryonic temperature hypothesis

    Science.gov (United States)

    Martin, T.E.

    2008-01-01

    Species with 'slow' life history strategies (long life, low fecundity) are thought to produce high-quality offspring by investing in larger, but fewer, young. Larger eggs are indeed associated with fewer eggs across taxa and can yield higher-quality offspring. Tropical passerines appear to follow theory because they commonly exhibit slow life history strategies and produce larger, but fewer, eggs compared with northern species. Yet, I show here that relative egg mass (corrected for adult mass) varies extensively in the tropics and subtropics for the same clutch size, and this variation is unexplained. I propose a hypothesis to explain egg size variation both within the tropics and between latitudes: Relative egg mass increases in species with cooler egg temperatures and longer embryonic periods to offset associated increases in energetic requirements of embryos. Egg temperatures of birds are determined by parental incubation behavior and are often cooler among tropical passerines because of reduced parental attentiveness of eggs. Here, I show that cooler egg temperatures and longer embryonic periods explained the enigmatic variation in egg mass within and among regions, based on field studies in tropical Venezuela (36 species), subtropical Argentina (16 species), and north temperate Arizona (20 species). Alternative explanations are not supported. Thus, large egg sizes may reflect compensation for increased energetic requirements of cool egg temperatures and long embryonic periods that result from reduced parental attentiveness in tropical birds. ?? 2008 by The National Academy of Sciences of the USA.

  12. Lake-level variations and tides in Lago Argentino, Patagonia: insights from pressure tide gauge records

    Directory of Open Access Journals (Sweden)

    Andreas Richter

    2015-08-01

    Full Text Available Based on precise pressure tide gauge observations lake-level records are derived for two sites in Lago Argentino, southern Patagonia, of 2.5 and 1 years of duration. Applying the tools of time series analysis, the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle of 1.2 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. Sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in Lago Argentino are dominated by surface seiches reaching 20 cm in amplitude. Lake tides reach a maximum amplitude of 3 mm. The comparison of the tidal signal extracted from the lake-level observations with a model composed of the contributions of body tide and ocean tidal loading indicates a phase shift of 23° which is most likely explained by an 1 hour phase lag of global ocean tide models in the region of the highly fragmented Pacific coast. The comparison of the obtained results with those of a previous study of Lago Fagnano, Tierra del Fuego, allows to relate differences in the hydrological and hydrodynamic processes between both lakes to morphological properties. This leads to a tentative prediction of the lake-level variability to be expected from other great Patagonian lakes. The presented geodetic results shall serve as a starting point for a detailed limnological investigation of these aquatic ecosystems.

  13. Identification of the driving forces of climate change using the longest instrumental temperature record

    Science.gov (United States)

    Wang, Geli; Yang, Peicai; Zhou, Xiuji

    2017-04-01

    The identification of causal effects is a fundamental problem in climate change research. Here, a new perspective on climate change causality is presented using the central England temperature (CET) dataset, the longest instrumental temperature record, and a combination of slow feature analysis and wavelet analysis. The driving forces of climate change were investigated and the results showed two independent degrees of freedom —a 3.36-year cycle and a 22.6-year cycle, which seem to be connected to the El Niño-Southern Oscillation cycle and the Hale sunspot cycle, respectively. Moreover, these driving forces were modulated in amplitude by signals with millennial timescales.

  14. Determination of temperature variation on lunar surface and subsurface for habitat analysis and design

    Science.gov (United States)

    Malla, Ramesh B.; Brown, Kevin M.

    2015-02-01

    The ambient environmental factors present on the lunar surface pose some of the most difficult challenges for the success of a long-term human settlement on the Moon. Aside from the dangerous radiation levels and hypervelocity micrometeoroid impacts, the equatorial temperature on the surface of the Moon can range from 102.4 K to 387.1 K. These extremes pose a variety of complications like thermal expansion and contraction, which can, in turn, alter the static, dynamic, and frequency response of a structure. This paper first presents the analytical study of the surface and subsurface thermal/heat flow environments of a potential habitat site located at the Equator of the Moon using a general equation that was developed based on the thermodynamic principle of heat flow to determine the temperature variation/gradient with time as well as depth. This method was then applied, with appropriate modifications, to determine the temperature variation with time and through depth of a 1-m thick regolith shielding layer surrounding a lunar structure. The solution to the general equation was determined through the use of the fourth-order Runge-Kutta technique of numerical integration. The analysis results showed that the outermost layer of regolith fluff has very strong insulating capabilities causing the temperature to drop 132.3 K from the maximum daytime magnitude of 387.1 K within the first 30 cm at which point it then remains constant with increasing depth. At night, the temperature increases from the minimum magnitude of 102.4 K to 254.8 K within the outermost 30 cm. When considering a layer of regolith shielding atop a lunar habitat, the added albedo radiation input from the adjacent lunar surface to the structure increased the maximum daytime surface temperature to 457 K (about 70 K higher than the lunar surface temperature) and displayed a drop of 138 K within the first 30 cm depth of regolith cover. The minimum temperature at night increased 80.3 K over the surface

  15. Influence of diurnal variations in stream temperature on streamflow loss and groundwater recharge

    Science.gov (United States)

    Constantz, Jim; Thomas, Carole L.; Zellweger, Gary W.

    1994-01-01

    We demonstrate that for losing reaches with significant diurnal variations in stream temperature, the effect of stream temperature on streambed seepage is a major factor contributing to reduced afternoon streamflows. An explanation is based on the effect of stream temperature on the hydraulic conductivity of the streambed, which can be expected to double in the 0° to 25°C temperature range. Results are presented for field experiments in which stream discharge and temperature were continuously measured for several days over losing reaches at St. Kevin Gulch, Colorado, and Tijeras Arroyo, New Mexico. At St. Kevin Gulch in July 1991, the diurnal stream temperature in the 160-m study reach ranged from about 4° to 18°C, discharges ranged from 10 to 18 L/s, and streamflow loss in the study reach ranged from 2.7 to 3.7 L/s. On the basis of measured stream temperature variations, the predicted change in conductivity was about 38%; the measured change in stream loss was about 26%, suggesting that streambed temperature varied less than the stream temperature. At Tijeras Arroyo in May 1992, diurnal stream temperature in the 655-m study reach ranged from about 10° to 25°C and discharge ranged from 25 to 55 L/s. Streamflow loss was converted to infiltration rates by factoring in the changing stream reach surface area and streamflow losses due to evaporation rates as measured in a hemispherical evaporation chamber. Infiltration rates ranged from about 0.7 to 2.0 m/d, depending on time and location. Based on measured stream temperature variations, the predicted change in conductivity was 29%; the measured change in infiltration was also about 27%. This suggests that high infiltration rates cause rapid convection of heat to the streambed. Evapotranspiration losses were estimated for the reach and adjacent flood plain within the arroyo. On the basis of these estimates, only about 5% of flow loss was consumed via stream evaporation and stream-side evapotranspiration

  16. Variations in erosive wear of metallic materials with temperature via the electron work function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaochen; Yu, Bin [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Yan, X.G. [School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China); Li, D.Y., E-mail: dongyang.li@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China)

    2016-04-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  17. Influence of Temperature Variation on Optical Receiver Sensitivity and its Compensation

    Directory of Open Access Journals (Sweden)

    A. Prokes

    2007-09-01

    Full Text Available In the paper, the influence of temperature variation on the sensitivity of an avalanche-photodiode-based optical receiver applied in the free space optical communication link is discussed. Communication systems of this type are exposed to a wide range of operating temperatures, which markedly affect many photodiode and preamplifier parameters. The paper presents a receiver sensitivity calculation, taking into consideration the temperature dependence of avalanche photodiode gain, excess noise factor, dark current and thermal noise of preamplifier resistances, and describes the compensation of temperature effects on photodiode gain based on a corresponding change in the reverse voltage applied to the diode. The calculations are demonstrated on the connection of a small-area silicon APD operating in the wavelength range from 820 to 1150 nm with a transimpedance preamplifier using a bipolar junction transistor.

  18. Finite temperature and the Polyakov loop in the covariant variational approach to Yang-Mills Theory

    Science.gov (United States)

    Quandt, Markus; Reinhardt, Hugo

    2017-03-01

    We extend the covariant variational approach for Yang-Mills theory in Landau gauge to non-zero temperatures. Numerical solutions for the thermal propagators are presented and compared to high-precision lattice data. To study the deconfinement phase transition, we adapt the formalism to background gauge and compute the effective action of the Polyakov loop for the colour groups SU(2) and SU(3). Using the zero-temperature propagators as input, all parameters are fixed at T = 0 and we find a clear signal for a deconfinement phase transition at finite temperatures, which is second order for SU(2) and first order for SU(3). The critical temperatures obtained are in reasonable agreement with lattice data.

  19. Real-time electrical impedimetric monitoring of blood coagulation process under temperature and hematocrit variations conducted in a microfluidic chip.

    Directory of Open Access Journals (Sweden)

    Kin Fong Lei

    Full Text Available Blood coagulation is an extremely complicated and dynamic physiological process. Monitoring of blood coagulation is essential to predict the risk of hemorrhage and thrombosis during cardiac surgical procedures. In this study, a high throughput microfluidic chip has been developed for the investigation of the blood coagulation process under temperature and hematocrit variations. Electrical impedance of the whole blood was continuously recorded by on-chip electrodes in contact with the blood sample during coagulation. Analysis of the impedance change of the blood was conducted to investigate the characteristics of blood coagulation process and the starting time of blood coagulation was defined. The study of blood coagulation time under temperature and hematocrit variations was shown a good agreement with results in the previous clinical reports. The electrical impedance measurement for the definition of blood coagulation process provides a fast and easy measurement technique. The microfluidic chip was shown to be a sensitive and promising device for monitoring blood coagulation process even in a variety of conditions. It is found valuable for the development of point-of-care coagulation testing devices that utilizes whole blood sample in microliter quantity.

  20. Spatial variation in near-ground radiation and low temperature. Interactions with forest vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Blennow, K.

    1997-10-01

    Low temperature has a large impact on the survival and distribution of plants. Interactive effects with high irradiance lead to cold-induced photo inhibition, which may impact on the establishment and growth of tree seedlings. In this thesis, novel approaches are applied for relating the spatial variability in low temperature and irradiance to photosynthetic performance and growth of tree seedlings, and for modelling the micro- and local-scale spatial variations in low temperature for heterogeneous terrain. The methodologies include the development and use of a digital image analysis system for hemispherical photographs, the use of Geographic Information Systems (GIS) and statistical methods, field data acquisition of meteorological elements, plant structure, growth and photosynthetic performance. Temperature and amounts of intercepted direct radiant energy for seedlings on clear days (IDRE) were related to chlorophyll a fluorescence, and the dry weight of seedlings. The combination of increased IDRE with reduced minimum temperatures resulted in persistent and strong photo inhibition as the season progressed, with likely implications for the establishment of tree seedlings at forest edges, and within shelter wood. For models of spatial distribution of low air temperature, the sky view factor was used to parameterize the radiative cooling, whilst drainage, ponding and stagnation of cold air, and thermal properties of the ground were all considered. The models hint at which scales and processes govern the development of spatial variations in low temperature for the construction of corresponding mechanistic models. The methodology is well suited for detecting areas that will be frost prone after clearing of forest and for comparing the magnitudes of impacts on low air temperature of forest management practices, such as shelter wood and soil preparation. The results can be used to formulate ground rules for use in practical forestry 141 refs, 5 figs, 1 tab

  1. Culture temperature modulates monoclonal antibody charge variation distribution in Chinese hamster ovary cell cultures.

    Science.gov (United States)

    Zhang, Xintao; Sun, Ya-Ting; Tang, Hongping; Fan, Li; Hu, Dongdong; Liu, Jintao; Liu, Xuping; Tan, Wen-Song

    2015-11-01

    To investigate the effect of lowering culture temperature on monoclonal antibody charge variation distribution in Chinese hamster ovary cell cultures. In both batch and fed-batch cultures, lowering the culture temperature decreased the antibody acidic variant levels. The acidic variant levels (defined as variants eluting earlier than the main peak of an antibody during HPLC) at 32 °C were about 10 % lower than those at 37 °C at the end of both batch and fed-batch cultures. Additionally, lowering the culture temperature increased the lysine variant level, which further increased basic variant level. The lysine variant levels at 32 °C were about 8 % (batch culture) and 3 % (fed-batch culture) higher than those at 37 °C at the end of cultures. Real-time PCR results suggests that the decrease in carboxypeptidase B transcription level might be partially responsible for the increased lysine variant level at sub-physiological temperatures. Culture temperature exhibits noticeable impact on antibody charge variation distribution, especially the acidic variants and lysine variants.

  2. Geographic variation in the diet of opaleye (Girella nigricans with respect to temperature and habitat.

    Directory of Open Access Journals (Sweden)

    Michael D Behrens

    Full Text Available We studied diet variation in an omnivorous fish across its range, which allowed us to test predictions about the effect of ocean temperature and habitat on herbivory. Throughout most of its geographic range, from Southern California to central Baja California, the opaleye (Girella nigricans fed primarily on red and green algae, but there was significant variation in the amount of algal material in the diet among sites. The proportion of algal material in the diet was related to habitat, with algae making up a larger proportion of a fish's diet in algal-dominated habitats than in urchin barrens. Independent of habitat, the proportion of algal material in the diet increased with environmental temperature. Analyses of stable isotopes revealed similar changes in trophic position and confirmed that these associations with diet persisted over relatively long time scales. The shift to a more herbivorous diet at warmer temperatures is in agreement with past laboratory studies on this species that show a diet-dependent change in performance with temperature and can indicate a diet shift across the species' geographic range to meet its physiological demands. A possible plastic response to herbivory was a longer gut relative to body size. The results of this study are consistent with past findings that associate temperature with increases in the relative diversity of herbivorous fishes in tropical parts of the ocean.

  3. Ontogenetic variations in flush development are indicative of low temperature tolerance in Hevea brasiliensis clones

    Directory of Open Access Journals (Sweden)

    K.K. Vinod

    2010-09-01

    Full Text Available Para rubber (Hevea brasiliensis trees are naturally adapted to the Amazonian tropical climate. In India rubber trees are traditionally cultivated in the warm humid tropics of the south. Northeast India is a non-traditional area for rubber cultivation. A major limiting factor on tree growth in the northeast region is stress due to low temperature. Being a deciduous tree, rubber trees exhibit annual natural defoliation prior to the winter season, and ensuing new leaf growth usually coincides with the low temperature period. Flushing behaviour of trees during this period provides an opportunity to assess their winter hardiness. A study was carried out on five clones, RRIM 600, SCATC 93/114, GT 1, PB 5/51 and Haiken 1, to evaluate phenological behaviour of leaf growth during the period of low temperature stress. Trees were monitored for expansion of leaf area, internode length, petiole length and development of chlorophyll. Wide variation was observed among these clones for all the traits. SCATC 93/114 was better adapted for low temperaturestress as this clone was found to have faster expansion of leaf area and better chlorophyll development, followed by Haiken 1. PB 5/51 was found to show poor performance during low temperature. Haiken 1 and PB 5/51 also exhibited better relative growth rate during winter months confirming their low temperature tolerance. Ontogenetic variations in leaf development are good indicators of assessing inherent cold tolerance in Hevea clones.

  4. Temperature Variations of Saturn Rings with Viewing Geometries from Prime to Equinox Cassini Missions

    Science.gov (United States)

    Deau, E. A.; Spilker, L. J.; Morishima, R.; Brooks, S.; Pilorz, S.; Altobelli, N.

    2011-01-01

    After more than six years in orbit around Saturn, the Cassini Composite Infrared Spectrometer (CIRS) has acquired an extensive set of measurements of Saturn's main rings (A, B, C and Cassini Division) in the thermal infrared. Temperatures were retrieved for the lit and unlit rings over a variety of ring geometries that include phase angle, solar and spacecraft elevations and local time. We show that some of these parameters (solar and spacecraft elevations, phase angle) play a role in the temperature variations in the first order, while the others (ring and particle local time) produced second order effects. The results of this comparison will be presented.

  5. Sea Surface Temperature Climate Data Record for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Høyer, Jacob L.; Karagali, Ioanna

    2016-01-01

    A 30-yr climate data record (CDR) of sea surface temperature (SST) has been produced with daily gap-free analysis fields for the North Sea and the Baltic Sea region from 1982 to 2012 by combining the Pathfinder AVHRR satellite data record with the Along-Track Scanning Radiometer (ATSR) Reprocessing...... observations on average. Validation against independent in situ observations shows a very stable performance of the data record, with a mean difference of -0.06 °C compared to moored buoys and a 0.46 °C standard deviation of the differences. The mean annual biases of the SST CDR are small for all years......, with a negligible temporal trend when compared against drifting and moored buoys. Analysis of the SST CDR reveals that the monthly anomalies for the North Sea, the Danish straits, and the central Baltic Sea regions show a high degree of correlation for interannual and decadal time scales, whereas the monthly...

  6. A further contribution to the seasonal variation of weighted mean temperature

    Science.gov (United States)

    Ding, Maohua; Hu, Wusheng

    2017-12-01

    The weighted mean temperature Tm is a variable parameter in the Global Navigation Satellite System (GNSS) meteorology and the Askne-Nordius zenith wet delay (ZWD) model. Some parameters about the Tm seasonal variation (e.g. the annual mean value, the annual range, the annual and semi-annual amplitudes, and the long-term trend) were discussed before. In this study, some additional results about the Tm seasonal variation on a global scale were found by using the Tm time series at 309 global radiosonde sites. Periodic signals of the annual and semi-annual variations were detected in these Tm time series by using the Lomb-Scargle periodogram. The annual variation is the main component of the periodic Tm in non-tropical regions, while the annual variation or the semiannual variation can be the main component of the periodic Tm in tropics. The mean annual Tm almost keeps constant with the increasing latitude in tropics, while it decreases with the increasing latitude in non-tropical regions. From a global perspective, Tm has an increasing trend of 0.22 K/decade on average, which may be caused by the global warming effects. The annual phase is almost found in about January for the non-tropical regions of the Southern Hemisphere and in about July for the non-tropical regions of the Northern Hemisphere, but it has no clear symmetry in tropics. Unlike the annual phase, the geographical distributions of semi-annual phase do not follow obvious rules. In non-tropical regions, the maximum and minimum Tm of the seasonal model are usually found in respective summer and winter days while the maximum and minimum Tm are distributed over a whole year but not in any fixed seasons for tropical regions. The seasonal model errors increase with the increasing value of annual amplitude. A primary reason for the irregular seasonal variation in tropics is that Tm has rather small variations in this region.

  7. Impacts of rainfall and air temperature variations due to climate change upon hydrological characteristics: A case study

    Science.gov (United States)

    Ying Ouyang; Jia-En Zhang; Yide Li; Prem Parajuli; Gary Feng

    2015-01-01

    Rainfall and air temperature variations resulting from climate change are important driving forces to change hydrologic processes in watershed ecosystems. This study investigated the impacts of past and future rainfall and air temperature variations upon water discharge, water outflow (from the watershed outlet), and evaporative loss in the Lower Yazoo River Watershed...

  8. Impacts of rainfall and air temperature variations due to climate change upon hydrological characteristics: a case study

    Science.gov (United States)

    Rainfall and air temperature variations resulting from climate change are important driving forces to alter hydrologic processes in watershed ecosystems. This study investigated impacts of past and potential future rainfall and air temperature variations upon water discharge, water outflow (from th...

  9. Elastocaloric effect on natural rubber and terpolymer : Temperature variation mechanism, morphology and energy balance during deformation

    OpenAIRE

    Yoshida 1988-...., Yukihiro

    2016-01-01

    Caloric effects (CEs), which are the phenomena that temperature variation is caused by entropy change, have been investigated for the novel system which might be able to replace conventional vapor compression refrigeration system. In the present thesis, the elastocaloric effect (ElCE) of natural rubber (NR) and terpolymer, poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)), was focused. First of all, NR, which is an excellent candidate material for ElCE, wa...

  10. Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands

    Science.gov (United States)

    Liu, Yuan; He, Nianpeng

    2017-04-01

    How to assess the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition and its regional variation with high accuracy is one of the largest uncertainties in determining the intensity and direction of the global carbon (C) cycle in response to climate change. In this study, we collected a series of soils from 22 forest sites and 30 grassland sites across China to explore regional variation in Q10 and its underlying mechanisms. We conducted a novel incubation experiment with periodically changing temperature (5-30 °C), while continuously measuring soil microbial respiration rates. The results showed that Q10 varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q10 was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q10 of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q10 significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q10 across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q10. The general negative relationships between Q10 and substrate quality among all ecosystem types supported the C quality temperature (CQT) hypothesis at a large scale, which indicated that soils with low quality should have higher temperature sensitivity. Furthermore, alpine grasslands, which had the highest Q10, were predicted to be more sensitive to climate change under the scenario of global warming.

  11. Young modulus variation of a brickwork masonry element submitted to high temperatures

    Directory of Open Access Journals (Sweden)

    Maciá, M. E.

    2013-03-01

    Full Text Available In order to understand the thermal behavior of the masonry elements submitted to high temperatures we need to know the variation of their thermal properties with regard to the temperature. Submitted to high temperatures clay brick masonry presents thermomechanical effects (as the variation of Young's modulus, the thermal expansion of the unit and the mortar, spalling, losses of resistance … as well as variation of the properties of the material as result of its degradation. In this article the variation of the module of elasticity of the unit and the mortar is described with regard to high temperatures according to the state of the knowledge. In this article is also exposed the results obtained from the experimental program carried out on elements of clay brick masonry submitted to high temperatures in order to observe the variation of Young's module related to temperature.

    La definición del comportamiento térmico de los elementos de fábrica sometidos a la acción del fuego requiere del conocimiento de la variación de sus propiedades termomecánicas con respecto a la temperatura. Ante las altas temperaturas la fábrica cerámica presenta efectos termomecánicos, como la variación del módulo de Young entre otros, así como la variación de las propiedades del material debidas a la degradación del mismo. En este artículo se describe la variación del módulo de elasticidad de la pieza y el mortero con respecto a altas temperaturas según el estado del conocimiento y se exponen los resultados obtenidos del programa experimental llevado a cabo sobre elementos de fábrica sometidos a altas temperaturas con el fin de observar la variación del módulo de Young con respecto a la temperatura.

  12. Tooth counts through growth in diapsid reptiles: implications for interpreting individual and size-related variation in the fossil record.

    Science.gov (United States)

    Brown, Caleb Marshall; VanBuren, Collin S; Larson, Derek W; Brink, Kirstin S; Campione, Nicolás E; Vavrek, Matthew J; Evans, David C

    2015-04-01

    Tooth counts are commonly recorded in fossil diapsid reptiles and have been used for taxonomic and phylogenetic purposes under the assumption that differences in the number of teeth are largely explained by interspecific variation. Although phylogeny is almost certainly one of the greatest factors influencing tooth count, the relative role of intraspecific variation is difficult, and often impossible, to test in the fossil record given the sample sizes available to palaeontologists and, as such, is best investigated using extant models. Intraspecific variation (largely manifested as size-related or ontogenetic variation) in tooth counts has been examined in extant squamates (lizards and snakes) but is poorly understood in archosaurs (crocodylians and dinosaurs). Here, we document tooth count variation in two species of extant crocodylians (Alligator mississippiensis and Crocodylus porosus) as well as a large varanid lizard (Varanus komodoensis). We test the hypothesis that variation in tooth count is driven primarily by growth and thus predict significant correlations between tooth count and size, as well as differences in the frequency of deviation from the modal tooth count in the premaxilla, maxilla, and dentary. In addition to tooth counts, we also document tooth allometry in each species and compare these results with tooth count change through growth. Results reveal no correlation of tooth count with size in any element of any species examined here, with the exception of the premaxilla of C. porosus, which shows the loss of one tooth position. Based on the taxa examined here, we reject the hypothesis, as it is evident that variation in tooth count is not always significantly correlated with growth. However, growth trajectories of smaller reptilian taxa show increases in tooth counts and, although current samples are small, suggest potential correlates between tooth count trajectories and adult size. Nevertheless, interspecific variation in growth patterns

  13. Nationwide variation in the effects of temperature on infectious gastroenteritis incidence in Japan

    Science.gov (United States)

    Onozuka, Daisuke; Hagihara, Akihito

    2015-08-01

    Although several studies have investigated the effects of temperature on the incidence of infectious gastrointestinal disease in a single city or region, few have investigated variations in this association using nationwide data. We obtained weekly data, gathered between 2000 and 2012, pertaining to infectious gastroenteritis cases and weather variability in all 47 Japanese prefectures. A two-stage analysis was used to assess the nonlinear and delayed relationship between temperature and morbidity. In the first stage, a Poisson regression allowing for overdispersion in a distributed lag nonlinear model was used to estimate the prefecture-specific effects of temperature on morbidity. In the second stage, a multivariate meta-analysis was applied to pool estimates at the national level. The pooled overall relative risk (RR) was highest in the 59.9th percentile of temperature (RR, 1.08; 95% CI: 1.01, 1.15). Meta-analysis results also indicated that the estimated pooled RR at lower temperatures (25th percentile) began immediately but did not persist, whereas an identical estimate at a higher temperature (75th percentile) was delayed but persisted for several weeks. Our results suggest that public health strategies aimed at controlling temperature-related infectious gastroenteritis may be more effective when tailored according to region-specific weather conditions.

  14. Intrapupal temperature variation during Er,Cr: YSGG enamel irradiation on carries prevention

    Directory of Open Access Journals (Sweden)

    Patrícia Moreira de Freitas

    2008-04-01

    Full Text Available Studies have shown the cariostatic effect of Er,Cr:YSGG (2.78 mm laser irradiation on human enamel and have suggested its use on caries prevention. However there are still no reports on the intrapulpal temperature increase during enamel irradiation using parameters for caries prevention. The aim of this in vitro study was to evaluate the temperature variation in the pulp chamber during human enamel irradiation with Er,Cr:YSGG laser at different energy densities. Fifteen enamel blocks obtained from third molars (3 x 3 x 3 mm were randomly assigned to 3 groups (n=5: G1 - Er,Cr:YSGG laser 0.25 W, 20 Hz, 2.84 J/cm², G2 - Er,Cr:YSGG laser 0.50 W, 20 Hz, 5.68 J/cm², G3 - Er,Cr:YSGG laser 0.75 W, 20 Hz, 8.52 J/cm². During enamel irradiation, two thermocouples were fixed in the inner surface of the specimens and a thermal conducting paste was used. One-way ANOVA did not show statistically significant difference among the experimental groups (a=0.05. There was intrapulpal temperature variation <0.1ºC for all irradiation parameters. In conclusion, under the tested conditions, the use of Er,Cr:YSGG laser with parameters set for caries prevention lead to an acceptable temperature increase in the pulp chamber.

  15. Response of subsurface soils covered by sand clay liners to temperature variations

    Science.gov (United States)

    Dafalla, Muawia

    2017-04-01

    The use of sand clay liners as a cover for near surface material works as a heat insulator as well as a hydraulic barrier. The soil temperature profile below grade level is normally a function of soil type, dampness and state of compaction. The temperature rise and fall is closely related to the moisture content conditions within the strata. This study is aimed at investigating the effect of a sand clay liner placed on ground surface on the temperature moisture profile. A section of clay sand liners was constructed on site on top of a silty sand formation with some clay. The field section was observed for variable temperature and weather conditions over six month's period. 5TE Decagon sensors capable of recording moisture content, temperature and electrical conductivity connected to Em50 data loggers were employed. A weather station equipped with rainfall, temperature, humidity and wind sensors was installed on site throughout the period of the investigation. The measurements of electrical conductivity were found extremely sensitive to wetting and drying and to temperature changes. Profiles for dry soil being wetted and wet soil being dried out are presented and compared in this study. Mineralogy and chemical composition of the subsurface soil in addition to the chemistry of water do have a remarkable influence on shaping these profiles.

  16. Temperature distribution in side- and end-pumped laser crystal rods - Temporal and spatial variations

    Science.gov (United States)

    Farrukh, Usamah O.; Brockman, Philip

    1993-01-01

    Knowledge of the temperature distribution of laser rods end pumped by laser diodes or other laser systems is relevant when thermal stress and crystal damage are expected. The temperature of a multipulsed or continuously pumped laser rod is given as a double-series expression and as a function of time. The mathematical model considers all surface cooling rates, the spatial and temporal variations of the pump beam, and the specific heat and thermal conductivity of the rod material. This eigenfunction expansion representation was employed to predict the spatial and time-dependent quasi-steady-state temperature in Ti:sapphire, Nd:YAG, and Cr:LiSAF laser rods of specific dimensions.

  17. Temperature distribution in side- and end-pumped laser crystal rods: temporal and spatial variations.

    Science.gov (United States)

    Farrukh, U O; Brockman, P

    1993-04-20

    Knowledge of the temperature distribution of laser rods end pumped by laser diodes or other laser systems is relevant when thermal stress and crystal damage are expected. The temperature of a multipulsed or continuously pumped laser rod is given as a double-series expression and as a function of time. The mathematical model considers all surface cooling rates, the spatial and temporal variations of the pump beam, and the specific heat and thermal conductivity of the rod material. This eigenfunction expansion representation was employed to predict the spatial and time-dependent quasi-steady-state temperature in Ti:sapphire, Nd:YAG, and Cr:LiSAF laser rods of specific dimensions.

  18. Numerical Study on the Effect of Buildings on Temperature Variation in Urban and Suburban Areas in Tokyo

    OpenAIRE

    Takayuki, TOKAIRIN; Hiroaki, Kondo; Hiroshi, YOSHIKADO; Yutaka, Genchi; Tomohiko, IHARA; Yukihiro, KIKEGAWA; Yujiro, Hirano; Kazutake, ASAHI; National Institute of Advanced Industrial Science and Technology; Meisei University; Gunma University; Mizuho Information & Research Institute, Inc.

    2006-01-01

    A numerical investigation of the temperature variation in urban and suburban areas due to the presence of buildings was carried out using a one-dimensional canopy model combined with a meso-scale meteorological model. Since temperature increases in an urban area are caused by sensible heat from building surfaces besides anthropogenic heat and reduction of wind speed due to buildings' drag, we estimated each cause separately to determine the contribution by each to the temperature variation. T...

  19. Empirical analysis of skin friction under variations of temperature; Variacion de la resistencia al corte con temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Parra Alvarez, A. R. de la; Groot Viana, M. de

    2014-07-01

    In soil geotechnical characterization, strength parameters, cohesion (c) and internal friction angle (Φ) has been traditional measured without taking into account temperature, been a very important issue in energy geostructures. The present document analyzes the variation of these parameters in soil-concrete interface at different temperatures. A traditional shear strength case with a forced plane of failure was used. Several tests were carried out to determine the variation of skin friction in granular and cohesive oils with temperature. (Author)

  20. Spatiotemporal variations of annual shallow soil temperature on the Tibetan Plateau during 1983-2013

    Science.gov (United States)

    Zhu, Fuxin; Cuo, Lan; Zhang, Yongxin; Luo, Jing-Jia; Lettenmaier, Dennis P.; Lin, Yumei; Liu, Zhe

    2017-11-01

    Soil temperature changes in cold regions can have great impacts on the land surface energy and water balance, and hence changes in weather and climate, surface and subsurface hydrology and ecosystem. We investigate the spatiotemporal variations of annual soil temperature at depths of 0, 5, 10, 15, 20, and 40 cm during 1983-2013 using observations at 85 stations on the Tibetan Plateau (TP). Our results show that the climatological soil temperatures exhibit a similar spatial pattern among different depths and they are generally higher than surface air temperature at the individual stations. Spatially averaged soil temperature show that the TP has experienced significant warming trends at all six depths during 1983-2013, and the soil at 0-cm depth has the fastest warming rate among all the six layers and the surface air temperature. The first leading mode of joint empirical orthogonal function (EOF) analysis exhibits a spatially prevailing warming pattern across the six depths. This plateau-wide soil warming correlates very well with surface air temperature and sea surface temperature in response to increasing radiative forcing caused by greenhouse gases. The joint EOF2 displays a southeastern-northwestern dipole pattern on the TP in the interannual-decadal variability of soil temperature at all layers, which appears to be related to the warm season precipitation and anomalous atmospheric circulations. The spatial difference of soil warming rates across stations on the TP is associated primarily with the spatial distribution of precipitation (mainly rainfall), with vegetation, snowfall and elevation playing a rather limited role.

  1. Circadian variation in QT dispersion determined from a 12-lead Holter recording

    DEFF Research Database (Denmark)

    Hansen, S; Rasmussen, Verner; Larsen, Klaus

    2007-01-01

    Background: QT dispersion is considered to reflect inhomogeneity of myocardial repolarization. Method: The circadian variation of QT interval dispersion was examined in 95 healthy subjects using 24-hour Holter monitoring. Three different methods of lead selection were applied: all 12 leads (QTdisp...... 12), only precordial leads (QTdisp 6), and the pair of leads selected at 3 a.m. in which the longest and shortest QT intervals were found in each individual subject (QTdisp 2). Results: A preliminary methodological study including measurements from every minute in 10 subjects revealed no significant...... a significant circadian variation was seen in QTdisp 12 (P QT dispersion. Circadian variation was detected...

  2. Three-dimensional temperature fields of the North Patagonian Sea recorded by Magellanic penguins as biological sampling platforms

    Science.gov (United States)

    Sala, Juan E.; Pisoni, Juan P.; Quintana, Flavio

    2017-04-01

    Temperature is a primary determinant of biogeographic patterns and ecosystem processes. Standard techniques to study the ocean temperature in situ are, however, particularly limited by their time and spatial coverage, problems which might be partially mitigated by using marine top predators as biological platforms for oceanographic sampling. We used small archival tags deployed on 33 Magellanic penguins (Spheniscus magellanicus), and obtained 21,070 geo-localized profiles of water temperature, during late spring of 2008, 2011, 2012 and 2013; in a region of the North Patagonian Sea with limited oceanographic records in situ. We compared our in situ data of sea surface temperature (SST) with those available from satellite remote sensing; to describe the three-dimensional temperature fields around the area of influence of two important tidal frontal systems; and to study the inter-annual variation in the three-dimensional temperature fields. There was a strong positive relationship between satellite- and animal-derived SST data although there was an overestimation by remote-sensing by a maximum difference of +2 °C. Little inter-annual variability in the 3-dimensional temperature fields was found, with the exception of 2012 (and to a lesser extent in 2013) where the SST was significantly higher. In 2013, we found weak stratification in a region which was unexpected. In addition, during the same year, a warm small-scale vortex is indicated by the animal-derived temperature data. This allowed us to describe and better understand the dynamics of the water masses, which, so far, have been mainly studied by remote sensors and numerical models. Our results highlight again the potential of using marine top predators as biological platforms to collect oceanographic data, which will enhance and accelerate studies on the Southwest Atlantic Ocean. In a changing world, threatened by climate change, it is urgent to fill information gaps on the coupled ocean-atmosphere system

  3. Future summer mega-heatwave and record-breaking temperatures in a warmer France climate

    Science.gov (United States)

    Bador, Margot; Terray, Laurent; Boé, Julien; Somot, Samuel; Alias, Antoinette; Gibelin, Anne-Laure; Dubuisson, Brigitte

    2017-07-01

    This study focuses on future very hot summers associated with severe heatwaves and record-breaking temperatures in France. Daily temperature observations and a pair of historical and scenario (greenhouse gas radiative concentration pathway 8.5) simulations with the high-resolution (∼12.5 km) ALADIN regional climate model provide a robust framework to examine the spatial distribution of these extreme events and their 21st century evolution. Five regions are identified with an extreme event spatial clustering algorithm applied to observed temperatures. They are used to diagnose the 21st century heatwave spatial patterns. In the 2070s, we find a simulated mega-heatwave as severe as the 2003 observed heatwave relative to its contemporaneous climate. A 20-member initial condition ensemble is used to assess the sensitivity of this future heatwave to the internal variability in the regional climate model and to pre-existing land surface conditions. Even in a much warmer and drier climate in France, late spring dry land conditions may lead to a significant amplification of summer extreme temperatures and heatwave intensity through limitations in evapotranspiration. By 2100, the increase in summer temperature maxima exhibits a range from 6 °C to almost 13 °C in the five regions in France, relative to historical maxima. These projections are comparable with the estimates given by a large number of global climate models.

  4. Negation scope and spelling variation for text-mining of Danish electronic patient records

    DEFF Research Database (Denmark)

    Thomas, Cecilia Engel; Jensen, Peter Bjødstrup; Werge, Thomas

    2014-01-01

    Electronic patient records are a potentially rich data source for knowledge extraction in biomedical research. Here we present a method based on the ICD10 system for text-mining of Danish health records. We have evaluated how adding functionalities to a baseline text-mining tool affected...

  5. Geochemistry and Temperatures Recorded by Zircon During the Final Stages of the Youngest Toba Tuff Magma Chamber, Sumatra, Indonesia

    Science.gov (United States)

    Gaither, T.; Reid, M. R.; Vazquez, J. A.

    2009-12-01

    The ~74 ka eruption of the Youngest Toba Tuff (YTT) in Sumatra, Indonesia, was one of the largest single volcanic eruptions in geologic history, on par with other voluminous silicic eruptions such as the Huckleberry Ridge Tuff of Yellowstone and the Bishop Tuff of Long Valley, California. We are exploring how zircon and other accessory mineral phases record compositional and thermal changes that occurred in the YTT magma, and the important clues these crystal scale records hold for magma chamber dynamics and processes that lead up to supervolcano eruptions. In this study, we report trace element (REE, U, Th, Ti, and Hf) characteristics, Ti-in-zircon crystallization temperatures, and apparent REE partition coefficients obtained for YTT zircon rims. Twenty-nine zircons from pumices with a compositional range of 70-76 wt% SiO2 were analyzed on the UCLA Cameca ims 1270 ion microprobe. The grains were mounted so that only the outermost ~1.5 microns of the crystals were analyzed. Median Zr/Hf ratios of 34 to 38 characterize zircons from the pumices; the high silica rhyolite grains have lower Zr/Hf. Chondrite-normalized REE patterns are strongly LREE-depleted. Positive Ce anomalies are large (Ce/Ce* ranges up to 88) and Eu/Eu* varies by a factor of four (0.05 to 0.21). Eu/Eu*, Nd/Yb, and Th/U decrease with decreasing Zr/Hf, showing that the variation in zircon rim compositions may be related by co-precipitation of feldspar and allanite along with zircon. Titanium contents also decrease with decreasing Zr/Hf, suggesting that the chemical differences could be related to temperature changes. REE partition coefficients calculated from zircon rim compositions and pumice glass compositions give a good fit to a lattice strain model. They are also quite similar to the partition coefficients of Sano et al. (2002) which have been shown to be successful at reproducing melt compositions in other settings. Temperatures of crystallization calculated using the Ti

  6. Temperature Condition and Spherical Shell Shape Variation of Space Gauge-Alignment Spacecraft

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    Full Text Available A high precision spherical shell is one of the geometrical shape embodiments of a gaugealignment spacecraft to determine and control a radar channel energy potential of the ground-based complex for the traffic control of space objects. Passive relays of signals and some types of smallsized instrumentation standard reflectors used for radar gauge and alignment have the same shape. Orbits of the considered spacecraft can be either circular with a height of about 1000 km, including those close to the polar, or elliptical with an apogee of up to 2200 km.In case there is no thermal control system in spacecrafts of these types the solar radiation is a major factor to define the thermal state of a spherical shell in the illuminated orbit area. With the shell in fixed position with respect to direction towards the Sun an arising uneven temperature distribution over its surface leads to variation of the spherically ideal shell shape, which may affect the functional characteristics of the spacecraft. The shell rotation about an axis perpendicular to the direction towards the Sun may reduce an unevenness degree of the temperature distribution.The uneven temperature distribution over the spherical shell surface in conditions of the lowEarth space and this unevenness impact on the shell shape variation against its spherical shape can be quantively estimated by the appropriate methods of mathematical modeling using modification of a previously developed mathematical model to describe steady temperature state of such shell on the low-Earth orbit. The paper considers the shell made from a polymeric composite material. Its original spherical shape is defined by rather low internal pressure. It is assumed that equipment in the shell, if any, is quite small-sized. This allows us to ignore its impact on the radiative transfer in the shell cavity. Along with defining the steady temperature distribution over the shell surface at its fixed orientation with respect to

  7. Relationship between winter AO/NAO and temperature in China: intraseasonal and interdecadal variations

    Science.gov (United States)

    Ren, Hong-Li; Zuo, Jinqing; Li, Weijing

    2017-04-01

    In this study, we focus on the intraseasonal and interdecadal variations in the relationship between winter AO/NAO (Arctic Oscillation / North Atlantic Oscillation) and surface air temperature (SAT) in China. On one hand, our results show that there is an intraseasonal contrast in impacts of AO/NAO on SAT in the central-southern China between early and mid-late winter. The linkage between AO and central-southern China SAT strongly depends on the AO-associated changes in Middle-East Jet Stream (MEJS) and the AO-MEJS relationship is significantly different between early and mid-late winter. On the other hand, our results also clearly show that inter-decadal changes have occurred in the relationship between the winter NAO and southern China surface air temperature anomalies in the past decades. A weak in-phase relationship occurred before the early 1970s, but a significant out-of-phase relationship dominated during 1979-1998, though it has been clearly weaker from the late 1990s onwards. Observational evidence shows that such interdecadal variations are mainly related to variations in the spatial pattern and amplitude of the NAO. The eastward shift and amplitude intensification of the NAO favored a north-south Asian dipole structure of circulation anomalies, which tended to produce cold SAT anomalies in central-southern China in the positive NAO phase and warm in the negative NAO phase.

  8. Diurnal variation in temperature, mental and physical performance, and tasks specifically related to football (soccer).

    Science.gov (United States)

    Reilly, Thomas; Atkinson, Greg; Edwards, Ben; Waterhouse, Jim; Farrelly, Kelly; Fairhurst, Emma

    2007-01-01

    Football (soccer) training and matches are scheduled at different times throughout the day. Association football involves a variety of fitness components as well as psychomotor and game-related cognitive skills. The purpose of the present research, consisting of two separate studies, was to determine whether game-related skills varied with time of day in phase with global markers of both performance and the body clock. In the first study, eight diurnally active male association football players (19.1+/-1.9 yrs of age; mean+/-SD) with 10.8+/-2.1 yrs playing experience participated. Measurements were made on different days at 08:00, 12:00, 16:00, and 20:00 h in a counterbalanced manner. Time-of-day changes in intra-aural temperature (used as a marker of the body clock), grip strength, reaction times, flexibility (markers of aspects of performance), juggling and dribbling tasks, and wall-volley test (football-specific skills) were compared. Significant (repeated measures analysis of variance, ANOVA) diurnal variations were found for body temperature (pskills of juggling performance showed significant diurnal variation (ptest tended to peak at 20:00 h and dribbling showed no time-of-day effect (p=0.55). In a second study, eight diurnally active subjects (23.0+/-0.7 yrs of age) completed five test sessions, at the same times as in the first study but with a second session at 08:00 h. Test-re-test comparisons at 08:00 h for all components indicated good reliability. Intra-aural temperature showed a significant time-of-day effect (p0.05). Diurnal variation was found for performance tests, including sit-and-reach flexibility (ptests, including dribbling time (ptest performance (pskills but also measures of physical performance are at their peak. Body temperature peaked at a similar time, but positive mood states seemed to peak slightly earlier. While causal links cannot be established in these experiments, the results indicate that the diurnal variation of some aspects of

  9. GENOTYPIC VARIATION IN CHLOROPHYLL FLUORESCENCE PARAMETERS, PHOTOSYNTHESIS AND GROWTH OF TOMATO GROWN AT LOW-TEMPERATURE AND LOW IRRADIANCE

    NARCIS (Netherlands)

    JANSSEN, LHJ; VANOEVEREN, JC; VANHASSELT, PR; KUIPER, PJC

    1995-01-01

    The genetic variation in low temperature sensitivity of eight tomato genotypes grown at suboptimal temperature (19 degrees C) and at low irradiance (140 mu mol m(-2) s(-1)) was assessed at the plant, chloroplast and thylakoid membrane levels. Temperature effects on the thylakoid membrane were

  10. Appropriate threshold levels of cardiac beat-to-beat variation in semi-automatic analysis of equine ECG recordings

    DEFF Research Database (Denmark)

    Madsen, Mette Flethøj; Kanters, Jørgen K.; Pedersen, Philip Juul

    2016-01-01

    Background: Although premature beats are a matter of concern in horses, the interpretation of equine ECG recordings is complicated by a lack of standardized analysis criteria and a limited knowledge of the normal beat-to-beat variation of equine cardiac rhythm. The purpose of this study...... was to determine the appropriate threshold levels of maximum acceptable deviation of RR intervals in equine ECG analysis, and to evaluate a novel two-step timing algorithm by quantifying the frequency of arrhythmias in a cohort of healthy adult endurance horses. Results: Beat-to-beat variation differed......, range 1–24). Conclusions: Beat-to-beat variation of equine cardiac rhythm varies according to HR, and threshold levels in equine ECG analysis should be adjusted accordingly. Standardization of the analysis criteria will enable comparisons of studies and follow-up examinations of patients. A small number...

  11. Temperature variation on root surface with three root-end cavity preparation techniques

    Directory of Open Access Journals (Sweden)

    Bodrumlu Emre

    2013-01-01

    Full Text Available Introduction. Thermal changes can occur on the external root surface when root-end cavity preparation is performed, which may damage periodontal ligament cells and alveolar bone. Objective. The purpose of this study was to evaluate the temperature changes during preparation of the root-end cavities at 1 and 3 mm to the sectioned apical root surfaces when either tungsten carbide round bur, diamond round bur or ultrasonic diamond tip was used. Methods. Root-end resection was performed at 90° to the long axis of the root, 3 mm from the apex. Specimens were randomly divided into three groups of 12 teeth each for three different root-end cavity preparation techniques to be used, i.e. tungsten carbide bur, diamond bur and ultrasonic diamond retro tip. Thermocouples were used to measure temperature changes at 1 mm (T1 and 3 mm (T2 to the cutting plane during the preparations. Results. For T1, the lowest and the highest mean temperature increases of 3.53°C and 4.34°C were recorded for the carbide and diamond burs, respectively. For T2, the lowest and the highest mean temperature increases of 2.62°C and 4.39°C where recorded for the carbide and diamond burs, respectively. The mean temperatures with the ultrasonic tip were 3.68 and 3.04 ºC at T1 and T2 region, respectively. For root-end preparation, the ultrasonic preparation technique took the shortest preparation time (10.25 sec and the diamond bur took the longest time (28.17 sec. Conclusion. Ultrasonic retro tips and burs caused temperature to rise from 2.62° to 4.39°C, and these rises were within safety levels.

  12. Quantitative estimation of temperature variations in plantar angiosomes: a study case for diabetic foot.

    Science.gov (United States)

    Peregrina-Barreto, H; Morales-Hernandez, L A; Rangel-Magdaleno, J J; Avina-Cervantes, J G; Ramirez-Cortes, J M; Morales-Caporal, R

    2014-01-01

    Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regarding ulceration risks. The early detection of ulceration risks is considered an important research topic in the medicine field, as its objective is to avoid major complications that might lead to a limb amputation. The absence of symptoms in the early phase of the ulceration is conceived as the main disadvantage to provide an opportune diagnostic in subjects with neuropathy. Since the relation between temperature and ulceration risks is well established in the literature, a methodology that obtains quantitative temperature differences in the plantar area of the diabetic foot to detect ulceration risks is proposed in this work. Such methodology is based on the angiosome concept and image processing.

  13. Quantitative Estimation of Temperature Variations in Plantar Angiosomes: A Study Case for Diabetic Foot

    Directory of Open Access Journals (Sweden)

    H. Peregrina-Barreto

    2014-01-01

    Full Text Available Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regarding ulceration risks. The early detection of ulceration risks is considered an important research topic in the medicine field, as its objective is to avoid major complications that might lead to a limb amputation. The absence of symptoms in the early phase of the ulceration is conceived as the main disadvantage to provide an opportune diagnostic in subjects with neuropathy. Since the relation between temperature and ulceration risks is well established in the literature, a methodology that obtains quantitative temperature differences in the plantar area of the diabetic foot to detect ulceration risks is proposed in this work. Such methodology is based on the angiosome concept and image processing.

  14. An Inter-calibrated Passive Microwave Brightness Temperature Data Record and Ocean Products

    Science.gov (United States)

    Hilburn, K. A.; Wentz, F. J.

    2014-12-01

    Inter-calibration of passive microwave sensors has been the subject of on-going activity at Remote Sensing Systems (RSS) since 1974. RSS has produced a brightness temperature TB data record that spans the last 28 years (1987-2014) from inter-calibrated passive microwave sensors on 14 satellites: AMSR-E, AMSR2, GMI, SSMI F08-F15, SSMIS F16-F18, TMI, WindSat. Accompanying the TB record are a suite of ocean products derived from the TBs that provide a 28-year record of wind speed, water vapor, cloud liquid, and rain rate; and 18 years (1997-2014) of sea surface temperatures, corresponding to the period for which 6 and/or 10 GHz measurements are available. Crucial to the inter-calibration and ocean product retrieval are a highly accurate radiative transfer model RTM. The RSS RTM has been continually refined for over 30 years and is arguably the most accurate model in the 1-100 GHz spectrum. The current generation of TB and ocean products, produced using the latest version of the RTM, is called Version-7. The accuracy of the Version-7 inter-calibration is estimated to be 0.1 K, based on inter-satellite comparisons and validation of the ocean products against in situ measurements. The data record produced by RSS has had a significant scientific impact. Over just the last 14 years (2000-2013) RSS data have been used in 743 peer-reviewed journal articles. This is an average of 4.5 peer-reviewed papers published every month made possible with RSS data. Some of the most important scientific contributions made by RSS data have been to the study of the climate. The AR5 Report "Climate Change 2013: The Physical Science Basis" by the Intergovernmental Panel on Climate Change (IPCC), the internationally accepted authority on climate change, references 20 peer-reviewed journal papers from RSS scientists. The report makes direct use of RSS water vapor data, RSS atmospheric temperatures from MSU/AMSU, and 9 other datasets that are derived from RSS data. The RSS TB data record is

  15. Genetic variation underlies temperature tolerance of embryos in the sea urchin Heliocidaris erythrogramma armigera.

    Science.gov (United States)

    Lymbery, R A; Evans, J P

    2013-10-01

    Ocean warming can alter natural selection on marine systems, and in many cases, the long-term persistence of affected populations will depend on genetic adaptation. In this study, we assess the potential for adaptation in the sea urchin Heliocidaris erythrogramma armigera, an Australian endemic, that is experiencing unprecedented increases in ocean temperatures. We used a factorial breeding design to assess the level of heritable variation in larval hatching success at two temperatures. Fertilized eggs from each full-sibling family were tested at 22 °C (current spawning temperature) and 25 °C (upper limit of predicted warming this century). Hatching success was significantly lower at higher temperatures, confirming that ocean warming is likely to exert selection on this life-history stage. Our analyses revealed significant additive genetic variance and genotype-by-environment interactions underlying hatching success. Consistent with prior work, we detected significant nonadditive (sire-by-dam) variance in hatching success, but additionally found that these interactions were modified by temperature. Although these findings suggest the potential for genetic adaptation, any evolutionary responses are likely to be influenced (and possibly constrained) by complex genotype-by-environment and sire-by-dam interactions and will additionally depend on patterns of genetic covariation with other fitness traits. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  16. Localized Temperature Variations in Laser-Irradiated Composites with Embedded Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    R. Brian Jenkins

    2017-01-01

    Full Text Available Fiber Bragg grating (FBG temperature sensors are embedded in composites to detect localized temperature gradients resulting from high energy infrared laser radiation. The goal is to detect the presence of radiation on a composite structure as rapidly as possible and to identify its location, much the same way human skin senses heat. A secondary goal is to determine how a network of sensors can be optimized to detect thermal damage in laser-irradiated composite materials or structures. Initial tests are conducted on polymer matrix composites reinforced with either carbon or glass fiber with a single optical fiber embedded into each specimen. As many as three sensors in each optical fiber measure the temporal and spatial thermal response of the composite to high energy radiation incident on the surface. Additional tests use a 2 × 2 × 3 array of 12 sensors embedded in a carbon fiber/epoxy composite to simultaneously measure temperature variations at locations on the composite surface and through the thickness. Results indicate that FBGs can be used to rapidly detect temperature gradients in a composite and their location, even for a direct strike of laser radiation on a sensor, when high temperatures can cause a non-uniform thermal response and FBG decay.

  17. Localized Temperature Variations in Laser-Irradiated Composites with Embedded Fiber Bragg Grating Sensors.

    Science.gov (United States)

    Jenkins, R Brian; Joyce, Peter; Mechtel, Deborah

    2017-01-27

    Fiber Bragg grating (FBG) temperature sensors are embedded in composites to detect localized temperature gradients resulting from high energy infrared laser radiation. The goal is to detect the presence of radiation on a composite structure as rapidly as possible and to identify its location, much the same way human skin senses heat. A secondary goal is to determine how a network of sensors can be optimized to detect thermal damage in laser-irradiated composite materials or structures. Initial tests are conducted on polymer matrix composites reinforced with either carbon or glass fiber with a single optical fiber embedded into each specimen. As many as three sensors in each optical fiber measure the temporal and spatial thermal response of the composite to high energy radiation incident on the surface. Additional tests use a 2 × 2 × 3 array of 12 sensors embedded in a carbon fiber/epoxy composite to simultaneously measure temperature variations at locations on the composite surface and through the thickness. Results indicate that FBGs can be used to rapidly detect temperature gradients in a composite and their location, even for a direct strike of laser radiation on a sensor, when high temperatures can cause a non-uniform thermal response and FBG decay.

  18. Climate variability of heat waves and their associated diurnal temperature range variations in Taiwan

    Science.gov (United States)

    Kueh, M.-T.; Lin, C.-Y.; Chuang, Y.-J.; Sheng, Y.-F.; Chien, Y.-Y.

    2017-07-01

    This study investigates heat waves in Taiwan and their maintenance mechanism, based upon observations and dynamically downscaled simulations. A 95th percentile threshold is used for identifying hot extremes over a period of consecutive days. Heat waves are forecast to become more severe in the future projection. Daily minimum temperatures are generally high and diurnal temperature ranges (DTR) are relatively large. The daily minimum temperature serves as the primary control in the variation in DTR during heat waves. An apparent increase in the daily minimum temperature suggests elevated heat stress at nighttime during future heat waves. Heat waves in Taiwan are associated with abnormal warming and drying atmospheric conditions under the control of an enhanced western North Pacific subtropical high. The surrounding waters serve as a vast moisture source to suppress the drying magnitude in the surface layer as the temperature rises, thereby ensuring a high humidity level during the hot spell. The subsidence and adiabatic warming above can trap the warm and humid air in the surface layer, leading to positive feedback to the abnormally hot surface condition. The associated warming and drying atmospheric conditions cover certain spatial extents, suggesting that the extreme situation identified here is not confined to just an island-wide hot spell; the abnormal hot weather can take place across a broad geographical area.

  19. Temperature-mediated survival, development and hatching variation of Pacific cod Gadus macrocephalus eggs.

    Science.gov (United States)

    Bian, X; Zhang, X; Sakrai, Y; Jin, X; Gao, T; Wan, R; Yamamoto, J

    2014-01-01

    Laboratory-validated data on the survival, development and hatching responses of fertilized Pacific cod Gadus macrocephalus eggs from the northern Japan stock were determined through an incubation experiment. The optimum temperature for survival until hatching ranged from 4 to 8°C. No significant difference in development rates was found between the populations from Mutsu Bay, Japan, and western Canadian coastal waters even though the samples may belong to different G. macrocephalus stocks. Gadus macrocephalus larvae hatched asynchronously from egg batches despite incubation under the same environment during their development. Both incubation temperature and temperature-mediated hatch rank affect size and yolk reserve. These data suggest that variations in water temperatures within an ecological range markedly influence the development rates, survival and hatching of the eggs, as well as the stage at hatch larvae of G. macrocephalus. Asynchronous hatching and the production of offspring with variable sizes and yolk reserves are considered evolutionary bet-hedging strategies that enable the species to maximize their likelihood of survival in an environment with variable temperatures. © 2013 The Fisheries Society of the British Isles.

  20. Seemingly divergent sea surface temperature proxy records in the central Mediterranean during the last deglaciation

    Directory of Open Access Journals (Sweden)

    M.-A. Sicre

    2013-06-01

    Full Text Available Sea surface temperatures (SSTs were reconstructed over the last 25 000 yr using alkenone paleothermometry and planktonic foraminifera assemblages from two cores of the central Mediterranean Sea: the MD04-2797 core (Siculo–Tunisian channel and the MD90-917 core (South Adriatic Sea. Comparison of the centennial scale structure of the two temperature signals during the last deglaciation period reveals significant differences in timing and amplitude. We suggest that seasonal changes likely account for seemingly proxy record divergences during abrupt transitions from glacial to interglacial climates and for the apparent short duration of the Younger Dryas (YD depicted by the alkenone time series, a feature that has already been stressed in earlier studies on the Mediterranean deglaciation.

  1. Changes in record-breaking temperature events in China and projections for the future

    Science.gov (United States)

    Deng, Hanqing; Liu, Chun; Lu, Yanyu; He, Dongyan; Tian, Hong

    2017-06-01

    As global warming intensifies, more record-breaking (RB) temperature events are reported in many places around the world where temperatures are higher than ever before http://cn.bing.com/dict/search?q=.&FORM=BDVSP6&mkt=zh-cn. The RB temperatures have caused severe impacts on ecosystems and human society. Here, we address changes in RB temperature events occurring over China in the past (1961-2014) as well as future projections (2006-2100) using observational data and the newly available simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The number of RB events has a significant multi-decadal variability in China, and the intensity expresses a strong decrease from 1961 to 2014. However, more frequent RB events occurred in mid-eastern and northeastern China over last 30 years (1981-2010). Comparisons with observational data indicate multi-model ensemble (MME) simulations from the CMIP5 model perform well in simulating RB events for the historical run period (1961-2005). CMIP5 MME shows a relatively larger uncertainty for the change in intensity. From 2051 to 2100, fewer RB events are projected to occur in most parts of China according to RCP 2.6 scenarios. Over the longer period from 2006 to 2100, a remarkable increase is expected for the entire country according to RCP 8.5 scenarios and the maximum numbers of RB events increase by approximately 600 per year at end of twenty-first century.

  2. Accuracy of recorded body temperature of critically ill patients related to measurement site: a prospective observational study.

    Science.gov (United States)

    Nonose, Y; Sato, Y; Kabayama, H; Arisawa, A; Onodera, M; Imanaka, H; Nishimura, M

    2012-09-01

    Accurate measurement of body temperature is an important indicator of the status of critically ill patients and is therefore essential. While axillary temperature is not considered accurate, it is still the conventional method of measurement in Asian intensive care units. There is uncertainty about the accuracy of thermometers for the critically ill. We compared the accuracy and precision of bladder, axillary and tympanic temperature measurements in critically ill patients. A total of 73 critically ill patients admitted to the intensive care unit of a teaching hospital were prospectively enrolled. Every four hours, we measured body temperature at three sites (bladder, axillary and tympanic). If the patient had received an indwelling pulmonary artery catheter, blood temperature was also recorded and this was compared with bladder, axillary and tympanic temperature readings. For all patients, axillary and tympanic temperature readings were compared with bladder temperature readings. Accuracy and precision were analysed using Bland-Altman analysis. When blood temperature data was available, the mean difference between blood and bladder temperature readings was small (0.02±0.21°C). Compared with bladder temperature, mean difference for axillary temperature was -0.33±0.55°C and for tympanic temperature it was -0.51±1.02°C. For critically ill patients, recorded axillary temperature was closer to bladder temperature than tympanic temperature.

  3. Phenology changes in the mayfly Ephemera danica in response to water temperature variations in the River Dove, UK

    Science.gov (United States)

    Johnson, Matthew; Everall, Nicholas; Wilby, Robert

    2015-04-01

    Water temperature in rivers is critical to aquatic life. Climate and environmental change can elevate river temperatures to levels that stress fish, but impacts on other aquatic organisms are not well understood. In particular, rising temperatures are expected to alter the phenology of aquatic insects at levels substantially below those required to stress fish species. The phenology of the mayfly Ephemera danica, a large burrowing species that is widespread throughout Europe, is known to be sensitive to temperature change. To assess the temporal and spatial variability in mayfly emergence, E. danica were monitored at two reaches in the River Dove, English Peak District over the period 2007 to 2013. Variations in Growing Degree Days (GDDs) were modelled for an upstream site with an annual temperature range in excess of 15 ° C (Beresford Dale) and a downstream site, dominated by near constant discharges of cool groundwater with an annual range less than 8 ° C (Dovedale). The emergence of E. danica was strongly related to GDDs at each site. E. danica usually remains in an aquatic larval stage for two years before emerging in its adult, terrestrial form. However, after particularly warm summers in Beresford Dale, E. danica was recorded to emerge after only one year in its aquatic form. Following the particularly wet/cold year of 2012, E. danica began to revert back to a bi-annual cycle. In Dovedale, an average of 374 fewer GDDs were accumulated in comparison to Beresford Dale. As a result, E. danica maintained a two-year growth cycle throughout the monitoring period despite the phenology changes observed 8 km upstream at Beresford. Changes to insect phenology are significant because populations with a one-year cycle are potentially more vulnerable to adverse weather when the majority of the population is in terrestrial form. Also, altering the growth, development and size of insects affects reproductive success with implications for population dynamics. Data from the

  4. Development of a method to compensate for signal quality variations in repeated auditory event-related potential recordings

    Directory of Open Access Journals (Sweden)

    Antti K O Paukkunen

    2010-03-01

    Full Text Available Reliable measurements are mandatory in clinically relevant auditory event-related potential (AERP-based tools and applications. The comparability of the results gets worse as a result of variations in the remaining measurement error. A potential method is studied that allows optimization of the length of the recording session according to the concurrent quality of the recorded data. In this way, the sufficiency of the trials can be better guaranteed, which enables control of the remaining measurement error. The suggested method is based on monitoring the signal-to-noise ratio (SNR and remaining measurement error which are compared to predefined threshold values. The SNR test is well defined, but the criterion for the measurement error test still requires further empirical testing in practice. According to the results, the reproducibility of average AERPs in repeated experiments is improved in comparison to a case where the number of recorded trials is constant. The test-retest reliability is not significantly changed on average but the between-subject variation in the value is reduced by 33-35%. The optimization of the number of trials also prevents excessive recordings which might be of practical interest especially in the clinical context. The efficiency of the method may be further increased by implementing online tools that improve data consistency.

  5. Development of a Method to Compensate for Signal Quality Variations in Repeated Auditory Event-Related Potential Recordings

    Science.gov (United States)

    Paukkunen, Antti K. O.; Leminen, Miika M.; Sepponen, Raimo

    2010-01-01

    Reliable measurements are mandatory in clinically relevant auditory event-related potential (AERP)-based tools and applications. The comparability of the results gets worse as a result of variations in the remaining measurement error. A potential method is studied that allows optimization of the length of the recording session according to the concurrent quality of the recorded data. In this way, the sufficiency of the trials can be better guaranteed, which enables control of the remaining measurement error. The suggested method is based on monitoring the signal-to-noise ratio (SNR) and remaining measurement error which are compared to predefined threshold values. The SNR test is well defined, but the criterion for the measurement error test still requires further empirical testing in practice. According to the results, the reproducibility of average AERPs in repeated experiments is improved in comparison to a case where the number of recorded trials is constant. The test-retest reliability is not significantly changed on average but the between-subject variation in the value is reduced by 33–35%. The optimization of the number of trials also prevents excessive recordings which might be of practical interest especially in the clinical context. The efficiency of the method may be further increased by implementing online tools that improve data consistency. PMID:20407635

  6. Model-assisted analysis of spatial and temporal variations in fruit temperature and transpiration highlighting the role of fruit development.

    Directory of Open Access Journals (Sweden)

    Thibault Nordey

    Full Text Available Fruit physiology is strongly affected by both fruit temperature and water losses through transpiration. Fruit temperature and its transpiration vary with environmental factors and fruit characteristics. In line with previous studies, measurements of physical and thermal fruit properties were found to significantly vary between fruit tissues and maturity stages. To study the impact of these variations on fruit temperature and transpiration, a modelling approach was used. A physical model was developed to predict the spatial and temporal variations of fruit temperature and transpiration according to the spatial and temporal variations of environmental factors and thermal and physical fruit properties. Model predictions compared well to temperature measurements on mango fruits, making it possible to accurately simulate the daily temperature variations of the sunny and shaded sides of fruits. Model simulations indicated that fruit development induced an increase in both the temperature gradient within the fruit and fruit water losses, mainly due to fruit expansion. However, the evolution of fruit characteristics has only a very slight impact on the average temperature and the transpiration per surface unit. The importance of temperature and transpiration gradients highlighted in this study made it necessary to take spatial and temporal variations of environmental factors and fruit characteristics into account to model fruit physiology.

  7. An alternative method to record rising temperatures during dental implant site preparation: a preliminary study using bovine bone

    Directory of Open Access Journals (Sweden)

    Domenica Laurito

    2010-12-01

    Full Text Available Overheating is constantly mentioned as a risk factor for bone necrosis that could compromise the dental implant primary stability. Uncontrolled thermal injury can result in a fibrous tissue, interpositioned at the implant-bone interface, compromising the long-term prognosis. The methods used to record temperature rise include either direct recording by thermocouple instruments or indirect estimating by infrared thermography. This preliminary study was carried out using bovine bone and a different method of temperatures rising estimation is presented. Two different types of drills were tested using fluoroptic thermometer and the effectiveness of this alternative temperature recording method was evaluated.

  8. One hundred years of Arctic surface temperature variation due to anthropogenic influence

    Science.gov (United States)

    Fyfe, John C.; von Salzen, Knut; Gillett, Nathan P.; Arora, Vivek K.; Flato, Gregory M.; McConnell, Joseph R.

    2013-01-01

    Observations show that Arctic-average surface temperature increased from 1900 to 1940, decreased from 1940 to 1970, and increased from 1970 to present. Here, using new observational data and improved climate models employing observed natural and anthropogenic forcings, we demonstrate that contributions from greenhouse gas and aerosol emissions, along with explosive volcanic eruptions, explain most of this observed variation in Arctic surface temperature since 1900. In addition, climate model simulations without natural and anthropogenic forcings indicate very low probabilities that the observed trends in each of these periods were due to internal climate variability alone. Arctic climate change has important environmental and economic impacts and these results improve our understanding of past Arctic climate change and our confidence in future projections. PMID:24025852

  9. Amorphous to nanocrystalline transition in HWCVD Si:H films by substrate temperature variation

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, Purabi; Jha, Himanshu S.; Agarwal, Pratima [Department of Physics, IIT Guwahati, Guwahati (India); Deva, Dinesh [Department of Chemical Engineering, IIT Kanpur, Kanpur (India)

    2010-04-15

    Thin films of hydrogenated silicon with band gap ranging from 2.0-2.34 eV are prepared at deposition rate 8-14A/sec in an indigenously fabricated HWCVD system keeping all parameters except substrate temperature fixed. The films grown at T{sub s}{<=}150 C are found to be pure amorphous, whereas the formation of nanocrystalline phase starts at T{sub s} {>=} 200 C. With increase in T{sub s}, crystalline fraction increases along with the increase in the band gap whereas the hydrogen content in the films and the deposition rate decreases. The variation of microstructure by varying substrate temperature without a significant decrease in deposition rate is useful for various device applications. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Constraining past seawater δ18O and temperature records developed from foraminiferal geochemistry

    Science.gov (United States)

    Quinn, T. M.; Thirumalai, K.; Marino, G.

    2016-12-01

    Paired measurements of magnesium-to-calcium ratios (Mg/Ca) and the stable oxygen isotopic composition (δ18O) in foraminifera have significantly advanced our knowledge of the climate system by providing information on past temperature and seawater δ18O (δ18Osw, a proxy for salinity and ice volume). However, multiple sources of uncertainty exist in transferring these downcore geochemical data into quantitative paleoclimate reconstructions. Here, we develop a computational toolkit entitled Paleo-Seawater Uncertainty Solver (PSU Solver) that performs bootstrap Monte Carlo simulations to constrain these various sources of uncertainty. PSU Solver calculates temperature and δ18Osw, and their respective confidence intervals using an iterative approach with user-defined errors, calibrations, and sea-level curves. Our probabilistic approach yields reduced uncertainty constraints compared to theoretical considerations and commonly used propagation exercises. We demonstrate the applicability of PSU Solver for published records covering three timescales: the late Holocene, the last deglaciation, and the last glacial period. We show that the influence of salinity on Mg/Ca can considerably alter the structure and amplitude of change in the resulting reconstruction and can impact the interpretation of paleoceanographic time series. We also highlight the sensitivity of the records to various inputs of sea-level curves, transfer functions, and uncertainty constraints. PSU Solver offers an expeditious yet rigorous approach to test the robustness of past climate variability inferred from paired Mg/Ca-δ18O measurements.

  11. Evidence for cosmic ray modulation in temperature records from the South Atlantic Magnetic Anomaly region

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, E. [Sao Paulo Univ. (Brazil). Dept. de Geofisica; Federal do Pampa Univ., Cacapava do Sul (Brazil); Pacca, I.G. [Sao Paulo Univ. (Brazil). Dept. de Geofisica; Pereira-Filho, A.J. [Sao Paulo Univ. (Brazil). Dept. de Ciencias Atmosfericas; Rampelloto, P.H. [Federal do Pampa Univ., Sao Gabriel (Brazil); Rigozo, N.R. [Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos (Brazil). Div. de Geofisica Espacial

    2013-11-01

    Possible direct or indirect climatic effects related to solar variability and El Nino-Southern Oscillation (ENSO) were investigated in the southern Brazil region by means of the annual mean temperatures from four weather stations 2 degrees of latitude apart over the South Atlantic Magnetic Anomaly (SAMA) region. Four maximum temperature peaks are evident at all stations in 1940, 1958, 1977 and 2002. A spectral analysis indicates the occurrence of periodicities between 2 and 7 yr, most likely associated with ENSO, and periodicities of approximately 11 and 22 yr, normally associated with solar variability. Cross-wavelet analysis indicated that the signal associated with the 22 yr solar magnetic cycle was more persistent in the last decades, while the 11 yr sunspot cycle and ENSO periodicities were intermittent. Phase-angle analysis revealed that temperature variations and the 22 yr solar cycle were in anti-phase near the SAMA center. Results show an indirect indication of possible relationships between the variability of galactic cosmic rays and climate change on a regional scale.

  12. The effect of temperature and pH variations on the surface tension of EDTA solutions.

    Science.gov (United States)

    Yılmaz, Zeliha; Aktemur, Sevinc; Buzoglu, Hatice Dogan; Gümüsderelioglu, Menemse

    2011-06-01

    Surface tension of a liquid is one of the major factors that affect the wetting of a solid. The reduction in surface tension could improve the contact of irrigants with the dentinal walls of the root canal system. This in vitro study was conducted to evaluate the effect of pH and temperature variations on the surface tension of EDTA solutions. Three solutions, 17% EDTA, REDTA, and EDTA-T, were prepared and adjusted to have a pH of 5.5, 7.5, and 10.5. The surface tension of the test solutions was measured at 22 °C by the pendant drop technique, and the measurement was repeated after heating the solution at 37 °C. Differences among the experimental groups were statistically analyzed using three-way analysis of variance followed by the Bonferroni test for pair-wise comparison. The results of this study showed that there were significant differences in the surface tension values of solutions depending on the pH and temperature (P surface tension level of the EDTA solution dramatically decreased when surfactant was added to the EDTA solution in both pH and temperature variations (P surface tension value at a pH of 5.5 of all EDTA solutions, at a pH of 7.5 of EDTA and REDTA solutions, and at a pH of 10.5 of only REDTA solution (P surface tension of EDTA with and without surfactant is influenced by pH and temperature. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. The Effects of Cells Temperature Increment and Variations of Irradiation for Monocrystalline Photovoltaic

    Science.gov (United States)

    Fuad Rahman Soeharto, Faishal; Hermawan

    2017-04-01

    Photovoltaic cell technology has been developed to meet the target of 17% Renewable Energy in 2025 accordance with Indonesia Government Regulation No. 5 2006. Photovoltaic cells are made of semiconductor materials, namely silicon or germanium (p-n junction). These cells need the light that comes from solar irradiation which brings energy photons to convert light energy into electrical energy. It is different from the solar heater that requires heat energy or thermal of sunlight that is normally used for drying or heating water. Photovoltaic cells requires energy photons to perform the energy conversion process, the photon energy can be derived from sunlight. Energy photon is taken from the sun light along with the advent of heat due to black-body radiation, which can lead to temperature increments of photovoltaic cells. Increment of 1°C can decreased photovoltaic cell voltage of up to 2.3 mV per cell. In this research, it will be discuss the analysis of the effect of rising temperatures and variations of irradiation on the type monocrystalline photovoltaic. Those variation are analyzed, simulated and experiment by using a module of experiment. The test results show that increment temperature from 25° C to 80° C at cell of photovoltaic decrease the output voltage of the photovoltaic cell at 4.21 V, and it also affect the power output of the cell which decreases up to 0.7523 Watt. In addition, the bigger the value of irradiation received by cell at amount of 1000 W / m2, produce more output power cells at the same temperature.

  14. Pathfinder Version 5.3 AVHRR Sea Surface Temperature Climate Data Record

    Science.gov (United States)

    Baker-Yeboah, S.; Kilpatrick, K. A.

    2016-12-01

    Long-term, climate data records of global sea surface temperature (SST) are important for ocean and climate variability studies. The NOAA National Centers for Environmental Information process, maintain, and continue development of the long-term, Pathfinder climate data record of global SST. These SST values are generated at approximately a 4 km resolution using a consistent algorithm for Advanced Very High Resolution Radiometer (AVHRR) instruments aboard NOAA polar-orbiting satellites dating back to 1981. A new version of the Pathfinder SST products, version 5.3, has recently been produced for a thirty three year period (1981 - 2014). This latest reprocessing used an Amazon Web Service cloud system and a modernized version of the heritage Pathfinder SST codes integrated into the open source NASA SeaWiFS Data Analysis System (SeaDAS6.4). Coefficients for this SST product were generated using regression analyses with co-located in situ and satellite measurements. Validation results corresponding to Pathfinder Level 3 skin SST minus sub-surface buoy SST show a global mean difference of -0.2 K with a standard deviation of 0.5 K. New quality control procedures for the new version of Pathfinder SST Climate Data Record products will be presented along with other improvements made in comparison to previous versions of Pathfinder SST.

  15. Marine sediments and Beryllium-10 record of the geomagnetic moment variations of the 20-50ka interval

    Science.gov (United States)

    Ménabréaz, L.; Thouveny, N.; Bourles, D. L.

    2012-12-01

    To better constrain the Earth's dipole moment changes at the time of the Laschamp and Mono Lake excursions, we reconstructed the cosmogenic nuclide 10Be production variations in the atmosphere using authigenic 10Be/9Be records measured along two marine sediment sequences from the north-east Atlantic (Portuguese margin) and west-equatorial Pacific (Papua-New Guinea margin) oceans. These two records evidence an almost doubling of the 10Be production at ~41 ka, thus assignable to the geomagnetic dipole low associated to the Laschamp excursion. The compilation of authigenic 10Be/9Be marine records provides a stack which indicates that the global 10Be production rates at 41 ka were enhanced by a ~1.5 factor compared to the average over the 20-50 ka interval. The comparison of this authigenic 10Be/9Be marine stack with the Greenland 10Be flux record (smoothed by 1000-year averaging) evidences a good coherency of the timing and amplitude of 10Be production recorded at high, mid and low latitudes. This confirms that the 10Be overproduction signal has a global significance, as expected from a geomagnetic dipole moment loss. The calibration of the 10Be/9Be stack using absolute virtual dipole moment values provides an independent tool to reconstruct geomagnetic dipole moment variations. This allows computing the loss rate leading to the Laschamp dipole minimum (~ -1.5 x 1022 A.m2.ka-1), which constitutes an interesting criterion to assess the loss rate of the historical field. In constrast with relative paleointensity records and absolute paleointensity data sets, the absence of significant cosmogenic enhancement at the age of 34 ka suggests that the Mono Lake dipole low was not sufficient to trigger a significant cosmogenic overproduction. This demonstrates that if the Mono lake excursion really occurred at that time, the duration and amplitude of the dipole weakening were very limited compared to that of the Laschamp. The 10Be overproduction quantified in this study

  16. Validation of the Suomi NPP VIIRS Ice Surface Temperature Environmental Data Record

    Directory of Open Access Journals (Sweden)

    Yinghui Liu

    2015-12-01

    Full Text Available Continuous monitoring of the surface temperature is critical to understanding and forecasting Arctic climate change; as surface temperature integrates changes in the surface energy budget. The sea-ice surface temperature (IST has been measured with optical and thermal infrared sensors for many years. With the IST Environmental Data Record (EDR available from the Visible Infrared Imaging Radiometer Suite (VIIRS onboard the Suomi National Polar-orbiting Partnership (NPP and future Joint Polar Satellite System (JPSS satellites; we can continue to monitor and investigate Arctic climate change. This work examines the quality of the VIIRS IST EDR. Validation is performed through comparisons with multiple datasets; including NASA IceBridge measurements; air temperature from Arctic drifting ice buoys; Moderate Resolution Imaging Spectroradiometer (MODIS IST; MODIS IST simultaneous nadir overpass (SNO; and surface air temperature from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR reanalysis. Results show biases of −0.34; −0.12; 0.16; −3.20; and −3.41 K compared to an aircraft-mounted downward-looking pyrometer; MODIS; MODIS SNO; drifting buoy; and NCEP/NCAR reanalysis; respectively; root-mean-square errors of 0.98; 1.02; 0.95; 4.89; and 6.94 K; and root-mean-square errors with the bias removed of 0.92; 1.01; 0.94; 3.70; and 6.04 K. Based on the IceBridge and MODIS results; the VIIRS IST uncertainty (RMSE meets or exceeds the JPSS system requirement of 1.0 K. The product can therefore be considered useful for meteorological and climatological applications.

  17. Viscosity of water-in-oil emulsions. Variation with temperature and water volume fraction

    Energy Technology Data Exchange (ETDEWEB)

    Farah, Marco A.; Caldas, Jorge Navaes [Petroleo Brasileiro S.A., Rua General Canabarro, 500, Maracana, Rio, CEP 2057-900 (Brazil); Oliveira, Roberto C. [Petroleo Brasileiro S.A., Cenpes, Cidade Universitaria (Brazil); Rajagopal, Krishnaswamy [LATCA-Laboratorio de Termodinamica e Cinetica Aplicada-Escola de Quimica, Departamento de Engenharia Quimica, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitaria, C.P. 68452, CEP 21949-900, Rio de Janeiro (Brazil)

    2005-09-15

    Water-in-oil emulsions are important in the petroleum industry in production operations, where the water content of the emulsion can be as high as 60% in volume, also in petroleum refining operations where generally the water content is low. The effective viscosity of water-in-oil emulsions depends mainly on the volume fraction of dispersed phase and temperature, along with several minor effects, such as shear rate, average droplet size, droplet size distribution, viscosity and density of oil. Using six different crude oils, the effective viscosities of several synthetic water-in-oil emulsions are measured at atmospheric pressure using a dynamic viscosimeter for different shear rates, temperatures and volume fractions of the dispersed phase. The ASTM equation, method D-341, for describing viscosity as a function of temperature is extended to include the variation of dispersed phase volume fraction. The proposed equation gives good correlation between the measured viscosities of water-in-oil emulsions as a function of temperature and the volume fraction of water.

  18. A Fundamental Climate Data Record of Intercalibrated Brightness Temperature Data from SSM/I and SSMIS

    Science.gov (United States)

    Sapiano, M. R. P.; Berg, W. K.; McKague, D.; Kummerow, C. D.

    2012-04-01

    The first Special Sensor Microwave/Imager (SSM/I) was launched in June 1987 on the Defense Meteorological Satellite Program's (DMSP) F08 spacecraft and started what is now a nearly continuous 24-year record of passive microwave imager data that can be used to monitor the climate system. This includes such fields as precipitation (over both land and ocean), the extent of sea ice and snow, sea ice concentration, total precipitable water, cloud liquid water, and surface wind speed over oceans. A total of nine window channel radiometers have been launched to date in the DMSP series including the SSM/I instrument on board F08, F10, F11, F13, F14, and F15 followed by the Special Sensor Microwave Imager/Sounder (SSMIS) on board F16, F17, and F18, which is expected to operate for at least the next decade. As a result, this data record provides the best available source of long-term global observations of several hydrological variables for climate applications. Although the DMSP sensors provide a long-term record, because the sensors were developed for operational use there are a number of issues that must be addressed to produce a dataset suitable for use in climate applications. There are a several quality control and calibration issues including, but not limited to, quality control of the original antenna temperatures, geolocation, cross-track bias corrections, solar and lunar intrusion issues and emissive antennas. The goal of producing an FCDR of brightness temperature data involves not only addressing many of these instrument issues, but also developing a well-documented, transparent approach that allows for subsequent improvements as well as a framework for incorporating future sensors. Once the data have been quality controlled and various calibration corrections have been applied, the goal is to adjust the calibration of the various sensors so that they are physically consistent. Such intercalibration does not correct for changes due to local observing time, which

  19. To what extent do water isotope records from low accumulation Alpine ice cores reproduce instrumental temperature series?

    Directory of Open Access Journals (Sweden)

    Pascal Bohleber

    2013-04-01

    Full Text Available Among Alpine ice core drilling sites, the Colle Gnifetti glacier saddle situated in the Monte Rosa summit range is the only one whose net snow accumulation rate is low enough to offer climate records back to some 1000 yr. It is demonstrated that the strong snow erosion at this site particularly hampers the interpretation of stable water isotope records δ18O, δD in terms of atmospheric temperature changes. We evaluate the δ18O records from four Colle Gnifetti cores for their common variability to extract a composite isotope record that may be compared with the instrumental temperature evidence. Time series analyses over the last 120 yr reveal that the common δ18O signal is mainly reflected in the low frequency variability, starting at the decadal scale. Comparing the correspondingly smoothed composite record to the high-elevation temperature time series (specifically adjusted to the seasonality of the net snow accumulation reveals the following findings: On the decadal scale, the isotope variability correlates with the temperature record at around R=0.65 but is interrupted by three, ca. 10-yr long mismatch periods. The multidecadal isotope signal closely reflects the strong overall 20th century temperature increase, thereby showing an up to three-fold higher isotope temperature sensitivity than commonly assumed. Over the entire instrumental period back to 1760, five more such mismatch periods are embedded in the generally coherent pattern of the δ18O and instrumental temperature records (including the strong overestimate of the temperature around 1850 by the isotope temperature proxy. For the early instrumental period (1890–1760 characterized by a comparably weak long-term temperature trend, the isotope signal generally suggests warmer conditions of about 0.4°C compared to instrumental data.

  20. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature (LST) Environmental Data Record (EDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of Land Surface Temperature (LST) from the Visible Infrared Imaging Radiometer Suite...

  1. NOAA Climate Data Record (CDR) of SSM/I and SSMIS Microwave Brightness Temperatures, RSS Version 7

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Version 7 NOAA Fundamental Climate Data Record (CDR) from Remote Sensing Systems (RSS) contains brightness temperatures that have been inter-calibrated and...

  2. NOAA Climate Data Record (CDR) of SSM/I and SSMIS Microwave Brightness Temperatures, CSU Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) from Colorado State University (CSU) contains brightness temperatures that have been improved and quality-controlled over the...

  3. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Ice Concentration and Ice Surface Temperature Environmental Data Records (EDRs) from NDE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of Sea Ice Concentration (SIC) and Ice Surface Temperature (IST) from the Visible...

  4. NOAA Climate Data Record (CDR) of Advanced Microwave Sounding Unit (AMSU)-A Brightness Temperature, Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Climate Data Record (CDR) for Advanced Microwave Sounding Unit-A (AMSU-A) brightness temperature in "window channels". The data cover a time period from...

  5. Analysis of geomagnetic storm variations and count-rate of cosmic ray muons recorded at the Brazilian southern space observatory

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, Everton [University of Sao Paulo, USP, Institute of Astronomy, Geophysics and Atmospheric Sciences, IAG/USP, Department of Geophysics, Sao Paulo, SP (Brazil); Savian, Jairo Francisco [Space Science Laboratory of Santa Maria, LACESM/CT, Southern Regional Space Research Center, CRS/INPE, MCT, Santa Maria, RS (Brazil); Silva, Marlos Rockenbach da; Lago, Alisson dal; Trivedi, Nalin Babulal [National Institute for Space Research, INPE/MCT, Division of Space Geophysics, DGE, Sao Jose dos Campos, SP (Brazil); Schuch, Nelson Jorge, E-mail: efrigo@iag.usp.br, E-mail: savian@lacesm.ufsm.br, E-mail: njschuch@lacesm.ufsm.br, E-mail: marlos@dge.inpe.br, E-mail: dallago@dge.inpe.br, E-mail: trivedi@dge.inpe.br [Southern Regional Space Research Center, CRS/INPE, MCT, Santa Maria, RS (Brazil)

    2007-07-01

    An analysis of geomagnetic storm variations and the count rate of cosmic ray muons recorded at the Brazilian Southern Space Observatory -OES/CRS/INPE-MCT, in Sao Martinho da Serra, RS during the month of November 2004, is presented in this paper. The geomagnetic measurements are done by a three component low noise fluxgate magnetometer and the count rates of cosmic ray muons are recorded by a muon scintillator telescope - MST, both instruments installed at the Observatory. The fluxgate magnetometer measures variations in the three orthogonal components of Earth magnetic field, H (North-South), D (East-West) and Z (Vertical), with data sampling rate of 0.5 Hz. The muon scintillator telescope records hourly count rates. The arrival of a solar disturbance can be identified by observing the decrease in the muon count rate. The goal of this work is to describe the physical morphology and phenomenology observed during the geomagnetic storm of November 2004, using the H component of the geomagnetic field and vertical channel V of the multi-directional muon detector in South of Brazil. (author)

  6. A 17,000 yr paleomagnetic secular variation record from the southeast Alaskan margin: Regional and global correlations

    Science.gov (United States)

    Walczak, M. H.; Stoner, J. S.; Mix, A. C.; Jaeger, J.; Rosen, G. P.; Channell, J. E. T.; Heslop, D.; Xuan, C.

    2017-09-01

    High-resolution sedimentary records on two cores from the Gulf of Alaska margin allow development of a ∼17,400-yr reconstruction of paleomagnetic secular variation (PSV). General agreement between the two records on their independent chronologies confirms that local PSV is recorded, demonstrating that such archives, notwithstanding complexities due to variable sedimentary regimes, deposition rates, and diagenetic conditions, provide meaningful information on past changes of the geomagnetic field. Comparisons with other independently dated sedimentary paleomagnetic records from the NE Pacific indicate largely coherent inclination records that in combination create a NE Pacific sedimentary inclination anomaly stack (NEPSIAS) capturing the common signal over an area spanning >30° longitude and latitude from Alaska through Oregon to Hawaii. Comparisons of NEPSIAS with high quality declination records from the northern North Atlantic (NNA) show that negative (shallow) inclination anomalies in NEPSIAS are associated with eastward NNA declinations while positive (steep) inclination anomalies in NEPSIAS are associated with westward NNA declinations. Comparison of these directional records to regional geomagnetic intensities over the past ∼3000 yrs in North America and back nearly 8000 yrs in the Euro/Mediterranean region, are consistent with a driving mechanism of oscillations in the relative strength of the North American and Euro/Mediterranean flux lobes. The persistence of these dynamics through the Holocene implicates a long-lived organizing structure likely imposed on the geomagnetic field by the lower mantle and/or inner core. These observations underscore a fundamental connection between directional PSV in the North Pacific with that of the North Atlantic, supporting the potential for long-distance correlation of directional PSV as a chronostratigraphic tool.

  7. Late Quaternary paleomagnetic secular variation recorded in deep-sea sediments from the Demerara Rise, equatorial west Atlantic Ocean

    Science.gov (United States)

    Lund, Steve; Oppo, Delia; Curry, William

    2017-11-01

    We have carried out a paleomagnetic/rock magnetic study of two gravity cores and two multicores from the Demerara Rise (∼8°N), adjacent to NE South America. The magnetic measurements indicate that there is a stable natural remanent magnetization (NRM) carried primarily by detrital magnetite/titanomagnetite that preserves the local pattern of paleomagnetic secular variation (PSV). The two gravity cores have consistent patterns of directional variability. The rock magnetic intensities in both gravity cores vary by less than a factor of three. Relative paleointensity estimates have been derived by normalizing the NRM to Chi, ARM, and SIRM. Both gravity cores show the same pattern of relative paleointensity variability. 27 calibrated radiocarbon dates from our studied gravity cores and one additional piston core (Huang et al., 2014) have been used to build chronologies for the two gravity cores. Core 25GGC has bulk sedimentation rates varying from 18 to 22 cm/ky and contains a PSV record for the last 19 ka; core 9GGC has bulk sedimentation rates of 9-17 cm/ky and contains a PSV record for the last 28 ka. There are no other published, good-quality, well-dated full-vector PSV records within 4000 km of the sites, a region which constitutes almost 20% of the Earth's surface area. Our relative paleointensity records are consistent with other global records under the assumption of field intensity being largely a global-scale process. We have compared our directional PSV data statistically with eight other good-quality, well-dated low-latitude PSV records. Our statistical analysis shows that our Demerara Rise directional PSV records are consistent with those other studies and that the Late Quaternary Equatorial field variability is significantly lower than much longer-duration (780 ka to 5 Ma) variability.

  8. Variations in seawater Sr/Ca recorded in deep-sea bamboo corals

    Science.gov (United States)

    Hill, T. M.; Lavigne, M.; Spero, H. J.; Guilderson, T.; Gaylord, B.; Clague, D.

    2012-09-01

    A depth transect of deep-sea bamboo corals along the California margin provides evidence that coral strontium to calcium ratios (Sr/Cacoral) record seawater Sr/Ca ratios (Sr/Casw). A calibration was constructed utilizing Sr/Cacoral ratios and previously published Pacific Sr/Casw data (R2 = 0.53, n = 12, p < 0.01): Sr/Cacoral (mmol/mol) = 4.62*Sr/Casw (mmol/mol) - 36.64. Sr/Casw is ultimately governed by the remineralization of Sr-containing shells of surface water-derived marine organisms (e.g., Acantharia) at intermediate water depths. California margin Sr/Cacoral records from 792 and 1295 m document fluctuations in Sr/Casw that appear decadal-scale. These results suggest that Sr/Casw may not be as stable as previously assumed and may be influenced by surface productivity on short timescales.

  9. Variations in the temperature sensitivity of spring leaf phenology from 1978 to 2014 in Mudanjiang, China

    Science.gov (United States)

    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.

  10. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  11. Lipid accumulation in response to nitrogen limitation and variation of temperature in Nannochloropsis salina.

    Science.gov (United States)

    Fakhry, Eman M; El Maghraby, Dahlia M

    2015-12-01

    This batch study deals with the relation between lipid as well as triglyceride contents in Nannochloropsis salina and variation in culture conditions such as nitrogen concentration and temperature. The tested parameters caused reduction in growth expressed as cell count, optical density and dry weight, as well strongly involved in lipids and triglycerides accumulation and significantly affected the lipid productivity. At the beginning of the work, the concentration of nitrogen in the medium was reduced to three quarter, half and quarter of the original f2 medium while the temperature kept constant. After that, the optimal nitrogen concentration (quarter of the original media) giving high lipid yield was tested with different temperature degrees from 15 to 35°C with five degree intervals. Although the growth was insignificantly influenced, a considerable increase in lipid and triglyceride (56.1 and 15.1% of dry weight respectively) was observed when the concentration of nitrogen in the medium was reduced to the quarter. Moreover, 59.3% lipid and 17.1% triglyceride on the basis of dry weight were obtained by the combination of 25% nitrogen concentration and 30°C. Simple regressions recommended that the interaction effect of nitrogen limitation and temperature on lipid and triglyceride accumulation was not as fundamental as for nitrogen limitation stress. The degree of nitrogen availability in the combination of temperature effect has been identified as the critical determinant for the maximal production of lipid in N. salina. Nevertheless, major advances in this field can be considered by studying more stresses techniques and genetic strategies.

  12. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  13. Evaluation of empirical mode decomposition for quantifying multi-decadal variations in sea level records

    Science.gov (United States)

    Chambers, D. P.

    2014-12-01

    The ability of empirical mode decomposition (EMD) to extract multidecadal variability from sea level records is tested using three simulations: one based on a series of purely sinusoidal modes, one based on scaled climate indices of El Niño and the Pacific Decadal Oscillation (PDO), and the final one including a single month with an extreme sea level event. All simulations include random noise of similar variance to high-frequency variability in the San Francisco tide gauge record. The intrinsic mode functions (IMFs) computed using EMD were compared to the prescribed oscillations. In all cases, the longest-period modes are significantly distorted, with incorrect amplitudes and phases. This affects the estimated acceleration computed from the longest periodic IMF. In these simulations, the acceleration was underestimated in the case with purely sinusoidal modes, and overestimated by nearly 100% in the case with prescribed climate modes. Additionally, in all cases, extra low-frequency modes uncorrelated with the prescribed variability are found. These experiments suggest that using EMD to identify multidecadal variability and accelerations in sea level records should be used with caution.

  14. Molecular records of continental air temperature and monsoon precipitation variability in East Asia spanning the past 130,000 years

    NARCIS (Netherlands)

    Peterse, F.|info:eu-repo/dai/nl/371172314; Martínez-García, A.; Zhou, B.; Beets, C.J.; Prins, M.A.; Zheng, H.; Eglinton, T.I.

    2014-01-01

    Our current understanding of past changes in East Asian summer monsoon (EASM) precipitation intensity derives from several loess–paleosol sequences and oxygen isotope (δ18O) records of well-dated stalagmites. Although temperature is generally presumed to have had minimal impact on EASM records, past

  15. Coral record of southeast Indian Ocean marine heatwaves with intensified Western Pacific temperature gradient

    Science.gov (United States)

    Zinke, J.; Hoell, A.; Lough, J. M.; Feng, M.; Kuret, A. J.; Clarke, H.; Ricca, V.; Rankenburg, K.; McCulloch, M. T.

    2015-10-01

    Increasing intensity of marine heatwaves has caused widespread mass coral bleaching events, threatening the integrity and functional diversity of coral reefs. Here we demonstrate the role of inter-ocean coupling in amplifying thermal stress on reefs in the poorly studied southeast Indian Ocean (SEIO), through a robust 215-year (1795-2010) geochemical coral proxy sea surface temperature (SST) record. We show that marine heatwaves affecting the SEIO are linked to the behaviour of the Western Pacific Warm Pool on decadal to centennial timescales, and are most pronounced when an anomalously strong zonal SST gradient between the western and central Pacific co-occurs with strong La Niña's. This SST gradient forces large-scale changes in heat flux that exacerbate SEIO heatwaves. Better understanding of the zonal SST gradient in the Western Pacific is expected to improve projections of the frequency of extreme SEIO heatwaves and their ecological impacts on the important coral reef ecosystems off Western Australia.

  16. Distribution and morphological variation of Eleutherodactylus mercedesae Lynch & McDiarmid, 1987 (Amphibia, Anura, Leptodactylidae) with first record for Peru

    Science.gov (United States)

    Padial, J.M.; McDiarmid, R.; De la Riva, I.

    2006-01-01

    We report new distributional information for Eleutherodactylus mercedesae in Bolivia, and provide the first record for Peru based on an adult female. This species, previously endemic to Bolivia, now ranges across about 1000 km in cloud forests on the Amazonian slopes of the Andes from southern Peru to central Bolivia. We provide the first morphological description of females based on two specimens, compare them with the male type and paratype, add some observations to the original description, and comment on variation in the species.

  17. Denali Ice Core Record of North Pacific Sea Surface Temperatures and Marine Primary Productivity

    Science.gov (United States)

    Polashenski, D.; Osterberg, E. C.; Kreutz, K. J.; Winski, D.; Wake, C. P.; Ferris, D. G.; Introne, D.; Campbell, S. W.

    2016-12-01

    Chemical analyses of precipitation preserved in glacial ice cores provide a unique opportunity to study changes in atmospheric circulation patterns and ocean surface conditions through time. In this study, we aim to investigate changes in both the physical and biological parameters of the north-central Pacific Ocean and Bering Sea over the twentieth century using the deuterium excess (d-excess) and methanesulfonic acid (MSA) records from the Mt. Hunter ice cores drilled in Denali National Park, Alaska. These parallel, 208 m-long ice cores were drilled to bedrock during the 2013 field season on the Mt. Hunter plateau (63° N, 151° W, 3,900 m above sea level) by a collaborative research team consisting of members from Dartmouth College and the Universities of Maine and New Hampshire. The cores were sampled on a continuous melter system at Dartmouth College and analyzed for the concentrations major ions (Dionex IC) and trace metals (Element2 ICPMS), and for stable water isotope ratios (Picarro). The depth-age scale has been accurately dated to 400 AD using annual layer counting of several chemical species and further validated using known historical volcanic eruptions and the Cesium-137 spike associated with nuclear weapons testing in 1963. We use HYSPLIT back trajectory modeling to identify likely source areas of moisture and aerosol MSA being transported to the core site. Satellite imagery allows for a direct comparison between chlorophyll a concentrations in these source areas and MSA concentrations in the core record. Preliminary analysis of chlorophyll a and MSA concentrations, both derived almost exclusively from marine biota, suggest that the Mt. Hunter ice cores reflect changes in North Pacific and Bering Sea marine primary productivity. Analysis of the water isotope and MSA data in conjunction with climate reanalysis products shows significant correlations (p<0.05) between d-excess and MSA in the ice record and sea surface temperatures in the Bering Sea and

  18. Response of Terrestrial Vegetation to Variations in Temperature and Aridity Since the Last Glacial Maximum in Lake Chalco, Mexico

    Science.gov (United States)

    Werne, J. P.; Halbur, J.; Rubesch, M.; Brown, E. T.; Ortega, B.; Caballero, M.; Correa-Metrio, A.; Lozano, S.

    2013-05-01

    The water balance of the Southwestern United States and most of Mexico is dependent on regional climate systems, including the Mexican (or North American) Monsoon. The Mexican Monsoon leads to significant summer rainfall across a broad swath of the continent, which constitutes the major source of annual precipitation over much of this region. The position of the ITCZ and the strength of the accompanying monsoon are affected by variability in insolation. Stronger northern hemisphere summer insolation shifts the ITCZ northward, bringing about a more intense monsoon. Here we discuss a new geochemical climate record from Lake Chalco, Mexico, which couples inorganic (X-ray fluorescence) and organic (biomarkers and stable isotopes) geochemical proxies to reconstruct temperature and aridity over the past 45,000 years, as well as the response of terrestrial vegetation to such climate changes. The Basin of Mexico is a high altitude closed lacustrine basin (20°N, 99°W; 2240 m.a.s.l.) in the Trans Mexican Volcanic Belt. The plain of Lake Chalco, located near Mexico City in the southern sub-basin, has an area of 120 km2 and a catchment of 1100 km2. Though the present-day lake has been reduced to a small marsh due to historic diversion of its waters, over longer timescales the lake has been a sensitive recorder of hydroclimatic variations. Low Ca concentrations indicate more arid periods during the late glacial (34 - 15 kybp) compared to the last interstadial or early Holocene. This observation is supported by the ratio of terrestrial to aquatic lipid biomarkers (long vs. short chain n-alkanes), which indicate greater relative inputs of aquatic biomarkers during wetter periods. The changes in aridity as shown in these geochemical proxies are compared with temperature as reflected in glycerol dialkyl glycerol tetraether (GDGT) based paleotemperature proxies to assess the extent to which insolation may have driven aridity variations, and with terrestrial and aquatic biomarker

  19. Climate Change: A New Metric to Measure Changes in the Frequency of Extreme Temperatures using Record Data

    Science.gov (United States)

    Munasinghe, L.; Jun, T.; Rind, D. H.

    2012-01-01

    Consensus on global warming is the result of multiple and varying lines of evidence, and one key ramification is the increase in frequency of extreme climate events including record high temperatures. Here we develop a metric- called "record equivalent draws" (RED)-based on record high (low) temperature observations, and show that changes in RED approximate changes in the likelihood of extreme high (low) temperatures. Since we also show that this metric is independent of the specifics of the underlying temperature distributions, RED estimates can be aggregated across different climates to provide a genuinely global assessment of climate change. Using data on monthly average temperatures across the global landmass we find that the frequency of extreme high temperatures increased 10-fold between the first three decades of the last century (1900-1929) and the most recent decade (1999-2008). A more disaggregated analysis shows that the increase in frequency of extreme high temperatures is greater in the tropics than in higher latitudes, a pattern that is not indicated by changes in mean temperature. Our RED estimates also suggest concurrent increases in the frequency of both extreme high and extreme low temperatures during 2002-2008, a period when we observe a plateauing of global mean temperature. Using daily extreme temperature observations, we find that the frequency of extreme high temperatures is greater in the daily minimum temperature time-series compared to the daily maximum temperature time-series. There is no such observable difference in the frequency of extreme low temperatures between the daily minimum and daily maximum.

  20. Variations of bubble cavitation and temperature elevation during lesion formation by high-intensity focused ultrasound.

    Science.gov (United States)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2013-08-01

    High-intensity focused ultrasound (HIFU) is emerging as an effective therapeutic modality in both thermal ablations for solid tumor/cancer and soft-tissue fragmentation. Mechanical and thermal effects, which play an important role in the HIFU treatment simultaneously, are dependent on the operating parameters and may vary with the progress of therapy. Mechanical erosion in the shape of a "squid," a "dumbbell" lesion with both mechanical and thermal lesions, or a "tadpole" lesion with mechanical erosion at the center and thermal necrosis on the boundary in the transparent gel phantom could be produced correspondingly with the pulse duration of 5-30 ms, which is much longer than histotripsy burst but shorter than the time for tissue boiling, and pulse repetition frequency (PRF) of 0.2-5 Hz. Meanwhile, variations of bubble cavitation (both inertial and stable cavitation) and temperature elevation in the focal region (i.e., z = -2.5, 0, and 2.5 mm) were measured by passive cavitation detection (PCD) and thermocouples during the therapeutic procedure, respectively. Stable cavitation increased with the pulse duration, PRF, and the number of pulses delivered. However, inertial cavitation was found to increase initially and then decrease with long pulse duration and high PRF. Temperature in the pre-focal region is always higher than those at the focal and post-focal position in all tests. Great variations of PCD signals and temperature elevation are due to the generation and persistence of large bubble, which is resistant to collapse and occurs with the increase of pulse duration and PRF. Similar lesion pattern and variations were also observed in ex vivo porcine kidneys. Hyperechoes in the B-mode ultrasound image were comparable to the shape and size of lesions in the dissected tissue. Thermal lesion volume increased with the increase of pulse duration and PRF, but mechanical erosion reached its maximum volume with the pulse duration of 20 ms and PRF of 1

  1. Reproducibility of Ba/Ca variations recorded by northeast Pacific bamboo corals

    Science.gov (United States)

    Serrato Marks, G.; LaVigne, M.; Hill, T. M.; Sauthoff, W.; Guilderson, T. P.; Roark, E. B.; Dunbar, R. B.; Horner, T. J.

    2017-09-01

    Trace elemental ratios preserved in the calcitic skeleton of bamboo corals have been shown to serve as archives of past ocean conditions. The concentration of dissolved barium (BaSW), a bioactive nutrientlike element, is linked to biogeochemical processes such as the cycling and export of nutrients. Recent work has calibrated bamboo coral Ba/Ca, a new BaSW proxy, using corals spanning the oxygen minimum zone beneath the California Current System. However, it was previously unclear whether Ba/Cacoral records were internally reproducible. Here we investigate the accuracy of using laser ablation inductively coupled plasma mass spectrometry for Ba/Cacoral analyses and test the internal reproducibility of Ba/Ca among replicate radial transects in the calcite of nine bamboo corals collected from the Gulf of Alaska (643-720 m) and the California margin (870-2054 m). Data from replicate Ba/Ca transects were aligned using visible growth bands to account for nonconcentric growth; smoothed data were reproducible within 4% for eight corals (n = 3 radii/coral). This intracoral reproducibility further validates using bamboo coral Ba/Ca for BaSW reconstructions. Sections of the Ba/Ca records that were potentially influenced by noncarbonate bound Ba phases occurred in regions where elevated Mg/Ca or Pb/Ca and coincided with anomalous regions on photomicrographs. After removing these regions of the records, increased Ba/Cacoral variability was evident in corals between 800 and 1500 m. These findings support additional proxy validation to understand BaSW variability on interannual timescales, which could lead to new insights into deep sea biogeochemistry over the past several centuries.

  2. Evidence of multidecadal climate variability and the Atlantic Multidecadal Oscillation from a Gulf of Mexico sea-surface temperature-proxy record

    Science.gov (United States)

    Poore, R.Z.; DeLong, K.L.; Richey, J.N.; Quinn, T.M.

    2009-01-01

    A comparison of a Mg/Ca-based sea-surface temperature (SST)-anomaly record from the northern Gulf of Mexico, a calculated index of variability in observed North Atlantic SST known as the Atlantic Multidecadal Oscillation (AMO), and a tree-ring reconstruction of the AMO contain similar patterns of variation over the last 110 years. Thus, the multidecadal variability observed in the instrumental record is present in the tree-ring and Mg/Ca proxy data. Frequency analysis of the Gulf of Mexico SST record and the tree-ring AMO reconstruction from 1550 to 1990 found similar multidecadal-scale periodicities (???30-60 years). This multidecadal periodicity is about half the observed (60-80 years) variability identified in the AMO for the 20th century. The historical records of hurricane landfalls reveal increased landfalls in the Gulf Coast region during time intervals when the AMO index is positive (warmer SST), and decreased landfalls when the AMO index is negative (cooler SST). Thus, we conclude that alternating intervals of high and low hurricane landfall occurrences may continue on multidecadal timescales along the northern Gulf Coast. However, given the short length of the instrumental record, the actual frequency and stability of the AMO are uncertain, and additional AMO proxy records are needed to establish the character of multidecadal-scale SST variability in the North Atlantic. ?? 2009 US Government.

  3. Lithium isotopes in speleothems: Temperature-controlled variation in silicate weathering during glacial cycles

    Science.gov (United States)

    Pogge von Strandmann, Philip A. E.; Vaks, Anton; Bar-Matthews, Miryam; Ayalon, Avner; Jacob, Ezekiel; Henderson, Gideon M.

    2017-07-01

    Terrestrial chemical weathering of silicate minerals is a fundamental component of the global cycle of carbon and other elements. Past changes in temperature, rainfall, ice cover, sea-level and physical erosion are thought to affect weathering but the relative impact of these controls through time remains poorly constrained. This problem could be addressed if the nature of past weathering could be constrained at individual sites. In this study, we investigate the use of speleothems as local recorders of the silicate weathering proxy, Li isotopes. We analysed δ7 Li and [Li] in speleothems that formed during the past 200 ka in two well-studied Israeli caves (Soreq and Tzavoa), as well as in the overlying soils and rocks. Leaching and mass balance of these soils and rocks show that Li is dominantly sourced from weathering of the overlying aeolian silicate soils. Speleothem δ7 Li values are ubiquitously higher during glacials (∼23‰) than during interglacials (∼10‰), implying more congruent silicate weathering during interglacials (where ;congruent; means a high ratio of primary mineral dissolution to secondary mineral formation). These records provide information on the processes controlling weathering in Israel. Consideration of possible processes causing this change of weathering congruency indicates a primary role for temperature, with higher temperatures causing more congruent weathering (lower δ7Lispeleo). The strong relationship observed between speleothem δ7 Li and climate at these locations suggests that Li isotopes may be a powerful tool with which to understand the local controls on weathering at other sites, and could be used to assess the distribution of weathering changes accompanying climate change, such as that of Pleistocene glacial cycles.

  4. Spatial and temporal variation of correlation between the Arctic total ozone and atmospheric temperature

    Science.gov (United States)

    Huang, Fuxiang; Ren, suling; Han, Shuangshuang; Zheng, xiangdong; Deng, xuejiao

    2017-04-01

    Daily total ozone and atmospheric temperature profile data in 2015 from the AIRS are used to investigate the spatial and temporal variation of the correlation between the Arctic atmospheric ozone and temperature. In the study, 11 lays atmospheric temperature profiles from the troposphere to the stratosphere are investigated. These layer heights are 20, 50, 70, 100, 200, 250, 300, 400, 500, 600 and 700 hPa respectively. The results show that a significant seasonal split exists in the correlation between the Arctic ozone and atmospheric temperature. Figure 1 shows the spatial and temporal variation of the coefficient between the atmospheric ozone and temperature at 50hPa. It can be seen from the figure that an obvious spatiotemporal difference exists in the correlation between the Arctic total ozone and atmospheric temperature in the lower stratosphere. First, the seasonal difference is very remarkable, which is shown as a significant positive correlation in most regions during winter and summer, while no correlation in the majority of regions occurs during spring and autumn, with a weak positive or negative correlation in a small number regions. Second, the spatial differences are also very obvious. The summer maximum correlation coefficient occurs in the Barents Sea and other locations at 0.8 and above, while the winter maximum occurs in the Baffin Bay area at 0.6 to 0.8. However, in a small number of regions, such as the land to the west of the Bering Strait in winter and the Arctic Ocean core area in summer, the correlation coefficients were unable to pass the significance test to show no correlation. At the same time, in spring and autumn, a positive correlation only occurs over a few low-latitude land areas, while over other Arctic areas, weak negative correlation exists. The differences in horizontal position are clearly related to the land-sea distribution, underlying surface characteristics, glacial melting, and other factors. In the troposphere, the ozone

  5. Methods for quantifying the influences of pressure and temperature variation on metal hydride reaction rates measured under isochoric conditions.

    Science.gov (United States)

    Voskuilen, Tyler G; Pourpoint, Timothée L

    2013-11-01

    Analysis techniques for determining gas-solid reaction rates from gas sorption measurements obtained under non-constant pressure and temperature conditions often neglect temporal variations in these quantities. Depending on the materials in question, this can lead to significant variations in the measured reaction rates. In this work, we present two new analysis techniques for comparison between various kinetic models and isochoric gas measurement data obtained under varying temperature and pressure conditions in a high pressure Sievert system. We introduce the integral pressure dependence method and the temperature dependence factor as means of correcting for experimental variations, improving model-measurement fidelity, and quantifying the effect that such variations can have on measured reaction rates. We use measurements of hydrogen absorption in LaNi5 and TiCrMn to demonstrate the effect of each of these methods and show that their use can provide quantitative improvements in interpretation of kinetics measurements.

  6. Speleothem records decadal to multidecadal hydroclimate variations in southwestern Morocco during the last millennium

    Science.gov (United States)

    Ait Brahim, Yassine; Cheng, Hai; Sifeddine, Abdelfettah; Wassenburg, Jasper A.; Cruz, Francisco W.; Khodri, Myriam; Sha, Lijuan; Pérez-Zanón, Núria; Beraaouz, El Hassane; Apaéstegui, James; Guyot, Jean-Loup; Jochum, Klaus Peter; Bouchaou, Lhoussaine

    2017-10-01

    This study presents the first well-dated high resolution stable isotope (δ18 O and δ13 C) and trace element (Mg and Sr) speleothem records from southwestern Morocco covering the last 1000 yrs. Our records reveal substantial decadal to multidecadal swings between dry and humid periods, consistent with regional paleorecords with prevailing dry conditions during the Medieval Climate Anomaly (MCA), wetter conditions during the second part of the Little Ice Age (LIA), and a trend towards dry conditions during the current warm period. These coherent regional climate signals suggest common climate controls. Statistical analyses indicate that the climate of southwestern Morocco remained under the combined influence of both the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) over the last millennium. Interestingly, the generally warmer MCA and colder LIA at longer multidecadal timescales probably influenced the regional climate in North Africa through the influence on Sahara Low which weakened and strengthened the mean moisture inflow from the Atlantic Ocean during the MCA and LIA respectively.

  7. Oxygen isotope variations at the margin of a CAI records circulation within the solar nebula.

    Science.gov (United States)

    Simon, Justin I; Hutcheon, Ian D; Simon, Steven B; Matzel, Jennifer E P; Ramon, Erick C; Weber, Peter K; Grossman, Lawrence; DePaolo, Donald J

    2011-03-04

    Micrometer-scale analyses of a calcium-, aluminum-rich inclusion (CAI) and the characteristic mineral bands mantling the CAI reveal that the outer parts of this primitive object have a large range of oxygen isotope compositions. The variations are systematic; the relative abundance of (16)O first decreases toward the CAI margin, approaching a planetary-like isotopic composition, then shifts to extremely (16)O-rich compositions through the surrounding rim. The variability implies that CAIs probably formed from several oxygen reservoirs. The observations support early and short-lived fluctuations of the environment in which CAIs formed, either because of transport of the CAIs themselves to distinct regions of the solar nebula or because of varying gas composition near the proto-Sun.

  8. Spatial and Temporal Variations in Titan's Surface Temperatures from Cassini CIRS Observations

    Science.gov (United States)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; deKok, R.; Teanby, N. A.; Irwin, P. G. J.; Flasar, F. M.

    2012-01-01

    We report a wide-ranging study of Titan's surface temperatures by analysis of the Moon's outgoing radiance through a spectral window in the thermal infrared at 19 mm (530/cm) characterized by lower atmospheric opacity. We begin by modeling Cassini Composite Infrared Spectrometer (CIRS) far infrared spectra collected in the period 2004-2010, using a radiative transfer forward model combined with a non-linear optimal estimation inversion method. At low-latitudes, we agree with the HASI near-surface temperature of about 94 K at 101S (Fulchignoni et al., 2005). We find a systematic decrease from the equator toward the poles, hemispherically asymmetric, of approx. 1 K at 60 deg. south and approx. 3 K at 60 deg. north, in general agreement with a previous analysis of CIRS data and with Voyager results from the previous northern winter. Subdividing the available database, corresponding to about one Titan season, into 3 consecutive periods, small seasonal changes of up to 2 K at 60 deg N became noticeable in the results. In addition, clear evidence of diurnal variations of the surface temperatures near the equator are observed for the first time: we find a trend of slowly increasing temperature from the morning to the early afternoon and a faster decrease during the night. The diurnal change is approx. 1.5 K, in agreement with model predictions for a surface with a thermal inertia between 300 and 600 J/ sq. m s (exp -1/2) / K. These results provide important constraints on coupled surface-atmosphere models of Titan's meteorology and atmospheric dynamic.

  9. Evidence of a warm early instrumental period found in temperature related water isotope records from high elevation Alpine ice cores

    Science.gov (United States)

    Bohleber, Pascal; Schöner, Wolfgang; Wagenbach, Dietmar

    2015-04-01

    The variability of water isotopes (delta-O18 or delta-D) preserved in Alpine glacier ice may provide mid-latitude temperature proxy records supplementing respective information from other archives. In order to archive long term records (i.e. exceeding 100 years) the limited glacier depth at suitable Alpine drill sites requires a relatively low net accumulation rate. In this respect, the cold glacier saddle Colle Gnifetti (CG) is the unique drilling site in the European Alps offering ice core records substantially exceeding the instrumental period. However, the unique low net accumulation at CG is characterised by strong spatio-temporal variability causing depositional noise that strongly challenges the interpretation of the ice core isotope records in terms of net temperature change. Here we present our findings from comparing stable water isotope records of the CG multi core array to a site-specific temperature time series. The latter is synthesized from high elevation stations of the instrumental HISTALP network considering among others the temperature shift from the accumulation bias towards growing seasons. Within the last century dedicated time series analysis reveals a common signal in the (supra-) decadal components of the instrumental temperature and isotope records. Extending the comparison over the entire 250 years instrumental period, systematic discrepancies are found within the early instrumental period (EIP). The delta-O18 record shows an overall decreasing trend from 1760 to 1890 AD, which is not reflected in the temperature record. However, using high Alpine summer temperature lacking the latest EIP adjustment, the long-term trends between isotope and instrumental data are in better agreement. The overall mean of the isotope based temperature in the EIP indicates substantially warmer levels than the EIP-corrected instrumental temperature. It differs, however, not significantly with respect to the non-EIP-corrected temperature mean. Although the main

  10. Interannual variation patterns of total ozone and lower stratospheric temperature in observations and model simulations

    Directory of Open Access Journals (Sweden)

    W. Steinbrecht

    2006-01-01

    Full Text Available We report results from a multiple linear regression analysis of long-term total ozone observations (1979 to 2000, by TOMS/SBUV, of temperature reanalyses (1958 to 2000, NCEP, and of two chemistry-climate model simulations (1960 to 1999, by ECHAM4.L39(DLR/CHEM (=E39/C, and MAECHAM4-CHEM. The model runs are transient experiments, where observed sea surface temperatures, increasing source gas concentrations (CO2, CFCs, CH4, N2O, NOx, 11-year solar cycle, volcanic aerosols and the quasi-biennial oscillation (QBO are all accounted for. MAECHAM4-CHEM covers the atmosphere from the surface up to 0.01 hPa (≈80 km. For a proper representation of middle atmosphere (MA dynamics, it includes a parametrization for momentum deposition by dissipating gravity wave spectra. E39/C, on the other hand, has its top layer centered at 10 hPa (≈30 km. It is targeted on processes near the tropopause, and has more levels in this region. Despite some problems, both models generally reproduce the observed amplitudes and much of the observed low-latitude patterns of the various modes of interannual variability in total ozone and lower stratospheric temperature. In most aspects MAECHAM4-CHEM performs slightly better than E39/C. MAECHAM4-CHEM overestimates the long-term decline of total ozone, whereas underestimates the decline over Antarctica and at northern mid-latitudes. The true long-term decline in winter and spring above the Arctic may be underestimated by a lack of TOMS/SBUV observations in winter, particularly in the cold 1990s. Main contributions to the observed interannual variations of total ozone and lower stratospheric temperature at 50 hPa come from a linear trend (up to -10 DU/decade at high northern latitudes, up to -40 DU/decade at high southern latitudes, and around -0.7 K/decade over much of the globe, from the intensity of the polar vortices (more than 40 DU, or 8 K peak to peak, the QBO (up to 20 DU, or 2 K peak to peak, and from

  11. Record-high specific conductance and water temperature in San Francisco Bay during water year 2015

    Science.gov (United States)

    Work, Paul; Downing-Kunz, Maureen; Livsey, Daniel

    2017-02-22

    The San Francisco estuary is commonly defined to include San Francisco Bay (bay) and the adjacent Sacramento–San Joaquin River Delta (delta). The U.S. Geological Survey (USGS) has operated a high-frequency (15-minute sampling interval) water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2014). This network includes 19 stations at which sustained measurements have been made in the bay; currently, 8 stations are in operation (fig. 1). All eight stations are equipped with specific conductance (which can be related to salinity) and water-temperature sensors. Water quality in the bay constantly changes as ocean tides force seawater in and out of the bay, and river inflows—the most significant coming from the delta—vary on time scales ranging from those associated with storms to multiyear droughts. This monitoring network was designed to observe and characterize some of these changes in the bay across space and over time. The data demonstrate a high degree of variability in both specific conductance and temperature at time scales from tidal to annual and also reveal longer-term changes that are likely to influence overall environmental health in the bay.In water year (WY) 2015 (October 1, 2014, through September 30, 2015), as in the preceding water year (Downing-Kunz and others, 2015), the high-frequency measurements revealed record-high values of specific conductance and water temperature at several stations during a period of reduced freshwater inflow from the delta and other tributaries because of persistent, severe drought conditions in California. This report briefly summarizes observations for WY 2015 and compares them to previous years that had different levels of freshwater inflow.

  12. Small sensitivity to temperature variations of Si-photonic Mach-Zehnder interferometer using Si and SiN waveguides

    Directory of Open Access Journals (Sweden)

    Tatsurou eHiraki

    2015-03-01

    Full Text Available We demonstrated a small sensitivity to temperature variations of delay-line Mach-Zehnder interferometer (DL MZI on a Si photonics platform. The key technique is to balance a thermo-optic effect in the two arms by using waveguide made of different materials. With silicon and silicon nitride waveguides, the fabricated DL MZI with a free-spectrum range of ~40 GHz showed a wavelength shift of -2.8 pm/K with temperature variations, which is 24 times smaller than that of the conventional Si-waveguide DL MZI. We also demonstrated the decoding of the 40-Gbit/s differential phase-shift keying signals to on-off keying signals with various temperatures. The tolerable temperature variation for the acceptable power penalty was significantly improved due to the small wavelength shifts.

  13. Variations in North Pacific sea surface temperature caused by Arctic stratospheric ozone anomalies

    Science.gov (United States)

    Xie, Fei; Li, Jianping; Zhang, Jiankai; Tian, Wenshou; Hu, Yongyun; Zhao, Sen; Sun, Cheng; Ding, Ruiqing; Feng, Juan; Yang, Yun

    2017-11-01

    Recently, observations and simulations have shown that Arctic stratospheric ozone (ASO) variations affect the middle–high latitude tropospheric climate in the Northern Hemisphere. In particular, a connection from the ASO to El Niño–Southern Oscillation (ENSO) has been reported. However, no detailed study has been made of a key process in the connection, the influence of ASO on the North Pacific sea surface temperature (SST) and its underlying mechanism. Using observations, reanalysis and simulations, it is found that the ASO changes in March have the strongest connection with North Pacific SST variations in April. This implies a leading effect of ASO on North Pacific SST. The stratospheric circulation anomalies caused by March ASO changes can rapidly extend to the lower troposphere in the region 60°–90°N, 180°–120°W. Nevertheless, a theoretical analysis indicates that circulation anomalies from the region 60°–90°N, 180°–120°W in the lower troposphere would take about a month to propagate horizontally to the North Pacific middle latitudes (30°–60°N, 180°–120°W).

  14. Detonation shock dynamics calibration for pBX 9502 with temperature, density, and material lot variations

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Larry G [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

    2010-01-01

    We present a methodology for scaling the detonation shock dynamics D{sub n}[{kappa}] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T{sub 0}, nominal density {rho}{sub 0}, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, {delta}. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on {delta}. This results in a D{sub n}[{kappa}] function that depends on T{sub 0}, {rho}{sub 0}, and {delta}. After examining the separate effects of each parameter on D{sub n}[{kappa}], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

  15. Interannual Variation of the Surface Temperature of Tropical Forests from Satellite Observations

    Directory of Open Access Journals (Sweden)

    Huilin Gao

    2016-01-01

    Full Text Available Land surface temperatures (LSTs within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I and the Special Sensor Microwave Imager Sounder (SSMIS, providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability of cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP reanalysis data.

  16. Aquarius Brightness Temperature Variations at Dome C and Snow Metamorphism at the Surface. [29

    Science.gov (United States)

    Brucker, Ludovic; Dinnat, Emmanuel Phillippe; Picard, Ghislain; Champollion, Nicolas

    2014-01-01

    The Antarctic Plateau is a promising site to monitor microwave radiometers' drift, and to inter-calibrate microwave radiometers, especially 1.4 GHz (L-band) radiometers on board the Soil Moisture and Ocean Salinity (SMOS), and AquariusSAC-D missions. The Plateau is a thick ice cover, thermally stable in depth, with large dimensions, and relatively low heterogeneities. In addition, its high latitude location in the Southern Hemisphere enables frequent observations by polar-orbiting satellites, and no contaminations by radio frequency interference. At Dome C (75S, 123E), on the Antarctic Plateau, the substantial amount of in-situ snow measurements available allows us to interpret variations in space-borne microwave brightness temperature (TB) (e.g. Macelloni et al., 2007, 2013, Brucker et al., 2011, Champollion et al., 2013). However, to analyze the observations from the Aquarius radiometers, whose sensitivity is 0.15 K, the stability of the snow layers near the surface that are most susceptible to rapidly change needs to be precisely assessed. This study focuses on the spatial and temporal variations of the Aquarius TB over the Antarctic Plateau, and at Dome C in particular, to highlight the impact of snow surface metamorphism on the TB observations at L-band.

  17. Late Glacial to Holocene abrupt temperature changes recorded by Crenarchaeota in Lake Lucerne (Vierwaldstättersee, Switzerland)

    Science.gov (United States)

    Blaga, Cornelia I.; Reichart, Gert-Jan; Lotter, André F.; Anselmetti, Flavio; Sinninghe Damsté, Jaap S.

    2010-05-01

    In this study we applied the TEX86 (TetraEther Index of 86 carbon atoms) temperature proxy to a sediment core from Lake Lucerne (Vierwaldstättersee) to reconstruct, in almost decadal resolution, temperature changes during the Younger Dryas and the Early Holocene (ca. 14600 to 10600 cal. BP). The TEX86 proxy suggests a sequence of shifts during the late glacial period that strongly resemble the shifts in δ18O values from the Greenland ice core record. The TEX86-reconstructed lake temperature record indicates a step-wise pattern of climate changes across the studied interval with a shift from colder to warmer temperatures at the onset of the late-glacial interstadial, followed by an abrupt cooling at the onset of Younger Dryas and a rapid warming from 5.5 to 9°C at the Younger Dryas/Holocene transition in less than 200 years. The temperature change associated with the Interstadial-Younger Dryas alternation is ca. 4 °C and is in line with previous temperature reconstructions based on different proxies. The rapid changes in temperature associated with the last deglaciation are reflected in the highest possible detail in the TEX86 record. It is thus clear that our proxy, based on the isoprenoidal GDGTs (Glycerol Dialkyl Glycerol Tetraethers), is capable to reflect high resolution records of rapid (decadal to century scale oscillations) environmental fluctuations comparable with those obtained from ice cores.

  18. Study of spectro-temporal variation in paleo-climatic marine proxy records using wavelet transformations

    Science.gov (United States)

    Pandey, Chhavi P.

    2017-10-01

    Wavelet analysis is a powerful mathematical and computational tool to study periodic phenomena in time series particu-larly in the presence of potential frequency changes in time. Continuous wavelet transformation (CWT) provides localised spectral information of the analysed dataset and in particular useful to study multiscale, nonstationary processes occurring over finite spatial and temporal domains. In the present work, oxygen-isotope ratio from the plantonic foraminifera species (viz. Globigerina bul-loides and Globigerinoides ruber) acquired from the broad central plateau of the Maldives ridge situated in south-eastern Arabian sea have been used as climate proxy. CWT of the time series generated using both the biofacies indicate spectro-temporal varia-tion of the natural climatic cycles. The dominant period resembles to the period of Milankovitch glacial-interglacial cycle. Apart from that, various other cycles are present in the time series. The results are in good agreement with the astronomical theory of paleoclimates and can provide better visualisation of Indian summer monsoon in the context of climate change.

  19. Thermodynamics of Micro- and Nano-Systems Driven by Periodic Temperature Variations

    Directory of Open Access Journals (Sweden)

    Kay Brandner

    2015-08-01

    Full Text Available We introduce a general framework for analyzing the thermodynamics of small systems that are driven by both a periodic temperature variation and some external parameter modulating their energy. This setup covers, in particular, periodic micro- and nano-heat engines. In a first step, we show how to express total entropy production by properly identified time-independent affinities and currents without making a linear response assumption. In linear response, kinetic coefficients akin to Onsager coefficients can be identified. Specializing to a Fokker-Planck-type dynamics, we show that these coefficients can be expressed as a sum of an adiabatic contribution and one reminiscent of a Green-Kubo expression that contains deviations from adiabaticity. Furthermore, we show that the generalized kinetic coefficients fulfill an Onsager-Casimir-type symmetry tracing back to microscopic reversibility. This symmetry allows for nonidentical off-diagonal coefficients if the driving protocols are not symmetric under time reversal. We then derive a novel constraint on the kinetic coefficients that is sharper than the second law and provides an efficiency-dependent bound on power. As one consequence, we can prove that the power vanishes at least linearly when approaching Carnot efficiency. We illustrate our general framework by explicitly working out the paradigmatic case of a Brownian heat engine realized by a colloidal particle in a time-dependent harmonic trap subject to a periodic temperature profile. This case study reveals inter alia that our new general bound on power is asymptotically tight.

  20. Empirical Mode Decomposition on the sphere: application to the spatial scales of surface temperature variations

    Directory of Open Access Journals (Sweden)

    N. Fauchereau

    2008-06-01

    Full Text Available Empirical Mode Decomposition (EMD is applied here in two dimensions over the sphere to demonstrate its potential as a data-adaptive method of separating the different scales of spatial variability in a geophysical (climatological/meteorological field. After a brief description of the basics of the EMD in 1 then 2 dimensions, the principles of its application on the sphere are explained, in particular via the use of a zonal equal area partitioning. EMD is first applied to an artificial dataset, demonstrating its capability in extracting the different (known scales embedded in the field. The decomposition is then applied to a global mean surface temperature dataset, and we show qualitatively that it extracts successively larger scales of temperature variations related, for example, to topographic and large-scale, solar radiation forcing. We propose that EMD can be used as a global data-adaptive filter, which will be useful in analysing geophysical phenomena that arise as the result of forcings at multiple spatial scales.

  1. Tensile Properties and Deflection Temperature of Polypropylene/Sumberejo Kenaf Fiber Composites with Fiber Content Variation

    Science.gov (United States)

    Ollivia, S. L.; Juwono, A. L.; Roseno, Seto

    2017-05-01

    The use of synthetic fibers as reinforcement in composites has disadvantage which are unsustainable and an adverse impact on the environment. An alternative reinforcement for composites is natural fiber. Polypropylene and Sumberejo kenaf fibers were used respectively as the matrix and reinforcement. The aim of this research was to obtain the optimum tensile properties and deflection temperature with the variation of kenaf fiber fractions. Polypropylene/kenaf fiber composites were fabricated by hot press method. The kenaf fiber was soaked in NaOH solution before being used as the reinforcement and polypropylene was extruded before being used as the matrix. The weight fractions were varied to produce composites and pristine polypropylene samples were also prepared for comparison. The optimum tensile strength, modulus and deflection temperature were found in the composites with the 40 wt% kenaf fiber fraction with an increase up to 80% and 170% compared to the pristine polypropylene with the values of (60.3 ± 4,3) MPa and (159.1 ± 1,8) °C respectively. The Scanning Electron Microscope observation results in the fracture surface of the composites with the 40 wt% fiber fraction showed a relatively good bonding interface between fibers and the matrix and the failure modes were fiber breakage and matrix failures.

  2. Modeling of adsorption isotherms on the addition of an inhibitor Myrmecodia Pendans extract with temperature variation

    Science.gov (United States)

    Pradityana, Atria; Sulistijono, Husodo, Nur; Winarto, Gatot Dwi; Bangun, Sri; Sampurno, Bambang

    2017-05-01

    In research carried out measurements of weight loss with API 5L grade B material in a solution of HCl 1 M. Extract Myrmecodia Pendans is used as a corrosion inhibitor. Immersion time was 2 hours, while the temperature variations used are 30, 40 and 50°C. Extracts of the ants 100-500 mg / L (multiples of 100 mg / L). In this study will also be analyzed with some models of adsorption mechanisms, including the Langmuir, Freundlich, and Temkin. This study aimed to determine the appropriate method of adsorption isotherms on each system. Adsorption equations of the model will be obtained values of free energy of a system. With the known value of free energy, it can be seen whether the adsorption occurs in physics or chemistry. This related to the surface protective layer formed on the surface absorption extract Myrmecodia Pendans. The results showed that the adsorption followed the Langmuir adsorption method at 30 and 40°C, while the temperature of 50°C followed Freundlich adsorption methods.

  3. The Impact of Morphological Features on Summer Temperature Variations on the Example of Two Residential Neighborhoods in Ljubljana, Slovenia

    Directory of Open Access Journals (Sweden)

    Alenka Fikfak

    2017-01-01

    Full Text Available The study conducted in this paper is focused on a predominantly residential area of the City of Ljubljana—Koseze, which is characterized by generally favorable (bioclimatic conditions. Nonetheless, thermal satellite images showed that residential neighborhoods within the Koseze district display unexpected variations in summer temperatures. This observation called into question the benefits of existing bioclimatic features and indicated the need to investigate and compare two neighborhoods with similar urban parameters, with the aim to identify morphological differential characteristics impacting urban heat island (UHI intensity. By applying the study methodology based on a literature review, surveys of key precedents, detailed mapping in two Koseze locations, in situ measurements, observations and recordings, thermal imagery, and the analyses of statistical data, as well as by defining the four main categories of morphological urban parameters—structure, cover, fabric and metabolism, it was concluded that both neighborhoods have common morphological elements mitigating the UHI effect. Additionally, it was found that the neighborhood with higher UHI intensity has several less favorable features, such as busier roads, larger surface of parking corridors, and the existence of underground parking space. The traffic as an element of urban morphology hence represents the main cause of differences among UHI levels in the two Koseze neighborhoods.

  4. Timing of strain localization in high-pressure low-temperature shear zones: The argon isotopic record

    Science.gov (United States)

    Laurent, Valentin; Scaillet, Stéphane; Jolivet, Laurent; Augier, Romain

    2017-04-01

    The complex interplay between rheology, temperature and deformation profoundly influences how crustal-scale shear zones form and then evolve across a deforming lithosphere. Understanding early exhumation processes in subduction zones requires quantitative age constraints on the timing of strain localization within high-pressure shear zones. Using both the in situ laser ablation and conventional step-heating 40Ar/39Ar dating (on phengite single grains and populations) methods, this study aims at quantifying the duration of ductile deformation and the timing of strain localization within HP-LT shear zones of the Cycladic Blueschist Unit (CBU, Greece). The rate of this progressive strain localization is unknown, and in general, poorly known in similar geological contexts. Critical to retrieve realistic estimates of rates of strain localization during exhumation, dense 40Ar/39Ar age transects were sampled along shear zones recently identified on Syros and Sifnos islands. There, field observations suggest that deformation progressively localized downward in the CBU during exhumation. In parallel, these shear zones are characterized by different degrees of retrogression from blueschist-facies to greenschist-facies P-T conditions overprinting eclogite-facies record throughout the CBU. Results show straightforward correlations between the degree of retrogression, the finite strain intensity and 40Ar/39Ar ages; the most ductilely deformed and retrograded rocks yielded the youngest 40Ar/39Ar ages. The possible effects of strain localization during exhumation on the record of the argon isotopic system in HP-LT shear zones are addressed. Our results show that strain has localized in shear zones over a 30 Ma long period and that individual shear zones evolve during 7-15 Ma. We also discuss these results at small-scale to see whether deformation and fluid circulations, channelled within shear bands, can homogenize chemical compositions and reset the 40Ar/39Ar isotopic record

  5. Multiple Nebular Gas Reservoirs Recorded by Oxygen Isotope Variation in a Spinel-rich CAI in CO3 MIL 090019

    Science.gov (United States)

    Simon, J. I.; Simon, S. B.; Nguyen, A. N.; Ross, D. K.; Messenger, S.

    2017-01-01

    We conducted NanoSIMS O-isotopic imaging of a primitive spinel-rich CAI spherule (27-2) from the MIL 090019 CO3 chondrite. Inclusions such as 27-2 are proposed to record inner nebula processes during an epoch of rapid solar nebula evolution. Mineralogical and textural analyses suggest that this CAI formed by high temperature reactions, partial melting, and condensation. This CAI exhibits radial O-isotopic heterogeneity among multiple occurrences of the same mineral, reflecting interactions with distinct nebular O-isotopic reservoirs.

  6. Denali Ice Core Record of North Pacific Sea Surface Temperatures and the Pacific Decadal Oscillation

    Science.gov (United States)

    Polashenski, D.; Osterberg, E. C.; Winski, D.; Ferris, D. G.; Kreutz, K. J.; Wake, C. P.; Introne, D.

    2015-12-01

    Ice cores collected from high elevation alpine glaciers in the Alaska Range provide a unique opportunity to investigate changes in the regional climate of southern Alaska and the north Pacific over the past millennium. In this study, we seek to investigate changes in sea surface temperature (SST) in the north-central Pacific Ocean using the deuterium excess (d-excess) record from the Mt. Hunter ice cores collected in Denali National Park, Alaska. A collaborative research team from Dartmouth College and the Universities of Maine and New Hampshire collected two parallel ice cores to bedrock (208 m long) in May-June 2013 from the Mt. Hunter summit plateau (63º N, 151º W, 4,000 m above sea level). The cores were melted on a continuous melter system in the Dartmouth ice core lab and then analyzed for concentrations of major ions and trace elements, as well as stable water isotope ratios. The depth-age scale of the cores was determined using annual layer counting of δ18O and the concentrations of Mg, NH4, and Methanesulfonic acid (MSA) obtained by ion chromatography. The depth-age scale was validated using large, well-dated volcanic eruptions and the spike in 137Cs concentrations associated with nuclear weapons testing in 1963. Preliminary analyses indicate that the full record spans the past millennium. Analysis of the isotope data set extending back to 1938 using reanalysis data shows a positive correlation (p<0.05) between d-excess at the core site and the north-central Pacific SST. The north-central Pacific region of positive SST-d-excess correlation occurs at one node of the Pacific Decadal Oscillation (PDO), and thus the Denali cores are sensitive to PDO variability with low (high) d-excess associated with positive (negative) PDO index values. We also note a significant (p<0.05) declining trend in d-excess from 1938-2012, which we hypothesize to represent a rising proportion of Arctic moisture sources influencing Denali as Arctic temperatures and evaporation

  7. Pacific Reef Assessment and Monitoring Program: Subsurface Temperature Recorders (STRs) at selected coral reef locations across the Pacific Ocean from 2001 to 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  8. Late Quaternary water temperature variations of the Northwest Pacific based on the lipid paleothermometers TEXH86, UK´37 and LDI

    Science.gov (United States)

    Jonas, A.-S.; Schwark, L.; Bauersachs, T.

    2017-07-01

    The Kuroshio Current (KC) and Oyashio Current (OC) are the two major western boundary currents of the Pacific Ocean and their interplay exerts a major control on the climate evolution of the northwestern Pacific region as well as East Asia. Although millennial scale variations in the strength and flow pattern of the KC are well documented, only little is known on the long-term evolution of this ocean current and its role in affecting regional and global climate over geological time scales. Here, we present surface and thermocline temperature records covering the last two glacial-interglacial cycles of IODP (Integrated Ocean Drilling Program) Site C0011, SE of Japan, using the lipid paleothermometers TEXH86 (tetraether index of tetraethers consisting of 86 carbon atoms), UK´37 (unsaturated ketone index) and LDI (long-chain diol index). Lower average water temperatures (20.1-20.7 °C in TEXH86, 21.6-22.0 °C in UK´37, and 20.7-21.9 °C in LDI) during marine isotope stages (MIS) 2 and 6 are considered to indicate a reduction in warm water mass export from the Western Pacific Warm Pool (WPWP) to northern mid-latitudes via the KC due to decreased subtropical gyre circulation in the North Pacific. A synchronous southward displacement of the KC/OC interfrontal zone resulted in an overall stronger influence of colder and more polar waters at Site C0011. MIS 1, 3 and 5 are characterized by generally higher water temperatures (21.7-22.1 °C in TEXH86, 23.2-24.3 °C in UK´37, and 23.1-24.3 °C in LDI), likely reflecting an increased northward transport of subtropical waters to the study site. Higher Holocene than Eemian water temperatures are attributed to a stronger KC and the formation of its short meander south of Japan, whereas a less strong KC during the Eemian likely favored the formation of the large meander path. Better correlations between the different lipid paleothermometers during cold MIS are considered to indicate more similar production seasons and habitat

  9. Meteosat Land Surface Temperature Climate Data Record: Achievable Accuracy and Potential Uncertainties

    Directory of Open Access Journals (Sweden)

    Anke Duguay-Tetzlaff

    2015-10-01

    Full Text Available The European Organization for the Exploitation of Meteorological Satellites’ (EUMETSAT Meteosat satellites provide the unique opportunity to compile a 30+ year land surface temperature (LST climate data record. Since the Meteosat instrument on-board Meteosat 2–7 is equipped with a single thermal channel, single-channel LST retrieval algorithms are used to ensure consistency across Meteosat satellites. The present study compares the performance of two single-channel LST retrieval algorithms: (1 A physical radiative transfer-based mono-window (PMW; and (2 a statistical mono-window model (SMW. The performance of the single-channel algorithms is assessed using a database of synthetic radiances for a wide range of atmospheric profiles and surface variables. The two single-channel algorithms are evaluated against the commonly-used generalized split-window (GSW model. The three algorithms are verified against more than 60,000 LST ground observations with dry to very moist atmospheres (total column water vapor (TCWV 1–56 mm. Except for very moist atmospheres (TCWV > 45 mm, results show that Meteosat single-channel retrievals match those of the GSW algorithm by 0.1–0.5 K. This study also outlines that it is possible to put realistic uncertainties on Meteosat single-channel LSTs, except for very moist atmospheres: simulated theoretical uncertainties are within 0.3–1.0 K of the in situ root mean square differences for TCWV < 45 mm.

  10. Direct effects of temperature on forest nitrogen cycling revealed through analysis of long-term watershed records

    Science.gov (United States)

    E.N. Jack Brookshire; Stefan Gerber; Jackson R. Webster; James M. Vose; Wayne T. Swank

    2010-01-01

    The microbial conversion of organic nitrogen (N) to plant available forms is a critical determinant of plant growth and carbon sequestration in forests worldwide. In temperate zones, microbial activity is coupled to variations in temperature, yet at the ecosystem level, microbial N mineralization seems to play a minor role in determining patterns of N loss. Rather, N...

  11. Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

    Science.gov (United States)

    Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

    2018-02-01

    Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300-500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and

  12. Effect of diurnal and seasonal temperature variation on Cussac cave ventilation using co2 assessment

    Science.gov (United States)

    Peyraube, Nicolas; Lastennet, Roland; Villanueva, Jessica Denila; Houillon, Nicolas; Malaurent, Philippe; Denis, Alain

    2017-08-01

    Cussac cave was investigated to assess the cave air temperature variations and to understand its ventilation regime. This cave is located in an active karst system in the south west part of France. It has a single entrance and is considered as a cold air trap. In this study, air mass exchanges were probed. Measurements of temperature and Pco2 with a 30-min frequency were made in several locations close to the cave entrance. Speed of the air flow was also measured at the door of cave entrance. Results show that cave air Pco2 varies from 0.18 to 3.33 %. This cave appears to be a CO2 source with a net mass of 2319 tons blown in 2009. Carbon-stable isotope of CO2 (13Cco2) ranges from -20.6 ‰ in cold season to -23.8 ‰ in warm season. Cave air is interpreted as a result of a mix between external air and an isotopically depleted air, coming from the rock environment. The isotopic value of the light member varies through time, from -23.9 to -22.5 ‰. Furthermore, this study ascertains that the cave never stops in communicating with the external air. The ventilation regime is identified. (1) In cold season, the cave inhales at night and blows a little at the warmest hours. However, in warm season, (2) cave blows at night, but (3) during the day, a convection loop takes place in the entrance area and prevents the external air from entering the cave, confirming the cold air trap.

  13. Probing magnetic bottom and crustal temperature variations along the Red Sea margin of Egypt

    Science.gov (United States)

    Ravat, D.; Salem, A.; Abdelaziz, A.M.S.; Elawadi, E.; Morgan, P.

    2011-01-01

    Over 50 magnetic bottom depths derived from spectra of magnetic anomalies in Eastern Egypt along the Red Sea margin show variable magnetic bottoms ranging from 10 to 34. km. The deep magnetic bottoms correspond more closely to the Moho depth in the region, and not the depth of 580??C, which lies significantly deeper on the steady state geotherms. These results support the idea of Wasilewski and coworkers that the Moho is a magnetic boundary in continental regions. Reduced-to-pole magnetic highs correspond to areas of Younger Granites that were emplaced toward the end of the Precambrian. Other crystalline Precambrian units formed earlier during the closure of ocean basins are not strongly magnetic. In the north, magnetic bottoms are shallow (10-15. km) in regions with a high proportion of these Younger Granites. In the south, the shoaling of the magnetic bottom associated with the Younger Granites appears to be restricted to the Aswan and Ras Banas regions. Complexity in the variation of magnetic bottom depths may arise due to a combination of factors: i) regions of Younger (Precambrian) Granites with high magnetite content in the upper crust, leaving behind low Curie temperature titanomagnetite components in the middle and lower crust, ii) rise in the depth of 580??C isotherm where the crust may have been heated due to initiation of intense magmatism at the time of the Red Sea rifting (~. 20. Ma), and iii) the contrast of the above two factors with respect to the neighboring regions where the Moho and/or Curie temperature truncates lithospheric ferromagnetism. Estimates of fractal and centroid magnetic bottoms in the oceanic regions of the Red Sea are significantly below the Moho in places suggesting that oceanic uppermost mantle may be serpentinized to the depth of 15-30 km in those regions. ?? 2011 Elsevier B.V.

  14. Subsurface temperature variations and heat flow in the Anambra Basin, Nigeria

    Science.gov (United States)

    Mosto Onuoha, K.; Ekine, Anthony S.

    1999-04-01

    Data from sixteen deep walls drilled for oil exploration purposes in the Anambra Basin of southeastern Nigeria indicate large variations in temperature gradients and heat flow within the basin. Geothermal gradients vary between 25 and 49 ± 1°C km -1, while heat flow estimates are in the range 48 to 76 ± 3 mW m -2. The highest geothermal gradients and heat flow values were computed for the wells located in the southwestern part of the basin north of Onitsha and Asaba. This part of the basin coincides with zones of thick, low conductivity sediments, low ground surface elevation, and hydraulic discharge zones. The general direction of increase in geothermal gradient, originally projected as south to north by earlier workers dealing with the Niger Delta data and the very limited well data from the Anambra Basin, is inconsistent with the results of the present study. The distribution of subsurface temperatures, geothermal gradients and heat flow is found to be directly related to the basin hydrodynamics - higher geothermal gradients and heat flow in areas of low hydraulic head distribution. Hydrocarbon metamorphism and migration appear to have been greatly influenced by the movements of circulating meteoric waters. A higher level of organic maturity of sediments should be expected in the southwestern zone, where the thermal anomaly exists. However, owing to hydrodynamic activities, tertiary migration would have taken place leaving many traces of residual hydrocarbons. The several cases of fluorescence noticed in wells in the southwestern zone of the Anambra Basin are taken as evidence that this process may indeed have taken place in the geological past of the basin.

  15. Impacts of early autumn Arctic sea ice concentration on subsequent spring Eurasian surface air temperature variations

    Science.gov (United States)

    Chen, Shangfeng; Wu, Renguang

    2017-11-01

    This study reveals a close relation between autumn Arctic sea ice change (SIC) in the Laptev Sea-eastern Siberian Sea-Beaufort Sea and subsequent spring Eurasian surface air temperature (SAT) variation. Specifically, more (less) SIC over the above regions in early autumn generally correspond to SAT warming (cooling) over the mid-high latitudes of Eurasia during subsequent spring. Early autumn Arctic SIC affects spring Eurasian SAT via modulating spring Arctic Oscillation (AO) associated atmospheric changes. The meridional temperature gradient over the mid-high latitudes decreases following the Arctic sea ice loss. This results in deceleration of prevailing westerly winds over the mid-latitudes of the troposphere, which leads to increase in the upward propagation of planetary waves and associated Eliassen-Palm flux convergence in the stratosphere over the mid-high latitudes. Thereby, westerly winds in the stratosphere are reduced and the polar vortex is weakened. Through the wave-mean flow interaction and downward propagation of zonal wind anomalies, a negative spring AO pattern is formed in the troposphere, which favors SAT cooling over Eurasia. The observed autumn Arctic SIC-spring Eurasian SAT connection is reproduced in the historical simulation (1850-2005) of the flexible global ocean-atmosphere-land system model, spectral version 2 (FGOALS-s2). The FGOALS-s2 also simulates the close connection between autumn SIC and subsequent spring AO. Further analysis suggests that the prediction skill of the spring Eurasian SAT was enhanced when taking the autumn Arctic SIC signal into account.

  16. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie

    2017-01-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.

  17. Variations in Surface Air Temperature Observations in the Arctic, 1979-97.

    Science.gov (United States)

    Rigor, Ignatius G.; Colony, Roger L.; Martin, Seelye

    2000-03-01

    The statistics of surface air temperature observations obtained from buoys, manned drifting stations, and meteorological land stations in the Arctic during 1979-97 are analyzed. Although the basic statistics agree with what has been published in various climatologies, the seasonal correlation length scales between the observations are shorter than the annual correlation length scales, especially during summer when the inhomogeneity between the ice-covered ocean and the land is most apparent. During autumn, winter, and spring, the monthly mean correlation length scales are approximately constant at about 1000 km; during summer, the length scales are much shorter, that is, as low as 300 km. These revised scales are particularly important in the optimal interpolation of data on surface air temperature (SAT) and are used in the analysis of an improved SAT dataset called International Arctic Buoy Programme/Polar Exchange at the Sea Surface (IABP/POLES). Compared to observations from land stations and the Russian North Pole drift stations, the IABP/POLES dataset has higher correlations and lower rms errors than previous SAT fields and provides better temperature estimates, especially during summer in the marginal ice zones. In addition, the revised correlation length scales allow data taken at interior land stations to be included in the optimal interpretation analysis without introducing land biases to grid points over the ocean. The new analysis provides 12-h fields of air temperatures on a 100-km rectangular grid for all land and ocean areas of the Arctic region for the years 1979-97.The IABP/POLES dataset is then used to study spatial and temporal variations in SAT. This dataset shows that on average melt begins in the marginal seas by the first week of June and advances rapidly over the Arctic Ocean, reaching the pole by 19 June, 2 weeks later. Freeze begins at the pole on 16 August, and the freeze isotherm advances more slowly than the melt isotherm. Freeze returns

  18. Variation in aeolian environments recorded by the particle size distribution of lacustrine sediments in Ebinur Lake, northwest China.

    Science.gov (United States)

    Ma, Long; Wu, Jinglu; Abuduwaili, Jilili

    2016-01-01

    Particle size analysis of lacustrine core sediments and atmospheric natural dust were conducted in the drainage area of Ebinur Lake in arid northwest China. Using a combination of (137)Cs and (210)Pb dating, a continuous record of aeolian transportation to the lake sediments and related factors over about the past 150 years was analyzed. Factor analysis revealed the particle-size distributions of riverine and aeolian sediments composed of the terrigenous materials of the lake deposits. Compared with the grain-size distributions of natural dust samples, the results showed that the coarser particle size fraction of lake sediments was mainly derived from the sediments that had experienced aeolian transport to the drainage surface, and the finer sediments came from hydraulic inputs. Then, the method of variations in particle-size standard deviation was used to extract the grain size intervals with the highest variability along a sedimentary sequence. The coarser grain-size populations dominated the variation patterns of the sedimentary sequence. During the last 150 years, strong intensity aeolian transportation occurred during three periods, 1915-1935, 1965-1975 and since the beginning of the 2000s. The climate was dry around 1910s-1930s in this region associated with the appropriate dynamic condition, which provided the enhanced source materials and wind power for the aeolian dust transport. Since 1950s, the climate controlled the foundation of aeolian dust transport, and the aeolian dust transport won't be increased under the humid climate.

  19. Effect of a huge crustal conductivity anomaly on the H-component of geomagnetic variations recorded in central South America

    Science.gov (United States)

    Padilha, Antonio L.; Alves, Livia R.; Silva, Graziela B. D.; Espinosa, Karen V.

    2017-04-01

    We describe here an analysis of the H-component of the geomagnetic field recorded in several temporary stations operating simultaneously in the central-eastern region of Brazil during nighttime pulsation events in 1994 and the sudden commencement of the St. Patrick's Day magnetic storm in 2015. A significant amplification in the amplitude of the geomagnetic variations is consistently observed in one of these stations. Magnetovariational analysis indicates that the amplification factor is period dependent with maximum amplitude around 100 s. Integrated magnetotelluric (MT) and geomagnetic depth soundings (GDS) have shown that this station is positioned just over a huge 1200-km-long crustal conductor (estimated bulk conductivity greater than 1 S/m). We propose that the anomalous signature of the geomagnetic field at this station is due to the high reflection coefficient of the incident electromagnetic wave at the interface with the very good conductor and by skin effects damping the electromagnetic wave in the conducting layers overlying the conductor. There are some indication from the GDS data that the conductor extends southward beneath the sediments of the Pantanal Basin. In this region is being planned the installation of a new geomagnetic observatory, but its preliminary data suggest anomalous geomagnetic variations. We understand that a detailed MT survey must be carried out around the chosen observatory site to evaluate the possible influence of induced currents on the local geomagnetic field.[Figure not available: see fulltext.

  20. A system for precise temperature control of isolated nervous tissue under optical access: application to multi-electrode recordings.

    Science.gov (United States)

    Ahlers, Malte T; Ammermüller, Josef

    2013-09-30

    Since temperature severely affects all physiological processes, exact temperature control during electrophysiological measurements is indispensable. However, none of the tempering system approaches previously described is fully satisfactory for extracellular recordings with sharp multi-electrode arrays (MEAs). We developed a set-up offering a homogeneously tempered and at the same time light-transparent stage for an ex vivo preparation. The Peltier element based tempering unit of our system is physically separated from the preparation stage avoiding electrical disturbances of extracellular recordings. We implemented a digital feedback controller on a microcontroller to minimise the deviation between actual and set point temperature. Our tempering system allows operation from 10°C to 45°C with a control error in steady state between 0.052°C (RMSE) and 0.115°C (RMSE). To document the versatility of our system, we performed extracellular MEA recordings from retinal ganglion cells of isolated retina under different temperature conditions. We found strong influences on light response properties, even for small temperature changes. Currently used heating systems that allow top and bottom side optical access to a preparation typically exhibit low temperature accuracy, precision or homogeneity. Our system is adequate not only for experiments on a variety of species under physiological temperature conditions but also for studies on temperature effects on physiology in general. Though the setup was developed for the context of MEA recordings from retina it may be useful in other cases where optical access to the preparation from both, top and bottom side is required. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Variation in the immune state of Gammarus pulex (Crustacea, Amphipoda) according to temperature: Are extreme temperatures a stress?

    Science.gov (United States)

    Labaude, Sophie; Moret, Yannick; Cézilly, Frank; Reuland, Charel; Rigaud, Thierry

    2017-11-01

    Temperature is known to impact host-parasite interactions in various ways. Such effects are often regarded as the consequence of the increased metabolism of parasites with increasing temperature. However, the effect of temperature on hosts' immune system could also be a determinant. Here we assessed the influence of temperature on the immunocompetence of the crustacean amphipod Gammarus pulex. Amphipods play a key ecological role in freshwater ecosystems that can be altered by several parasites. We investigated the consequences of three weeks of acclimatization at four temperatures (from 9 °C to 17 °C) on different immunological parameters. Temperature influenced both hemocyte concentration and active phenoloxidase enzymatic activity, with lower values at intermediate temperatures, while total phenoloxidase activity was not affected. In addition, the ability of gammarids to clear a bacterial infection was at the highest at intermediate temperatures. These results suggest a dysregulation of the immune system of gammarids in response to stress induced by extreme temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Diffusion Filters for Variational Data Assimilation of Sea Surface Temperature in an Intermediate Climate Model

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    2015-01-01

    Full Text Available Sequential, adaptive, and gradient diffusion filters are implemented into spatial multiscale three-dimensional variational data assimilation (3DVAR as alternative schemes to model background error covariance matrix for the commonly used correction scale method, recursive filter method, and sequential 3DVAR. The gradient diffusion filter (GDF is verified by a two-dimensional sea surface temperature (SST assimilation experiment. Compared to the existing DF, the new GDF scheme shows a superior performance in the assimilation experiment due to its success in extracting the spatial multiscale information. The GDF can retrieve successfully the longwave information over the whole analysis domain and the shortwave information over data-dense regions. After that, a perfect twin data assimilation experiment framework is designed to study the effect of the GDF on the state estimation based on an intermediate coupled model. In this framework, the assimilation model is subject to “biased” initial fields from the “truth” model. While the GDF reduces the model bias in general, it can enhance the accuracy of the state estimation in the region that the observations are removed, especially in the South Ocean. In addition, the higher forecast skill can be obtained through the better initial state fields produced by the GDF.

  3. Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat

    OpenAIRE

    Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

    2016-01-01

    We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes)...

  4. Decadal-scale variations of sedimentary dinoflagellate cyst records from the Yellow Sea over the last 400 years

    Science.gov (United States)

    Kim, So-Young; Roh, Youn Ho; Shin, Hyeon Ho; Huh, Sik; Kang, Sung-Ho; Lim, Dhongil

    2018-01-01

    In recent decades, the Yellow Sea has experienced severe environmental deterioration due to increasing input of anthropogenic pollutants and consequently accelerated eutrophication. Whilst there have been significant advances in documenting historical records of metal pollution in the Yellow Sea region, changes in phytoplankton community structures affected by eutrophication remain understudied. Here, we present a new record of dinoflagellate cyst-based signals in age-dated sediment cores from the Yellow Sea mud deposits to provide better insight into eutrophication history and identification of associated responses of the regional phytoplankton community. It is worthy of note that there were significant variations in abundances and community structures of dinoflagellate cysts in three historical stages in association with increasing anthropogenic activity over the last 400 years. Pervasive effects of human interference altering the Yellow Sea environments are recognized by: 1) an abrupt increase of organic matter, including the diatom-produced biogenic opal concentrations (∼1850); 2) a distinct shift in phytoplankton composition towards dinoflagellate dominance (∼1940), and 3) recent acceleration of dinoflagellate cyst accumulation (∼1990). Particularly in the central Yellow Sea shelf, the anomalously high deposition of dinoflagellate cysts (especially Alexandrium species) is suggested to be a potentially important source of inoculum cells serving as a seed population for localized and recurrent blooms in coastal areas around the Yellow Sea.

  5. The anatomy of Last Glacial Maximum climate variations in south Westland, New Zealand, derived from pollen records

    Science.gov (United States)

    Vandergoes, Marcus J.; Newnham, Rewi M.; Denton, George H.; Blaauw, Maarten; Barrell, David J. A.

    2013-08-01

    Westland occurred sometime between ca 18,490 and ca 17,370 cal. yr BP. A similar general pattern of stadials and interstadials is seen, to varying degrees of resolution but generally with lesser chronological control, in many other paleoclimate proxy records from the New Zealand region. This highly resolved chronology of vegetation changes from southwestern New Zealand contributes to the examination of past climate variations in the southwest Pacific region. The stadial and interstadial episodes defined by south Westland pollen records represent notable climate variability during the latter part of the Last Glaciation. Similar climatic patterns recorded farther afield, for example from Antarctica and the Southern Ocean, imply that climate variations during the latter part of the Last Glaciation and the transition to the Holocene interglacial were inter-regionally extensive in the Southern Hemisphere and thus important to understand in detail and to place into a global context.

  6. Seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese studied by home measurements.

    Science.gov (United States)

    Kimura, Toshiaki; Senda, Shoichi; Masugata, Hisashi; Yamagami, Ayumu; Okuyama, Hiroyuki; Kohno, Takeaki; Hirao, Tomohiro; Fukunaga, Megumu; Okada, Hiroki; Goda, Fuminori

    2010-01-01

    The purpose of the present study was to examine seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese, as studied by home measurements. Fifteen healthy elderly Japanese (79.3 +/- 5.9 yrs) measured their blood pressure at home each morning for more than 25 times per month for 3 years. Monthly mean outdoor temperatures were obtained from the Takamatsu meteorological Observatory. The highest levels of systolic and diastolic blood pressure measured at home were observed in February (129 +/- 14 and 81 +/- 13 mmHg). The lowest levels of systolic and diastolic blood pressure measured at home were observed in August (117 +/- 11 and 73 +/- 10 mmHg). Likewise, the lowest and highest means of outdoor temperature were observed in February (5.0 degrees C) and August (29.2 degrees C), respectively. Hence, both systolic and diastolic blood pressure demonstrated a close inverse correlation with the means of outdoor temperature (r = -0.973, p blood pressure (SBP) and 0.29 mmHg in diastolic blood pressure (DBP). Seasonal variations in home blood pressure and outdoor temperature showed complete correspondence in healthy elderly Japanese, with the blood pressures being inversely related to the ambient temperature. These seasonal home blood pressure variations should be kept in mind when controlling blood pressure in elderly patients.

  7. Quantifying the Impact of Land Cover Composition on Intra-Urban Air Temperature Variations at a Mid-Latitude City

    Science.gov (United States)

    Yan, Hai; Fan, Shuxin; Guo, Chenxiao; Hu, Jie; Dong, Li

    2014-01-01

    The effects of land cover on urban-rural and intra-urban temperature differences have been extensively documented. However, few studies have quantitatively related air temperature to land cover composition at a local scale which may be useful to guide landscape planning and design. In this study, the quantitative relationships between air temperature and land cover composition at a neighborhood scale in Beijing were investigated through a field measurement campaign and statistical analysis. The results showed that the air temperature had a significant positive correlation with the coverage of man-made surfaces, but the degree of correlation varied among different times and seasons. The different land cover types had different effects on air temperature, and also had very different spatial extent dependence: with increasing buffer zone size (from 20 to 300 m in radius), the correlation coefficient of different land cover types varied differently, and their relative impacts also varied among different times and seasons. At noon in summer, ∼37% of the variations in temperature were explained by the percentage tree cover, while ∼87% of the variations in temperature were explained by the percentage of building area and the percentage tree cover on summer night. The results emphasize the key role of tree cover in attenuating urban air temperature during daytime and nighttime in summer, further highlighting that increasing vegetation cover could be one effective way to ameliorate the urban thermal environment. PMID:25010134

  8. Quantifying the impact of land cover composition on intra-urban air temperature variations at a mid-latitude city.

    Science.gov (United States)

    Yan, Hai; Fan, Shuxin; Guo, Chenxiao; Hu, Jie; Dong, Li

    2014-01-01

    The effects of land cover on urban-rural and intra-urban temperature differences have been extensively documented. However, few studies have quantitatively related air temperature to land cover composition at a local scale which may be useful to guide landscape planning and design. In this study, the quantitative relationships between air temperature and land cover composition at a neighborhood scale in Beijing were investigated through a field measurement campaign and statistical analysis. The results showed that the air temperature had a significant positive correlation with the coverage of man-made surfaces, but the degree of correlation varied among different times and seasons. The different land cover types had different effects on air temperature, and also had very different spatial extent dependence: with increasing buffer zone size (from 20 to 300 m in radius), the correlation coefficient of different land cover types varied differently, and their relative impacts also varied among different times and seasons. At noon in summer, ∼ 37% of the variations in temperature were explained by the percentage tree cover, while ∼ 87% of the variations in temperature were explained by the percentage of building area and the percentage tree cover on summer night. The results emphasize the key role of tree cover in attenuating urban air temperature during daytime and nighttime in summer, further highlighting that increasing vegetation cover could be one effective way to ameliorate the urban thermal environment.

  9. Experimental investigation on the effect of intake air temperature and air-fuel ratio on cycle-to-cycle variations of HCCI combustion and performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2011-04-15

    Combustion in HCCI engines is a controlled auto ignition of well-mixed fuel, air and residual gas. Since onset of HCCI combustion depends on the auto ignition of fuel/air mixture, there is no direct control on the start of combustion process. Therefore, HCCI combustion becomes unstable rather easily, especially at lower and higher engine loads. In this study, cycle-to-cycle variations of a HCCI combustion engine fuelled with ethanol were investigated on a modified two-cylinder engine. Port injection technique is used for preparing homogeneous charge for HCCI combustion. The experiments were conducted at varying intake air temperatures and air-fuel ratios at constant engine speed of 1500 rpm and P-{theta} diagram of 100 consecutive combustion cycles for each test conditions at steady state operation were recorded. Consequently, cycle-to-cycle variations of the main combustion parameters and performance parameters were analyzed. To evaluate the cycle-to-cycle variations of HCCI combustion parameters, coefficient of variation (COV) of every parameter were calculated for every engine operating condition. The critical optimum parameters that can be used to define HCCI operating ranges are 'maximum rate of pressure rise' and 'COV of indicated mean effective pressure (IMEP)'. (author)

  10. Modelling the influence of urbanization on the 20th century temperature record of weather station De Bilt (The Netherlands)

    NARCIS (Netherlands)

    Koopmans, S.; Theeuwes, N.E.; Steeneveld, G.J.; Holtslag, A.A.M.

    2015-01-01

    Many cities have expanded during the 20th century, and consequently some weather stations are currently located closer to cities than before. Due to the urban heat island (UHI) effect, those weather stations may show a positive bias in their 2-m temperature record. In this study, we estimate the

  11. Effects of temperature, genetic variation and species competition on the sensitivity of algae populations to the antibiotic enrofloxacin

    NARCIS (Netherlands)

    Rico, Andreu; Zhao, Wenkai; Gillissen, Frits; Lürling, Miquel; Brink, van den Paul J.

    2018-01-01

    Primary producers are amongst the most sensitive organisms to antibiotic pollution in aquatic ecosystems. To date, there is little information on how different environmental conditions may affect their sensitivity to antibiotics. In this study we assessed how temperature, genetic variation and

  12. Geographic variation in thermal traits in Digenea simplex and Champia parvula (Rhodophyta) in relation to present and glacial temperature regimes

    NARCIS (Netherlands)

    Orfanidis, S; Breeman, AM

    1999-01-01

    Geographic variation in temperature responses (survival and growth) was investigated in two red algae: Digenea simplex (Wulfen) C. Agardh and Champia parvula (C. Agardh) Harvey. D. simplex has a tropical to warm temperate distribution; C. parvula extends from the tropics into the cold temperate

  13. Spatiotemporal analysis of temperature-variation patterns under climate change in the upper reach of Mekong River basin.

    Science.gov (United States)

    Wu, Feifei; Wang, Xuan; Cai, Yanpeng; Yang, Zhifeng; Li, Chunhui

    2012-06-15

    Occurrence of temperature anomaly has greatly affected natural cycles of water resources in Lancang River basin in China, which is the upper reach of Mekong River. An integrated spatiotemporal decomposition and analysis method was proposed for the identification of temperature-variation patterns under changing climatic conditions in the basin. This method was based on the combination of S-mode empirical orthogonal function analysis, IDW interpolation, liner regression, weighted moving average and Mann Kendall methods. Results indicated that the first two modes extracted nearly 80% of spatiotemporal variations in temperature. Temperature in the whole basin followed the same variation trend through the first mode analysis. Sensitive areas were mainly located in the southwest of the basin, which occupied nearly half of the basin. The associated time series presented that the basin appeared transition from cold periods to warm periods. Temperature increased significantly over the period of 1960 to 2009 at annual and seasonal scales, particularly over 1990s. At the same time, the most significant rising occurred in winter and the least in summer. In the second mode, a west-east inverse phase pattern of temperature variations was a distinct feature in most of the basin. Temporal trend indicated that the increasing trend in the west region was slightly stronger than that in the east. This was particularly the case of edge areas almost vertical juncture with monsoons. This research is not only helpful in improving understanding of temperature response to global warming in the basin but also provides a basis for basin management. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Temperature - Impact of chiller failure on the short-term temperature variation in the incubation of salmonids

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In salmon recovery programs it is commonly necessary to chill incubation and early rearing temperatures to match wild development times. The most common failure mode...

  15. Pressure and temperature variation of octahedral Na and tetrahedral Al in amphiboles in metamafic rocks

    Science.gov (United States)

    Jenkins, D. M.; Lei, J.

    2013-12-01

    The sodium content in the M4 site of amphibole (BNa) was calibrated by Brown (1977, J Petrol, 18, 53-72) in a study that continues to be highly cited to this day. This study, based on empirical observations of amphibole compositional changes in the presence of the buffering assemblage plagioclase, chlorite, epidote, iron oxide, and water, demonstrated a systematic variation in the BNa and tetrahedral Al (TAl) content with pressure. Recent experimental work in this lab aimed at defining the extent of miscibility along the tremolite-glaucophane and hornblende-glaucophane joins in the Na2O-CaO-MgO-Al2O3-SiO2-H2O system has provided some additional information on the cation mixing along these joins. These joins also serve as the chemically-simplified framework of the BNa versus TAl correlation reported by Brown (1977). There are now sufficient, though still a bare minimum, of experimentally-confirmed mixing data for sodium-rich amphiboles to test this correlation and for quantifying the pressure-temperature (P-T) dependence of amphibole compositions in metamafic rocks relevant to subduction zones. From experimental results obtained over the range of 500-800°C, 1.5-2.0 GPa, and using a variety of amphibole synthesis and re-equilibration methods, the following set of asymmetric formalism (ASF) macroscopic interaction and mixing parameters have been derived that can be used with THERMOCALC dataset 55: Wtrgl = 70 kJ, Wglts = Wtrts =20 kJ, α(tr) = 1.0, α(ts) = 1.2, and α(gl) = 0.52. Using a fixed MORB bulk composition, the composition of amphiboles within the P-T stability field of the buffering assemblage were calculated for the above chemical system with FeO added (i.e., NCFMASH) over the range of 0.2 - 2.0 GPa and 400 - 700°C. The following main observations can be made. First, the empirical amphibole compositions at low TAl and high BNa contents are well modeled by the miscibility gap in the amphibole ternary sub-system tremolite

  16. Spatiotemporal Variation and Abrupt Change Analysis of Temperature from 1960 to 2012 in the Huang-Huai-Hai Plain, China

    Directory of Open Access Journals (Sweden)

    Yanyu Yin

    2015-01-01

    Full Text Available Based on a monthly dataset of temperature time series (1960–2012 in the Huang-Huai-Hai Plain of China (HHHPC, spatiotemporal variation and abrupt change analysis of temperature were examined by moving average, linear regression, spline interpolation, Mann-Kendall test, and moving t-test. Major conclusions were listed as follows. (1 Annual and seasonal temperature increased with different rates on the process of fluctuating changes during 1960~2012. The upward trend was 0.22°C 10a−1 for annual temperature, while it was very significant in winter (0.34°C 10a−1 and spring (0.31°C 10a−1, moderately significant in autumn (0.21°C 10a−1, and nonsignificant in summer (0.05°C 10a−1. (2 The spatial changes of annual and seasonal temperature were similar. The temperature increased significantly in Beijing and its adjacent regions, while it was nonsignificant in the central and southern regions. (3 The spring, autumn, winter, and annual temperature had warm abrupt change. The abrupt change time for winter temperature was in the late 1970s, while it was in the late 1980s and early 1990s for spring, autumn, and annual temperature. (4 Macroscopic effects of global and regional climate warming and human activities were probably responsible for the temperature changes. The climate warming would influence the hydrological cycle and agricultural crops in the study area.

  17. The atmospheric muon flux in correlation with temperature variations in the low stratosphere (50-200 mb).

    Science.gov (United States)

    Bertaina, M.; Briatore, L.; Longhetto, A.; Navarra, G.; EAS-TOP collaboraiton

    The dependence of the muon flux from the atmospheric parameters (pressure and temperature) is a well known effect since long time ago, that is usually corrected for in cosmic ray measurements. We have correlated at EAS-TOP (LNGS) the muon flux detected by the EMD detector (29 stations, 10m2 each, E_thr>3MeV) with the atmospheric temperature (10-1000mb levels) monitored by the radio-soundings of the Aeronautica Militare at Pratica di Mare (Rome). A significant effect has been observed when the muon flux is correlated with the atmospheric temperature in the region 50-200mb (50-200gr/cm2), as expected, since this is the region where the mesons of first generation are produced. The effect becomes even larger (K_T=-9.5+/-1.1)x10-4 K-1) when the variations of the cosmic ray primary flux is taken into account (Neutron Monitor, Rome). Then, the technique has been used to monitor strong temperature variations in the low stratosphere through the muon flux in two periods, showing that the average temperature variations in the low stratosphere are reproduced with a ~2K uncertainty. The main results of this analysis will be presented.

  18. Development of a variational data assimilation system for the diurnal cycle of sea surface temperature

    Science.gov (United States)

    While, J.; Martin, M.

    2013-06-01

    A variational data assimilation system based on an incremental 4D-Var approach is proposed for use with a zero-dimensional model of the diurnal cycle of sea surface temperature (SST). Traditional 4D-Var, which seeks to find the initial state of a system, is not appropriate for diurnal SST which is a wind and heat flux driven system that has only a limited memory of its prior state. Instead the proposed assimilation system corrects both the initial SST and the heat and wind fluxes applied throughout the day. The assimilation system is tested using ensembles in a set of idealized twin experiments. In these tests controlling parameters are varied around reasonable "default" values with the quality of the analyses assessed against a known "truth". Within our tests data assimilation is shown to improve diurnal SST under most circumstances. Analyzed heat fluxes are also sometimes improved, although the improvement is much less than that observed for diurnal SST. The system was not found to improve the wind stress. The only circumstances where diurnal SST was not found to be improved by the assimilation were where either observational errors were large (greater than 0.5 K in our tests), or biases in the observations were too big (less than -0.3 K or greater than 0.2 K). The non-Gaussian behavior of the wind stress was found to have an impact on the assimilation in low-wind conditions and under these conditions the best analyses were obtained by artificially inflating the observation error.

  19. Crowdsourcing: It Matters Who the Crowd Are. The Impacts of between Group Variations in Recording Land Cover.

    Science.gov (United States)

    Comber, Alexis; Mooney, Peter; Purves, Ross S; Rocchini, Duccio; Walz, Ariane

    2016-01-01

    Volunteered geographical information (VGI) and citizen science have become important sources data for much scientific research. In the domain of land cover, crowdsourcing can provide a high temporal resolution data to support different analyses of landscape processes. However, the scientists may have little control over what gets recorded by the crowd, providing a potential source of error and uncertainty. This study compared analyses of crowdsourced land cover data that were contributed by different groups, based on nationality (labelled Gondor and Non-Gondor) and on domain experience (labelled Expert and Non-Expert). The analyses used a geographically weighted model to generate maps of land cover and compared the maps generated by the different groups. The results highlight the differences between the maps how specific land cover classes were under- and over-estimated. As crowdsourced data and citizen science are increasingly used to replace data collected under the designed experiment, this paper highlights the importance of considering between group variations and their impacts on the results of analyses. Critically, differences in the way that landscape features are conceptualised by different groups of contributors need to be considered when using crowdsourced data in formal scientific analyses. The discussion considers the potential for variation in crowdsourced data, the relativist nature of land cover and suggests a number of areas for future research. The key finding is that the veracity of citizen science data is not the critical issue per se. Rather, it is important to consider the impacts of differences in the semantics, affordances and functions associated with landscape features held by different groups of crowdsourced data contributors.

  20. Temporal δ13C records from bottlenose dolphins (Tursiops truncatus) reflect variation in foraging location and global carbon cycling

    Science.gov (United States)

    Rossman, S. L.; Barros, N. B.; Ostrom, P. H.; Gandhi, H.; Wells, R. S.

    2010-12-01

    With four decades of data on a population of bottlenose dolphins (Tursiops truncatus) resident to Sarasota Bay (SB), The Sarasota Dolphin Research Program offers an unparalleled platform for ground-truthing stable isotope data and exploring bottlenose dolphin ecology in a natural setting. We explored carbon isotope value fidelity to habitat utilization by comparing δ13C data from whole teeth and muscle to the individual dolphin's proclivity towards foraging in seagrass beds based on observational data. We then examined variation in habitat use based on temporal isotope records. Whole tooth protein isotope values do not show a significant correlation with the observed percentage of foraging in seagrass habitat. In contrast, δ13C values from muscle showed a significant positive relationship with the observational data. Differences in the degree of tissue turn over may account for this distinction between tooth and muscle. Dolphin teeth consist of annually deposited layers that are inert once formed. Thus, the isotopic composition of protein in annuli reflect foraging at the time of deposition. In addition to incorporating variation associated with differences in foraging over the lifetime of the individual, whole tooth isotope values are confounded because a disproportionate amount of tooth protein derives from the first few years of life. Given the turnover time of muscle tissue, isotope values reflect diet over the past several months. From 1991 to 2008, muscle δ13C values showed a significant decline, -13.5‰ to -15.1‰.This time period encompasses a state wide net fishing ban (1995) however other factors such as a series of red tide harmful algal blooms, a decline in predators, increases in shallow water boat traffic and an increase in string ray abundance may also contribute to the temporal isotope trend. To examine changes in dolphin foraging habitat further back in time we analyzed the tip of crown of the tooth which records the isotopic signal from the

  1. Impacts of interactive dust and its direct radiative forcing on interannual variations of temperature and precipitation in winter over East Asia: Impacts of Dust on IAVs of Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Sijia [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Yang, Yang [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Liu, Ying [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Singh, Balwinder [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Ghan, Steven J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2017-08-24

    We used 150-year pre-industrial simulations of the Community Earth System Model (CESM) to quantify the impacts of interactively-modeled dust emissions on the interannual variations of temperature and precipitation over East Asia during the East Asian Winter Monsoon (EAWM) season. The simulated December-January-February dust column burden and dust optical depth are lower over northern China in the strongest EAWM years than those of the weakest years, with regional mean values lower by 38.3% and 37.2%, respectively. The decrease in dust over the dust source regions (the Taklamakan and Gobi Deserts) and the downwind region (such as the North China Plain) leads to an increase in direct radiative forcing (RF) both at the surface and top of atmosphere by up to 1.5 and 0.75 W m-2, respectively. The effects of EAWM-related variations in surface winds, precipitation and their effects on dust emissions and wet removal contribute about 67% to the total dust-induced variations of direct RF at the surface and partly offset the cooling that occurs with the EAWM strengthening by heating the surface. The variations of surface air temperature induced by the changes in wind and dust emissions increase by 0.4-0.6 K over eastern coastal China, northeastern China, and Japan, which weakens the impact of EAWM on surface air temperature by 3–18% in these regions. The warming results from the combined effects of changes in direct RF and easterly wind anomalies that bring warm air from the ocean to these regions. Moreover, the feedback of the changes in wind on dust emissions weakens the variations of the sea level pressure gradient on the Siberian High while enhancing the Maritime Continent Low. Therefore, cold air is prevented from being transported from Siberia, Kazakhstan, western and central China to the western Pacific Ocean and decreases surface air temperature by 0.6 K and 2 K over central China and the Tibetan Plateau, respectively. Over eastern coastal China, the variations of

  2. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie N.

    2017-01-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates quality-control indicator during sample and drill-path selection when using long cores for SST paleoreconstruction. For our corals that passed this quality control step, the Sr/Ca-SST proxy performed well in estimating mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.Plain Language SummaryCoral skeletons are used to decipher past environmental conditions in the ocean because they live for centuries and produce annual growth bands much like tree rings. Along with measuring coral growth rates in the past, coral skeletons can be chemically sampled to get even more detailed information, like past seawater temperatures. In this study we tested the validity of the strontium-to-calcium (Sr/Ca) temperature proxy in the Massive Starlet Coral (Siderastrea siderea) by sampling 39 corals that were grown in the

  3. Inter-Seasonal Variations of Surface Temperature in the Urbanized Environment of Delhi Using Landsat Thermal Data

    Directory of Open Access Journals (Sweden)

    Ram Babu Singh

    2014-03-01

    Full Text Available Complex land use/cover patterns in urban areas significantly influence their prevailing surface temperature conditions. As a result of differential cooling and heating of various land use/cover, large temperature ranges are associated with bare land, built-up land, etc. and low ranges are found in vegetation cover and water bodies. Extremely high and low temperature conditions in built-up land have direct and negative impacts on health conditions, and therefore are imperative to study. Thus, an attempt has been made in this research to analyze seasonal variations in surface temperature in city of Delhi. Landsat Thematic Mapper (TM 5 satellite images for the four seasons, viz., 16 January (winter, 5 March (spring, 8 May (summer and 29 September (autumn 2011 have been used to interpret the distribution and changes in surface temperature. A total of 80 samples from all land use/cover categories were taken to generalize the patterns along with north-south and west-east profiles. The extracted surface temperature patterns reflect the spatial and temporal dynamics of temperature over different land use/cover. The north-south and west-east gradient of temperature demonstrates that the core of Delhi has a much lower temperature and weak urban heat island (UHI phenomenon.

  4. Elevation-Dependent Temperature Trends in the Rocky Mountain Front Range: Changes over a 56- and 20-Year Record

    Science.gov (United States)

    McGuire, Chris R.; Nufio, César R.; Bowers, M. Deane; Guralnick, Robert P.

    2012-01-01

    Determining the magnitude of climate change patterns across elevational gradients is essential for an improved understanding of broader climate change patterns and for predicting hydrologic and ecosystem changes. We present temperature trends from five long-term weather stations along a 2077-meter elevational transect in the Rocky Mountain Front Range of Colorado, USA. These trends were measured over two time periods: a full 56-year record (1953–2008) and a shorter 20-year (1989–2008) record representing a period of widely reported accelerating change. The rate of change of biological indicators, season length and accumulated growing-degree days, were also measured over the 56 and 20-year records. Finally, we compared how well interpolated Parameter-elevation Regression on Independent Slopes Model (PRISM) datasets match the quality controlled and weather data from each station. Our results show that warming signals were strongest at mid-elevations over both temporal scales. Over the 56-year record, most sites show warming occurring largely through increases in maximum temperatures, while the 20-year record documents warming associated with increases in maximum temperatures at lower elevations and increases in minimum temperatures at higher elevations. Recent decades have also shown a shift from warming during springtime to warming in July and November. Warming along the gradient has contributed to increases in growing-degree days, although to differing degrees, over both temporal scales. However, the length of the growing season has remained unchanged. Finally, the actual and the PRISM interpolated yearly rates rarely showed strong correlations and suggest different warming and cooling trends at most sites. Interpretation of climate trends and their seasonal biases in the Rocky Mountain Front Range are dependent on both elevation and the temporal scale of analysis. Given mismatches between interpolated data and the directly measured station data, we caution

  5. Elevation-dependent temperature trends in the Rocky Mountain Front Range: changes over a 56- and 20-year record.

    Directory of Open Access Journals (Sweden)

    Chris R McGuire

    Full Text Available Determining the magnitude of climate change patterns across elevational gradients is essential for an improved understanding of broader climate change patterns and for predicting hydrologic and ecosystem changes. We present temperature trends from five long-term weather stations along a 2077-meter elevational transect in the Rocky Mountain Front Range of Colorado, USA. These trends were measured over two time periods: a full 56-year record (1953-2008 and a shorter 20-year (1989-2008 record representing a period of widely reported accelerating change. The rate of change of biological indicators, season length and accumulated growing-degree days, were also measured over the 56 and 20-year records. Finally, we compared how well interpolated Parameter-elevation Regression on Independent Slopes Model (PRISM datasets match the quality controlled and weather data from each station. Our results show that warming signals were strongest at mid-elevations over both temporal scales. Over the 56-year record, most sites show warming occurring largely through increases in maximum temperatures, while the 20-year record documents warming associated with increases in maximum temperatures at lower elevations and increases in minimum temperatures at higher elevations. Recent decades have also shown a shift from warming during springtime to warming in July and November. Warming along the gradient has contributed to increases in growing-degree days, although to differing degrees, over both temporal scales. However, the length of the growing season has remained unchanged. Finally, the actual and the PRISM interpolated yearly rates rarely showed strong correlations and suggest different warming and cooling trends at most sites. Interpretation of climate trends and their seasonal biases in the Rocky Mountain Front Range are dependent on both elevation and the temporal scale of analysis. Given mismatches between interpolated data and the directly measured station data

  6. Effects of temporal variation in temperature and density dependence on insect population dynamics

    Science.gov (United States)

    Understanding effects of environmental variation on insect populations is important in light of predictions about increasing future climatic variability. In order to understand the effects of changing environmental variation on population dynamics and life history evolution in insects one would need...

  7. The simultaneous retrieval of surface evaporative fraction and heat transfer coefficients using variational data assimilation and surface radiometric temperature observations

    Science.gov (United States)

    Crow, W. T.; Kustas, W. P.

    2003-12-01

    Recent advances in land data assimilation have yielded data assimilation techniques designed to solve the surface energy balance based on remote observations of surface radiometric temperature and a simple prognostic equation for surface temperature. These approaches have a number of potential advantages over existing diagnostic models, including the ability to make energy flux predictions between satellite overpass times, more physically realistic representations of ground heat flux, and reduced requirements for ancillary parameter estimation. Of particular interest is the variational approach presented by Caparrini et al. (Journal of Hydrometeorology, 2003) which uses a force-restore equation for surface temperature as a constraint for the simultaneous estimation of both evaporative fraction and bulk heat transfer coefficients from sequences of surface radiometric temperature observations. Using eddy correlation flux tower data and analogous energy balance results obtained from the diagnostic Two-Source Model (TSM), this presentation will examine the performance of the Caparrini et al. algorithm over a range of vegetative and hydrologic conditions in the southern United States. Results identify circumstances under which the simultaneous - and unambiguous - retrieval of both surface evaporation fraction and heat transfer coefficients is possible and clarify parameter interpretation issues associated with the single-source geometry of the variational approach. Inter-comparison with the TSM model illustrates circumstances under which the increased parameter complexity of the TSM model is justified by its more accurate two-source representation of thermal emission from partial vegetation canopies. Potential improvements to current variational data assimilation techniques will also be discussed.

  8. Correcting the Cenozoic δ18O deep-sea temperature record

    NARCIS (Netherlands)

    Oerlemans, J.

    2004-01-01

    The oxygen isotope signal in benthic foraminifera from deep-sea cores is mainly determined by deep-ocean temperature and land ice volume. Separating the temperature and ice volume signals is a key step in understanding the evolution of Cenozoic climate. Except for the last few million years,

  9. Seasonal variation of nocturnal temperatures between 1 and 105 km altitude at 54° N observed by lidar

    Directory of Open Access Journals (Sweden)

    F.-J. Lübken

    2008-12-01

    Full Text Available Temperature soundings are performed by lidar at the mid-latitude station of Kühlungsborn (Germany, 54° N, 12° E. The profiles cover the complete range from the lower troposphere (~1 km to the lower thermosphere (~105 km by simultaneous and co-located operation of a Rayleigh-Mie-Raman lidar and a potassium resonance lidar. Observations have been done during 266 nights between June 2002 and July 2007, each of 3–15 h length. This large and unique data set provides comprehensive information on the altitudinal and seasonal variation of temperatures from the troposphere to the lower thermosphere. The remaining day-to-day-variability is strongly reduced by harmonic fits at constant altitude levels and a representative data set is achieved. This data set reveals a two-level mesopause structure with an altitude of about 86–87 km (~144 K in summer and ~102 km (~170 K during the rest of the year. The average stratopause altitude is ~48 km throughout the whole year, with temperatures varying between 258 and 276 K. From the fit parameters amplitudes and phases of annual, semi-annual, and quarter-annual variations are derived. The amplitude of the annual component is largest with amplitudes of up to 30 K in 85 km, while the quarter-annual variation is smallest and less than 3 K at all altitudes. The lidar data set is compared with ECMWF temperatures below about 70 km altitude and reference data from the NRLMSISE-00 model above. Apart from the temperature soundings the aerosol backscatter ratio is measured between 20 and 35 km. The seasonal variation of these values is presented here for the first time.

  10. [The relationship between the variation rate of MODIS land surface temperature and AMSR-E soil moisture and its application to downscaling].

    Science.gov (United States)

    Wang, An-Qi; Xie, Chao; Shi, Jian-Cheng; Gong, Hui-Li

    2013-03-01

    Using AMSR-E soil moisture, MODIS land surface temperature (Ts) and vegetation index product, the authors discuss the relationship between the variation rate of land surface temperature and surface soil moisture. Selecting the plains region of central United States as the study area, the authors propose the distribution triangle of the variation rate of land surface temperature and soil moisture. In the present paper, temperature variation and vegetation index (TVVI), a new index containing the information of temperature variation and vegetation, is introduced. The authors prove that TVVI and soil moisture show a steady relationship of exponential function; and build a quantitative model of soil moisture(SM) and instantaneous surface temperature variation (VTs). The authors later achieve downscaling of AMSR-E soil moisture data, through the above stated functional relationships and high-resolution MODIS data. Comparison with measured data on ground surface indicates that this method of downscaling is of high precision

  11. Temperature and its variations in birth rates and sex ratio in Greater ...

    African Journals Online (AJOL)

    That is, rates of conceptions among women generally, increase during relatively low temperature periods and vice versa. While female birth rates are negatively related with temperature, the reverse is the case with male births. This implies that the ratio of female birth decreases with increasing temperature whereas male ...

  12. Monitoring the body temperature of cows and calves using video recordings from an infrared thermography camera.

    Science.gov (United States)

    Hoffmann, Gundula; Schmidt, Mariana; Ammon, Christian; Rose-Meierhöfer, Sandra; Burfeind, Onno; Heuwieser, Wolfgang; Berg, Werner

    2013-06-01

    The aim of this study was to assess the variability of temperatures measured by a video-based infrared camera (IRC) in comparison to rectal and vaginal temperatures. The body surface temperatures of cows and calves were measured contactless at different body regions using videos from the IRC. Altogether, 22 cows and 9 calves were examined. The differences of the measured IRC temperatures among the body regions, i.e. eye (mean: 37.0 °C), back of the ear (35.6 °C), shoulder (34.9 °C) and vulva (37.2 °C), were significant (P infrared thermography videos has the advantage to analyze more than 1 picture per animal in a short period of time, and shows potential as a monitoring system for body temperatures in cattle.

  13. A Micro-Recorder for Measuring Skin Temperature and Sweating in Airplane Pilots

    Science.gov (United States)

    1943-12-01

    Other tabular groupings of data for individual students ars presented and the arerages disoussod* T* The records taksn in thsse preliminary... dato , time, recorder number, the exact time when the subject cot into the plane and started taxiing, the time when the plane landed, the time when...It seems possible to group the results and present them in tabular forme, The following Tables» 2 to 10 inclusive* are all similarly arranged* The re

  14. Variational assimilation of land surface temperature observations for enhanced river flow predictions

    Science.gov (United States)

    Ercolani, Giulia; Castelli, Fabio

    2016-04-01

    Data assimilation (DA) has the potential of improving hydrologic forecasts. However, many issues arise in case it is employed for spatially distributed hydrologic models that describes processes in various compartments: large dimensionality of the inverse problem, layers governed by different equations, non-linear and discontinuous model structure, complex topology of domains such as surface drainage and river network.On the other hand, integrated models offer the possibility of improving prediction of specific states by exploiting observations of quantities belonging to other compartments. In terms of forecasting river discharges, and hence for their enhancement, soil moisture is a key variable, since it determines the partitioning of rainfall into infiltration and surface runoff. However, soil moisture measurements are affected by issues that could prevent a successful DA and an actual improvement of discharge predictions.In-situ measurements suffer a dramatic spatial scarcity, while observations from satellite are barely accurate and provide spatial information only at a very coarse scale (around 40 km).Hydrologic models that explicitly represent land surface processes of coupled water and energy balance provide a valid alternative to direct DA of soil moisture.They gives the possibility of inferring soil moisture states through DA of remotely sensed Land Surface Temperature (LST), whose measurements are more accurate and with a higher spatial resolution in respect to those of soil moisture. In this work we present the assimilation of LST data in a hydrologic model (Mobidic) that is part of the operational forecasting chain for the Arno river, central Italy, with the aim of improving flood predictions. Mobidic is a raster based, continuous in time and distributed in space hydrologic model, with coupled mass and energy balance at the surface and coupled groundwater and surface hydrology. The variational approach is adopted for DA, since it requires less

  15. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  16. A large predatory reef fish species moderates feeding and activity patterns in response to seasonal and latitudinal temperature variation.

    Science.gov (United States)

    Scott, Molly; Heupel, Michelle; Tobin, Andrew; Pratchett, Morgan

    2017-10-11

    Climate-driven increases in ocean temperatures are expected to affect the metabolic requirements of marine species substantially. To mitigate the impacts of increasing temperatures in the short-term, it may be necessary for ectothermic organisms to alter their foraging behaviour and activity. Herein, we investigate seasonal variation in foraging behaviour and activity of latitudinally distinct populations of a large coral reef predator, the common coral trout, Plectropomus leopardus, from the Great Barrier Reef, Australia. P. leopardus exhibited increased foraging frequency in summer versus winter time, irrespective of latitude, however, foraging frequency substantially declined at water temperatures >30 °C. Foraging frequency also decreased with body size but there was no interaction with temperature. Activity patterns were directly correlated with water temperature; during summer, the low-latitude population of P. leopardus spent up to 62% of their time inactive, compared with 43% for the high-latitude population. The impact of water temperature on activity patterns was greatest for larger individuals. These results show that P. leopardus moderate their foraging behaviour and activity according to changes in ambient temperatures. It seems likely that increasing ocean temperatures may impose significant constraints on the capacity of large-bodied fishes to obtain sufficient prey resources while simultaneously conserving energy.

  17. Electrical Characterization of 4H-SiC JFET Wafer: DC Parameter Variations for Extreme Temperature IC Design

    Science.gov (United States)

    Neudeck, Philip G.; Chen, Liangyu; Spry, David J.; Beheim, Glenn M.; Chang, Carl W.

    2014-01-01

    This work reports DC electrical characterization of a 76 mm diameter 4H-SiC JFET test wafer fabricated as part of NASA's on-going efforts to realize medium-scale ICs with prolonged and stable circuit operation at temperatures as high as 500 degC. In particular, these measurements provide quantitative parameter ranges for use in JFET IC design and simulation. Larger than expected parameter variations were observed both as a function of position across the wafer as well as a function of ambient testing temperature from 23 degC to 500 degC.

  18. Long-term temperature variation of the Southern Yellow Sea Cold Water Mass from 1976 to 2006

    Science.gov (United States)

    Li, Ang; Yu, Fei; Si, Guangcheng; Wei, Chuanjie

    2017-09-01

    This paper discusses the long-term temperature variation of the Southern Yellow Sea Cold Water Mass (SYSCWM) and examines those factors that influence the SYSCWM, based on hydrographic datasets of the China National Standard Section and the Korea Oceanographic Data Center. Surface air temperature, meridional wind speed, and sea surface temperature data are used to describe the seasonal changes. Mean temperature of the two centers of the SYSCWM had diff erent long-term trends. The temperature of the center in the west of the SYSCWM was rising whereas that of the center in the east was falling. Mean temperature of the western center was related to warm water intrusion of the Yellow Sea Warm Current, the winter meridional wind, and the winter air temperature. Summer process played a primary role in the cooling trend of temperature in the eastern center. A decreasing trend of salinity in the eastern half of the SYSCWM showed that warm water intrusion from the south might weaken, as could the SYSCWM circulation. Weakened circulation provided less horizontal heat input to the eastern half of the SYSCWM. Less lateral heat input may have led to the decreasing trend in temperature of the eastern center of the SYSCWM. Further, warmer sea surface temperatures and less heat input in the deep layers intensified the thermocline of the eastern SYSCWM. A stronger thermocline had less heat flux input from upper layers to this half of the SYSCWM. Stronger thermocline and weakened heat input can be seen as two main causes of the cooling temperature trend of the eastern center of the SYSCWM.

  19. Generic calibration of a simple model of diurnal temperature variations for spatial analysis of accumulated degree-days

    Science.gov (United States)

    Felber, Raphael; Stoeckli, Sibylle; Calanca, Pierluigi

    2017-12-01

    Accumulated growing degree-days (aGDD) are widely used to predict phenological stages of plants and insects. It has been shown in the past that the best predictive performance is obtained when aGDD are computed from hourly temperature data. As the latter are not always available, models of diurnal temperature changes are often employed to retrieve the required information from data of daily minimum and maximum temperatures. In this study, we examine the performance of a well-known model of hourly temperature variations in the context of a spatial assessment of aGDD. Specifically, we examine whether a generic calibration of such a temperature model is sufficient to infer in a reliable way spatial patterns of key phenological stages across the complex territory of Switzerland. Temperature data of a relatively small number of meteorological stations is used to obtain a generic model parameterization, which is first compared with site-specific calibrations. We show that, at the local scale, the predictive skill of the generic model does not significantly differ from that of the site-specific models. We then show that for aGDD up to 800 °C d (on a base temperature of 10 °C), phenological dates predicted with aGDD obtained from estimated hourly temperature data are within ± 3 days of dates estimated on the basis of observed hourly temperatures. This suggests the generic calibration of hourly temperature models is indeed a valid approach for pre-processing temperature data in regional studies of insect and plant phenology.

  20. NOAA Climate Data Record for Mean Layer Temperature (Lower Stratosphere) from UCAR, Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Temperatures in the Lower Stratosphere (TLS) (AMSU channel 9 and MSU channel 4) CDR is generated by using National Oceanic and Atmospheric Administration (NOAA),...

  1. Record high magnetic ordering temperature in a lanthanide at extreme pressure

    Science.gov (United States)

    Lim, J.; Fabbris, G.; Haskel, D.; Schilling, J. S.

    2017-10-01

    Today’s best permanent magnet materials, SmCo5 and Nd2Fe14B, could likely be made significantly more powerful were it not necessary to dilute the strong magnetism of the rare earth ions (Sm, Nd) with the 3d transition elements (Fe, Co). Since the rare-earth metals order magnetically at relatively low temperatures T o ≤ 292 K, transition elements must be added to bring T o to temperatures well above ambient. Under pressure T o (P) for the neighboring lanthanides Gd, Tb, and Dy follows a notably nonmonotonic, but nearly identical, dependence to ∼60 GPa. At higher pressures, however, Tb and Dy exhibit highly anomalous behavior, T o for Dy soaring to temperatures well above ambient. We suggest that this anomalously high magnetic ordering temperature is an heretofore unrecognized feature of the Kondo lattice state.

  2. NOAA Climate Data Record (CDR) of MSU Level 1c Brightness Temperature, Version 1.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains Level 1c inter-calibrated brightness temperatures from the Microwave Sounding Unit (MSU) sensors onboard nine polar orbiting satellites...

  3. NOAA Climate Data Record for Mean Layer Temperature (Upper Troposphere & Lower Stratosphere) from UCAR, Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Temperatures of Troposphere / Stratosphere (TTS) (AMSU channel 7 and MSU channel 3) CDR is generated by using National Oceanic and Atmospheric Administration...

  4. Three centuries of temperature records in Scotland preserved in sclerochronological archives from freshwater pearl mussels, Margaritifera margaritifera (Linnaeus, 1758)

    Science.gov (United States)

    Pannell, C. L., ,, Dr; Fallick, A. E., ,, Prof.

    2009-04-01

    Bivalves are natural indicators of environmental variability as they reflect environmental conditions such as temperature in growth bands within the shell. During the winter period in temperate climes, shell growth ceases owing to the low water temperature and limited food supply. This hiatus is revealed by chemical staining as a very distinct etch-resistant band - termed the winter line. Winter lines alternate with less etch-resistant bands thus providing a chronology for any analyses which can be correlated to other proxy series and instrumental data. Freshwater pearl mussels have also been shown to form their shells in oxygen isotopic equilibrium with the ambient water thus fluctuations in water temperature can be constrained from the ^18Ocarbonatedata. As long as the date of collection is known, annual growth increments provide a precise dating tool for isotope samples and allow the allocation of precise calendar years to each part of the shell. Measurements of consecutive increments serve as records of isotopic composition from which derived temperatures may be correlated with other sample series and annual instrumental records, giving a high resolution proxy for temperature for a given region. ....... The use of live-collected M. margaritifera shells is now prohibited in the UK due to the mussel's rarity and its protection under the Wildlife and Countryside Act (1981) and the European Union Habitats and Species Directive (EUHSD). Museum collections of freshwater pearl mussels thus provide an invaluable resource, with many collections in UK museums having been live-collected during 19th century. As M. margaritifera is one of the longest-lived invertebrates, attaining an age of up to 140 years, sclerochronological and ^18Oaragonite data have the potential to provide terrestrial climate records on the centennial scale. The use of museum specimens has the potential to establish a composite three hundred year record of Scottish environmental change. Shells from

  5. Ranges of moisture-source temperature estimated from Antarctic ice cores stable isotope records over glacial–interglacial cycles

    Directory of Open Access Journals (Sweden)

    R. Uemura

    2012-06-01

    Full Text Available A single isotope ratio (δD or δ18O of water is widely used as an air-temperature proxy in Antarctic ice core records. These isotope ratios, however, do not solely depend on air-temperature but also on the extent of distillation of heavy isotopes out of atmospheric water vapor from an oceanic moisture source to a precipitation site. The temperature changes at the oceanic moisture source (Δ Tsource and at the precipitation site (Δ Tsite can be retrieved by using deuterium-excess (d data. A new d record from Dome Fuji, Antarctica spanning the past 360 000 yr is presented and compared with records from Vostok and EPICA Dome C ice cores. In previous studies, to retrieve Δ Tsource and Δ Tsite information, different linear regression equations were proposed using theoretical isotope distillation models. A major source of uncertainty lies in the coefficient of regression, βsite which is related to the sensitivity of d to Δ Tsite. We show that different ranges of temperature and selections of isotopic model outputs may increase the value of βsite by more than a factor of two. To explore the impacts of this coefficient on reconstructed temperatures, we apply for the first time the exact same methodology to the isotope records from the three Antarctica ice cores. We show that uncertainties in the βsite coefficient strongly affect (i the glacial–interglacial magnitude of Δ Tsource; (ii the imprint of obliquity in Δ Tsource and in the site-source temperature gradient. By contrast, we highlight the robustness of Δ Tsite reconstruction using water isotopes records.

  6. Reptilia, Squamata, Iguanidae, Anolis heterodermus Duméril, 1851: Distribution extension, first record for Ecuador and notes on color variation

    Directory of Open Access Journals (Sweden)

    Torres-Carvajal, O.

    2010-01-01

    Full Text Available We report the first record of A. heterodermus for Ecuador based on four specimens from Chilmá Bajo, province ofCarchi, ca. 120 km NE from the nearest record (departamento Putumayo, municipio de Santiago, Colombia reported in theliterature. Two additional records for Ecuador are listed in the Herpnet database, from specimens deposited at the CarnegieMuseum of Natural History and collected 18 km SE from Maldonado (ca. 8 km NW from Chilmá Bajo. We also presentinformation about color variation in the recently collected specimens.

  7. Global circuit response to seasonal variations in global surface air temperature

    Science.gov (United States)

    Williams, Earle R.

    1994-01-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  8. Wenatchee River, Washington, Water Temperature Modeling and Assessment Using Remotely Sensed Thermal Infrared and Instream Recorded Data

    Science.gov (United States)

    Cristea, N. C.; Burges, S. J.

    2004-12-01

    The stream water spatial and temporal temperature patterns of the Wenatchee River, WA are assessed based on temperature data recorded by instream data loggers in the dry season of 2002 and thermal infrared imagery from August 16th 2002. To gain insights into the possible thermal behavior of the river, the stream temperature model Qual2K (Chapra and Pelletier, 2003) is extended beyond its calibration (10-16 August 2002) and confirmation (9-11 September 2002) periods for use with different meteorological, shade and flow conditions. The temperature longitudinal profile of the Wenatchee River is influenced by the temperature regime in Lake Wenatchee, the source of the Wenatchee River. Model simulations performed at 7-day average with 2-year return period flow conditions show that the potential (maximum average across all reaches) temperature (the temperature that would occur under natural conditions) is about 19.8 deg. C. For the 7-day average with 10-year return period flow conditions the potential temperature increases to about 21.2 deg. C. The simulation results show that under normal flow and meteorological conditions the water temperature exceeds the current water quality standards. Model simulations performed under the 7-day average with 10-year return period flow conditions and a climate change scenario show that the average potential temperature across all reaches can increase by as much as 1.3 deg. C compared to the case where climate change impact is not taken into account. Thermal infrared (TIR) derived stream temperature data were useful for describing spatial distribution patterns of the Wenatchee River water temperature. The TIR and visible band images are effective tools to map cold water refugia for fish and to detect regions that can be improved for fish survival. The images collected during the TIR survey and the TIR derived stream temperature longitudinal profile helps pinpoint additional instream monitoring locations that avoid regions of backwater

  9. Variation in saltiness perception of soup with respect to soup serving temperature and consumer dietary habits.

    Science.gov (United States)

    Kim, Jeong-Weon; Samant, Shilpa S; Seo, Yoojin; Seo, Han-Seok

    2015-01-01

    Little is known about the effect of serving temperature on saltiness perception in food products such as soups that are typically consumed at high temperature. This study focused on determining whether serving temperature modulates saltiness perception in soup-base products. Eight trained panelists and 62 untrained consumers were asked to rate saltiness intensities in salt water, chicken broth, and miso soup, with serving temperatures of 40, 50, 60, 70, and 80 °C. Neither trained nor untrained panelists were able to find significant difference in the saltiness intensity among salt water samples served at these five different temperatures. However, untrained consumers (but not trained panelists) rated chicken broth and miso soup to be significantly less salty when served at 70 and/or 80 °C compared to when served at 40 to 60 °C. There was an interaction between temperature-related perceived saltiness and preference; for example, consumers who preferred soups served at lower temperatures found soups served at higher temperatures to be less salty. Consumers who frequently consumed hot dishes rated soup samples served at 60 °C as saltier than consumers who consumed hot dishes less frequently. This study demonstrates that soup serving temperature and consumer dietary habits are influential factors affecting saltiness perception of soup. Published by Elsevier Ltd.

  10. [The impact of air temperature variation on the visits to emergency room in Shanghai].

    Science.gov (United States)

    Dong, Ying; Zhao, Nai-Qing; Wang, Ai-Rong; Jia, Guang-Yi

    2009-01-01

    To assess the association between air temperature and emergency room visits among patients covered by medical care program from 'third-grade' hospitals in Shanghai. Generalized additive model (GAM) was used to analyze time series, and AR(P) was used to deal with auto correlation of time series. After controlling factors as both medium-term and long-term trends, day of the week, vocation, typical pneumonia and pollutants, the association between air temperature and emergency room visits in virtue of quadratic curve and differential coefficient principle were estimated. When air temperature was below 14.71 degrees C, the increase of 95% confidence interval to relative risk in corresponding emergency room visits along with 1 degree C increase of air temperature, was less than 1. However, when air temperature was above 19.59 degrees C, the relative risk's 95% confidence interval was greater than 1. When air temperature varied at the range of 14.71 degrees C-19.59 degrees C, the 95% confidence interval of the relative risk would include 1. Hence, air temperature range between 14.71 degrees C-19.59 degrees C, was called the optimum temperature range. Our findings indicated that the current air temperature had an acute impact on the number of emergency room visits among patients covered by medical care program visiting those third grade hospitals in Shanghai.

  11. Impact of precipitation intermittency on NAO-temperature signals in proxy records

    Directory of Open Access Journals (Sweden)

    M. Casado

    2013-03-01

    Full Text Available In mid and high latitudes, the stable isotope ratio in precipitation is driven by changes in temperature, which control atmospheric distillation. This relationship forms the basis for many continental paleoclimatic reconstructions using direct (e.g. ice cores or indirect (e.g. tree ring cellulose, speleothem calcite archives of past precipitation. However, the archiving process is inherently biased by intermittency of precipitation. Here, we use two sets of atmospheric reanalyses (NCEP (National Centers for Environmental Prediction and ERA-interim to quantify this precipitation intermittency bias, by comparing seasonal (winter and summer temperatures estimated with and without precipitation weighting. We show that this bias reaches up to 10 °C and has large interannual variability. We then assess the impact of precipitation intermittency on the strength and stability of temporal correlations between seasonal temperatures and the North Atlantic Oscillation (NAO. Precipitation weighting reduces the correlation between winter NAO and temperature in some areas (e.g. Québec, South-East USA, East Greenland, East Siberia, Mediterranean sector but does not alter the main patterns of correlation. The correlations between NAO, δ18O in precipitation, temperature and precipitation weighted temperature are investigated using outputs of an atmospheric general circulation model enabled with stable isotopes and nudged using reanalyses (LMDZiso (Laboratoire de Météorologie Dynamique Zoom. In winter, LMDZiso shows similar correlation values between the NAO and both the precipitation weighted temperature and δ18O in precipitation, thus suggesting limited impacts of moisture origin. Correlations of comparable magnitude are obtained for the available observational evidence (GNIP (Global Network of Isotopes in Precipitation and Greenland ice core data. Our findings support the use of archives of past δ18O for NAO reconstructions.

  12. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms.

    Science.gov (United States)

    Katiyatiya, C L F; Muchenje, V; Mushunje, A

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P cows had significantly longer (P tick loads on different body parts and heat stress in Nguni cows.

  13. Investigation of temperature and barometric pressure variation effects on radon concentration in the Sopronbánfalva Geodynamic Observatory, Hungary.

    Science.gov (United States)

    Mentes, Gyula; Eper-Pápai, Ildikó

    2015-11-01

    Radon concentration variation has been monitored since 2009 in the artificial gallery of the Sopronbánfalva Geodynamic Observatory, Hungary. In the observatory, the radon concentration is extremely high, 100-600 kBq m(-3) in summer and some kBq m(-3) in winter. The relationships between radon concentration, temperature and barometric pressure were separately investigated in the summer and winter months by Fast Fourier Transform, Principal Component Analysis, Multivariable Regression and Partial Least Square analyses in different frequency bands. It was revealed that the long-period radon concentration variation is mainly governed by the temperature (20 kBq m(-1) °C(-1)) both in summer and winter. The regression coefficients between long-period radon concentration and barometric pressure are -1.5 kBq m(-3) hPa(-1) in the summer and 5 kBq m(-3) hPa(-1) in the winter months. In the 0.072-0.48 cpd (cycles per day) frequency band the effect of the temperature is about -1 kBq m(-3) °C(-1) and that of the barometric pressure is -5 kBq m(-3) hPa(-1) in summer and -0.5 kBq m(-3) hPa(-1) in winter. In the high frequency range (>0.48 cpd) all regression coefficients are one order of magnitude smaller than in the range of 0.072-0.48 cpd. Fast Fourier Transform of the radon concentration, temperature and barometric pressure time series revealed S1, K1, P1, S2, K2, M2 tidal constituents in the data and weak O1 components in the radon concentration and barometric pressure series. A detailed tidal analysis, however, showed that the radon tidal components are not directly driven by the gravitational force but rather by solar radiation and barometric tide. Principal Component Analysis of the raw data was performed to investigate the yearly, summer and winter variability of the radon concentration, temperature and barometric pressure. In the summer and winter periods the variability does not change. The higher variability of the radon concentration compared to the variability of

  14. Effects of two types of clothing on the day-night variation of core temperature and salivary immunoglobulin A.

    Science.gov (United States)

    Park, S J; Tokura, H

    1997-11-01

    Circadian variations in core temperature, skin temperatures, heart rate, and salivary immunoglobulin A (IgA) were compared in subjects wearing two different types of clothing that covered, or left uncovered, their extremities. The experiments were carried out on six female subjects at an ambient temperature of 24 +/- 0.5 degrees C and relative humidity of 50 +/- 5%. One type of clothing consisted of long-sleeved shirts, full-length trousers, and socks (Type L: 1042 g, 1.048 clo); the other was half-sleeved shirts and knee-length trousers (Type H: 747 g, 0.744 clo). The main results were as follows: (i) The level of rectal temperature during night sleep was significantly lower with Type H than Type L clothing, and cosinor analysis indicated a significantly higher circadian amplitude with Type H clothing. (ii) Skin temperatures in the lower extremities increased significantly more on retiring to sleep with Type H than Type L clothing. (iii) Heart rate was significantly lower with Type H than Type L clothing during the sleep period. (iv) The day-night variation of salivary IgA showed a pattern that was the inverse of that of rectal temperature (i.e., low in the daytime and high in the nighttime), and the concentration of salivary IgA was significantly higher with Type H than Type L clothing at 02:30. (v) Subjectively, the self-assessed sleep quality was better with Type H clothing. These results suggest that clothing that leaves the extremities uncovered might be regarded as favorable at the moderate temperature since it induces good sleep and activates the immune response.

  15. A biomarker record of temperature and phytoplankton community in Okinawa Trough since the last glacial maximum

    Science.gov (United States)

    Ruan, Jiaping

    2017-04-01

    A variety of biomarkers were examined from Ocean Drilling Program (ODP) core 1202B to reconstruct temperature and phytoplankton community structures in the southern Okinawa Trough for the past ca. 20000 years. Two molecular temperature proxies (Uk37 and TEX86) show 5-6 ℃ warming during the glacial/interglacial transition. Prior to the Holocene, the Uk37-derived temperature was generally 1-4 ℃ higher than TEX86-derived temperature. This difference, however, was reduced to phytoplankton biomarkers (e.g., C37:2 alkenone, brassicasterol, C30 1,15-diols and dinosterol) suggest a shift of planktonic community assemblages with coccolithophorids becoming more abundant in the Holocene at the expense of diatoms/dinoflagellates. Such a shift is related to the variability of nutrient, temperature and salinity in the Okinawa Trough, controlled by the sea level and the intensity of Kuroshio Current. The phytoplankton community change may have profound implications on atmospheric CO2 fluctuations during glacial/interglacial cycles since diatoms and dinoflagellates have a higher efficiency of biological pump than coccolithophorids.

  16. High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution.

    Science.gov (United States)

    Lecavalier, Benoit S; Fisher, David A; Milne, Glenn A; Vinther, Bo M; Tarasov, Lev; Huybrechts, Philippe; Lacelle, Denis; Main, Brittany; Zheng, James; Bourgeois, Jocelyne; Dyke, Arthur S

    2017-06-06

    We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4-5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800-7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ∼1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland ice sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.

  17. Survival of Ixodes ricinus (Acari: Ixodidae) nymphs under cold conditions is negatively influenced by frequent temperature variations.

    Science.gov (United States)

    Herrmann, Coralie; Gern, Lise

    2013-09-01

    In this study, we tested the survival of Ixodes ricinus under cold conditions in the laboratory. We investigated how the frequency of temperature variations (from -5 °C or -10 °C to 13 °C), and infection with Borrelia burgdorferi sensu lato (s.l.) influenced survival of questing nymphs collected in spring and autumn 2011. In experiment 1, survival of 1760 nymphs was tested at -10 °C over a short period of time to simulate very cold winter conditions. In experiment 2, survival of 1600 nymphs was tested under cold condition (-5 °C) over a long period of time to simulate common winter conditions. Ticks used for survival tests at -5 °C were screened for Borrelia by quantitative PCR, and genospecies identification was achieved by reverse line blotting. Tick age and frequency of temperature variations had a highly significant effect on I. ricinus survival while Borrelia infection was marginally significant. Hence, survival rate was higher in younger (autumn) than older (spring) nymphs and in nymphs exposed to low rather than high-frequency temperature variations. Borrelia-infected ticks tended to survive better than their uninfected counterparts. These findings suggest that in nature (i) frequent temperature changes in winter threaten tick survival more importantly than very low temperatures, (ii) older (spring) ticks are less resistant to cold than younger (autumn) individuals, and (iii) Borrelia infection plays a marginal role in I. ricinus survival during winter conditions. Copyright © 2013 Elsevier GmbH. All rights reserved.

  18. Galileo SSI and Cassini ISS Observations of Io's Pele Hotspot: Temperatures, Areas, and Variation with Time

    Science.gov (United States)

    Radebaugh, J.; McEwen, A. S.; Milazzo, M.; Davies, A. G.; Keszthelyi, L. P.; Geissler, P.

    2002-01-01

    Temperatures of Io's Pele hotspot were found using dual-filter observations from Galileo and Cassini. Temperatures average 1375 K, but vary widely over tens of minutes. Dropoff in emission with rotation consistent with lava fountaining at a lava lake. Additional information is contained in the original extended abstract.

  19. Variation of the dielectric properties of chicken breast meet with frequency and temperature

    Science.gov (United States)

    Dielectric properties of chicken breast meat were measured with an open-ended coaxial-line probe between 200 MHz and 20 GHz at temperatures ranging from -20 oC to +25 oC. To ensure temperature uniformity between the different components of the measurement assembly, the measurements were performed in...

  20. Variation of the dielectric properties of chicken meat with frequency and temperature

    Science.gov (United States)

    Dielectric properties of chicken breast meat were measured with an open-ended coaxial-line probe between 200 MHz and 20 GHz at temperatures ranging from -20 degree C to +25 degree C. To ensure temperature uniformity between the different components of the measurement assembly, the measurements were ...

  1. Analysis of surface air temperature variations and local urbanization effects on central Yunnan Plateau, SW China

    Science.gov (United States)

    He, Yunling; Wu, Zhijie; Liu, Xuelian; Deng, Fuying

    2018-01-01

    With the surface air temperature (SAT) data at 37 stations on Central Yunnan Plateau (CYP) for 1961-2010 and the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime light data, the temporal-spatial patterns of the SAT trends are detected using Sen's Nonparametric Estimator of Slope approach and MK test, and the impact of urbanization on surface warming is analyzed by comparing the differences between the air temperature change trends of urban stations and their corresponding rural stations. Results indicated that annual mean air temperature showed a significant warming trend, which is equivalent to a rate of 0.17 °C/decade during the past 50 years. Seasonal mean air temperature presents a rising trend, and the trend was more significant in winter (0.31 °C/decade) than in other seasons. Annual/seasonal mean air temperature tends to increase in most areas, and higher warming trend appeared in urban areas, notably in Kunming city. The regional mean air temperature series was significantly impacted by urban warming, and the urbanization-induced warming contributed to approximately 32.3-62.9 % of the total regional warming during the past 50 years. Meantime, the urbanization-induced warming trend in winter and spring was more significant than that in summer and autumn. Since 1985, the urban heat island (UHI) intensity has gradually increased. And the urban temperatures always rise faster than rural temperatures on the CYP.

  2. Variations of body temperature and metabolism during entrance into cold lethargy in the bat Myotis myotis

    NARCIS (Netherlands)

    Heldmaier, Gerhard

    1970-01-01

    Bats of temperate zones which hibernate during winter become cold-lethargic during their diurnal rest time even in summer. At the end of their nocturnal activity period they show a drop in body temperature close to ambient temperature (M. myotis, cf. Pohl, 1961). This takes place periodically even

  3. Twentieth century sea surface temperature and salinity variations at Timor inferred from paired coral δ18O and Sr/Ca measurements

    Science.gov (United States)

    Cahyarini, Sri Yudawati; Pfeiffer, Miriam; Nurhati, Intan Suci; Aldrian, Edvin; Dullo, Wolf-Christian; Hetzinger, Steffen

    2014-07-01

    The Indonesian Throughflow (ITF), which represents the global ocean circulation connecting the Pacific Warm Pool to the Indian Ocean, strongly influences the Indo-Pacific climate. ITF monitoring since the late 1990s using mooring buoys have provided insights on seasonal and interannual time scales. However, the absence of longer records limits our perspective on its evolution over the past century. Here, we present sea surface temperature (SST) and salinity (SSS) proxy records from Timor Island located at the ITF exit passage via paired coral δ18O and Sr/Ca measurements spanning the period 1914-2004. These high-resolution proxy based climate data of the last century highlights improvements and cautions when interpreting paleoclimate records of the Indonesian region. If the seasonality of SST and SSS is not perfectly in phase, the application of coral Sr/Ca thermometry improves SST reconstructions compared to estimates based on coral δ18O only. Our records also underline the importance of ocean advection besides rainfall on local SSS in the region. Although the El Niño/Southern Oscillation (ENSO) causes larger anomalies relative to the Indian Ocean Dipole (IOD), Timor coral-based SST and SSS records robustly correlate with IOD on interannual time scales, whereas ENSO only modifies Timor SST. Similarly, Timor SST and SSS are strongly linked to Indian Ocean decadal-scale variations that appear to lead Timor oceanographic conditions by about 1.6-2 years. Our study sheds new light on the complex signatures of Indo-Pacific climate modes on SST and SSS dynamics of the ITF. This article was corrected on 8 AUG 2014. See the end of the full text for details.

  4. A probabilistic analysis of human influence on recent record global mean temperature changes

    Directory of Open Access Journals (Sweden)

    Philip Kokic

    2014-01-01

    Full Text Available December 2013 was the 346th consecutive month where global land and ocean average surface temperature exceeded the 20th century monthly average, with February 1985 the last time mean temperature fell below this value. Even given these and other extraordinary statistics, public acceptance of human induced climate change and confidence in the supporting science has declined since 2007. The degree of uncertainty as to whether observed climate changes are due to human activity or are part of natural systems fluctuations remains a major stumbling block to effective adaptation action and risk management. Previous approaches to attribute change include qualitative expert-assessment approaches such as used in IPCC reports and use of ‘fingerprinting’ methods based on global climate models. Here we develop an alternative approach which provides a rigorous probabilistic statistical assessment of the link between observed climate changes and human activities in a way that can inform formal climate risk assessment. We construct and validate a time series model of anomalous global temperatures to June 2010, using rates of greenhouse gas (GHG emissions, as well as other causal factors including solar radiation, volcanic forcing and the El Niño Southern Oscillation. When the effect of GHGs is removed, bootstrap simulation of the model reveals that there is less than a one in one hundred thousand chance of observing an unbroken sequence of 304 months (our analysis extends to June 2010 with mean surface temperature exceeding the 20th century average. We also show that one would expect a far greater number of short periods of falling global temperatures (as observed since 1998 if climate change was not occurring. This approach to assessing probabilities of human influence on global temperature could be transferred to other climate variables and extremes allowing enhanced formal risk assessment of climate change.

  5. Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats

    Science.gov (United States)

    Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

    2016-01-01

    Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming. PMID:27540589

  6. Plasticity of Performance Curves Can Buffer Reaction Rates from Body Temperature Variation in Active Endotherms.

    Science.gov (United States)

    Seebacher, Frank; Little, Alexander G

    2017-01-01

    Endotherms regulate their core body temperature by adjusting metabolic heat production and insulation. Endothermic body temperatures are therefore relatively stable compared to external temperatures. The thermal sensitivity of biochemical reaction rates is thought to have co-evolved with body temperature regulation so that optimal reaction rates occur at the regulated body temperature. However, recent data show that core body temperatures even of non-torpid endotherms fluctuate considerably. Additionally, peripheral temperatures can be considerably lower and more variable than core body temperatures. Here we discuss whether published data support the hypothesis that thermal performance curves of physiological reaction rates are plastic so that performance is maintained despite variable body temperatures within active (non-torpid) endotherms, and we explore mechanisms that confer plasticity. There is evidence that thermal performance curves in tissues that experience thermal fluctuations can be plastic, although this question remains relatively unexplored for endotherms. Mechanisms that alter thermal responses locally at the tissue level include transient potential receptor ion channels (TRPV and TRPM) and the AMP-activated protein kinase (AMPK) both of which can influence metabolism and energy expenditure. Additionally, the thermal sensitivity of processes that cause post-transcriptional RNA degradation can promote the relative expression of cold-responsive genes. Endotherms can respond to environmental fluctuations similarly to ectotherms, and thermal plasticity complements core body temperature regulation to increase whole-organism performance. Thermal plasticity is ancestral to endothermic thermoregulation, but it has not lost its selective advantage so that modern endotherms are a physiological composite of ancestral ectothermic and derived endothermic traits.

  7. Plasticity of Performance Curves Can Buffer Reaction Rates from Body Temperature Variation in Active Endotherms

    Directory of Open Access Journals (Sweden)

    Frank Seebacher

    2017-08-01

    Full Text Available Endotherms regulate their core body temperature by adjusting metabolic heat production and insulation. Endothermic body temperatures are therefore relatively stable compared to external temperatures. The thermal sensitivity of biochemical reaction rates is thought to have co-evolved with body temperature regulation so that optimal reaction rates occur at the regulated body temperature. However, recent data show that core body temperatures even of non-torpid endotherms fluctuate considerably. Additionally, peripheral temperatures can be considerably lower and more variable than core body temperatures. Here we discuss whether published data support the hypothesis that thermal performance curves of physiological reaction rates are plastic so that performance is maintained despite variable body temperatures within active (non-torpid endotherms, and we explore mechanisms that confer plasticity. There is evidence that thermal performance curves in tissues that experience thermal fluctuations can be plastic, although this question remains relatively unexplored for endotherms. Mechanisms that alter thermal responses locally at the tissue level include transient potential receptor ion channels (TRPV and TRPM and the AMP-activated protein kinase (AMPK both of which can influence metabolism and energy expenditure. Additionally, the thermal sensitivity of processes that cause post-transcriptional RNA degradation can promote the relative expression of cold-responsive genes. Endotherms can respond to environmental fluctuations similarly to ectotherms, and thermal plasticity complements core body temperature regulation to increase whole-organism performance. Thermal plasticity is ancestral to endothermic thermoregulation, but it has not lost its selective advantage so that modern endotherms are a physiological composite of ancestral ectothermic and derived endothermic traits.

  8. Plasticity of Performance Curves Can Buffer Reaction Rates from Body Temperature Variation in Active Endotherms

    Science.gov (United States)

    Seebacher, Frank; Little, Alexander G.

    2017-01-01

    Endotherms regulate their core body temperature by adjusting metabolic heat production and insulation. Endothermic body temperatures are therefore relatively stable compared to external temperatures. The thermal sensitivity of biochemical reaction rates is thought to have co-evolved with body temperature regulation so that optimal reaction rates occur at the regulated body temperature. However, recent data show that core body temperatures even of non-torpid endotherms fluctuate considerably. Additionally, peripheral temperatures can be considerably lower and more variable than core body temperatures. Here we discuss whether published data support the hypothesis that thermal performance curves of physiological reaction rates are plastic so that performance is maintained despite variable body temperatures within active (non-torpid) endotherms, and we explore mechanisms that confer plasticity. There is evidence that thermal performance curves in tissues that experience thermal fluctuations can be plastic, although this question remains relatively unexplored for endotherms. Mechanisms that alter thermal responses locally at the tissue level include transient potential receptor ion channels (TRPV and TRPM) and the AMP-activated protein kinase (AMPK) both of which can influence metabolism and energy expenditure. Additionally, the thermal sensitivity of processes that cause post-transcriptional RNA degradation can promote the relative expression of cold-responsive genes. Endotherms can respond to environmental fluctuations similarly to ectotherms, and thermal plasticity complements core body temperature regulation to increase whole-organism performance. Thermal plasticity is ancestral to endothermic thermoregulation, but it has not lost its selective advantage so that modern endotherms are a physiological composite of ancestral ectothermic and derived endothermic traits. PMID:28824463

  9. Short communication: Variation in the composition and properties of Swedish raw milk for ultra-high-temperature processing.

    Science.gov (United States)

    Karlsson, Maria A; Langton, Maud; Innings, Fredrik; Wikström, Malin; Lundh, Åse Sternesjö

    2017-04-01

    The composition and properties of raw milk are of great importance for the quality and shelf life of the final dairy product, especially in products with a long shelf life [e.g., ultra-high-temperature (UHT)-treated milk]. The objective of this study was to investigate the compositional variation in raw milk samples before processing at the dairy plant. Moreover, we wanted to investigate the effect of the UHT process on this variation (i.e., if the same variation could be observed in the corresponding UHT milk). The quality traits analyzed included detailed milk composition, counts of total and psychrotrophic bacteria, proteolytic activity, and color, as well as predictive measures of stability (i.e., ethanol stability and heat coagulating time). Samples of raw milk and the corresponding produced UHT milk were collected and analyzed on a monthly basis during 1 yr. Principal component analysis was used to identify months showing similarities and differences with respect to total variation. In contrast to previous studies, we observed only small variations between months and no clear effect of season for the raw milk. For the UHT milk, July and the winter months (December, January, and February) tended to separate from the other months. Quality traits showing significant variation were only to some extent identical in raw milk and UHT-processed milk. A better understanding of the natural variation in raw milk quality will provide opportunities to improve the shelf life of UHT-treated milk products. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Influence of reactions heats on variation of radius, temperature, pressure and chemical species amounts within a single acoustic cavitation bubble.

    Science.gov (United States)

    Kerboua, Kaouther; Hamdaoui, Oualid

    2018-03-01

    The scientific interest toward the study of acoustic bubble is mainly explained by its practical benefit in providing a reactional media favorable to the rapid evolution of chemical mechanism. The evolution of this mechanism is related to the simultaneous and dependent variation of the volume, temperature and pressure within the bubble, retrieved by the resolution of a differential equations system, including among others the thermal balance. This last one is subject to different assumptions, some authors deem simply that the temperature varies adiabatically during the collapsing phase, without considering the reactions heat of the studied mechanism. This paper aims to evaluate the pertinence of neglecting reactions heats in the thermal balance, by analyzing their effect on the variation of radius, temperature, pressure and chemical species amounts. The results show that the introduction of reactions heats conducts to a decrease of the temperature, an increase of the pressure and a reduction of the bubble volume. As a consequence, this leads to a drop of the quantities of free radicals produced by the chemical mechanism evolving within the bubble. This paper also proved that the impact of the consideration of reactions heats is dependent of the frequency and the acoustic amplitude of the ultrasonic wave. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, feeding and activity in rats.

    Science.gov (United States)

    Kamerman, Peter; Mitchell, Duncan; Laburn, Helen

    2002-02-01

    We have investigated whether there is circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, physical activity and feeding. We used nocturnally active Sprague-Dawley rats, housed at approximately 24 degrees C with a 12:12 h light:dark cycle (lights on 07:00 hours) and provided with food and water ad libitum. Nitric oxide synthesis was inhibited by intraperitoneal injection of the unspecific nitric oxide synthase inhibitor N-nitro- L-arginine methyl ester ( L-NAME, 100, 50, 25, 10 mg/kg), or the relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (100, 50 mg/kg), during the day ( approximately 09:00 hours) or night ( approximately 21:00 hours). Body temperature and physical activity were measured using radiotelemetry, while food intake was calculated by weighing each animal's food before as well as 12 and 24 h after each injection. We found that daytime injection of L-NAME and aminoguanidine had no effect on daytime body temperature. However, daytime injection of both drugs did decrease nocturnal food intake ( Pfood intake ( P<0.05) in a dose-dependent manner, but night-time injection of aminoguanidine inhibited only night-time activity ( P<0.05). The effects of nitric oxide synthase inhibition on body temperature, feeding and activity therefore are primarily a consequence of inhibiting constitutively expressed nitric oxide synthase, and are subject to circadian variation.

  12. Gene expression profile of Campylobacter jejuni in response to growth temperature variation.

    Science.gov (United States)

    Stintzi, Alain

    2003-03-01

    The foodborne pathogen Campylobacter jejuni is the primary causative agent of gastroenteritis in humans. In the present study a whole genome microarray of C. jejuni was constructed and validated. These DNA microarrays were used to measure changes in transcription levels over time, as C. jejuni cells responded to a temperature increase from 37 to 42 degrees C. Approximately 20% of the C. jejuni genes were significantly up- or downregulated over a 50-min period after the temperature increase. The global change in C. jejuni transcriptome was found to be essentially transient, with only a small subset of genes still differentially expressed after 50 min. A substantial number of genes with a downregulated coexpression pattern were found to encode for ribosomal proteins. This suggests a short growth arrest upon temperature stress, allowing the bacteria to reshuffle their energy toward survival and adaptation to the new growth temperature. Genes encoding chaperones, chaperonins, and heat shock proteins displayed the most dramatic and rapid upregulation immediately after the temperature change. Interestingly, genes encoding proteins involved in membrane structure modification were differentially expressed, either up- or downregulated, suggesting a different protein membrane makeup at the two different growth temperatures. Overall, these data provide new insights into the primary response of C. jejuni to surmount a sudden temperature upshift, allowing the bacterium to survive and adapt its transcriptome to a new steady state.

  13. DETERMINING THE COMPOSITION OF HIGH TEMPERATURE COMBUSTION PRODUCTS OF FOSSIL FUEL BASED ON VARIATIONAL PRINCIPLES AND GEOMETRIC PROGRAMMING

    Directory of Open Access Journals (Sweden)

    Velibor V Vujović

    2011-01-01

    Full Text Available This paper presents the algorithm and results of a computer program for calculation of complex equilibrium composition for the high temperature fossil fuel combustion products. The method of determining the composition of high temperatures combustion products at the temperatures appearing in the open cycle MHD power generation is given. The determination of combustion product composition is based on minimization of the Gibbs free energy. The number of equations to be solved is reduced by using variational principles and a method of geometric programming and is equal to the sum of the numbers of elements and phases. A short description of the computer program for the calculation of the composition and an example of the results are also given.

  14. Finite line-source model for borehole heat exchangers. Effect of vertical temperature variations

    Energy Technology Data Exchange (ETDEWEB)

    Bandos, Tatyana V.; Fernandez, Esther; Santander, Juan Luis G.; Isidro, Jose Maria; Perez, Jezabel; Cordoba, Pedro J. Fernandez de [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Montero, Alvaro; Urchueguia, Javier F. [Instituto de Ingenieria Energetica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2009-06-15

    A solution to the three-dimensional finite line-source (FLS) model for borehole heat exchangers (BHEs) that takes into account the prevailing geothermal gradient and allows arbitrary ground surface temperature changes is presented. Analytical expressions for the average ground temperature are derived by integrating the exact solution over the line-source depth. A self-consistent procedure to evaluate the in situ thermal response test (TRT) data is outlined. The effective thermal conductivity and the effective borehole thermal resistance can be determined by fitting the TRT data to the time-series expansion obtained for the average temperature. (author)

  15. Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M.

    Directory of Open Access Journals (Sweden)

    Ulrich Lutz

    2015-10-01

    Full Text Available Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae.

  16. Effects of temperature and resource variation on insect population dynamics: the bordered plant bug as a case study

    Science.gov (United States)

    Johnson, Christopher A.; Coutinho, Renato M.; Berlin, Erin; Dolphin, Kimberly E.; Heyer, Johanna; Kim, Britney; Leung, Alice; Sabellon, Jamie Lou; Amarasekare, Priyanga

    2017-01-01

    Summary In species with complex life cycles, population dynamics result from a combination of intrinsic cycles arising from delays in the operation of negative density-dependent processes (e.g., intraspecific competition) and extrinsic fluctuations arising from seasonal variation in the abiotic environment. Abiotic variation can affect species directly through their life history traits and indirectly by modulating the species’ interactions with resources or natural enemies.We investigate how the interplay between density-dependent dynamics and abiotic variability affects population dynamics of the bordered plant bug (Largus californicus), a Hemipteran herbivore inhabiting the California coastal sage scrub community. Field data show a striking pattern in abundance: adults are extremely abundant or nearly absent during certain periods of the year, leading us to predict that seasonal forcing plays a role in driving observed dynamics.We develop a stage-structured population model with variable developmental delays, in which fecundity is affected by both intra-specific competition and temporal variation in resource availability and all life history traits (reproduction, development, mortality) are temperature-dependent. We parameterize the model with experimental data on temperature-responses of life history and competitive traits and validate the model with independent field census data.We find that intra-specific competition is strongest at temperatures optimal for reproduction, which theory predicts leads to more complex population dynamics. Our model predicts that while temperature or resource variability interact with development-induced delays in self-limitation to generate population fluctuations, it is the interplay between all three factors that drive the observed dynamics. Considering how multiple abiotic factors interact with density-dependent processes is important both for understanding how species persist in variable environments and predicting species

  17. Annual variations and effects of temperature on Legionella spp. and other potential opportunistic pathogens in a bathroom.

    Science.gov (United States)

    Lu, Jingrang; Buse, Helen; Struewing, Ian; Zhao, Amy; Lytle, Darren; Ashbolt, Nicholas

    2017-01-01

    Opportunistic pathogens (OPs) in drinking water, like Legionella spp., mycobacteria, Pseudomonas aeruginosa, and free-living amobae (FLA) are a risk to human health, due to their post-treatment growth in water systems. To assess and manage these risks, it is necessary to understand their variations and environmental conditions for the water routinely used. We sampled premise tap (N cold = 26, N hot = 26) and shower (N shower = 26) waters in a bathroom and compared water temperatures to levels of OPs via qPCR and identified Legionella spp. by 16S ribosomal RNA (rRNA) gene sequencing. The overall occurrence and cell equivalent quantities (CE L-1) of Mycobacterium spp. were highest (100 %, 1.4 × 105), followed by Vermamoeba vermiformis (91 %, 493), Legionella spp. (59 %, 146), P. aeruginosa (14 %, 10), and Acanthamoeba spp. (5 %, 6). There were significant variations of OP's occurrence and quantities, and water temperatures were associated with their variations, especially for Mycobacterium spp., Legionella spp., and V. vermiformis. The peaks observed for Legionella, mainly consisted of Legionella pneumophila sg1 or Legionella anisa, occurred in the temperature ranged from 19 to 49 °C, while Mycobacterium spp. and V. vermiformis not only co-occurred with Legionella spp. but also trended to increase with increasing temperatures. There were higher densities of Mycobacterium in first than second draw water samples, indicating their release from faucet/showerhead biofilm. Legionella spp. were mostly at detectable levels and mainly consisted of L. pneumophila, L. anisa, Legionella donaldsonii, Legionella tunisiensis, and an unknown drinking water isolate based on sequence analysis. Results from this study suggested potential health risks caused by opportunistic pathogens when exposed to warm shower water with low chlorine residue and the use of Mycobacterium spp. as an indicator of premise pipe biofilm and the control management of those potential

  18. Microbial Community Response to Seasonal Temperature Variation in a Small-Scale Anaerobic Digester

    OpenAIRE

    Richard J. Ciotola; Jay F. Martin; Juan M. Castańo; Jiyoung Lee; Frederick Michel

    2013-01-01

    The Bacterial and Archaeal communities in a 1.14 m 3 ambient temperature anaerobic digester treating dairy cow manure were investigated using terminal restriction fragment length polymorphisms (T-RFLP) and direct sequencing of the cloned polymerase chain reaction (PCR) products. Results indicate shifts in the structure of the both the Archaeal and Bacterial communities coincided with digester re-inoculation as well as temperature and loading rate changes. Following re-inoculation of the sour ...

  19. Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees.

    Science.gov (United States)

    Vlam, Mart; Baker, Patrick J; Bunyavejchewin, Sarayudh; Zuidema, Pieter A

    2014-04-01

    Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming.

  20. Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

    Directory of Open Access Journals (Sweden)

    L. M. Dupont

    2011-11-01

    Full Text Available Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome for the last glacial as well as for other glacial periods of the past 300 Ka.

  1. Control of nanoparticle agglomeration through variation of the time-temperature profile in chemical vapor synthesis

    Science.gov (United States)

    Djenadic, Ruzica; Winterer, Markus

    2017-02-01

    The influence of the time-temperature history on the characteristics of nanoparticles such as size, degree of agglomeration, or crystallinity is investigated for chemical vapor synthesis (CVS). A simple reaction-coagulation-sintering model is used to describe the CVS process, and the results of the model are compared to experimental data. Nanocrystalline titania is used as model material. Titania nanoparticles are generated from titanium-tetraisopropoxide (TTIP) in a hot-wall reactor. Pure anatase particles and mixtures of anatase, rutile (up to 11 vol.%), and brookite (up to 29 vol.%) with primary particle sizes from 1.7 nm to 10.5 nm and agglomerate particle sizes from 24.3 nm to 55.6 nm are formed depending on the particle time-temperature history. An inductively heated furnace with variable inductor geometry is used as a novel system to control the time-temperature profile in the reactor externally covering a large wall temperature range from 873 K to 2023 K. An appropriate choice of inductor geometry, i.e. time-temperature profile, can significantly reduce the degree of agglomeration. Other particle characteristics such as crystallinity are also substantially influenced by the time-temperature profile.

  2. Control of nanoparticle agglomeration through variation of the time-temperature profile in chemical vapor synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Djenadic, Ruzica; Winterer, Markus, E-mail: markus.winterer@uni-due.de [Universität Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and CENIDE (Germany)

    2017-02-15

    The influence of the time-temperature history on the characteristics of nanoparticles such as size, degree of agglomeration, or crystallinity is investigated for chemical vapor synthesis (CVS). A simple reaction-coagulation-sintering model is used to describe the CVS process, and the results of the model are compared to experimental data. Nanocrystalline titania is used as model material. Titania nanoparticles are generated from titanium-tetraisopropoxide (TTIP) in a hot-wall reactor. Pure anatase particles and mixtures of anatase, rutile (up to 11 vol.%), and brookite (up to 29 vol.%) with primary particle sizes from 1.7 nm to 10.5 nm and agglomerate particle sizes from 24.3 nm to 55.6 nm are formed depending on the particle time-temperature history. An inductively heated furnace with variable inductor geometry is used as a novel system to control the time-temperature profile in the reactor externally covering a large wall temperature range from 873 K to 2023 K. An appropriate choice of inductor geometry, i.e. time-temperature profile, can significantly reduce the degree of agglomeration. Other particle characteristics such as crystallinity are also substantially influenced by the time-temperature profile.

  3. Spatial and temporal variation in the association between temperature and salmonellosis in NZ.

    Science.gov (United States)

    Lal, Aparna; Hales, Simon; Kirk, Martyn; Baker, Michael G; French, Nigel P

    2016-04-01

    Modelling the relationship between weather, climate and infectious diseases can help identify high-risk periods and provide understanding of the determinants of longer-term trends. We provide a detailed examination of the non-linear and delayed association between temperature and salmonellosis in three New Zealand cities (Auckland, Wellington and Christchurch). Salmonella notifications were geocoded to the city of residence for the reported case. City-specific associations between weekly maximum temperature and the onset date for reported salmonella infections (1997-2007) were modelled using non-linear distributed lag models, while controlling for season and long-term trends. Relatively high temperatures were positively associated with infection risk in Auckland (n=3,073) and Christchurch (n=880), although the former showed evidence of a more immediate relationship with exposure to high temperatures. There was no significant association between temperature and salmonellosis risk in Wellington. Projected increases in temperature with climate change may have localised health impacts, suggesting that preventative measures will need to be region-specific. This evidence contributes to the increasing concern over the public health impacts of climate change. © 2015 Public Health Association of Australia.

  4. Effect of Temperature Variation on Bond Characteristics between CFRP and Steel Plate

    Directory of Open Access Journals (Sweden)

    Shan Li

    2016-01-01

    Full Text Available In recent years, application of carbon fiber reinforced polymer (CFRP composite materials in the strengthening of existing reinforced concrete structures has gained widespread attention, but the retrofitting of metallic buildings and bridges with CFRP is still in its early stages. In real life, these structures are possibly subjected to dry and hot climate. Therefore, it is necessary to understand the bond behavior between CFRP and steel at different temperatures. To examine the bond between CFRP and steel under hot climate, a total of twenty-one double strap joints divided into 7 groups were tested to failure at constant temperatures from 27°C to 120°C in this paper. The results showed that the joint failure mode changed from debonding along between steel and adhesive interface failure to debonding along between CFRP and adhesive interface failure as the temperature increased beyond the glass transition temperature (Tg of the adhesive. The load carrying capacity decreased significantly at temperatures approaching or exceeding Tg. The interfacial fracture energy showed a similar degradation trend. Analytical models of the ultimate bearing capacity, interfacial fracture energy, and bond-slip relationship of CFRP-steel interface at elevated temperatures were presented.

  5. Application of the singular spectrum analysis technique to study the recent hiatus on the global surface temperature record.

    Science.gov (United States)

    Macias, Diego; Stips, Adolf; Garcia-Gorriz, Elisa

    2014-01-01

    Global surface temperature has been increasing since the beginning of the 20th century but with a highly variable warming rate, and the alternation of rapid warming periods with 'hiatus' decades is a constant throughout the series. The superimposition of a secular warming trend with natural multidecadal variability is the most accepted explanation for such a pattern. Since the start of the 21st century, the surface global mean temperature has not risen at the same rate as the top-of-atmosphere radiative energy input or greenhouse gas emissions, provoking scientific and social interest in determining the causes of this apparent discrepancy. Multidecadal natural variability is the most commonly proposed cause for the present hiatus period. Here, we analyze the HadCRUT4 surface temperature database with spectral techniques to separate a multidecadal oscillation (MDV) from a secular trend (ST). Both signals combined account for nearly 88% of the total variability of the temperature series showing the main acceleration/deceleration periods already described elsewhere. Three stalling periods with very little warming could be found within the series, from 1878 to 1907, from 1945 to 1969 and from 2001 to the end of the series, all of them coincided with a cooling phase of the MDV. Henceforth, MDV seems to be the main cause of the different hiatus periods shown by the global surface temperature records. However, and contrary to the two previous events, during the current hiatus period, the ST shows a strong fluctuation on the warming rate, with a large acceleration (0.0085°C year(-1) to 0.017°C year(-1)) during 1992-2001 and a sharp deceleration (0.017°C year(-1) to 0.003°C year(-1)) from 2002 onwards. This is the first time in the observational record that the ST shows such variability, so determining the causes and consequences of this change of behavior needs to be addressed by the scientific community.

  6. Analysing the Cenozoic depositional record

    DEFF Research Database (Denmark)

    Goledowski, Bartosz; Clausen, O.R.; Nielsen, S.B.

    2008-01-01

    between the global climate record (oxygen isotopes) and lithology variations on the Eocene-Oligocene transition in the eastern North Sea. Due to the strongly limited time resolution of low temperature thermochronology, the Cenozoic sedimentary record potentially provides the most detailed history...... models. The matrix mass deposition history will be compared with the paleoclimate record (e.g. oxygen isotope curves) to see if the previously observed correlation in the eastern North Sea can be extended to other ages and locations.  ...

  7. Validation of a Climate-Data Record of the "Clear-Kky" Surface Temperature of the Greenland Ice Sheet

    Science.gov (United States)

    Hall, Dorothy K.; Box, Jason E.; Koenig, Lora S.; DiGirolamo, Nicolo E.; Comiso, Josefino C.; Shuman, Christopher A.

    2011-01-01

    Surface temperatures on the Greenland Ice Sheet have been studied on the ground, using automatic weather station (AWS) data from the Greenland-Climate Network (GC-Net), and from analysis of satellite sensor data. Using Advanced Very High Frequency Radiometer (AVHRR) weekly surface temperature maps, warming of the surface of the Greenland Ice Sheet has been documented since 1981. We extended and refined this record using higher-resolution Moderate-Resolution Imaging Spectroradiometer (MODIS) data from March 2000 to the present. We developed a daily and monthly climate-data record (CDR) of the "clear-sky" surface temperature of the Greenland Ice Sheet using an ice-surface temperature (1ST) algorithm developed for use with MODIS data. Validation of this CDR is ongoing. MODIS Terra swath data are projected onto a polar stereographic grid at 6.25-km resolution to develop binary, gridded daily and mean-monthly 1ST maps. Each monthly map also has a color-coded image map that is available to download. Also included with the monthly maps is an accompanying map showing number of days in the month that were used to calculate the mean-monthly 1ST. This is important because no 1ST decision is made by the algorithm for cells that are considered cloudy by the internal cloud mask, so a sufficient number of days must be available to produce a mean 1ST for each grid cell. Validation of the CDR consists of several facets: 1) comparisons between ISTs and in-situ measurements; 2) comparisons between ISTs and AWS data; and 3) comparisons of ISTs with surface temperatures derived from other satellite instruments such as the Thermal Emission and Reflection Radiometer (ASTER) and Enhanced Thematic Mapper Plus (ETM+). Previous work shows that Terra MODIS ISTs are about 3 C lower than in-situ temperatures measured at Summit Camp, during the winter of 2008-09 under clear skies. In this work we begin to compare surface temperatures derived from AWS data with ISTs from the MODIS CDR. The

  8. Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

    Directory of Open Access Journals (Sweden)

    P. Bohleber

    2018-01-01

    Full Text Available Among ice core drilling sites in the European Alps, Colle Gnifetti (CG is the only non-temperate glacier to offer climate records dating back at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighbouring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+ trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures. We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a Little Ice Age cold period as well as a medieval climate anomaly. Part of the medieval climate period around AD 1100–1200 clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.

  9. Seasonal variation in the biocontrol efficiency of bacterial wilt is driven by temperature-mediated changes in bacterial competitive interactions.

    Science.gov (United States)

    Wei, Zhong; Huang, Jianfeng; Yang, Tianjie; Jousset, Alexandre; Xu, Yangchun; Shen, Qirong; Friman, Ville-Petri

    2017-10-01

    Microbe-based biocontrol applications hold the potential to become an efficient way to control plant pathogen disease outbreaks in the future. However, their efficiency is still very variable, which could be due to their sensitivity to the abiotic environmental conditions.Here, we assessed how environmental temperature variation correlates with ability of Ralstonia pickettii , an endophytic bacterial biocontrol agent, to suppress the Ralstonia solanacearum pathogen during different tomato crop seasons in China.We found that suppression of the pathogen was highest when the seasonal mean temperatures were around 20 °C and rapidly decreased with increasing mean crop season temperatures. Interestingly, low levels of disease incidence did not correlate with low pathogen or high biocontrol agent absolute densities. Instead, the biocontrol to pathogen density ratio was a more important predictor of disease incidence levels between different crop seasons. To understand this mechanistically, we measured the growth and strength of competition between the biocontrol agent and the pathogen over a naturally occurring temperature gradient in vitro . We found that the biocontrol strain grew relatively faster at low temperature ranges, and the pathogen at high temperature ranges, and that similar to field experiments, pathogen suppression peaked at 20 °C.Together, our results suggest that temperature-mediated changes in the strength of bacterial competition could potentially explain the variable R. solanacearum biocontrol outcomes between different crop seasons in China. Synthesis and applications . Our results suggest that abiotic environmental conditions, such as temperature, can affect the efficacy of biocontrol applications. Thus, in order to develop more consistent biocontrol applications in the future, we might need to find and isolate bacterial strains that can retain their functionality regardless of the changing environmental conditions.

  10. Oak tree ring stable isotope records of late-summer and autumn temperature changes in the Eastern European lowlands

    Science.gov (United States)

    Nagavciuc, Viorica; Persoiu, Aurel; McCarroll, Danny; Loader, Neil J.; Popa, Ionel

    2017-04-01

    Stable isotopes in tree rings are arguably the best proxies of past climate variability on annual time scales. They can be calibrated against instrumental data and used to extend climate reconstructions for centuries and even millennia. Although records with similar resolution and longer time spans have been recovered in different parts of the world - ice cores in Greenland and varved sediments in lakes in Northern and Western Europe - no such archives exist in Eastern Europe. Therefore, the isotopic composition of tree rings may be the only long-term and high resolution proxy available from this region. Here we present the first results of oxygen and carbon stable isotopes analyses of Quercus robur tree rings, covering the 1900-2016 period. The samples were collected at a low altitude (200m), site in NW Romania (Nușfalău, 47.198277 N, 22.668441 E). We have studied these data in connection with the oxygen isotopic composition of precipitation and the main climatic parameters to evaluate their potential for paleoclimatic reconstructions. Oxygen and carbon stable isotopes composition from earlywood and latewood were analysed separately, from nine pooled Quercus robur trees, using a high-temperature pyrolysis system (Flash HT) coupled to an isotope ratio mass spectrometer (Thermo Delta V), after whole-ring samples were prepared to alpha-cellulose by the modified Jayme-Wise method, and measured tree ring width for the same cores, using LINTAB equipment and TSAP software, with a precision of 0.01mm. Also, we analysed oxygen isotopic composition at Baia Mare station (BM), located at 85km distance from Nușfalău. Climate-measurement parameters relationships were analysed using daily (0.5°x0.5° ROCADA) and monthly (0.5°x0.5° CRU) climatic gridded database. The oxygen isotopic composition of precipitation at BM (average for the 2012-2015 period) has a seasonal variation, with maximum in July (-5.6‰) and minimum in December (-12.8‰). The mean stable isotope

  11. Little Ice Age versus Present Day: Comparison of Temperature, Precipitation and Seasonality in Speleothem Records from the Han-sur-Lesse Cave, Belgium.

    Science.gov (United States)

    Vansteenberge, S.; Van Opdenbosch, J.; Van Rampelbergh, M.; Verheyden, S.; Keppens, E.; Cheng, H.; Edwards, R. L.; Claeys, P. F.

    2015-12-01

    The Proserpine stalagmite is a 2 m large, tabular-shaped speleothem located in the Han-sur-Lesse cave in Belgium. The speleothem formed over the last 1000 years and is still growing. High-accuracy U/Th datings have indicated exceptionally high growth-rates of up to 2 mm per year. This, together with a well expressed annual layering, makes the Proserpine stalagmite an ideal candidate for high-resolution paleoclimate reconstructions of the last millennium. Previous work, including over 10 years of cave monitoring, has already learned us how short-term, i.e. decadal to seasonal, climate variations are incorporated within speleothem calcite from the Han-sur-Lesse cave system. It has been shown that δ18O and δ13C stable isotopes and trace element proxies of recently formed calcite reflect seasonal variations in temperature and precipitation of the near-cave environment (Verheyden et al, 2008; Van Rampelbergh et al., 2014). Now, this knowledge was used to infer local climate parameters further back in time to the period of +/- 1620-1630 CE, corresponding to one of the cold peaks within the Little Ice Age. Speleothem calcite was sampled at sub-annual resolution, with approximately 11 samples per year, for stable isotope analysis. LA-ICP-MS and µXRF analyses resulted in time series of trace elements. Preliminary results indicate a well expressed seasonal signal in δ13C and trace element composition but a multi-annual to decadal trend in δ18O. This combined proxy study eventually enables comparison of the expression of seasonality and longer term climate variations between a Little Ice Age cold peak and Present Day. References: Verheyden, S. et al., 2008, Monitoring climatological, hydrological and geochemical parameters in the Père Noël cave (Belgium): implication for the interpretation of speleothem isotopic and geochemical time-series. International Journal of Speleology, 37(3), 221-234. Van Rampelbergh, M. et al., 2014, Seasonal variations recorded in cave

  12. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Directory of Open Access Journals (Sweden)

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  13. Diffusion Filters for Variational Data Assimilation of Sea Surface Temperature in an Intermediate Climate Model

    Science.gov (United States)

    2015-01-01

    state estimation and forecast in real applica- tions using general circulation models (GCMs). In addition, other spatial multiscale variational analysis...Journal of Geophysical Research C: Oceans, vol. 102, no. 3, pp. 5655–5667, 1997. [15] P. C. Chu, W. Guihua, and Y. Chen, “Japan Sea thermohaline ...structure and circulation . Part III: autocorrelation functions,” Journal of Physical Oceanography, vol. 32, no. 12, pp. 3596–3615, 2002. [16] K.-A. Park and J

  14. Microbial Community Response to Seasonal Temperature Variation in a Small-Scale Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    Frederick Michel

    2013-10-01

    Full Text Available The Bacterial and Archaeal communities in a 1.14 m3 ambient temperature anaerobic digester treating dairy cow manure were investigated using terminal restriction fragment length polymorphisms (T-RFLP and direct sequencing of the cloned polymerase chain reaction (PCR products. Results indicate shifts in the structure of the both the Archaeal and Bacterial communities coincided with digester re-inoculation as well as temperature and loading rate changes. Following re-inoculation of the sour digester, the predominant Archaea shifted from Methanobrevibacter to Methanosarcina, which was the most abundant Archaea in the inoculum. Methonosarcina was replaced by Methanosaeta after the resumption of digester loading in the summer of 2010. Methanosaeta began to decline in abundance as the digester temperature cooled in the fall of 2010 while Methanobrevibacter increased in abundance. The microbial community rate of change was variable during the study period, with the most rapid changes occurring after re-inoculation.

  15. Bio-heat transfer model of electroconvulsive therapy: Effect of biological properties on induced temperature variation.

    Science.gov (United States)

    de Oliveira, Marilia M; Wen, Paul; Ahfock, Tony

    2016-08-01

    A realistic human head model consisting of six tissue layers was modelled to investigate the behavior of temperature profile and magnitude when applying electroconvulsive therapy stimulation and different biological properties. The thermo-electrical model was constructed with the use of bio-heat transfer equation and Laplace equation. Three different electrode montages were analyzed as well as the influence of blood perfusion, metabolic heat and electric and thermal conductivity in the scalp. Also, the effect of including the fat layer was investigated. The results showed that temperature increase is inversely proportional to electrical and thermal conductivity increase. Furthermore, the inclusion of blood perfusion slightly drops the peak temperature. Finally, the inclusion of fat is highly recommended in order to acquire more realistic results from the thermo-electrical models.

  16. The investigation of spatiotemporal variations of land surface temperature based on land use changes using NDVI in southwest of Iran

    Science.gov (United States)

    Fathizad, Hassan; Tazeh, Mahdi; Kalantari, Saeideh; Shojaei, Saeed

    2017-10-01

    Land use changes can bring about changes in land surface temperature (LST) which is influenced by climatic conditions and physical characteristics of the land surface. In this study, spatiotemporal variations of land surface temperature have been investigated in the desert area of Dasht-e-Abbas, Ilam, based on a variety of land use changes. The investigated periods for the study include 1990, 2000 and 2010 using Landsat image data. First, in mapping land use we used the Fuzzy ARTMAP Neural Network Classification method followed by determination of the NDVI Index to estimate land surface temperature. The results show an increase in LST in areas where degradation, land use and land cover changes have occurred. In 1990, 2000 and 2010, the average land surface temperature of the Fair Rangelands was 26.72 °C, 30.06 °C and 30.95 °C, respectively. This rangeland has been reduced by about 5%. For poor rangelands, the average LSTs were 26.95, 32.83 and 34.49 Cº, respectively which had a 18% reduction. In 1990, 2000 and 2010, the average land surface temperatures of agricultural lands were 24.31 °C, 27.87 °C and 28.61 °C, respectively which has been an increasing trend. The reason can be attributed to changes in cropping patterns of the study area.

  17. Validation of a Climate-Data Record of the "Clear-Sky" Surface Temperature of the Greenland Ice Sheet

    Science.gov (United States)

    Hall, Dorothy K.; Box, Jason E.; Koenig, Lora S.; DiGirolamo, Nicolo E.; Comiso, Josefino C.; Shuman, Christopher A.

    2011-01-01

    Surface temperatures on the Greenland Ice Sheet have been studied on the ground, using automatic weather station (AWS) data from the Greenland-Climate Network (GC-Net), and from analysis of satellite sensor data. Using Advanced Very High Frequency Radiometer (AVHRR) weekly surface temperature maps, warming of the surface of the Greenland Ice Sheet has been documented since 1981. We extended and refined this record using higher-resolution Moderate-Resolution Imaging Spectroradiometer (MODIS) data from March 2000 to the present. We developed a daily and monthly climate-data record (CDR) of the "clear-sky" surface temperature of the Greenland Ice Sheet using an ice-surface temperature (1ST) algorithm developed for use with MODIS data. Validation of this CDR is ongoing. MODIS Terra swath data are projected onto a polar stereographic grid at 6.25-km resolution to develop binary, gridded daily and mean-monthly 1ST maps. Each monthly map also has a color-coded image map that is available to download. Also included with the monthly maps is an accompanying map showing number of days in the month that were used to calculate the mean-monthly 1ST. This is important because no 1ST decision is made by the algorithm for cells that are considered cloudy by the internal cloud mask, so a sufficient number of days must be available to produce a mean 1ST for each grid cell. Validation of the CDR consists of several facets: 1) comparisons between ISTs and in-situ measurements; 2) comparisons between ISTs and AWS data; and 3) comparisons of ISTs with surface temperatures derived from other satellite instruments such as the Thermal Emission and Reflection Radiometer (ASTER) and Enhanced Thematic Mapper Plus (ETM+). Previous work shows that Terra MODIS ISTs are about 3 C lower than in-situ temperatures measured at Summit Camp, during the winter of 2008-09 under clear skies. In this work we begin to compare surface temperatures derived from AWS data with ISTs from the MODIS CDR.

  18. Temperature variation of higher-order elastic constants of MgO

    Indian Academy of Sciences (India)

    An effort has been made for obtaining higher-order elastic constants for MgO starting from basic parameters, viz. nearest-neighbor distance and hardness parameter using Coulomb and Börn–Mayer potentials. These are calculated in a wide temperature range (100–1000 K) and compared with available theoretical and ...

  19. Variation of low temperature internal friction of microplastic deformation of high purity molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pal-Val, P.P. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur); Kaufmann, H.J. (Akademie der Wissenschaften der DDR, Berlin)

    1984-08-01

    Amplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle or dislocation oscillations, respectively, dislocation point defect interactions as well as defect generation at microplastic deformation.

  20. Spatial and temporal variation of water temperature regimes on the Snoqualmie River network

    Science.gov (United States)

    Ashley E. Steel; Colin Sowder; Erin E. Peterson

    2016-01-01

    Although mean temperatures change annually and are highly correlated with elevation, the entire thermal regime on the Snoqualmie River, Washington, USA does not simply shift with elevation or season. Particular facets of the thermal regime have unique spatial patterns on the river network and at particular times of the year. We used a spatially and temporally dense...

  1. Effects of Temperature variations on the Super Fine Powderization of Korean Cultivated Wild Ginseng

    Directory of Open Access Journals (Sweden)

    Jin Ho Kim

    2006-12-01

    Full Text Available Objectives : The aim of this study was to find optimal conditions for producing red ginseng from cultivated wild ginseng using the Turbo Mill. Methods : Characteristics of powdered cultivated wild ginseng based on various temperature settings of the Turbo Mill were observed, and changes in the content was measured by HPLC for various ginsenosides. Results : 1. The diameter of cultivated wild ginseng powder ground by the Turbo Mill was around 10㎛. 2. As the temperature rose, presusre, Specific Mechanical Energy(SME, and density decreased, whileas Water Solubility Index(WSI increased. 3. As the temperature rose, super fine powder showed tendency to turn into dark brown. 4. Measuring content changes by HPLC, there was no detection of ginsenoside Rg3 and ginsenosideRg1, Rb1, and Rh2 concentrations decreased with increase in temperature. Conclusions : Super fine powder of cultivated wild ginseng produced by the Turbo Mill promotes easy absorption of effective ingredients by breaking the cell walls. Using this mechanism to produce red ginseng from cultivated wild ginseng, it yielded less than satisfactory results under the current experiment setup. Furtherresearches are needed to verify more suitable condition for the production of red ginseng.

  2. Genotypic Variation in the Response to Suboptimal Temperature at Different Plant Densities in Cut Chrysanthemum

    NARCIS (Netherlands)

    Ploeg, van der A.; Carvalho, S.M.P.; Heuvelink, E.

    2009-01-01

    Energy efficiency of greenhouse cut chrysanthemum (Chrysanthemum morifolium Ramat.) may be increased by breeding. In addition to breeding for cultivars with a shorter reaction time at suboptimal temperatures, an alternative approach would be to develop cultivars that are heavier at suboptimal

  3. Endogenous and exogenous components in the circadian variation of core body temperature in humans

    NARCIS (Netherlands)

    Hiddinga, AE; Beersma, DGM; VandenHoofdakker, RH

    Core body temperature is predominantly modulated by endogenous and exogenous components. In the present study we tested whether these two components can be reliably assessed in a protocol which lasts for only 120 h. In this so-called forced desynchrony protocol, 12 healthy male subjects (age 23.7

  4. Field tests reveal genetic variation for performance atlow temperatures in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Overgaard, Johannes; Sørensen, Jesper Givskov; Jensen, Louise Toft

    2010-01-01

    investigated a population of Drosophila melanogaster for performance at low temperature conditions in the field using release recapture assays and in the laboratory using standard cold resistance assays. The aim of the study was to get a better understanding of the nature and underlying mechanisms of the trait...

  5. Habitat related variation in UV tolerance of tropical marine red macrophytes is not temperature dependent

    NARCIS (Netherlands)

    van de Poll, W.H.; Bischof, K.; Buma, A.G.J.; Breeman, Arno

    Because tropical marine macrophytes experience high ultraviolet-B radiation (UVBR: 280-320 nm) it is assumed that they have high UV tolerance. This was investigated by examining the relative UV sensitivity of five Caribbean red macrophytes. Furthermore, the possibility of temperature dependence of

  6. Malaria morbidity and temperature variation in a low risk Kenyan district: a case of overdiagnosis?

    Science.gov (United States)

    Njuguna, John; Muita, James; Mundia, George

    2009-05-01

    Diagnosis of malaria using only clinical means leads to overdiagnosis. This has implications due to safety concerns and the recent introduction of more expensive drugs. Temperature is a major climatic factor influencing the transmission dynamics of malaria. This study looked at trends in malaria morbidity in the low risk Kenyan district of Nyandarua, coupled with data on temperature and precipitation for the years 2003-2006. July had the highest number of cases (12.2% of all cases) followed by August (10.2% of all cases). July and August also had the lowest mean maximum temperatures, 20.1 and 20.2 °C respectively. April, July and August had the highest rainfall, with daily means of 4.0, 4.3 and 4.9 mm, respectively. Observation showed that the coldest months experienced the highest number of cases of malaria. Despite the high rainfall, transmission of malaria tends to be limited by low temperatures due to the long duration required for sporogony, with fewer vectors surviving. These cold months also tend to have the highest number of cases of respiratory infections. There is a possibility that some of these were misdiagnosed as malaria based on the fact that only a small proportion of malaria cases were diagnosed using microscopy or rapid diagnostic tests. We conclude that overdiagnosis may be prevalent in this district and there may be a need to design an intervention to minimise it.

  7. Contrasting early Holocene temperature variations between monsoonal East Asia and westerly dominated Central Asia

    Science.gov (United States)

    Zhao, Jiaju; An, Chen-Bang; Huang, Yongsong; Morrill, Carrie; Chen, Fa-Hu

    2017-12-01

    Numerous studies have demonstrated that there are major differences in the timing of maximum Holocene precipitation between the monsoonal East Asia and westerly dominated Central Asia, but it is unclear if the moisture differences are also associated with corresponding temperature contrasts. Here we present the first alkenone-based paleotemperature reconstructions for the past 21 kyr from Lake Balikun, central Asia. We show, unlike the initiation of Holocene warm conditions at ∼11 kyr BP in the monsoon regions, the arid central Asia remained in a glacial-like cold condition prior to 8 kyr BP and experienced abrupt warming of ∼9 °C after the collapse of the Laurentide ice sheet. Comparison with pollen and other geochemical data indicates the abrupt warming is closely associated with major increase in the moisture supply to the region. Together, our multiproxy data indicate ∼2 thousand years delay of temperature and moisture optimum relative to local summer insolation maximum, suggesting major influence of the Laurentide ice sheet and other high latitude ice sheet forcings on the regional atmospheric circulation. In addition, our data reveal a temperature drop by ∼4 °C around 4 kyr BP lasting multiple centuries, coinciding with severe increases in aridity previously reported based on multiproxy data. In contrast, model simulations display a much less pronounced delay in the initiation of Holocene warm conditions, raising unresolved questions about the relative importance of local radiative forcing and high-latitude ice on temperature in this region.

  8. Temperature optimization of an electric heater by emissivity variation of heating elements

    Directory of Open Access Journals (Sweden)

    Cédric Hemmer

    2014-11-01

    Full Text Available This note addresses an industrial application concerning the way to optimize the surface temperature of commercial electrical heater. The aim of this paper is to reduce the temperature on accessible surfaces and electrical heater in order to respect the European standards and quality criteria imposed by the manufacturer. This target must be achieved by changing only the emissivity distribution of the electric heater components. A numerical study of the natural convection flow coupled with radiation is carried out in a heated room with an electric heater. The physical model includes the transport equations of mass, momentum, energy and radiative transfer which are solved numerically. Thermo-physical properties of the fluid are assumed to be dependent of the temperature. The numerical simulations are carried out for a two-dimensional, steady and turbulent flow using the finite volume approach. Results showed the influence of emissivity distribution of the electric heater components. The reducing of the heating foil emissivity allowed to decrease the radiative contribution on the foil and its temperature.

  9. Variations in water temperature and implications for trout populations in the Upper Schoharie Creek and West Kill, New York, USA

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.; Smith, Martyn J.; Mckeown, Donald M; Faulringer, Jason

    2016-01-01

    Water temperature is a key component of aquatic ecosystems because it plays a pivotal role in determining the suitability of stream and river habitat to most freshwater fish species. Continuous temperature loggers and airborne thermal infrared (TIR) remote sensing were used to assess temporal and spatial temperature patterns on the Upper Schoharie Creek and West Kill in the Catskill Mountains, New York, USA. Specific objectives were to characterize (1) contemporary thermal conditions, (2) temporal and spatial variations in stressful water temperatures, and (3) the availability of thermal refuges. In-stream loggers collected data from October 2010 to October 2012 and showed summer water temperatures exceeded the 1-day and 7-day thermal tolerance limits for trout survival at five of the seven study sites during both summers. Results of the 7 August 2012 TIR indicated there was little thermal refuge at the time of the flight. About 690,170 m2 of water surface area were mapped on the Upper Schoharie, yet only 0.009% (59 m2) was more than 1.0 °C below the median water surface temperature (BMT) at the thalweg and no areas were more than 2.0 °C BMT. On the West Kill, 79,098 m2 were mapped and 0.085% (67 m2) and 0.018% (14 m2) were BMT by 1 and 2 °C, respectively. These results indicate that summer temperatures in the majority of the study area are stressful for trout and may adversely affect growth and survival. Validation studies are needed to confirm the expectation that resident trout are in poor condition or absent from the downstream portion of the study area during warm-water periods.

  10. Creation of Single Chain of Nanoscale Skyrmion Bubbles with Record-high Temperature Stability in a Geometrically Confined Nanostripe

    KAUST Repository

    Hou, Zhipeng

    2018-01-04

    Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confined Fe3Sn2 nanostripe with a width comparable to the featured size of a skyrmion bubble. Systematic investigations on the thermal stability have revealed that the single chain of skyrmion bubbles can keep stable at temperatures varying from RT up to a record-high temperature of 630 K. This extreme stability can be ascribed to the weak temperature-dependent magnetic anisotropy and the formation of edge states at the boundaries of the nanostripes. The realization of the highly stable skyrmion bubble chain in a geometrically confined nanostructure is a very important step toward the application of skyrmion-based spintronic devices.

  11. Creation of Single Chain of Nanoscale Skyrmion Bubbles with Record-High Temperature Stability in a Geometrically Confined Nanostripe.

    Science.gov (United States)

    Hou, Zhipeng; Zhang, Qiang; Xu, Guizhou; Gong, Chen; Ding, Bei; Wang, Yue; Li, Hang; Liu, Enke; Xu, Feng; Zhang, Hongwei; Yao, Yuan; Wu, Guangheng; Zhang, Xi-Xiang; Wang, Wenhong

    2018-02-14

    Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confined Fe 3 Sn 2 nanostripe with a width comparable to the featured size of a skyrmion bubble. Systematic investigations on the thermal stability have revealed that the single chain of skyrmion bubbles can keep stable at temperatures varying from RT up to a record-high temperature of 630 K. This extreme stability can be ascribed to the weak temperature-dependent magnetic anisotropy and the formation of edge states at the boundaries of the nanostripes. The realization of the highly stable skyrmion bubble chain in a geometrically confined nanostructure is a very important step toward the application of skyrmion-based spintronic devices.

  12. Paleolimnological records of recent changes in glacier status, precipitation, and temperature in the Rwenzori Mountains, Uganda-D. R. Congo

    Science.gov (United States)

    Russell, J. M.; Eggermont, H. R.; Loomis, S.; Verschuren, D.

    2008-12-01

    Understanding the climatic controls on the status of tropical glaciers is vitally important to assessing past and present global climate change and the future stability of tropical alpine glaciers and ecosystems. Lack of high-resolution, independent reconstructions of trends in tropical temperatures, precipitation, and glacier extent severely limits our ability to decipher the causes of past glacier fluctuations. Here we investigate recent (the last ca. 1,000 years) changes in sedimentation and climate using lakes in the Rwenzori Mountains, Uganda-D. R. Congo. Clastic mineral input to 5 lakes situated downstream from Rwenzori glaciers is high and stable for much of the past millennium, but declines rapidly from 1870 AD toward the present. In contrast, 11 Rwenzori lakes without glaciers in their catchment show little to no such change. We therefore interpret the decline in clastic mineral input to reflect the retreat of Rwenzori glaciers from expanded positions reached during the 'Little Ice Age' (LIA). Comparison of this glacier history to organic geochemical records of temperature and hydrology from regional lakes indicates that the Rwenzori glaciers expanded during a cool yet dry LIA, and retreated during the relatively warm, moist conditions of the past century. Rising temperature thus played an important, if not dominant role in the retreat of the Rwenzori's glaciers from their LIA positions. perhaps due to the effects of air temperature on the phase (rain vs. snow) of precipitation falling on alpine glaciers.

  13. Microclimatic temperatures of Danish cattle farms: a better understanding of the variation in transmission potential of Schmallenberg virus

    DEFF Research Database (Denmark)

    Haider, Najmul; Cuellar, Ana Carolina; Kjær, Lene Jung

    farms and also a spatial pattern with a strong geographical trend suggesting that disease transmission may vary substantially between regions even in a small country like Denmark – and this could be useful for designing risk based surveillance for emerging and reemerging vector-borne diseases......., Falster, and southern Zealand. Conclusion: Microclimatic temperature is highly important for understanding and predicting insect-borne virus transmission on Danish cattle farms. We were able to predict the daily farm level EIP of Schmallenberg virus for 17 years. We found large variation in EIP between...

  14. Monitoring And Recording Data For Solar Radiation Temperature And Charging Current

    Directory of Open Access Journals (Sweden)

    Aung Bhone Myint

    2015-08-01

    Full Text Available A data logger based on 8051 microcontroller has been implemented in this project to measure the solar radiation temperature and charging current. Development of a low-cost data logger can easily be made and easily be used to convert the analog signal of physical parameters of various test or other purposes of engineering. By using a suitable program code it can be used to read the value digitally with a PC. Our aim is to provide with a module and a software package when installed in a computer one can remotely acquire and monitor several numbers of the same or different types of signals sequentially at a time. Signals obtained from various sensors have been effectively conditioned. Now interfacing these signals using ADC with the Bluetooth module port of a computer satisfies the very goal of data acquisition. Proposed system provides better performance and has low cost versatile portable.

  15. Comment on Boretti (2013), `Statistical analysis of the temperature records for the Northern Territory of Australia'

    Science.gov (United States)

    Trewin, Blair C.; Jones, David A.

    2015-04-01

    Boretti (Theor Appl Clim 114:567-573, 2013) presents an analysis of observed temperature trends in the Northern Territory, Australia, and claims that this analysis is inconsistent with trends reported by the Australian Bureau of Meteorology and thus that the Bureau of Meteorology results are flawed. This paper presents evidence that the results presented by Boretti (2013) are at least partly attributable to his failure to account for inhomogeneities in the underlying station data and to the use of time periods for trends which are different to those in the Bureau of Meteorology analyses with which he is comparing them. The evidence, as presented in this paper, therefore fails to support his conclusions of inconsistencies between the Bureau of Meteorology analyses and the station data.

  16. Data on records of indoor temperature and relative humidity in a University building

    Directory of Open Access Journals (Sweden)

    O. Irulegi

    2017-08-01

    Full Text Available Good indoor comfort and air quality are essential for correct educational development. Most reports in this field focus on primary and secondary school buildings, with numerous projects conducted in the Mediterranean Zone. However, little has been done in the context of university buildings. Data on indoor temperature and relative humidity data acquired trough field surveys of a seminar room located in the Architecture Faculty in San Sebastian (Spain is provided in this paper. The seminar room was monitored during a typical spring week. The data presented in the article are related to the research article entitled Retrofit strategies towards Net Zero Energy Educational Buildings: a case study at the University of the Basque Country (Ref. 0378–7788.

  17. Deep-focus earthquake analogs recorded at high pressure and temperature in the laboratory.

    Science.gov (United States)

    Schubnel, Alexandre; Brunet, Fabrice; Hilairet, Nadège; Gasc, Julien; Wang, Yanbin; Green, Harry W

    2013-09-20

    Phase transformations of metastable olivine might trigger deep-focus earthquakes (400 to 700 kilometers) in cold subducting lithosphere. To explore the feasibility of this mechanism, we performed laboratory deformation experiments on germanium olivine (Mg2GeO4) under differential stress at high pressure (P = 2 to 5 gigapascals) and within a narrow temperature range (T = 1000 to 1250 kelvin). We found that fractures nucleate at the onset of the olivine-to-spinel transition. These fractures propagate dynamically (at a nonnegligible fraction of the shear wave velocity) so that intense acoustic emissions are generated. Similar to deep-focus earthquakes, these acoustic emissions arise from pure shear sources and obey the Gutenberg-Richter law without following Omori's law. Microstructural observations prove that dynamic weakening likely involves superplasticity of the nanocrystalline spinel reaction product at seismic strain rates.

  18. Highly Nonlinear Temperature-Dependent Fin Analysis by Variational Iteration Method

    DEFF Research Database (Denmark)

    Fouladi, F.; Hosseinzadeh, E.; Barari, Amin

    2010-01-01

    In this research, the variational iteration method as an approximate analytical method is utilized to overcome some inherent limitations arising as uncontrollability to the nonzero endpoint boundary conditions and is used to solve some examples in the field of heat transfer. The available exact...... solutions for the linear equations and the numerical solutions for the nonlinear ones are good bases to demonstrate the accuracy and efficiency of the proposed method. With the help of the method one can simply analyze the thermal characteristics of a straight rectangular fin for all possible types of heat...

  19. Ground-based thermal mapping on Venus: temperature fields and variations of SO2 and HDO

    Science.gov (United States)

    Encrenaz, T.; Greathouse, T. K.; Widemann, T.; Bézard, B.; Fouchet, T.; Atreya, S. K.; Sagawa, H.

    2017-09-01

    As a continuation of our ground-based thermal imaging campaign of Venus, we have been mapping Venus in December 2016 and January 2017 to monitor the behaviour of SO2 and H2O (through its proxy HDO). The SO2 mixing ratio was at its maximum since 2012. As during our previous runs, short-term variations of SO2 (with a timescale of a few hours) were observed. There is still no evidence for a correlation or an anti-correlation between SO2 and HDO. The thermal maps might show some correlation with the topography, but this remains to be confirmed with further observations.

  20. Seasonal variation in blood and muscle oxygen stores attributed to diving behavior, environmental temperature and pregnancy in a marine predator, the California sea lion.

    Science.gov (United States)

    Villegas-Amtmann, Stella; Atkinson, Shannon; Paras-Garcia, Alberto; Costa, Daniel P

    2012-08-01

    Survival depends on an animal's ability to find and acquire prey. In diving vertebrates, this ability is directly related to their physiological capability (e.g. oxygen stores). We studied the seasonal variation in oxygen stores, body temperature and body condition in California sea lions (Zalophus californianus) (CSL) as a function of seasonal variation in temperature, primary productivity, diving behavior and reproductive stage. During summer, blood oxygen stores were significantly greater and muscle oxygen stores were significantly lower than in winter. Total oxygen stores, body condition and body temperature did not change between seasons but variations in body temperature were greater during summer. Changes in oxygen stores are partly attributed to diving behavior, temperature and pregnancy that could increase oxygen consumption. Blood and muscle oxygen stores appear to be influenced by reproductive state. Blood oxygen stores are more likely influenced by diving behavior and temperature than muscle oxygen stores. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. A GIS Approach to Wind,SST(Sea Surface Temperature) and CHL(Chlorophyll) variations in the Caspian Sea

    Science.gov (United States)

    Mirkhalili, Seyedhamzeh

    2016-07-01

    Chlorophyll is an extremely important bio-molecule, critical in photosynthesis, which allows plants to absorb energy from light. At the base of the ocean food web are single-celled algae and other plant-like organisms known as Phytoplankton. Like plants on land, Phytoplankton use chlorophyll and other light-harvesting pigments to carry out photosynthesis. Where Phytoplankton grow depends on available sunlight, temperature, and nutrient levels. In this research a GIS Approach using ARCGIS software and QuikSCAT satellite data was applied to visualize WIND,SST(Sea Surface Temperature) and CHL(Chlorophyll) variations in the Caspian Sea.Results indicate that increase in chlorophyll concentration in coastal areas is primarily driven by terrestrial nutrients and does not imply that warmer SST will lead to an increase in chlorophyll concentration and consequently Phytoplankton abundance.

  2. Determining the Temperature Variation of the on the Wall of the Casting Mould during the casting of the Hadfield Steel

    Directory of Open Access Journals (Sweden)

    Constantin Marta

    2011-10-01

    Full Text Available The present paper approaches the analysis of the metal temperature variation during the filling and solidification of steel in the casting mould. Furthermore we made determinations upon the heat transfer through the wall of the casting mould. The casting temperature, the casting speed and the heat transfer through the walls of the mould have a remarkable impact upon the shrinkage process for the prevention of casting defects (heat cavities and cracks. These cavities are also development cores for the heat cracks and the concentration of strains, which reduce the chemical, physical and mechanical properties of the cast parts. The shrinkage cavities represent one of the main defects of the cast product, and their reduction should be made up to the limits of technical possibilities.

  3. Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

    DEFF Research Database (Denmark)

    Frankel, Mika; Bekö, Gabriel; Timm, Michael

    2012-01-01

    with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total...... inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor...... bacteria peaked in spring (median, 2,165 CFU/m3) and were lowest in summer (median, 240 CFU/m3). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass...

  4. Petrological and geochemical records of short-lived, high temperature metamorphism during exhumation of the Sulu UHP metamorphic terrane

    Science.gov (United States)

    Zong, K.; Liu, Y.; Zhang, X.; Ye, Y.; Gao, C.

    2010-12-01

    The Dabie-Sulu terrane of east-central China is the largest and most well known ultrahigh-pressure (UHP) metamorphic terrane in the world, which has become one of the most important places to study continental subduction-related UHP metamorphism. In the past two decades, numerous petrological, geochemical, petrophysical and tectonophysical studies were carried out in the Dabie-Sulu UHP metamorphic terrane. However, almost all of these studies have focused on UHP metamorphic processes, while only a few studies have focused on the thermal evolution. Here we present a detailed petrological and geochemical study on the southern Sulu UHP eclogites in order to constrain the “hot” exhumation of the Sulu UHP metamorphic terrane. Eclogite-hosted garnet-spinel-corundum-quartz-bearing titanohematite veins near the main hole of the Chinese Continental Scientific Drilling Project (CCSD-MH) are described for the first time in the Sulu UHP metamorphic terrane. A vein composed of titanohematite + ilmenite + hematite + spinel + garnet + corundum + quartz + K-feldspar + albite was studied in detail. The unusual mineral assemblage of garnet + spinel + corundum + quartz implies that this vein could have experienced high temperatures (>900 oC). Although within garnets showed well-defined Mg and Mn diffusion zoning in the rim as a result of the high temperature event, slight Mg and Mn growth zoning was preserved in the core. Thus, we suggest that the Sulu UHP terrane could have experienced a short-lived, high-temperature stage during exhumation. This is consistent with trace element zoning recorded by garnet, omphacite and apatite and much higher temperatures recorded by rutiles and zircons with ages of ~200 Ma in the CCSD-MH eclogites. We speculate that slab breakoff may have caused asthenospheric upwelling, which could have provided a heat pulse for the short-lived, high-temperature metamorphism in the Sulu UHP terrane. Such high temperature stage could have contributed to the

  5. Discontinuous variation of the surface plasmon linewidth of small sodium nanoparticles with electron temperatures

    Science.gov (United States)

    Wang, Guozhong; Zheng, Yizhuang; Zi, Jian

    2015-05-01

    We found a novel behavior of the surface plasmon linewidth of small sodium nanoparticles, which monotonically decreases with the electron temperature and bears a sudden drop or rise at high electron temperatures. Our calculation is based on the model constructed by splitting the total Hamiltonian of all valence electrons of a metallic nanoparticle into two sub-Hamiltonians and the coupling between them. This novel behavior of the surface plasma resonance linewidth can be verified by pump-probe femtosecond spectroscopy experiments and is able to take place for metallic particles with sizes less than few nanometers. In addition, we propose that it is the size uncertainty of small nanoparticles that yields the intrinsic linewidth of the surface plasmon resonance, which is supported by experimental and theoretical results of nanoparticles Na8 and Na20.

  6. Seasonal temperature variations influence tapetum mitosis patterns associated with reproductive fitness.

    Science.gov (United States)

    Lavania, Umesh C; Basu, Surochita; Kushwaha, Jyotsana Singh; Lavania, Seshu

    2014-09-01

    Environmental stress in plants impacts many biological processes, including male gametogenesis, and affects several cytological mechanisms that are strongly interrelated. To understand the likely impact of rising temperature on reproductive fitness in the climate change regime, a study of tapetal mitosis and its accompanying meiosis over seasons was made to elucidate the influence of temperature change on the cytological events occurring during microsporogenesis. For this we used two species of an environmentally sensitive plant system, i.e., genus Cymbopogon Sprengel (Poaceae), namely Cymbopogon nardus (L.) Rendle var. confertiflorus (Steud.) Bor (2n = 20) and Cymbopogon jwaruncusha (Jones) Schult. (2n = 20). Both species flower profusely during extreme summer (48 °C) and mild winter (15 °C) but support low and high seed fertility, respectively, in the two seasons. We have shown that tapetal mitotic patterns over seasons entail differential behavior for tapetal mitosis. During the process of tapetum development there are episodes of endomitosis that form either (i) an endopolyploid genomically imbalanced uninucleate and multinucleate tapetum, and (or) (ii) an acytokinetic multinucleate genomically balanced tapetum, with the progression of meiosis in the accompanying sporogenous tissue. The relative frequency of occurrence of the two types of tapetum mitosis patterns is significantly different in the two seasons, and it is found to be correlated with the temperature conditions. Whereas, the former (genomically imbalanced tapetum) are prevalent during the hot summer, the latter (genomically balanced tapetum) are frequent under optimal conditions. Such a differential behaviour in tapetal mitosis vis-à-vis temperature change is also correspondingly accompanied by substantial disturbances or regularity in meiotic anaphase disjunction. Both species show similar patterns. The study underpins that tapetal mitotic behaviour per se could be a reasonable indicator to

  7. Temperature variation induced by the pulsed-periodic laser pumping under terahertz wave generation

    Science.gov (United States)

    Kitaeva, G. Kh; Moiseenko, E. V.; Shepelev, A. V.

    2017-09-01

    During nonlinear-optical parametric frequency conversion the heat-related effects occur, considerably influencing the conversion process. We develop versatile methods for analytic and numerical calculations of thermo-optical parameters and the temperature distribution inside a non-linear crystal pumped by periodic laser pulses. As an example, numerical results are presented for a number of laser-based schemes actual for the non-linear optical terahertz wave generation and parametric frequency conversion processes.

  8. STUDY REGARDING THE CAR BRAKE DISC TEMPERATURE VARIATION DURING THE LENGTHY BRAKING

    OpenAIRE

    DRAGOMIR George; PANCU Rares; MITRAN Tudor Adrian; GEORGESCU Liviu; MOCA Sorin; CHIOREANU Catalin

    2015-01-01

    When a car descends a slope with a great length, the thermal stresses resulting from contact between the brake discs and brake pads, there is possible to exceed the maximal limits of the materials resistance, resulting the rapid wear, decreasing performance of braking or the loss control of movement and the road accidents are producing. The study refers to establishment the dependence between the braking intensity and time when the temperature achieves a maximum limit ...

  9. STUDY REGARDING THE CAR BRAKE DISC TEMPERATURE VARIATION DURING THE LENGTHY BRAKING

    OpenAIRE

    DRAGOMIR George; PANCU Rares; MITRAN Tudor Adrian; GEORGESCU Liviu

    2015-01-01

    When a car descends a slope with a great length, the thermal stresses resulting from contact between the brake discs and brake pads, there is possible to exceed the maximal limits of the materials resistance, resulting the rapid wear, decreasing the performance of braking or the loss control of movement and the road accidents are producing. The study refers to establishment the dependence between the braking intensity and time when the temperature achieves a the maximu...

  10. An analysis on performance degradation of silicon photomultiplies over temperatures variation for PET-MR application

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyeong Jin; Kim, Hyoung Taek; Lim, Kyung Taek; Cho, Min Sik; Kim, Gi Yoon; Cho, Gyu Seong [Dept. of Nuclear and Quantum EngineeringKorea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-08-15

    A PET-MR system is particularly useful in diagnosing brain diseases. We have developed a prototype positron emission tomography (PET) system which can be inserted into the bore of a whole-body magnetic resonance imaging (MRI) system that enables us to obtain PET and MRI images simultaneously with a reduced cost. Silicon photomultipliers (SiPM) are appropriated as a PET detector at PET/MR system because detectors have a high gain and are insensitive to magnetic fields. Despite of its improved performance compared to that of PMT-based detectors, there is a problem of the photo-peak channel shift which is due to the increase of the temperature inside the ring detector. This problem will occur decreasing sensitivity of the PET and image distortion. In this paper, I quantitative analyze parameters of the KAIST SiPM depending on temperature by experiments. And I designed cooling methods in consideration of the degradation of sensors for correction of the temperature in the PET gantry. According to this research, we expect that distortive images and degradation of the sensitivity will not be occurred with using the above idea to reduce heat even if the PET system operates for a long time.

  11. Natural CMT2 variation is associated with genome-wide methylation changes and temperature seasonality.

    Directory of Open Access Journals (Sweden)

    Xia Shen

    2014-12-01

    Full Text Available As Arabidopsis thaliana has colonized a wide range of habitats across the world it is an attractive model for studying the genetic mechanisms underlying environmental adaptation. Here, we used public data from two collections of A. thaliana accessions to associate genetic variability at individual loci with differences in climates at the sampling sites. We use a novel method to screen the genome for plastic alleles that tolerate a broader climate range than the major allele. This approach reduces confounding with population structure and increases power compared to standard genome-wide association methods. Sixteen novel loci were found, including an association between Chromomethylase 2 (CMT2 and temperature seasonality where the genome-wide CHH methylation was different for the group of accessions carrying the plastic allele. Cmt2 mutants were shown to be more tolerant to heat-stress, suggesting genetic regulation of epigenetic modifications as a likely mechanism underlying natural adaptation to variable temperatures, potentially through differential allelic plasticity to temperature-stress.

  12. Weakening temperature control on the interannual variations of spring carbon uptake across northern lands

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Shilong [Chinese Academy of Sciences (CAS), Beijing (China); Peking Univ., Beijing (China); Liu, Zhuo [Peking Univ., Beijing (China); Wang, Tao [Chinese Academy of Sciences (CAS), Beijing (China); Peng, Shushi [Peking Univ., Beijing (China); Ciais, Philippe [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Huang, Mengtian [Peking Univ., Beijing (China); Ahlstrom, Anders [Stanford Univ., CA (United States); Burkhart, John F. [Univ. of Oslo (Norway); Chevallier, Frédéric [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Janssens, Ivan A. [Univ. of Antwerp, Wilrijk (Belgium); Jeong, Su-Jong [South Univ. of Science and Technology of China, Shenzhen (China); Lin, Xin [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Mao, Jiafu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, John [National Oceanic and Atmospheric Administration Earth Systems Research Lab., Boulder, CO (United States); Univ. of Colorado, Boulder, CO (United States); Mohammat, Anwar [Chinese Academy of Sciences (CAS), Beijing (China); Myneni, Ranga B. [Boston Univ., MA (United States); Peñuelas, Josep [Centre for Ecological Research and Forestry Applications (CREAF), Barcelona (Spain); Shi, Xiaoying [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stohl, Andreas [Norwegian Institute for Air Research (NILU), Kjeller (Norway); Yao, Yitong [Peking Univ., Beijing (China); Zhu, Zaichun [Peking Univ., Beijing (China); Tans, Pieter P. [National Oceanic and Atmospheric Administration Earth Systems Research Lab., Boulder, CO (United States)

    2017-04-24

    Ongoing spring warming allows the growing season to begin earlier, enhancing carbon uptake in northern ecosystems. We use 34 years of atmospheric CO2 concentration measurements at Barrow, Alaska (BRW, 71° N) to show that the interannual relationship between spring temperature and carbon uptake has recently shifted. Here, we use two indicators: the spring zero-crossing date of atmospheric CO2 (SZC) and the magnitude of CO2 drawdown between May and June (SCC). The previously reported strong correlation between SZC, SCC and spring land temperature (ST) was found in the first 17 years of measurements, but disappeared in the last 17 years. As a result, the sensitivity of both SZC and SCC to warming decreased. Simulations with an atmospheric transport model coupled to a terrestrial ecosystem model suggest that the weakened interannual correlation of SZC and SCC with ST in the last 17 years is attributable to the declining temperature response of spring net primary productivity (NPP) rather than to changes in heterotrophic respiration or in atmospheric transport patterns. Reduced chilling during dormancy and emerging light limitation are possible mechanisms that may have contributed to the loss of NPP response to ST. These results thus challenge the ‘warmer spring–bigger sink’ mechanism.

  13. Soil microbial responses to temporal variations of moisture and temperature in a chihuahuan desert grassland.

    Science.gov (United States)

    Bell, Colin; McIntyre, Nancy; Cox, Stephen; Tissue, David; Zak, John

    2008-07-01

    Global climate change models indicate that storm magnitudes will increase in many areas throughout southwest North America, which could result in up to a 25% increase in seasonal precipitation in the Big Bend region of the Chihuahuan Desert over the next 50 years. Seasonal precipitation is a key limiting factor regulating primary productivity, soil microbial activity, and ecosystem dynamics in arid and semiarid regions. As decomposers, soil microbial communities mediate critical ecosystem processes that ultimately affect the success of all trophic levels, and the activity of these microbial communities is primarily regulated by moisture availability. This research is focused on elucidating soil microbial responses to seasonal and yearly changes in soil moisture, temperature, and selected soil nutrient and edaphic properties in a Sotol Grassland in the Chihuahuan Desert at Big Bend National Park. Soil samples were collected over a 3-year period in March and September (2004-2006) at 0-15 cm soil depth from 12 3 x 3 m community plots. Bacterial and fungal carbon usage (quantified using Biolog 96-well micro-plates) was related to soil moisture patterns (ranging between 3.0 and 14%). In addition to soil moisture, the seasonal and yearly variability of soil bacterial activity was most closely associated with levels of soil organic matter, extractable NH(4)-N, and soil pH. Variability in fungal activity was related to soil temperatures ranging between 13 and 26 degrees C. These findings indicate that changes in soil moisture, coupled with soil temperatures and resource availability, drive the functioning of soil-microbial dynamics in these desert grasslands. Temporal patterns in microbial activity may reflect the differences in the ability of bacteria and fungi to respond to seasonal patterns of moisture and temperature. Bacteria were more able to respond to moisture pulses regardless of temperature, while fungi only responded to moisture pulses during cooler seasons with

  14. Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations

    Directory of Open Access Journals (Sweden)

    S. M. Khaykin

    2013-07-01

    Full Text Available Following recent studies evidencing the influence of deep convection on the chemical composition and thermal structure of the tropical lower stratosphere, we explore its impact on the temperature diurnal variation in the upper troposphere and lower stratosphere using the high-resolution COSMIC GPS radio-occultation temperature measurements spanning from 2006 through 2011. The temperature in the lowermost stratosphere over land during summer displays a marked diurnal cycle characterized by an afternoon cooling. This diurnal cycle is shown collocated with most intense land convective areas observed by the Tropical Rainfall Measurement Mission (TRMM precipitation radar and in phase with the maximum overshooting occurrence frequency in late afternoon. Two processes potentially responsible for that are identified: (i non-migrating tides, whose physical nature is internal gravity waves, and (ii local cross-tropopause mass transport of adiabatically cooled air by overshooting turrets. Although both processes can contribute, only the lofting of adiabatically cooled air is well captured by models, making it difficult to characterize the contribution of non-migrating tides. The impact of deep convection on the temperature diurnal cycle is found larger in the southern tropics, suggesting more vigorous convection over clean rain forest continents than desert areas and polluted continents in the northern tropics.

  15. Solar cycle variations of stratospheric ozone and temperature in simulations of a coupled chemistry-climate model

    Directory of Open Access Journals (Sweden)

    J. Austin

    2007-01-01

    Full Text Available The results from three 45-year simulations of a coupled chemistry climate model are analysed for solar cycle influences on ozone and temperature. The simulations include UV forcing at the top of the atmosphere, which includes a generic 27-day solar rotation effect as well as the observed monthly values of the solar fluxes. The results are analysed for the 27-day and 11-year cycles in temperature and ozone. In accordance with previous results, the 27-day cycle results are in good qualitative agreement with observations, particularly for ozone. However, the results show significant variations, typically a factor of two or more in sensitivity to solar flux, depending on the solar cycle. In the lower and middle stratosphere we show good agreement also between the modelled and observed 11-year cycle results for the ozone vertical profile averaged over low latitudes. In particular, the minimum in solar response near 20 hPa is well simulated. In comparison, experiments of the model with fixed solar phase (solar maximum/solar mean and climatological sea surface temperatures lead to a poorer simulation of the solar response in the ozone vertical profile, indicating the need for variable phase simulations in solar sensitivity experiments. The role of sea surface temperatures and tropical upwelling in simulating the ozone minimum response are also discussed.

  16. Mg/Ca and Mn/Ca ratios in benthic foraminifera: the potential to reconstruct past variations in temperature and hypoxia in shelf regions

    Directory of Open Access Journals (Sweden)

    J. Groeneveld

    2013-07-01

    showed significantly increased Mn/Ca, being highest when bottom water dissolved oxygen was at a minimum. Our study suggests that trace metal/Ca ratios in benthic foraminifera from shelf regions have the potential to record past variations in bottom water temperature and dissolved oxygen concentrations, but an additional impact of the inorganic carbonate chemistry cannot be excluded.

  17. Combined Effects Of Stress Work And Heat Generation On MHD Natural Convection Flow Along A Vertical Flat Plate With Power Law Variation Of Uniform Surface Temperature

    National Research Council Canada - National Science Library

    Mohammad Mahfuzul Islam; Md. M. Alam; M. M. Parvez; M. A. Rahman

    2015-01-01

    Abstract In this paper is presented to study conjugate effects of stress work and heat generation on MHD natural convection flow along a vertical flat plate with power law variation of surface temperature...

  18. Decadally-resolved sea surface temperature and salinity records of the East Sea (Japan Sea) over the last 2000 years

    Science.gov (United States)

    Lee, K. E.; Park, W.; Rhee, T. S.

    2013-12-01

    The East Asia monsoon is an important component of Earth's climate system, yet its dynamical processes are not sufficiently understood. Previous studies indicate a strong coupling between monsoon circulation and northern hemisphere climate change on interannual to decadal time scales. However, our understanding of monsoon variability and teleconnections to high- and low-latitude mechanisms on longer time scale remains insufficient. In this study, decadally-resolved continuous sea surface temperature and salinity records over the last 2000 years from alkenone and planktonic foraminiferal oxygen isotope ratio analyses of East Sea (Japan Sea) marine sediments have been reconstructed to investigate East Asia monsoon variability. The results show that during the Medieval Climate Anomaly, East Asia was characterized by surface warming with a strengthened summer monsoon. Summer monsoon-related precipitation increased and pluvials possibly dominated in the region at that time. On the other hand, Asia monsoon failure and severe drought is characteristic of the Little Ice Age. Comparisons of the records with other paleoclimate records indicate a possible connection between changes in the mid-latitude East Asia monsoon, Arctic Oscillation (AO)/North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO) over the period.

  19. Record-low sintering-temperature (600 °C) of solid-oxide fuel cell electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Dasari, Hari Prasad, E-mail: energyhari@nitk.edu.in [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Chemical Engineering Department, National Institute of Technology Karnataka, Mangalore 575025, Karnataka (India); Ahn, Kiyong; Park, Sun-Young; Hong, Jongsup; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Kim, Byung-Kook; Lee, Hae-Weon [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Jong-Ho, E-mail: jongho@kist.re.kr [High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2016-07-05

    One of the major problems arising with Solid-Oxide Fuel Cell (SOFC) electrolyte is conventional sintering which requires a very high temperature (>1300 °C) to fully density the electrolyte material. In the present study, the sintering temperature of SOFC electrolyte is drastically decreased down to 600 °C. Combinational effects of particle size reduction, liquid-phase sintering mechanism and microwave sintering resulted in achieving full density in such a record-low sintering temperature. Gadolinium doped Ceria (GDC) nano-particles are synthesized by co-precipitation method, Lithium (Li), as an additional dopant, is used as liquid-phase sintering aid. Microwave sintering of this electrolyte material resulted in decreasing the sintering temperature to 600 °C. Micrographs obtained from Scanning/Transmission Electron Microscopy (SEM/TEM) clearly pointed a drastic growth in grain-size of Li-GDC sample (∼150 nm) than compared to GDC sample (<30 nm) showing the significance of Li addition. The sintered Li-GDC samples displayed an ionic conductivity of ∼1.00 × 10{sup −2} S cm{sup −1} at 600 °C in air and from the conductivity plots the activation energy is found to be 0.53 eV. - Highlights: • Sintering temperature is drastically decreased to 600 °C. • Key factors: Particle size reduction, liquid-phase and microwave sintering. • Nano-Li-GDC sample has ionic conductivity of ∼1.00 × 10{sup −2} S cm{sup −1} at 600 °C in air.

  20. Use and Limitations of a Climate-Quality Data Record to Study Temperature Trends on the Greenland Ice Sheet

    Science.gov (United States)

    Hall, Dorothy K.; Comiso, Josefino C.; Shuman, Christopher A.; Koenig, Lora S.; DiGirolamo, Nicolo E.

    2011-01-01

    Enhanced melting of the Greenland Ice Sheet has been documented in recent literature along with surface-temperature increases measured using infrared satellite data since 1981. Using a recently-developed climate-quality data record, 11- and 12-year trends in the clear-sky ice-surface temperature (IST) of the Greenland Ice Sheet have been studied using the Moderate-Resolution Imaging Spectroradiometer (MODIS) IST product. Daily and monthly MODIS ISTs of the Greenland Ice Sheet beginning on 1 March 2000 and continuing through 31 December 2010 are now available at 6.25-km spatial resolution on a polar stereographic grid as described in Hall et al. (submitted). This record will be elevated in status to a climate-data record (CDR) when more years of data become available either from the MODIS on the Terra or Aqua satellites, or from the Visible Infrared Imager Radiometer Suite (VIIRS) to be launched in October 2011. Maps showing the maximum extent of melt for the entire ice sheet and for the six major drainage basins have been developed from the MODIS IST dataset. Twelve-year trends of the duration of the melt season on the ice sheet vary in different drainage basins with some basins melting progressively earlier over the course of the study period. Some (but not all) of the basins also show a progressively-longer duration of melt. IST 12-year trends are compared with in-situ data, and climate data from the Modern Era Retrospective-Analysis for Research and Applications (MERRA) Reanalysis.

  1. Modelling tree ring cellulose δ18O variations in two temperature-sensitive tree species from North and South America

    Science.gov (United States)

    Lavergne, Aliénor; Gennaretti, Fabio; Risi, Camille; Daux, Valérie; Boucher, Etienne; Savard, Martine M.; Naulier, Maud; Villalba, Ricardo; Bégin, Christian; Guiot, Joël

    2017-11-01

    Oxygen isotopes in tree rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil-vegetation-atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

  2. Spectral, mineralogical, and geochemical variations across Home Plate, Gusev Crater, Mars indicate high and low temperature alteration

    Science.gov (United States)

    Schmidt, M.E.; Farrand, W. H.; Johnson, J. R.; Schroder, C.; Hurowitz, J.A.; McCoy, T.J.; Ruff, S.W.; Arvidson, R. E.; Des Marais, D.J.; Lewis, K.W.; Ming, D. W.; Squyres, S. W.; De Souza, P.A.

    2009-01-01

    Over the last ~ 3??years in Gusev Crater, Mars, the Spirit rover observed coherent variations in color, mineralogy, and geochemistry across Home Plate, an ~ 80??m-diameter outcrop of basaltic tephra. Observations of Home Plate from orbit and from the summit of Husband Hill reveal clear differences in visible/near-infrared (VNIR) colors between its eastern and western regions that are consistent with mineralogical compositions indicated by M??ssbauer spectrometer (MB) and by Miniature Thermal Emission Spectrometer (Mini-TES). Pyroxene and magnetite dominate the east side, while olivine, nanophase Fe oxide (npOx) and glass are more abundant on the western side. Alpha Particle X-Ray Spectrometer (APXS) observations reveal that eastern Home Plate has higher Si/Mg, Al, Zn, Ni, and K, while Cl and Br are higher in the west. We propose that these variations are the result of two distinct alteration regimes that may or may not be temporally related: a localized, higher temperature recrystallization and alteration of the east side of Home Plate and lower temperature alteration of the western side that produced npOx.

  3. Influence of Anatomical Detail and Tissue Conductivity Variations in Simulations of Multi-Contact Nerve Cuff Recordings.

    Science.gov (United States)

    Garai, Purbasha; Koh, Ryan G L; Schuettler, Martin; Stieglitz, Thomas; Zariffa, Jose

    2017-09-01

    Accurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters. To construct the model, in vivo recordings were obtained in a rat sciatic nerve using an 8-channel nerve cuff electrode, after which the nerve was imaged using magnetic resonance imaging (MRI). The FE model was constructed based on the MRI data, and included progressive branching of the fascicles. Neural pathways were defined in the model for the tibial, peroneal and sural fascicles. The locations of these pathways were selected so as to maximize the correlations between the simulated and in vivo recordings. The sensitivity analysis showed that varying the conductivities of neural tissues had little influence on the ability of the model to reproduce the recording patterns obtained experimentally. On the other hand, the increased anatomical detail did substantially alter the recording patterns observed, demonstrating that incorporating fascicular branching is an important consideration in models of nerve cuff recordings. The model used in this study constitutes an improved simulation tool and can be used in the design of neural interfaces.

  4. A five million year record of compositional variations in mantle sources to magmatism on Santiago, southern Cape Verde archipelago

    DEFF Research Database (Denmark)

    Barker, Abigail K.; Holm, Paul Martin; Peate, David W.

    2010-01-01

    High-precision Pb isotope data and Sr-Nd-Hf isotope data are presented together with major and trace element data for samples spanning the 4.6 Ma history of volcanism at Santiago, in the southern Cape Verde islands. Pb isotope data confirm the positive ¿8/4 signature of the southern islands....... The temporal variations in 208Pb/204Pb reflect minor lateral variations in Th/U of this recycled ocean crust package entering the melting zone beneath the islands. The location of the EM1-like component is more equivocal. A shallow lithospheric location is possible, but this would require a coincidence between...... spatial compositional variations in the lithosphere (EM1 is spatially restricted to the southern islands) and flow lines in the upwelling mantle revealed by seismic anisotropy. Therefore, we favour a deeper asthenospheric mantle source for the EM1-like source...

  5. Estuarine Alkenones: A High-Resolution Record of Sea-Surface Temperature from Narragansett Bay over the Past Millennia

    Science.gov (United States)

    Salacup, J.; Farmer, J. R.; Herbert, T.; Prell, W. L.

    2009-12-01

    Here we present a Uk’37 sea-surface temperature (SST) reconstruction from Narragansett Bay, RI. We analyzed sediments from three geographically separated cores for Uk’37, the concentration of C37 alkenones (C37-total), widely accepted as a paleo-productivity proxy, and elemental carbon and nitrogen concentrations. Our age model suggests our archives cover at least the past 600 years with a sampling resolution of 6-8 years. In contrast to alkenone profiles reported from the much lower salinity Chesapeake Bay, the alkenone fingerprint in Narragansett Bay lacks significant contributions from the C37:4 ketone and is consistent with production by open-ocean haptophytes (in all likelihood, E. huxleyi). Comparison of the results from each of the three cores yields temperature offsets consistent with instrumental SST gradients within Narragansett Bay suggesting sedimentary alkenones were produced locally, rather than being produced in, and advected from, the nearby Atlantic Ocean. Absolute SSTs vary by up to 1°C on decadal timescales and by up to 3.5°C over the entire record. On centennial timescales, SSTs increase by ~0.5°C between ~1450 and 1600 before declining by 1-1.5°C between 1600 and the mid-1800s perhaps recording the local expression of the Little Ice Age. Productivity, inferred from C37-total, is steady throughout the Bay from ~1450 to ~1725. However, after 1725 concentrations increase in the upper Bay but not in the lower, suggesting changes in land-use and runoff may have influenced alkenone production. Sedimentary alkenones, synthesized by a limited number of coccolithophorids, are the basis of the Uk’37 SST proxy, traditionally employed in climate reconstructions from open-ocean sediments. This work suggests that alkenones preserved in shallow-water sediments, like those of Narragansett Bay, may provide a new opportunity for reconstructing estuarine and coastal temperatures in other muddy high-deposition-rate settings.

  6. A New Global Empirical Model of the Electron Temperature with the Inclusion of the Solar Activity Variations for IRI

    Science.gov (United States)

    Truhlik, V.; Triskova, L.

    2012-01-01

    A data-base of electron temperature (T(sub e)) comprising of most of the available LEO satellite measurements in the altitude range from 350 to 2000 km has been used for the development of a new global empirical model of T(sub e) for the International Reference Ionosphere (IRI). For the first time this will include variations with solar activity. Variations at five fixed altitude ranges centered at 350, 550, 850, 1400, and 2000 km and three seasons (summer, winter, and equinox) were represented by a system of associated Legendre polynomials (up to the 8th order) in terms of magnetic local time and the earlier introduced in vdip latitude. The solar activity variations of T(sub e) are represented by a correction term of the T(sub e) global pattern and it has been derived from the empirical latitudinal profiles of T(sub e) for day and night (Truhlik et al., 2009a). Comparisons of the new T(sub e) model with data and with the IRI 2007 Te model show that the new model agrees well with the data generally within standard deviation limits and that the model performs better than the current IRI T(sub e) model.

  7. Metabolic fingerprinting of gilthead seabream (Sparus aurata liver to track interactions between dietary factors and seasonal temperature variations

    Directory of Open Access Journals (Sweden)

    Tomé S. Silva

    2014-08-01

    Full Text Available Farmed gilthead seabream is sometimes affected by a metabolic syndrome, known as the “winter disease”, which has a significant economic impact in the Mediterranean region. It is caused, among other factors, by the thermal variations that occur during colder months and there are signs that an improved nutritional status can mitigate the effects of this thermal stress. For this reason, a trial was undertaken where we assessed the effect of two different diets on gilthead seabream physiology and nutritional state, through metabolic fingerprinting of hepatic tissue. For this trial, four groups of 25 adult gilthead seabream were reared for 8 months, being fed either with a control diet (CTRL, low-cost commercial formulation or with a diet called “Winter Feed” (WF, high-cost improved formulation. Fish were sampled at two time-points (at the end of winter and at the end of spring, with liver tissue being taken for FT-IR spectroscopy. Results have shown that seasonal temperature variations constitute a metabolic challenge for gilthead seabream, with hepatic carbohydrate stores being consumed over the course of the inter-sampling period. Regarding the WF diet, results point towards a positive effect in terms of performance and improved nutritional status. This diet seems to have a mitigating effect on the deleterious impact of thermal shifts, confirming the hypothesis that nutritional factors can affect the capacity of gilthead seabream to cope with seasonal thermal variations and possibly contribute to prevent the onset of “winter disease”.

  8. Elevational variation in body-temperature response to immune challenge in a lizard

    Directory of Open Access Journals (Sweden)

    Francisco Javier Zamora-Camacho

    2016-04-01

    Full Text Available Immunocompetence benefits animal fitness by combating pathogens, but also entails some costs. One of its main components is fever, which in ectotherms involves two main types of costs: energy expenditure and predation risk. Whenever those costs of fever outweigh its benefits, ectotherms are expected not to develop fever, or even to show hypothermia, reducing costs of thermoregulation and diverting the energy saved to other components of the immune system. Environmental thermal quality, and therefore the thermoregulation cost/benefit balance, varies geographically. Hence, we hypothesize that, in alpine habitats, immune-challenged ectotherms should show no thermal response, given that (1 hypothermia would be very costly, as the temporal window for reproduction is extremely small, and (2 fever would have a prohibitive cost, as heat acquisition is limited in such habitat. However, in temperate habitats, immune-challenged ectotherms might show a febrile response, due to lower cost/benefit balance as a consequence of a more suitable thermal environment. We tested this hypothesis in Psammodromus algirus lizards from Sierra Nevada (SE Spain, by testing body temperature preferred by alpine and non-alpine lizards, before and after activating their immune system with a typical innocuous pyrogen. Surprisingly, non-alpine lizards responded to immune challenge by decreasing preferential body-temperature, presumably allowing them to save energy and reduce exposure to predators. On the contrary, as predicted, immune-challenged alpine lizards maintained their body-temperature preferences. These results match with increased costs of no thermoregulation with elevation, due to the reduced window of time for reproduction in alpine environment.

  9. Albedo, Land Cover, and Daytime Surface Temperature Variation Across an Urbanized Landscape

    Science.gov (United States)

    Trlica, A.; Hutyra, L. R.; Schaaf, C. L.; Erb, A.; Wang, J. A.

    2017-11-01

    Land surface albedo is a key parameter controlling the local energy budget, and altering the albedo of built surfaces has been proposed as a tool to mitigate high near-surface temperatures in the urban heat island. However, most research on albedo in urban landscapes has used coarse-resolution data, and few studies have attempted to relate albedo to other urban land cover characteristics. This study provides an empirical description of urban summertime albedo using 30 m remote sensing measurements in the metropolitan area around Boston, Massachusetts, relating albedo to metrics of impervious cover fraction, tree canopy coverage, population density, and land surface temperature (LST). At 30 m spatial resolution, median albedo over the study area (excluding open water) was 0.152 (0.112-0.187). Trends of lower albedo with increasing urbanization metrics and temperature emerged only after aggregating data to 500 m or the boundaries of individual towns, at which scale a -0.01 change in albedo was associated with a 29 (25-35)% decrease in canopy cover, a 27 (24-30)% increase in impervious cover, and an increase in population from 11 to 386 km-2. The most intensively urbanized towns in the region showed albedo up to 0.035 lower than the least urbanized towns, and mean mid-morning LST 12.6°C higher. Trends in albedo derived from 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) measurements were comparable, but indicated a strong contribution of open water at this coarser resolution. These results reveal linkages between albedo and urban land cover character, and offer empirical context for climate resilient planning and future landscape functional changes with urbanization.

  10. Degradation and persistence of rotenone in soils and influence of temperature variations.

    Science.gov (United States)

    Cavoski, Ivana; Caboni, Pierluigi; Sarais, Giorgia; Miano, Teodoro

    2008-09-10

    The persistence and degradation of rotenone and its primary degradation product 12a beta-hydroxyrotenone in soils were determined under standardized laboratory conditions in the dark at 20 or 10 degrees C and at 40% of water holding capacity. Degradation experiments were carried out on two types of soil collected in southern Italy, a silt clay loam (SCL) and a loamy soil (L). A kinetic model was developed to describe degradation rates of rotenone, taking into account the production, retention, and degradation of the main metabolites. The DT50 values of rotenone and 12a beta-hydroxyrotenone, were 8 and 52 days in SCL soil, and 5 and 23 days in L soil at 20 degrees C, respectively. However, at 10 degrees C a tendency for slower degradation of rotenone and 12a beta-hydroxyrotenone was observed (25 and 118 days in SCL and 21 and 35 days in L soils, respectively). The differences were significant for most data sets. Temperature had a strong effect on degradation; a 10 degrees C increase in temperature resulted in a decrease in the DT50 value by a factor of 3.1 and 2.2 in SCL and of 4.2 and 1.4 in L soils for both rotenone and 12a beta-hydroxyrotenone, respectively. Results show that the degradation rates of both rotenone and 12a beta-hydroxyrotenone were greatly affected by temperature changes and soil physicochemical properties. The degradation reaction fits the two compartment or the multiple compartment model pathways better, which clearly indicates a rather complex rotenone degradation process in soils. Results provide further insights on the rates and the mechanisms of rotenone degradation in soils, aiming to more clearly describe the degradation pathway of chemical residues in the environment.

  11. CFD Simulation of Temperature Variation in Carboniferous Rock Strata During UCG

    Directory of Open Access Journals (Sweden)

    Tomasz Janoszek

    2013-01-01

    Full Text Available The numerical simulation was based on the computational fluid dynamics formalism in order to identify the change of temperature in rock strata during underground coal gasification (UCG. The calculations simulated the coal gasification process using oxygen and water vapour as a gasification agent in 120 hours. Based on the selected software (Ansys-Fluent a model of underground coal gasification (UCG process was developed. The flow of the gasification agent, the description of the turbulence model, the heat-exchange model and the method of simulation of chemical reactions of gasification are presented herein.

  12. Spatial and temporal variations of electron temperatures and densities from EUV-emitting lithium plasmas.

    Science.gov (United States)

    Coons, R W; Harilal, S S; Polek, M; Hassanein, A

    2011-07-01

    Planar slabs of pure Li were irradiated with 1.064 nm, 6 ns Nd:YAG laser pulses. Determination of plasma densities at both the earliest times of plasma formation and near the target surface was performed using Nomarski interferometry. The plasma parameters at later times were evaluated using optical emission spectroscopy. The space- and time-dependent electron densities and temperatures of the plasma were determined from their Stark broadening and the relative intensities of the spectral lines, respectively. The advantages and disadvantages of both of these techniques are evaluated and discussed.

  13. Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat.

    Science.gov (United States)

    Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

    2016-08-01

    We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes) were significantly (0.5°C) higher in the evening than morning. Minute ventilation (V̇e) increased from 54.3 ± 7.9 and 54.9 ± 6.8 l/min at 10 min to 71.4 ± 8.1 and 76.5 ± 11.8 l/min at 48.5 min in the morning and evening, respectively (both P Time of day had no effect on V̇e (P = 0.44). When V̇e as the output response was plotted against Tes as thermal input, the Tes threshold for increases in V̇e was higher in the evening than morning (37.2 ± 0.7 vs. 36.6 ± 0.6°C, P = 0.009), indicating the ventilatory response to the same core temperature is smaller in the evening. In protocol 2, the circadian rhythm-related higher resting Tes seen in the evening was adjusted down to the same temperature seen in the morning by immersing the subject in cold water. Importantly, the time course of changes in V̇e during exercise were smaller in the evening, but the threshold for V̇e remained higher in the evening than morning (P time of day has no effect on time course hyperventilation during exercise in the heat, despite the higher core temperatures in the evening. This is likely due to diurnal variation in the control of ventilation in response to rising core temperature. Copyright © 2016 the American Physiological Society.

  14. Temperature variation in the 24 hours before the initial symptoms of stroke Variação da temperatura nas 24 horas anteriores aos sintomas iniciais do acidente vascular cerebral

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    Fernando Morgadinho Santos Coelho

    2010-04-01

    Full Text Available A few studies have performed to evaluate the temperature variation influences over on the stroke rates in Brazil. METHOD: 176 medical records of inpatients were analyzed after having had a stroke between 2004 and 2006 at Hospital Israelita Albert Einstein. The temperature preceding the occurrence of the symptoms was recorded, as well as the temperature 6, 12 and 24 hours before the symptoms in 6 different weather substations, closest to their houses in São Paulo. RESULTS: Strokes occurred more frequently after a variation of 3ºC between 6 and 24 hours before the symptoms. There were most hospitalizations between 23-24ºC. CONCLUSION: Incidence of stroke on these patients was increased after a variation of 3º Celsius within 24 hours before the ictus. The temperature variations could be an important factor in the occurrence of strokes in this population.Poucos trabalhos têm estudado a variação sazonal e de temperatura em acidente vascular cerebral (AVC no Brasil. MÉTODO: Foram analisados 176 registros de pacientes com AVC no Hospital Israelita Albert Einstein entre 2004 e 2006. Foram anotadas as temperaturas ambientes do início dos sintomas, bem como as temperaturas de 6, 12 e 24 horas antes dos sintomas, em 6 diferentes subestações metereológicas mais próximas da casa do paciente em São Paulo. RESULTADOS: Houve aumento da incidência do AVC com a variação de 3ºC entre 6 e 24 horas antes do início dos sintomas. Houve um pico de internação entre 23-24ºC. CONCLUSÃO: A variação de temperatura de 3ºC nas 24 horas que antecederam o início dos sintomas pode ter sido um fator importante na ocorrência do AVC.

  15. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    Directory of Open Access Journals (Sweden)

    W. Nijland

    2011-05-01

    Full Text Available Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

  16. The cryptoendolithic microbial environment in the Antarctic cold desert: temperature variations in nature

    Science.gov (United States)

    McKay, C. P.; Friedmann, E. I.

    1985-01-01

    In the Antarctic cold desert, cryptoendolithic microorganisms live under the surface of porous sandstone rocks. During the austral summer, the environment of the near-surface rock layers colonized by organisms is characterized by two kinds of temperature oscillations, both occurring across the freezing point. Low-frequency (diurnal) and large-amplitude (up to about 20 degrees C) oscillations on the sunlit surface of rocks result in a daily freeze-thaw cycle. This is a result of the diurnal changes in the sun altitude and angle with respect to the rock surface. The biological effect of this oscillation is the regulation of the onset and cessation of metabolic activity. The high-frequency (few minutes) oscillations occur only under certain weather conditions (sunny days with light winds) and are superimposed on the low-frequency oscillations. They are caused by the cooling effect of wind gusts on rock surfaces that are much warmer than ambient air temperatures. High-frequency oscillations result in a rapid freeze-thaw cycle on the surface, which, however, does not reach the microbial zone. These high-frequency freeze-thaw oscillations are probably the cause of the abiotic nature of the rock surface. Both oscillations seem to have an effect on rock weathering.

  17. The role of natural climatic variation in perturbing the observed global mean temperature trend

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, B.G. [CSIRO Marine and Atmospheric Research, Aspendale, VIC (Australia)

    2011-02-15

    Controversy continues to prevail concerning the reality of anthropogenically-induced climatic warming. One of the principal issues is the cause of the hiatus in the current global warming trend. There appears to be a widely held view that climatic change warming should exhibit an inexorable upwards trend, a view that implies there is no longer any input by climatic variability in the existing climatic system. The relative roles of climatic change and climatic variability are examined here using the same coupled global climatic model. For the former, the model is run using a specified CO{sub 2} growth scenario, while the latter consisted of a multi-millennial simulation where any climatic variability was attributable solely to internal processes within the climatic system. It is shown that internal climatic variability can produce global mean surface temperature anomalies of {+-}0.25 K and sustained positive and negative anomalies sufficient to account for the anomalous warming of the 1940s as well as the present hiatus in the observed global warming. The characteristics of the internally-induced negative temperature anomalies are such that if this internal natural variability is the cause of the observed hiatus, then a resumption of the observed global warming trend is to be expected within the next few years. (orig.)

  18. Solar Cycle Variation of Upper Thermospheric Temperature Over King Sejong Station, Antarctica

    Directory of Open Access Journals (Sweden)

    Jong-Kyun Chung

    2000-12-01

    Full Text Available A ground Fabry-Perot interferometer has been used to measure atomic oxygen nightglow (OI 630.0 nm from the thermosphere (about 250 km at King Sejong station (KSS, geographic: 62.22oS, 301.25oE; geomagnetic: 50.65oS, 7.51oE, Antarctica. While numerous studies of the thermosphere have been performed on high latitude using ground-based Fabry-Perot interferometers, the thermospheric measurements in the Southern Hemisphere are relatively new and sparse. Therefore, the nightglow measurements at KSS play an important role in extending the thermospheric studies to the Southern Hemisphere. In this study, we investigated the effects of the geomagnetic and solar activities on the thermospheric neutral temperatures that have been observed at KSS in 1989 and 1997. The measured average temperatures are 1400 K in 1989 and 800 K in 1997, reflecting the influence of the solar activity. The measurements were compared with empirical models, MSIS-86 and semi-empirical model, VSH.

  19. NOAA Climate Data Record (CDR) of GPS RO-Calibrated AMSU Channel 7 (Temperatures of Troposphere / Stratosphere, TTS), Version 1.0 (Version Superseded)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Climate Data Records (CDR) for Channel 7 contains Radio Occulation (RO) calibrated brightness temperatures from AMSU-A channel 7 measurements at 54.9 GHz from...

  20. Seawater Temperature and Salinity Moored Time-Series Records, Collected During 2010 and 2011 in Vieques Sound and Virgin Passage (NODC Accession 0088063)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea-Bird SBE37SM MicroCat Conductivity/Temperature (CT) recorders were deployed between March 2010 and April 2011 on shallow water moorings located in Vieques Sound,...

  1. CRED Subsurface Temperature Recorder (STR); NWHI, MID; Long: -177.36784, Lat: 28.27774 (WGS84); Sensor Depth: 0.30m; Data Range: 20020926-20030727.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  2. CRED Subsurface Temperature Recorder (STR); PRIA, HOW; Long: -176.62172, Lat: 00.80645 (WGS84); Sensor Depth: 18.89m; Data Range: 20060128-20080205.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  3. CRED Subsurface Temperature Recorder (STR); NWHI, LAY; Long: -171.73890, Lat: 25.77954 (WGS84); Sensor Depth: 1.21m; Data Range: 20040924-20060910.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  4. CRED Subsurface Temperature Recorder (STR); AMSM, ROS; Long: -168.16883, Lat: -14.54871 (WGS84); Sensor Depth: 31.40m; Data Range: 20080313-20100303.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  5. CRED Subsurface Temperature Recorder (STR); MHI, HAW; Long: -155.90161, Lat: 19.07380 (WGS84); Sensor Depth: 17.68m; Data Range: 20081101-20101011.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  6. CRED Subsurface Temperature Recorder (STR); PRIA, WAK; Long: 166.65107, Lat: 19.30617 (WGS84); Sensor Depth: 13.11m; Data Range: 20070505-20090323.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  7. CRED Subsurface Temperature Recorder (STR); MHI, OAH; Long: -158.13685, Lat: 21.35464 (WGS84); Sensor Depth: 17.98m; Data Range: 20080514-20090206.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  8. CRED Subsurface Temperature Recorder (STR); AMSM, OFU; Long: -169.62487, Lat: -14.16393 (WGS84); Sensor Depth: 6.40m; Data Range: 20040207-20050720.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  9. CRED Subsurface Temperature Recorder (STR); AMSM, TUT; Long: -170.56222, Lat: -14.28368 (WGS84); Sensor Depth: 8.23m; Data Range: 20050804-20060218.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  10. CRED Subsurface Temperature Recorder (STR); PRIA, JAR; Long: -160.00803, Lat: -00.36902 (WGS84); Sensor Depth: 6.40m; Data Range: 20040328-20060102.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  11. CRED Subsurface Temperature Recorder (STR); PRIA, KIN; Long: -162.38440, Lat: 06.38252 (WGS84); Sensor Depth: 6.40m; Data Range: 20060330-20080404.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  12. CRED Subsurface Temperature Recorder (STR); NWHI, PHR; Long: -175.88215, Lat: 27.78250 (WGS84); Sensor Depth: 12.50m; Data Range: 20060913-20060922.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  13. CRED Subsurface Temperature Recorder (STR); PRIA, JAR; Long: -159.99663, Lat: -00.38183 (WGS84); Sensor Depth: 9.80m; Data Range: 20040328-20060321.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  14. CRED Subsurface Temperature Recorder (STR); PRIA, WAK; Long: 166.62868, Lat: 19.28032 (WGS84); Sensor Depth: 12.19m; Data Range: 20070505-20090324.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  15. CRED Subsurface Temperature Recorder (STR); NWHI, KUR; Long: -178.36842, Lat: 28.42927 (WGS84); Sensor Depth: 0.60m; Data Range: 20030805-20041006.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  16. CRED Subsurface Temperature Recorder (STR); NWHI, LAY; Long: -171.72941, Lat: 25.75893 (WGS84); Sensor Depth: 0.91m; Data Range: 20040924-20060730.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  17. CRED Subsurface Temperature Recorder (STR); NWHI, FFS; Long: -166.26132, Lat: 23.76897 (WGS84); Sensor Depth: 3.96m; Data Range: 20040917-20060905.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  18. CRED Subsurface Temperature Recorder (STR); CNMI, SAR; Long: 145.76789, Lat: 16.71058 (WGS84); Sensor Depth: 6.10m; Data Range: 20050918-20070524.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  19. CRED Subsurface Temperature Recorder (STR); NWHI, PHR; Long: -175.83133, Lat: 27.89797 (WGS84); Sensor Depth: 1.83m; Data Range: 20030802-20040927.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...

  20. CRED Subsurface Temperature Recorder (STR); NWHI, FFS; Long: -166.26198, Lat: 23.76883 (WGS84); Sensor Depth: 11.28m; Data Range: 20091009-20100513.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Coral Reef Ecosystem Division (CRED), NOAA Pacific Islands Fisheries Science Center (PIFSC) Subsurface Temperature Recorders (STR) provide a time series of...