Sample records for water physiological characteristics

  1. [Effects of different K fertilizer and water level on growth and physiological characteristics of Isatis indigotica].

    PubMed

    Yang, Juan-Juan; Guo, Qiao-Sheng; Chen, Su-Dan; Deng, Qiao-Hua

    2014-05-01

    The experiment included three potassium levels (K0 0 g x kg(-1), K1 0.33 g x kg(-1), K2 0.67 g x kg(-1)) and two water gradients (well watered and drought stress), then measured growth indicators, SOD, POD, CAT activities and concents of osmotic regulation substances. To explore the effects of K fertilizer and water on growth and physiological characteristics of Isatis indigotica, providing reference for improving drought resistance of I. indigotica. The result showed drought stress inhibited the growth and decreased the biomass of I. indigotica but K fertilizer can alleviate the drought stress. Compared with K0 treatment, K1, K2 treatment increased the biomass of overground part of by 89. 13% ,60. 87% under drought stress. The corresponding increase in soluble sugar content was 16.67%, 5.00%, and in proline content was 42.41%, 65.62%, respectively. SOD,POD and CAT activities was significantly improved in K1, K2 treatment in comparison with K0 treatment under drought stress, but soluble protein content significantly reduced. The conclusion is that appropriate amount of K fertilizer can increase the activities of antioxidase and the content of osmoregulation substance under drought stress, and improve drought resistance of I. indigotica. PMID:25282880

  2. [Water physiological characteristics and leaf traits of different aged Salix cheilophila on alpine sandy land].

    PubMed

    Liu, Hai-Tao; Jia, Zhi-Qing; Zhu, Ya-Juan; Yu, Yang; Li, Qing-Xue

    2012-09-01

    Taking 4-, 11-, 25-, and 37- year old Salix cheilophila stands on the alpine sandy land of Gonghe basin in Qinghai of West China as test objects, a laboratory test was conducted on their relative water deficit, water holding ability, specific leaf area (SLA), leaf mass-based nitrogen concentration (N(mass)) and phosphorous concentration (P(mass)), and N(mass)/P(mass), aimed to understand the variation patterns of the water physiological characteristics and leaf traits of different aged S. cheilophila on alpine sandy land. No significant difference was observed in the relative water deficit of the four stands. The daily mean value of water potential of the 37-year old stand was significantly lower, as compared with that of the other three stands, and the 4- and 11-year old stands had a significantly lower daily mean water potential than the 25-year old stand. The water loss rate of the 4-year old stand was significantly lower than that of the other three stands, and the 25-year old S. cheilophila stand had a significantly lower water loss rate than the 11-year old stand. The 4-year old stand also had a significantly lower SLA than the other three stands, implying its higher water use efficiency. The N(mass) of the 11-year old stand was significantly higher than that of the other three stands, and the 25-year old stand had a significantly higher N(mass) than the 37-year old stand, implying that the 11- and 25-year old stands had a higher photosynthetic capacity. The P(mass) of the 11-year old stand was significantly higher than that of the 25- and 37-year old stands, and the 4-year old stand had a significantly higher P(mass) than the 25-year old stand. The N(mass)/P(mass) of the four stands was 5.16-6.28, and the 25-year old stand had a significantly higher N(mass)/P(mass) than the 4- and 11-year old stands. The N(mass) of the four stands was significantly positively correlated with P(mass) the P(mass) was highly significantly negatively correlated with N(mass)/P(mass) and significantly nega- tively correlated with stand age, and the N(mass)/P(mass) was significantly positively correlated with stand age. It was suggested that S. cheilophila at its different developmental stages could have different ecological adaptive strategies. PMID:23285990

  3. The Effect of Water Stress on Some Morphological, Physiological, and Biochemical Characteristics and Bud Success on Apple and Quince Rootstocks

    PubMed Central

    Bolat, Ibrahim; Dikilitas, Murat; Ercisli, Sezai; Ikinci, Ali; Tonkaz, Tahsin

    2014-01-01

    The effects of different water stress (control, medium, and severe) on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67%) and Santa Maria/MA (70.33% and 15.33%) combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present. PMID:24741357

  4. Eco-physiological characteristics and variation in water source use between montane Douglas-Fir and lodgepole pine trees in southwestern Alberta

    NASA Astrophysics Data System (ADS)

    Andrews, S.; Flanagan, L. B.

    2009-12-01

    Winter weather on the Canadian prairies is now warmer and drier than 50 years ago and this has implications for soil water re-charge in montane ecosystems with consequences for tree and ecosystem function. We used measurements of the hydrogen isotope ratio of tree stem water to analyze the use of different water sources (winter snow melt, ground water, summer precipitation) in two montane forest sites, one dominated by Douglas-Fir and the other dominated by lodgepole pine trees. On average during the growing season (May-October) stem water in both Douglas-Fir and lodgepole pine trees was composed of 60% summer precipitation. However, during late summer Douglas-Fir trees showed an increased use of ground water as summer precipitation was minimal and ground water was accessible at the bottom of a relatively large soil reservoir. The low summer precipitation and reduced soil water availability in the shallow soils at the lodgepole pine site resulted in severely reduced photosynthetic capacity in late summer. Increased precipitation during the autumn resulted in recovery of photosynthetic gas exchange in lodgepole pine before winter dormancy was induced by low temperatures. Stomatal limitation of photosynthesis, as estimated from measurements of the carbon isotope composition of leaf tissue, was higher in Douglas-Fir than lodgepole pine. This was also associated with lower midday water potential values in Douglas-Fir and sapwood cross-sectional area that was only 70% of that measured in lodgepole pine. The vulnerability of xylem to loss of conductivity with declines in water potential was very similar between the two species. However, midday water potential in Douglas-Fir approached values where cavitation and loss of conductivity were apparent, while in lodgepole pine midday water potential was always much higher than the point at which loss of hydraulic conductivity occurred. These data suggest that, despite the presence of Douglas-Fir on deeper and higher quality soils, lodgepole pine appears to have eco-physiological characteristics that allow it to better withstand and recover from exposure to summer water deficits that may increase in association with trends to warmer and drier conditions.

  5. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY:

    EPA Science Inventory

    Twenty-one participants from Europe, North America and China convened in Chongqing, China, October 12-14, 2005, for the Eighth International Symposium in Fish Physiology, Toxicology and Water Quality. The subject of the meeting was "Hypoxia in vertebrates: Comparisons of terrestr...

  6. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY

    EPA Science Inventory

    Scientists from ten countries presented papers at the Fifth International Symposium on Fish Physiology, Toxicology, and Water Quality, which was held on the campus of the city University of Hong Kong on November 10-13, 1998. These Proceedings include 23 papers presented in sessi...

  7. Profiling in Basketball: Physical and Physiological Characteristics of Elite Players

    Microsoft Academic Search

    Sergej M. Ostojic; Sanja Mazic; Nenad Dikic

    2006-01-01

    Ostojic, S.M., S. Mazic, and N. Dikic. Profiling in basketball: Physical and physiological characteristics of elite players. J. Strength Cond. Res. 20(4)-.740-744. 2006.—The pur- pose of this study was to describe structural and functional char- acteristics of elite Serbian basketball players and to evaluate whether players in different positional roles have different phys- ical and physiological profiles. Five men's basketball

  8. [Seed growth characteristics of Ginkgo biloba and its physiological change].

    PubMed

    Wang, J; Wang, J; Xin, X

    2000-08-01

    The length, width, volume and weight of Ginkgo biloba seed were measured, and the concentrations of water, sugars, fatty acids and amino acids in seed growth process were analyzed. A typical "S" seed growth curve was found, and the length, width, volume, weight and absolute water content all showed the similar changes during growing period. With the growing of ssed, the concentrations of physiological substances in seeds showed regular changes and had their own characteristics. The total amount of sugars appeared to be an increasing trend at the later stage of seed growth, indicating that sugars are the main nutrition substance accumulated in seeds. The concentrations of various substances in matured seeds were starch 8.4%, glucose 6.7%, fructose 4.2%, polysaccharide 0.02%, disaccharide 0.01%, myristic acid 10.6%, palmitic acid 4.1%, flax acid 2.4%, stearic acid 1.9%, oleic acid 1.1%, and linoleic acid 0.4%. Fifteen types of free amino acids were detected in matured seeds, with total content of 1.56 g.100 g-1FW. Among them, lysine aspartic acid, alanine, arginine, histidine, glutamic acid, and isoleucine were dominant, and their concentrations were 0.287%, 0.163%, 0.136%, 0.133%, 0.123%, 0.115%, 0.095%, respectively. PMID:11767666

  9. Aquaporin water channels in gastrointestinal physiology

    PubMed Central

    Ma, Tonghui; Verkman, A S

    1999-01-01

    Fluid transport is a major function of the gastrointestinal (GI) tract with more than 9 litres of fluid being absorbed or secreted across epithelia in human salivary gland, stomach, the hepatobiliary tract, pancreas, small intestine and colon. This review evaluates the evidence that aquaporin-type water channels are involved in GI fluid transport. The aquaporins are a family of small (?30 kDa) integral membrane proteins that function as water channels. At least seven aquaporins are expressed in various tissues in the GI tract: AQP1 in intrahepatic cholangiocytes, AQP4 in gastric parietal cells, AQP3 and AQP4 in colonic surface epithelium, AQP5 in salivary gland, AQP7 in small intestine, AQP8 in liver, pancreas and colon, and AQP9 in liver. There are functional data suggesting that some GI cell types expressing aquaporins have high or regulated water permeability; however, there has been no direct evidence for a role of aquaporins in GI physiology. Recently, transgenic mice have been generated with selective deletions of various aquaporins. Preliminary evaluation of GI function suggests a role for AQP1 in dietary fat processing and AQP4 in colonic fluid absorption. Further study of aquaporin function in the GI tract should provide new insights into normal GI physiology and disease mechanisms, and may yield novel therapies to regulate fluid movement in GI diseases. PMID:10332084

  10. A simulation model of vegetation temperature based on physiological characteristics

    NASA Astrophysics Data System (ADS)

    Lin, Wei; Wang, Ji-yuan; Chen, Yu-hua; Wang, Ji-jun; Su, Rong-hua

    2014-11-01

    To simulate vegetation temperature is an important part in the thermal infrared simulation. In previous physical models, the physiological characteristics of vegetation has only considered the influence of transpiration to temperature, but without respiration, and the aerodynamics model which has been used before needs more model parameters and they are difficult to obtain. In the present paper, a transpiration rate model has been used, in which the latent heat component of the vegetation has been optimized and the respiration component has been joined. Then the physiological model of vegetation temperature simulation has been established which improves the original vegetation energy budget theory. Experimental verification and comparison shows that the maximum simulation error of physiological model is within 2°, the average error is within 1°. It seems that the simulation accuracy is significantly better than the previous physical model that will improve the overall thermal infrared simulation accuracy.

  11. Impact of leaf physiological characteristics on seasonal variation in CO 2, latent and sensible heat exchanges over a tree plantation

    Microsoft Academic Search

    Katsunori Tanaka; Yoshiko Kosugi; Akihiro Nakamura

    2002-01-01

    This study investigated the impact of leaf physiological characteristics on CO2, sensible heat, and latent heat exchanges over a plant community.Measurements were carried out over plantation trees using an eddy correlation system, under well-watered soil conditions for several days spanning the year, and under soil drought conditions during autumn only. The following leaf physiological characteristics were investigated: the maximum rate

  12. THE PHYSIOLOGICAL EFFECTS OF WATER vs. GATORADE DURING PROLONGED EXERCISE

    Microsoft Academic Search

    Ashley Danielson; Lynn Morris; Lindi Neiderhauser; Kasey Stanek; Jennifer Wolter

    Danielson , A.R., Morris, L., Neiderhauser, L., Stanek, K., Wolter, J. The Physiological effects of water vs. Gatorade during prolonged exercise. J. Undergrad. Kin. Res. 2006; 1(1):15-22. The purpose of this study was to investigate the physiological effects of water vs. Gatorade during prolonged exercise. Subjects consisted of 10 recreationally active females between the ages 19 and 22. Each participant

  13. [Effect of red and blue spectrum on photosynthesis physiological characteristics of two ecotypes of Leymus chinensis].

    PubMed

    Zhou, Chan; Yang, Yun-Fei; Wang, Kun

    2008-07-01

    Photosynthesis physiological characteristics of two ecotypes of Leymus chinensis were studied under different red and blue light excitation by LED red and blue lamp-house. Photosynthesis did not carry on under red and blue light of 50 micromol x m(-2) x s(-1). When red and blue light intensity was increased, photosynthesis rate, stoma limit value and transpiration rate of the two ecotypes of Leymus chinensis were all increased. But photosynthesis rate stopped increasing under red and blue light of 1 150 micromol x m(-2) x s(-1) for grey-green ecotype Leymus chinensis and of 907 micromol x m(-2) x s(-1) for yellow-green ecotype Leymus chinensis, which is known as light saturation. And the effect of blue light on photosynthesis became weaker than red light under higher light intensity. Increasing light intensity can promote plant photosynthesis rate in the range of low light intensity. But when light intensity reaches light saturation, photosynthesis rate does not increases but decreases. Because though light quantum numbers is increasing, the numbers of coloring mater does not change and is saturated. On the other hand, when the light intensity is of light saturation, the stoma limit value was increased and the transpiration rate was decreased in order to reduce water waste. When light intensity reaches the value that plant can bear, the plant will automatically close stoma in order to decrease transpiration and to save water. Plant balances every physiological index and makes sure that physiology damage is the least and production is the greatest. Although grey-green ecotype Leymus chinensis has lower stoma limit and higher water waste, it also has higher photosynthesis rate than yellow-green ecotype Leymus chinensis. And the photosynthesis capability and physiology adaptation of grey-green ecotype Leymus chinensis is greater than that of yellow-green ecotype Leymus chinensis. PMID:18844135

  14. Boxelder water sources and physiology at perennial and ephemeral stream sites in Arizona.

    PubMed

    Kolb, T E; Hart, S C; Amundson, R

    1997-03-01

    To assess the influence of stream water on leaf gas exchange and water potential in different sized boxelder trees (Acer negundo L.), we compared these characteristics in trees growing beside a perennial stream and a nearby ephemeral stream in a montane-riparian forest in northern Arizona. Patterns of tree water use were quantified by stable isotope analysis (delta(18)O). Physiological characteristics were similar for large and small trees. Similarity between sites in predawn and daytime water potentials and xylem delta(18)O indicated that stream water was not a physiologically important water source. Seasonal and site variations in light-saturated net photosynthetic rate were significantly related to leaf-to-air vapor pressure deficit (r = -0.691) and foliar nitrogen concentration (r = 0.388). Although deep water was the dominant water source, surface soil water was utilized following precipitation, especially by small trees. We conclude that net carbon gain and severity of water stress are only weakly coupled to stream water availability. PMID:14759869

  15. SYMPOSIUM IN ITALY: FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY

    EPA Science Inventory

    Scientists from Europe, North America and South America convened in Capri, Italy, April 24-28, 2006 for the Ninth International Symposium on Fish Physiology, Toxicology, and Water Quality. The subject of the meeting was Eutrophication: The toxic effects of ammonia, nitrite and th...

  16. Physiological Effects of Trace Elements and Chemicals in Water

    ERIC Educational Resources Information Center

    Varma, M. M.; And Others

    1976-01-01

    The physiological effects on humans and animals of trace amounts of organic and unorganic pollutants in natural and waste waters are examined. The sensitivity of particular organs and species is emphasized. Substances reviewed include mercury, arsenic, cadmium, lead, chromium, fluorides, nitrates and organics, including polychlounated biphenyls.…

  17. Zinc deficiency affects physiological and anatomical characteristics in maize leaves.

    PubMed

    Mattiello, Edson M; Ruiz, Hugo A; Neves, Julio C L; Ventrella, Marília C; Araújo, Wagner L

    2015-07-01

    Zinc (Zn) is an essential microelement involved in several plant physiological processes. Therefore, it is important to identify Zn deficiencies promptly-before extensive damage occurs to the plant. The diagnostic tools that are used to identify Zn deficiencies are very important in areas where Zn deficiencies occur. Such diagnostic tools are vital for nutritional management and fertilizer recommendations. The current study investigated the effects of Zn deficiency on maize plants by recording a number of physiological and anatomical parameters. A Zn omission trial (from 0 to 22 days) was carried out to produce plants that had varying degrees of Zn deficiency. Typical symptoms of Zn deficiency (e.g. chlorotic stripes and purple shades on the edges and leaf sheath) appeared 16 days after the omission of Zn from nutrient solutions. As the time of Zn omission increased, there were significant decreases in net photosynthesis, stomatal conductance, maximal efficiency of photosystem I (evaluated by Fv/Fm), biomass (dry weight) and Zn concentrations in plants. Zinc-deficient plants also had a lower vascular bundle proportion coupled with a higher stomata density. These physiological and anatomical changes negatively impacted plant growth. Moreover, they occurred before visible symptoms of Zn deficiency were observed. Zinc concentrations were recorded for younger leaves, rather than for more mature leaves, which is usually recommended for plant analysis. The results demonstrate that the analysis of Zn in young leaves of maize is a very sensitive indicator of Zn status. PMID:26135475

  18. Physiological characteristics of mercury uptake by two estuarine species

    USGS Publications Warehouse

    Luoma, S.N.

    1977-01-01

    Rapid uptake and slow loss of Hg will result from short exposures of some organisms to this metal, due to the transformation of Hg to a slowly exchanging form within the organisms. The extent of the difference between exposure time and depuration time will depend upon the rate of transformation during uptake. For the polychaete worm Neanthes succinea and the shrimp Palaemon debilis such transformations are extremely rapid. The exchange of Hg from the slowly exchanging compartment is similar among a wide variety of species. Thus, interspecies differences in susceptibility to Hg may be determined by differences in biochemical transformation rates and physiological permeability to the metal. ?? 1977 Springer-Verlag.

  19. Physiology

    ERIC Educational Resources Information Center

    Kay, Ian

    2008-01-01

    Underlying recent developments in health care and new treatments for disease are advances in basic medical sciences. This edition of "Webwatch" focuses on sites dealing with basic medical sciences, with particular attention given to physiology. There is a vast amount of information on the web related to physiology. The sites that are included here…

  20. Anthropometric, physiological and performance characteristics of elite team-handball players

    Microsoft Academic Search

    Anis Chaouachi; Matt Brughelli; Gregory Levin; Nahla Ben Brahim Boudhina; John Cronin; Karim Chamari

    2009-01-01

    The objective of this study was to provide anthropometric, physiological, and performance characteristics of an elite international handball team. Twenty-one elite handball players were tested and categorized according to their playing positions (goalkeepers, backs, pivots, and wings). Testing consisted of anthropometric and physiological measures of height, body mass, percentage body fat and endurance ([Vdot]O2max), performance measures of speed (5, 10,

  1. NRES 725 PLANT PHYSIOLOGICAL ECOLOGY Reading List Water Balance of Plants

    E-print Network

    Nowak, Robert S.

    1 NRES 725 ­ PLANT PHYSIOLOGICAL ECOLOGY Fall 2008 Reading List ­ Water Balance of Plants I) Water Balance of Plants A) Water potential B) Soil, plant, air continuum C) Physiological control 1) Roots and water uptake 2) Hydraulic conductivity 3) Stomatal conductance and transpiration Recommended Kirkham (05

  2. Attentional and physiological characteristics of patients with dental anxiety.

    PubMed

    Johnsen, Bjørn Helge; Thayer, Julian F; Laberg, Jon C; Wormnes, Bjørn; Raadal, Magne; Skaret, Erik; Kvale, Gerd; Berg, Einar

    2003-01-01

    Twenty patients with dental anxiety were investigated while seated in a dental chair in a dental clinic. Heart rate (HR), heart rate variability (HRV), and skin conductance level (SCL) were recorded while the patients were exposed to scenes of dental treatment as well as a Stroop attentional task. Results showed an attentional bias with longer manual reaction times (RT's) to the incongruent compared to the congruent color words as well as the threat compared to the neutral words. Longer RT's to the incongruent and the threat words were found in the low HRV patients compared to the high HRV patients. Furthermore, all patients showed an increase in HR during exposure and the Stroop task compared to baseline. The HRV showed a decrease during the exposure and the Stroop task compared to baseline. HR and HRV did not differ between exposure and the Stroop task. Moreover, HR and HRV did not return to baseline levels during the recovery period. The SCL showed an increase from baseline to exposure, from exposure to the Stroop task and a decrease in the recovery phase. Results showed the importance of vagal cardiac control in attentional, emotional, and physiological processes in patients suffering from dental fear. PMID:12464290

  3. [In life determination of the physiological status of decapod crustaceans (Crustacea: Decapoda) by hematological characteristics].

    PubMed

    Aleksandrova, E N; Kovacheva, N P

    2010-01-01

    The application of hematological analysis techniques to detecting the physiological status of the economically valued decapods during their culturing, and in monitoring of the condition of their natural populations, is restrained by the incomplete knowledge of these invertebrates circulatory system and its properties. Scarce data on the use of hematological indicators for determining the physiological status of decapods may be found sporadically in published sources; there is shortage of basic standards needed for interpretation of the analytical results. In this regard the paper considers some data on the major properties of hemolymph and its cellular elements; on methods of their examination; and on the results of application of hematological characteristics to assessing the physiological condition of various species of decapods. The hematological indicators suitable for the analysis of live decapods include: time of coagulation and buffer characteristic of hemolymph; concentration of total proteins, copper, calcium, glucose and lactates in it; total number of hemocytes with the consideration of granulocytes share. PMID:20469604

  4. Effects of potassium nutrition on physiological processes and derivative spectrum characteristics of corn plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the effects of potassium nutrition on growth, development and various other physiological processes and the spectrum characteristics of corn. Corn seeds were shown in sand culture using 3.8L pots in SPAR chambers with day/night temperatures of 30/220C and Carbon Di...

  5. Root physiological and morphological characteristics of 24 rice varieties selected for diverse grain mineral

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accumulate a mineral in the grain, a plant must first absorb that mineral from the soil. Root physiological characteristics, such as exudation of organic acids or oxygen, impact the availability, solubility and mobility of minerals in the soil, ultimately impacting the amount of minerals absorbe...

  6. Physiological characteristics of the best Eritrean runners—exceptional running economy

    Microsoft Academic Search

    Alejandro Lucia; Jonathan Esteve-Lanao; Jesus Olivan; Felix Gomez-Gallego

    Despite their young age, limited training history, and lack of running tradition compared with other East African endurance athletes (e.g., Kenyans and Ethiopians), male endurance runners from Eritrea have recently attained important running successes. The purposes of our study were (i) to document the main physical and physiological characteristics of elite black Eritrean distance runners (n = 7; age: 22

  7. Taxonomical and physiological characteristics of H2/CO2-utilizing acetogenic bacteria from the human colon

    E-print Network

    Boyer, Edmond

    Taxonomical and physiological characteristics of H2/CO2-utilizing acetogenic bacteria from-5-10-! dilution of human feces using a modified AC21 medium with H2/CO2 as sole energy source. Among the fifteen identified as Streptococcus species. All these species were able to grow autotrophically using H2/CO2

  8. Correlations between Morphological, Molecular Biological, and Physiological Characteristics in Clinical and Nonclinical Isolates of Acanthamoeba spp

    Microsoft Academic Search

    JULIA WALOCHNIK; ANDREAS OBWALLER; HORST ASPOCK

    2000-01-01

    Eleven Acanthamoeba isolates, obtained from Acanthamoeba keratitis patients, from contact lens cases of non-Acanthamoeba keratitis patients, from asymptomatic individuals, from necrotic tissue, and from tap water and two reference strains were investigated by morphological, molecular biological, and physiological means in order to discriminate clinically relevant and nonrelevant isolates. All clinically relevant isolates showed Acanthamoeba sp. group II morphology. 18S ribosomal

  9. Meta-analysis of digital game and study characteristics eliciting physiological stress responses.

    PubMed

    van der Vijgh, Benny; Beun, Robbert-Jan; Van Rood, Maarten; Werkhoven, Peter

    2015-08-01

    Digital games have been used as stressors in a range of disciplines for decades. Nonetheless, the underlying characteristics of these stressors and the study in which the stressor was applied are generally not recognized for their moderating effect on the measured physiological stress responses. We have therefore conducted a meta-analysis that analyzes the effects of characteristics of digital game stressors and study design on heart rate, systolic and diastolic blood pressure, in studies carried out from 1976 to 2012. In order to assess the differing quality between study designs, a new scale is developed and presented, coined reliability of effect size. The results show specific and consistent moderating functions of both game and study characteristics, on average accounting for around 43%, and in certain cases up to 57% of the variance found in physiological stress responses. Possible cognitive and physiological processes underlying these moderating functions are discussed, and a new model integrating these processes with the moderating functions is presented. These findings indicate that a digital game stressor does not act as a stressor by virtue of being a game, but rather derives its stressor function from its characteristics and the methodology in which it is used. This finding, together with the size of the associated moderations, indicates the need for a standardization of digital game stressors. PMID:25950613

  10. Water stress and recovery in the performance of two Eucalyptus globulus clones: physiological and biochemical profiles.

    PubMed

    Correia, Barbara; Pintó-Marijuan, Marta; Neves, Lucinda; Brossa, Ricard; Dias, Maria Celeste; Costa, Armando; Castro, Bruno B; Araújo, Clara; Santos, Conceição; Chaves, Maria Manuela; Pinto, Glória

    2014-04-01

    Eucalyptus plantations are among the most productive forest stands in Portugal and Spain, being mostly used for pulp production and, more recently, as an energy crop. However, the region's Mediterranean climate, with characteristic severe summer drought, negatively affects eucalypt growth and increases mortality. Although the physiological response to water shortage is well characterized for this species, evidence about the plants' recovery ability remains scarce. In order to assess the physiological and biochemical response of Eucalyptus globulus during the recovery phase, two genotypes (AL-18 and AL-10) were submitted to a 3-week water stress period at two different intensities (18 and 25% of field capacity), followed by 1 week of rewatering. Recovery was assessed 1 day and 1 week after rehydration. Drought reduced height, biomass, water potential, NPQ and gas exchange in both genotypes. Contrarily, the levels of pigments, chlorophyll fluorescence parameters (F(v) /F(m) and (?PSII)), MDA and ABA increased. During recovery, the physiological and biochemical profile of stressed plants showed a similar trend: they experienced reversion of altered traits (MDA, ABA, E, g(s), pigments), while other parameters did not recover ((?PSII), NPQ). Furthermore, an overcompensation of CO(2) assimilation was achieved 1 week after rehydration, which was accompanied by greater growth and re-establishment of oxidative balance. Both genotypes were tolerant to the tested conditions, although clonal differences were found. AL-10 was more productive and showed a more rapid and dynamic response to rehydration (namely in carotenoid content, (?PSII) and NPQ) compared to clone AL-18. PMID:24117924

  11. Physiological and chemical characteristics of field-and mountain-cultivated ginseng roots

    Microsoft Academic Search

    Yong Eui Choi; Yong Suk Kim; Myong Jong Yi; Wan Geun Park; Jae Seon Yi; Seong Ryeol Chun; Sang Sup Han; Sung Jae Lee

    2007-01-01

    Demand is increasing for mountain-cultivatedPanax ginseng (MCG) because its quality is considered superior to that of field-cultivated ginseng (FCG). However, MCG grows very slowly,\\u000a and the factors that might affect this are unknown. In addition, little information is available about the physiological characteristics\\u000a of its roots. Here, we investigated local soil environments and compared the histological and chemical properties of

  12. Physiological characteristics of platelet\\/circulatory serotonin: study on a large human population

    Microsoft Academic Search

    Branimir Jernej; Miroslav Banovi?; Lipa Cicin-Šain; Dubravka Hranilovi?; Melita Balija; Darko Oreškovi?; Vera Folnegovi?-Šmalc

    2000-01-01

    The aim of this work was the study of platelet\\/circulatory serotonin (5-hydroxytryptamine, 5-HT), specifically alternative ways of its measurement and main physiological characteristics. The study was performed on a large human population (N=500) of blood donors of both sexes over the course of a longer time period (17 months). Owing to the heterogeneity in measurement of circulatory serotonin encountered in

  13. Histocytological characteristics of Eucalyptus urophylla  ×  Eucalyptus grandis shoot apical meristems of different physiological ages

    Microsoft Academic Search

    François Mankessi; Aubin Saya; Fabienne Montes; Marc Lartaud; Jean-Luc Verdeil; Olivier Monteuuis

    2011-01-01

    Histocytological characteristics of Eucalyptus urophylla × Eucalyptus grandis shoot apical meristems (SAMs) were described, comparing five outdoor and in vitro sources of akin genotypes differing in\\u000a their physiological age. The size and the number of cells of the five zones identified within each SAM, i.e. the two tunica\\u000a layers (L1 and L2), the central mother cells (CMC), the peripheral zone (PZ) and

  14. Linkage of within vineyard soil properties, grapevine physiology, grape composition and sensory characteristics in a premium wine grape vineyard.

    NASA Astrophysics Data System (ADS)

    Smart, David; Hess, Sallie; Ebeler, Susan; Heymann, Hildegarde; Plant, Richard

    2014-05-01

    Analysis of numerous vineyards has revealed a very high degree of variation exists at the within vineyard scale and may outweigh in some cases broader mesoclimatic and geological factors. For this reason, selective harvest of high quality wine grapes is often conducted and based on subjective field sensory analysis (taste). This is an established practice in many wine growing regions. But the relationships between these subjective judgments to principle soil and grapevine physiological characteristics are not well understood. To move toward greater understanding of the physiological factors related to field sensory evaluation, physiological data was collected over the 2007 and 2008 growing seasons in a selectively harvested premium production Napa Valley estate vineyard, with a history of selective harvesting based on field sensory evaluation. Data vines were established and remained as individual study units throughout the data gathering and analysis phase, and geographic information systems science (GIS) was used to geographically scale physiological and other data at the vineyard level. Areas yielding grapes with perceived higher quality (subjective analysis) were characterized by vines with 1) statistically significantly lower (P < 0.05) leaf water potential (LWP) both pre-dawn (PD) and midday (MD), 2) smaller berry diameter and weight, 3) lower pruning weights, and 4) higher soluble solids (Brix). Strong positive correlations emerged between June ?PD and pre-harvest grape berry diameter (R2 = 0.616 in 2007 and 0.413 in 2008) and similar strong correlations existed for berry weight (R2 = 0.626 in 2007 and 0.554 in 2008). A trained sensory panel performed a sensory analysis and characterized fruit using and a multivariate, principal components, analysis (PCA). This approach indicated that grapes from vines with lowest midday leaf water potential at veraison (< -1.5 MPa) had sweeter and softer pulp, absence of vegetal characteristics, and browner and crunchier seeds, while grapes from vines of > -1.5 MPa were characterized by vegetal flavors and astringent and bitter seeds and skins. Data from vines were grouped into vines experiencing MD at veraison of < -1.5 MPa versus vines with MD > -1.5 MPa and subjected to single factor analysis of variance. This analysis revealed statistically significant differences (P less than 0.05) in many of the above properties - berry diameter, weight, pulp, and fruity versus vegetal characteristic. The groupings corresponded to the areas described as producing higher and lower quality fruit, respectively, based on field taste evaluation. Metabolomic analysis of grape skins from these two groups showed statistically significant differences in accumulation of amino acids and organic acids. Our results suggest there is not a continuous relationship between physiological water status (stress) and grape sensory characteristics, but rather the presence of an inflection point that may be related to early season PD in controlling grape development as well as composition. Soils analyses revealed the preferred fruit was on vines in areas where soils were shallower rather than any definitive characteristic related to particle size distribution or nutrient availability, suggesting that in this vineyard soil available water is the major controlling factor.

  15. Landscape and plant physiological controls on water dynamics and forest productivity within a watershed

    NASA Astrophysics Data System (ADS)

    Hu, Jia; Jencso, Kelsey; Looker, Nathaniel; Martin, Justin; Hoylman, Zachary

    2015-04-01

    Across the Western U.S., declining snowpacks have resulted in increased water limitation, leading to reduced productivity in high elevation forests. While our current understanding of how forests respond to climate change is typically focused on measuring/modeling the physiological responses and climate feedbacks, our study aims to combine physiology with hydrology to examine how landscape topography modulates the sensitivity of forests to climate. In a forested watershed in Western Montana, we linked climate variability to the physical watershed characteristics and the physiological response of vegetation to examine forest transpiration and productivity rates. Across the entire watershed, we found a strong relationship between productivity and the topographic wetness index, a proxy for soil moisture storage. However, this relationship was highly dependent on the intensity of solar radiation, suggesting that at high elevations productivity was limited by temperature, while at low elevations productivity was limited by moisture. In order to identify the mechanisms responsible for this relationship, we then examined how different coniferous species respond to changing environmental and hydrologic regimes. We first examined transpiration and productivity rates at the hillslope scale at four plots, ranging in elevation and aspect across the watershed. We found trees growing in the hollows had higher transpiration and productivity rates than trees growing in the side slope, but that these differences were more pronounced at lower elevations. We then used oxygen isotope to examine water source use by different species across the watershed. We found that trees growing in the hollows used snowmelt for a longer period. This was most likely due to upslope subsidies of snowmelt water to the hollow areas. However, we found that trees growing at lower elevations used proportionally more snowmelt than trees at the higher elevations. This was most likely due to the trees at lower elevation depending on deeper, more reliable water when the upper soils dried down during midsummer. These observations suggest that landscape topography influences the availability of soil water, which influences tree transpiration and productivity rates, thereby leading to watershed patterns of productivity.

  16. Tolerance and physiological responses of Phragmites australis to water deficit

    E-print Network

    Brix, Hans

    to water stress. Individual plants were grown under conditions of unrestricted water supply and compared with groups of plants receiving 60, 30, 15 or 5% of previous daily water requirements, respectively. Water growth were very sensitive to water availability and were reduced when plants were subjected to fairly

  17. Physiological, anthropometric, strength, and muscle power characteristics correlates with running performance in young runners.

    PubMed

    Dellagrana, Rodolfo A; Guglielmo, Luiz G A; Santos, Bruno V; Hernandez, Sara G; da Silva, Sérgio G; de Campos, Wagner

    2015-06-01

    Dellagrana, RA, Guglielmo, LGA, Santos, BV, Hernandez, SG, da Silva, SG, and Campos, W. Physiological, anthropometric, strength, and muscle power characteristics correlates with running performance in young runners. J Strength Cond Res 29(6): 1584-1591, 2015-The purpose of this study was to investigate the relationship between physiological, anthropometric, strength, and muscle power variables and a 5-km time trial (5kmT) in young runners. Twenty-three runners volunteered to participate in this study. Height, body mass, body fat, and fat-free mass (FFM) were measured. The subjects underwent laboratory testing to determine maximal oxygen uptake ((Equation is included in full-text article.)), velocity at ventilatory threshold (VVT), running economy (RE), velocity associated with maximal oxygen uptake ((Equation is included in full-text article.)), and peak velocity (PV). Peak torque, total work, and power were measured by an isokinetic dynamometer at 60°·s and 240°·s angular velocities. Right and left knee flexor and extensor torques were evaluated. Finally, the participants performed a 5kmT. Multiple regression and correlation analysis were used to determine the variables that significantly related to 5kmT. Strength and muscle power variables did not correlate with 5kmT. However, most physiological variables were associated with 5kmT. Velocity at ventilatory threshold alone explains 40% of the variance in 5kmT. The addition of the RE at speed 11.2 km·h (RE11.2) and FFM to the prediction equation allowed for 71% of the adjusted variance in 5kmT to be predicted. These results show that strength and muscle power variables are not good predictors of 5kmT; however, the physiological variables presented high prediction capacity in the 5kmT. Moreover, the anthropometric measures showed significant influence in performance prediction. PMID:26010795

  18. Water Balance in Terrestrial Animals Recurring themes in physiological ecologyRecurring themes in physiological ecology Economy: balancing gains and lossesEconomy: balancing gains and losses

    E-print Network

    Cochran-Stafira, D. Liane

    in physiological ecology Economy: balancing gains and lossesEconomy: balancing gains and losses water, heat lossevaporative water loss Surface areaSurface area--toto--volume ratio increases asvolume ratio increases as body size decreasesbody size decreases Evaporative water loss increases asEvaporative water loss

  19. Physiological and genetic control of water stress tolerance in zoysiagrass 

    E-print Network

    Dewey, Daniel Wade

    2006-04-12

    Significant cultivar difference in many water stress responses of zoysiagrass (Zoysia japonica (Steud.) and Zoysia matrella (L.) Merr.) are shown in this study. Of the four cultivars, Palisades was the most water stress ...

  20. The influence of physical and physiological characteristics of vegetation on their hydrological response

    NASA Astrophysics Data System (ADS)

    Roberts, John

    2000-10-01

    In the past, plant physiological studies have contributed substantial understanding of the behaviour of plants with respect to hydrological processes in vegetation and the effects of deficits and surpluses of water on plants. In this paper progress in some important current fields of plant physiological research, with particular relevance to ecohydrology, are examined.The control of water loss by plants, through manipulation of stomatal opening and amounts of foliage, is examined. Models that describe the control of stomatal behaviour by a combination of hydraulic and chemical signalling combined with transpiration flux have emerged in recent years. There is, however, a need for detailed testing of such models in field situations, particularly with large woody vegetation. Forest transpiration is examined in detail. In traditional broadleaves and conifers in temperate regions transpiration is modest and similar between forests. A number of factors are considered to explain the situation. A strong negative association of stomatal conductance with air humidity deficit is thought to relate to the low overall transpiration. High transpiration rates are associated with large stomatal conductances, which show little reduction in association with increased air humidity deficits. Soil moisture deficits have less impact in forests with inherently low transpiration.There is growing interest in the mechanisms of competition for soil water between plants growing together. Studies have been aided recently by the feasibility of direct measurements of root hydraulic conductivity. Further understanding of patterns of water uptake by roots has emerged, with new approaches involving sap flow and stable isotope techniques.Physiologists have provided considerable insight into controls of water loss at the individual leaf or plant level. At the larger scale of the vegetation stand, the leaf control may be modified considerably depending on the structure of the vegetation, which influences coupling with the atmosphere. In tall, rough vegetation, such as forests and woodlands, the coupling is strong, so that the stomatal control of transpiration at the leaf level is maintained at the canopy level.In recent studies with forest vegetation, declines in transpiration have been observed to occur after a few to several decades from establishment of the forest. These reductions in transpiration can have significant influences on streamflow. In parallel, physiological studies have provided explanations both in terms of declining leaf area but also due to reductions in stomatal conductance, as a consequence of reductions in hydraulic conductivity of woody tissues.

  1. Effect of Fresh Orange Juice Intake on Physiological Characteristics in Healthy Volunteers

    PubMed Central

    Asgary, Sedigheh; Keshvari, Mahtab; Afshani, Mohammad Reza; Javanmard, Shaghayegh Haghjooy

    2014-01-01

    Background. Impaired endothelial function is a predictor of cardiovascular events. Orange juice (OJ) is rich in dietary flavonoids and could inhibit oxidative stress and inflammatory responses. We examined the effects of commercial (COJ) and fresh orange juice (FOJ) on endothelial function and physiological characteristics in healthy humans. Materials and Methods. Twenty-two healthy volunteers years were enrolled in a single blind randomized crossover controlled trial. The two groups consumed either COJ for the first 4 weeks and then FOJ (CFOJ, 4 weeks), or FOJ for the first 4 weeks and then COJ (FCOJ, 4?weeks). We assessed endothelial function by measuring flow-mediated dilation, serum concentrations of lipids, apolipoproteins A and B (apo A-1 and apo B), and inflammatory markers such as vascular endothelial adhesion molecule 1 (VCAM-1), E-selectin, high-sensitivity C-reactive protein (hs-CRP), and interleukin-6. Results. Consumption of both juices decreased VCAM, hs-CRP, and E-selectin but increased apo A-1. A decline in LDL occurred in the FOJ group. There were no differences between the characteristics of two groups, with the exception of apo A-1 levels that were increased with both forms of OJ. The largest variations occurred with hs-CRP, VCAM in both groups. Conclusion. Consumption of COJ and FOJ produced beneficial effects on the physiological characteristics of healthy volunteers. Although these results could encourage the consumption of OJ, intervention studies are needed to determine the long-term effects of these types of OJ on metabolic and cardiovascular endpoints. PMID:24967267

  2. Sugarcane growth and physiological responses to water deficit stress on organic and sand soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane (Saccharum spp.) genotype selection has been more successful for organic (muck) than sand soils in Florida, perhaps due to differences in water availability. A greenhouse study was conducted at Canal Point, Florida to compare sugarcane physiological responses to water deficit stress during...

  3. Plant physiology Role of awns in ear water-use efficiency

    E-print Network

    Paris-Sud XI, Université de

    Plant physiology Role of awns in ear water-use efficiency and grain weight in barley J Bort net photosynthesis and water-use efficiency (WUE: net photosynthesis/transpiration) of ears and flag photosynthesis of awned ears was markedly higher than that of awnless ears, until 3 weeks after anthesis

  4. Physiological responses to hyper-saline waters in sailfin mollies ( Poecilia latipinna)

    Microsoft Academic Search

    R. J. Gonzalez; J. Cooper; D. Head

    2005-01-01

    We examined the ionoregulatory physiology and biochemistry of the teleost sailfin molly (Poecilia latipinna), an inhabitant of salt marshes along the gulf coast, during exposure to hyper-saline waters (salinity range 35–95 ppt). Mollies were able to tightly control plasma Na+ and Cl? concentrations and tissue water levels up to 65 ppt, but at higher salinities plasma ion levels began to

  5. Bioenergetics and thermal physiology of American water shrews ( Sorex palustris )

    Microsoft Academic Search

    R. W. Gusztak; R. A. MacArthur; K. L. Campbell

    2005-01-01

    Rates of O 2 consumption and CO 2 production, telemetered body temperature ( T b) and activity level were recorded from adult and subadult water shrews ( Sorex palustris) over an air temperature ( T a) range of 3–32°C. Digesta passage rate trials were conducted before metabolic testing to estimate the minimum fasting time required for water shrews to achieve

  6. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    PubMed

    Rosado, Bruno H P; De Mattos, Eduardo A; Sternberg, Leonel Da S L

    2013-09-01

    During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models. PMID:24068091

  7. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Water Landing Characteristics of a Reentry Capsule. Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions. [Entire movie available on DVD from CASI as Doc ID 20070030955. Contact help@sti.nasa.gov

  8. Microbiological characteristics and physiological functionality of new records of yeasts from wild flowers in yokjido, Korea.

    PubMed

    Hyun, Se-Hee; Lee, Jong-Soo

    2014-06-01

    Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic á-glucosidase inhibitory activity. PMID:25071392

  9. Microbiological Characteristics and Physiological Functionality of New Records of Yeasts from Wild Flowers in Yokjido, Korea

    PubMed Central

    Hyun, Se-Hee

    2014-01-01

    Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic á-glucosidase inhibitory activity. PMID:25071392

  10. Physiological and genetic control of water stress tolerance in zoysiagrass

    E-print Network

    Dewey, Daniel Wade

    2006-04-12

    solutes used in osmotic adjustment are glycerol, glycine betaine, potassium, proline, sugars, and sugar alcohols like mannitol and sorbitol (Kramer and Boyer, 1995; Taiz and Zeiger, 2002). Osmotic adjustment is a common water stress response in many...

  11. Water protein dynamic coupling and new opportunities for probing it at low to physiological temperatures in aqueous solutions

    SciTech Connect

    Mamontov, Eugene [ORNL; Chu, Xiang-Qiang [ORNL

    2012-01-01

    Both the structure and dynamics of biomolecules are known to be essential for their biological function. In the dehydrated state, the function of biomolecules, such as proteins, is severely impeded, so hydration is required for bioactivity. The dynamics of the hydrated biomolecules and their hydration water are related - but how closely? The problem involves several layers of complexity. Even for water in the bulk state, the contribution from various dynamic components to the overall dynamics is not fully understood. In biological systems, the effects of confinement on the hydration water further complicate the picture. Even if the various components of the hydration water dynamics are properly understood, which of them are coupled to the protein dynamics, and how? The studies of protein dynamics over the wide temperature range, from physiological to low temperatures, provide some answers to these question. At low temperatures, both the protein and its hydration water behave as solids, with only vibrational degrees of freedom. As the temperature is increased, non-vibrational dynamic components start contributing to the measurable dynamics and eventually become dominant at physiological temperatures. Thus, the temperature dependence of the dynamics of protein and its hydration water may allow probing various dynamic components separately. In order to suppress the water freezing, the low-temperature studies of protein rely on either low-hydrated samples (essentially, hydrated protein powders), or cryo-protective solutions. Both approaches introduce the hydration environments not characteristic of the protein environments in living systems, which are typically aqueous protein solutions of various concentrations. In this paper, we discuss the coupling between the dynamic components of the protein and its hydration water by critical examining of the existing literature, and then propose that proteins can be studied in an aqueous solution that is remarkably similar in its dynamic properties to pure water, yet does not freeze down to about 200 K, even in the bulk form. The first experiment of this kind using quasielastic neutron scattering is discussed, and more experiments are proposed.

  12. Stomatal structure and physiology do not explain differences in water use among montane eucalypts.

    PubMed

    Gharun, Mana; Turnbull, Tarryn L; Pfautsch, Sebastian; Adams, Mark A

    2015-04-01

    Understanding the regulation of water use at the whole-tree scale is critical to advancing the utility of physiological ecology, for example in its role in predictive hydrology of forested catchments. For three eucalypt species that dominate high-elevation catchments in south-eastern Australia, we examined if whole-tree water use could be related to three widely discussed regulators of water use: stomatal anatomy, sensitivity of stomata [i.e. stomatal conductance (g(s))] to environmental influences, and sapwood area. While daily tree water use varied sixfold among species, sap velocity and sapwood area varied in parallel. Combined, stomatal structure and physiology could not explain differences in species-specific water use. Species which exhibited the fastest (Eucalyptus delegatensis) and slowest (Eucalyptus pauciflora) rates of water use both exhibited greater capacity for physiological control of g(s) [indicated by sensitivity to vapour pressure deficit (VPD)] and a reduced capacity to limit g(s) anatomically [indicated by greater potential g(s) (g(max))]. Conversely, g(s) was insensitive to VPD and g(max) was lowest for Eucalyptus radiata, the species showing intermediate rates of water use. Improved knowledge of stomatal anatomy will help us to understand the capacity of species to regulate leaf-level water loss, but seems likely to remain of limited use for explaining rates of whole-tree water use in montane eucalypts at the catchment scale. PMID:25669453

  13. Bioenergetics and thermal physiology of American water shrews (Sorex palustris).

    PubMed

    Gusztak, R W; Macarthur, R A; Campbell, K L

    2005-02-01

    Rates of O(2) consumption and CO(2) production, telemetered body temperature (T(b)) and activity level were recorded from adult and subadult water shrews (Sorex palustris) over an air temperature (T(a)) range of 3-32 degrees C. Digesta passage rate trials were conducted before metabolic testing to estimate the minimum fasting time required for water shrews to achieve a postabsorptive state. Of the 228 metabolic trials conducted on 15 water shrews, 146 (64%) were discarded because the criteria for inactivity were not met. Abdominal T(b) of S. palustris was independent of T(a) and averaged 38.64 +/- 0.07 degrees C. The thermoneutral zone extended from 21.2 degrees C to at least 32 degrees C. Our estimate of the basal metabolic rate for resting, postabsorptive water shrews (96.88 +/- 2.93 J g(-1) h(-1) or 4.84 +/- 0.14 ml O(2) g(-1) h(-1)) was three times the mass-predicted value, while their minimum thermal conductance in air (0.282 +/- 0.013 ml O(2) g(-1) h(-1)) concurred with allometric predictions. The mean digesta throughput time of water shrews fed mealworms (Tenebrio molitor) or ground meat was 50-55 min. The digestibility coefficients for metabolizable energy (ME) of water shrews fed stickleback minnows (Culaea inconstans) and dragonfly nymphs (Anax spp. and Libellula spp.) were 85.4 +/- 1.3% and 82.8 +/- 1.1%, respectively. The average metabolic rate (AMR) calculated from the gas exchange of six water shrews at 19-22 degrees C (208.0 +/- 17.0 J g(-1) h(-1)) was nearly identical to the estimate of energy intake (202.9 +/- 12.9 J g(-1) h(-1)) measured for these same animals during digestibility trials (20 degrees C). Based on 24-h activity trials and our derived ME coefficients, the minimum daily energy requirement of an adult (14.4 g) water shrew at T(a) = 20 degrees C is 54.0 kJ, or the energetic equivalent of 14.7 stickleback minnows. PMID:15592850

  14. Fog and Rain Water Influences on Tree Physiology and Ecosystem Function in a California Redwood Forest

    NASA Astrophysics Data System (ADS)

    Ewing, H. A.; Weathers, K. C.; Dawson, T. E.; Templer, P. H.; Firestone, M. K.; Elliott, A. M.; Boukili, V. K.

    2008-12-01

    Fog is thought to influence ecological function in coastal forests worldwide, yet few data are available that illuminate the mechanisms underlying this influence. In a California redwood forest we measured water fluxes from horizontally moving fog and vertically delivered rain as well as redwood tree function. The spatial heterogeneity of water fluxes, water availability, tree water use, and water movement varied greatly across seasons. Across the forest as a whole, 98% of water flux to the soil occurred in the rain season and was relatively even across the whole forest. In contrast, below-canopy flux of fog water declined exponentially from the windward edge to the forest interior. Following large fog events, soil moisture was greater at the windward edge than anywhere else in the forest. Physiological activity in redwoods reflected these differences in inputs across seasons: tree physiological responses did not vary spatially in the rain season, but in the fog season, water use was greater, yet water stress was less, in trees at the windward edge of the forest versus the interior. In both seasons, vertical passage through the forest changed the amount of water, revealing the role of both the tree canopy and roots in processing atmospheric inputs. While total fog water inputs were comparatively small, they may have important ecosystem functions, including relief of canopy water stress and, where there is fog drip, functional coupling of above- and below-ground processes.

  15. Demographic, Physiologic and Radiographic Characteristics of COPD Patients Taking Chronic Systemic Corticosteroids

    PubMed Central

    Swift, I.; Satti, A.; Kim, V.; Make, B.J.; Newell, J.; Steiner, R.M.; Wilson, C.; Murphy, J.; Silverman, EK; Criner, G.J.

    2013-01-01

    Long-term therapy with systemic corticosteroids is not recommended in the treatment of chronic obstructive pulmonary disease (COPD). However, experience demonstrates that some patients receive low dose therapy. Our objective was to describe the demographic, physiologic and radiologic characteristics of COPD patients treated with chronic systemic corticosteroids. We analyzed COPD subjects with GOLD I–IV disease in the COPDGene® study. Subjects were divided into two groups based on whether they reported using chronic oral steroids or not. 1264 subjects were included. 58 (4.5%) reported chronic systemic corticosteroid use. There were no differences in age, race, comorbid conditions (other than asthma), or body mass index between the groups. There was a greater proportion of GOLD III (41% vs. 26%) and IV (41% vs. 13%) subjects in the group using chronic systemic corticosteroids. This group used more respiratory medications, required more oxygen (2.31±0.21 vs. 0.59±0.05 L/min; p<0.0001), and walked less distance (245.4±17.4 vs. 367.2±3.9 meters; p<0.0001). They reported more total (1.7±0.16 vs. 0.62±0.03; p<0.0001) and severe exacerbations per year (0.41±0.05 vs. 0.18 ± 0.01; p<0.0001). BODE (5.0±0.3 vs. 2.6±0.1; p<0.0001), MMRC (3.31±0.19 vs. 1.90±0.04; p<0.0001) and SGRQ scores (54.9±2.9 vs 53.3±0.6; p<0.0001) were higher. They also had a higher percentage of emphysema (22.4±1.9 vs. 14.0±0.4; %, p=<0.0001) on CT scan. COPD patients that report using chronic systemic corticosteroids have more severe clinical, physiologic, and radiographic disease. PMID:22292596

  16. Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes.

    PubMed

    Forbes, Scott C; Kennedy, Michael D; Bell, Gordon J

    2013-10-01

    To evaluate the time international canoe polo players spend performing various game activities, measure heart rate (HR) responses during games, and describe the physiological profile of elite players. Eight national canoe polo players were videotaped and wore HR monitors during 3 games at a World Championship and underwent fitness testing. The mean age, height, and weight were 25 ± 1 years, 1.82 ± 0.04 m, and 81.9 ± 10.9 kg, respectively. Time-motion analysis of 3 games indicated that the players spent 29 ± 3% of the game slow and moderate forward paddling, 28 ± 5% contesting, 27 ± 5% resting and gliding, 7 ± 1% turning, 5 ± 1% backward paddling, 2 ± 1% sprinting, and 2 ± 1% dribbling. Sixty-nine (±20)% of the game time was played at an HR intensity above the HR that corresponded to the ventilatory threshold (VT) that was determined during the peak V[Combining Dot Above]O2 test. Peak oxygen uptake and VT were 3.3 ± 0.3 and 2.2 ± 0.3 L·min, respectively, on a modified Monark arm crank ergometer. Arm crank peak 5-second anaerobic power was 379 W. The majority of the time spent during international canoe polo games involved slow-to-moderate forward paddling, contesting for the ball, and resting and gliding. Canoe polo games are played at a high intensity indicated by the HR responses, and the physiological characteristics suggest that these athletes had high levels of upper body aerobic and anaerobic fitness levels. PMID:23287835

  17. Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania

    PubMed Central

    Zongo, P; Chamari, K; Chaouachi, A; Michalak, E; Dellal, A; Castagna, C; Hue, O

    2015-01-01

    This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P = 0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P = 0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P = 0.05. MEL-G height was significantly related to CMJ (r = 0.706, P = 0.01), CMJpeakP (r = 0.709, P = 0.01) and T-Test (r = 0.589, P = 0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P = 0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P = 0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania.

  18. Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania.

    PubMed

    Galy, O; Zongo, P; Chamari, K; Chaouachi, A; Michalak, E; Dellal, A; Castagna, C; Hue, O

    2015-06-01

    This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P = 0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P = 0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P = 0.05. MEL-G height was significantly related to CMJ (r = 0.706, P = 0.01), CMJpeakP (r = 0.709, P = 0.01) and T-Test (r = 0.589, P = 0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P = 0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P = 0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania. PMID:26060337

  19. Physiological, anatomical and leaf hydraulic effects on leaf water ?18O enrichment in different plant species

    NASA Astrophysics Data System (ADS)

    Kahmen, A.; Arndt, S. K.; Dawson, T. E.

    2007-12-01

    Stable oxygen isotope ratios (?18O) of plant and source waters are valuable tools in the analysis of water and carbon fluxes at leaf, plant, and ecosystem scales. Recent improvements in mechanistic models have significantly advanced the understanding of isotopic leaf water enrichment, which is an important source of ?18O variability in plants and ecosystems. However, the marked variability in leaf water ?18O values that have been reported for different plant species hampers efforts to interpret and then apply data on leaf water ?18O values for studies conducted at the ecosystem scale. To improve the understanding and application of ?18O values in leaf water, we tested the interplay of physiological, morphological, anatomical and leaf hydraulic properties as drivers of leaf water ?18O values across 17 Eucalyptus species growing in a common garden. We observed large differences in leaf water ?18O across the 17 species. These differences were only partly driven by physiological and leaf morphological differences across species. A sensitivity analysis using state-of-the-art leaf water enrichment models showed that the parameter - effective path length - (L) is of critical importance for the variability of leaf water ?18O across different species. The data show that L can be related to a suite of leaf properties that include physiology, anatomy and hydraulics. Consequently, consideration of leaf properties will significantly improve the interpretation of ?18O values in leaf water across different plant species and will therefore help in the application of ?18O values in carbon and water cycle assessments at both the plant and the ecosystem scale.

  20. Understanding Beta vulgaris taproot storage characteristics and relationships between biomass, sucrose, betalain and water accumulation using inbred mapping populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Population means for B. vulgaris red beet and sugar beet parental lines are quite variable in their accumulation of sucrose, betalain, water, and biomass. The variability between populations for physiological and yield characteristics is the basis for making a cross and generating an F2-derived F7 M...

  1. Identification of Physiological Traits for Early Detecting Water Deficit Stress in Sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane (Saccharum spp.) genotype selection has been more successful for organic (muck) than sand soils in Florida. Water deficit stress during its formative growth phase may limit sugarcane growth and yields on Florida sand soils. Therefore, identifying proper physiological traits will help scien...

  2. Physiological Response of Rainbow Trout to Sediment Released during Open-Cut Pipeline Water Crossing Construction

    Microsoft Academic Search

    SCOTT M. REID; GLENN ISAAC; SERGE METIKOSH; JIM EVANS

    2003-01-01

    The physiological response of rainbow trout exposed to elevated suspended sediment concentrations downstream of two open-cut pipeline water crossings was investigated. Trout held in cages downstream of construction had increased respiration rates and shorter times till loss of equilibrium during sealed jar bioassays. Differences in blood hematocrit levels between experiments and transects is attributed to sediment concentration and particle size.

  3. Salicylic acid-induced physiological and biochemical changes in lemongrass varieties under water stress

    Microsoft Academic Search

    Mohd Idrees; M. Masroor A. Khan; Tariq Aftab; M. Naeem; Nadeem Hashmi

    2010-01-01

    Salicylic acid (SA) treatment reduces the damaging action by water deficit on growth and accelerates a restoration of growth processes. The aim of the present work was to study the physiological and biochemical alteration induced by SA in lemongrass plants under stress conditions. Therefore, a pot culture experiment was conducted to test whether SA application at concentration of (10 M)

  4. Genotypic differences in architectural and physiological responses to water restriction in rose bush

    PubMed Central

    Li-Marchetti, Camille; Le Bras, Camille; Relion, Daniel; Citerne, Sylvie; Huché-Thélier, Lydie; Sakr, Soulaiman; Morel, Philippe; Crespel, Laurent

    2015-01-01

    The shape and, therefore, the architecture of the plant are dependent on genetic and environmental factors such as water supply. The architecture determines the visual quality, a key criterion underlying the decision to purchase an ornamental potted plant. The aim of this study was to analyze genotypic responses of eight rose bush cultivars to alternation of water restriction and re-watering periods, with soil water potential of -20 and -10 kPa respectively. Responses were evaluated at the architectural level through 3D digitalization using six architectural variables and at the physiological level by measuring stomatal conductance, water content, hormones [abscisic acid (ABA), auxin, cytokinins, jasmonic acid, and salicylic acid (SA)], sugars (sucrose, fructose, and glucose), and proline. Highly significant genotype and watering effects were revealed for all the architectural variables measured, as well as genotype × watering interaction, with three distinct genotypic architectural responses to water restriction – weak, moderate and strong – represented by Hw336, ‘Baipome’ and ‘The Fairy,’ respectively. The physiological analysis explained, at least in part, the more moderate architectural response of ‘Baipome’ compared to ‘The Fairy,’ but not that of Hw336 which is an interspecific hybrid. Such physiological responses in ‘Baipome’ could be related to: (i) the maintenance of the stimulation of budbreak and photosynthetic activity during water restriction periods due to a higher concentration in conjugated cytokinins (cCK) and to a lower concentration in SA; (ii) a better resumption of budbreak during the re-watering periods due to a lower concentration in ABA during this period. When associated with the six architectural descriptors, cCK, SA and ABA, which explained the genotypic differences in this study, could be used as selection criteria for breeding programs aimed at improving plant shape and tolerance to water restriction. PMID:26074929

  5. [Impacts of salt stress on the growth and physiological characteristics of Panicum virgatum seedlings].

    PubMed

    Fan, Xi-Feng; Hou, Xin-Cun; Zhu, Yi; Wu, Ju-Ying

    2012-06-01

    An experiment was conducted in an artificial climate chamber to study the growth and physiological characteristics of switchgrass (Panicum virgatum) seedlings exposed to 0, 50, 100, 150, and 200 mmol x L(-1) of NaCl solutions. With the increasing concentration of the NaCl, the seedling growth was obviously inhibited. The plant height decreased, leaves became smaller, photosynthetic leaf area and net photosynthetic rate reduced, and dry matter accumulation decreased significantly, presenting the general traits of glycophyte. Meanwhile, the seedlings also showed relatively high salt tolerance. After exposed to 200 mmol x L(-1) of NaCl for 30 days, the seedlings still survived, with the green leaf area per plant and net photosynthetic rate being 491.9 cm2 and 0.93 micromol CO2 x m(-2) x s(-1), respectively. In this experiment, the salt tolerance threshold for P. virgatum was 178.6 mmol L(-1) when taking 50% drop in biomass as the standard. PMID:22937633

  6. Pullulan production and physiological characteristics of Aureobasidium pullulans under acid stress.

    PubMed

    Wang, Dahui; Yu, Xiaoliu; Gongyuan, Wei

    2013-09-01

    In this study, batch processes of pullulan production by Aureobasidium pullulans CCTCC M 2012259 under different pH environments were evaluated. The pH of the medium decreased quickly to an acid stress condition under batch fermentation without pH control. A higher pullulan production was always obtained with a lower biomass under a given glucose concentration with constant pH control, and vice versa. Based on the nonlinear regression analysis of the results obtained from diverse pH control modes, a constant controlled pH of 3.8 was predicted as an optimum pH for efficient pullulan production using a one-element cubic equation. A maximum pullulan concentration of 26.8 g/L and a minimum biomass of 8.1 g/L were achieved under the optimal pH of 3.8, which were in good agreement with the results predicted by the mathematical model. Further information on the physiological characteristics of A. pullulans CCTCC M 2012259 such as intracellular pH, NADH/NAD(+), ATP/ADP, and glutathione generation under moderate or severe acidic conditions were investigated, and the results presented more evidence on why pullulan biosynthesized with high efficiency under moderate acid stress (e.g., pH 3.8), which would also help us to better understand the response of the cells to acid stress. PMID:23868298

  7. Physiological characteristics of the extreme thermophile Caldicellulosiruptor saccharolyticus: an efficient hydrogen cell factory.

    PubMed

    Willquist, Karin; Zeidan, Ahmad A; van Niel, Ed W J

    2010-01-01

    Global concerns about climate changes and their association with the use of fossil fuels have accelerated research on biological fuel production. Biological hydrogen production from hemicellulose-containing waste is considered one of the promising avenues. A major economical issue for such a process, however, is the low substrate conversion efficiency. Interestingly, the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus can produce hydrogen from carbohydrate-rich substrates at yields close to the theoretical maximum of the dark fermentation process (i.e., 4 mol H2/mol hexose). The organism is able to ferment an array of mono-, di- and polysaccharides, and is relatively tolerant to high partial hydrogen pressures, making it a promising candidate for exploitation in a biohydrogen process. The behaviour of this Gram-positive bacterium bears all hallmarks of being adapted to an environment sparse in free sugars, which is further reflected in its low volumetric hydrogen productivity and low osmotolerance. These two properties need to be improved by at least a factor of 10 and 5, respectively, for a cost-effective industrial process. In this review, the physiological characteristics of C. saccharolyticus are analyzed in view of the requirements for an efficient hydrogen cell factory. A special emphasis is put on the tight regulation of hydrogen production in C. saccharolyticus by both redox and energy metabolism. Suggestions for strategies to overcome the current challenges facing the potential use of the organism in hydrogen production are also discussed. PMID:21092203

  8. Physiological characteristics of the extreme thermophile Caldicellulosiruptor saccharolyticus: an efficient hydrogen cell factory

    PubMed Central

    2010-01-01

    Global concerns about climate changes and their association with the use of fossil fuels have accelerated research on biological fuel production. Biological hydrogen production from hemicellulose-containing waste is considered one of the promising avenues. A major economical issue for such a process, however, is the low substrate conversion efficiency. Interestingly, the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus can produce hydrogen from carbohydrate-rich substrates at yields close to the theoretical maximum of the dark fermentation process (i.e., 4 mol H2/mol hexose). The organism is able to ferment an array of mono-, di- and polysaccharides, and is relatively tolerant to high partial hydrogen pressures, making it a promising candidate for exploitation in a biohydrogen process. The behaviour of this Gram-positive bacterium bears all hallmarks of being adapted to an environment sparse in free sugars, which is further reflected in its low volumetric hydrogen productivity and low osmotolerance. These two properties need to be improved by at least a factor of 10 and 5, respectively, for a cost-effective industrial process. In this review, the physiological characteristics of C. saccharolyticus are analyzed in view of the requirements for an efficient hydrogen cell factory. A special emphasis is put on the tight regulation of hydrogen production in C. saccharolyticus by both redox and energy metabolism. Suggestions for strategies to overcome the current challenges facing the potential use of the organism in hydrogen production are also discussed. PMID:21092203

  9. Improvement of Physiological Characteristic of Selenium-Enriched Candida utilis with Amino Acids Addition.

    PubMed

    Xiaoguang, Ge; Dahui, Wang; Gongyuan, Wei; Min, Nie; Na, Shao

    2011-01-01

    The effects of amino acids addition on cell growth, glutathione biosynthesis, glutathione distribution, and the intracellular oxidation-reduction environment of Candida utilis SZU 07-01 during selenium enrichment were investigated in this study. Most amino acids under appropriate concentrations have positive effects on cell growth of the yeast strain, except for phenylalanine and proline, compared with the control without amino acid addition. The bioconversion of selenite to organic selenium induced the reduction of glutathione synthesis and intracellular distribution of glutathione. However, amino acids including cysteine, glutamine, glutamic acid, isoleucine, leucine, and tyrosine could effectively promote the selenium-enriched yeast to elevate glutathione production, especially increasing the intracellular glutathione content. Moreover, addition of these six different amino acids apparently decreased malondialdehyde concentration and recovered the normal intracellular redox environment of the selenium-enriched C. utilis SZU 07-01. The improvement of physiological characteristic of the selenium-enriched yeast by increasing intracellular glutathione content and lowering malondialdehyde content will undoubtedly help to widen application of selenium-enriched yeast as food or feed additives. PMID:21350658

  10. Soil-Water Characteristic Curve Modeling at Low Water Content: Empirical and Semi-Empirical Approaches

    E-print Network

    Paris-Sud XI, Université de

    Soil-Water Characteristic Curve Modeling at Low Water Content: Empirical and Semi model, the Modified Kovacs (MK) model for the determination of soil-water characteristic curve at the low water contents of two horizons of a soil from Burkina Faso. Combining terms from capillary state

  11. Boxelder water sources and physiology at perennial and ephemeral stream sites in Arizona

    Microsoft Academic Search

    THOMAS E. KOLB; STEPHEN C. HART; RONALD AMUNDSON

    Summary To assess the influence of stream water on leaf gas exchange and water potential in different sized boxelder trees (Acer negundo L.), we compared these characteristics in trees growing beside a perennial stream and a nearby ephemeral stream in a montane--riparian forest in northern Arizona. Pat- terns of tree water use were quantified by stable isotope analy- sis (?

  12. Physical and Physiological Characteristics of Elite Male Handball Players from Teams with a Different Ranking

    PubMed Central

    Nikolaidis, Pantelis T.; Ingebrigtsen, Jørgen

    2013-01-01

    The aim of this study was to examine possible discriminant physical and physiological characteristics between elite male handball players from elite teams with different league rankings. Players from three teams (A, B and C), which competed in the first league of the Greek championship during the season 2011–2012 participated in the study. Team A finished first, B came second and C came eighth out of eleven clubs. Teams A and B also participated in European Cups, and team A won the European Challenge Cup. The players (n=44) were examined for anthropometric characteristics and performed a series of physical fitness tests. Players from teams A and B were taller (6.2 cm (0.7;11.7), mean difference (95% CI) and 9.2 cm (4.0;14.5), respectively), and had a higher amount of fat free mass (6.4 kg (1.1;11.8) and 5.4 kg (0.2;10.5)) compared to those of team C. Players from team A performed better than players from team C in the squat jump (5.5 cm (1.0;10.0)), the countermovement jump without (5.5 cm (0.4;10.6)) and with arm-swing (6.0 cm (0.7;11.3)) and in the 30 s Bosco test (5.7 W·kg?1 (1.2;10.2)). Also, players from team A outperformed team B in mean power during the Wingate anaerobic test (WAnT, 0.5 W·kg?1(0;0.9)) and in the Bosco test (7.8 W·kg?1 (3.4;12.2)). Overall, players from the best ranked team performed better than the lowest ranked team on WAnT, vertical jumps and the Bosco test. Stepwise discriminant analysis showed that stature and mean power during the Bosco test were the most important characteristics in TH players, accounting for 54.6% of the variance in team ranking. These findings indicate the contribution of particular physical fitness components (stature, fat free mass and anaerobic power) to excellence in TH. In addition, the use of the Bosco test as an assessment tool in talent identification and physical fitness monitoring in this sport is further recommended. PMID:24235989

  13. Physiological, anatomical and transcriptional alterations in a rice mutant leading to enhanced water stress tolerance

    PubMed Central

    Lima, John Milton; Nath, Manoj; Dokku, Prasad; Raman, K. V.; Kulkarni, K. P.; Vishwakarma, C.; Sahoo, S. P.; Mohapatra, U. B.; Mithra, S. V. Amitha; Chinnusamy, V.; Robin, S.; Sarla, N.; Seshashayee, M.; Singh, K.; Singh, A. K.; Singh, N. K.; Sharma, R. P.; Mohapatra, T.

    2015-01-01

    Water stress is one of the most severe constraints to crop productivity. Plants display a variety of physiological and biochemical responses both at the cellular and whole organism level upon sensing water stress. Leaf rolling, stomatal closure, deeper root penetration, higher relative water content (RWC) and better osmotic adjustment are some of the mechanisms that plants employ to overcome water stress. In the current study, we report a mutant, enhanced water stress tolerant1 (ewst1) with enhanced water stress tolerance, identified from the ethyl methanesulfonate-induced mutant population of rice variety Nagina22 by field screening followed by withdrawal of irrigation in pots and hydroponics (PEG 6000). Though ewst1 was morphologically similar to the wild type (WT) for 35 of the 38 morphological descriptors (except chalky endosperm/expression of white core, decorticated grain colour and grain weight), it showed enhanced germination in polyethylene glycol-infused medium. It exhibited increase in maximum root length without any significant changes in its root weight, root volume and total root number on crown when compared with the WT under stress in PVC tube experiment. It also showed better performance for various physiological parameters such as RWC, cell membrane stability and chlorophyll concentration upon water stress in a pot experiment. Root anatomy and stomatal microscopic studies revealed changes in the number of xylem and phloem cells, size of central meta-xylem and number of closed stomata in ewst1. Comparative genome-wide transcriptome analysis identified genes related to exocytosis, secondary metabolites, tryptophan biosynthesis, protein phosphorylation and other signalling pathways to be playing a role in enhanced response to water stress in ewst1. The possible involvement of a candidate gene with respect to the observed morpho-physiological and transcriptional changes and its role in stress tolerance are discussed. The mutant identified and characterized in this study will be useful for further dissection of water stress tolerance in rice. PMID:25818072

  14. Physiological, anatomical and transcriptional alterations in a rice mutant leading to enhanced water stress tolerance.

    PubMed

    Lima, John Milton; Nath, Manoj; Dokku, Prasad; Raman, K V; Kulkarni, K P; Vishwakarma, C; Sahoo, S P; Mohapatra, U B; Mithra, S V Amitha; Chinnusamy, V; Robin, S; Sarla, N; Seshashayee, M; Singh, K; Singh, A K; Singh, N K; Sharma, R P; Mohapatra, T

    2015-01-01

    Water stress is one of the most severe constraints to crop productivity. Plants display a variety of physiological and biochemical responses both at the cellular and whole organism level upon sensing water stress. Leaf rolling, stomatal closure, deeper root penetration, higher relative water content (RWC) and better osmotic adjustment are some of the mechanisms that plants employ to overcome water stress. In the current study, we report a mutant, enhanced water stress tolerant1 (ewst1) with enhanced water stress tolerance, identified from the ethyl methanesulfonate-induced mutant population of rice variety Nagina22 by field screening followed by withdrawal of irrigation in pots and hydroponics (PEG 6000). Though ewst1 was morphologically similar to the wild type (WT) for 35 of the 38 morphological descriptors (except chalky endosperm/expression of white core, decorticated grain colour and grain weight), it showed enhanced germination in polyethylene glycol-infused medium. It exhibited increase in maximum root length without any significant changes in its root weight, root volume and total root number on crown when compared with the WT under stress in PVC tube experiment. It also showed better performance for various physiological parameters such as RWC, cell membrane stability and chlorophyll concentration upon water stress in a pot experiment. Root anatomy and stomatal microscopic studies revealed changes in the number of xylem and phloem cells, size of central meta-xylem and number of closed stomata in ewst1. Comparative genome-wide transcriptome analysis identified genes related to exocytosis, secondary metabolites, tryptophan biosynthesis, protein phosphorylation and other signalling pathways to be playing a role in enhanced response to water stress in ewst1. The possible involvement of a candidate gene with respect to the observed morpho-physiological and transcriptional changes and its role in stress tolerance are discussed. The mutant identified and characterized in this study will be useful for further dissection of water stress tolerance in rice. PMID:25818072

  15. Physiological and growth responses to water deficit in the bioenergy crop Miscanthus x giganteus

    PubMed Central

    Ings, Jennifer; Mur, Luis A. J.; Robson, Paul R. H.; Bosch, Maurice

    2013-01-01

    High yielding perennial biomass crops of the species Miscanthus are widely recognized as one of the most promising lignocellulosic feedstocks for the production of bioenergy and bioproducts. Miscanthus is a C4 grass and thus has relatively high water use efficiency. Cultivated Miscanthus comprises primarily of a single clone, Miscanthus x giganteus, a sterile hybrid between M. sacchariflorus and M. sinensis. M. x giganteus is high yielding and expresses desirable combinations of many traits present in the two parental species types; however, it responds poorly to low water availability. To identify the physiological basis of the response to water stress in M. x giganteus and to identify potential targets for breeding improvements we characterized the physiological responses to water-deficit stress in a pot experiment. The experiment has provided valuable insights into the temporal aspects of drought-induced responses of M. x giganteus. Withholding water resulted in marked changes in plant physiology with growth-associated traits among the first affected, the most rapid response being a decline in the rate of stem elongation. A reduction in photosynthetic performance was among the second set of changes observed; indicated by a decrease in stomatal conductance followed by decreases in chlorophyll fluorescence and chlorophyll content. Measures reflecting the plant water status were among the last affected by the drought treatment. Metabolite analysis indicated that proline was a drought stress marker in M. x giganteus, metabolites in the proline synthesis pathway were more abundant when stomatal conductance decreased and dry weight accumulation ceased. The outcomes of this study in terms of drought-induced physiological changes, accompanied by a proof-of-concept metabolomics investigation, provide a platform for identifying targets for improved drought-tolerance of the Miscanthus bioenergy crop. PMID:24324474

  16. Growth and Physiological Responses to Water Depths in Carex schmidtii Meinsh.

    PubMed

    Yan, Hong; Liu, Ruiquan; Liu, Zinan; Wang, Xue; Luo, Wenbo; Sheng, Lianxi

    2015-01-01

    A greenhouse experiment was performed to investigate growth and physiological responses to water depth in completely submerged condition of a wetland plant Carex schmidtii Meinsh., one of the dominant species in the Longwan Crater Lake wetlands (China). Growth and physiological responses of C. schmidtii were investigated by growing under control (non-submerged) and three submerged conditions (5 cm, 15 cm and 25 cm water level). Total biomass was highest in control, intermediate in 5 cm treatment and lowest in the other two submerged treatments. Water depth prominently affected the first-order lateral root to main root mass ratio. Alcohol dehydrogenase (ADH) activity decreased but malondialdehyde (MDA) content increased as water depth increased. The starch contents showed no differences among the various treatments at the end of the experiment. However, soluble sugar contents were highest in control, intermediate in 5 cm and 15 cm treatments and lowest in 25 cm treatment. Our data suggest that submergence depth affected some aspects of growth and physiology of C. schmidtii, which can reduce anoxia damage not only through maintaining the non-elongation strategy in shoot part but also by adjusting biomass allocation to different root orders rather than adjusting root-shoot biomass allocation. PMID:26009895

  17. Growth and Physiological Responses to Water Depths in Carex schmidtii Meinsh

    PubMed Central

    Yan, Hong; Liu, Ruiquan; Liu, Zinan; Wang, Xue; Luo, Wenbo; Sheng, Lianxi

    2015-01-01

    A greenhouse experiment was performed to investigate growth and physiological responses to water depth in completely submerged condition of a wetland plant Carex schmidtii Meinsh., one of the dominant species in the Longwan Crater Lake wetlands (China). Growth and physiological responses of C. schmidtii were investigated by growing under control (non-submerged) and three submerged conditions (5 cm, 15 cm and 25 cm water level). Total biomass was highest in control, intermediate in 5 cm treatment and lowest in the other two submerged treatments. Water depth prominently affected the first-order lateral root to main root mass ratio. Alcohol dehydrogenase (ADH) activity decreased but malondialdehyde (MDA) content increased as water depth increased. The starch contents showed no differences among the various treatments at the end of the experiment. However, soluble sugar contents were highest in control, intermediate in 5 cm and 15 cm treatments and lowest in 25 cm treatment. Our data suggest that submergence depth affected some aspects of growth and physiology of C. schmidtii, which can reduce anoxia damage not only through maintaining the non-elongation strategy in shoot part but also by adjusting biomass allocation to different root orders rather than adjusting root-shoot biomass allocation. PMID:26009895

  18. Study on the relationship between the winter wheat thermal infrared image characteristics and physiological indicators

    NASA Astrophysics Data System (ADS)

    Chen, Zi-long; Ren, Xiang-rong; Cong, Hua; Wang, Cheng; Zhu, Da-zhou

    2014-11-01

    Arid directly affects crop growth and yield, such as reduces photosynthesis, weakens respiration rate, slows down the material transport, disorders stomatal switch, blocks the synthesis of chlorophyll, affects the cell wall and protein synthesis, etc., eventually leads to the reduction of output. How to solve this problem? This paper proposes a drought index based on thermal imaging technology. Canopy temperature distribution can reflect the growth of crops. And using thermal imaging technology can access to crop canopy temperature distribution quickly. Physiological indexes such as the changes of stomatal conductance and chlorophyll content is the important basis of crop drought resistance identification.So this paper studied the distribution of wheat canopy temperature with the change of stomatal conductance and chlorophyll content under drought conditions. The study was based on different drought resistant genotypes of winter wheat in Xinjiang with German JENOPTIK portable infrared thermal imager for canopy temperature information. The canopy leaf stomatal conductance and chlorophyll content was measured by SC-1 porosity meter and SPAD chlorophyll meter. Results prove that winter wheat canopy temperature decreases with the increase of stomatal conductance in dry conditions, which has a good linear relationship (r=-0.67). The correlation of canopy temperature and stomatal conductance of poor drought resistance(-0.93) is greater than that of good one(-0.46). There is significant difference between stomatal conductance and chlorophyll content of different drought resistance varieties(P<0.05). The variety of poor drought resistance is greater that of good one in morning-afternoon stomatal conductance change. And the chlorophyll content of the variety of good drought resistance is greater that of poor one. The conclusions above show that canopy temperature distribution has good correlation with the crop drought resistance indexes and can be used as an early indicator of drought resistance identification.This conclusion has important significance for drought resistance identification, the reasonable irrigation guidance and improving the water use efficiency.

  19. Physiologic responses to water immersion in man: A compendium of research

    NASA Technical Reports Server (NTRS)

    Kollias, J.; Vanderveer, D.; Dorchak, K. J.; Greenleaf, J. E.

    1976-01-01

    A total of 221 reports published through December 1973 in the area of physiologic responses to water immersion in man were summarized. The author's abstract or summary was used whenever possible. Otherwise, a detailed annotation was provided under the subheadings: (1) purpose, (2) procedures and methods, (3) results, and (4) conclusions. The annotations are in alphabetical order by first author; author and subject indexes are included. Additional references are provided in the selected bibliography.

  20. Morphological and physiological variation in western redcedar ( Thuja plicata ) populations under contrasting soil water conditions

    Microsoft Academic Search

    Shihe Fan; Steven C. Grossnickle; John H. Russell

    2008-01-01

    Adaptation to precipitation conditions may induce genetic diversity that changes morphological and physiological traits. This\\u000a hypothesis was investigated in the seedlings of seven western redcedar (Thuja plicata Donn ex D. Don) populations, which were collected along a precipitation transect from the Pacific coast to the southern interior\\u000a of British Columbia, Canada. The experimental seedlings were either well-watered or soil-droughted and

  1. Assessing physiological responses of dune forest functional groups to changing water availability: from Tropics to Mediterranean.

    NASA Astrophysics Data System (ADS)

    Antunes, Cristina; Lo Cascio, Mauro; Correia, Otília; Vieira, Simone; Cruz Diaz Barradas, Maria; Zunzunegui, Maria; Ramos, Margarida; João Pereira, Maria; Máguas, Cristina

    2014-05-01

    Alterations in water availability are important to vegetation as can produce dramatic changes in plant communities, on physiological performance or survival of plant species. Particularly, groundwater lowering and surface water diversions will affect vulnerable coastal dune forests, ecosystems particularly sensitive to groundwater limitation. Reduction of water tables can prevent the plants from having access to one of their key water sources and inevitably affect groundwater-dependent species. The additional impact of drought due to climatic change on groundwater-dependent ecosystems has become of increasing concern since it aggravates groundwater reduction impacts with consequent uncertainties about how vegetation will respond over the short and long term. Sand dune plant communities encompass a diverse number of species that differ widely in root depth, tolerance to drought and capacity to shift between seasonal varying water sources. Plant functional groups may be affected by water distribution and availability differently. The high ecological diversity of sand dune forests, characterized by sandy soils, well or poorly drained, poor in nutrients and with different levels of salinity, can occur in different climatic regions of the globe. Such is the case of Tropical, Meso-mediterranean and Mediterranean areas, where future climate change is predicted to change water availability. Analyses of the relative natural abundances of stable isotopes of carbon (13C/12C) and oxygen (18O/16O) have been used across a wide range of scales, contributing to our understanding of plant ecology and interactions. This approach can show important temporal and spatial changes in utilization of different water sources by vegetation. Accordingly, the core idea of this work is to evaluate, along a climatic gradient, the responses and capacity of different coastal plant communities to adapt to changing water availability. This large-climatic-scale study, covering Brazil, Portugal and Spain, provide an excellent experimental network to study the water dynamics and community functioning in natural ecosystems of high ecological value. To fulfill the main objective, a stable isotope approach (leaf ?13C and xylem+water sources ?18O) was used as a tool to assess physiological performance and water strategies integrated in spatio-temporal water dynamics. Plant functional groups' water use was characterized in a water changing situation (at different seasons) in a climatic gradient. We evaluated stress sensitivity of the functional groups to seasonal changes in water availability in different communities and tried to understand their water use strategy.

  2. PERFORMANCE CHARACTERISTICS OF PACKAGE WATER TREATMENT PLANTS

    EPA Science Inventory

    This study was undertaken to collect reliable onsite information on the quality of treated water produced by package plants. Six plants in operation year around were selected to be representative of those serving small populations and were monitored to assess their performance. P...

  3. Spectral reflectance and radiance characteristics of water pollutants

    NASA Technical Reports Server (NTRS)

    Wezernak, C. T.; Turner, R. E.; Lyzenga, D. R.

    1976-01-01

    Spectral reflectance characteristics of water pollutants and water bodies were compiled using the existing literature. Radiance calculations were performed at satellite altitude for selected illumination angles and atmospheric conditions. The work described in this report was limited to the reflective portion of the spectrum between 0.40 micrometer to 1.0 micrometer.

  4. Coal-water slurry atomization characteristics

    SciTech Connect

    Caton, J.A.; Kihm, K.D.

    1994-04-01

    The overall objective of this work was to fully characterize the CWS fuel sprays of a medium-speed diesel engine injection system. Specifically, the spray plume penetration as a function of time was determined for a positive-displacement fuel injection system. The penetration was determined as a function of orifice diameter, coal loading, gas density in the engine, and fuel line pressure. Preliminary droplet information also was obtained. The results of this study will assist CWS engine development by providing much needed insight about the fuel spray. In addition, the results will aid the development and use of CWS engine cycle simulations which require information on the fuel spray characteristics.

  5. Lead tolerance of water hyacinth (Eichhornia crassipes Mart. - Pontederiaceae) as defined by anatomical and physiological traits.

    PubMed

    Pereira, Fabricio J; Castro, Evaristo M de; Oliveira, Cynthia de; Pires, Marinês F; Pereira, Marcio P; Ramos, Silvio J; Faquin, Valdemar

    2014-09-01

    This study aimed at verifying the lead tolerance of water hyacinth and at looking at consequent anatomical and physiological modifications. Water hyacinth plants were grown on nutrient solutions with five different lead concentrations: 0.00, 0.50, 1.00, 2.00 and 4.00 mg L-1 by 20 days. Photosynthesis, transpiration, stomatal conductance and the Ci/Ca rate were measured at the end of 15 days of experiment. At the end of the experiment, the anatomical modifications in the roots and leaves, and the activity of antioxidant system enzymes, were evaluated. Photosynthetic and Ci/Ca rates were both increased under all lead treatments. Leaf anatomy did not exhibit any evidence of toxicity effects, but showed modifications of the stomata and in the thickness of the palisade and spongy parenchyma in the presence of lead. Likewise, root anatomy did not exhibit any toxicity effects, but the xylem and phloem exhibited favorable modifications as well as increased apoplastic barriers. All antioxidant system enzymes exhibited increased activity in the leaves, and some modifications in roots, in the presence of lead. It is likely, therefore, that water hyacinth tolerance to lead is related to anatomical and physiological modifications such as increased photosynthesis and enhanced anatomical capacity for CO2 assimilation and water conductance. PMID:25211112

  6. Effects of nitrogen dioxide on biochemical and physiological characteristics of soybean (Glycine max (L. ) Merrill)

    SciTech Connect

    Sabaratnam, S.

    1987-01-01

    One month old soybean cv. Williams plants were exposed to nitrogen dioxide (NO/sub 2/ at 0.1, 0.2, 0.3, and 0.5 ppm) and carbon-filtered air (control), 7 hour per day, for 5 days, under controlled environment. Data were collected on net photosynthetic rate (PN), stomatal resistance (SR), and dark respiratory rate (DR), immediately following fifth day of exposure and 24 hours after termination of exposure using LICOR 6000 Portable Photosynthesis System. Chlorophyll a (Ch a), chlorophyll b (Ch b), and total chlorophyll (tot Ch) were measured before and after exposures, using a spectrophotometer. Leaf nitrogen was determined using kjeldahl digestion followed by colorimetric determination of total N. Growth characteristics-relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), and root shoot ratio (RSR)-were computed for treated plants using standard growth equations. Solute leakage (electrical conductivity) was measured 2 and 24 hours after incubation of treated leaf tissue in deionized water.

  7. Green Roof Water Harvesting and Recycling Effects on Soil and Water Chemistry and Plant Physiology 

    E-print Network

    Laminack, Kirk Dickison

    2014-04-17

    on each green roof. Plant water potential, specific leaf area and rates of photosynthesis, transpiration, and conductivity were not significantly different between roofs which helped to further conclude that water quality parameters remained within...

  8. THE EFFECT OF TABEX AND LACTOFOL ON SOME PHYSIOLOGICAL CHARACTERISTICS OF ORIENTAL TOBACCO

    Microsoft Academic Search

    Stoyan Pandev

    1997-01-01

    Summary. The effect of monoethyl adipinic acid ester (MEEAdA - tabex) and of the leaf suspension fertilizer lactrofol on some physiological charac- teristics of oriental tobacco was studied in relation with mineral nutrition. It was found that treatment with tabex, lactofol and their combination of plants grown on the available soil supply with unbalanced nutrients (unfertilized) increased chlorophyll a and

  9. Cardiovascular risk factors for hypertension: The contribution of physiological, behavioral, and psychological characteristics

    Microsoft Academic Search

    Rachel Mara Copen

    1997-01-01

    The contribution of physiological, behavioral, and psychological risk factors for hypertension as relates to resting blood pressure were examined with hierarchical multiple regressions in 124 normotensive and mildly hypertensive black and white males and females. Casual systolic and diastolic blood pressure were assessed based on multiple readings averaged from two days of the study.Variables consistently showing the expected positive association

  10. [Dermal glands of water mites (Acariformes: Parasitengona: Hydrachnidia) and their possible eco-physiological significance].

    PubMed

    Shatrov, A B

    2013-01-01

    Functional and comparative morphology is the basis for investigation of animal kingdom, its diversity and possible evolution. Moreover, it is extremely valuable in understanding of functioning of the living systems in unity of their organ and tissue structures. In the present paper, the organization of dermal glands and their possible eco-physiological role in the life of adult water mites are analyzed on the basis of the available data and original investigations from the point of view of fundamental functional-morphological approaches in the study of various groups of arthropods developed by Prof. Yu.S. Balashov. PMID:24455907

  11. Rootstock alleviates PEG-induced water stress in grafted pepper seedlings: physiological responses.

    PubMed

    Penella, Consuelo; Nebauer, Sergio G; Bautista, Alberto San; López-Galarza, Salvador; Calatayud, Ángeles

    2014-06-15

    Recent studies have shown that tolerance to abiotic stress, including water stress, is improved by grafting. In a previous work, we took advantage of the natural variability of Capsicum spp. and selected accessions tolerant and sensitive to water stress as rootstocks. The behavior of commercial cultivar 'Verset' seedlings grafted onto the selected rootstocks at two levels of water stress provoked by adding 3.5 and 7% PEG (polyethylene glycol) was examined over 14 days. The objective was to identify the physiological traits responsible for the tolerance provided by the rootstock in order to determine if the tolerance is based on the maintenance of the water relations under water stress or through the activation of protective mechanisms. To achieve this goal, various physiological parameters were measured, including: water relations; proline accumulation; gas exchange; chlorophyll fluorescence; nitrate reductase activity; and antioxidant capacity. Our results indicate that the effect of water stress on the measured parameters depends on the duration and intensity of the stress level, as well as the rootstock used. Under control conditions (0% PEG) all plant combinations showed similar values for all measured parameters. In general terms, PEG provoked a strong decrease in the gas exchange parameters in the cultivar grafted onto the sensitive accessions, as also observed in the ungrafted plants. This effect was related to lower relative water content in the plants, provoked by an inefficient osmotic adjustment that was dependent on reduced proline accumulation. At the end of the experiment, chronic photoinhibition was observed in these plants. However, the plants grafted onto the tolerant rootstocks, despite the reduction in photosynthetic rate, maintained the protective capacity of the photosynthetic machinery mediated by osmotic adjustment (based on higher proline content). In addition, water stress limited uptake and further NO3(-) transfer to the leaves. Increased nitrate reductase activity in the roots was observed, mainly in plants grafted onto the sensitive rootstocks, as well as the ungrafted plants, and this was associated with the lessened flux to the leaves. This study suggests that PEG-induced water stress can be partially alleviated by using tolerant accessions as rootstocks. PMID:24877676

  12. Anthropomorphic breast phantoms with physiological water, lipid, and hemoglobin content for near-infrared spectral tomography

    PubMed Central

    Michaelsen, Kelly E.; Krishnaswamy, Venkataramanan; Shenoy, Adele; Jordan, Emily; Pogue, Brian W.; Paulsen, Keith D.

    2014-01-01

    Abstract. Breast mimicking tissue optical phantoms with sufficient structural integrity to be deployed as stand-alone imaging targets are developed and successfully constructed with biologically relevant concentrations of water, lipid, and blood. The results show excellent material homogeneity and reproducibility with inter- and intraphantom variability of 3.5 and 3.8%, respectively, for water and lipid concentrations ranging from 15 to 85%. The phantoms were long-lasting and exhibited water and lipid fractions that were consistent to within 5% of their original content when measured 2 weeks after creation. A breast-shaped three-compartment model of adipose, fibroglandular, and malignant tissues was created with water content ranging from 30% for the adipose simulant to 80% for the tumor. Mean measured water content ranged from 30% in simulated adipose to 73% in simulated tumor with the higher water localized to the tumor-like material. This novel heterogeneous phantom design is composed of physiologically relevant concentrations of the major optical absorbers in the breast in the near-infrared wavelengths that should significantly improve imaging system characterization and optimization because the materials have stand-alone structural integrity and can be readily molded into the sizes and shapes of tissues commensurate with clinical breast imaging. PMID:24549438

  13. Dynamic analysis of Lactobacillus delbrueckii subsp. bulgaricus CFL1 physiological characteristics during fermentation

    Microsoft Academic Search

    Aline Rault; Marielle Bouix; Catherine Béal

    2008-01-01

    This study aimed at examining and comparing the relevance of various methods in order to discriminate different cellular states\\u000a of Lactobacillus bulgaricus CFL1 and to improve knowledge on the dynamics of the cellular physiological state during growth and acidification. By using\\u000a four fluorescent probes combined with multiparametric flow cytometry, membrane integrity, intracellular esterase activity,\\u000a cellular vitality, membrane depolarization, and intracellular

  14. [Effects of grafting on physiological characteristics of melon (Cucumis melo) seedlings under copper stress].

    PubMed

    Tan, Ming-min; Zhang, Xin-ying; Fu, Qiu-shi; He, Zhong-qun; Wang, Huai-song

    2014-12-01

    The effects of grafting on physiological characters of melon (Cucumis melo) seedlings under copper stress were investigated with Pumpkin Jingxinzhen No. 3 as stock and oriental melon IVF09 as scion. The results showed that the physiological characters of melon seedlings were inhibited significantly under copper stress. Compared with self-rooted seedlings, the biomass, the contents of photosynthetic pigment, glucose and fructose, the photosynthetic parameters, the activities of sucrose phosphate synthase, neutral invertase and acid invertase in the leaves of the grafted seedlings were increased significantly. The uptake of nutrients was improved with the contents of K, P, Na increased and the content of Cu decreased. When the concentration of Cu2+ stress was 800 micromol L(-1), the contents of Cu in the leaves and roots of the grafted seedlings were decreased by 31.3% and 15.2%, respectively. Endogenous hormone balance of seedlings was improved by grafting. In the grafted seedlings, the content of IAA and peroxidase activity were higher, whereas the contents of ABA, maleicdialdehyde, the activities of superoxide dismutase and catalase were lower than that in the control. It was concluded that the copper stress on the physiological characters of melon seedlings was relieved by grafting which improved the resistance of the grafted seedlings. PMID:25876409

  15. Dynamic analysis of Lactobacillus delbrueckii subsp. bulgaricus CFL1 physiological characteristics during fermentation.

    PubMed

    Rault, Aline; Bouix, Marielle; Béal, Catherine

    2008-12-01

    This study aimed at examining and comparing the relevance of various methods in order to discriminate different cellular states of Lactobacillus bulgaricus CFL1 and to improve knowledge on the dynamics of the cellular physiological state during growth and acidification. By using four fluorescent probes combined with multiparametric flow cytometry, membrane integrity, intracellular esterase activity, cellular vitality, membrane depolarization, and intracellular pH were quantified throughout fermentations. Results were compared and correlated with measurements of cultivability, acidification activity (Cinac system), and cellular ability to recover growth in fresh medium (Bioscreen system). The Cinac system and flow cytometry were relevant to distinguish different physiological states throughout growth. Lb. bulgaricus cells maintained their high viability, energetic state, membrane potential, and pH gradient in the late stationary phase, despite the gradual decrease of both cultivability and acidification activity. Viability and membrane integrity were maintained during acidification, at the expense of their cultivability and acidification activity. Finally, this study demonstrated that the physiological state during fermentation was strongly affected by intracellular pH and the pH gradient. The critical pHi of Lb. bulgaricus CFL1 was found to be equal to pH 5.8. Through linear relationships between dpH and cultivability and pHi and acidification activity, pHi and dpH well described the time course of metabolic activity, cultivability, and viability in a single analysis. PMID:18800182

  16. [Impacts of Algal blooms accumulation on physiological ecology of water hyacinth].

    PubMed

    Wu, Ting-ting; Liu, Guo-feng; Han, Shi-qun; Zhou, Qing; Tang, Wan-ying

    2015-01-01

    Blue-green algae bloom will consume plenty of dissolved oxygen in water, which affects the growth of aquatic plants. The effects of water hyacinth growth and physiological response changes under 25 degrees C, 5 different concentrations of cyanobacteria gathered were studied and which would provide a theoretical basis to mitigate adverse impacts and improve water purification effect. The results showed that water quality indexes including dissolved oxygen (DO), pH dropped in algae density below 60 g x L(-1), with the increase of algae density. And the level of oxidation-reduction potential dropped to about 100 mV. The removal rates of TN, TP and COD were 58%-78%, 43%-68% and 59%-73%, leaf soluble protein, soluble sugar, MDA contents increased, respectively; and the MDA content became higher with the increase of algae density. It indicated that the water hyacinth could adapt to the adversity condition as algae density less than 60 g x L(-1). While algae density above 60 g x L(-1), water quality indexes significantly decreased, respectively and the water was in hypoxia or anoxia conditions. Plant leaves soluble sugar contents had a change trend of low-high-low. It indicated that the removal rates of TN, TP decreased with the increase of algae density and water hyacinth had irreversible stress. Plant root length, total length, fresh weight in different treatments, increased compared with the beginning of the experiment, the increase of root length, total length and fresh weight were 0.29-2.44 times, 0.41-0.76 times and 0.9-1.43 times. The increase of root length, total length decreased with the increase of algae density. According to the results, the cyanobacteria should avoid of excessive accumulation as using the floating plant to purify the water. PMID:25898654

  17. Physiological effects of sublethal levels of acid water on three species of fishes

    SciTech Connect

    Pegg, W.J.

    1984-01-01

    Static toxicity tests revealed the need to assess the effect of acid mine water using some procedure that would gradually increase the concentration of acidity over a period of time. A relatively long-term (2-5 days) experiment involving the devlopment of a sublethal acid treatment gradient was chosen as potentially being the most representative of natural environments which are periodically subjected to changing inputs from coal mine drainage. Since respiratory change is an indication of physiological stress, the measurement of oxygen consumption rate was chosen as the major variable representing the effect of acid waters on fishes. Bluegill sunfish Lepomes macrochirus Rafinesque, pumpkinseed sunfish, Lepomis gibbosus (Linnaeus), and brown bullhead, Ictalurus nebulosus (LeSueur) were collected from the Monongahela River and backwater areas in the region of Morgantown, West Virginia. The sublethal acid water treatments decreased the oxygen consumption rates for brown bullhead and bluegill sunfish, while increasing the oxygen consumption rate for pumpkinseed sunfish. Further, the rhythms of the oxygen consumption rates were generally modified in both frequency and amplitude as a result of exposure to acid water. Acid water treatments also caused negative phase shifts in oxygen consumption rate for brown bullhead sand bluegill sunfish, while positive phase shifts occurred for pumpkinseed sunfish.

  18. Pros and Cons of Using Water Immersion to Simulate Physiological Responses to Microgravity

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Tomko, David L. (Technical Monitor)

    1995-01-01

    Head-out water immersion (HOI) has been employed as a remedial treatment for various ills and ailments for many millennia, and total body immersion even longer as protective encapsulation for the mammalian fetus. Two discrete differences between stimuli induced by true microgravity (10(exp -4) g) and HOI are readily apparent. External water pressure on the skin and accompanying negative pressure breathing cause blood to shift headward. Secondly, the gravitational force is ever present during immersion and microgravity, but its effect is essentially neutralized during Earth orbital flight. Thus, the physiological responses to immersion should not be expected to match those during microgravity. Immersion has been used mainly to study and understand kidney function and associated cardiovascular responses for control of body fluid volume and osmotic content, with some application to and simulation of microgravity responses. There is a plethora of data from human HOI studies, but relatively few controlled data from microgravity studies. In general, it appears that physiological responses occur more quickly with water immersion than in microgravity, but this may be due to less rigorous control (voluntary and involuntary) of the preflight state of crew members. The central venous pressure-vasopressin (Gauer-Henry) reflex control for fluid balance may not be of prime importance in microgravity. Gross functions such as reduced body weight and water, level of hypovolemia, decreased isokinetic strength, and lower nitrogen balance found during immersion are qualitatively similar in microgravity, but the mechanisms controlling these and other functions are, for the most part, unclear. Only acquisition of data from well-controlled microgravity experiments will resolve this discrepancy.

  19. Characteristics of ocean waters reaching Greenland's glaciers Fiammetta STRANEO,1

    E-print Network

    Johnson, Helen

    Characteristics of ocean waters reaching Greenland's glaciers Fiammetta STRANEO,1 David A of Geography, University of British Columbia, Vancouver, Canada ABSTRACT. Interaction of Greenland's marine the glaciers range from 4.588C in the southeast, to 0.168C in northwest Greenland, consistent with the distance

  20. A climatological data base of arctic water vapor characteristics

    Microsoft Academic Search

    M. C. Serreze; M. C. Rehder; R. G. Barry; J. D. Kahl

    1994-01-01

    Using a blend of rawinsonde ascents from fixed stations, ships, and Russian drifting ice stations, a gridded climatological monthly?mean data base of Arctic water vapor characteristics is assembled that is suitable for use as input and validation data for simulations of Arctic climate from general circulation models. Preparation of the data base is described and examples of selected data fields

  1. Response Characteristics of Boiling Water Reactor Generating Units

    Microsoft Academic Search

    Douglas Carroll; Markus Eggenberger; Donald Ewart

    1973-01-01

    The IEEE Working Group on Power Plant Response to Load Changes has encouraged papers on various aspects of plant response. This paper is intended to contribute to the understanding of the response characteristics of a major class of power generation equipment, namely Boiling Water Reactor (BWR) plants as furnished by General Electric Company.

  2. Effects of water sulfate concentration on performance, water intake, and carcass characteristics of feedlot steers1

    Microsoft Academic Search

    G. H. Loneragan; J. J. Wagner; D. H. Gould; F. B. Garry; M. A. Thoren

    Two hundred forty single-source, cross- bred steers (304 kg) were used to evaluate the effects of various water sulfate concentrations on performance, water intake, and carcass characteristics of feedlot steers. Cattle were stratified by weight and assigned within weight blocks to five water treatments. Averaged over time, actual water sulfate concentrations (± SEM) were 136.1 (± 6.3), 291.2 (± 15.3),

  3. Water sensor ppk28 modulates Drosophila lifespan and physiology through AKH signaling.

    PubMed

    Waterson, Michael J; Chung, Brian Y; Harvanek, Zachary M; Ostojic, Ivan; Alcedo, Joy; Pletcher, Scott D

    2014-06-01

    Sensory perception modulates lifespan across taxa, presumably due to alterations in physiological homeostasis after central nervous system integration. The coordinating circuitry of this control, however, remains unknown. Here, we used the Drosophila melanogaster gustatory system to dissect one component of sensory regulation of aging. We found that loss of the critical water sensor, pickpocket 28 (ppk28), altered metabolic homeostasis to promote internal lipid and water stores and extended healthy lifespan. Additionally, loss of ppk28 increased neuronal glucagon-like adipokinetic hormone (AKH) signaling, and the AKH receptor was necessary for ppk28 mutant effects. Furthermore, activation of AKH-producing cells alone was sufficient to enhance longevity, suggesting that a perceived lack of water availability triggers a metabolic shift that promotes the production of metabolic water and increases lifespan via AKH signaling. This work provides an example of how discrete gustatory signals recruit nutrient-dependent endocrine systems to coordinate metabolic homeostasis, thereby influencing long-term health and aging. PMID:24821805

  4. Water sensor ppk28 modulates Drosophila lifespan and physiology through AKH signaling

    PubMed Central

    Waterson, Michael J.; Chung, Brian Y.; Harvanek, Zachary M.; Ostojic, Ivan; Alcedo, Joy; Pletcher, Scott D.

    2014-01-01

    Sensory perception modulates lifespan across taxa, presumably due to alterations in physiological homeostasis after central nervous system integration. The coordinating circuitry of this control, however, remains unknown. Here, we used the Drosophila melanogaster gustatory system to dissect one component of sensory regulation of aging. We found that loss of the critical water sensor, pickpocket 28 (ppk28), altered metabolic homeostasis to promote internal lipid and water stores and extended healthy lifespan. Additionally, loss of ppk28 increased neuronal glucagon-like adipokinetic hormone (AKH) signaling, and the AKH receptor was necessary for ppk28 mutant effects. Furthermore, activation of AKH-producing cells alone was sufficient to enhance longevity, suggesting that a perceived lack of water availability triggers a metabolic shift that promotes the production of metabolic water and increases lifespan via AKH signaling. This work provides an example of how discrete gustatory signals recruit nutrient-dependent endocrine systems to coordinate metabolic homeostasis, thereby influencing long-term health and aging. PMID:24821805

  5. RELATIONSHIPS BETWEEN HEART RATE AND PHYSIOLOGICAL PARAMETERS OF PERFORMANCE IN TOP-LEVEL WATER POLO PLAYERS

    PubMed Central

    Ben Zoubir, S.; Hambli, M.; Chaouachi, A.; Hue, O.; Chamari, K.

    2014-01-01

    The aim of this study was to measure the heart rate (HR) response of eight elite water polo players during the four 7-min quarters of the game and to check for relationships with the physiological parameters of performance (V.O2max, Th1vent, Th2vent). Each athlete performed a V.O2max treadmill test and played a water polo game wearing a heart rate monitor. The game fatigue index was calculated as the ratio of the fourth-quarter HR to the first-quarter HR: HR4/HR1. The results showed a slight decrease in fourth-quarter HR compared with the first quarter, with the mean four-quarter HR equal to 79.9±4.2% of HRmax. Stepwise multiple regression analysis showed V.O2max to be the main explanatory factor of game intensity, i.e. game HR expressed in %HRreserve (R=0.88, P<0.01). We observed that higher aerobic capacity resulted in higher game intensity. We also observed a decrease in the playing intensity in the fourth quarter compared with the first, likely due to very high game involvement. We concluded that high aerobic capacity seems necessary to ensure high game intensity in water polo. This suggests that coaches should encourage their athletes to reach a minimum level of V.O2max and that HR monitoring could be of great interest in the control of water polo training sessions. PMID:24917687

  6. Novel mineral-oxidizing bacteria from Montserrat (W.I.): physiological and phylogenetic characteristics

    SciTech Connect

    A. Yahya; F. F. Roberto; D. B. Johnson

    1999-06-01

    Four mesophilic acidophilic bacteria isolated from the Caribbean island of Montserrat have been studied to establish their taxonomic relationship to other metal-metabolizing bacteria and to analyze their potential role in mineral processing. Two of the isolates have some physiological and morphological traits in common with Thiobacillus ferrooxidans (Gram negative, iron-oxidizing mesophilic rods) but differed from T. ferrooxidans in displaying chemolitho-heterotrophic growth in ferrous iron/yeast extract medium and greater sensitivity to some metals. Isolates RIV-14 and L-15 were, in contrast, Gram positive, spore-forming rods that displayed considerable metabolic flexibility, and resembled moderately thermophilic Sulfobacillus spp. All the Montserrat isolates were able to oxidize pyrite in pure culture.

  7. [Effects of Ni2+ on physiological characteristics and submicroscopic structure of Salvinia natans leaves].

    PubMed

    Ji, Wang-dong; Shi, Guo-xin; Xu, Qin-song; Xu, Ye; Yang, Hai-yan; Du, Kai-he

    2008-08-01

    Influence of 0, 5, 10, 15, 20 mg/L Ni2+ on growth, mineral nutrition, chlorophyll, carotenoid, soluble protein, soluble sugar, superoxide (O2*-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents as well as the activities of superoxide dismutase (SOD), guaiacolperoxidase (POD), and catalase (CAT) were studied in the leaves of Salvinia natans plants on 10 days after treatment. With the increase of the Ni2+ concentrations, exposure of the plants revealed that, (1) the addition of Ni2+ affected the absorption of mineral nutrients, it mainly increased the absorption of Ca2+, Na+, Zn2+, Fe3+ and Mg2+, while reduced that of Mn2+, Mo2+, P and K+. (2) The content of chlorophyll, carotenoid, soluble protein and soluble sugar content as well as activities of SOD and CAT decreased gradually. That of O2*-, H2O2 and MDA content as well as POD activity increased, 383%, 168%, 207%, 131% of these controls, respectively. (3) In the leaves of Ni2+ -treated fronds, the polypeptide with apparent molecular weights 94000, was became visible in SDS-PAGE, and the nature of it remains to be determined. The amount and intensity of polypeptide band increased gradually with augment of Ni2+ was also observed, the polypeptide with apparent molecular weight 35,000 increased significantly in fronds. (4) Transmission electron microscope observation indicated that Ni2+ also imposed injury action on submicroscopic structure of leaf cells, disaggregation of nucleolus, agglutination and disappearance of chromatin of nucleus, disruption of nuclear membrane, swelling of thylakoids and breakage of chloroplast envelope, decreasing of cristae quantity and vacuolization of mitochondria. The conclusion could be reached that the plant death was resulted from destruction under structure foundation of physiological function, unbalance of ion equilibrium and disorder of physiological metabolism. PMID:18839591

  8. Morphological and Physiological Characteristics of Laminar Cells in the Central Nucleus of the Inferior Colliculus

    PubMed Central

    Wallace, Mark N.; Shackleton, Trevor M.; Palmer, Alan R.

    2012-01-01

    The central nucleus of the inferior colliculus (IC) is organized into a series of fibro-dendritic laminae, orthogonal to the tonotopic progression. Many neurons have their dendrites confined to one lamina while others have dendrites that cross over a number of laminae. Here, we have used juxtacellular labeling in urethane anesthetized guinea pigs to visualize the cells with biocytin and have analyzed their response properties, in order to try and link their structure and function. Out of a sample of 38 filled cells, 15 had dendrites confined within the fibro-dendritic laminae and in 13 we were also able to reconstruct their local axonal tree. Based on dendritic morphology they were subdivided into flat or less flat; small, medium, or large; elongated or disk-shaped cells. Two of the elongated cells had many dendritic spines while the other cells had few or none. Twelve of the cells had their local axonal tree restricted to the same lamina as their dendrites while one cell had its dendrites in a separate lamina from the axon. The axonal plexus was more extensive (width 0.7–1.4?mm) within the lamina than the dendrites (width generally 0.07–0.53?mm). The intrinsic axons were largely confined to a single lamina within the central nucleus, but at least half the cells also had output axons with two heading for the commissure and five heading into the brachium. We were able to identify similarities in the physiological response profiles of small groups of our filled cells but none appeared to represent a homogeneous morphological cell type. The only common feature of our sample was one of exclusion in that the onset response, a response commonly recorded from IC cells, was never seen in laminar cells, but was in cells with a stellate morphology. Thus cells with laminar dendrites have a wide variety of physiological responses and morphological subtypes, but over 90% have an extensive local axonal tree within their local lamina. PMID:22933991

  9. Physiological responses to hyper-saline waters in sailfin mollies (Poecilia latipinna).

    PubMed

    Gonzalez, R J; Cooper, J; Head, D

    2005-12-01

    We examined the ionoregulatory physiology and biochemistry of the teleost sailfin molly (Poecilia latipinna), an inhabitant of salt marshes along the gulf coast, during exposure to hyper-saline waters (salinity range 35-95 ppt). Mollies were able to tightly control plasma Na(+) and Cl(-) concentrations and tissue water levels up to 65 ppt, but at higher salinities plasma ion levels began to rise and muscle water content dropped. Still, even at the highest salinity (90 ppt) plasma Na(+) and Cl(-) levels were only 32% and 39%, respectively, above levels at 35 ppt. Drinking rates at 60 ppt climbed 35%, while gut Na(+)/K(+)-ATPase (NAK) activity rose 70% and branchial NAK activity jumped 200%. The relatively small rise in drinking rate, in the face of a more than doubling of the osmotic gradient, suggests that a reduction in branchial water permeability significantly limited water loss and associated salt load. At 80 ppt, a salinity where plasma ion levels just begin to rise, drinking rate rose more rapidly, but gut and gill NAK activity did not, suggesting that mollies employed other pathways (perhaps renal) of salt excretion. At higher salinities, plasma ion levels continued to rise and muscle water content fell slightly indicating the beginnings of internal osmotic disturbances. To evaluate the energetic costs of hyper-salinity on mollies we measured the rate of O(2) consumption and found it rose with salinity, in sharp contrast to virtually all species previously examined. Interestingly, despite higher metabolism, growth was unaffected by hyper-salinity. PMID:16257552

  10. Controlled alternate partial root-zone irrigation: its physiological consequences and impact on water use efficiency.

    PubMed

    Kang, Shaozhong; Zhang, Jianhua

    2004-11-01

    Controlled alternate partial root-zone irrigation (CAPRI), also called partial root-zone drying (PRD) in other literature, is a new irrigation technique and may improve the water use efficiency of crop production without significant yield reduction. It involves part of the root system being exposed to drying soil while the remaining part is irrigated normally. The wetted and dried sides of the root system are alternated with a frequency according to soil drying rate and crop water requirement. The irrigation system is developed on the basis of two theoretical backgrounds. (i) Fully irrigated plants usually have widely opened stomata. A small narrowing of the stomatal opening may reduce water loss substantially with little effect on photosynthesis. (ii) Part of the root system in drying soil can respond to the drying by sending a root-sourced signal to the shoots where stomata may be inhibited so that water loss is reduced. In the field, however, the prediction that reduced stomatal opening may reduce water consumption may not materialize because stomatal control only constitutes part of the total transpirational resistance. The boundary resistance from the leaf surface to the outside of the canopy may be so substantial that reduction in stomatal conductance is small and may be partially compensated by the increase in leaf temperature. It is likely that densely populated field crops, such as wheat and maize, may have a different stomatal control over transpiration from that of fruit trees which are more sparsely separated. It was discussed how long the stomata can keep 'partially' closed when a prolonged and repeated 'partial' soil drying is applied and what role the rewatering-stimulated new root growth may play in sensing the repeated soil drying. The physiological and morphological alternation of plants under partial root-zone irrigation may bring more benefits to crops than improved water use efficiency where carbon redistribution among organs is crucial to the determination of the quantity and quality of the products. PMID:15361526

  11. Seven years of enhanced water availability influences the physiological, structural, and functional attributes of a soil microbial community

    Microsoft Academic Search

    Mark A. Williams; Charles W. Rice

    2007-01-01

    Water availability is known to influence many aspects of microbial growth and physiology, but less is known about how complex soil microbial communities respond to changing water status. To understand how long-term enhancement of soil water availability (without flooding) influences microbial communities, we measured the seasonal dynamics of several community-level traits following >7 years of irrigation in a drought-prone tallgrass

  12. Variation of physiological and antioxidative responses in tea cultivars subjected to elevated water stress followed by rehydration recovery

    Microsoft Academic Search

    Hrishikesh Upadhyaya; Sanjib Kumar Panda; Biman Kumar Dutta

    2008-01-01

    Water stress is a major limitation for plant survival and growth. Several physiological and antioxidative mechanisms are involved\\u000a in the adaptation to water stress by plants. In this experiment, tea cultivars (TV-1, TV-20, TV-29 and TV-30) were subjected\\u000a to drought stress by withholding water for 20 days followed by rehydration. An experiment was thus performed to test and compare\\u000a the effect

  13. Physiological Effect Of Auxins On Growth Characteristics And Productive Potential Of Verbascum thapsus - A Medicinal Plant

    Microsoft Academic Search

    Snehlata Bhandari; Mamta Sajwan; N. S. Bisht

    Due to current revival of interest in herbal drugs and pharmaceuticals, demand for medicinal plants is increasing day by day leading to destructive harvesting which ultimately has resulted into reduction and even extinction of many rare medicinal plants. Plant growth regulators like auxins have proved to increase the productivity and growth characteristics of many plants. They have proved their importance

  14. Physiology of Fluid and Electrolyte Responses During Inactivity: Water Immersion and Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1984-01-01

    This manuscript emphasizes the physiology of fluid-electrolyte-hormonal responses during the prolonged inactivity of bed rest and water immersion. An understanding of the total mechanism of adaptation (deconditioning) should provide more insight into the conditioning process. Findings that need to be confirmed during bed rest and immersion are: (1) the volume and tissues of origin of fluid shifted to the thorax and head; (2) interstitial fluid pressure changes in muscle and subcutaneous tissue, particularly during immersion; and (3) the composition of the incoming presumably interstitial fluid that contributes to the early hypervolemia. Better resolution of the time course and source of the diuretic fluid is needed. Important data will be forthcoming when hypotheses are tested involving the probable action of the emerging diuretic and natriuretic hormones, between themselves and among vasopressin and aldosterone, on diuresis and blood pressure control.

  15. Assessing environmental and physiological controls over water relations in a Scots pine (Pinus sylvestris L.) stand through analyses of stable isotope composition of water and organic matter

    Microsoft Academic Search

    ELKE BRANDES; JOCHEN WENNINGER; PAUL KOENIGER; DIRK SCHINDLER; HEINZ RENNENBERG; CHRISTIAN LEIBUNDGUT; HELMUT MAYER; ARTHUR GESSLER

    2007-01-01

    This study investigated the influence of meteorological, pedospheric and physiological factors on the water rela- tions of Scots pine, as characterized by the origin of water taken up, by xylem transport as well as by carbon isotope discrimination (D 13 C) and oxygen isotope enrichment

  16. Multiple regression models: A methodology for evaluating trihalomethane concentrations in drinking water from raw water characteristics

    Microsoft Academic Search

    Spyros K. Golfinopoulos; George B. Arhonditsis

    2002-01-01

    The presence of trihalomethanes (THMs) in drinking water has attracted the attention of both researchers and professionals, because of the harmful effects of these substances on human health. A multiple regression model was developed to estimate THM concentrations in finished drinking water, using data from the Menidi Treatment Plant of Athens. A number of routinely measured characteristics––including chlorine dose, chlorophyll

  17. Structural characteristics of thermosensitive chitosan glutamate hydrogels in variety of physiological environments

    NASA Astrophysics Data System (ADS)

    Modrzejewska, Z.; Nawrotek, K.; Maniukiewicz, W.; Douglas, T.

    2014-09-01

    In this paper the properties of thermosensitive chitosan hydrogels prepared with the use of chitosan glutamate and ?-glycerophosphate are presented. The study is focused on the determination of changes in the hydrogel structure in different environments: during conditioning in water and buffer at pH 7 and pH 2 respectively. The structure of gels was observed under the Scanning Electron Microscopy (SEM) and was investigated by infrared (IR) spectroscopy. The crystallinity of gel structure was determined by X-ray diffraction analysis (XRD). On the basis of structural changes during the conditioning in water a mechanism of their formation was proposed.

  18. Behaviour, physiological states and thermal characteristics of aggregating male Hybomitra illota (Diptera: Tabanidae).

    PubMed

    Taylor, P D; Smith, S M

    1990-07-01

    Male Hybomitra illota (Osten Sacken) were found aggregating in clearings in wooded areas in Rondeau Provincial Park, Ontario, Canada. At these sites they perched on a variety of substrates, and made frequent flights in pursuit of insects flying overhead. We know that these pursuit flights were part of the mating behaviour because some pursuits of female H. illota resulted in copulation. We call the aggregation sites 'mating arenas' and the behaviour exhibited by males 'perch-and-pursue'. Aggregation occurred only on sunny days, when ambient temperatures exceeded 18 degrees C. Males perched in sunny areas, except during hot afternoons, when some males were found in dappled shade. Some marked males remained at or returned to sites for up to 13 days, but most males did not remain at the same area within a site, even during the same day. The contents of the oesophageal diverticula of males were depleted daily. Concentration of diverticular carbohydrates changed through the season. Thoracic temperatures of males were high (c. 37 degrees C) and were regulated, probably both behaviourally and physiologically. The sites and behaviour of male H.illota at aggregation arenas bear some resemblance to lek sites and lekking in vertebrates. Males are aggregated in an arena but, within the perching component of the behaviour, we saw no evidence of male territoriality, display, or female choice. However, competition, display, or mate choice could occur within the pursuit-flight component. PMID:2133001

  19. Interplay between product characteristics, oral physiology and texture perception of cellular brittle foods

    Microsoft Academic Search

    Vliet van T; C. Primo Martin

    2011-01-01

    Hard solid foods encompass a large variety of dry products as well as products with high water content. Most of these foods have a cellular structure, which is generally characterized by connected fairly rigid cell walls, enclosing a fluid material that may be liquid-like (fruit and vegetables) or a gas (mainly manufactured cellular foods). Typical for many hard solid products

  20. Toxic Effect of Certain Metals Mixture on Some Physiological and Morphological Characteristics of Freshwater Algae

    Microsoft Academic Search

    Salwa A. Shehata; Mohamed R. Lasheen; Gamila H. Ali; Imam A. Kobbia

    1999-01-01

    The toxic effect of multi metals mixture which exist simultaneously in aquatic ecosystem on natural phytoplankton assemblages (green algae, blue-green algae and diatoms) was studied. For this purpose a laboratory scale unit was designed to evaluate the effect of continuous flow metals mixture in forms if triple and penta metals in Nile water algae. Clear changes in algal biomass in

  1. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  2. The subject of water balance has been central to insect physiology for over a century. The high surface area:volume

    E-print Network

    Ahmad, Sajjad

    The subject of water balance has been central to insect physiology for over a century. The high, 1994). These studies have revealed some expected physiological differences, such as a reduction despite its lack of current utility. Without both physiological and phylogenetic information on closely

  3. Pulmonary arterial hypertension in Saudi Arabia: Patients' clinical and physiological characteristics and hemodynamic parameters. A single center experience

    PubMed Central

    Idrees, MM; Al-Najashi, K; Khan, A; Al-Dammas, S; Al-Awwad, H; Batubara, E; Al Otai, A; Abdulhameed, J; Fayed, A; Kashour, T

    2014-01-01

    AIMS: The main objective of this study is to describe patients' clinical characteristics and physiological and hemodynamic parameters at the time of diagnosis in a pulmonary hypertension center in Saudi Arabia. MATERIALS AND METHODS: This study reports the results from a single pulmonary hypertension specialized center in Riyadh, Saudi Arabia, namely Prince Sultan Medical Military City/Cardiac Center (PSMMC & CC). Both newly diagnosed (incidence) and referred (prevalence) cases of pulmonary arterial hypertension are included. All characteristics, including clinical, physiological, and hemodynamic parameters at the time of diagnosis are described. RESULTS: A total of 107 patients were identified as having pulmonary arterial hypertension as diagnosed by right heart catheterization. The mean age at diagnosis was 36 (± 9) years, and there was a female preponderance of 62.6%. The mean duration between symptom onset and diagnosis was 27.8 (± 9.0) months. At the time of enrollment, 56.1% of patients were in functional class III and 16.8% were in functional class IV. Fifty five patients (51.4%) were diagnosed as idiopathic pulmonary arterial hypertension, 29 patients (27.1%) as congenital heart disease associated with pulmonary arterial hypertension, 16 patients (15.0%) as connective tissue diseases associated with pulmonary arterial hypertension, 4 patients (3.7%) as heritable pulmonary arterial hypertension, and 3 patients (2.8%) as portopulmonary hypertension. CONCLUSION: This data highlights the current situation of pulmonary arterial hypertension in Saudi Arabia. Our patients are much younger than patients described in other international registries but still detected as late in the course of the disease. A majority of patients displays severe functional and hemodynamic compromise. PMID:25276239

  4. Effect of seedling age and water depth on morphological and physiological aspects of transplanted rice under high temperature

    PubMed Central

    Khakwani, Abdul Aziz; Shiraishi, Masaaki; Zubair, Muhammad; Baloch, Mohammad Safdar; Naveed, Khalid; Awan, Inayatullah

    2005-01-01

    To study the effect of high temperature, rice seedlings 20, 30, 40 and 50 d were kept at 5, 10, 15 and 20 cm water depth in a water pool. Meteorological findings indicated that water temperature varied up to 10 cm but became stable below this depth. Deep water inflicted higher tiller mortality, minimal increase in dry weight of aerial parts and leaf area, decrease in root length, and decrease in root dry weight especially at 20 cm water depth and produced an unbalanced T/R ratio (top versus root dry weight). However, deep water tended to increase plant length. These parameters, however, excel in shallow water. Older seedlings, with the exception of root dry weight, could not perform well compared to young seedlings in all physiological and morphological aspects. The study revealed that seedlings, particularly young ones, stand well in shallow water and can cope with high temperature. PMID:15822153

  5. FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY MANAGEMENT: PROCEEDINGS OF AN INTERNATIONAL SYMPOSIUM, SACRAMENTO, CALIFORNIA, USA, SEPTEMBER 18-20, 1993

    EPA Science Inventory

    Scientists from five countries presented papers at the Second International Symposium on Fish Physiology, Toxicology, and Water Quality Management, which was held in Sacramento, California, on September 18-20, 1990. his proceedings includes 21 papers presented in sessions on the ...

  6. Physiological strategies of co-occurring oaks in a water- and nutrient-limited ecosystem.

    PubMed

    Renninger, Heidi J; Carlo, Nicholas; Clark, Kenneth L; Schäfer, Karina V R

    2014-02-01

    Oak species are well suited to water-limited conditions by either avoiding water stress through deep rooting or tolerating water stress through tight stomatal control. In co-occurring species where resources are limited, species may either partition resources in space and/or time or exhibit differing efficiencies in the use of limited resources. Therefore, this study seeks to determine whether two co-occurring oak species (Quercus prinus L. and Quercus velutina Lam.) differ in physiological parameters including photosynthesis, stomatal conductance, water-use (WUE) and nitrogen-use efficiency (NUE), as well as to characterize transpiration and average canopy stomatal responses to climatic variables in a sandy, well-drained and nutrient-limited ecosystem. The study was conducted in the New Jersey Pinelands and we measured sap flux over a 3-year period, as well as leaf gas exchange, leaf nitrogen and carbon isotope concentrations. Both oak species showed relatively steep increases in leaf-specific transpiration at low vapor pressure deficit (VPD) values before maximum transpiration rates were achieved, which were sustained over a broad range in VPD. This suggests tight stomatal control over transpiration in both species, although Q. velutina showed significantly higher leaf-level and canopy-level stomatal conductance than Q. prinus. Average daytime stomatal conductance was positively correlated with soil moisture and both oak species maintained at least 75% of their maximum canopy stomatal conductance at soil moistures in the upper soil layer (0-0.3 m) as low as 0.03 m(3) m(3)(-3). Quercus velutina had significantly higher photosynthetic rates, maximum Rubisco-limited and electron-transport-limited carboxylation rates, dark respiration rates and nitrogen concentration per unit leaf area than Q. prinus. However, both species exhibited similar WUEs and NUEs. Therefore, Q. prinus has a more conservative resource-use strategy, while Q. velutina may need to exploit niches that are locally higher in nutrients and water. Likewise, both species appear to tap deep, stable water sources, highlighting the importance of rooting depth in modeling transpiration and stomatal conductance in many oak ecosystems. PMID:24488856

  7. Physiologic, metabolic, and muscle fiber type characteristics of musculus uvulae in sleep apnea hypopnea syndrome and in snorers.

    PubMed Central

    Sériès, F; Côté, C; Simoneau, J A; Gélinas, Y; St Pierre, S; Leclerc, J; Ferland, R; Marc, I

    1995-01-01

    Upper airway dilator muscles play an important role in the pathophysiology of sleep apnea hypopnea syndrome (SAHS). The mechanical and structural characteristics of these muscles remain unknown. The aim of this study was to compare the physiologic, metabolic, and fiber type characteristics of one upper airway dilator muscle (musculus uvulae, MU) in 11 SAHS and in seven nonapneic snorers. The different analyses were done on MU obtained during uvulo-palato-pharyngoplasty. Snorers and SAHS differed only in their apnea + hypopnea indices (11.5 +/- 5.9 and 34.2 +/- 14.6/h, respectively, mean +/- SD). Absolute twitch and tetanic tension production of MU was significantly greater in SAHS than in snorers while the fatigability index was similar in the two groups. Protein content and anaerobic enzyme activities of MU were significantly greater in SAHS than in snorers; no difference was observed for aerobic enzyme activities. The total muscle fiber cross-sectional area of MU was significantly higher in SAHS (2.2 +/- 0.9 mm2) than in snorers (1.1 +/- 0.7 mm2). The surface occupied by type IIA muscle fibers of MU was larger in SAHS (2.00 +/- 0.96) than in snorers (0.84 +/- 0.63 mm2). We conclude that the capacity for tension production and the anaerobic metabolic activity of MU are greater in SAHS than in snorers. PMID:7814616

  8. Physiological effects of aluminum on rainbow trout in acidic soft water, with emphasis on the gill micro-environment

    Microsoft Academic Search

    Richard Colin Playle

    1989-01-01

    This thesis examined the physiological and toxicological effects of Al (-100 ?g.L?¹) in acidic soft water (pH 4.0-6.5) on the rainbow trout (Salmo gairdneri = Oncorhynchus mykiss), and the mechanisms of Al deposition on the gills. Cannulated trout exposed for 66 h to Al in synthetic soft water (Ca²? = 45 or 410 ?equiv.L?¹) showed highest mortality at pH 5.2,

  9. Physiological effects of aluminum on rainbow trout in acidic soft water, with emphasis on the gill micro-environment

    Microsoft Academic Search

    Richard Colin Playle

    1990-01-01

    This thesis examined the physiological and toxicological effects of AL ($\\\\sim$100 $\\\\mu$g.L$\\\\sp{-1}$) in acidic soft water (pH 4.0-6.5) on the rainbow trout (Salmo gairdneri = Oncorhynchus mykiss), and the mechanisms of Al deposition on the gills. Cannulated trout exposed for 66 h to Al in synthetic soft water (Ca$\\\\sp{2+}$ = 45 or 410 $\\\\mu$equiv.L$\\\\sp{-1}$) showed highest mortality at pH 5.2,

  10. Molecular, Physiological and Biochemical Responses of Theobroma cacao L. Genotypes to Soil Water Deficit

    PubMed Central

    dos Santos, Ivanildes C.; de Almeida, Alex-Alan Furtado; Anhert, Dário; da Conceição, Alessandro S.; Pirovani, Carlos P.; Pires, José L.; Valle, Raúl René; Baligar, Virupax C.

    2014-01-01

    Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (?WL) ranging from ?0.1 to ?0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ?WL reached values of between ?2.0 to ?2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought. PMID:25541723

  11. Characteristics of a root hair-less line of Arabidopsis thaliana under physiological stresses

    PubMed Central

    Maeshima, Masayoshi

    2014-01-01

    The plasma membrane-associated Ca2+-binding protein-2 of Arabidopsis thaliana is involved in the growth of root hair tips. Several transgenic lines that overexpress the 23 residue N-terminal domain of this protein under the control of the root hair-specific EXPANSIN A7 promoter lack root hairs completely. The role of root hairs under normal and stress conditions was examined in one of these root hair-less lines (NR23). Compared with the wild type, NR23 showed a 47% reduction in water absorption, decreased drought tolerance, and a lower ability to adapt to heat. Growth of NR23 was suppressed in media deficient in phosphorus, iron, calcium, zinc, copper, or potassium. Also, the content of an individual mineral in NR23 grown in normal medium, or in medium lacking a specific mineral, was relatively low. In wild-type plants, the primary and lateral roots produce numerous root hairs that become elongated under phosphate-deficient conditions; NR23 did not produce root hairs. Although several isoforms of the plasma membrane phosphate transporters including PHT1;1–PHT1;6 were markedly induced after growth in phosphate-deficient medium, the levels induced in NR23 were less than half those observed in the wild type. In phosphate-deficient medium, the amounts of acid phosphatase, malate, and citrate secreted from NR23 roots were 38, 9, and 16% of the levels secreted from wild-type roots. The present results suggest that root hairs play significant roles in the absorption of water and several minerals, secretion of acid phosphatase(s) and organic acids, and in penetration of the primary roots into gels. PMID:24501179

  12. Water mass characteristics and solar illumination influence leatherback turtle dive patterns at high latitudes

    E-print Network

    Taggart, Christopher

    Water mass characteristics and solar illumination influence leatherback turtle dive patterns. T. Taggart, and M. C. James. 2014. Water mass characteristics and solar illumination influence frequency is a function of seasonal change in daylight. Our findings illustrate that solar illumination

  13. Clinical characteristics of idiopathic pulmonary fibrosis patients with gender, age, and physiology staging at Okinawa Chubu Hospital

    PubMed Central

    Shimaoka, Yousuke; Fukuyama, Hajime; Nagano, Hiroaki; Nei, Yuichiro; Yamashiro, Shin; Tamaki, Hitoshi

    2015-01-01

    Background Gender, age, and physiology (GAP) staging was recently advocated for idiopathic pulmonary fibrosis (IPF). However, clinical findings of GAP staging for IPF are limited. We aimed to investigate the clinical characteristics of IPF patients according to GAP staging in our hospital. Methods We retrospectively reviewed patient medical records and chest high-resolution computed tomography (HRCT) images from June 1, 2002, to December 31, 2012. Results We identified 54 IPF patients with [36 men; mean age: 71 years (range, 53-85 years)]. Mean fibrosis and ground glass opacity (GGO) scores were 1.9 (0-4) and 1.6 (1-3.3), respectively. Mean percent predicted forced vital capacity (% FVC), percent predicted diffusing capacity of the lung for carbon monoxide (% DLco) were 70.6 (6.4-114.3), 49.2 (15-105.9), respectively. Cox proportional hazards model showed that gender, percent predicted diffusing capacity of the lung for carbon monoxide (% DLco), and composite physiologic index (CPI) were strong predictors of mortality. Stage III patients had more pulmonary hypertension (50% vs. 23%, 0%) and progressive modified Medical Research Council (mMRC) changes at 1 year (1.3 vs. 0.6, 1.1; P=0.07) compared with other stages. Conclusions In our cohort, GAP staging was useful for evaluating IPF severity. Stage III patients might had more pulmonary hypertension and progressive dyspnea. Multicenter analyses are warranted to confirm these findings. Keywords Idiopathic pulmonary fibrosis (IPF); modified Medical Research Council (mMRC); mortality; pulmonary hypertension; staging

  14. Measurement of "turbidity" and related characteristics of natural waters

    USGS Publications Warehouse

    Pickering, R.J.

    1976-01-01

    The U.S. Geological Survey, Water Resources Division has adopted the following principles to be used in selecting methods for the measurement of light transmitting characteristics of natural waters: (1) standard instruments and methods are to be adopted to measure and report in optical units, avoiding ' turbidity ' as a quantitative measure; (2) reporting of ' turbidity ' in JTU 's, Hellige units, severity, or NTU 's will be phased out; (3) the basis for estimations of sediment concentrations based on light measurements must be documented adequately; and (4) use of transparency measurement by Secchi disk is not changed, although light transmittance may prove to be more precise means of obtaining the same information. A schedule has been established to implement new methods beginning October 1, 1976, and with the transition to be completed at all stations by October 1, 1977. Provisions are provided to meet requirements of cooperators who have legal requirements for ' turbidity ' data. (Woodard-USGS)

  15. Physiological regulation of evaporative water loss in endotherms: is the little red kaluta (Dasykaluta rosamondae) an exception or the rule?

    PubMed Central

    Withers, Philip C.; Cooper, Christine E.

    2014-01-01

    It is a central paradigm of comparative physiology that the effect of humidity on evaporative water loss (EWL) is determined for most mammals and birds, in and below thermoneutrality, essentially by physics and is not under physiological regulation. Fick's law predicts that EWL should be inversely proportional to ambient relative humidity (RH) and linearly proportional to the water vapour pressure deficit (?wvp) between animal and air. However, we show here for a small dasyurid marsupial, the little kaluta (Dasykaluta rosamondae), that EWL is essentially independent of RH (and ?wvp) at low RH (as are metabolic rate and thermal conductance). These results suggest regulation of a constant EWL independent of RH, a hitherto unappreciated capacity of endothermic vertebrates. Independence of EWL from RH conserves water and heat at low RH, and avoids physiological adjustments to changes in evaporative heat loss such as thermoregulation. Re-evaluation of previously published data for mammals and birds suggests that a lesser dependence of EWL on RH is observed more commonly than previously thought, suggesting that physiological independence of EWL of RH is not just an unusual capacity of a few species, such as the little kaluta, but a more general capability of many mammals and birds. PMID:24741015

  16. Fluctuating water temperatures affect development, physiological responses and cause sex reversal in fathead minnows.

    PubMed

    Coulter, David P; Höök, Tomas O; Mahapatra, Cecon T; Guffey, Samuel C; Sepúlveda, Maria S

    2015-02-01

    Natural and human activities can result in both high temporal and spatial variability in water temperature. Rapid temperature changes have the potential to dramatically affect physiological processes in aquatic organisms and, due to their limited mobility, fish early life stages are particularly vulnerable to ambient temperature fluctuations. In this study, we examined how the magnitude and frequency of temperature fluctuations affect survival, growth, development, expression of thermoresponsive genes, and gonadal differentiation in fathead minnows, Pimephales promelas. We exposed individuals (0 to 4 days post fertilization) of known genotypic sex to fluctuations of ?4 °C over 12-h, ?8 °C over 12- and 24-h, and three stable temperatures (21, 25, and 29 °C) for up to 45 d. Expression of hsp70 in fish exposed to the highest-magnitude, highest-frequency fluctuating treatment cycled in concert with temperature and was upregulated initially during exposure, and may have contributed to temperature fluctuations having little effect on time to and size at hatching (whole-organism responses). This treatment also caused fish to undergo nondirectional sex reversal. These results indicate that hsp70 may be involved in mediating thermal stress from subdaily temperature fluctuations and that sex determination in fathead minnows can be influenced by cycling temperatures. PMID:25587805

  17. Spectral characteristics analysis of red tide water in mesocosm experiment

    NASA Astrophysics Data System (ADS)

    Cui, Tingwei; Zhang, Jie; Zhang, Hongliang; Ma, Yi; Gao, Xuemin

    2003-05-01

    Mesocosm ecosystem experiment with seawater enclosed of the red tide was carried out from July to September 2001. We got four species of biology whose quantities of bion are dominant in the red tide. During the whole process from the beginning to their dying out for every specie, in situ spectral measurements were carried out. After data processing, characteristic spectra of red tide of different dominant species are got. Via comparison and analysis of characteristics of different spectra, we find that in the band region between 685 and 735 nanometers, spectral characteristics of red tide is apparently different from that of normal water. Compared to spectra of normal water, spectra of red tide have a strong reflectance peak in the above band region. As to spectra of red tide dominated by different species, the situations of reflectance peaks are also different: the second peak of Mesodinium rubrum spectrum lies between 726~732 nm, which is more than 21nm away from the other dominant species spectra"s Leptocylindrus danicus"s second spectral peak covers 686~694nm; that of Skeletonema costatum lies between 691~693 nm. Chattonella marina"s second spectral peak lies about 703~705 nm. Thus we can try to determine whether red tide has occurred according to its spectral data. In order to monitor the event of red tide and identify the dominant species by the application of the technology of hyperspectral remote sensing, acquiring spectral data of different dominant species of red tide as much as possible becomes a basic work to be achieved for spectral matching, information extraction and so on based on hyperspectral data.

  18. Age- and size-related changes in physiological characteristics and chemical composition of Acer pseudoplatanus and Fraxinus excelsior trees.

    PubMed

    Abdul-Hamid, Hazandy; Mencuccini, Maurizio

    2009-01-01

    Forest growth is an important factor both economically and ecologically, and it follows a predictable trend with age. Generally, growth accelerates as canopies develop in young forests and declines substantially soon after maximum leaf area is attained. The causes of this decline are multiple and may be linked to age- or size-related processes, or both. Our objective was to determine the relative effects of tree age and tree size on the physiological attributes of two broadleaf species. As age and size are normally coupled during growth, an approach based on grafting techniques to separate the effects of size from those of age was adopted. Genetically identical grafted seedlings were produced from scions taken from trees of four age classes, ranging from 4 to 162 years. We found that leaf-level net photosynthetic rate per unit of leaf mass and some other leaf structural and biochemical characteristics had decreased substantially with increasing size of the donor trees in the field, whereas other gas exchange parameters expressed on a leaf area basis did not. In contrast, these parameters remained almost constant in grafted seedlings, i.e., scions taken from donor trees with different meristematic ages show no age-related trend after they were grafted onto young rootstocks. In general, the results suggested that size-related limitations triggered the declines in photosynthate production and tree growth, whereas less evidence was found to support a role of meristematic age. PMID:19203930

  19. Identification of high gamma-aminobutyric acid producing marine yeast strains by physiological and biochemical characteristics and gene sequence analyses.

    PubMed

    Guo, Xiao-feng; Aoki, Hitoshi; Hagiwara, Toshihiko; Masuda, Kazuaki; Watabe, Shugo

    2009-07-01

    Four marine yeasts isolated from the Pacific Ocean off Japan (Siki No. 4, Siki No. 15, Hach No. 6, and Inub No. 11), which showed high gamma-aminobutyric acid (GABA) producing abilities, were identified and classified by physiological and biochemical characteristics and gene sequence analyses. Analysis of biochemical data suggested that while Siki No. 15 was identical to Candida, the remaining three isolates belonged to the genus Pichia. However, these data were insufficient to resolve their identity at the species level. Subsequently, analysis of the 5.8S rRNA genes and the two internal transcribed spacer regions (ITS) sequences revealed that Siki No. 15 belongs to Pichia guilliermondii, while the remaining three isolates corresponded to Pichia anomala. Since Siki No. 4 showed slightly different biochemical properties than the other two isolates, which were otherwise identical, we sought to investigate the sequences of the intergenic spacer region 1 (IGS1). We observed few nucleotide changes, suggesting that the Hach No. 6 and Inub No. 11 isolates belong to different but new strains for which we propose the names P. anomola MR-1 and MR-2 respectively. PMID:19584549

  20. Within-catchment variation in regulation of water use by eucalypts, and the roles of stomatal anatomy and physiology

    NASA Astrophysics Data System (ADS)

    Gharun, Mana; Turnbull, Tarryn; Adams, Mark

    2014-05-01

    Understanding how environmental cues impact water use of forested catchments is crucial for accurate calculation of water balance and effective catchment management in terrestrial ecosystems. We characterised structural and physiological properties of leaves and canopies of Eucalyptus delegatensis, E. pauciflora and E. radiata, the most common species in high-country catchments in temperate Australia. These properties were related to whole-tree water transport to assess differences in water use strategies among the three species. Stomatal conductance, instantaneous transpiration efficiency, stomatal occlusion (through cuticular ledges) and leaf area index differed significantly among species. Whole-tree water use of all species was strongly coupled to changes in vapour pressure deficit (VPD) and photosynthetically active radiation (Q), yet stomatal closure reduced water transport at VPD > 1 kPa in all species, even when soil water was not limiting. The observed differences in leaf traits and related water use strategies reflect species-specific adaptations to dominant environmental conditions within the landscape matrix of catchments. The generalist E. radiata seems to follow an opportunistic, while the two more spatially restricted species have adopted a pessimistic water use strategy. Catchment-scale models of carbon and water fluxes will need to reflect such variation in structure and function, if they are to fully capture species effects on water balance and yield.

  1. Sensitivity of Terrestrial Water and Energy Budgets to CO2-Physiological Forcing: An Investigation Using an Offline Land Model

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, Ranjith; Bala, Govindsamy; Jayaraman, Mathangi; Cao, Long; Nemani, Ramakrishna; Ravindranath, N. H.

    2011-01-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) influence climate by suppressing canopy transpiration in addition to its well-known greenhouse gas effect. The decrease in plant transpiration is due to changes in plant physiology (reduced opening of plant stomata). Here, we quantify such changes in water flux for various levels of CO2 concentrations using the National Center for Atmospheric Research s (NCAR) Community Land Model. We find that photosynthesis saturates after 800 ppmv (parts per million, by volume) in this model. However, unlike photosynthesis, canopy transpiration continues to decline at about 5.1% per 100 ppmv increase in CO2 levels. We also find that the associated reduction in latent heat flux is primarily compensated by increased sensible heat flux. The continued decline in canopy transpiration and subsequent increase in sensible heat flux at elevated CO2 levels implies that incremental warming associated with the physiological effect of CO2 will not abate at higher CO2 concentrations, indicating important consequences for the global water and carbon cycles from anthropogenic CO2 emissions. Keywords: CO2-physiological effect, CO2-fertilization, canopy transpiration, water cycle, runoff, climate change 1.

  2. Water clarity, maternal behavior, and physiology combine to eliminate UV radiation risk to

    E-print Network

    Palen, Wendy J.

    of montane amphibians with contrasting physiological sensitivities, long-toed salamander (Ambystoma macrodactylum) and Cascades frog (Rana cascadae), at field sites spanning a gradient of UV-B attenuation

  3. Characteristic NMR spectra of proton transfer in protonated water clusters

    NASA Astrophysics Data System (ADS)

    Lao-ngam, Charoensak; Phonyiem, Mayuree; Chaiwongwattana, Sermsiri; Kawazoe, Yoshiyuki; Sagarik, Kritsana

    2013-07-01

    Characteristic NMR spectra of proton transfer in protonated water clusters were studied using the H+(H2O)n complexes, n = 2 - 5, as model systems, and ab initio calculations at the RIMP2/TZVP level and BOMD simulations as model calculations. Based on the concept of presolvation, two-dimensional potential energy surface of proton in the smallest, most active intermediate complex (the Zundel complex) was constructed as a function of the H-bond distance (RO-O) and the asymmetric stretching coordinate (?dDA). The low-interaction energy path and the path with ?dDA = 0 Å were analyzed and discussed in comparison with the model systems. The two proton transfer paths associate with the characteristic IR frequencies namely, the structural diffusion and oscillatory shuttling frequencies, respectively. RIMP2/TZVP calculations showed that the proton moving on the oscillatory shuttling path is characterized by the 1H NMR shielding constant (?H+corr) varying in a narrow range, whereas on the structural diffusion path, ?H+corr changes exponentially with RO-H. The energetic, dynamic and spectroscopic results obtained from BOMD simulations in the temperature range between 350 and 450 K validated the presolvation model and revealed that the activation energies for the proton exchange in the smallest, most active intermediate complex, computed from the Arrhenius equation, IR spectra and a simple 1H NMR line shape analysis, are consistent and in good agreement with experiments in aqueous solution. Based on the presolvation model and the outstanding characteristics of the IR and 1H NMR spectra of the transferring protons, the present theoretical study suggested framework and steps to investigate structural diffusion processes in strong, protonated H-bond systems.

  4. Molecular mechanisms underlying the physiological responses of the cold-water coral Desmophyllum dianthus to ocean acidification

    NASA Astrophysics Data System (ADS)

    Carreiro-Silva, M.; Cerqueira, T.; Godinho, A.; Caetano, M.; Santos, R. S.; Bettencourt, R.

    2014-06-01

    Cold-water corals (CWCs) are thought to be particularly vulnerable to ocean acidification (OA) due to increased atmospheric pCO2, because they inhabit deep and cold waters where the aragonite saturation state is naturally low. Several recent studies have evaluated the impact of OA on organism-level physiological processes such as calcification and respiration. However, no studies to date have looked at the impact at the molecular level of gene expression. Here, we report results of a long-term, 8-month experiment to compare the physiological responses of the CWC Desmophyllum dianthus to OA at both the organismal and gene expression levels under two pCO2/pH treatments: ambient pCO2 (460 ?atm, pHT = 8.01) and elevated pCO2 (997 ?atm, pHT = 7.70). At the organismal level, no significant differences were detected in the calcification and respiration rates of D. dianthus. Conversely, significant differences were recorded in gene expression profiles, which showed an up-regulation of genes involved in cellular stress (HSP70) and immune defence (mannose-binding c-type lectin). Expression of alpha-carbonic anhydrase, a key enzyme involved in the synthesis of coral skeleton, was also significantly up-regulated in corals under elevated pCO2, indicating that D. dianthus was under physiological reconditioning to calcify under these conditions. Thus, gene expression profiles revealed physiological impacts that were not evident at the organismal level. Consequently, understanding the molecular mechanisms behind the physiological processes involved in a coral's response to elevated pCO2 is critical to assess the ability of CWCs to acclimate or adapt to future OA conditions.

  5. Effects of ramp slope on physiological characteristic and performance time of healthy adults propelling and pushing wheelchairs.

    PubMed

    Choi, Young Oh; Lee, Ho Young; Lee, Myoung Hee; Kwon, Oh Hyun

    2015-01-01

    [Purpose] This study examined the effects of ramp slope (1:12, 1:10, 1:8, and 1:6) on physiological characteristics and performance times of wheelchair users and the performance times of caregivers to determine which slope would be the best for wheelchairs, in order to propose a ramp slope that incorporates a universal design. [Subjects and Methods] Twenty-four healthy subjects were enrolled in this study. Fifteen of these subjects also volunteered to participate as caregivers. A wooden ramp with an adjustable slope was constructed. As manual wheelchair users, the participants performed propulsion of a wheelchair up the ramp at a self-selected pace. Four ramp slopes (1:12, 1:10, 1:8, and 1:6) were used, and the participants sequentially ascended them in order from the gentlest to the steepest slope. The caregivers also pushed a wheelchair up the ramp at a self-selected pace. The blood pressure and pulse of participants after the ascent, as well as the performance times of the caregivers and manual wheelchair users, were measured on each of the different ramp slopes. The measured data, pulse, blood pressure, and performance time, were analyzed using repeated ANOVA. [Results] Systolic blood pressure was significantly higher after ascending the 1:6 slope than after ascending the 1:12 and 1:8 slopes. Diastolic blood pressure was significantly higher after ascending the 1:6 slope than after ascending the 1:12 and 1:8 slopes. The participants' pulses tended to increase significantly with an increase in slope. An assessment of the propulsion performance times revealed significant differences among the slopes. [Conclusion] Considering the results of the wheelchair users and caregivers, the 1:12 and 1:10 slopes are suitable ramp slopes for wheelchairs. PMID:25642025

  6. Water Quality Assessment Based on Chemical and Biological Characteristics: An Example of Classification of Characteristics for the Cheremushnyi Creek–Yenisey River Water System

    Microsoft Academic Search

    Z. G. Gol'd; L. A. Glushchenko; I. I. Morozova; S. P. Shulepina; I. A. Shadrin

    2003-01-01

    A six-class scale for a complex classifier of water quality is applied to the Cheremushnyi Creek–Yenisey River water system. The classifier incorporates a chemical index of water pollution and biological characteristics with autotrophic and heterotrophic periphyton groups and macrozoobenthos used as biological indicators. The oligochaeta index and Woodiwiss biotic index are shown to have low indicator capacity. Bioassay studies were

  7. Effects of ecological factors on the survival and physiology of Ralstonia solanacearum bv. 2 in irrigation water.

    PubMed

    van Elsas, J D; Kastelein, P; de Vries, P M; van Overbeek, L S

    2001-09-01

    The fate of Ralstonia solanacearum bv. 2, the causative agent of brown rot in potato, in aquatic habitats of temperate climate regions is still poorly understood. In this study, the population dynamics and the physiological response of R. solanacearum bv. 2 were tested in sterile pure water and in agricultural drainage water obtained from waterways near potato cropping fields in The Netherlands. The behaviour of five different biovar 2 isolates in drainage water at 20 degrees C was very similar among strains. One typical isolate with consistent virulence (strain 1609) was selected for further studies. The effects of temperature, light, canal sediment, seawater salts, and the presence of competing microorganisms on the survival of strain 1609 were assessed. Moreover, the impacts of the physiological state of the inoculum and the inoculum density were analyzed. The population dynamics of strain 1609 in sterile pure water were also characterized. In sterile pure water, the fate of R. solanacearum 1609 cells depended strongly on temperature, irrespective of inoculum density or physiological state. At 4 degrees C and 44 degrees C, strain 1609 CFU numbers showed declines, whereas the strain was able to undergo several cell divisions at 12 degrees C, 20 degrees C, and 28 degrees C. At 20 degrees C and 28 degrees C, repeated growth took place when the organism was serially transferred, at low inoculum density, from grown water cultures into fresh water devoid of nutrients. Both at low and high cell densities and regardless of physiological state, R. solanacearum 1609 cells persisted as culturable cells for limited periods of time in drainage water. A major effect of temperature was found, with survival being maximal at 12 degrees C, 20 degrees C, and 28 degrees C. Temperatures of 4 degrees C, 36 degrees C, or 44 degrees C induced accelerated declines of the culturable cell numbers. The drainage water biota had a strong effect on survival at 12 degrees C, 20 degrees C, and 28 degrees C, as the persistence of strain 1609 was significantly enhanced in sterile drainage water systems. Furthermore, there was a negative effect of incident light, in a light:dark regime, on the survival of R. solanacearum 1609 in natural drainage water. Also, levels of seawater salts realistic for drainage water in coastal areas were detrimental to strain survival. Ralstonia solanacearum 1609 showed considerable persistence in canal sediment saturated with drainage water, but died out quickly when this sediment was subjected to drying. Evidence was obtained for the conversion of R. solanacearum 1609 cells to nonculturable cells in water microcosms kept at 4 degrees C, but not in those kept at 20 degrees C. A substantial fraction of the cells found to be nonculturable were still viable, as evidenced by the direct viable count and by staining with the redox dye 5-cyano-2,3-ditolyl tetrazolium chloride. The potential occurrence of viable-but-nonculturable cells in natural waters poses a problem for the detection of R. solanacearum by cultivation-based methods. PMID:11683466

  8. The Epiphytic Fern Elaphoglossum luridum (Fée) Christ. (Dryopteridaceae) from Central and South America: Morphological and Physiological Responses to Water Stress

    PubMed Central

    Minardi, Bruno Degaspari; Voytena, Ana Paula Lorenzen; Randi, Áurea Maria

    2014-01-01

    Elaphoglossum luridum (Fée) Christ. (Dryopteridaceae) is an epiphytic fern of the Atlantic Forest (Brazil). Anatomical and physiological studies were conducted to understand how this plant responds to water stress. The E. luridum frond is coriaceus and succulent, presenting trichomes, relatively thick cuticle, and sinuous cell walls in both abaxial and adaxial epidermis. Three treatments were analyzed: control, water deficit, and abscisic acid (ABA). Physiological studies were conducted through analysis of relative water content (RWC), photosynthetic pigments, chlorophyll a fluorescence, and malate content. No changes in RWC were observed among treatments; however, significant decreases in chlorophyll a content and photosynthetic parameters, including optimal irradiance (Iopt) and maximum electron transport rate (ETRmax), were determined by rapid light curves (RLC). No evidence of crassulacean acid metabolism (CAM) pathway was observed in E. luridum in response to either water deficit or exogenous application of ABA. On the other hand, malate content decreased in the E. luridum frond after ABA treatment, seeming to downregulate malate metabolism at night, possibly through tricarboxylic acid (TCA) cycle regulation. PMID:25386618

  9. Water-following characteristics of a mixed layer drifter

    NASA Astrophysics Data System (ADS)

    Niller, Pearn P.; Davis, Russ E.; White, Henry J.

    1987-11-01

    Accurate measurements of mean Lagrangian displacements of water parcels in the mixed layer are difficult to make because wave forces on objects that float on or near the ocean surface can be easily rectified to produce a unidirectional motion. Here we discuss a design for an ARGOS-tracked drifter that is configured so as to minimize surface wave effects, and present measurements of its water-following characteristics in the California Current system in July 1985 at 15 m nominal depth in a small range of wind and wave conditions. The unique features of the drifter are small, spherically symmetric, surface and subsurface floats (to reduce directional wave forces) and a large, semi-rigid, three-axis symmetric drogue in the shape of a corner-radar reflector (to reduce kiting in shear) that self-deploys from a folded configuration. Relative 1-2 h mean flows of 0.6-2.9 cm s -1 past the drogue were measured with two vector-measuring current meters (VMCM's) attached to the top and bottom of the drogue in the presence of significant wave heights of 0.3-2.2 m, wind speeds of 2-10 m s -1, and mean vertical shears of 0.34-3.12 × 10 -2s -1. A drag force model shows that the most significant forces in the least square sense are due to winds or surface gravity waves, jointly accounting for 74% of the variance. In July 1985, 20 drogues were released in the vicinity of 31°N, 120°W. Although the encapsuled ARGOS transmitter in the small surface sphere submerged a significant portion of time, an average of 5 out 6 possible ARGOS positions were obtained daily. Recovery and inspection of one drifter both 4 and 8 months after deployment in the California Current revealed the conditions of the mechanical components to be excellent.

  10. Applying additive logistic regression to data derived from sensors monitoring behavioral and physiological characteristics of dairy cows to detect lameness.

    PubMed

    Kamphuis, C; Frank, E; Burke, J K; Verkerk, G A; Jago, J G

    2013-01-01

    The hypothesis was that sensors currently available on farm that monitor behavioral and physiological characteristics have potential for the detection of lameness in dairy cows. This was tested by applying additive logistic regression to variables derived from sensor data. Data were collected between November 2010 and June 2012 on 5 commercial pasture-based dairy farms. Sensor data from weigh scales (liveweight), pedometers (activity), and milk meters (milking order, unadjusted and adjusted milk yield in the first 2 min of milking, total milk yield, and milking duration) were collected at every milking from 4,904 cows. Lameness events were recorded by farmers who were trained in detecting lameness before the study commenced. A total of 318 lameness events affecting 292 cows were available for statistical analyses. For each lameness event, the lame cow's sensor data for a time period of 14 d before observation date were randomly matched by farm and date to 10 healthy cows (i.e., cows that were not lame and had no other health event recorded for the matched time period). Sensor data relating to the 14-d time periods were used for developing univariable (using one source of sensor data) and multivariable (using multiple sources of sensor data) models. Model development involved the use of additive logistic regression by applying the LogitBoost algorithm with a regression tree as base learner. The model's output was a probability estimate for lameness, given the sensor data collected during the 14-d time period. Models were validated using leave-one-farm-out cross-validation and, as a result of this validation, each cow in the data set (318 lame and 3,180 nonlame cows) received a probability estimate for lameness. Based on the area under the curve (AUC), results indicated that univariable models had low predictive potential, with the highest AUC values found for liveweight (AUC=0.66), activity (AUC=0.60), and milking order (AUC=0.65). Combining these 3 sensors improved AUC to 0.74. Detection performance of this combined model varied between farms but it consistently and significantly outperformed univariable models across farms at a fixed specificity of 80%. Still, detection performance was not high enough to be implemented in practice on large, pasture-based dairy farms. Future research may improve performance by developing variables based on sensor data of liveweight, activity, and milking order, but that better describe changes in sensor data patterns when cows go lame. PMID:24011945

  11. Effects of longterm elevated carbon dioxide concentration, nitrogen and water availability on the physiology of loblolly pine (Pinus taeda) branches

    SciTech Connect

    Murthy, R.; Dougherty, P.M. (North Carolina State Univ., Raleigh, NC (United States))

    1994-06-01

    The objective of this study was to determine to what extent elevated CO[sub 2] alters carbon fixation of loblolly pine when water and nutrition are limiting. Three branches per tree were enclosed in polytene chambers and exposed to ambient, 1.5*ambient and 2*ambient levels of CO[sub 2] respectively for a 12 month period. A 2*2 factorial of nutrition and water was employed. Monthly instantaneous measures of maximum photosynthesis (amax), stomatal conductance and other physiological parameters were taken on needles. Branches exposed to 2* ambient CO[sub 2] in the fertilized and irrigated plots showed significantly higher amax values compared to the other treatment level combinations and showed no signs of acclimation. Results suggest that response to elevated CO[sub 2] levels depends greatly on whether nutrition and water are limiting.

  12. Ecohydrology and physiological water relations of vegetation along coastal dune ecotones on subtropical islands

    Microsoft Academic Search

    Tara L. Greaver

    2005-01-01

    As evidence mounts that sea levels are rising, it becomes increasingly important to understand the role of ocean water in the terrestrial hydrology of coastal ecosystems. In coastal dunes, ocean water may enter soils via salt spray through the surface or by ocean water intrusion into deeper vadose layers. However, it is unclear if ocean water enters terrestrial soil of

  13. Structural and physiological responses of two invasive weeds, Mikania micrantha and Chromolaena odorata, to contrasting light and soil water conditions.

    PubMed

    Zhang, Ling-Ling; Wen, Da-Zhi

    2009-01-01

    To better understand the requirement of light and soil water conditions in the invasion sites of two invasive weeds, Mikania micrantha and Chromolaena odorata, we investigated their structural and physiological traits in response to nine combined treatments of light [full, medium and low irradiance (LI)] and soil water (full, medium and low field water content) conditions in three glasshouses. Under the same light conditions, most variables for both species did not vary significantly among different water treatments. Irrespective of water treatment, both species showed significant decreases in maximum light saturated photosynthetic rate (P (max)), photosynthetic nitrogen-use efficiency, and relative growth rate under LI relative to full irradiance; specific leaf area, however, increased significantly from full to LI though leaf area decreased significantly, indicating that limited light availability under extreme shade was the critical factor restricting the growth of both species. Our results also indicated that M. micrantha performed best under a high light and full soil water combination, while C. odorata was more efficient in growth under a high light and medium soil water combination. PMID:19030958

  14. Effects of Drinking Water Temperature on Physiological Responses of Lactating Holstein Cows in Summer1

    Microsoft Academic Search

    J. Ko LANHAM; C. E. Coppock; K. Z. Milam; J. M. Labore; D. H. Nave; R. A. Stermer; C. F. Brasington

    1986-01-01

    Nine Iactating Holstein cows were offered drinking water of 7.2, 15.6, and 23.9°C in a 3 x 3 Latin square design in Experiment 1. Water was offered for 10 min at 1300 h to simulate time in a milking parlor. Water consumption de- clined as drinking water temperature decreased. Respiration rates decreased as the drinking water temperature decreased. In Experiment

  15. Cold-water immersion and other forms of cryotherapy: physiological changes potentially affecting recovery from high-intensity exercise

    PubMed Central

    2013-01-01

    High-intensity exercise is associated with mechanical and/or metabolic stresses that lead to reduced performance capacity of skeletal muscle, soreness and inflammation. Cold-water immersion and other forms of cryotherapy are commonly used following a high-intensity bout of exercise to speed recovery. Cryotherapy in its various forms has been used in this capacity for a number of years; however, the mechanisms underlying its recovery effects post-exercise remain elusive. The fundamental change induced by cold therapy is a reduction in tissue temperature, which subsequently exerts local effects on blood flow, cell swelling and metabolism and neural conductance velocity. Systemically, cold therapy causes core temperature reduction and cardiovascular and endocrine changes. A major hindrance to defining guidelines for best practice for the use of the various forms of cryotherapy is an incongruity between mechanistic studies investigating these physiological changes induced by cold and applied studies investigating the functional effects of cold for recovery from high-intensity exercise. When possible, studies investigating the functional recovery effects of cold therapy for recovery from exercise should concomitantly measure intramuscular temperature and relevant temperature-dependent physiological changes induced by this type of recovery strategy. This review will discuss the acute physiological changes induced by various cryotherapy modalities that may affect recovery in the hours to days (<5 days) that follow high-intensity exercise. PMID:24004719

  16. Influence of arbuscular mycorrhizal fungi on soil structure and soil water characteristics of vertisols

    Microsoft Academic Search

    Birgitte Neergaard Bearden

    2001-01-01

    The influence of inoculation with arbuscular mycorrhizal fungi (AM fungi) on soil water characteristics of fast and slowly wetted vertisol samples was studied. Vertisols characteristically have a low stability to wetting, and the disruption of their larger pores when they swell leads to reduced water infiltration and thereby to runoff. The degree of aggregate breakdown determines the ability of the

  17. Brackish Eutrophic Water Treatment by Iris pseudacorus L.-Planted Microcosms: Physiological Responses of Iris pseudacorus L. to Salinity.

    PubMed

    Zhao, Huilin; Wang, Fen; Ji, Min

    2015-01-01

    Iris pseudacorus L. has been widely used in aquatic ecosystem to remove nutrient and has achieved positive effects. However, little is known regarding the nutrient-removal performance and physiological responses of I. pseudacorus for brackish eutrophic water treatment due to high nutrients combined with certain salinity levels. In this study, I. pseudacorus-planted microcosms were established to evaluate the capacity of I. pseudacorus to remove excessive nutrients from fresh (salinity 0.05%) and brackish (salinity 0.5%) eutrophic waters. The degradation of total nitrogen and ammonia nitrogen were not affected by 0.5% salinity; 0.5% salinity promoted the degradation of nitrate nitrogen while severely inhibited the degradation of total phosphorus. Additionally, 0.5% salinity was found to induce stress responses quantified by measuring six physiological indexes. Compared to 0.05% salinity, 0.5% salinity resulted in significant decreases in the chlorophyll a, b and total chlorophyll contents of I. pseudacorus which closely related to photosynthesis (p < 0.05). Furthermore, the higher proline, malondialdehyde contents and antioxidant enzyme activities were detected in I. pseudacorus exposed to 0.5% salinity, which provided protection against reactive oxygen species. The results highlight that the cellular stress assays are efficient for monitoring the health of I. pseudacorus in salinity shock-associated constructed wetlands. PMID:25529785

  18. Water quality and streamflow characteristics, Raritan River Basin, New Jersey

    USGS Publications Warehouse

    Anderson, Peter W.; Faust, Samuel Denton

    1974-01-01

    The findings of a problem-oriented river-system investigation of the stream-quality and streamflow characteristics of the Raritan River basin (1,105 square miles or 2,862 square kilometers drainage area) are described. The investigation covers mainly the period 1955-72. Precipitation in the basin is classified as ample and averages 47 inches or 120 centimeters per year (3-5 inches or 8-12 centimeters per month). During the study period four general precipitation trends were noted: less than normalin 1955-61 and 1966-70; extreme drought in 1962-66; and above normal in 1971-72. Analyses of streamflow measurements at eight gaging stations indicate a general trend toward lower flows during the study period, which is attributed to generally lower than normal precipitation. Highest flows were observed in 1958, concurrent with maximum annual precipitation; whereas lowest flows were observed in 1965 during extreme drought conditions. Non-tidal streams in the basin are grouped into three general regions of similar chemical quality based upon predominant constituents and dissolved-solids concentration during low-flow conditions. The predominant cations in solution in all regions are calcium and magnesium (usually exceeding 60 percent of total cation content). In headwater streams of the North and South Branch Raritan Rivers, bicarbonate is the predominant anion; a combination of sulfate, chloride, and nitrate are the predominant anions in the other two regions. The dissolved-solids concentration of streams in areas little influenced by man's activities generally range from 40 to 200 mg/L. Those in areas influenced by man often range much higher sometimes exceeding 800 mg/L. Suspended-sediment yields in the basin range from 25 to 500 tons per square mile annually. The water quality of the Raritan River and most tributaries above Manville (784 square miles of 2,030 square kilometers drainage area) generally is good for most industrial, domestic, and recreational uses, although pollution has been reported locally in some areas. A comparison of chemical analyses of water collected at several sampling sites in the 1920's with more recent data, however, indicate that there has been a significant increase in sulfate, chloride, and nitrate ions transported per unit of streamflow. These increases reflect increased waste-water discharges and nutrients in agricultural runoff in the upper basin. Trends in the dissolved-solids and dissolved-oxygen concentation of water in the Raritan and MIllstone Rivers above their confluence at Manville are described. The dissolved solids of the Millstone River are shown to increase, particularly at low streamflows. For example, at a flow of 100 cubic feet per second (2.83 cubic meters per second) this river tansported 13 percent more dissolved solids in 1969-70 than it did in 1957-58. A similar trend, however, was not apparent on the Raritan River. This phenomenon is attributed to dilution provided since 1964 by upstream reservoir releases during low flows. With the exception of low-flow periods on the Raritan River, dissolved-oxygen concentrations showed little or no significant time trends at Manville on either the Raritan or Millstone River. An improvement in dissolved-oxygen content at flows lower than 100 cubic feet per second (2.83 cubic meters per second) is observed with time on the Raritan River. This improvement is attributed to generally better quality water and dilution of nonconservative pollutants by upstream reservoir releases during low flows. The Raritan River between Manville and Perth Amboy flows through a large urban and industrial complex. Much of this reach is tidal. Detrimental activities of man are reflected in higher concentrations of most constituents below Manville than those observed upstream. For example, between Manville and the head of tide near South Bound Brook, the maximum concentration of dissolved solids observed during the study period increased from 464 to 1,520 mg/L; orthophosphates from 0.93 to 2.3 mg/L; phenolic materials from 22 to 312 ?g/L; and coliform bacteria

  19. Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?

    PubMed

    Durban, J W; Pitman, R L

    2012-04-23

    Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h(-1), 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30-37° S) off Uruguay and Brazil, in surface water temperatures ranging from -1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales. PMID:22031725

  20. [Spectral characteristics analysis and remote sensing inversion of water quality parameters in Han Shiqiao wetland].

    PubMed

    Du, Wei-Jing; Li, Shu-Min; Li, Hong; Sun, Dan-Feng; Zhou, Lian-Di

    2010-03-01

    The research object of the present paper is the water quality of Han Shiqiao wetland water. Water spectrum and quality parameters were measured on the site and in the lab. The authors simulated the relationships between water quality parameters and the best bands or combination, and built the multiple linear regression equation to obtain characteristic spectrum of the key water quality parameters. Besides, several key issues involved in applying ASTER satellite imagery to water quality include atmospheric correction, discussing methods for ASTER data bands analysis, and choosing the best bands and band combination. Results indicated that although the simulation model is not universal, the analysis of spectral characteristics based on ground spectrometer could provide foundations for the choice of remote sensing characteristics bands. The band ratio of water quality parameters simulated from ASTER spectral characteristics moves to relatively long-wave band. Finally, based on the analysis of ASTER remote sensing characteristics bands, the authors built water quality parameters regression model. The models for water quality parameters were recommended, and the accuracies of these models were analyzed. Making use of regression model, we executed spatial distribution map of water quality parameters to achieve wetland water monitoring with remote sensing in terms of variation in space and with time. PMID:20496703

  1. Physiological effects

    SciTech Connect

    Pearcy, R.W.; Bjoerkman, O.

    1983-01-01

    This chapter examines the effects of CO/sub 2/ on plants at the physiological level. The authors examine the potential effects of elevated CO/sub 2/ in concert with water, temperature, light, and salinity. They also examine plant allometric growth as it is affected by CO/sub 2/. The relationships between CO/sub 2/ uptake and temperature are examined in some detail. Stomatal function as it is now known is discussed, along with changes in water use efficiency correlated with increased levels of CO/sub 2/. Future research needs are identified. 71 references, 8 figures.

  2. Characteristic Analysis of Water Heater-Chiller Unit Driven by Natural-gas Engine

    Microsoft Academic Search

    Zhao Yang; Haibo Zhao; Xihong Li

    2005-01-01

    Experimental researche was carried out on the installation, refit and running of a water heater-chiller unit of a water-to-water heat pump driven by a natural-gas engine to test the running characteristics of the engine, the performance characteristics of the heat pump, and the overall system. The results show that the heat pump unit driven by a natural-gas engine (GEHP) is

  3. Combined effects of nitrogen deposition and water stress on growth and physiological responses of two annual desert plants in northwestern China

    Microsoft Academic Search

    Xiaobing Zhou; Yuanming Zhang; Xuehua Ji; Alison Downing; Marcelo Serpe

    2011-01-01

    Two annual desert plants, Malcolmia africana (L.) R.Br. (Brassicaceae) and Bassia hyssopifolia (Pall.) Kuntz (Chenopodiaceae) were selected to determine the combined effects of nitrogen deposition and water stress on their growth and physiological responses. Nitrogen addition and water stress significantly affected growth of both species. Root weight, leaf number, average leaf area, total biomass, and the shoot\\/root ratio increased with

  4. Molecular Mechanism of Water and Gas Transport Across Biological Membranes and Consequences for Plant Physiology

    Microsoft Academic Search

    Norbert Uehlein

    \\u000a Aquaporins are membrane proteins, facilitating the transport of water across biological membranes. At the time of their discovery,\\u000a biological membranes were thought to be that permeable for water, that there was no need for proteins facilitating membrane\\u000a water transport. In fact, the demonstration of aquaporin function was so groundbreaking, that in 2003 the Nobel Prize for\\u000a Chemistry was awarded to

  5. Anatomic and functional characteristics of a slow posterior A V nodal pathway: role in dual-pathway physiology and reentry

    Microsoft Academic Search

    Djamila Medkour; Anton E. Becker; Karim Khalife; Jacques Billette

    1998-01-01

    Background—The AV node is frequently the site of reentrant rhythms. These rhythms arise from a slow and a fast pathway for which the anatomic and functional substratum remain debated. This study proposes a new explanation for dual-pathway physiology in which the posterior nodal extension (PNE) provides the substratum for the slow pathway. Methods and Results—The anatomic and functional properties of

  6. Effect of Salinity on Biomass Yield and Physiological and Stem-Root Anatomical Characteristics of Purslane (Portulaca oleracea L.) Accessions

    PubMed Central

    Juraimi, Abdul Shukor; Rafii, M. Y.; Abdul Hamid, Azizah

    2015-01-01

    13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32?dS?m?1. Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P < 0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16?dS?m?1 salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8?dS?m?1 salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession. PMID:25802833

  7. Effect of salinity on biomass yield and physiological and stem-root anatomical characteristics of purslane (Portulaca oleracea L.) accessions.

    PubMed

    Alam, Md Amirul; Juraimi, Abdul Shukor; Rafii, M Y; Abdul Hamid, Azizah

    2015-01-01

    13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32 dS m(-1). Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P < 0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16 dS m(-1) salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8 dS m(-1) salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession. PMID:25802833

  8. Physiological and behavioral responses to different watering intervals in lactating camels (Camelus dromedarius).

    PubMed

    Bekele, Tafesse; Olsson, Kerstin; Olsson, Ulf; Dahlborn, Kristina

    2013-09-15

    During drought periods camels are watered at long intervals, but effects on body fluid homeostasis of lactating camels are not known. It was hypothesized that camels store water after drinking and minimize water losses by diurnal variation in body temperature, changes in behavior, and release of vasopressin. The aim was to find a sustainable watering interval for lactating camels. Seven lactating camels were studied in a cross-over trial in which they were watered once daily (W1), every fourth day (W4), every eighth day (W8), or after 16 days (W16) with a 5-day interval between treatments. When offered water every fourth or eighth days, the camels drank sufficient amounts to cover their needs for subsequent days, but after 16 days of dehydration they did not drink enough to compensate the body weight loss. Rectal temperature fell at night and the camels searched shade during daytime minimizing evaporative fluid losses. Plasma osmolality and sodium concentration were elevated after 4 days of water deprivation and plasma protein and vasopressin concentrations after 8 days. Milk production decreased during the last week of W16. Plasma aldosterone concentration was elevated upon rehydration after W16, indicating sodium deficiency. In conclusion, lactating camels stored water after drinking and reduced water losses by staying in shade, keeping body temperature low, and releasing plasma vasopressin. However, serious dehydration was observed during W8, and after 16 days of water deprivation recovery took a long time. A watering interval between 4 and 7 days seems advisable under similar environmental conditions. PMID:23842680

  9. Azospirillum and arbuscular mycorrhizal colonization enhance rice growth and physiological traits under well-watered and drought conditions.

    PubMed

    Ruíz-Sánchez, Michel; Armada, Elisabet; Muñoz, Yaumara; García de Salamone, Inés E; Aroca, Ricardo; Ruíz-Lozano, Juan Manuel; Azcón, Rosario

    2011-07-01

    The response of rice plants to inoculation with an arbuscular mycorrhizal (AM) fungus, Azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. Water deficit treatment was imposed by reducing the amount of water added, but AM plants, with a significantly higher biomass, received the same amount of water as non-AM plants, with a poor biomass. Thus, the water stress treatment was more severe for AM plants than for non-AM plants. The results showed that AM colonization significantly enhanced rice growth under both water conditions, although the greatest rice development was reached in plants dually inoculated under well-watered conditions. Water level did not affect the efficiency of photosystem II, but both AM and A. brasilense inoculations increased this value. AM colonization increased stomatal conductance, particularly when associated with A. brasilense, which enhanced this parameter by 80% under drought conditions and by 35% under well-watered conditions as compared to single AM plants. Exposure of AM rice to drought stress decreased the high levels of glutathione that AM plants exhibited under well-watered conditions, while drought had no effect on the ascorbate content. The decrease of glutathione content in AM plants under drought stress conditions led to enhance lipid peroxidation. On the other hand, inoculation with the AM fungus itself increased ascorbate and proline as protective compounds to cope with the harmful effects of water limitation. Inoculation with A. brasilense also enhanced ascorbate accumulation, reaching a similar level as in AM plants. These results showed that, in spite of the fact that drought stress imposed by AM treatments was considerably more severe than non-AM treatments, rice plants benefited not only from the AM symbiosis but also from A. brasilense root colonization, regardless of the watering level. However, the beneficial effects of A. brasilense on most of the physiological and biochemical traits of rice plants were only clearly visible when the plants were mycorrhized. This microbial consortium was effective for rice plants as an acceptable and ecofriendly technology to improve plant performance and development. PMID:21377754

  10. The Influence Of Water Tracks And Hillslope Position On The Physiology Of The Dominant Plant Species In The Imnavait Creek Watershed, Alaska

    NASA Astrophysics Data System (ADS)

    Griffin, K. L.; Epstein, D. J.; Shapiro, J. B.; Boelman, N. T.; Stieglitz, M.

    2003-12-01

    Within a small arctic tundra watershed located on the north slope of Alaska, we asked if plant abundance and physiological performance are linked to hillslope position by the hydrologic processes controlling nutrient availability. Our prediction was that down slope sites and within water track sites should have the greatest nutrient availability resulting in the highest photosynthetic capacity and productivity. To examine these relationships, two transects were established in the Imnavait Creek watershed, running from the northern ridge crest to a beaded stream. In total, 16 sites, one water track (WT) and one non water track (NWT), from 8 locations, each 100 m apart were examined. At each site, soil moisture, thaw depth, canopy water status (from spectral reflectance) and species diversity were recorded. Chlorophyll fluorescence was used assess the maximum capacity of each species to transport electrons within the photosynthetic membranes of individual leaves (ETRMAX), a variable we expect to reflect both leaf N and general photosynthetic capacity. Significant differences were found within and among the major functional groups of plants growing in the watershed. In the two deciduous shrubs, Betula nana and Salix pulchra, ETRMAX generally decreased down slope but no significant difference were found between the WT and NWT sites. By contrast, ETRMAX in Rubus chamaemors, also a deciduous species, showed an initial decrease at the first two locations, but then remained constant further down slope and between WT and NWT sites. In the evergreen plants, Ledum palustre differed in that the maximum ETRMAX was found at the mid-slope locations while Vaccinium vitis-idaea had a characteristic decrease in ETRMAX down slope, with a large difference between WT and NWT at the first location. The forb Petasites frigidus displayed a unique pattern, with large difference in ETRMAX between WT and NWT at sites 4 and 5, the last two locations at which this species could be found. Finally, the only graminoid species studied, Eriophorum vaginatu, ETRMAX decrease down slope in a linear fashion and had the highest absolute ETRMAX. Additionally leaf gas-exchange was measured in Salix pulchra and leaf N and canopy reflectance was measured at each site. Together, our results demonstrate that while hillsope position has a significant effect on the physiology, growth and diversity of species, the relationships were not as hypothesized. Clearly other ecological, morphological or environmental factors are contributing to the productivity of the watershed and ultimately impacting the biogeochemistry of this important ecosystem.

  11. Flammability characteristics of sprays of water-based paints

    Microsoft Academic Search

    Ulrich von Pidoll; Helmut Krämer

    1997-01-01

    Mainly in the car industry, many automatic electrostatic spraying installations are at present being converted to use water-based paints. This will involve considerable advantages in the field of fire and explosion protection, if the water-based paints used can be considered non flammable when sprayed. To investigate this question, the burning behaviour of more than 120 electrostatically sprayed water-based paints, which

  12. Effect of Groove Location on the Dynamic Characteristics of Multiple Axial Groove Water Lubricated Journal Bearing

    Microsoft Academic Search

    M. Vijaya Kini; R. S. Pai; D. Srikanth Rao; Satish Shenoy B

    2009-01-01

    The stability characteristics of water lubricated journal bearings having three axial grooves are obtained theoretically. In this lubricant (water) is fed under pressure from one end of the bearing, through the 3-axial grooves (groove angles may vary). These bearings can use the process fluid as the lubricant, as in the case of feed water pumps. The Reynolds equation is solved

  13. Water flux and osmoregulatory physiology of the West Indian Manatee (Trichechus manatus) 

    E-print Network

    Ortiz, Rudy Martin

    1994-01-01

    in fresh and salt water, as well as in wild animals in fresh, brackish, and salt water to examine the mechanisms these animals employ for proper osmoregulation. Responses of these systems to changes in salinity were evaluated by switching four animals...

  14. Thermophysical characteristics of water-in-FC72 nanoemulsion fluids

    NASA Astrophysics Data System (ADS)

    Han, Z. H.; Yang, B.

    2008-01-01

    The use of solid particles has long been a common way of increasing fluid thermal conductivity. Here, nanoemulsion fluids—dispersions of liquid nanodroplets—are proposed. As an example, water-in-FC72 nanoemulsion fluids are developed, and their thermophysical properties and impact on natural convective heat transfer are investigated experimentally. The increase in conductivity and viscosity of the fluids is found to be nonlinear with water loading, indicating an important role of the hydrodynamic interaction and aggregation of nanodroplets. A very remarkable increase in effective specific heat—about 126% for 12vol% water loading—occurs in the fluids due to melting-freezing transition of water nanodroplets.

  15. Morphological and physiological responses of two coffee progenies to soil water availability.

    PubMed

    Dias, Paulo C; Araujo, Wagner L; Moraes, Gustavo A B K; Barros, Raimundo S; DaMatta, Fábio M

    2007-12-01

    Drought is a major environmental constraint affecting growth and production of coffee. The effects of water supply on growth, biomass allocation, water relations, and gas exchange in two coffee progenies representing drought-tolerant (Siriema) and drought-sensitive (Catucaí) genotypes were compared. They were grown in 12-L pots until 4-months old, when they were submitted to two watering treatments for 60 d: plants receiving either 100% transpired water (control plants) or a fraction (about 40%) of the amount of water transpired by control plants (drought-stressed plants). Under control conditions, Siriema grew faster than Catucaí. Regardless of the watering regimes and progenies, relative growth rate (RGR) was positively correlated both with net assimilation rate (NAR) and long-term water-use efficiency (WUE), but not with differences in biomass allocation. Both progenies responded to drought stress through (i) similar decreases in both RGR and NAR with marginal, if any, changes in allocation; (ii) decreases in leaf water potential, which occurred to a greater extent in Catucaí than in Siriema, even though they have showed similar abilities to adjust osmotically and elastically; (iii) similar reductions in net photosynthesis due mainly to nonstomatal factors; and (iv) decreases in transpiration rate coupled with increased long-term WUE. However, the lower transpiration rate and the higher long-term WUE as found in Siriema relative to Catucaí under control conditions persisted under drought conditions. Overall, the major differences between these progenies were largely associated with differences in plant water use, which was likely related to the improved water status of Siriema. The possible implications of selecting coffee genotypes for high WUE are discussed. PMID:17291628

  16. Physiologically Based Pharmacokinetic modeling of the temperature-dependent dermal absorption of chloroform by humans following bath water exposures

    SciTech Connect

    Corley, Rick A.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Gordon, Syd M.(Battelle Memorial Institute) [Battelle Memorial Institute; Wallace, Lance A.(U.S. Environmental Protection Agency) [U.S. Environmental Protection Agency

    2000-01-14

    The kinetics of chloroform in the exhaled breath of human volunteers exposed skin-only via bath water (concentrations < 100 ppb) were analyzed using a physiologically based pharmacokinetic (PBPK) model. Significant increases in exhaled chloroform (and thus bioavailability) were observed as exposure temperatures were increased from 30 to 40?C. The blood flows to the skin and effective skin permeability coefficients (Kp) were both varied to reflect the temperature-dependent changes in physiology and exhalation kinetics. At 40?C, no differences were observed between males and females. Therefore, Kp?s were determined ({approx}0.06 cm/hr) at a skin blood flow rate of 18% of the cardiac output. At 30 and 35?C, males exhaled more chloroform than females resulting in lower effective Kp?s calculated for females. At these lower temperatures, the blood flow to the skin was also reduced. Total amounts of chloroform absorbed averaged 41.9 and 43.6 mg for males and 11.5 and 39.9 mg for females exposed at 35 and 40?C, respectively. At 30?C, only 2/5 males and 1/5 females had detectable concentrations of chloroform in their exhaled breath. For perspective, the total intake of chloroform would have ranged from 79 - 194 mg if the volunteers had consumed 2 L of water orally at the concentrations used in this study. Thus, the relative contribution of dermal uptake of chloroform to the total body burdens associated with bathing for 30 min and drinking 2 L of water (ignoring contributions from inhalation exposures) was predicted to range from 1-28% depending on the temperature of the bath.

  17. Spatiotemporal characteristics and water budget of water cycle elements in different seasons in northeast China

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Zhao, Jun-Hu; He, Wen-Ping; Zhi-Qiang, Gong

    2015-04-01

    In this paper, we study the spatiotemporal characteristics of precipitable water, precipitation, evaporation, and water–vapor flux divergence in different seasons over northeast China and the water balance of that area. The data used in this paper is provided by the European Center for Medium-Range Weather Forecasts (ECMWF). The results show that the spatial distributions of precipitable water, precipitation, and evaporation feature that the values of elements above in the southeastern area are larger than those in the northwestern area; in summer, much precipitation and evaporation occur in the Changbai Mountain region as a strong moisture convergence region; in spring and autumn, moisture divergence dominates the northeast of China; in winter, the moisture divergence and convergence are weak in this area. From 1979 to 2010, the total precipitation of summer and autumn in northeast China decreased significantly; especially from 1999 to 2010, the summer precipitation always demonstrated negative anomaly. Additionally, other elements in different seasons changed in a truly imperceptible way. In spring, the evaporation exceeded the precipitation in northeast China; in summer, the precipitation was more prominent; in autumn and winter, precipitation played a more dominating role than the evaporation in the northern part of northeast China, while the evaporation exceeded the precipitation in the southern part. The Interim ECMWF Re-Analysis (ERA-Interim) data have properly described the water balance of different seasons in northeast China. Based on ERA-Interim data, the moisture sinks computed through moisture convergence and moisture local variation are quite consistent with those computed through precipitation and evaporation, which proves that ERA-Interim data can be used in the research of water balance in northeast China. On a seasonal scale, the moisture convergence has a greater influence than the local moisture variation on a moisture sink, and the latter is variable slightly, generally as a constant. Likewise, in different seasons, the total precipitation has a much greater influence than the evaporation on the moisture sink. Project supported by the State Key Development Program for Basic Research of China (Grant Nos. 2013CB430204 and 2012CB955902) and the National Natural Science Foundation of China (Grant Nos. 41175067, 41175084, and 41205040).

  18. Deficit Irrigation Effects on Water Use Characteristics of Bentgrass Species

    Microsoft Academic Search

    Michelle DaCosta; Bingru Huang

    2006-01-01

    This study was designed to determine the effects of deficit irrigation on water use traits of colonial (Agrostis capillaris L.), creeping (A. stolonifera L.), and velvet (A. canina L.) bentgrasses and to compare their water use. Field experiments were conducted from July to November in 2002 and 2003. Plots were irrigated at four levels of irrigation based on the percentage

  19. Characteristics of the absorbed dose to water standard at ENEA

    NASA Astrophysics Data System (ADS)

    Guerra, A. S.; Laitano, R. F.; Pimpinella, M.

    1996-04-01

    The primary standard of absorbed dose to water established at ENEA for the Co-60 gamma-ray quality is based on a graphite calorimeter and an ionometric transfer system. This standard was recently improved after a more accurate assessment of some perturbation effects in the calorimeter and a modification of the water phantom shape and size. The conversion procedure requires two corresponding depths, one in graphite and one in water, where the radiation energy spectra must be the same. The energy spectra at the corresponding points were determined by a Monte Carlo simulation in water and graphite scaled phantoms. A thorough study of the calorimeter gap effect corrections was also made with regard to their dependence on depth and field size. A comparison between the ionization chamber calibration procedures based on the standards of absorbed dose to water and of air kerma was also made, confirming the consistency of the two methods.

  20. Optical characteristics of natural waters protect amphibians from UV-B in the U.S. Pacific Northwest

    USGS Publications Warehouse

    Palen, Wendy J.; Schindler, David E.; Adams, Michael J.; Pearl, Christopher A.; Bury, R. Bruce; Diamond, S.A.

    2002-01-01

    Increased exposure to ultraviolet-B (UV-B) radiation has been proposed as a major environmental stressor leading to global amphibian declines. Prior experimental evidence from the U.S. Pacific Northwest (PNW) indicating the acute embryonic sensitivity of at least four amphibian species to UV-B has been central to the literature about amphibian decline. However, these results have not been expanded to address population-scale effects and natural landscape variation in UV-B transparency of water at amphibian breeding sites: both necessary links to assess the importance of UV-B for amphibian declines. We quantified the UV-B transparency of 136 potential amphibian breeding sites to establish the pattern of UV-B exposure across two montane regions in the PNW. Our data suggest that 85% of sites are naturally protected by dissolved organic matter in pond water, and that only a fraction of breeding sites are expected to experience UV-B intensities exceeding levels associated with elevated egg mortality. Thus, the spectral characteristics of natural waters likely mediate the physiological effects of UV-B on amphibian eggs in all but the clearest waters. These data imply that UV-B is unlikely to cause broad amphibian declines across the landscape of the American Northwest.

  1. Facing the River Gauntlet: Understanding the Effects of Fisheries Capture and Water Temperature on the Physiology of Coho Salmon

    PubMed Central

    Raby, Graham D.; Clark, Timothy D.; Farrell, Anthony P.; Patterson, David A.; Bett, Nolan N.; Wilson, Samantha M.; Willmore, William G.; Suski, Cory D.; Hinch, Scott G.; Cooke, Steven J.

    2015-01-01

    An improved understanding of bycatch mortality can be achieved by complementing field studies with laboratory experiments that use physiological assessments. This study examined the effects of water temperature and the duration of net entanglement on physiological disturbance and recovery in coho salmon (Oncorhynchus kisutch) after release from a simulated beach seine capture. Heart rate was monitored using implanted electrocardiogram biologgers that allowed fish to swim freely before and after release. A subset of fish was recovered in respirometers to monitor metabolic recovery, and separate groups of fish were sacrificed at different times to assess blood and white muscle biochemistry. One hour after release, fish had elevated lactate in muscle and blood plasma, depleted tissue energy stores, and altered osmoregulatory status, particularly in warmer (15 vs. 10°C) and longer (15 vs. 2 min) capture treatments. A significant effect of entanglement duration on blood and muscle metabolites remained after 4 h. Oxygen consumption rate recovered to baseline within 7–10 h. However, recovery of heart rate to routine levels was longer and more variable, with most fish taking over 10 h, and 33% of fish failing to recover within 24 h. There were no significant treatment effects on either oxygen consumption or heart rate recovery. Our results indicate that fishers should minimize handling time for bycatch and maximize oxygen supply during crowding, especially when temperatures are elevated. Physiological data, such as those presented here, can be used to understand mechanisms that underlie bycatch impairment and mortality, and thus inform best practices that ensure the welfare and conservation of affected species. PMID:25901952

  2. Effects of environmental parameters, leaf physiological properties and leaf water relations on leaf water delta18O enrichment in different Eucalyptus species.

    PubMed

    Kahmen, Ansgar; Simonin, Kevin; Tu, Kevin P; Merchant, Andrew; Callister, Andrew; Siegwolf, Rolf; Dawson, Todd E; Arndt, Stefan K

    2008-06-01

    Stable oxygen isotope ratios (delta18O) have become a valuable tool in the plant and ecosystem sciences. The interpretation of delta18O values in plant material is, however, still complicated owing to the complex interactions among factors that influence leaf water enrichment. This study investigated the interplay among environmental parameters, leaf physiological properties and leaf water relations as drivers of the isotopic enrichment of leaf water across 17 Eucalyptus species growing in a common garden. We observed large differences in maximum daily leaf water delta18O across the 17 species. By fitting different leaf water models to these empirical data, we determined that differences in leaf water delta18O across species are largely explained by variation in the Péclet effect across species. Our analyses also revealed that species-specific differences in transpiration do not explain the observed differences in delta18O while the unconstrained fitting parameter 'effective path length' (L) was highly correlated with delta18O. None of the leaf morphological or leaf water related parameters we quantified in this study correlated with the L values we determined even though L was typically interpreted as a leaf morphological/anatomical property. A sensitivity analysis supported the importance of L for explaining the variability in leaf water delta18O across different species. Our investigation highlighted the importance of future studies to quantify the leaf properties that influence L. Obtaining such information will significantly improve our understanding of what ultimately determines the delta18O values of leaf water across different plant species. PMID:18208514

  3. Growth and physiological responses of tree seedlings to experimental manipulation of light and water

    SciTech Connect

    Huston, M.A.; Holmgren, M. [Oak Ridge National Lab., TN (United States)

    1995-06-01

    Seedlings of two tree species with similar tolerance to soil water and nutrient levels, but contrasting tolerance to shade (Acer saccharum and Liriodendron tulipifera) were grown in shade houses under 5 light levels (27%, 17%, 12%, 5%, and 1%) and three soil water regimes (5-9%, 11-15%, and >20%). Soil, light, and water conditions were representative of those in the Walker Branch Throughfall Displacement Experiment, where the same species are being monitored under field conditions. Treatments were maintained from mid-June through October, when all plants were harvested for determination of biomass allocation patterns. The only mortality occurred among the tulip poplars, but there was a significant interaction effect of the treatments on leaf area, total biomass, and allocation patterns. Highest growth rates in both species occurred at 17% light in the highest water treatment, with the 27% treatment showing reduced growth, perhaps due to photoinhibition. Gas exchange measurements indicated that the light compensation point increased under dry conditions.

  4. Herpetological diversity along Andean elevational gradients: links with physiological ecology and evolutionary physiology.

    PubMed

    Navas, Carlos A

    2002-11-01

    A well-defined macroecological pattern is the decline in biodiversity with altitude. However, this decline is taxa-specific. For example, amphibians are more diverse than squamates at extreme elevations in the tropical Andes, but this pattern is reversed at extreme elevations in the southern latitudes. Several ecophysiological and evolutionary factors may be related to this difference. At high-elevations in southern latitudes temperature differs dramatically among seasons and dry soils dominate, characteristics that appear to favor lizard physiological ecology. Tropical high altitudes, in contrast, are humid and offer abundant and diverse water resources. These characteristics allow for a richer anuran community but might complicate lizard egg development through temperature and oxygen constrains. Differences in strategies of thermal adaptation might also modulate diversity patterns. The thermal physiology of anurans is extremely labile so that behavioral and physiological performance is maintained despite an altitudinal decrease in field body temperature. Lizards, in contrast, exhibit a conservative thermal physiology and rely on behavioral thermoregulation to face cold and variable temperatures. Both, lizard behavioral strategies and anuran physiological adjustments seem equally efficient in allowing ecological success and diversification for both groups in the tropics up to approximately 3000 m. At higher elevations physiological thermal adaptation is required, and lizards are ecologically constrained, perhaps at various ontogenetic stages. Patterns of biodiversity along environmental clines can be better understood through a physiological approach, and can help to refine and propose hypotheses in evolutionary physiology. PMID:12443907

  5. Water Use Efficiency and Physiological Response of Rice Cultivars under Alternate Wetting and Drying Conditions

    PubMed Central

    Zhang, Yunbo; Tang, Qiyuan; Peng, Shaobing; Xing, Danying; Qin, Jianquan; Laza, Rebecca C.; Punzalan, Bermenito R.

    2012-01-01

    One of the technology options that can help farmers cope with water scarcity at the field level is alternate wetting and drying (AWD). Limited information is available on the varietal responses to nitrogen, AWD, and their interactions. Field experiments were conducted at the International Rice Research Institute (IRRI) farm in 2009 dry season (DS), 2009 wet season (WS), and 2010 DS to determine genotypic responses and water use efficiency of rice under two N rates and two water management treatments. Grain yield was not significantly different between AWD and continuous flooding (CF) across the three seasons. Interactive effects among variety, water management, and N rate were not significant. The high yield was attributed to the significantly higher grain weight, which in turn was due to slower grain filling and high leaf N at the later stage of grain filling of CF. AWD treatments accelerated the grain filling rate, shortened grain filling period, and enhanced whole plant senescence. Under normal dry-season conditions, such as 2010 DS, AWD reduced water input by 24.5% than CF; however, it decreased grain yield by 6.9% due to accelerated leaf senescence. The study indicates that proper water management greatly contributes to grain yield in the late stage of grain filling, and it is critical for safe AWD technology. PMID:23319883

  6. Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption

    PubMed Central

    Boone, Michelle

    2008-01-01

    To prevent dehydration, terrestrial animals and humans have developed a sensitive and versatile system to maintain their water homeostasis. In states of hypernatremia or hypovolemia, the antidiuretic hormone vasopressin (AVP) is released from the pituitary and binds its type-2 receptor in renal principal cells. This triggers an intracellular cAMP signaling cascade, which phosphorylates aquaporin-2 (AQP2) and targets the channel to the apical plasma membrane. Driven by an osmotic gradient, pro-urinary water then passes the membrane through AQP2 and leaves the cell on the basolateral side via AQP3 and AQP4 water channels. When water homeostasis is restored, AVP levels decline, and AQP2 is internalized from the plasma membrane, leaving the plasma membrane watertight again. The action of AVP is counterbalanced by several hormones like prostaglandin E2, bradykinin, dopamine, endothelin-1, acetylcholine, epidermal growth factor, and purines. Moreover, AQP2 is strongly involved in the pathophysiology of disorders characterized by renal concentrating defects, as well as conditions associated with severe water retention. This review focuses on our recent increase in understanding of the molecular mechanisms underlying AVP-regulated renal water transport in both health and disease. PMID:18431594

  7. Oxygen flux as an indicator of physiological stress in aquatic organisms: a real-time biomonitoring system of water quality

    NASA Astrophysics Data System (ADS)

    Sanchez, Brian C.; Yale, Gowri; Chatni, Rameez; Ochoa-Acuña, Hugo G.; Porterfield, D. Marshall; Mclamore, Eric S.; Sepúlveda, María S.

    2009-05-01

    The detection of harmful chemicals and biological agents in real time is a critical need for protecting water quality. We studied the real-time effects of five environmental contaminants with differing modes of action (atrazine, pentachlorophenol, cadmium chloride, malathion, and potassium cyanide) on respiratory oxygen consumption in 2-day post-fertilization fathead minnow (Pimephales promelas) eggs. Our objective was to assess the sensitivity of fathead minnow eggs using the self-referencing micro-optrode technique to detect instantaneous changes in oxygen consumption after brief exposures to low concentrations of contaminants. Oxygen consumption data indicated that the technique is indeed sensitive enough to reliably detect physiological alterations induced by all contaminants. After 2 h of exposure, we identified significant increases in oxygen consumption upon exposure to pentachlorophenol (100 and 1000 ?g/L), cadmium chloride (0.0002 and 0.002 ?g/L), and atrazine (150 ?g/L). In contrast, we observed a significant decrease in oxygen flux after exposures to potassium cyanide (5.2, 22, and 44 ?g/L) and atrazine (1500 ?g/L). No effects were detected after exposures to malathion (200 and 340 ?g/L). We have also tested the sensitivity of Daphnia magna embryos as another animal model for real-time environmental biomonitoring. Our results are so far encouraging and support further development of this technology as a physiologically coupled biomonitoring tool for the detection of environmental toxicants.

  8. OCCURRENCE OF HETEROTROPHIC BACTERIA WITH VIRULENCE CHARACTERISTICS IN POTABLE WATER

    EPA Science Inventory

    Treated potable water contains a variety of heterotrophic bacteria that survive current treatment processes. There is evidence that these bacteria are not hazardous to the healthy population, however, the possibility exists that some of them may be opportunistic pathogens capabl...

  9. DEVELOPING JOINT PROBABILITY DISTRIBUTIONS OF SOIL WATER RETENTION CHARACTERISTICS

    EPA Science Inventory

    A method is presented for developing probability density functions for parameters of soil moisture relationships of capillary head and hydraulic conductivity. These soil moisture parameters are required for the assessment of water flow and solute transport in unsaturated media. T...

  10. Effects of temperature and light intensity on growth and physiology in purple root water hyacinth and common water hyacinth (Eichhornia crassipes).

    PubMed

    Shu, Xiao; Zhang, QuanFa; Wang, WeiBo

    2014-11-01

    In this study, the interaction between temperature and light intensity was investigated in common water hyacinth (CWH) and purple root water hyacinth (PRWH). Effects of different temperatures (11/5, 18/11, 25/18, and 32/25 °C day/night) simultaneously applied at various light intensities (100, 300, and 600 ?mol m(-2) s(-1)) to the plants were detected by measuring changes in the root lengths, protein content, sugar content, malondialdehyde (MDA) content, photosynthesis, and dissolved oxygen (DO). Temperature and light intensity significantly influence the growth of water hyacinths, and there was significant interaction among these environmental factors. The results suggest that several environmental factors act synergistically on the growth and physiology of water hyacinths. The higher new root length (NRL) in PRWH indicated that its root growth capacity is higher than in CWH. The soluble sugar content in leaves of CWH was higher than PRWH, indicating that relatively higher sugar content in CWH to low-temperature stress may support its tolerant nature. Lower temperature and light intensity can stimulate the accumulation of MDA content. The net photosynthetic rate (Pn) in leaves of CWH was higher than PRWH. In low temperature, increase light intensity can stimulate the Pn of PRWH and CWH. In CWH and PRWH, Pn showed a similar trend as noted for stomatal conductance (Cond) and transpiration rate (Tr). The capacity of PRWH in adding oxygen to the water column is better than those of CWH. PMID:24994106

  11. Physiology and proteomics of the water-deficit stress response in three contrasting peanut genotypes.

    PubMed

    Kottapalli, Kameswara Rao; Rakwal, Randeep; Shibato, Junko; Burow, Gloria; Tissue, David; Burke, John; Puppala, Naveen; Burow, Mark; Payton, Paxton

    2009-04-01

    Peanut genotypes from the US mini-core collection were analysed for changes in leaf proteins during reproductive stage growth under water-deficit stress. One- and two-dimensional gel electrophoresis (1- and 2-DGE) was performed on soluble protein extracts of selected tolerant and susceptible genotypes. A total of 102 protein bands/spots were analysed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and by quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) analysis. Forty-nine non-redundant proteins were identified, implicating a variety of stress response mechanisms in peanut. Lipoxygenase and 1l-myo-inositol-1-phosphate synthase, which aid in inter- and intracellular stress signalling, were more abundant in tolerant genotypes under water-deficit stress. Acetyl-CoA carboxylase, a key enzyme of lipid biosynthesis, increased in relative abundance along with a corresponding increase in epicuticular wax content in the tolerant genotype, suggesting an additional mechanism for water conservation and stress tolerance. Additionally, there was a marked decrease in the abundance of several photosynthetic proteins in the tolerant genotype, along with a concomitant decrease in net photosynthesis in response to water-deficit stress. Differential regulation of leaf proteins involved in a variety of cellular functions (e.g. cell wall strengthening, signal transduction, energy metabolism, cellular detoxification and gene regulation) indicates that these molecules could affect the molecular mechanism of water-deficit stress tolerance in peanut. PMID:19143990

  12. Physiology Online

    NSDL National Science Digital Library

    Physiology Online, the electronic information service of the Physiological Society, provides information about its three journals: Journal of Physiology, Proceedings of the Physiological Society, and Experimental Physiology. Also included are selected abstracts, as well as information about recent monographs, job listings (mostly in the U.K.), information about Society grants, a physiology file and software archive for both PC and Mac platforms, pointers to other physiology resources on the Internet, and a listing of upcoming meetings and conferences within the field.

  13. The physiological resilience of fern sporophytes and gametophytes: advances in water relations offer new insights into an old lineage

    PubMed Central

    Pittermann, Jarmila; Brodersen, Craig; Watkins, James E.

    2013-01-01

    Ferns are some of the oldest vascular plants in existence and they are the second most diverse lineage of tracheophytes next to angiosperms. Recent efforts to understand fern success have focused on the physiological capacity and stress tolerance of both the sporophyte and the gametophyte generations. In this review, we examine these insights through the lens of plant water relations, focusing primarily on the form and function of xylem tissue in the sporophyte, as well as the tolerance to and recovery from drought and desiccation stress in both stages of the fern life cycle. The absence of secondary xylem in ferns is compensated by selection for efficient primary xylem composed of large, closely arranged tracheids with permeable pit membranes. Protection from drought-induced hydraulic failure appears to arise from a combination of pit membrane traits and the arrangement of vascular bundles. Features such as tracheid-based xylem and variously sized megaphylls are shared between ferns and more derived lineages, and offer an opportunity to compare convergent and divergent hydraulic strategies critical to the success of xylem-bearing plants. Fern gametophytes show a high degree of desiccation tolerance but new evidence shows that morphological attributes in the gametophytes may facilitate water retention, though little work has addressed the ecological significance of this variation. We conclude with an emergent hypothesis that selection acted on the physiology of both the sporophyte and gametophyte generations in a synchronous manner that is consistent with selection for drought tolerance in the epiphytic niche, and the increasingly diverse habitats of the mid to late Cenozoic. PMID:23935601

  14. Acoustical characteristics of leak signals in plastic water distribution pipes

    Microsoft Academic Search

    Osama Hunaidi; Wing T. Chu

    1999-01-01

    Acoustical characteristics of leak signals in plastic pipes were investigated in this study for several types of leaks simulated under controlled conditions at an experimental site. The investigation included the characterization of frequency content of sound or vibration signals as a function of leak type, flow rate, pipe pressure and season, the determination of the attenuation rate, and the variation

  15. Characteristics of pipe system failures in light water reactors

    Microsoft Academic Search

    S. L. Basin; E. T. Burns

    1977-01-01

    A statistical description of pipe system failures is presented. The characteristics of these failures have been derived from reports submitted by the utilities to the Nuclear Regulatory Commission. In the present study, emphasis has been placed on identifying trends in the incidence of pipe failures and on the statistical characterization of the failure events to include impact on plant availability

  16. WATER ADSORPTION AND DRYING CHARACTERISTICS OF OKRA Hibiscus Esculentus L

    Microsoft Academic Search

    FAHRETTIN GÖGUS; MEDENI MASKAN

    1999-01-01

    Moisture adsorption characteristics of okra were evaluated at 10, 20, 30° C. Isotherms were found to be of type III. Monolayer moisture contents were evaluated with GAB model. Drying was carried out at 60, 70, 80° C and drying data were analysed to obtain diffusivity values from the period of first felling drying rate. Effective diffusivity increased with increasing temperature.

  17. Controlled alternate partial root-zone irrigation: its physiological consequences and impact on water use efficiency

    Microsoft Academic Search

    Shaozhong Kang; Jianhua Zhang

    2010-01-01

    Controlled alternate partial root-zone irrigation (CAP- RI), also called partial root-zone drying (PRD) in other literature, is a new irrigation technique and may im- prove the water use efficiency of crop production without significant yield reduction. It involves part of the root system being exposed to drying soil while the remaining part is irrigated normally. The wetted and dried sides

  18. WATER STRESS ON PUNA CHICORY AND LANCELOT PLANTAIN - MORPHOLOGICAL AND PHYSIOLOGICAL EFFECTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Summer growth of cool-season species in the NE USA is reduced due to a combination of high temperature and drought. A two year experiment near State College, PA was designed to compare the effect of soil water availability conditions on chicory (Cichorium intybus L.) and plantain (Plantago lanceolat...

  19. INSTABILITY OF THE WATER DISINFECTION BY-PRODUCT DIBROMOACETONITRILE UNDER PHYSIOLOGICAL CONDITIONS: KINETICS AND PRODUCT CHARACTERIZATION

    EPA Science Inventory

    Dibromoacetonitrile (DBAN) is a prevalent haloacetonitrile formed as a byproduct of water chlorination. DBAN is toxic in vivo and genotoxic in vitro and is a mouse skin tumor initiator. However, little is known about its mechanisms of toxicity or genotoxicity or its stability. Du...

  20. Physiological studies in the South American camelid llama (Lama guanicoe f. d. glama). I. Body water spaces and water turnover.

    PubMed

    Marcilese, N A; Ghezzi, M D; Aba, M A; Alzola, R A; Solana, H; Valsecchi, R M

    1994-01-01

    Body water (BW) and extracellular water (ECW), were determined with tritiated water (THO) and 82Br injected into the vein, to 8 mature animals of both sexes during the winter season. The biological half-time of THO (T1/2 THO) and the daily water turnover (WT) were measured and the intracellular water (ICW) calculated. The studies with THO were repeated in the same animals and in 2 lactating females in spring and summer. Two calves were also studied during spring. The values obtained in winter were: BW 659 +/- 12 ml/kg; T1/2 THO 9.2 +/- 1 day; WT per 24 h 50 +/- 3 ml/kg or 116 +/- 5 ml/kg 82 and 163 +/- 9 ml per 1 of BW82; ECW 215 +/- 8 ml/kg or 32.5 +/- 3% BW; ICW 447 +/- 12 ml/kg or 67.7 +/- 4% BW. The results of the spring's studies showed a significant increase in the values of WT. In summer a further increment of this parameters was observed when expressed as ml/kg body solids. This differences were remarkable in those in lactation. The proportion of water in the body was significantly higher during summer in all animals. BW in lactating animals during summer was 783 +/- 9 ml/kg and in the other animals 718 +/- 18; T1/2 THO values were 3.3 +/- .-06 and 4.5 +/- .4 day, respectively. WT was 396 +/- 9 ml/kg.82 or 484 +/- 8 ml/l BW82 in the lactating animals and 260 +/- 9 ml/kg 82 or 341 +/- 12 ml/l BW82 in the other animals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7640403

  1. Characteristics of thermal conductivity in classical water models

    NASA Astrophysics Data System (ADS)

    Sirk, Timothy W.; Moore, Stan; Brown, Eugene F.

    2013-02-01

    The thermal conductivities of common water models are compared using equilibrium (EMD) and non-equilibrium molecular dynamics (NEMD) simulation. A complete accounting for electrostatic contributions to the heat flux was found to resolve the previously reported differing results of NEMD and EMD Green-Kubo measurements for the extended simple point-charge (SPC/E) model. Accordingly, we demonstrate the influence of long-range electrostatics on the thermal conductivity with a simple coulomb cutoff, Ewald summation, and by an extended particle-particle particle-mesh method. For each water model, the thermal conductivity is computed and decomposed in terms of frequency-dependent thermodynamic and topological contributions. The rigid, three-site SPC, SPC/E, and transferable intermolecular potential (TIP3P-Ew) water models are shown to have similar thermal conductivity values at standard conditions, whereas models that include bond stretching and angle bending have higher thermal conductivities.

  2. Survey of receiving-water environmental impacts associated with discharges from pulp mills; 1: Mill characteristics, receiving-water chemical profiles and lab toxicity tests

    SciTech Connect

    Robinson, R.D. (Univ. of Guelph, Ontario (Canada). Dept. of Environmental Biology); Carey, J.H. (National Water Research Inst., Burlington, Ontario (Canada). Rivers Research Branch); Solomon, K.R. (Centre for Toxicology, Guelph, Ontario (Canada)); Smith, I.R. (Ontario Ministry of the Environment, Toronto, Ontario (Canada). Water Resources Branch); Servos, M.R.; Munkittrick, K.R. (Department of Fisheries and Oceans, Burlington, Ontario (Canada). Great Lakes Lab. for Fisheries and Aquatic Sciences)

    1994-07-01

    This survey examined the relationship between environmental responses at pulp mill sites and the pulping process, effluent treatment, and bleaching technology used by pulp mills. This manuscript is the first in a series of four; it reviews the location and operating characteristics of mills included in the survey and provides background information on water chemistry that is relevant to the other components of the survey. In addition, lab 7-d toxicity tests of receiving water were conducted using fathead minnows (Pimephales promelas) and the cladoceran Ceriodaphnia dubia with water samples collected upstream and downstream of effluent discharges at 11 Canadian pulp and paper mills; these samples were collected at the same time as fish surveys were conducted. Survival of fathead minnow larvae was significantly reduced at four of the 11 downstream sites. Ceriodaphnia reproduction was significantly higher at six of the 11 downstream sites and significantly lower at two downstream sites. There were no significant effects on fathead minnow larva growth or adult Ceriodaphnia survival at any of the examined downstream sites. Negative effects in the toxicity tests were generally associated with the low dilution discharge of primary treated effluent with a previous history of acute toxicity. Fathead minnow and Ceriodaphnia tests were generally correlated with historical data on benthic macroinvertebrate community responses. Neither toxicity test predicted the physiological changes in wild fish that are presented in accompanying papers.

  3. Characteristics of hydrogen bond revealed from water clusters

    NASA Astrophysics Data System (ADS)

    Song, Yan; Chen, Hongshan; Zhang, Cairong; Zhang, Yan; Yin, Yuehong

    2014-09-01

    The hydrogen bond network is responsible for the exceptional physical and chemical properties of water, however, the description of hydrogen bond remains a challenge for the studies of condensed water. The investigation of structural and binding properties of water clusters provides a key for understanding the H-bonds in bulk water. In this paper, a new set of geometric parameters are defined to describe the extent of the overlap between the bonding orbital of the donor OH and the nonbonding orbital of the lone-pair of the acceptor molecule. This orbital overlap plays a dominant role for the strength of H-bonds. The dependences of the binding energy of the water dimer on these parameters are studied. The results show that these parameters properly describe the H-bond strength. The ring, book, cage and prism isomers of water hexamer form 6, 7, 8 and 9 H-bonds, and the strength of the bonding in these isomers changes markedly. The internally-solvated and the all-surface structures of (H2O) n for n = 17, 19 and 21 are nearly isoenergetic. The internally-solvated isomers form fewer but stronger H-bonds. The hydrogen bonding in the above clusters are investigated in detail. The geometric parameters can well describe the characters of the H-bonds, and they correlate well with the H-bond strength. For the structures forming stronger H-bonds, the H-bond lengths are shorter, the angle parameters are closer to the optimum values, and their rms deviations are smaller. The H-bonds emanating from DDAA and DDA molecules as H-donor are relatively weak. The vibrational spectra of (H2O) n ( n = 17, 19 and 21) are studied as well. The stretching vibration of the intramolecular OH bond is sensitive to its bonding environment. The H-bond strength judged from the geometric parameters is in good agreement with the bonding strength judged from the stretching frequencies.

  4. Morphological and physiological characteristics of Gephyrocapsa oceanica var. typica Kamptner 1943 in culture experiments: evidence for genotypic variability.

    PubMed

    Bollmann, Jörg; Klaas, Christine; Brand, Larry E

    2010-01-01

    In order to test whether morphological variations within Gephyrocapsa oceanica var. typica Kamptner 1943 reflect genotypic variation or phenotypic responses to environmental conditions, culture experiments of six strains of G. oceanica collected at different locations in the North Atlantic and Mediterranean have been carried out under different temperature and nutrients conditions. All morphological, and physiological data suggest the presence of two species or subspecies within G. oceanica var typica that correspond morphologically to Gephyrocapsa "Larger" and possibly to Gephyrocapsa "Equatorial" as previously defined from Holocene sediments. Given the importance of Gephyrocapsa species for the carbon cycle in the past, genetic studies on this group are of major interest to the understanding of past climate change and plankton evolution. PMID:19836304

  5. Comparison of DXA and water measurements of body fat following gastric bypass surgery and a physiological model of body water, fat, and muscle composition.

    PubMed

    Levitt, David G; Beckman, Lauren M; Mager, Jennifer R; Valentine, Bret; Sibley, Shalamar D; Beckman, Tiffany R; Kellogg, Todd A; Ikramuddin, Sayeed; Earthman, Carrie P

    2010-09-01

    Measurement of body composition changes following bariatric surgery is complicated because of the difficulty of measuring body fat in highly obese individuals that have increased photon absorption and are too large for the standard dual-energy X-ray absorptiometry (DXA) table. We reproducibly measured body composition from half-body DXA scans and compared the values of total body fat estimated from total body water (TBW) and DXA measurements before and after Roux-en-Y gastric bypass surgery (RYGB). DXA, TBW (deuterium dilution), extracellular water (ECW; bromide dilution), and intracellular water (ICW) measurement (by subtraction) were made before surgery and at 2 wk, 6 wk, 6 mo, and 12 mo after surgery. Twenty individuals completed baseline and at least four follow-up visits. DXA appeared to underestimate the fat and bone mass in extreme obesity (before surgery), whereas at 6 and 12 mo after surgery, the DXA and TBW fat measurements were similar. The ECW-to-ICW ratio was increased in obese individuals and increased slightly more after surgery. We describe a new model that explains this abnormal water composition in terms of the normal physiological changes that occur in body composition in obesity and weight loss. This model is also used to predict the muscle mass loss following RYGB. PMID:20558754

  6. Infiltration characteristics of bare soil under sequential water application events

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The marked reduction in infiltration rate caused by formation of a soil surface seal is a well known phenomenon but often ignored in infiltration models. The effect sequential water application events have on infiltration rate and soil surface seal formation has rarely been investigated. The objecti...

  7. Physiological Effects of Saline Water on Two Economically Important Horticultural Crops in South Texas 

    E-print Network

    Simpson, Catherine Ross

    2013-12-02

    ). Glycophytic crops, which include most agricultural crop species, are negatively impacted by salt stress which results in yield and sometimes quality decreases (Bernstein, 1975; Maas, 1992). Important agronomic crops such as citrus and watermelons... evaporative cooling, if plants do not have enough water, stomata remain closed which leads to carbon starvation eventually resulting in leaf/tree death (Bañuls et al., 1997; Lloyd et al., 1990; Maas, 1992). To meet citrus transpirational demands many...

  8. Physiological parameters of plants as indicators of water quality in a constructed wetland

    Microsoft Academic Search

    Oren Shelef; Avi Golan-Goldhirsh; Tanya Gendler; Shimon Rachmilevitch

    Introduction  Increasing demand for water has stimulated efforts to treat wastewater for reuse in agriculture. Decentralized facilities\\u000a for wastewater treatment became popular as a solution to remote and small communities. These systems mimic natural wetlands,\\u000a cleaning wastewater as they flow through a complex of filter media, microbial fauna, and vegetation. The function of plants\\u000a in constructed wetlands (CWs) has not been

  9. The fate of glyphosate in water hyacinth and its physiological and biochemical influences on growth of algae

    SciTech Connect

    Tsai, Baolong.

    1989-01-01

    Absorption, translocation, distribution, exudation, and guttation of {sup 14}C-glyphosate in water hyacinth (Eichhornia crassipes) were studied. Glyphosphate entered the plant by foliage and solution treatment. Plants were harvested and separated into the following parts: treated leaf blade, treated leaf petiole, young leaf blade, young leaf petiole, old leak blade, old leaf petiole, and root. Each part was extracted with methanol. Treated leaves, which exist only in foliage treatment, were washed with water and chloroform to remove the glyphosate residues. All {sup 14}C counting was made by liquid scintillation spectrometry. Autoradiography was used to locate {sup 14}C-glyphosate after foliage treatment. Results indicated that glyphosate can be absorbed from the leaf surface and translocated rapidly through phloem tissues into the whole plant body. The roots of water hyacinth absorbed glyphosate without vertical transport. Guttation of glyphosate occurred in treated leaf tips. Exudation of glyphosate from roots of water hyacinth occurred within 8 hr after foliage treatment. Chlorella vulgaris, Chlamydomonas reihardii, Anabaena cylindrica, and Chroococcus turgidus were used to explore the physiological and biochemical effects of glyphosate on algae. Spectrophotometric assays were performed for algal growth, chlorophyll, carotenoids, phycobiliprotein, carbohydrate, and protein. TLC procedures and an image analyzer were used to detect the metabolites of glyphosate inside algal cells. The common visible symptom of glyphosate toxicity in all algal cells were bleaching effect and reduction of contents of carbohydrate, protein, and pigments. The results highly suggested that glyphosate injured the algal cells by destruction of photosynthetic pigments and resulted in lowering the contents of carbohydrate and protein in algal cells.

  10. Developing joint probability distributions of soil water retention characteristics

    Microsoft Academic Search

    Robert F. Carsel; Rudolph S. Parrish

    1988-01-01

    A method is presented for developing probability density functions for parameters of soil moisture relationships of capillary head (h(Phi)) and hydraulic conductivity (K(Phi)). These soil moisture parameters are required for the assessment of water flow and solute transport in unsaturated media. The method employs a statistical multiple regression equations proposed in the literature for estimating (h(Phi)) or (K(Phi)) relationships using

  11. Hydrogeochemical characteristics of some Cameroon bottled waters, investigated by multivariate statistical analyses

    Microsoft Academic Search

    Stephanie Abonoje Oyebog; Andrew Ako Ako; George Elambo Nkeng; Emmanuel Cheo Suh

    In this study, 8 bottled water brands sold in Cameroon were analyzed for 76 elements\\/parameters by ICP-MS, IC, titration and mass spectrometric methods. This was to investigate the geochemical characteristics of the bottled waters in order to identify the main hydro geochemical processes controlling their chemical content. A comparison of the element concentrations and the legal limits for both bottled

  12. Calculation study of water injection on compressor characteristics of a GT009 gas-turbine installation

    Microsoft Academic Search

    Yu. M. Anurov; A. Yu. Peganov; A. V. Skvortsov; A. L. Berkovich; V. G. Polishchuk

    2006-01-01

    Results of a calculation study of motion and evaporation of water in the compressor flow path of a GT-009 gas-turbine installation\\u000a are presented. The effects of water injection on the main characteristics of the compressor operation are analyzed.

  13. Water Accessibilities of Man-made Cellulosic Fibers – Effects of Fiber Characteristics

    Microsoft Academic Search

    Satoko Okubayashi; Ulrich J. Griesser; Thomas Bechtold

    2005-01-01

    The dynamic vapor water sorption and desorption experiments were performed on cellulosic fibers with different characteristics. The hysteresis between moisture sorption and desorption cycle at 10% relative humidity (RH) was independent on the total moisture regain and approximately 45% for all materials except for viscose fibers. Brunauer–Emmett–Teller surface volume (Vm) for moisture sorption and retention capacity of liquid water (WRV)

  14. The Influence Of Water Tracks And Hillslope Position On The Physiology Of The Dominant Plant Species In The Imnavait Creek Watershed, Alaska

    Microsoft Academic Search

    K. L. Griffin; D. J. Epstein; J. B. Shapiro; N. T. Boelman; M. Stieglitz

    2003-01-01

    Within a small arctic tundra watershed located on the north slope of Alaska, we asked if plant abundance and physiological performance are linked to hillslope position by the hydrologic processes controlling nutrient availability. Our prediction was that down slope sites and within water track sites should have the greatest nutrient availability resulting in the highest photosynthetic capacity and productivity. To

  15. Spatial Patterns of HWA Damage and Impacts on Tree Physiology and Water Use in the Black Rock Forest, Southern New York

    Microsoft Academic Search

    Aaron Kimple; William Schuster

    This study was designed to document spatial patterns in HWA damage in three hemlock stands in the Black Rock Forest, southeastern New York, 4 to 8 years after adelgid infestation, and to quantify HWA impact on hemlock operating physiology and water use. In all three stands, damage was more severe along the stream courses and less severe away from the

  16. [Temporomandibular fibro-chondromalacia. Physiological basis. Classification on the basis of clinical characteristics and course. Spongialisation (author's transl)].

    PubMed

    Couly, G; Dautrey, J

    1982-01-01

    The temporomandibular joints are neural structures which develop from the cephalic ectomesenchyme of the neural crests. They are analogous to the effector organs. Their lesional abnormalities have two characteristics:--pain sensation,--"foreign body". A classification is suggested on the basis of clinical characteristics and course of articular signs due to temporo-menisco-condylar stress resulting from occlusion problems, and concomitant lesions of the articular fibrocartilage: closed and open fibro-chondromalacia. Emphasis is placed upon the constant dissociation between articular clinical features and nosography. Spongialisation, or the property of regeneration of fibrocartilage from spongy bone tissue fully justifies the technique of condyloplasty to remodel the temporomandibular joints in the presence of fibro-chondromalacia. The future lies in the distinction between fibro-chondromalacia secondary to occlusive stress and that due to primary ischaemia of bone. PMID:6954631

  17. Toxic Effects of Ethyl Cinnamate on the Photosynthesis and Physiological Characteristics of Chlorella vulgaris Based on Chlorophyll Fluorescence and Flow Cytometry Analysis

    PubMed Central

    Jiao, Yang; Ouyang, Hui-Ling; Jiang, Yu-Jiao; Kong, Xiang-Zhen; He, Wei; Liu, Wen-Xiu; Yang, Bin; Xu, Fu-Liu

    2015-01-01

    The toxic effects of ethyl cinnamate on the photosynthetic and physiological characteristics of Chlorella vulgaris were studied based on chlorophyll fluorescence and flow cytometry analysis. Parameters, including biomass, Fv/Fm (maximal photochemical efficiency of PSII), ?PSII (actual photochemical efficiency of PSII in the light), FDA, and PI staining fluorescence, were measured. The results showed the following: (1) The inhibition on biomass increased as the exposure concentration increased. 1?mg/L ethyl cinnamate was sufficient to reduce the total biomass of C. vulgaris. The 48-h and 72-h EC50 values were 2.07?mg/L (1.94–2.20) and 1.89?mg/L (1.82–1.97). (2) After 24?h of exposure to 2–4?mg/L ethyl cinnamate, the photosynthesis of C. vulgaris almost ceased, manifesting in ?PSII being close to zero. After 72?h of exposure to 4?mg/L ethyl cinnamate, the Fv/Fm of C. vulgaris dropped to zero. (3) Ethyl cinnamate also affected the cellular physiology of C. vulgaris, but these effects resulted in the inhibition of cell yield rather than cell death. Exposure to ethyl cinnamate resulted in decreased esterase activities in C. vulgaris, increased average cell size, and altered intensities of chlorophyll a fluorescence. Overall, esterase activity was the most sensitive variable.

  18. Differential Gene Expression Reflects Morphological Characteristics and Physiological Processes in Rice Immunity against Blast Pathogen Magnaporthe oryzae

    PubMed Central

    Mahmood, Maziah; Abdullah, Siti N. A.; Hanafi, Mohamed M.; Nejat, Naghmeh; Latif, Muhammad A.

    2015-01-01

    The rice blast fungus Magnaporthe oryzae is a serious pathogen that jeopardises the world’s most important food-security crop. Ten common Malaysian rice varieties were examined for their morphological, physiological and genomic responses to this rice blast pathogen. qPCR quantification was used to assess the growth of the pathogen population in resistant and susceptible rice varieties. The chlorophyll content and photosynthesis were also measured to further understand the disruptive effects that M. oryzae has on infected plants of these varieties. Real-time PCR was used to explore the differential expression of eight blast resistance genes among the ten local varieties. Blast disease has destructive effects on the growth of rice, and the findings of our study provide evidence that the Pikh, Pi9, Pi21, and Osw45 genes are involved in defence responses in the leaves of Malaysian rice at 31 h after inoculation with M. oryzae pathotype P7.2. Both the chlorophyll content and photosynthesis were reduced, but the levels of Pikh gene expression remained constant in susceptible varieties, with a developed pathogen population and mild or severe symptoms. The Pi9, Pi21, and Osw45 genes, however, were simultaneously upregulated in infected rice plants. Therefore, the presence of the Pikh, Pi9, Pi21, and Osw45 genes in the germplasm is useful for improving the resistance of rice varieties. PMID:26001124

  19. Differential Gene Expression Reflects Morphological Characteristics and Physiological Processes in Rice Immunity against Blast Pathogen Magnaporthe oryzae.

    PubMed

    Azizi, Parisa; Rafii, Mohd Y; Mahmood, Maziah; Abdullah, Siti N A; Hanafi, Mohamed M; Nejat, Naghmeh; Latif, Muhammad A; Sahebi, Mahbod

    2015-01-01

    The rice blast fungus Magnaporthe oryzae is a serious pathogen that jeopardises the world's most important food-security crop. Ten common Malaysian rice varieties were examined for their morphological, physiological and genomic responses to this rice blast pathogen. qPCR quantification was used to assess the growth of the pathogen population in resistant and susceptible rice varieties. The chlorophyll content and photosynthesis were also measured to further understand the disruptive effects that M. oryzae has on infected plants of these varieties. Real-time PCR was used to explore the differential expression of eight blast resistance genes among the ten local varieties. Blast disease has destructive effects on the growth of rice, and the findings of our study provide evidence that the Pikh, Pi9, Pi21, and Osw45 genes are involved in defence responses in the leaves of Malaysian rice at 31 h after inoculation with M. oryzae pathotype P7.2. Both the chlorophyll content and photosynthesis were reduced, but the levels of Pikh gene expression remained constant in susceptible varieties, with a developed pathogen population and mild or severe symptoms. The Pi9, Pi21, and Osw45 genes, however, were simultaneously upregulated in infected rice plants. Therefore, the presence of the Pikh, Pi9, Pi21, and Osw45 genes in the germplasm is useful for improving the resistance of rice varieties. PMID:26001124

  20. Development of study on the dynamic characteristics of deep water mooring system

    Microsoft Academic Search

    You-Gang Tang; Su-Xia Zhang; Ruo-Yu Zhang; Hai-Xiao Liu

    2007-01-01

    To meet the needs of those exploiting deepwater resources, TLP and SPAR platforms are used in some areas and are considered\\u000a excellent platforms in deep water. However, many problems remain to be resolved. The design of mooring systems is a key issue\\u000a for deep water platforms. Environmental loads in deep water effect the physical characteristics of mooring line materials.\\u000a The

  1. Anatomy & Physiology

    MedlinePLUS

    Search SEER Training: SEER Training Modules Print Home Glossary Citation Help Home » Cancer Registration & Surveillance Modules » Anatomy & Physiology Cancer Registration & Surveillance Modules Anatomy & Physiology Intro ...

  2. Agrichemicals in ground water of the midwestern USA: Relations to soil characteristics

    USGS Publications Warehouse

    Burkart, M.R.; Kolpin, D.W.; Jaquis, R.J.; Cole, K.J.

    1999-01-01

    A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to ground water. This paper examines the relation of local soil characteristics to concentrations and occurrence of nitrate, atrazine (2-chloro-4 ethylamino-6-isopropylamino- s-trazine), and atrazine residue [atrazine + deethylatrazine (2-amino-4- chloro-6-isopropylamino-s-triazine) + deisopropylatrazine (2-amino-4-chloro- 6-ethylamino-s-triazine)] from 99 wells completed in unconsolidated aquifers across the midwestern USA. The occurrence and concentrations of nitrate and atrazine in ground water were directly related to soil characteristics that determine the rate of water movement. The substantial differences in the relations found among soil characteristics and nitrate and atrazine in ground water suggest that different processes affect the transformation, adsorption, and transport of these contaminants. A multivariate analysis determined that the soil characteristics examined explained the amount of variability in concentrations for nitrate (19.0%), atrazine (33.4%), and atrazine residue (28.6%). These results document that, although soils do affect the transport of agrichemicals to ground water, other factors such as hydrology, land use, and climate must also be considered to understand the occurrence of agrichemicals in ground water.

  3. Effects of Plant-Growth-Promoting Rhizobacteria on Yield, Growth, and Some Physiological Characteristics of Wheat and Barley Plants

    Microsoft Academic Search

    Metin Turan; Medine Gulluce; Fikrettin ?ahin

    2012-01-01

    In 2009 a greenhouse experiment was conducted to determine the effects of boron (B) and plant growth-promoting rhizobacteria (PGPR) treatments, applied either alone or in combination, on yield, plant growth, leaf total chlorophyll content, stomatal conductance, membrane leakage, and leaf relative water content of wheat (Triticum aestivum L. cv. Bezostiya) and barley (Hordeum vulgare L. cv. Tokak) plants. Results showed

  4. A Comparison of Water Balance Components of a Spruce and a Beech Canopy Based on Parallel Micrometeorological and Plant Physiological Measurements

    Microsoft Academic Search

    Uwe Spank; Christian Bernhofer; Falko Clausnitzer; Babara Köstner; Kai Schwärzel; Karl-Heinz Feger

    2010-01-01

    We present the investigations of water balances of two neighbouring canopies, a spruce and a beech canopy. The water balances were analyzed on small scale of areas less than 0.5 km2 during two growing seasons. The investigations are based on a combination of different meteorological (eddy-covariance measurements, EC) and plant physiological measurements (sap flow measurements, SF), as well as on

  5. Physiological Indicators of Plant Water Status of Irrigated and Non-irrigated Grapevines Grown in a Low Rainfall Area of Portugal

    Microsoft Academic Search

    T. A. Sousa; M. T. Oliveira; J. M. Pereira

    2006-01-01

    Water is a key resource in commercial wine production and both large excesses and deficits have undesirable effects upon the\\u000a amount and quality of the wine produced. A balance between the water requirements of a fully developed canopy and the induced\\u000a stress necessary for the commercial quality of the wine must be reached. Thus we need a physiological indicator that

  6. Understanding how the leaf physiology of mangrove plants differs from fresh water plants: a fundamental step to use cellulose as a proxy for sea level rise

    Microsoft Academic Search

    P. Ellsworth; L. O. Sternberg

    2010-01-01

    We studied the leaf water isotopic enrichment pattern of mangrove (halophytes) and hammock (glycophytes) plants as an attempt to explain why the delta18O of stem cellulose from mangrove and hammock species have no relationship with the delta18O of source water. A better understanding of leaf physiology of mangroves and its effect on the delta18O of stem cellulose is the first

  7. Dipole receiver characteristics in the presence of sea water

    NASA Technical Reports Server (NTRS)

    Kao, P. S.

    1972-01-01

    The receive properties for a dipole in the presence of sea water were obtained by solving integral equations for currents along the unloaded dipole and its image. For dipoles of 0.1 wavelength or higher above the sea surface, the performance resembled that of a dipole over a perfectly conducting plane; for dipoles within 0.1 wavelength above the sea surface, the relative gain dropped in about the same proportion as the relative reduction in the strength of the resultant electric field. An insulated wavelength/2 dipole with a conjugate load matched in free space had a relative power gain of 17 db below isotropic at the sea surface.

  8. Effect of Saline Water Irrigation on Growth and Physiological Responses of Three Rose Rootstocks

    PubMed Central

    Niu, Genhua; Rodriguez, Denise S.; Aguiniga, Lissie

    2009-01-01

    Salt-tolerant landscape plants are needed for arid and semiarid regions where the supply of quality water is limited and soil salinization often occurs. This study evaluated growth, chloride (Cl) and sodium (Na) uptake, relative chlorophyll content, and chlorophyll fluorescence of three rose rootstocks [Rosa ×fortuniana Lindl., R. multiflora Thunb., and R. odorata (Andr.) Sweet] irrigated with saline solutions at 1.6 (control), 3.0, 6.0, or 9.0 dS·m ?1 electrical conductivity in a greenhouse. After 15 weeks, most plants in 9.0 dS·m ?1 treatment died regardless of rootstock. Significant growth reduction was observed in all rootstocks at 6.0 dS·m ?1 compared with the control and 3.0 dS·m ?1, but the reduction in R. ×fortuniana was smaller than in the other two rootstocks. The visual scores of R. multiflora at 3.0 and 6.0 dS·m?1 were slightly lower than those of the other rootstocks. Rosa odorata had the highest shoot Na concentration followed by R. multiflora; however, R. multiflora had the highest root Na concentration followed by R. odorata. All rootstocks had higher Cl accumulation in all plant parts at elevated salinities, and no substantial differences in Cl concentrations in all plant parts existed among the rootstocks, except for leaf Cl concentration in R. multiflora, which was higher than those in the other two rootstocks. The elevated salinities of irrigation water reduced the relative chlorophyll concentration, measured as leaf SPAD readings, and maximal photochemical efficiency of photosystem II (PSII) and minimal fluorescence (F0)/maximum fluorescence (Fv/Fm), but the largest reduction in Fv/Fm was only 2.4%. Based on growth and visual quality, R. ×fortuniana was relatively more salt-tolerant than the other two rootstocks and R. odorata was slightly more salt-tolerant than R. multiflora. PMID:20148186

  9. Carbon and water flux responses to physiology by environment interactions: a sensitivity analysis of variation in climate on photosynthetic and stomatal parameters

    NASA Astrophysics Data System (ADS)

    Bauerle, William L.; Daniels, Alex B.; Barnard, David M.

    2014-05-01

    Sensitivity of carbon uptake and water use estimates to changes in physiology was determined with a coupled photosynthesis and stomatal conductance ( g s) model, linked to canopy microclimate with a spatially explicit scheme (MAESTRA). The sensitivity analyses were conducted over the range of intraspecific physiology parameter variation observed for Acer rubrum L. and temperate hardwood C3 (C3) vegetation across the following climate conditions: carbon dioxide concentration 200-700 ppm, photosynthetically active radiation 50-2,000 ?mol m-2 s-1, air temperature 5-40 °C, relative humidity 5-95 %, and wind speed at the top of the canopy 1-10 m s-1. Five key physiological inputs [quantum yield of electron transport ( ?), minimum stomatal conductance ( g 0), stomatal sensitivity to the marginal water cost of carbon gain ( g 1), maximum rate of electron transport ( J max), and maximum carboxylation rate of Rubisco ( V cmax)] changed carbon and water flux estimates ?15 % in response to climate gradients; variation in ?, J max, and V cmax input resulted in up to ~50 and 82 % intraspecific and C3 photosynthesis estimate output differences respectively. Transpiration estimates were affected up to ~46 and 147 % by differences in intraspecific and C3 g 1 and g 0 values—two parameters previously overlooked in modeling land-atmosphere carbon and water exchange. We show that a variable environment, within a canopy or along a climate gradient, changes the spatial parameter effects of g 0, g 1, ?, J max, and V cmax in photosynthesis- g s models. Since variation in physiology parameter input effects are dependent on climate, this approach can be used to assess the geographical importance of key physiology model inputs when estimating large scale carbon and water exchange.

  10. Insect Physiology Online

    NSDL National Science Digital Library

    0000-00-00

    A large database dedicated to research articles about various topics of insect physiology. Topics range from excretion to diapause to temperature and water regulation. There are also extensive listings of resources (academic units, funding, journals) and course data on insect physiology.

  11. Characteristics of Water Vapor Under Partially Cloudy Conditions: Observations by the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Fishbein, E.

    2003-12-01

    The variability and quality of tropical water vapor derived from the Atmospheric Infrared Sounder (AIRS) are characterized. Profiles of water vapor, temperature and surface characteristics (states) are derived from coincident Advance Microwave Sounding Unit (AMSU) and 3x3 sets of AIRS footprints. States are obtained under partially cloudy conditions by estimating the radiances emitted from the clear portions of the AIRS footprints. This procedure, referred to as cloud clearing, amplifies the measurement noise, and the amplification increases with cloud amount and uniformity. Cumulus and stratus cloud amount are related to the water vapor saturation, and noise amplification and water vapor amount may be partially correlated. The correlations between the uncertainty of retrieved water vapor, cloudiness and noise amplification are characterized. Retrieved water vapor is generally good when the amplification is less than three. Water vapor profiles are compared with correlative data, such as radiosondes and numerical weather center analyses and are in relatively good agreement in the lower troposphere

  12. A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus.

    PubMed

    Greenwood, Michael P; Mecawi, Andre S; Hoe, See Ziau; Mustafa, Mohd Rais; Johnson, Kory R; Al-Mahmoud, Ghada A; Elias, Lucila L K; Paton, Julian F R; Antunes-Rodrigues, Jose; Gainer, Harold; Murphy, David; Hindmarch, Charles C T

    2015-04-01

    Salt loading (SL) and water deprivation (WD) are experimental challenges that are often used to study the osmotic circuitry of the brain. Central to this circuit is the supraoptic nucleus (SON) of the hypothalamus, which is responsible for the biosynthesis of the hormones, arginine vasopressin (AVP) and oxytocin (OXT), and their transport to terminals that reside in the posterior lobe of the pituitary. On osmotic challenge evoked by a change in blood volume or osmolality, the SON undergoes a function-related plasticity that creates an environment that allows for an appropriate hormone response. Here, we have described the impact of SL and WD compared with euhydrated (EU) controls in terms of drinking and eating behavior, body weight, and recorded physiological data including circulating hormone data and plasma and urine osmolality. We have also used microarrays to profile the transcriptome of the SON following SL and remined data from the SON that describes the transcriptome response to WD. From a list of 2,783 commonly regulated transcripts, we selected 20 genes for validation by qPCR. All of the 9 genes that have already been described as expressed or regulated in the SON by osmotic stimuli were confirmed in our models. Of the 11 novel genes, 5 were successfully validated while 6 were false discoveries. PMID:25632023

  13. Effect of ammonium and nitrate nutrition on some physiological processes in higher plants - growth, photosynthesis, photorespiration, and water relations.

    PubMed

    Guo, S; Zhou, Y; Shen, Q; Zhang, F

    2007-01-01

    Ammonium and nitrate as different forms of nitrogen nutrients impact differently on some physiological and biochemical processes in higher plants. Compared to nitrate, ammonium results in small root and small leaf area, which may contribute to a low carbon gain, and an inhibition on growth. On the other hand, due to (photo)energy saving, a higher CO (2) assimilation rate per leaf area was observed frequently in plants supplied with ammonium than in those supplied with nitrate. These results were dependent not only on higher Rubisco content and/or activity, but also on RuBP regeneration rate. The difference in morphology such as chloroplast volume and specific leaf weight might be the reason why the CO (2) concentration in the carboxylation site and hence the photorespiration rate differs in plants supplied with the two nitrogen forms. The effect of nitrogen form on water uptake and transportation in plants is dependent both on leaf area or shoot parameter, and on the root activity (i.e., root hydraulic conductivity, aquaporin activity). PMID:17048140

  14. Statistical Analysis of Drinking Water Treatment Plant Costs, Source Water Quality, and Land Cover Characteristics

    Microsoft Academic Search

    Jade Freeman; Rebecca Madsen; Kelley Hart; Paul Barten; Paul Gregory; David Reckhow; Woody Duncan

    Revisiting an earlier study conducted by The Trust for Public Land in 2004, this research brings new data and methodologies to offer insight on the impact of the decline of forest cover and the increase of agriculture or urban land cover in a drinking water source drainage area on the water quality for that drinking water source and the drinking

  15. Water clarity, maternal behavior, and physiology combine to eliminate UV radiation risk to amphibians in a montane landscape

    PubMed Central

    Palen, Wendy J.; Schindler, Daniel E.

    2010-01-01

    Increasing UV-B radiation (UV-B; 290–320 nm) due to stratospheric ozone depletion has been a leading explanation for the decline in amphibians for nearly 2 decades. Yet, the likelihood that UV-B can influence amphibians at the large spatial scales relevant to population declines has not yet been evaluated. A key limitation has been in relating results from individual sites to the effect of UV-B for populations distributed across heterogeneous landscapes. We measured critical embryonic exposures to UV-B for two species of montane amphibians with contrasting physiological sensitivities, long-toed salamander (Ambystoma macrodactylum) and Cascades frog (Rana cascadae), at field sites spanning a gradient of UV-B attenuation in water. We then used these experimental results to estimate the proportion of embryos exposed to harmful UV-B across a large number of breeding sites. By combining surveys of the incubation timing, incident UV-B, optical transparency of water, and oviposition depth and light exposure of embryos at each site, we present a comprehensive assessment of the risk posed by UV-B for montane amphibians of the Pacific Northwest. We found that only 1.1% of A. macrodactylum and no R. cascadae embryos across a landscape of breeding sites are exposed to UV-B exceeding lethal levels. These results emphasize that accurately estimating the risk posed by environmental stressors requires placing experimental results in a broader ecological context that accounts for the heterogeneity experienced by populations distributed across natural landscapes. PMID:20479221

  16. Water clarity, maternal behavior, and physiology combine to eliminate UV radiation risk to amphibians in a montane landscape.

    PubMed

    Palen, Wendy J; Schindler, Daniel E

    2010-05-25

    Increasing UV-B radiation (UV-B; 290-320 nm) due to stratospheric ozone depletion has been a leading explanation for the decline in amphibians for nearly 2 decades. Yet, the likelihood that UV-B can influence amphibians at the large spatial scales relevant to population declines has not yet been evaluated. A key limitation has been in relating results from individual sites to the effect of UV-B for populations distributed across heterogeneous landscapes. We measured critical embryonic exposures to UV-B for two species of montane amphibians with contrasting physiological sensitivities, long-toed salamander (Ambystoma macrodactylum) and Cascades frog (Rana cascadae), at field sites spanning a gradient of UV-B attenuation in water. We then used these experimental results to estimate the proportion of embryos exposed to harmful UV-B across a large number of breeding sites. By combining surveys of the incubation timing, incident UV-B, optical transparency of water, and oviposition depth and light exposure of embryos at each site, we present a comprehensive assessment of the risk posed by UV-B for montane amphibians of the Pacific Northwest. We found that only 1.1% of A. macrodactylum and no R. cascadae embryos across a landscape of breeding sites are exposed to UV-B exceeding lethal levels. These results emphasize that accurately estimating the risk posed by environmental stressors requires placing experimental results in a broader ecological context that accounts for the heterogeneity experienced by populations distributed across natural landscapes. PMID:20479221

  17. Gas exchange characteristics, metabolic rate and water loss of the Heelwalker, Karoophasma biedouwensis (Mantophasmatodea: Austrophasmatidae).

    PubMed

    Chown, S L; Marais, E; Picker, M D; Terblanche, J S

    2006-05-01

    This study presents the first physiological information for a member of the wingless Mantophasmatodea, or Heelwalkers. This species shows cyclic gas exchange with no evidence of a Flutter period (more typical of discontinuous gas exchange in insects) and no indication that the spiracles are fully occluded during quiescent metabolism. Standard metabolic rate at 20 degrees C was 21.32+/-2.73 microl CO(2)h(-1) (mean+/-S.E.), with a Q(10) (10-25 degrees C) of 1.7. Increases in V()CO(2) associated with variation in mass and with trial temperature were modulated by an increase in burst period volume and a decline in cycle frequency. Total water loss rate, determined by infrared gas analysis, was 0.876+/-0.08 mg H(2)Oh(-1) (range 0.602-1.577, n=11) whilst cuticular water loss rate, estimated by linear regression of total water loss rate and metabolic rate, was 0.618+/-0.09 mg H(2)Oh(-1) (range 0.341-1.363, n=11). Respiratory water loss rate was therefore no more than 29% of the total rate of water loss. Both total water loss rate and estimated cuticular water loss rate were significantly repeatable, with intraclass correlation coefficients of 0.745 and 0.553, respectively. PMID:16466738

  18. Morphological and physicochemical characteristics of iron corrosion scales formed under different water source histories in a drinking water distribution system.

    PubMed

    Yang, Fan; Shi, Baoyou; Gu, Junnong; Wang, Dongsheng; Yang, Min

    2012-10-15

    The corrosion scales on iron pipes could have great impact on the water quality in drinking water distribution systems (DWDS). Unstable and less protective corrosion scale is one of the main factors causing "discolored water" issues when quality of water entering into distribution system changed significantly. The morphological and physicochemical characteristics of corrosion scales formed under different source water histories in duration of about two decades were systematically investigated in this work. Thick corrosion scales or densely distributed corrosion tubercles were mostly found in pipes transporting surface water, but thin corrosion scales and hollow tubercles were mostly discovered in pipes transporting groundwater. Magnetite and goethite were main constituents of iron corrosion products, but the mass ratio of magnetite/goethite (M/G) was significantly different depending on the corrosion scale structure and water source conditions. Thick corrosion scales and hard shell of tubercles had much higher M/G ratio (>1.0), while the thin corrosion scales had no magnetite detected or with much lower M/G ratio. The M/G ratio could be used to identify the characteristics and evaluate the performances of corrosion scales formed under different water conditions. Compared with the pipes transporting ground water, the pipes transporting surface water were more seriously corroded and could be in a relatively more active corrosion status all the time, which was implicated by relatively higher siderite, green rust and total iron contents in their corrosion scales. Higher content of unstable ferric components such as ?-FeOOH, ?-FeOOH and amorphous iron oxide existed in corrosion scales of pipes receiving groundwater which was less corroded. Corrosion scales on groundwater pipes with low magnetite content had higher surface area and thus possibly higher sorption capacity. The primary trace inorganic elements in corrosion products were Br and heavy metals. Corrosion products obtained from pipes transporting groundwater had higher levels of Br, Ti, Ba, Cu, Sr, V, Cr, La, Pb and As. PMID:22882957

  19. Bio-optical characteristics of Cariaco Basin (Caribbean Sea) waters

    NASA Astrophysics Data System (ADS)

    Lorenzoni, Laura; Hu, Chuanmin; Varela, Ramón; Arias, Glenda; Guzmán, Laurencia; Muller-Karger, Frank

    2011-04-01

    Bio-optical properties of marine waters of the Cariaco Basin (southeastern Caribbean Sea) were assessed monthly between 1995 and 2005 as part of the CARIACO Ocean Time Series program. Temporal changes in light quality and penetration were caused by seasonal variation in the concentration of three major optical constituents, namely phytoplankton, detrital particles, and colored dissolved organic matter (CDOM). All constituents showed higher absorption coefficients during the upwelling season (January-May) compared to the rainy season (June-November). Both the absorption coefficient due to CDOM ( ag(440)) and due to phytoplankton ( aph(440)) had similar contributions to total absorption of light during the upwelling season ( aph(440)=0.062±0.042 m -1, ag(440)=0.065±0.047 m -1). In contrast, ag(440) dominated light absorption during the rainy season ( aph(440)=0.017±0.011 m -1, ag(440)=0.057±0.031). This led to an overestimate in SeaWiFS-derived chlorophyll concentrations during the rainy season, of between 7% and 45%. The detrital component, ad(440), typically showed the smallest contribution ( ad(440)=0.021±0.014 m -1 during upwelling and 0.007±0.001 m -1 during the rainy season). There was no clear relationship between the various optically active components in time. During the upwelling season the chlorophyll-specific absorption coefficient, aph*(440), was nearly half the value observed during the rainy season due to changes in the package effect (explaining ˜40% of the variability) and in accessory pigment composition as a result of species succession (explaining ˜60% of the variability). The euphotic zone depth (depth of the 1% photosynthetic active radiation (PAR) level) was typically shallower during the upwelling season (36.7±12.3 m) than during the rainy season (47.9±13.5 m) due to the onset of a shallower and stronger phytoplankton bloom. During upwelling, the highest chlorophyll- a concentrations (Chl>1 mg m -3) were observed in the upper 25 m with primary production rates exceeding 1800 mgC m -2 d -1. During the rainy season, a deep chlorophyll maximum (DCM, concentrations between 0.2 and 0.8 mg m -3) was observed between 35 and 55 m, with low (<0.2 mg m -3) Chl concentrations above this depth and primary production values of ˜990 mgC m -2 d -1. The DCM occurred immediately above the seasonal thermocline and around the 1% PAR light level. During the upwelling season, no DCM was observed.

  20. Physical characteristics of GE (General Electric) BWR (boiling-water reactor) fuel assemblies

    SciTech Connect

    Moore, R.S.; Notz, K.J.

    1989-06-01

    The physical characteristics of fuel assemblies manufactured by the General Electric Company for boiling-water reactors are classified and described. The classification into assembly types is based on the GE reactor product line, the Characteristics Data Base (CDB) assembly class, and the GE fuel design. Thirty production assembly types are identified. Detailed physical data are presented for each assembly type in an appendix. Descriptions of special (nonstandard) fuels are also reported. 52 refs., 1 fig., 6 tabs.

  1. Leaf anatomy and photosynthetic carbon metabolic characteristics in Phragmites communis in different soil water availability

    Microsoft Academic Search

    Chun-Mei GongJuan; Juan Bai; Jian-Ming Deng; Gen-Xuan Wang; Xi-Ping Liu

    2011-01-01

    To investigate the variations of anatomical and photosynthetic carbon metabolic characteristics within one species in response\\u000a to increasing soil water stress, leaf anatomical characteristics, gas exchange and the activity of key enzymes in photosynthesis\\u000a and photorespiration were compared in different ecotypes of Phragmites\\u000a communis growing in an oasis-desert transitional zone (ODTZ) from swamp habitat (plot 1–3) via heavy salt meadow

  2. Comparison of the physiological responses and time-motion characteristics of young soccer players in small-sided games: the effect of goalkeeper.

    PubMed

    Köklü, Yusuf; Sert, Özcan; Alemdaro?lu, Utku; Arslan, Yunus

    2015-04-01

    The purpose of this study was to investigate the effect of "with goalkeeper" (SSGwith) and "without goalkeeper" (SSGwithout) conditions on players' physiological responses and time-motion characteristics in small-sided games. Sixteen young soccer players (age: 16.5 ± 1.5 years; height: 175.5 ± 5.2 cm; body mass: 63.0 ± 6.9 kg; training experience: 6.3 ± 1.3 years) participated in 2 different 2-a-side, 3-a-side, and 4-a-side games: SSGwith and SSGwithout. The players underwent anthropometric measurements (height and body mass) followed by the Yo-Yo intermittent recovery test (level 1). Then they played 2-a-side, 3-a-side, and 4-a-side SSGwith and SSGwithout soccer-specific SSGs in random order at 2-day intervals. Heart rate (HR) responses and distance covered in different speed zones (walking [WLK, 0-6.9 km·h(-1)], low-intensity running [LIR, 7.0-12.9 km·h(-1)], moderate-intensity running [MIR, 13.0-17.9 km·h(-1)], and high-intensity running [HIR, >18 km·h(-1)]) were measured during the SSGs, whereas the rating of perceived exertion (RPE) and blood lactate (La) were determined at the end of the last bout of each SSG. During the SSGwithout players showed higher %HR, La, and RPE (p ? 0.05), greater distance covered in LIR, MIR, HIR, and total distance (p ? 0.05) compared with the SSGwith during the 2-a-side, 3-a-side, and 4-a-side games. The results of this study suggest that both SSGwith and SSGwithout could be used for the physiological adaptations required for soccer-specific aerobic endurance. However, if coaches want both higher physiological responses and greater distance covered in the intensity running zone from their teams, SSGwithout should be organized. In addition, this study also suggests that smaller format games (i.e., 2-a-side) may promote some anaerobic adaptations for youth soccer players. PMID:23942169

  3. Chemical and physical characteristics of natural ground waters in Michigan; a preliminary report

    USGS Publications Warehouse

    Cummings, T. Ray

    1980-01-01

    Wide variations occur in the chemical and physical characteristics of natural groundwaters in Michigan. Dissolved-solids concentrations range from 23 to 2,100 milligrams per liter. Waters having low dissolved-solids concentrations are calcium bicarbonate waters. Sodium, sulfate, and chloride increase as mineralization increases. Iron, aluminum, and titanium are higher at some locations than is common in most natural waters. Lead concentrations exceed those desirable in drinking water at some locations in the northern part of the Lower Peninsula. Generalized areal patterns of water quality variation suggest that geology is a primary cause of differences across the State. Examples of chemical associations in water suggest that chemical analyses may be valuable in tracing and identifying mineral deposits. (USGS)

  4. GIS and ordination techniques for studying influence of watershed characteristics on river water quality.

    PubMed

    Ou, Yang; Wang, Xiaoyan

    2011-01-01

    Landscape characteristics of twenty-eight sub-catchments within the Miyun reservoir watershed in Miyun County, northeast Beijing of China were examined to identify relationships with stream water chemistry. The influences of the entire catchment and 300 m buffer zone on water quality were compared using multiple regression analysis and redundancy analysis during three seasons. Results showed that strong seasonal differences in nitrate, nitrite and ammonium are observed whereas no difference in total phosphorus and conductivity. Landscape factors were significantly correlated to stream water quality. Residential area and stream density contributed markedly to river condition variability. Water quality was better explained by interactions with the landscape during and after rainy season. There was also a seasonal shift in the landscape factors that were the dominant explanatory variables. The relationships between landscape attributes and water quality on watershed scale were slightly different from those on riparian scale; however, landscape attributes may have stronger influences on water chemistry. PMID:22097072

  5. Experimental investigation of the silica gel–water adsorption isotherm characteristics

    Microsoft Academic Search

    K. C. Ng; H. T. Chua; C. Y. Chung; C. H. Loke; T. Kashiwagi; A. Akisawa; B. B. Saha

    2001-01-01

    In designing adsorption chillers that employs silica gel–water as adsorbent-adsorbate pair, the overriding objective is to exploit low temperature waste-heat sources from industry. This paper describes an experimental approach for the determination of thermodynamic characteristics of silica gel–water working pair that is essential for the sizing of adsorption chillers. The experiments incorporated the moisture balance technique, a control-volume-variable-pressure (CVVP) apparatus

  6. Experimental Study of Flammability Characteristics of 3Picoline\\/Water Under Various Initial Conditions

    Microsoft Academic Search

    Y. M. Chang; R. L. Yun; T. J. Wan; C. M. Shu

    2007-01-01

    Nicotinic acid (C6H5NO2), also known as vitamin B3 or niacin, can be produced from 3-picoline by direct oxidation with air and water vapour at high temperature. For safe handling of combustible or flammable substances, it is imperative to have an understanding of their safety-related flammability characteristic parameters. In this paper, 3-picoline\\/water mixtures ratios were varied over a wide range (5,

  7. Hydrological and water quality characteristics of three rock glaciers: Blanca Massif, Colorado, USA

    E-print Network

    DeMorett, Joseph Lawrence

    1989-01-01

    HYDROLOGICAL AND WATER QUALITY CHARACTERISTICS OF THREE ROCK GLACIERS: BLANCA MASSIF, COLORADO, USA A Thesis by JOSEPH LAWRENCE DEMORETT Submitted to the OIIice of Graduate Studies of Texas AdtM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1989 Major Subject: Geography HYDROLOGICAL AND WATER QUALITY CHARACIERISTICS OF THREE ROCK GLACIERS: BLANCA MASSIF, COLORADO, USA A Thesis by JOSEPH LAWRENCE DEMORETI' Approved as to style...

  8. Sprectroradiometric characteristics of inland water bodies infestated by Oscillatoria rubescens algae

    NASA Astrophysics Data System (ADS)

    Ciraolo, Giuseppe; La Loggia, Goffredo; Maltese, Antonino

    2010-10-01

    In December 2006 blooms of Oscillatoria rubescens were found in the reservoir Prizzi in Sicily. Oscillatoria is a genus of filamentous alga comprising approximately 6 species, between these the O. rubescens is sadly famous since this organism produces microcystins which are powerful hepatotoxins. Firstly found in Europe in 1825 on Geneva lake, recently (2006) those algae has been find out in Pozzillo, Nicoletti e Ancipa reservoirs (Enna Province), as well as in Prizzi (Palermo Province) and Garcia reservoirs (Trapani Province). Toxins produced by those bacteria (usually called microcystine LR-1 and LR-2) are highly toxic since they can activate oncogenes cells causing cancer pathologies on liver and gastrointestinal tract. Even if water treatment plants should ensure the provision of safe drinking water from surface waters contaminated with those toxic algae blooms, the contamination of reservoirs used for civil and agricultural supply highlights human health risks. International literature suggests a threshold value of 0.01 ?gl-1 to avoid liver cancer using water coming from contaminated water bodies for a long period. Since O. rubescens activities is strongly related to phosphate and nitrogen compounds as well as to temperature and light transmission within water, the paper presents the comparison between optical properties of the water of an infested reservoir and those of a reservoir characterized by clear water. Field campaigns were carried out in February-March 2008 in order to quantify the spectral transparencies of two water bodies through the calculation of the diffuse attenuation coefficient, measuring underwater downwelling irradiance at different depths as well as water spectral reflectance. Results show that diffuse attenuation coefficient is reduced by approximately 15% reducing light penetration in the water column; coherently reflectance spectral signature generally decreases, exhibiting a characteristic peak around 703 nm not present in uncontaminated waters. Latter findings highlight the possibility to detect O. rubescens infestations using their spectral characteristics by means of multitemporal remote sensing techniques.

  9. Spatial and seasonal patterns in stream water contamination across mountainous watersheds: Linkage with landscape characteristics

    NASA Astrophysics Data System (ADS)

    Ai, L.; Shi, Z. H.; Yin, W.; Huang, X.

    2015-04-01

    Landscape characteristics are widely accepted as strongly influencing stream water quality in heterogeneous watersheds. Understanding the relationships between landscape and specific water contaminant can greatly improve the predictability of potential contamination and the assessment of contaminant export. In this work, we examined the combined effects of watershed complexity, in terms of land use and physiography, on specific water contaminant across watersheds close to the Danjiangkou Reservoir. The land use composition, land use pattern, morphometric variables and soil properties were calculated at the watershed scale and considered potential factors of influence. Due to high co-dependence of these watershed characteristics, partial least squares regression was used to elucidate the linkages between some specific water contaminants and the 16 selected watershed characteristic variables. Water contaminant maps revealed spatial and seasonal heterogeneity. The dissolved oxygen values in the dry season were higher than those in the wet season, whereas the other contaminant concentrations displayed the opposite trend. The studied watersheds which are influenced strongly by urbanization, showed higher levels of ammonia nitrogen, total phosphorus, potassium permanganate index and petroleum, and lower levels of dissolved oxygen. The urban land use, largest patch index and the hypsometric integral were the dominant factors affecting specific water contaminant.

  10. [Ecological characteristic of benthic epipelic algae and the characteristic of water environment quality in heavily polluted river in city].

    PubMed

    Zhao, Zhen-hua; Ruan, Xiao-hong; Xing, Ya-nan; Ni, Li-xiao; Gao, Li-cun

    2009-12-01

    The water quality and algae community of Nanyuan Water System in the old city area of Suzhou were monitored for a year. Results showed that the water pollution in the studied area was mainly related to nitrogen (NH4+ -N and TN). Sometimes, they even exceeded the Environmental Quality Standards for Surface Water (GB 3838-2002, PRC) more than 5 times. 34 species of benthic epipelic algae were observed by microscope, and the species amount of diatom algae, green algae and blue algae are more than others. Their abundance and biomass are far higher than that of the pelagic algae in the same sites,and reach 2 145.5 x 10(4) cells/mL and 3.524 mg/mL,respectively. The dominant species of benthic epipelic algae in Nanyuan's water system are diatom algae and blue algae, most of which belong to the heterotrophic type or bi-trophic type algae, the typical genera include: Oscillaria amphibian (affiliated to Cyanophyta), Cyclotella sp., Melosira sp., Stephanodiscus hantzschii, Navicula sp., Nitzschia sp., Gomphonema (affiliated to Bacillariophyta) and so on. And their distribution of species and abundance are very nonuniform in different reach of heavily polluted city river, which relates to the pollutant characteristics of the river. The seasonal variety trend of the abundance for benthic algae showed that:summer > autumn > spring > winter, and that of biomass for benthic algae showed that: the biomass in winter is the most of four seasons and change extent of the biomass is not obvious in spring, summer and autumn. The research results can provide reference for the ecology restoration of city heavily polluted river. PMID:20187390

  11. WATER PROPERTIES IN FERN SPORES: SORPTION CHARACTERISTICS RELATING TO WATER AFFINITY, GLASSY STATES AND STORAGE STABILITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of ...

  12. Water properties in fern spores: sorption characteristics relating to water affinity, glassy states, and storage stability

    Microsoft Academic Search

    Daniel Ballesteros; Christina Walters

    2007-01-01

    Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of five homosporeous species of ferns and compared with properties of pollen, seeds, and fern

  13. Geometric characteristics and energy landscapes of halogen-water-hydrogen bridges at protein-ligand interfaces

    NASA Astrophysics Data System (ADS)

    Lu, Shao-Yong; Jiang, Yong-Jun; Zhou, Peng; Zou, Jian-Wei; Wu, Tian-Xing

    2010-01-01

    Halogen-water-hydrogen bridges (XWH bridges), in which one hydrogen bond (H-bond) in a traditional water-mediated H-bond bridge is replaced by a halogen bond (X-bond), is a novel mode of interaction for water in biological molecules. In this study, we investigate several protein-halogenated ligand complexes using a two-layer quantum mechanics/molecular mechanics (QM/MM) ONIOM method. Analysis of the geometric characteristics and energy behaviors of the complexes, together with the AIM results, indicate that XWH bridges are present in these systems. Furthermore, our investigations show that XWH bridges can have an important role in ligand recognition and binding.

  14. Water relation characteristics and photosynthesis of saline-stressed seedlings of non-halophyte species

    E-print Network

    Paris-Sud XI, Université de

    Water relation characteristics and photosynthesis of saline-stressed seedlings of non of the present study was to ex- amine the distribution of salts and its effect on photosynthesis for non as relative values against 0% treatment. Photosynthesis by O. asiaticus var. aurantiacus decreased

  15. CONNECTING WATERSHED CHARACTERISTICS TO NUTRIENT REGIME FROM HEADWATERS TO RECEIVING WATERS IN THE LAURENTIAL GREAT LAKES

    EPA Science Inventory

    We are evaluating the influence of position along the tributary-coastal wetland-lake continuum on the expression of watershed characteristics in the water quality of Great Lakes (GL) coastal ecosystems as part of an EPA study focused on determining stressor-response relationships...

  16. Aquifer characteristics and water quality of Miocene–Pleistocene sediments, Kuwait

    Microsoft Academic Search

    F. M. Al-Ruwaih; H. A. Qabazard

    2005-01-01

    Al-Atraf is one of the water well fields of Kuwait supplying Kuwait City with the brackish groundwater obtained from the Kuwait Group aquifer of Miocene–Pleistocene age. The study determined the hydrogeological and hydrochemical characteristics of the groundwater in order to identify the major chemical processes that influence the groundwater quality of the study area. The results of the aquifer test

  17. Research papers Bio-optical characteristics of Cariaco Basin (Caribbean Sea) waters

    E-print Network

    Meyers, Steven D.

    the chlorophyll-specific absorption coefficient, aà ph(440), was nearly half the value observed during the rainyResearch papers Bio-optical characteristics of Cariaco Basin (Caribbean Sea) waters Laura Lorenzoni December 2010 Available online 20 January 2011 Keywords: Cariaco Basin Bio-optical properties Chlorophyll

  18. Fouling characteristics and cleaning strategies in a coagulation-microfiltration combination process for water purification

    Microsoft Academic Search

    Li Mo; Xia Huanga

    2003-01-01

    The membrane fouling characteristics and cleaning strategies in a coagulation-microfiltration combination process for purification of micro-polluted raw water were investigated. The microcosmic observation on the exterior and inner surfaces of the fouled membrane by Scanning Electronic Microscope (SEM) combined. with Energy Dispersive Spectrometer (EDS) revealed that the fouling on the exterior surface was an integrated effect of microorganisms, organic and

  19. Effect of Void Distribution Parameter and Axial Power Profile on Boiling Water Reactor Bifurcation Characteristics

    Microsoft Academic Search

    D. D. B. van Bragt; Rizwan-uddin; T. H. J. J. van der Hagen

    2000-01-01

    Bifurcation analyses of the impact of the void distribution parameter Câ and the axial power profile on the stability of boiling water reactors (BWRs) are reported. Bifurcation characteristics of heated channels (without nuclear feedback) appear to be very sensitive to the axial power profile. A turning point bifurcation was detected for a (symmetrically) peaked axial power profile. This kind of

  20. Physiological responses of a cold-water shrimp, Pandalus borealis to bacterial lipopolysaccharide and synthetic double-stranded RNA, poly I:C

    Microsoft Academic Search

    Christopher Marlowe A. Caipang; Amod Kulkarni; Viswanath Kiron

    The effects of two pathogen-associated molecular patterns (PAMPs), namely, bacterial lipopolysaccharide (LPS) and double-stranded RNA, poly I:C on selected physiological response parameters in the hemolymph of a cold-water shrimp, Pandalus borealis were studied. Most of the tested immune factors were affected after intramuscular injection with the PAMPs. Total protein concentration in the hemolymph was significantly upregulated upon injection with the

  1. On using eco-physiological, micrometeorological and biogeochemical theory to evaluate carbon dioxide, water vapor and trace gas fluxes over vegetation: a perspective

    Microsoft Academic Search

    Dennis Baldocchi; Tilden Meyers

    1998-01-01

    How eco-physiological, biogeochemical and micrometeorological theory can be used to compute biosphere–atmosphere, trace gas exchange rates is discussed within the framework of a process model. The accuracy of the theory is tested by comparing computations of mass and energy flux densities (water vapor, sensible heat, CO2 and ozone) against eddy covariance measurements over five distinct canopies (wheat, potato and soybean

  2. The Spokane aquifer, Washington: its geologic origin and water-bearing and water-quality characteristics

    USGS Publications Warehouse

    Molenaar, Dee

    1988-01-01

    The Spokane aquifer is an unconfined aquifer consisting of coarse sand, gravel, cobbles, and boulders deposited during several catastrophic glacial outburst floods--known as the Spokane Floods---of Pleistocene time. The aquifer is one of the most productive in the United States, and, as the only significant source of good-quality water supply in the Spokane Valley, it has been designated as a 'Sole Source Aquifer' by the U.S. Environmental Protection Agency. The Spokane aquifer underlies an area of about 135 square miles in the Spokane Valley and varies in saturated thickness from a few feet to 500 feet or more. The aquifer is recharged by ground-water underflow from the Rathdrum Prairie aquifer in Idaho on the east, by ground-water underflow and surface-water seepage from small drainage areas along the Spokane Valley margins, and by percolation from various sources--from rainfall and snowmelt, from some reaches of the Spokane and Little Spokane Rivers, and from septic-tank drain fields, cesspools, and irrigation water. Discharge from the aquifer occurs by ground-water underflow from the lowermost end of the valley, by leakage to the Spokane and the Little Spokane Rivers, by evapotranspiration, and by ground-water withdrawal by pumping. The transmissivity of the aquifer ranges from less than 0.05 to 70 feet squared per second, and its specific yield ranges from less than 5 to 20 percent of the aquifer volume. Seasonal water-level fluctuations in wells tapping the aquifer are generally less than 10 feet. The annual pumpage from the aquifer in 1977 was about 164,000 acre-feet, of which about 70 percent was for municipal supplies, which included some industrial and commercial supplies. Land use over the aquifer includes predominantly agricultural activities in the eastern one-third of the valley and urban and residential developments in most of the remaining area. Potential sources of contamination of the aquifer include percolation from cesspools, septic-tank drain fields, and municipal and industrial waste-disposal sites. In general, the high rate of ground-water movement through the highly permeable aquifer materials has resulted in the ground-water quality being little affected by the overlying land use activities. Some local degradation of water quality has occurred due to industrial waste-disposal practices, however. During the water-quality study period of May 1977 to May 1978, average specific conductance of the ground water ranged from less than 100 to about 500 micromhos per centimeter at 25 degrees Celsius, average chloride concentration ranged from less than 2 to about 12 milligrams per liter (equivalent to parts per million}, and average nitrate nitrogen concentrations ranged from less than 1 to about 8 milligrams per liter. The streamflow and water quality of the Spokane River, which are related to the flow and quality of water in the Spokane aquifer, indicate that, during the period 1913 to 1978 inclusive, the river at Post Falls, Idaho, had an average annual discharge of 6,307 cubic feet per second, a maximum discharge of 50,100 cubic feet per second, and a minimum discharge of 65 cubic feet per second. The quality of the river water along its course through the study area is affected to some extent by inflows of industrial wastewater and treated municipal sewered water. In the 30-mile reach between the State line and Riverside State Park, during the 1975 to 1978 water years inclusive, concentrations of nearly all the constituents analyzed increased, and concentrations of dissolved oxygen correspondingly decreased from 1968 to 1977 inclusive; coliform bacteria also showed notable increases in the downstream direction.

  3. A study of ignition and combustion characteristics of isolated coal water slurry droplet using digital image processing technique

    E-print Network

    Bhadra, Tanmoy

    1998-01-01

    A digital image processing technique is used to investigate the ignition and combustion characteristics of an isolated coal water slurry droplet in low Re flow. Coal water slurry droplet study is useful for dilute coal suspensions based...

  4. Water properties in fern spores: sorption characteristics relating to water affinity, glassy states, and storage stability.

    PubMed

    Ballesteros, Daniel; Walters, Christina

    2007-01-01

    Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of five homosporeous species of ferns and compared with properties of pollen, seeds, and fern leaf tissue. Isotherms were constructed at 5, 25, and 45 degrees C and analysed using different physicochemical models in order to quantify chemical affinity and heat (enthalpy) of sorption of water in fern spores. Fern spores hydrate slowly but dry rapidly at ambient relative humidity. Low Brunauer-Emmet-Teller monolayer values, few water-binding sites according to the D'Arcy-Watt model, and limited solute-solvent compatibility according to the Flory-Huggins model suggest that fern spores have low affinity for water. Despite the low water affinity, fern spores demonstrate relatively high values of sorption enthalpy (DeltaH(sorp)). Parameters associated with binding sites and DeltaH(sorp) decrease with increasing temperature, suggesting temperature- and hydration-dependent changes in volume of spore macromolecules. Collectively, these data may relate to the degree to which cellular structures within fern spores are stabilized during drying and cooling. Water sorption properties within fern spores suggest that storage at subfreezing temperatures will give longevities comparable with those achieved with seeds. However, the window of optimum water contents for fern spores is very narrow and much lower than that measured in seeds, making precise manipulation of water content imperative for achieving maximum longevity. PMID:17283377

  5. Influence of multiple water-quality characteristics on copper toxicity to fathead minnows (Pimephales promelas)

    USGS Publications Warehouse

    Sciera, K.L.; Isely, J.J.; Tomasso, J.R., Jr.; Klaine, S.J.

    2004-01-01

    Water quality influences the bioavailability and toxicity of copper to aquatic organisms. Understanding the relationships between water-quality parameters and copper toxicity may facilitate the development of site-specific criteria for water quality and result in better protection of aquatic biota. Many studies have examined the influence of a single water-quality parameter on copper toxicity, but the interactions of several characteristics have not been well studied in low-hardness water. The goal of the present research was to examine the interactions among water-quality characteristics and their effects on copper toxicity to larval fathead minnows (Pimephales promelas). The effects of dissolved organic carbon (DOC) concentration, DOC source, pH, and hardness on acute copper toxicity were determined using a complete factorially designed experiment. Hardness, pH, DOC, and interaction of pH and DOC all significantly affected copper toxicity. A predictive model based on these data described 88% of the variability in copper toxicity. This model also explained 58% of the variability in copper toxicity for an independent dataset of South Carolina (USA) waters. The biotic ligand model underpredicted the acute copper toxicity to fathead minnows when compared with observed values.

  6. Water mass characteristics and geostrophic circulation in the South Brazil Bight: Summer of 1991

    NASA Astrophysics Data System (ADS)

    Campos, E. J. D.; GonçAlves, J. E.; Ikeda, Y.

    1995-09-01

    A hydrographic survey on board the German ship FS Victor Hensen was carried out in Brazilian coastal waters between Santos (23°56'S) and Rio de Janeiro (22°54'S) from January 15 to January 22, 1991. Analyses of conductivity-temperature-depth (CTD) data collected during this cruise show that the geostrophic flow and water mass structure of the Brazil Current in that region have characteristics similar overall to those in the better observed Cabo Frio region. The uppermost 200 m of the water column is dominated by the warm, highly saline Tropical Water flowing predominantly to the southwest. This flow direction appears to persist to approximately 900 m, the maximum depth reached by the CTD casts. The water lying between 250 and 750 m has the characteristics of South Atlantic Central Water (SACW). Below 750 m, down to 900 m, the water characteristics are those of Antarctic Intermediate Water. The thermohaline structure and geostrophic calculations indicate the presence of a meandering pattern, with a trough that appears to be the early stage of formation of a cold-core eddy over the upper slope region. This feature extends from the surface down to approximately 500 m depth and is apparently associated with the intrusion of SACW onto the continental shelf. The geostrophic computations (with respect to two reference levels, 750 and 900 dbar) yield maximum current values in the range 0.6-0.7 m s-1. The southwestward volume transport, averaged over the entire domain, was approximately 7.3 Sv with respect to 750 dbar and 8.8 Sv with respect to 900 dbar.

  7. The vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of kerosene

    NASA Astrophysics Data System (ADS)

    Liang, Jin-Hu; Wang, Su; Zhang, Sheng-Tao; Yue, Lian-Jie; Fan, Bing-Cheng; Zhang, Xin-Yu; Cui, Ji-Ping

    2014-08-01

    In ground tests of hypersonic scramjet, the high-enthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases: (1) clean gas, (2) gas vitiated with 10% and 20% water vapor in mole, (3) gas vitiated with 10% carbon dioxide in mole, and (4) gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when ? = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when ? = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at ? = 0.5, while no effect is found at ? = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.

  8. [Investigation of dynamic spectral characteristics of water in blood plasma hydrosols from breast cancer patients].

    PubMed

    Anichkov, N M; Manikhas, A G; Rozin, I T; Khaloimov, A I

    2006-01-01

    Our data on spectral characteristics of water in blood plasma hydrosols from breast cancer patients and healthy subjects are presented. A substantial difference between the two groups was found. As it was shown by us earlier, in breast cancer patients, as well as in other cancer patients, changes in spectral characteristics of water influence tissue hydrosols of the whole body. They persist even after tumor is radically removed. Such differences were probably linked to those in water molecular resonance frequencies. Using infrared spectroscopy, we confirmed the evidence available on carcinogenic (promoting) effect of both native and synthetic estrogens. It is suggested that healthy adult women have a certain "frequency immunity" which protects from the monthly autogenous promoting influences of estrogens. Our findings may contribute to devising further therapeutic frequency-assisted means of impacting on malignant tissue hydrosols. PMID:17168357

  9. Methods of rating unsaturated zone and watershed characteristics of public water supplies in North Carolina

    USGS Publications Warehouse

    Eimers, Jo Leslie; Weaver, J.C.; Terziotti, Silvia; Midgette, R.W.

    2000-01-01

    Overlay and index methods were derived for rating the unsaturated zone and watershed characteristics for use by the State of North Carolina in assessing more than 11,000 public water-supply wells and approximately 245 public surface-water intakes. The rating of the unsaturated zone and watershed characteristics represents a practical and effective means of assessing part of the inherent vulnerability of water supplies to potential contamination. Factors that influence the inherent vulnerability of the drinking water supply to potential contamination were selected and assigned ratings (on a scale of 1 to 10) to cover the possible range of values in North Carolina. These factors were assigned weights of 1, 2, or 3 to reflect their relative influence on the inherent vulnerability of the drinking water supply. The factor values were obtained from Geographic Information System data layers, and were transformed into grids having 60-meter by 60-meter cells, with each cell being assigned a value. Identification of factors, the development of ratings for each, and assignment of weights were based on (1) a literature search, which included examination of potential factors and their effects on the drinking water; and (2) consultation with experts in the science and engineering of hydrology, geology, forestry, agriculture, and water management. Factors selected for rating the inherent vulnerability of the unsaturated zone are vertical hydraulic conductance, land-surface slope, land cover, and land use. Vertical hydraulic conductance is a measure of the capacity of unsaturated material to transmit water. Land-surface slope influences whether precipitation runs off land surfaces or infiltrates into the subsurface. Land cover, the physical overlay of the land surface, influences the amount of precipitation that becomes overland flow or infiltrates into the subsurface. Land use describes activities that occur on the land surface and influence the potential generation of nonpoint-source contamination. Factors selected for rating the watershed characteristics upstream from surface-water intakes are average annual precipitation, land-surface slope, land cover, land use, and ground-water contribution. The average annual precipitation represents the mass of water that becomes available for transport in a watershed. Land-surface slope, land cover, and land use have similar influences in watersheds as those identified for the unsaturated zone. Ground-water contribution represents the part of streamflow that is derived from ground-water discharge.

  10. Global Modeling of Land Water and Energy Balances. Part II: Land-Characteristic Contributions to Spatial Variability

    Microsoft Academic Search

    P. C. D. Milly; A. B. Shmakin

    2002-01-01

    Land water and energy balances vary around the globe because of variations in amount and temporal distri- bution of water and energy supplies and because of variations in land characteristics. The former control (water and energy supplies) explains much more variance in water and energy balances than the latter (land charac- teristics). A largely untested hypothesis underlying most global models

  11. Work Capability and physiological effects predictive studies. 4: In He-O2 excursions to pressures of 400- 800- 1200- and 1600 feet of sea water

    NASA Technical Reports Server (NTRS)

    Lambertsen, C. J. (editor); Gelfand, R. (editor); Clark, J. M. (editor); Fletcher, M. E. (editor)

    1978-01-01

    Experiments which exposed men in chambers, breathing helium with oxygen, to progressive increases of pressure equivalent to 400-800-1200-1600 feet of sea water (fsw) were conducted. Rates of compression and exposure to stable high pressure. Goals included: 1) determination of the specific character and time course of onset of physiological and performance decrements during the intentionally rapid compressions, and determination of rates of adaptation on reaching stable elevated pressure; 2) investigation of accelerated methods for decompression in deep saturation excursion diving; and 3) determination of competence in practical work performed in water at pressures equivalent to the extreme diving depths of 1200 and 1600 fsw.

  12. Pore-size dependence and characteristics of water diffusion in slit-like micropores

    E-print Network

    S. O. Diallo

    2015-04-10

    The temperature dependence of the dynamics of water inside microporous activated carbon fibers (ACF) is investigated by means of incoherent elastic and quasi- elastic neutron scattering techniques. The aim is to evaluate the effect of increasing pore size on the water dynamics in these primarily hydrophobic slit-shaped channels. Using two different micropore sizes (\\sim 12 and 18 {\\AA}, denoted respectively ACF-10 and ACF-20), a clear suppression of the mobility of the water molecules is observed as the pore gap or temperature decreases. This suppression is accompanied by a systematic dependence of the average translational diffusion coefficient Dr and relaxation time of the restricted water on pore size and temperature. The observed Dr values are tested against a proposed scaling law, in which the translational diffusion coefficient Dr of water within a nanoporous matrix was found to depend solely on two single parameters, a temperature independent translational diffusion coefficient Dc associated with the water bound to the pore walls and the ratio {\\theta} of this strictly confined water to the total water inside the pore, yielding unique characteristic parameters for water transport in these carbon channels across the investigated temperature range.

  13. Effects of water addition on soil arthropods and soil characteristics in a precipitation-limited environment

    NASA Astrophysics Data System (ADS)

    Chikoski, Jennifer M.; Ferguson, Steven H.; Meyer, Lense

    2006-09-01

    We investigated the effect of water addition and season on soil arthropod abundance and soil characteristics (%C, %N, C:N, moisture, pH). The experimental design consisted of 24 groups of five boxes distributed within a small aspen stand in Saskatchewan, Canada. The boxes depressed the soil to create a habitat with suitable microclimate for soil arthropods, and by overturning boxes we counted soil arthropods during weekly surveys from April to September 1999. Soil samples were collected at two-month intervals and water was added once per week to half of the plots. Of the eleven recognizable taxonomic units identified, only mites (Acari) and springtails (Collembola) responded to water addition by increasing abundance, whereas ants decreased in abundance with water addition. During summer, springtail numbers increased with water addition, whereas pH was a stronger determinant of mite abundance. In autumn, springtails were positively correlated with water and negatively correlated with mites, whereas mite abundance was negatively correlated with increasing C:N ratio, positively correlated to water addition, and negatively correlated with springtail abundance. Although both mite and springtail numbers decreased in autumn with a decrease in soil moisture, mites became more abundant than springtails suggesting a predator-prey (mite-springtail) relationship. Water had a significant effect on both springtails and mites in summer and autumn supporting the assertion that prairie soil communities are water limited.

  14. Landscape characteristics impacts on water quality of urban lowland catchments: monitoring the Amsterdam city area

    NASA Astrophysics Data System (ADS)

    Yu, Liang; van der Vlugt, Corné; Rozemeijer, Joachim; Broers, Hans Peter; van Breukelen, Boris; Ouboter, Maarten; Stuyfzand, Pieter

    2015-04-01

    In Dutch lowland polder systems, groundwater quality significantly contributes to surface water quality. This process is influenced by landscape characteristics such as topography, geology, and land use types. In this study, 23 variables were selected for 144 polder catchments, including groundwater and surface water solute concentrations (TN, TP, NH4+, NO3-, HCO3-, SO42-, Ca2+, Cl-), seepage rate in mm per year, elevation, paved area percentage, surface water area percentage, and soil types (calcite, humus and lutum percentage). The spatial patters in groundwater and surface water quality can largely be explained by groundwater seepage rates in polders and partly by artificial redistribution of water via the regional surface water system. High correlations (R2 up to 0.66) between solutes in groundwater and surface water revealed their probable interaction. This was further supported by results from principal component analysis (PCA) and linear regression. The PCA distinguished four factors that were related to a fresh groundwater factor, seepage rate factor, brackish groundwater factor and clay soil factor. Nutrients (TP, TN, NH4+ and NO3-) and SO42- in surface water bodies are mainly determined by groundwater quality combined with seepage rate, which is negatively related to surface water area percentage and elevation of the catchment. This pattern is more obvious in deep urban lowland catchments. Relatively high NO3- loads more tend to appear in catchments with high humus, but low calcite percentage soil type on top, which was attributed to clay soil type that was expressed by calcite percentage in our regression. Different from nitrogen contained solutes, TP is more closely related to fresh groundwater quality than to seepage rate. Surface water Cl- concentration has a high relation with brackish groundwater. Due to the artificial regulation of flow direction, brackish inlet water from upstream highly influences the chloride load in surface water bodies downstream, especially in infiltrated urban catchments. We conclude that, apart from artificial regulation, groundwater has significant impacts on surface water quality in the polders. Especially in low-lying urban catchments surface water solute concentrations like TP, TN, NH4+, HCO3-, SO42-, and Ca2+ can be predicted by groundwater characteristics. These results suggest that groundwater quality plays a crucial role in understanding and improving surface water quality in regulated lowland catchments.

  15. Benchmarking the WaterGAP3 global hydrology model in reproducing streamflow characteristics

    NASA Astrophysics Data System (ADS)

    Eisner, Stephanie; Flörke, Martina

    2015-04-01

    Global hydrological models are key tools to understand and assess the current state of global freshwater resources. They facilitate quantifying the degree of human interference on the natural hydrological regime and help to assess impacts of global and climate change on water resources. Large to global scale hydrologic simulation is, however, prone to large uncertainties which originate from spatially distributed input data (atmospheric forcing and land surface parameters) and, in particular, the (often) simplified physical process representation. Most large-scale modelling approaches are constrained by the implicit assumption that one single model structure is globally valid and the fact that the modeler lacks location-specific knowledge. In order to evaluate the quality of water availability estimates and to quantify the uncertainty associated with these estimates, it is thus essential to examine systematically where and why large scale hydrological models perform well or poor in reproducing observed streamflow characteristics. This study presents an extensive benchmarking study of the WaterGAP3 (Water - Global Assessment and Prognosis) model to reproduce observed monthly stream characteristics on the basis of more than 2400 observed streamflow records globally. WaterGAP3 is a grid-based conceptual water balance model operating on a 5 arc minute global grid. The model is explicitly designed to account for human interference on the natural hydrologic regime through flow regulation and water abstractions. Monthly simulated discharges for the period 1958-2010 are evaluated against observations based on three complementary performance metrics. Subsequently, model performance is assessed against a set of generic catchment descriptors supported by available global datasets which characterize climatic and physiographic conditions in the individual catchments as well as the degree of human alteration of the hydrologic regime. These relationships between catchment characteristics and model efficiencies help to detect inadequacies in model structure as well as in the underlying input data, thus set the stage for further model development.

  16. [Distribution characteristics of organochlorine pesticides in surface water and sediments from the Mengjin wetland].

    PubMed

    Xiao, Chun-Yan; Tai, Chao; Zhao, Tong-Qian; Wu, Li; Zhou, Tian-Jian; Dong, Jing-Jing

    2009-06-15

    The surface water and sediments from the Mengjin wetland were collected. After seperated and concentrated by solid phase extraction and Soxhlet extraction, twenty kinds of organochlorine pesticides (OCPs) in the samples from the Mengjin wetland were analyzed by gas chromatography. In the surface water, 7 kinds of OCPs (incluing alpha-HCH, beta-HCH, gamma-HCH, delta-HCH, 4,4-DDT, heptachor and aldrin) were detected, with the detected ratio of 4.2% -62.5% and the content range of ND-12.21 ng/L. In the sediments, 4,4-DDE and 4,4-DDT were detected, with the detected ratio of 50%-75% and the content range of ND-64.58 ng/g. HCHs and DDTs in the surface water were both lower than the limited value defined by Environmental Quality Standards for Surface Water in China, while the surface sediments in the Mengjin wetland pose a bit high risk comparing with ERL and ERM value of risk evaluation. Distribution characteristics of OCPs components showed that HCHs usually had higher residue levels in surface water, while sediment was the fate of DDTs in the transfer process of materials from water to sediment. OCPs content in the surface water and sediments both decreased in the order of high water period > level water period > low water period. OCPs in the low water seasons were mainly the early residue, but OCPs in the high seasons had some new input in near term in the surface water and sediments. The results suggested that non-point source was one of the important sources of OCPs entering Mengjin wetland. PMID:19662839

  17. Preliminary assessment of chemical characteristics of DOC in surface waters of the Hulugou watershed, China

    NASA Astrophysics Data System (ADS)

    Zhou, M.; Zheng, Y.

    2013-12-01

    Climate warming induced permafrost melting has begun to exert considerable impact on watershed hydrology, including water quality. Study field is a low latitude alpine watershed with an area of 25 km2 in the northeastern part of the Qinghai-Tibetan Plateau. Water samples were collected from streams, seepage, and thermokarst ponds in July, 2012 (n=22) and July 2013 (n=35). For samples collected within the boundary of the watershed, the mean concentrations of DOC are 14.2, 0.6 and 0.14 mg/L for thermokarst water, seepage and stream waters, respectively. The FI (fluorescence index) provides information on organic matter source, with a value of 1.8~1.9 for microbially derived fulvic acids and a value of 1.2~1.4 for terrestrially derived fulvic acids. SUVA determined at 254nm is strongly correlated with percent aromaticity determined by 13C NMR. The thermokarst water with high DOC content and SUVA value displayed the lowest FI values with a mean close to 1.40. These characteristics are expected for terrestrial sourced DOC. The increasing FI values of the stream water collected within the watershed suggests increasing degree of influence of DOC from microbial processing. The pH, SUVA, DOC levels are comparable for seepage and stream waters, suggesting that they are of similar sources. However, seepage water had higher FI, suggesting that microbial processing of DOC that influenced stream and seepage water may have occurred subsurface. That the DOC in the stream and seepage waters are influenced by the subsurface biogeochemical processes is supported by high RI values, because hyporheic exchange has likely brought reduced fulvic acids from the hyporheic zone into the stream. The data suggest the permafrost melt water not only has high concentrations of DOC but also displays a unique chemical signature. Further work combined with stable isotope analysis will help to illuminate the processes and to resolve the contribution of water and DOC from permafrost melting to streams.

  18. Chemical characteristics of Central Indian Basin waters during the southern summer

    NASA Astrophysics Data System (ADS)

    de Sousa, S. N.; Sardessai, S. D.; Babu, V. Ramesh; Murty, V. S. N.; Gupta, G. V. M.

    Chemical properties of the water column were examined at the Indian Deep-sea Environment Experiment (INDEX) site in the Central Indian Basin (CIB), as a part of baseline studies prior to the benthic disturbance experiment for the environmental impact assessment of mining of polymetallic nodules. The study shows three equatorward moving water masses. (a) The Subsurface Salinity Maximum in the depth range 125-200 m, characterized by high salinity (34.74-34.77 psu) and oxygen minimum associated with weak maxima in nutrients. (b) The Deep Oxygen Maximum (234-245 ?M) in the depth range 250-750 m, associated with minima in nutrients and relatively high pH. (c) The Salinity Minimum Water (34.714-34.718 psu) corresponding to the Antarctic Intermediate Water (AAIW) at depths 800-1200 m in the density ( ??) range 27.2-27.5. Progressive changes in these characteristics are attributed to mixing with waters above and below, and to oxidation of organic detritus en route. Among the three water masses, the oxygen maximum water shows the lowest changes in its properties, which may suggest that this water mass is moving the fastest.

  19. Seabed characteristics from ambient noise at three shallow water sites in Northern Indian Ocean.

    PubMed

    Sanjana, M C; Latha, G; Mahanty, M M

    2013-10-01

    Ambient noise measurements at three sites along the Indian continental shelf, with different water column and seabed, are analyzed to derive vertical directionality and further estimation of seabed characteristics. Directionality pattern is interpreted using features in the sound speed profiles, in terms of noise notch, surface duct, surface bottom reflections, direct arrivals, and high bottom loss arrivals. Reflection loss estimated from the field directionality is seen to be the same for a particular site and gives an estimate of the sea bottom. Seabed characteristics such as critical angle and reflection coefficient from field directionality correlate well with theoretical estimation using ground truths. PMID:24116544

  20. Water use and physiology of the riparian tree species Eucalyptus victrix in the semi-arid Pilbara region of Western Australia

    NASA Astrophysics Data System (ADS)

    Pfautsch, S.; Keitel, C.; Adams, M. A.; Turnbull, T.

    2009-04-01

    We examined the water use and physiology of trees growing in a riparian community within the seasonally arid Pilbara region of north-western Australia. This region is arid during the winter months, but monsoonal during summer (November to April). Maximum monthly mean temperatures in summer exceed 40 °C and are c. 25 °C during the winter months. The Millstream study site is located on a section of the Fortescue River system along the base of the Chichester Range c. 100km south of Karratha. This system creates a unique landscape in the Pilbara as it forms several large permanent pools. These pools are maintained by springs from an aquifer beneath the alluvial plain. The groundwater from this aquifer is used as a public water supply for towns in the west Pilbara but industrial development and a growing population will place greater demand on this aquifer. Changes to the local hydrology may have dramatic effects on the local plant community, dominated variously by stands of Eucalyptus victrix (Coolibah) and Eucalyptus camaldulensis (River red gum). This study seeks to understand the dependence of the Millstream riparian ecosystem on the height of the aquifer and to characterise the water use and physiology of Eucalyptus victrix. We used a number of techniques to determine the hydraulic and photosynthetic status of the tree canopy, including isotope, sap flow, water-potential and gas exchange measurements. Initial results from this study show: a) Soil water d18O and d2H is strongly enriched towards the surface, which coincides with a strong increase in salinity. The water source accessed by these trees has been identified by d18O and d2H analysis of xylem water. d18O and d2H were additionally analysed in atmospheric and leaf water pools. b) Sap flow in Coolibah trees shows a unique pattern of sharp early morning rise to a plateau maintained throughout the hottest part of the day, followed by a sharp decline in flow late in the afternoon. c) Leaf water potential follows a similar pattern to sap flow with changes of c. 1 MPa (from c. 0.5 MPa to 1.5 MPa) within 45 min at the beginning and the end of the light period. d) Stomatal conductance appears to be disconnected from this pattern and shows a slower opening phase in the morning, no discernible midday-afternoon depression and a slower closure in the evening, well after night-fall. Combining isotopic, sap flow, physiological and meteorologic information will help to understand how these riparian ecosystems function and how they respond to rapid environmental changes, both natural and introduced by human activities.

  1. Predicting river water quality across North West England using catchment characteristics

    NASA Astrophysics Data System (ADS)

    Rothwell, J. J.; Dise, N. B.; Taylor, K. G.; Allott, T. E. H.; Scholefield, P.; Davies, H.; Neal, C.

    2010-12-01

    SummaryLinear relationships between regional water quality and catchment characteristics (terrain, land cover, geology, base flow index and rainfall) are examined for rivers in North West England using a GIS-based approach and an extensive Environment Agency water quality database. The study considers the role of diffuse and distal point sources on river water quality. The results show that base cation concentrations are strongly linked to catchment terrain and land cover, while pH is linked to bedrock geology and land cover. Mean nitrate concentrations are most strongly related to arable cover, although distal point sources in urban and rural catchments appear to have a significant effect on river nitrate concentrations in the region. Orthophosphate and suspended sediment concentrations are most closely related to the percentage urban development. Linear models are tested on a large independent water quality dataset, resulting in maps showing predicted water quality across the region. The approach works well for the prediction of nitrate concentrations and other constituents which have predominantly diffuse sources. In contrast, the linear approach to predicting orthophosphate concentrations in North West rivers using catchment characteristics is problematic. The major influence of point sources may mask the effect of wider basin attributes on orthophosphate concentrations. Within-river processing of phosphorus may also explain why the relationship breaks down. Further work is needed to explain phosphorus contributions and variability in North West rivers, especially in the context of effective catchment management.

  2. Identification of characteristic regions and representative stations: a study of water quality variables in the Kattegat.

    PubMed

    Danielsson, A; Rahm, L; Conley, D J; Carstensen, J

    2004-01-01

    Gradients in nutrient distributions and the effects of eutrophication are common features in most coastal marine areas. These structures occur in aquatic systems due to spatial differences in hydrography, nutrient loading and key biogeochemical processes. Two statistical methods, cluster analysis and probability mapping, have been used in the present study to determine characteristics and patterns in water quality variables. Combined, these two methods provide a useful tool to statistically determine spatial homogeneity and representativity of areas and stations. A case study is presented here in which water quality variables (salinity, dissolved inorganic nitrogen, dissolved inorganic phosphorus and chlorophyll) in surface waters of the Kattegat are analysed for the time period 1993-1997. It was found that morphology, the proximity to sources of nutrient loading from land, nutrient uptake and the infrequent water exchange between the Baltic Sea in the south and the Skagerrak in the north all contribute to create distinct regions of water quality. Regions with concentrations significantly different from the overall mean are identified. In addition to identification of regions with similar characteristics, representative stations (as well as not representative stations) for the respective regions were made. This type of information can be used to design new or revise old monitoring programs. PMID:15887373

  3. Selected basin characteristics and water-quality data of the Minnesota River basin

    USGS Publications Warehouse

    Winterstein, T.A.; Payne, G.A.; Miller, R.A.; Stark, J.R.

    1993-01-01

    Selected basin characteristics and water-quality dam for the Minnesota River Basin are presented in this report as 71 maps, 22 graphs, and 8 tables. The data were compiled as part of a four-year study to identify non-point sources of pollution and the effect of this pollution on water quality. The maps were prepared from geographic information system data bases. Federal, State, and local agencies, and colleges and universities collected and assembled these data as part of the Minnesota River Assessment Project.

  4. The Effect of Heat on Structural Characteristics and Water Absorption Behavior of Agave Fibers

    NASA Astrophysics Data System (ADS)

    Saikia, Dip

    2008-04-01

    The structural characteristics and water absorptions behavior agave fibers were investigated over a range of temperature by using XRD, IR, TG and gravimetric methods. Three distinct thermal processes were observed during heating the fiber in the temperature range 310-760 K in air, oxygen and nitrogen invariably. The cellulose structures of the fibers were unaffected on heating up to 450 K. The samples showed thermal decomposition processes beyond 500 K. Fibers displayed a two-stage diffusion behavior. The structural parameters and kinetic of water absorption of the fibers at specific temperatures were analyzed.

  5. Denitrification of brackish water by electrodialysis: Effect of process parameters and water characteristics

    Microsoft Academic Search

    Mourad Ben Sik Ali; Amine Mnif; Bechir Hamrouni; Mahmoud Dhahbi

    2010-01-01

    The aim of this work is to study the removal of nitrate from brackish polluted water using electrodialysis. The influence\\u000a of several parameters, such as flow rates, initial feed concentration, co-existing anions and initial pH on process efficiency\\u000a were studied. This efficiency is evaluated by the removal rate, demineralization rate and power consumption. The denitrification\\u000a process showed to be independent

  6. Microgravity Alters the Physiological Characteristics of Escherichia coli O157:H7 ATCC 35150, ATCC 43889, and ATCC 43895 under Different Nutrient Conditions

    PubMed Central

    Kim, H. W.; Matin, A.

    2014-01-01

    The aim of this study is to provide understanding of microgravity effects on important food-borne bacteria, Escherichia coli O157:H7 ATCC 35150, ATCC 43889, and ATCC 43895, cultured in nutrient-rich or minimal medium. Physiological characteristics, such as growth (measured by optical density and plating), cell morphology, and pH, were monitored under low-shear modeled microgravity (LSMMG; space conditions) and normal gravity (NG; Earth conditions). In nutrient-rich medium, all strains except ATCC 35150 showed significantly higher optical density after 6 h of culture under LSMMG conditions than under NG conditions (P < 0.05). LSMMG-cultured cells were approximately 1.8 times larger than NG-cultured cells at 24 h; therefore, it was assumed that the increase in optical density was due to the size of individual cells rather than an increase in the cell population. The higher pH of the NG cultures relative to that of the LSMMG cultures suggests that nitrogen metabolism was slower in the latter. After 24 h of culturing in minimal media, LSMMG-cultured cells had an optical density 1.3 times higher than that of NG-cultured cells; thus, the higher optical density in the LSMMG cultures may be due to an increase in both cell size and number. Since bacteria actively grew under LSMMG conditions in minimal medium despite the lower pH, it is of some concern that LSMMG-cultured E. coli O157:H7 may be able to adapt well to acidic environments. These changes may be caused by changes in nutrient metabolism under LSMMG conditions, although this needs to be demonstrated in future studies. PMID:24487539

  7. Physiological and isotopic characteristics of nitrogen fixation by hyperthermophilic methanogens: Key insights into nitrogen anabolism of the microbial communities in Archean hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Nishizawa, Manabu; Miyazaki, Junichi; Makabe, Akiko; Koba, Keisuke; Takai, Ken

    2014-08-01

    Hyperthermophilic hydrogenotrophic methanogens are considered to be one of the most predominant primary producers in hydrogen (H2)-abundant hydrothermal environments in the present-day ocean and throughout the history of the Earth. However, the nitrogen sources supporting the development of microbial communities in hydrothermal environments remain poorly understood. We have investigated, for the first time, methanogenic archaea commonly found in deep-sea hydrothermal environments to understand their physiological properties (growth kinetics, energetics, and metal requirements) and isotopic characteristics during the fixation of dinitrogen (N2), which is an abundant but less-bioavailable compound in hydrothermal fluids. Culture experiments showed that Methanocaldococcus strain (Mc 1-85N) (Topt = 85 °C) and Methanothermococcus strain (Mt 5-55N) (Topt = 55 °C) assimilated N2 and ammonium, but not nitrate. Previous phylogenetic studies have predicted that the Methanocaldococcus and Methanothermococcus lineages have nitrogenases, key enzymes for N2 fixation, with biochemically uncharacterised active site metal cofactors. We showed that Mt 5-55N required molybdenum for the nitrogenase to function, implying a molybdenum-bearing cofactor in the strain. Molybdenum also stimulated diazotrophic (i.e., N2-fixing) growth of Mc 1-85N, though further experiments are required to test whether the strain contains a molybdenum-dependent nitrogenase. Importantly, Mc 1-85N exhibited an apparently lower requirement of and higher tolerance to molybdenum and iron than Mt 5-55N. Furthermore, both strains produced more 15N-depleted biomass (-4‰ relative to N2) than that previously reported for diazotrophic photosynthetic prokaryotes. These results demonstrate that diazotrophic hyperthermophilic methanogens can be broadly distributed in seafloor and subseafloor hydrothermal environments, where the availability of transition metals is variable and where organic carbon, organic nitrogen, and ammonium are generally scarce. The emergence and function of diazotrophy, coupled with methanogenesis, in the early Earth is also consistent with the nitrogen isotopic records of 3.5 billion-year-old hydrothermal deposits.

  8. [Analysis of the characteristics of corrosion scale in drinking water distribution systems].

    PubMed

    Niu, Zhang-bin; Wang, Yang; Zhang, Xiao-jian; He, Wen-jie; Han, Hong-da; Yin, Pei-jun

    2006-06-01

    Scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze the microstructure, chemical composition, crystalline structure and compound constitute of the corrosion scale from cast iron pipe and galvanized steel pipe in drinking water distribution systems. The outer of the corrosion scale was compact, while the inner was porous. Iron was the primary chemical element of the corrosion scale, and the composition of the scale was iron compounds. The outer scale were ferric compounds such as alpha-FeOOH, gamma-FeOOH, alpha-Fe2O3, gamma-Fe2O3, FeCl3, while the inner were ferrous compounds such as Fe3O4, FeCl2, FeCO3. The characteristics of the corrosion scale was lying on hydraulic conditions and water quality in distribution systems, and the characteristics of iron pipe materials. PMID:16921952

  9. Interfacial characteristics of ?-casein spread films at the air–water interface

    Microsoft Academic Search

    Ma Rosario Rodr??guez Niño; Cecilio Carrera Sánchez; Juan M. Rodr??guez Patino

    1999-01-01

    Casein is well known to be a good protein emulsifier and ?-casein is the major component of casein and commercial sodium caseinate. This work studies the behaviour of ?-casein at the interface. The interfacial characteristics (structure and stability) of ?-casein spread films have been examined at the air–water interface in a Langmuir-type film balance, as a function of temperature (5–40°C)

  10. Comparative investigation of chemical and biological characteristics in waters and trophic state of Mongolian lakes

    Microsoft Academic Search

    Osamu Mitamura; Darijav Khadbaatar; Noriko Ishida

    2010-01-01

    The objective of this study is to describe the biogeochemical characteristics in the waters of Mongolian lakes, particularly\\u000a those related to parameters limiting phytoplankton growth and the trophic state. Investigations into the distribution of chemical\\u000a and biological parameters were carried out in the following 18 lakes: Har Us, Har, Hovsgol, Achit, Dalai, Bayan, Tolbo, Holboo,\\u000a Bust, Sangiyn Dalai, Tunamal, Dorgon,

  11. Preparation and characteristic of triolein-embedded composite sorbents for water purification

    Microsoft Academic Search

    Jinxian Huo; Huijuan Liu; Jiuhui Qu; Zijian Wang; Jiantuan Ge; Haining Liu

    2005-01-01

    The novel triolein-embedded composite sorbents for removing persistent organic pollutants (POPs) in water were developed. Comprehensive structural characteristics of the composite sorbents were characterized using scanning electron microscope (SEM), fourier transform infrared spectrum (FT-IR) and X-ray photoelectron spectrum (XPS). It is suggested that triolein\\/cellulose acetate (CA) viscous syrup can be deposited on the surface of silica gel granules, because the

  12. RESEARCH: Land Use Characteristics and Water Quality: A Methodology for Valuing of Forested Buffers

    Microsoft Academic Search

    Prakash Basnyat; Lawrence Teeter; B. Graeme Lockaby; Kathryn M. Flynn

    2000-01-01

      \\u000a In this study, water quality and basin characteristics data from different basins of the Fish River basin, Baldwin County,\\u000a Alabama, were used to develop a valuation model. This valuation model is based on the effectiveness of “contributing zones”\\u000a identified and delineated using methods described by Basnyat and others (Environmental Management]1999] 23(4):539–549). The “contributing zone” delineation model suggests that depending

  13. Convective heat transfer and flow characteristics of Cu-water nanofluid

    Microsoft Academic Search

    Qiang Li; Yimin Xuan

    2002-01-01

    An experimental system is built to investigate convective heat transfer and flow characteristics of the nanofluid in a tube.\\u000a Both the convective heat transfer coefficient and friction factor of Cu-water nanofluid for the laminar and turbulent flow\\u000a are measured. The effects of such factors as the volume fraction of suspended nanoparticles and the Reynolds number on the\\u000a heat transfer and

  14. Chemical and physical characteristics of water in estuaries of Texas, October 1976-September 1978

    USGS Publications Warehouse

    Fisher, J.C.

    1982-01-01

    This report presents basic data on the chemical and physical characteristics of water in the estuaries of Texas for the period October 1976-September 1978. The properties or constituents that are measured in the field are dissolved oxygen (DO), specific conductance, temperature, pH, and transparency by Secchi disk. Analyses conducted in the laboratory include the principal inorganic ions, biochemical oxygen demand (BOD), total organic carbon (TOC), ammonium, nitrite, nitrate, and total phosphate. (USGS)

  15. River basin water resource compensation characteristics by set pair analysis: the Dongjiang example

    NASA Astrophysics Data System (ADS)

    Chen, Qiuwen; Li, Jing; Li, Ruonan; Wei, Wenda; Wang, Liming

    2014-03-01

    Flood and drought coexist in many river basins, thus analyses of water resource compensation characteristics become important, since they are the foundation for rational utilization of floodwaters. In this research, set pair analysis (SPA), a relatively new uncertainty analysis method, is used to study the dry and wet compensation characteristics of water resource parameters. In addition, fuzzy membership and grey correlation degree are adopted to test the result of set pair analysis. The Dongjiang River is taken as an example and the analyzed parameters include precipitation and mean discharge from different hydrological stations. The results show that there is a high homeotype-encountering chance for precipitation and mean discharge between different stations for both dry and wet conditions; thus the compensation capacity is small. Although the mean discharge is synchronous with the precipitation in the river basin, there exists a certain degree of shift, indicating possible utilization of floodwater on a small scale. The results from SPA are consistent with that from a traditional analysis method, showing that SPA is a promising alternative method for studying river basin water resource compensation characteristics, in particular for exploring potential complements embedded in noncomplementary general features.

  16. Performance Evaluation of Four-Parameter Models of the Soil-Water Characteristic Curve

    PubMed Central

    Taha, Mohd Raihan

    2014-01-01

    Soil-water characteristic curves (SWCCs) are important in terms of groundwater recharge, agriculture, and soil chemistry. These relationships are also of considerable value in geotechnical and geoenvironmental engineering. Their measurement, however, is difficult, expensive, and time-consuming. Many empirical models have been developed to describe the SWCC. Statistical assessment of soil-water characteristic curve models found that exponential-based model equations were the most difficult to fit and generally provided the poorest fit to the soil-water characteristic data. In this paper, an exponential-based model is devised to describe the SWCC. The modified equation is similar to those previously reported by Gardner (1956) but includes exponential variable. Verification was performed with 24 independent data sets for a wide range of soil textures. Prediction results were compared with the most widely used models to assess the model's performance. It was proven that the exponential-based equation of the modified model provided greater flexibility and a better fit to data on various types of soil. PMID:24971384

  17. Performance evaluation of four-parameter models of the soil-water characteristic curve.

    PubMed

    Matlan, Siti Jahara; Mukhlisin, Muhammad; Taha, Mohd Raihan

    2014-01-01

    Soil-water characteristic curves (SWCCs) are important in terms of groundwater recharge, agriculture, and soil chemistry. These relationships are also of considerable value in geotechnical and geoenvironmental engineering. Their measurement, however, is difficult, expensive, and time-consuming. Many empirical models have been developed to describe the SWCC. Statistical assessment of soil-water characteristic curve models found that exponential-based model equations were the most difficult to fit and generally provided the poorest fit to the soil-water characteristic data. In this paper, an exponential-based model is devised to describe the SWCC. The modified equation is similar to those previously reported by Gardner (1956) but includes exponential variable. Verification was performed with 24 independent data sets for a wide range of soil textures. Prediction results were compared with the most widely used models to assess the model's performance. It was proven that the exponential-based equation of the modified model provided greater flexibility and a better fit to data on various types of soil. PMID:24971384

  18. Anchoring of aquaporin-4 in brain: Molecular mechanisms and implications for the physiology and pathophysiology of water transport

    Microsoft Academic Search

    M. Amiry-Moghaddam; D. S. Frydenlund; O. P. Ottersen

    2004-01-01

    Astrocytes show an enrichment of aquaporin-4 (AQP4) in those parts of the plasma membrane that are apposed to pial or perivascular basal laminae. This observation begged the following questions: 1, What are the molecular mechanisms that are responsible for the site specific anchoring of AQP4? 2, What are the physiological and pathophysiological roles of the AQP4 pools at these specialized

  19. Seasonal variations of physiological and cellular biomarkers and their use in the biomonitoring of north adriatic coastal waters (Croatia)

    Microsoft Academic Search

    S. Petrovi?; L. Semen?i?; B. Ozreti?; M. Ozreti?

    2004-01-01

    Lysosomal membrane stability, the content of neutral lipids and lipofuscin as cellular biomarkers were measured in the digestive gland of mussels, Mytilus galloprovincialis Lam., during a one year survey at selected sites along the coast of the northern Adriatic. The ability of mussels to survive in air as a general physiological response was tested at the same sites. Annual changes

  20. Effect of seedling age and water depth on morphological and physiological aspects of transplanted rice under high temperature

    Microsoft Academic Search

    KHAKWANI Abdul Aziz; SHIRAISHI Masaaki; ZUBAIR Muhammad; BALOCH Mohammad Safdar; NAVEED Khalid; AWAN Inayatullah

    To study the effect of high temperature, rice seedlings 20, 30, 40 and 50 d were kept at 5, 10, 15 and 20 cm water depth in a water pool. Meteorological findings indicated that water temperature varied up to 10 cm but became stable below this depth. Deep water inflicted higher tiller mortality, minimal increase in dry weight of aerial

  1. Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer

    E-print Network

    Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap over a lay- ered elastic seabed with a shear wave speed comparable to but lower than the water frequencies which in turn are governed primarily by the water depth and compressional wave speed in the seabed

  2. Morphological and physiological indicators of water stress in Rosa multiflora and its effect on T-bud grafting procedure 

    E-print Network

    Palacios Gilliland, Miguel Angel

    1989-01-01

    means; non-stress (NoS), intermediate (IS), and stressed (S) and watered with 300, 150, and 120 ml every 2 days respectively. Higher leaf water potentials ('y) as well as transpiration rates (E), stomatal conductance (g, ), and relative water content... tissue elasticity and lead to a smaller change in relative water content per unit decrease in water potential (Turner, 1979). Stomatal aperture greatly influences moisture loss through control of transpiration processes. Stomata of roses are known...

  3. Location and site characteristics of the ambient ground-water-quality-monitoring network in West Virginia

    USGS Publications Warehouse

    Kozar, M.D.; Brown, D.P.

    1995-01-01

    Ground-water-quality-monitoring sites have been established in compliance with the 1991 West Virginia "Groundwater Protection Act." One of the provisions of the "Groundwater Protection Act" is to conduct ground-water sampling, data collection, analyses, and evaluation with sufficient frequency so as to ascertain the characteristics and quality of ground water and the sufficiency of the ground- water protection programs established pursuant to the act (Chapter 20 of the code of West Virginia, 1991, Article 5-M). Information for 26 monitoring sites (wells and springs) which comprise the Statewide ambient ground-water-quality-monitoring network is presented. Areas in which monitoring sites were needed were determined by the West Virginia Division of Environmental Protection, Office of Water Resources in consultation with the U.S. Geological Survey (USGS). Initial sites were chosen on the basis of recent hydrogeologic investigations conducted by the USGS and from data stored in the USGS Ground Water Site Inventory database. Land use, aquifer setting, and areal coverage of the State are three of the more important criteria used in site selection. A field reconnaissance was conducted to locate and evaluate the adequacy of selected wells and springs. Descriptive information consisting of site, geologic, well construction, and aquifer-test data has been compiled. The 26 sites will be sampled periodically for iron, manganese, most common ions (for example, calcium, magnesium, sodium, potassium, sulfate, chloride, bicarbonate), volatile and semivolatile organic compounds (for example, pesticides and industrial solvents), and fecal coliform and fecal streptococcus bacteria. Background information explaining ground-water systems and water quality within the State has been included.

  4. Physiological Genomics

    NSDL National Science Digital Library

    1969-12-31

    Five journals with free (or recently extended) online trial periods were recently announced; online content includes full text, figures, and tables. The American Physiological Society has announced free, online access to Physiological Genomics through December 31, 2001; full text and abstracts are available from 1999. The journal is published in conjunction with Stanford University's HighWire Press.

  5. Transient characteristics of a grooved water heat pipe with variable heat load

    NASA Technical Reports Server (NTRS)

    Jang, Jong Hoon

    1990-01-01

    The transient characteristics of a grooved water heat pipe were studied by using variable heat load. First, the effects of the property variations of the working fluid with temperature were investigated by operating the water heat pipe at several different temperatures. The experimental results show that, even for the same heat input profile and heat pipe configuration, the heat pipe transports more heat at higher temperature within the tested temperature range. Adequate liquid return to the evaporator due to decreasing viscosity of the working fluid permits continuous vaporization of water without dry-out. Second, rewetting of the evaporator was studied after the evaporator had experienced dry-out. To rewet the evaporator, the elevation of the condenser end was the most effective way. Without elevating the condenser end, rewetting is not straight-forward even with power turned off unless the heat pipe is kept at isothermal condition for sufficiently long time.

  6. Types and characteristics of drinking water for hydration in the elderly.

    PubMed

    Casado, Ángela; Ramos, Primitivo; Rodríguez, Jaime; Moreno, Norberto; Gil, Pedro

    2015-10-15

    The role of hydration in the maintenance of health is increasingly recognized. Hydration requirements vary for each person, depending on physical activity, environmental conditions, dietary patterns, alcohol intake, health problems, and age. Elderly individuals have higher risk of developing dehydration than adults. Diminution of liquid intake and increase in liquid losses are both involved in causing dehydration in the elderly. The water used for drinking is provided through regular public water supply and the official sanitary controls ensure their quality and hygiene, granting a range of variation for most of its physical and chemical characteristics, being sometimes these differences, though apparently small, responsible for some disorders in sensitive individuals. Hence, the advantages of using bottled water, either natural mineral water or spring water, are required by law to specify their composition, their major components, and other specific parameters. It is essential to take this into account to understand the diversity of indications and favorable effects on health that certain waters can offer. PMID:24915336

  7. Benthic invertebrate population characteristics as affected by water quality in coal-bearing regions of Tennessee

    USGS Publications Warehouse

    Bradfield, A.D.

    1986-01-01

    Benthic invertebrate and water quality data collected during previous U.S. Geological Survey studies to provide background hydrologic information on streams draining Tennessee coal reserves, were evaluated to identify possible relations between stream biota and water quality. Linear regressions produced low correlation coefficients relating the number of taxa/sample, total number of organisms/sample, sample diversity, and percentage composition of selected orders of invertebrates, with average water quality parameter values available at sampling stations (r is < 0.62 at p=0.05). Analyses of these data by linear regressions explained little of the variability in benthic invertebrate samples primarily because the distributions of benthic organisms along environmental gradients are nonlinear. Variability in substrate characteristics in the study area and seasonal insect emergence patterns also complicated interpretation of these data. However, analysis of variance tests did indicate significant trends towards reduced number of taxa, number of organisms, and sample diversity at stations with relatively poor water quality conditions. Decreasing percentage composition of Ephemeroptera was generally accompanied by an increase in percent Diptera at stations with higher water quality constituent concentrations and acidic pH ( > than 0.6 units). These trends indicate significant differences in benthic communities at sites with evidence of more severe land use impacts. Additional data on benthic invertebrates, water quality , and physical habitat conditions, along with analyses of data using multivariate statistical methods are needed to define ecological relations between specific groups of invertebrates and environmental conditions. (Author 's abstract)

  8. [Impact of wind-water alternate erosion on the characteristics of sediment particles].

    PubMed

    Tuo, Deng-Feng; Xu, Ming-Xiang; Ma, Xin-Xin; Zheng, Shi-Qing

    2014-02-01

    Wind and water are the two dominant erosion agents that caused soil and water losses in the wind-water alternate erosion region on the Loess Plateau. It is meaningful to study the impact of wind-water alternate erosion on the characteristics of soil particles for understanding the response of soil quality and environment to erosion. Through wind tunnel combined rainfall simulation, this paper studied the characteristics of the erosive sediment particles under the effect of wind-water alternate erosion. The results showed that the particles of 0-1 cm soil were coarsened by wind erosion at the wind speeds of 11 and 14 m x s(-1) compared with no wind erosion. Soil fine particles (< 0.01 mm) decreased by 9.8%-10.8%, and coarse particles (> 0.05 mm) increased by 16.8%-20.8%. The physical property of surface soil was changed by the wind erosion, which, in turn, caused an increase in finer particles content in the sediment. Compared with no wind erosion, fine particles (< 0.01 mm) in sediment under the water-wind alternate erosion increased by 2.7%-18.9% , and coarse particles (> 0.05 mm) decreased by 3.7%-9.3%. However, the changing trend of erosive sediment particles after the wind erosion at wind speeds of 11 and 14 m x s(-1) was different along with the rainfall intensity and duration. The erosive sediment particles at the rainfall intensities of 60, 80, 100 mm x h(-1) changed to greater extents than at the 150 mm x h(-1) rainfall intensity with longer than 15 min runoff flowing. PMID:24830236

  9. Macrophytes in shallow lakes: relationships with water, sediment and watershed characteristics.

    PubMed

    Kissoon, La Toya T; Jacob, Donna L; Hanson, Mark A; Herwig, Brian R; Bowe, Shane E; Otte, Marinus L

    2013-08-01

    We examined macrophyte-environment relationships in shallow lakes located within the Prairie Parkland and Laurentian Mixed Forest provinces of Minnesota. Environmental variables included land cover within lake watersheds, and within-lake, water and sediment characteristics. CCA indicated that sediment fraction smaller than 63 ?m (f<63), open water area, turbidity, and percent woodland and agricultural cover in watersheds were significant environmental variables explaining 36.6% of variation in macrophyte cover. When Province was added to the analysis as a spatial covariate, these environmental variables explained 30.8% of the variation in macrophyte cover. CCA also indicated that pH, f<63, percent woodland cover in watersheds, open water area, emergent vegetation area, and organic matter content were significant environmental variables explaining 43.5% of the variation in macrophyte biomass. When Province was added to the analysis as a spatial covariate, these environmental variables explained 39.1% of the variation in macrophyte biomass. The f<63 was the most important environmental variable explaining variation for both measures of macrophyte abundance (cover and biomass) when Province was added as a spatial covariate to the models. Percent woodland in watersheds, turbidity, open water area, and Ca+Mg explained 34.5% of the variation in macrophyte community composition. Most species showed a negative relationship with turbidity and open water area except for Potamogeton richardsonii, Stuckenia pectinata, and filamentous algae. Our study further demonstrates the extent to which macrophyte abundance and community composition are related to site- and watershed-scale variables including lake morphology, water and sediment characteristics, and percent land cover of adjacent uplands. PMID:23997402

  10. Kinetics of physiological skin flora in a suction blister wound model on healthy subjects after treatment with water-filtered infrared-A radiation.

    PubMed

    Daeschlein, G; Alborova, J; Patzelt, A; Kramer, A; Lademann, J

    2012-01-01

    The effect of water-filtered infrared-A radiation (wIRA) on normal skin flora was investigated by generating experimental wounds on the forearms of volunteers utilizing the suction blister technique. Over 7 days, recolonization was monitored parallel to wound healing. Four groups of treatment were compared: no therapy (A), dexpanthenol cream once daily (B), 20 min wIRA irradiation at 30 cm distance (C), and wIRA irradiation for 30 min once daily together with dexpanthenol cream once daily (D). All treatments strongly inhibited the recolonization of the wounds. Whereas dexpanthenol completely suppressed recolonization over the test period, recolonization after wIRA without (C) and in combination with dexpanthenol (D) was suppressed, but started on day 5 with considerably higher amounts after the combination treatment (D). Whereas the consequence without treatment (A) was an increasing amount of physiological skin flora including coagulase-negative staphylococci, all treatments (B-D) led to a reduction in physiological skin flora, including coagulase-negative staphylococci. In healthy volunteers, wIRA alone and in combination with dexpanthenol strongly inhibited bacterial recolonization with physiological skin flora after artificial wound setting using a suction-blister wound model. This could support the beneficial effects of wIRA in the promotion of wound healing. PMID:22123525

  11. Stress induced by hooking, net towing, elevated sea water temperature and air in sablefish: Lack of concordance between mortality and physiological measures of stress

    USGS Publications Warehouse

    Davis, M.W.; Olla, B.L.; Schreck, C.B.

    2001-01-01

    In a series of laboratory studies designed to simulate bycatch processes, sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium concentrations. In fish that were towed in a net and exposed to air, cortisol, lactate, potassium and sodium concentrations increased, but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air, that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood.

  12. Growth characteristics of aquatic macrophytes cultured in nutrient-enriched water: I. Water hyacinth, water lettuce, and pennywort

    Microsoft Academic Search

    K. R. Reddy; W. F. Debusk

    1984-01-01

    Seasonal growth characteristics and biomass yield potential of 3 floating aquatic macrophytes cultured in nutrient nonlimiting\\u000a conditions were evaluated in central Florida’s climatic conditions. Growth cycle (growth curve) of the plants was found to\\u000a be complete when maximum plant density was reached and no additional increase in growth was recorded. Biomass yield per unit\\u000a area and time was found to

  13. Are flowers physiological sinks or faucets? Costs and correlates of water use by flowers of Polemonium viscosum

    Microsoft Academic Search

    Candace Galen; Rabecca A. Sherry; Amy B. Carroll

    1999-01-01

    Water loss through inflorescences may place extreme demands on plant water status in arid environments. Here we examine how\\u000a corolla size, a trait known to influence pollination success, affects the water cost of flowering in the alpine skypilot, Polemonium viscosum. In a potometry experiment, water uptake rates of inflorescences were monitored during bud expansion and anthesis. Corolla\\u000a volume of fully

  14. Residues and Characteristics of Organochlorine Pesticides in the Surface Water in the Suburb of Beijing

    NASA Astrophysics Data System (ADS)

    CHEN, Jiawei; LIU, Chen; YANG, Zhongfang; WANG, Jiyuan

    Organochlorine Pesticides (OCPs), such as DDT and HCH, have stable chemical properties and less biodegradability. As a kind of persistent organic pollutants, they have high risk to the environment and human health. Although DDT and HCH have been prohibited in China since 1983, they are still found in some soil and water nowadays. Water resource is very important in natural environment and essential for agriculture. The existence of OCPs in some surface water in Beijing has been detected with different levels according to previous investigations. In recent years, many measures have been taken to control the pollution and to monitor the environment, and more attention has been paid to the status of surface water today. In this study, the water samples were collected from the Wenyu, Beiyun, Yanqing, Fangshan, Changping, and Shunyi Rivers in the suburb of Beijing, and the residues and characteristics of DDT and HCH were studied. The results showed that the contents of DDTs and HCHs were ND-13.98 ng/L and 3.87-146.42 ng/L, respectively. According to the indicators of the ratio values of (DDD+DDE)/DDT and ?-HCH/?-HCH, the source of pollution and its potential risk are also discussed in this article.

  15. Developmental Physiology

    NSDL National Science Digital Library

    This Web portal offered through the University of North Texas aims to "promote a sense of identity and connectivity among interested scientists and students active in the burgeoning field of developmental physiology." Users will find a wide array of useful features and services, including developmental physiology news, career and funding information, regularly updated links to related publications, a searchable database of developmental physiology researchers worldwide, op-ed pieces, hundreds of related links, and more. A helpful intra-site search engine has been recently added.

  16. Dynamic Model Investigation of the Rough-Water Landing Characteristics of a Spacecraft

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Dynamic Model Investigation of the Rough-Water Landing Characteristics of a Spacecraft. The investigation was made to study the rough-water landing characteristics of a Gemini type of spacecraft. The investigations were made with a 1/6-scale dynamic model in a simulated sea state 4 rough water. Parachute letdown landings were simulated with the model at various yaw angles and horizontal velocities. The vertical velocity and landing attitude remained constant. The range of maximum lateral and longitudinal acceleration was from about 3-1/2g to 16g while that for the maximum normal acceleration was from lg to 15g. The range of maximum angular acceleration was from about 0 to 190 radians per second(exp 2). The smoothest behavior and the lowest angular acceleration occurred at the 90 degree yaw angle. The normal acceleration was near minimum at this condition. [Entire movie available on DVD from CASI as Doc ID 20070031004. Contact help@sti.nasa.gov

  17. Sociodemographic Characteristics and Beverage Intake of Children Who Drink Tap Water

    PubMed Central

    Patel, Anisha I.; Shapiro, Daniel J.; Wang, Y. Claire; Cabana, Michael D.

    2015-01-01

    Background Tap water provides a calorie-free, no-cost, environmentally friendly beverage option, yet only some youth drink it. Purpose To examine sociodemographic characteristics, weight status, and beverage intake of those aged 1–19 years who drink tap water. Methods National Health and Nutrition Examination Survey data (2005–2010) were used to examine factors associated with tap water consumption. A comparison was made of beverage intake among tap water consumers and nonconsumers, by age, race/ethnicity, and income. Results Tap water consumption was more prevalent among school-aged children (OR=1.85, 95% CI=1.47, 2.33, for those aged 6–11 years; OR=1.85, 95% CI=1.32, 2.59, for those aged 12–19 years) as compared to those aged 1–2 years. Tap water intake was less prevalent among girls/women (OR=0.76, 95% CI=0.64, 0.89); Mexican Americans (OR=0.32, 95% CI=0.23, 0.45); non-Hispanic blacks (OR=0.48, 95% CI=0.34, 0.67); and others (OR=0.50, 95% CI=0.36, 0.68) as compared to whites; Spanish speakers (OR=0.72, 95% CI=0.55, 0.95); and among referents with a lower than Grade-9 education (OR=0.52, 95% CI=0.31, 0.88); Grade 9–11 education (OR=0.50, 95% CI=0.32, 0.77); and high school/General Educational Development test completion (OR=0.50, 95% CI=0.33, 0.76), as compared to college graduates. Tap water consumers drank more fluid (52.5 vs 48.0 ounces, p<0.01); more plain water (20.1 vs 15.2 ounces, p<0.01); and less juice (3.6 vs 5.2 ounces, p<0.01) than nonconsumers. Conclusions One in six children/adolescents does not drink tap water, and this finding is more pronounced among minorities. Sociodemographic disparities in tap water consumption may contribute to disparities in health outcomes. Improvements in drinking water infrastructure and culturally relevant promotion may help to address these issues. PMID:23790991

  18. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    NASA Astrophysics Data System (ADS)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  19. Effects of the water extract of Gynura bicolor (Roxb. & Willd.) DC on physiological and immune responses to Vibrio alginolyticus infection in white shrimp (Litopenaeus vannamei).

    PubMed

    Hsieh, Shu-Ling; Wu, Chih-Chung; Liu, Chun-Hung; Lian, Juang-Lin

    2013-07-01

    Gynura bicolor (Roxb. & Willd.) DC is widely distributed in certain areas of Asia and is very popular in vegetarian cuisine in Taiwan. To investigate the regulatory roles of G. bicolor in various functions in crustaceans, we examined innate non-specific immune responses (including total hemocyte count (THC), phenoloxidase activity (PO), respiratory bursts (RBs), and superoxide dismutase (SOD) activity), physiological responses (including haemolymph glucose, lactate, and lipids), and gene expressions (including prophenoloxidase (proPO), lipopolysaccharide- and b-1,3-glucan-binding protein (LGBP), and peroxinectin (PE) mRNA transcripts) to the pathogen Vibrio alginolyticus in white shrimp (Litopenaeus vannamei) that were individually injected with the water extract from G. bicolor at 2, 4, and 8 ?g g(-1). Results indicated that PO, RBs, SOD activity, proPO, LGBP, and PE mRNA transcripts of shrimps receiving the water extract of G. bicolor at 2, 4, and 8 ?g g(-1) significantly increased after challenge with V. alginolyticus for 96 h. However, no significant difference in the THC was seen at any dose. L. vannamei injected with the water extract of G. bicolor at all doses respectively maintained lower glucose, lactate, and lipid levels in response to V. alginolyticus challenge at 12-36, 24-36, and 24-48 h. Survival rates at 24-72 h of L. vannamei that received G. bicolor at any dose was significantly higher than those of shrimp that received saline. It was concluded that the water extract of G. bicolor can maintain physiological homeostasis and enhance immunity against V. alginolyticus infection in L. vannamei. PMID:23603309

  20. Validation of national land-cover characteristics data for regional water-quality assessment

    USGS Publications Warehouse

    Zelt, R.B.; Brown, J.F.; Kelley, M.S.

    1995-01-01

    Land-cover information is used routinely to support the interpretation of water-quality data. The Prototype 1990 Conterminous US Land Cover Characteristics Data Set, developed primarily from Advanced Very High Resolution Radiometer (AVHRR) data, was made available to the US Geological Survey's National Water-Quality Assessment (NAWQA) Program. The study described in this paper explored the utility of the 1990 national data set for developing quantitative estimates of the areal extent of principal land-cover types within large areal units. Land-cover data were collected in 1993 at 210 sites in the Central Nebraska Basins, one of the NAWQA study units. Median percentage-corn estimates for each sampling stratum wre used to produce areally weighted estimates of the percentage-corn cover for hydrologic units. Comparison of those areal estimates with an independent source of 1992 land-cover data showed good agreement. -Authors

  1. Conceptual design and thermal-hydraulic characteristics of natural circulation Boiling Water Reactors

    SciTech Connect

    Kataoka, Y.; Suzuki, H.; Murase, M. (Energy Research Lab., Hitachi, Ltd., Moriyama-cho, Hitachi-shi 316 (JP)); Horiuchi, T.; Miki, M. (Hitachi Works, Hitachi Ltd., Saiwai-cho, Hitachi-shi 317 (JP))

    1988-08-01

    A natural circulation boiling water reactor (BWR) with a rated capacity of 600 MW (electric) has been conceptually designed for small- and medium-sized light water reactors. The components and systems in the reactor are simplified by eliminating pumped recirculation systems and pumped emergency core cooling systems. Consequently, the volume of the reactor building is -- 50% of that for current BWRs with the same rated capacity; the construction period is also shorter. Its thermal-hydraulic characteristics, critical power ratio (CPR) and flow stability at steady state, decrease in the minimum CPR (..delta..MCPR) at transients, and the two-phase mixture level in the reactor pressure vessel (RPV) during accidents are investigated. The two-phase mixture level in the RPV during an accident does not decrease to lower than the top of the core; the core uncovery and heatup of fuel cladding would not occur during any loss-of-coolant accident.

  2. Physiological Stress of High NH 4 + Concentration in Water Column on the Submersed Macrophyte Vallisneria Natans L

    Microsoft Academic Search

    Te Cao; Ping Xie; Zhongqiang Li; Leyi Ni; Meng Zhang; Jun Xu

    2009-01-01

    The submersed macrophyte, Vallisneria natans L., was cultured in laboratory with NH4+-enriched tap water (1 mg L?1 NH4-N) for 2 months and the stressful effects of high ammonium (NH4+) concentrations in the water column on this species was evaluated. The plant growth was severely inhibited by the NH4+ supplement in the water column. The plant carbon and nitrogen metabolisms were disturbed by the NH4+

  3. Development of study on the dynamic characteristics of deep water mooring system

    NASA Astrophysics Data System (ADS)

    Tang, You-Gang; Zhang, Su-Xia; Zhang, Ruo-Yu; Liu, Hai-Xiao

    2007-09-01

    To meet the needs of those exploiting deepwater resources, TLP and SPAR platforms are used in some areas and are considered excellent platforms in deep water. However, many problems remain to be resolved. The design of mooring systems is a key issue for deep water platforms. Environmental loads in deep water effect the physical characteristics of mooring line materials. The configuration and analysis of mooring systems involve nonlinearity due to this fluid-solid coupling, nonlinear hydrodynamic forces, and their effects on stability of motion. In this paper, some pivotal theories and technical questions are presented, including modeling of mooring lines, the theory and method of coupled dynamics analysis on the mooring system, and the development of methodologies for the study of nonlinear dynamics of mooring systems. Further study on mooring systems in deep water are recommended based on current knowledge, particularly dynamic parameters of different materials and cable configuration, interactions between seabed and cable, mechanisms of mooring system response induced by taut/slack mooring cables, discontinuous stiffness due to system materials, mooring construction, and motion instability, etc.

  4. Adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon.

    PubMed

    Nam, Seung-Woo; Choi, Dae-Jin; Kim, Seung-Kyu; Her, Namguk; Zoh, Kyung-Duk

    2014-04-15

    In this study, we investigated adsorption characteristics of nine selected micropollutants (six pharmaceuticals, two pesticides, and one endocrine disruptor) in water using an activated carbon. The effects of carbon dosage, contact time, pH, DOM (dissolved organic matter), and temperature on the adsorption removal of micropollutants were examined. Increasing carbon dosage and contact time enhanced the removal of micropollutants. Sorption coefficients of hydrophilic compounds (caffeine, acetaminophen, sulfamethoxazole, and sulfamethazine) fit a linear isotherm and hydrophobic compounds (naproxen, diclofenac, 2, 4-D, triclocarban, and atrazine) fit a Freundlich isotherm. The removal of hydrophobic pollutants and caffeine were independent of pH changes, but acetaminophen, sulfamethazine, and sulfamethoxazole were adsorbed by mainly electrostatic interaction with activated carbon and so were affected by pH. The decrease in adsorption removal in surface water samples was observed and this decrease was more significant for hydrophobic than hydrophilic compounds. The decline in the adsorption capacity in surface water samples is caused by the competitive inhibition of DOM with micropollutants onto activated carbon. Low temperature (5°C) also decreased the adsorption removal of micropollutants, and affected hydrophobic compounds more than hydrophilic compounds. The results obtained in this study can be applied to optimize the adsorption capacities of micropollutants using activated carbon in water treatment process. PMID:24572271

  5. Electric discharge in the water: physics of formation and radiative characteristics.

    NASA Astrophysics Data System (ADS)

    Anpilov, Andrei; Barkhudarov, Eduard; Kozlov, Yurii; Kossyi, Igor; Silakov, Valerii; Temchin, Savelii

    2004-09-01

    ELECTRIC DISCHARGE IN THE WATER: PHYSICS OF FORMATION AND RADIATIVE CHARACTERISTICS 2.10. Lighting plasmas. 2.26. Other plasma topics. A.M.Anpilov, E.M.Barkhudarov, Yu.N.Kozlov, I.A.Kossyi, V.P.Silakov and S.M.Temchin Two types of electric discharge in the water have been investigated: discharge between two electrodes and multielectrode gliding surface discharge. Results are presented from experimental studies of the prebreakdown phase of an electric discharge between the point (anode) and plane (cathode) electrodes immersed in the water with different initial conductivity. When a high-voltage pulse is applied, the induced conductivity is detected in the discharge gap. Its value is one order of magnitude higher than the initial one. It is shown that the induced conductivity increases almost linearly with initial conductivity. The induced conductivity correlates with the UV emission from the cathode surface. A qualitative analysis of the experimental results is performed. Investigations of a spectrum of radiation of discharge in water have been carried out. On the base of broadening and shifting of atomic hydrogen and oxygen lines electron density in a prebreakdown as well as breakdown stages has been determined. Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190 £l£430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the gliding surface discharge in water for its disinfection is analysed.

  6. Membrane filtration characteristics in membrane-coupled activated sludge system — the effect of physiological states of activated sludge on membrane fouling

    Microsoft Academic Search

    In-Soung Chang; Chung-Hak Lee

    1998-01-01

    The effect of sludge physiology on membrane fouling was investigated in a membrane-coupled activated sludge (MCAS) system. A series of ultrafiltrations were performed to assess the flux behaviors according to foaming potential, solids retention time (SRT), growth phase and nutrient condition of the activated sludge. The foaming sludge showed greater flux decline than the non-foaming sludge. The extraordinary increase, that

  7. [Characteristics of water soluble inorganic ions in fine particles emitted from coal-fired power plants].

    PubMed

    Duan, Lei; Ma, Zi-Zhen; Li, Zhen; Jiang, Jing-Kun; Ye, Zhi-Xiang

    2015-03-01

    Currently, China suffers from serious pollution of fine particulate matter (PM2.5). Coal-fired power plant is one of the most important sources of PM2.5 in the atmosphere. To achieve the national goals of total emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NO(x)) during the 11th and 12th Five-Year Plan, most of coal-fired power plants in China have installed or will install flue gas desulfurization (FGD) and flue gas denitrification (DNO(x)) systems. As a result, the secondary PM2.5, generated from gaseous pollutants in the atmosphere, would be decreased. However, the physical and chemical characteristics of PM2.5 in flue gas would be affected, and the emission of primary PM2.5 might be increased. This paper summarized the size distributions of PM2.5 and its water soluble ions emitted from coal-fired power plants, and highlighted the effects of FGD and DNO(x) on PM2.5 emission, especially on water soluble ions (such as SO4(2-), Ca2+ and NH4+) in PM2.5. Under the current condition of serious PM2.5 pollution and wide application of FGD and DNO(x), quantitative study on the effects of FGD and DNO(x) installation on emission characteristics of PM2.5 from coal-fired power plants is of great necessity. PMID:25929084

  8. Integrated Transcriptomic and Proteomic Analysis of the Physiological Response of Escherichia coli O157:H7 Sakai to Steady-state Conditions of Cold and Water Activity Stress*

    PubMed Central

    Kocharunchitt, Chawalit; King, Thea; Gobius, Kari; Bowman, John P.; Ross, Tom

    2012-01-01

    An integrated transcriptomic and proteomic analysis was undertaken to determine the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air. The response of E. coli during exponential growth at 25 °C aw 0.985, 14 °C aw 0.985, 25 °C aw 0.967, and 14 °C aw 0.967 was compared with that of a reference culture (35 °C aw 0.993). Gene and protein expression profiles of E. coli were more strongly affected by low water activity (aw 0.967) than by low temperature (14 °C). Predefined group enrichment analysis revealed that a universal response of E. coli to all test conditions included activation of the master stress response regulator RpoS and the Rcs phosphorelay system involved in the biosynthesis of the exopolysaccharide colanic acid, as well as down-regulation of elements involved in chemotaxis and motility. However, colanic acid-deficient mutants were shown to achieve comparable growth rates to their wild-type parents under all conditions, indicating that colanic acid is not required for growth. In contrast to the transcriptomic data, the proteomic data revealed that several processes involved in protein synthesis were down-regulated in overall expression at 14 °C aw 0.985, 25 °C aw 0.967, and 14 °C aw 0.967. This result suggests that during growth under these conditions, E. coli, although able to transcribe the required mRNA, may lack the cellular resources required for translation. Elucidating the global adaptive response of E. coli O157:H7 during exposure to chilling and water activity stress has provided a baseline of knowledge of the physiology of this pathogen. PMID:22008207

  9. Influence of selected water quality characteristics on the toxicity of lambda-cyhalothrin and gamma-cyhalothrin to Hyalella azteca

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to assess the influence of suspended solids, dissolved organic carbon, and phytoplankton (as chlorophyll a) water quality characteristics on lambda-cyhalothrin and gamma-cyhalothrin aqueous toxicity to Hyalella azteca using natural water from 12 ponds and lakes in Mississipp...

  10. Field-Obtained Soil Water Characteristic Curves and Hydraulic Conductivity Functions

    NASA Astrophysics Data System (ADS)

    Elvis, Ishimwe

    A compacted clay liner (test pad) was constructed and instrumented with volumetric water content and soil matric potential sensors to determine soil water characteristic curves (SWCC) and hydraulic conductivity (k) functions. Specifically, the compacted clay liner was subjected to an infiltration cycle during a sealed double ring infiltrometer (SDRI) test followed by a drying cycle. After the drying cycle, Shelby tube samples were collected from the compacted clay liner and flexible wall permeability (FWP) tests were conducted on sub-samples to determine the saturated hydraulic conductivity. Moreover, two computer programs (RETC and UNSAT-H) were utilized to model the SWCCs and k-functions of the soil based on obtained measurements including the volumetric water content, the soil matric potential, and the saturated hudraulic conductivity (ks). Results obtained from the RETC program (s, r, ?, n and ks) were ingested into UNSAT-H program to calculate the movement of water (rate and location) through the compacted clay liner. Although a linear wetting front (location of water infiltration as a function of time) is typically utilized for SDRI calculations, the use of a hyperbolic wetting front is recommended as a hyperbolic wetting front was modeled from the testing results. The suggested shape of the wetting front is associated with utilization of the desorption SWCC instead of the sorption SWCC and with relatively high values of ks (average value of 7.2E-7 cm/sec) were measured in the FWP tests while relatively low values of ks (average value of 1.2E-7 cm/sec) were measured in the SDRI test.

  11. Wear of nano-TiO2/UHMWPE composites radiated by gamma ray under physiological saline water lubrication.

    PubMed

    Xiong, Dangsheng; Lin, Jianming; Fan, Dongli; Jin, Zhongmin

    2007-11-01

    Nano-TiO(2)/UHMWPE composites were prepared by hot press procedure, and then radiated by gamma ray in dose of 120 kGy, 250 kGy and 500 kGy. The hardness of the composites was initially determined. Subsequently the wear against a CoCrMo alloy counterface were tested in a knee simulator under physiological saline lubrication. The morphologies of the worn surfaces were examined with optical microscope. The structure of the samples was determined by IR and XRD. The results showed that the wear rate of the composite UHMWPE decreased when filled with proper amount of nano-TiO(2) and with the radiation dose. PMID:17665107

  12. Prediction of micro-bubble dissolution characteristics in water and seawater

    SciTech Connect

    Kawahara, Akimaro; Sadatomi, Michio; Matsuura, Hidetoshi; Tominaga, Mayo; Noguchi, Masanori [Department of Mechanical System Engineering, Kumamoto University, Kurokami 2-39-1, Kumamoto City 860-8555 (Japan); Matsuyama, Fuminori [Department of Mechanical Engineering, Sasebo National College of Technology (Japan)

    2009-07-15

    This paper is concerned with the prediction of micro-bubble dissolution characteristics in water and seawater when microbubbles are generated by a Sadatomi-type micro-bubble generator (2003) with a spherical body in a flowing liquid tube. In the experiments, in order to know the effects of the salinity on the characteristics, tap water and an artificial seawater with different salt concentrations of 1 and 3 wt% were used as the test liquids. Parameters measured were the Sauter mean diameter of bubbles, d{sub BS}, the void fraction, {alpha}, the rising velocity of bubbles, u{sub G}, the interfacial area concentration, a, the volumetric mass transfer coefficient, K{sub L}a, and the liquid-side mass transfer coefficient, K{sub L}. In the analysis, for predicting {alpha}, K{sub L}a and K{sub L}, some correlations in the literatures were tested against the present data. Furthermore, in order to improve the predictability, new correlations were developed based on the present data. The prediction of K{sub L}a with the new correlation agreed well with Nishino et al.'s [T. Nishino, K. Terasaka, M. Ishida, Application for several micro-bubble generators for gas absorber, in: Proceedings of the Annual Meeting of the Japanese Society for Multiphase Flow, 2006, pp. 276-277 (in Japanese)] and Li and Tsuge's [P. Li, H. Tsuge, Water treatment by induced air flotation using microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 896-903; P. Li, H. Tsuge, Ozone transfer in a new gas-induced contactor with microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 1213-1220] data for different aeration systems using several different micro-bubble generators. (author)

  13. Laminar heat transfer and friction factor characteristics of carbon nano tube/water nanofluids.

    PubMed

    Rathnakumar, P; Mayilsamy, K; Suresh, S; Murugesan, P

    2014-03-01

    This paper presents an experimental investigation on the convective heat transfer and friction factor characteristics of CNT/water nanofluid through a circular tube fitted with helical screw tape inserts with constant heat flux under laminar flow condition. Nanofluids of 0.1% and 0.2% volume fractions are prepared by two step method. Thermo-physical properties like thermal conductivity and viscosity are measured by using KD2 thermal property analyzer and Brooke field cone and plate viscometer respectively. From the measurements, it is found that the viscosity increase is substantially higher than the increase in the thermal conductivity. The helical screw tape insets with twist ratios Y = 3, 2.44 and 1.78 are used to study the convective heat transfer and friction factor characteristics under laminar flow in the Reynolds number range of 520-2500. It is observed that, in a plain tube, maximum enhancement in Nusselt number for 0.1% and 0.2% volume fractions of nanofluids compared to pure water is 15% and 32% respectively. With the use of inserts, maximum enhancement in Nusselt number corresponding to twist ratios of 1.78, 2.44 and 3 are obtained as 8%, 16% and 4.6% for 0.1% volume fraction of nanofluid and 5%, 4% and 12% for 0.2% volume fraction of nanofluid when compared with water in plain tube. Thermal performance factor evaluation revealed that the values at all Reynolds number for all twist ratios and both concentration of CNT nanofluid are greater than unity which indicates that helical screw tape inserts with twist ratios considered are feasible in terms of energy saving in laminar flow. PMID:24745238

  14. Regulatory Physiology

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Whitson, Peggy A.; Putcha, Lakshmi; Baker, Ellen; Smith, Scott M.; Stewart, Karen; Gretebeck, Randall; Nimmagudda, R. R.; Schoeller, Dale A.; Davis-Street, Janis

    1999-01-01

    As noted elsewhere in this report, a central goal of the Extended Duration Orbiter Medical Project (EDOMP) was to ensure that cardiovascular and muscle function were adequate to perform an emergency egress after 16 days of spaceflight. The goals of the Regulatory Physiology component of the EDOMP were to identify and subsequently ameliorate those biochemical and nutritional factors that deplete physiological reserves or increase risk for disease, and to facilitate the development of effective muscle, exercise, and cardiovascular countermeasures. The component investigations designed to meet these goals focused on biochemical and physiological aspects of nutrition and metabolism, the risk of renal (kidney) stone formation, gastrointestinal function, and sleep in space. Investigations involved both ground-based protocols to validate proposed methods and flight studies to test those methods. Two hardware tests were also completed.

  15. Differential growth, physiological and biochemical responses of niger ( Guizotia abyssinica Cass.) cultivars to water-deficit (drought) stress

    Microsoft Academic Search

    S. G. Ghane; V. H. Lokhande; T. D. Nikam

    The present study demonstrates the effect of polyethylene glycol-8000 (PEG) and percent field capacity (FC%)-induced water-deficit\\u000a stress on growth, water status, productivity and various biochemical parameters in Guizotia abyssinica Cass. cultivars (IGP 76, GA 10, No. 71 and IGPN 2004) at seedling and maturity stages of the plant. Cultivar GA 10 showed\\u000a higher, IGP 76 and No. 71 moderate, and

  16. Characteristics of ac capillary discharge produced in electrically conductive water solution

    NASA Astrophysics Data System (ADS)

    DeBaerdemaeker, F.; Simek, M.; Schmidt, J.; Leys, C.

    2007-05-01

    Basic electrical, optical and calorimetric characteristics of an ac (50 Hz) driven capillary discharge produced in a water solution were studied for initial water solution conductivity in the range 50-1000 µS cm-1. Typical current and voltage waveforms and emission intensities produced by several electronically excited species were recorded with high time resolution. The evolution of the electrical current, power and capillary resistance was inspected during positive ac half-cycle for various operational regimes. A fast relaxation of the discharge following a breakdown event was observed. Optical measurements indicate that radiative species are mostly generated during the first few hundreds of nanoseconds of plasma generation and that the average duration of plasma emission induced by a discharge pulse is of the order of a few microseconds. Results of calorimetric measurements are in good agreement with average electrical measurements and support the assumption that the discharge is a constant source of heat delivered to the liquid. Assuming that only a fraction of the heat released inside the capillary can be transported by conduction through the capillary wall and via its orifices, the processes of bubble formation, expulsion and re-filling the capillary with 'fresh' water must play a key role in maintaining a thermal balance during long-time steady-state operation of the device. Furthermore, a simplified numerical model and a first order energy deposition calculation prove the plausibility of the bubble breakdown mechanism.

  17. Spatial and seasonal characteristics of river water chemistry in the Taizi River in Northeast China.

    PubMed

    Bu, Hongmei; Meng, Wei; Zhang, Yuan

    2014-06-01

    Anthropogenic activities have led to water quality deterioration in many parts of the world, especially in Northeast China. The current work investigated the spatiotemporal variations of water quality in the Taizi River by multivariate statistical analysis of data from the 67 sampling sites in the mainstream and major tributaries of the river during dry and rainy seasons. One-way analysis of variance indicated that the 20 measured variables (except pH, 5-day biological oxygen demand, permanganate index, and chloride, orthophosphate, and total phosphorus concentrations) showed significant seasonal (p ? 0.05) and spatial (p < 0.05) variations among the mainstream and major tributaries of the river. Hierarchical cluster analysis of data from the different seasons classified the mainstream and tributaries of the river into three clusters, namely, less, moderately, and highly polluted clusters. Factor analysis extracted five factors from data in the different seasons, which accounted for the high percentage of the total variance and reflected the integrated characteristics of water chemistry, organic pollution, phosphorous pollution, denitrification effect, and nitrogen pollution. The results indicate that river pollution in Northeast China was mainly from natural and/or anthropogenic sources, e.g., rainfall, domestic wastewater, agricultural runoff, and industrial discharge. PMID:24477615

  18. Streamflow and Water-Quality Characteristics for Wind Cave National Park, South Dakota, 2002-03

    USGS Publications Warehouse

    Heakin, Allen J.

    2004-01-01

    A 2-year study of streamflow and water-quality characteristics in Wind Cave National Park was performed by the U.S. Geological Survey in cooperation with the National Park Service. During this study, streamflow and water-quality data were collected for three of the park's perennial streams (Cold Spring, Beaver, and Highland Creeks) from January 2002 through November 2003. The potential influence of parking lot runoff on cave drip within Wind Cave also was investigated by collecting and analyzing several time-dependent samples from a drainage culvert downstream from the parking lot and from Upper Minnehaha Falls inside the cave following a series of simulated runoff events. The primary focus of the report is on data collected during the 2-year study from January 2002 to November 2003; however, data collected previously also are summarized. Losing reaches occur on both Beaver and Highland Creeks as these streams flow across outcrops of bedrock aquifers within the park. No streamflow losses occur along Cold Spring Creek because its confluence with Beaver Creek is located upstream from the outcrop of the Madison aquifer, where most streamflow losses occur. Physical properties, major ions, trace elements, nutrients, bacteria, benthic macroinvertebrates, organic (wastewater) compounds, bottom sediment, and suspended sediment are summarized for samples collected from 2 sites on Cold Spring Creek, 2 sites on Beaver Creek, and 1 site on Highland Creek. None of the constituent concentrations for any of the samples collected during 2002-03 exceeded any of the U.S. Environmental Protection Agency drinking-water standards, with the exception of the Secondary Maximum Contaminant Level for pH, which was exceeded in numerous samples from Beaver Creek and Highland Creek. Additionally, the pH values in several of these same samples also exceeded beneficial-use criteria for coldwater permanent fisheries and coldwater marginal fisheries. Water temperature exceeded the coldwater permanent fisheries criterion in numerous samples from all three streams. Two samples from Highland Creek also exceeded the coldwater marginal fisheries criterion for water temperature. Mean concentrations of ammonia, orthophosphate, and phosphorous were higher for the upstream site on Beaver Creek than for other water-quality sampling sites. Concentrations of E. coli, fecal coliform, and total coliform bacteria also were higher at the upstream site on Beaver Creek than for any other site. Samples for the analysis of benthic macroinvertebrates were collected from one site on each of the three streams during July 2002 and May 2003. The benthic macroinvertebrate data showed that Beaver Creek had lower species diversity and a higher percentage of tolerant species than the other two streams during 2002, but just the opposite was found during 2003. However, examination of the complete data set indicates that the quality of water at the upstream site was generally poorer than the quality of water at the downstream site. Furthermore, the quality of water at the upstream site on Beaver Creek is somewhat degraded when compared to the quality of water from Highland and Cold Spring Creeks, indicating that anthropogenic activities outside the park probably are affecting the quality of water in Beaver Creek. Samples for the analysis of wastewater compounds were collected at least twice from four of the five water-quality sampling sites. Bromoform, phenol, caffeine, and cholesterol were detected in samples from Cold Spring Creek, but only phenol was detected at concentrations greater than the minimum reporting level. Concentrations of several wastewater compounds were estimated in samples collected from sites on Beaver Creek, including phenol, para-cresol, and para-nonylphenol-total. Phenol was detected at both sites on Beaver Creek at concentrations greater than the minimum reporting level. Bromoform; para-cresol; ethanol,2-butoxy-phosphate; and cholesterol were detected

  19. Effects of a 6-month exercise program pilot study on walking economy, peak physiological characteristics, and walking performance in patients with peripheral arterial disease

    PubMed Central

    Crowther, Robert G; Leicht, Anthony S; Spinks, Warwick L; Sangla, Kunwarjit; Quigley, Frank; Golledge, Jonathan

    2012-01-01

    The purpose of this study was to examine the effects of a 6-month exercise program on submaximal walking economy in individuals with peripheral arterial disease and intermittent claudication (PAD-IC). Participants (n = 16) were randomly allocated to either a control PAD-IC group (CPAD-IC, n = 6) which received standard medical therapy, or a treatment PAD-IC group (TPAD-IC; n = 10) which took part in a supervised exercise program. During a graded treadmill test, physiological responses, including oxygen consumption, were assessed to calculate walking economy during submaximal and maximal walking performance. Differences between groups at baseline and post-intervention were analyzed via Kruskal–Wallis tests. At baseline, CPAD-IC and TPAD-IC groups demonstrated similar walking performance and physiological responses. Postintervention, TPAD-IC patients demonstrated significantly lower oxygen consumption during the graded exercise test, and greater maximal walking performance compared to CPAD-IC. These preliminary results indicate that 6 months of regular exercise improves both submaximal walking economy and maximal walking performance, without significant changes in maximal walking economy. Enhanced walking economy may contribute to physiological efficiency, which in turn may improve walking performance as demonstrated by PAD-IC patients following regular exercise programs. PMID:22566743

  20. Fractal physiology

    Microsoft Academic Search

    William Deering; Bruce J. West

    1992-01-01

    The nature of fractals and the use of fractals instead of classical scaling concepts to describe the irregular surfaces, structures, and processes exhibited by physiological systems are described. The mathematical development of fractals is reviewed, and examples of natural fractals are cited. Relationships among power laws, noise, and fractal time signals are examined

  1. Survival and physiological responses of hatchling blanding's turtles (Emydoidea blandingii) to submergence in normoxic and hypoxic water under simulated winter conditions.

    PubMed

    Dinkelacker, Stephen A; Costanzo, Jon P; Iverson, John B; Lee, Richard E

    2005-01-01

    Overwintering habits of hatchling Blanding's turtles (Emydoidea blandingii) are unknown. To determine whether these turtles are able to survive winter in aquatic habitats, we submerged hatchlings in normoxic (155 mmHg Po2) and hypoxic (6 mmHg Po2) water at 4 degrees C, recording survival times and measuring changes in key physiological variables. For comparison, we simultaneously studied hatchling softshell (Apalone spinifera) and snapping (Chelydra serpentina) turtles, which are known to overwinter in aquatic habitats. In normoxic water, C. serpentina and A. spinifera survived to the termination of the experiment (76 and 77 d, respectively). Approximately one-third of the E. blandingii died during 75 d of normoxic submergence, but the cause of mortality was unclear. In hypoxic water, average survival times were 6 d for A. spinifera, 13 d for E. blandingii, and 19 d for C. serpentina. Mortality during hypoxic submergence was probably caused by metabolic acidosis, which resulted from accumulated lactate. Unlike the case with adult turtles, our hatchlings did not increase plasma calcium and magnesium, nor did they sequester lactate within the shell. Our results suggest that hatchling E. blandingii are not particularly well suited to hibernation in hypoxic aquatic habitats. PMID:15887082

  2. Effect of pH on the rheological and structural properties of gels of water-washed chicken-breast muscle at physiological ionic strength.

    PubMed

    Feng, Y; Hultin, H O

    2001-08-01

    Adjustment of pH from 6.4 to neutrality improved gelling ability and water-holding capacity of twice water-washed, minced chicken-breast muscle significantly at physiological ionic strength, at which the majority of the myofibrillar proteins, including myosin, are not soluble. A strain value of 2.2 was obtained at neutral pH. Myofibrils were the main components of the gel network at both pH 6.4 and 7.0; however, the myofibrillar distribution varied with the pH value. At pH 6.4, myofibrils formed a network of localized aggregates leaving large voids between, whereas at neutral pH, an evenly distributed network of myofibrils was formed. In addition, at neutral pH, a network of fine strands was found within the network of myofibrils. The network was much less developed at pH 6.4. The thin and thick filaments within each myofibrillar structure were disorganized at both pH values. The intramyofibrillar spaces were larger at neutral pH than at pH 6.4. It was proposed that adjustment of pH to neutrality increased electrostatic repulsion leading to a more even distribution of the myofibrillar proteins, a key factor responsible for the improved gel strength and water-holding capacity. PMID:11513691

  3. Sauna, shower, and ice water immersion. Physiological responses to brief exposures to heat, cool, and cold. Part III. Body temperatures.

    PubMed

    Kauppinen, K

    1989-04-01

    Nine active winter swimmer men were subjected to four exposures each imitating a form of hot or cold exposures or their combination practiced among the Finns: (A) sauna and head-out ice water immersion; (B) sauna and 15 degrees C shower; (C) sauna and room temperature; (D) head-out ice water immersion and room temperature. All exposures were repeated and ended with recovery at room temperature. Body core and surface temperatures were recorded. One surface probe was placed between the scapulae to detect any signs of thermogenic activity by brown adipose tissue upon cold exposures. In the sauna control of core temperature was lost at esophageal temperature Tes 38 degrees C where the mean skin temperature exceeded the Tes. The brief ice water immersions did not disturb the thermal balance of the body core. The interscapular surface temperature recording provided circumstantial evidence of functioning thermogenic tissue in the area. PMID:2736003

  4. Mercury levels in walleyes from Wisconsin lakes of different water and sediment chemistry characteristics

    SciTech Connect

    Lathrop, R.C.; Noonan, K.C.; Guenther, P.M.; Brasino, T.L.; Rasmussen, P.W.

    1989-01-01

    Forty-three lakes throughout Wisconsin were sampled in 1985-86 to determine the water and sediment chemistry characteristics that were associated with elevated concentrations of mercury in walleyes. Mean mercury concentrations for each of three different length classes of walleyes increased as the parameters lake pH, alkalinity, calcium, conductivity, or chlorophyll-a decreased. Low values for these parameters characterized most lakes in northern Wisconsin. Mean mercury concentrations exceeded the Wisconsin health standard of 0.5 micrograms (ug) Hg/g wet weight of fish for all walleye length classes in lakes with pH values < 6.0, for walleyes > or = to 15.0 inches in lakes with pH 6.0-6.9, and for walleyes > or = 20.0 in. in all lake pH categories. Apparently the older, larger walleyes in hard water as well as soft water lakes can accumulate enough mercury to warrant concern. Sediment mercury concentrations were generally < or = 0.02 ug/g dry weight for all study lakes, but sediment mercury and organic matter were higher in lakes with pH values < 7.0 than in lakes with pH > or = 7.0. Models were developed and tested to predict mercury concentrations in a 17-in. walleye for each lake. The best model derived from the study and tested on an independent dataset used alkalinity and calcium as independent variables. Clearly, walleyes from soft water, poorly buffered, low pH lakes have the highest concentrations of mercury, but the reasons for these higher concentrations require further study. 67 refs., 5 figs., 27 tabs.

  5. Sensitivity of limber pine (Pinus flexilis) seedling physiology to elevation, warming, and water availability across a timberline ecotone

    NASA Astrophysics Data System (ADS)

    Moyes, A. B.; Castanha, C.; Ferrenberg, S.; Germino, M. J.; Kueppers, L. M.

    2010-12-01

    Treelines occur where environmental gradients such as temperature become limiting to tree establishment, and are thus likely to respond to changes in climate. We collected gas exchange, water potential, and fluorescence measurements from limber pine (Pinus flexilis) seedlings planted into experimental plots at three elevations at Niwot Ridge, Colorado, ranging from within forest to alpine. At each site seeds from local high- and low-elevation populations were sewn into replicated and controlled watering and infrared heating treatment plots. Heating led to earlier snowmelt, germination, and soil moisture availability in spring; higher soil surface temperatures throughout the growing season; and drier soils in late summer. Assimilation rates in all plots were most strongly associated with soil moisture availability following germination, and decreased as soils dried over the growing season. Intrinsic water use efficiency was consistent for the two source populations, but there was evidence that individuals germinating from high-elevation seeds respired more per unit carbon assimilated under our experimental conditions. Chlorophyll fluorescence showed no evidence of photoinhibition in any elevation or treatment category. Earlier soil moisture depletion in heated plots was associated with lower midday stem water potentials and reduced stomatal conductance in August. Our watering treatments did not substantially reduce apparent midsummer water stress. Seedlings in ambient temperature plots had higher assimilation rates in August than those in heated plots, but also greater carbon loss via photorespiration. Moisture limitation in heated plots in summer interacted with variability in afternoon sun exposure within plots, and qualitative observations suggested that many seedlings were killed by desiccation and heat girdling at all elevations. While early snowmelt and moisture availability in heated plots provided a longer growing season, earlier reduction of soil moisture availability in summer offset this advantage for limber pine seedling carbon gain.

  6. The chemical/physical and microbiological characteristics of typical bath and laundry waste waters. [waste water reclamation during manned space flight

    NASA Technical Reports Server (NTRS)

    Hypes, W. D.; Batten, C. E.; Wilkins, J. R.

    1974-01-01

    Chemical/physical and microbiological characteristics are studied of typical bath and laundry waters collected during a 12 day test in which the untreated waste waters were reused for toilet flush. Most significant changes were found for ammonia, color, methylene blue active substances, phosphates, sodium, sulfates, total organic carbon, total solids, and turbidity in comparison with tap water baseline. The mean total number of microorganisms detected in the waste waters ranged from 1 million to 10 to the 7th power cells/m1 and the mean number of possible coliforms ranged from 10 to the 5th power to 1 million. An accumulation of particulates and an objectible odor were detected in the tankage used during the 12 day reuse of the untreated waste waters. The combined bath and laundry waste waters from a family of four provided 91 percent of the toilet flush water for the same family.

  7. Characteristics of water reuse and its effects on paddy irrigation system water balance and the riceland ecosystem

    Microsoft Academic Search

    Giveson Zulu; Masaru Toyota; Shin-ichi Misawa

    1996-01-01

    Rapid industrial development in the rice-growing regions has increased competition for the scarce water resources. Water reuse (surface and subsurface agriculture drainage water, storm runoff, sewerage effluent and industrial wastewater recycling) is in widespread use as a method of supplementing the paddy water supply, therefore, there is a need to clarify its effects on the paddy system water balance and

  8. A new cadmium reduction device for the microplate determination of nitrate in water, soil, plant tissue, and physiological fluids.

    PubMed

    Crutchfield, James D; Grove, John H

    2011-01-01

    A reusable catalytic reductor consisting of 96 copperized-cadmium pins attached to a microplate lid was developed to simultaneously reduce nitrate (NO3-) to nitrite (NO2-) in all wells of a standard microplate. The resulting NO2- is analyzed colorimetrically by the Griess reaction using a microplate reader. Nitrate data from groundwater samples analyzed using the new device correlated well with data obtained by ion chromatography (r2 = 0.9959). Soil and plant tissue samples previously analyzed for NO3- in an interlaboratory validation study sponsored by the Soil Science Society of America were also analyzed using the new technique. For the soil sample set, the data are shown to correlate well with the other methods used (r2 = 0.9976). Plant data correlated less well, especially for samples containing low concentrations of NO3-. Reasons for these discrepancies are discussed, and new techniques to increase the accuracy of the analysis are explored. In addition, a method is presented for analyzing NO3- in physiological fluids (blood serum and urine) after matrix modification with Somogyi's reagent. A protocol for statistical validation of data when analyzing samples with complex matrixes is also established. The simplicity, adaptability, and low cost of the device indicate its potential for widespread application. PMID:22320098

  9. Effect of Void Distribution Parameter and Axial Power Profile on Boiling Water Reactor Bifurcation Characteristics

    SciTech Connect

    Bragt, D.D.B. van [Delft University of Technology (Netherlands); Rizwan-uddin [University of Illinois (United States); Hagen, T.H.J.J. van der [Delft University of Technology (Netherlands)

    2000-02-15

    Bifurcation analyses of the impact of the void distribution parameter C{sub 0} and the axial power profile on the stability of boiling water reactors (BWRs) are reported. Bifurcation characteristics of heated channels (without nuclear feedback) appear to be very sensitive to the axial power profile. A turning point bifurcation was detected for a (symmetrically) peaked axial power profile. This kind of bifurcation does not occur for a uniformly heated channel.Both supercritical and subcritical Hopf bifurcations were encountered in a (nuclear-coupled) reactor system, depending on the strength of the void reactivity feedback. Subcritical bifurcations become less likely to occur as C{sub 0} is significantly larger than unity. In BWRs with a strong nuclear feedback, the oscillation amplitude of limit cycles caused by a supercritical bifurcation is very sensitive to both C{sub 0} and the axial power profile.

  10. Bimodal and multimodal descriptions of soil-water characteristic curves for structural soils.

    PubMed

    Liu, Shiyu; Yasufuku, Noriyuki; Liu, Qiang; Omine, Kiyoshi; Hemanta, Hazarika

    2013-01-01

    In the last decades several approaches have been developed to describe bimodal or multimodal soil-water characteristic curves (SWCCs). Unfortunately, most of these models were derived empirically. In the presented study, physically based bimodal and multimodal SWCC functions have been developed for structural soils. The model involved two or more continual pore series; the probability density functions for each pore series were assumed to be lognormal distribution and can be superposed to obtain the overall probability density function of the structural soils. The proposed functions were capable of simulating bimodal or multimodal SWCCs using parameters which can be related to physical properties of the structural soils. The experimental SWCC data were used to verify the proposed method. The fitting results showed that the proposed approaches resulted in good agreement between measurement and simulation. These functions can potentially be used as effective tools for indentifying hydraulic porosities in the structural mediums. PMID:23579828

  11. Sensitivity of limber pine (Pinus flexilis) seedling physiology to elevation, warming, and water availability across a timberline ecotone

    Microsoft Academic Search

    A. B. Moyes; C. Castanha; S. Ferrenberg; M. J. Germino; L. M. Kueppers

    2010-01-01

    Treelines occur where environmental gradients such as temperature become limiting to tree establishment, and are thus likely to respond to changes in climate. We collected gas exchange, water potential, and fluorescence measurements from limber pine (Pinus flexilis) seedlings planted into experimental plots at three elevations at Niwot Ridge, Colorado, ranging from within forest to alpine. At each site seeds from

  12. The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans

    PubMed Central

    Adeva-Andany, María M.; Carneiro-Freire, Natalia; Donapetry-García, Cristóbal; Rañal-Muíño, Eva; López-Pereiro, Yosua

    2014-01-01

    Human plasma is an aqueous solution that has to abide by chemical rules such as the principle of electrical neutrality and the constancy of the ionic product for water. These rules define the acid-base balance in the human body. According to the electroneutrality principle, plasma has to be electrically neutral and the sum of its cations equals the sum of its anions. In addition, the ionic product for water has to be constant. Therefore, the plasma concentration of hydrogen ions depends on the plasma ionic composition. Variations in the concentration of plasma ions that alter the relative proportion of anions and cations predictably lead to a change in the plasma concentration of hydrogen ions by driving adaptive adjustments in water ionization that allow plasma electroneutrality while maintaining constant the ionic product for water. The accumulation of plasma anions out of proportion of cations induces an electrical imbalance compensated by a fall of hydroxide ions that brings about a rise in hydrogen ions (acidosis). By contrast, the deficiency of chloride relative to sodium generates plasma alkalosis by increasing hydroxide ions. The adjustment of plasma bicarbonate concentration to these changes is an important compensatory mechanism that protects plasma pH from severe deviations. PMID:24877130

  13. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these unpredictable rainfall conditions, plant hydraulic traits (xylem and stomatal response to water availability) and morphological features (leaf and sapwood areas) must be coordinated - thus providing an ecohydrological interpretation of observed coordination (or homeostasis) among hydraulic traits. Moreover, the combinations of hydraulic traits and responses to drought that are optimal are found to depend on both total rainfall and its distribution during the growing season. Both drier conditions and more intense rainfall events interspaced by longer dry periods favor plants with high resistance to cavitation and delayed stomatal closure as soils dry. In contrast, plants in mesic conditions benefit from cavitation prevention through earlier stomatal closure. The proposed ecohydrological optimality criteria can be used as analytical tools to interpret variability in plant water use and predict trends in plant productivity and species composition under future climates.

  14. Land and water use characteristics in the vicinity of the Savannah River Site

    SciTech Connect

    Hamby, D.M.

    1991-03-01

    Routine operations at the Savannah River Site (SRS) result in the release of small amounts of radionuclides to the atmosphere and to the Savannah River. The resulting radiological doses to the offsite maximum individual and the offsite population within 50 miles of the SRS are estimated on a yearly basis. These estimates are generated using dose models prescribed for the commercial nuclear power industry by the Nuclear Regulatory Commission (NRC). The NRC provides default values for dose model parameters for facilities not having enough data to develop site-specific values. A survey of land and water use characteristics for the Savannah River area has been conducted to determine as many site-specific values as possible for inclusion in the dose models used at the SRS. These site parameters include local characteristics of meat, milk, and vegetable production; river recreational activities; and meat, milk, and vegetable consumption rates. The report that follows describes the origin of the NRC default values, the methodology for deriving regional data, the results of the study, and the derivations of region-specific usage and consumption rates. 33 refs., 3 figs., 8 tabs.

  15. Heat transfer characteristics for some coolant additives used for water cooled engines

    SciTech Connect

    Abou-Ziyan, H.Z.; Helali, A.H.B. [Helwan Univ., Cairo (Egypt)

    1996-12-31

    Engine coolants contain certain additives to prevent engine overheating or coolant freezing in cold environments. Coolants, also, contain corrosion and rust inhibitors, among other additives. As most engines are using engine cooling solutions, it is of interest to evaluate the effect of engine coolants on the boiling heat transfer coefficient. This has its direct impact on radiator size and environment. This paper describes the apparatus and the measurement techniques. Also, it presents the obtained boiling heat transfer results at different parameters. Three types of engine coolants and their mixtures in distilled water are evaluated, under sub-cooled and saturated boiling conditions. A profound effect of the presence of additives in the coolant, on heat transfer, was clear since changes of heat transfer for different coolants were likely to occur. The results showed that up to 180% improvement of boiling heat transfer coefficient is experienced with some types of coolants. However, at certain concentrations other coolants provide deterioration or not enhancement in the boiling heat transfer characteristics. This investigation proved that there are limitations, which are to be taken into consideration, for the composition of engine coolants in different environments. In warm climates, ethylene glycol should be kept at the minimum concentration required for dissolving other components, whereas borax is beneficial to the enhancement of the heat transfer characteristics.

  16. Marine plastic pollution in waters around Australia: characteristics, concentrations, and pathways.

    PubMed

    Reisser, Julia; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maira; Thums, Michele; Pattiaratchi, Charitha

    2013-01-01

    Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments ("microplastics", median length?=?2.8 mm, mean length?=?4.9 mm) resulting from the breakdown of larger objects made of polyethylene and polypropylene (e.g. packaging and fishing items). Mean sea surface plastic concentration was 4256.4 pieces km(-2), and after incorporating the effect of vertical wind mixing, this value increased to 8966.3 pieces km(-2). These plastics appear to be associated with a wide range of ocean currents that connect the sampled sites to their international and domestic sources, including populated areas of Australia's east coast. This study shows that plastic contamination levels in surface waters of Australia are similar to those in the Caribbean Sea and Gulf of Maine, but considerably lower than those found in the subtropical gyres and Mediterranean Sea. Microplastics such as the ones described here have the potential to affect organisms ranging from megafauna to small fish and zooplankton. PMID:24312224

  17. Marine Plastic Pollution in Waters around Australia: Characteristics, Concentrations, and Pathways

    PubMed Central

    Reisser, Julia; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maira; Thums, Michele; Pattiaratchi, Charitha

    2013-01-01

    Plastics represent the vast majority of human-made debris present in the oceans. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. We characterised and estimated the concentration of marine plastics in waters around Australia using surface net tows, and inferred their potential pathways using particle-tracking models and real drifter trajectories. The 839 marine plastics recorded were predominantly small fragments (“microplastics”, median length?=?2.8 mm, mean length?=?4.9 mm) resulting from the breakdown of larger objects made of polyethylene and polypropylene (e.g. packaging and fishing items). Mean sea surface plastic concentration was 4256.4 pieces km?2, and after incorporating the effect of vertical wind mixing, this value increased to 8966.3 pieces km?2. These plastics appear to be associated with a wide range of ocean currents that connect the sampled sites to their international and domestic sources, including populated areas of Australia's east coast. This study shows that plastic contamination levels in surface waters of Australia are similar to those in the Caribbean Sea and Gulf of Maine, but considerably lower than those found in the subtropical gyres and Mediterranean Sea. Microplastics such as the ones described here have the potential to affect organisms ranging from megafauna to small fish and zooplankton. PMID:24312224

  18. CHARACTERISTICS OF HEAT, WATER VAPOR AND CO2 FLUXES ABOVE A MOUNTAINOUS CRYPTOMERIA FOREST

    NASA Astrophysics Data System (ADS)

    Cheng, S.; Hsieh, C.; Wang, Y.; Hsiao, H.; Wey, T.

    2009-12-01

    Two eddy flux towers were built to study the characteristics of heat, water vapor, and carbon dioxide fluxes over the Sitou Forest Recreation Area of National Taiwan University, Taiwan. This forest area is located in middle Taiwan (23°39’50.1”N, 120°47’46.4”E) and in a valley, three sides surrounded by mountains. This site is a uniform-age (57 years old) managed Japanese Cedar (Cryptomeria japonica) forest that extends 1 km in the north-south direction and 0.8 km in the east-west direction. The mean canopy height is 26 m. The elevation of this area is between 800 - 2000 m a.s.l. and has a slope of 13.6 degree. The elevation of the flux towers is around 1250 m. This site is warm and humid. The average annual temperature and rainfall are 16.6 degC and 2635.18 mm, respectively. The average relative humidity is around 86%. From our eddy-covariance measurements, we have found that the fluxes measured at 28 and 33 m were the same. This demonstrates that a constant flux layer can be established even for a forest on a hilly terrain with a slope of 13.6 degree. Also, the flux-variance relations for heat and water vapor were found to follow Monin-Obukhov similarity theory. The similarity constants of temperature (CT) and humidity (Cq) are 1.25 and 1.5, respectively.

  19. Sauna, shower, and ice water immersion. Physiological responses to brief exposures to heat, cool, and cold. Part II. Circulation.

    PubMed

    Kauppinen, K

    1989-04-01

    Nine men were subjected to four temperature exposures: (A) sauna and head-out ice water immersion; (B) sauna and 15 degrees C shower; (C) sauna and room temperature; (D) head-out ice water immersion and room temperature. Exposures were repeated and ended with a 30-minute recovery. Heart rates were recorded continuously and blood pressures were determined six times during each experiment. Rate pressure products and indications of cardiac stroke work were calculated from the data. The results demonstrated decreased total peripheral resistance (TPR) to the blood flow in response to the heat of the sauna (C), with concurrent increase in cardiac oxygen demand and negligible increase in the stroke work. Cold exposures (D) increased the TPR. Cold did not increase the cardiac oxygen demand but increased the stroke work. The alternation of heat and cold (A) or cool (B) presented the most intensive strain on the heart. PMID:2736002

  20. Transcriptional and physiological response of fathead minnows (Pimephales promelas) exposed to urban waters entering into wildlife protected areas.

    PubMed

    Rodriguez-Jorquera, Ignacio A; Kroll, Kevin J; Toor, Gurpal S; Denslow, Nancy D

    2015-04-01

    The mission of protected areas is to conserve biodiversity and improve human welfare. To assess the effect of urban waters entering into protected areas, we performed 48-h whole-effluent exposures with fathead minnows, analyzing changes in steady state levels of mRNAs in the livers of exposed fish. Raw wastewater, treated city wastewater, and treated wastewater from a university were collected for exposures. All exposed fish showed altered mRNA levels of DNA damage-repair genes. Fish exposed to raw and treated wastewaters showed down-regulation of transcripts for key intermediates of cholesterol biosynthesis and elevated plasma cholesterol. The type of wastewater treatment influenced the response of gene transcription. Because of the relevance of some of the altered cellular pathways, we suggest that these effluents may cause deleterious effects on fish inside protected areas that receive these waters. Inclusion of research and mitigation efforts for this type of threat in protected areas management is advised. PMID:25656232

  1. Partition of compounds from gas to water and from gas to physiological saline at 310 K: Linear free energy relationships

    Microsoft Academic Search

    Michael H. Abraham; Adam Ibrahim; William E. Acree

    2007-01-01

    Data have been assembled on gas to water partition coefficients for 374 compounds at 310K. It is shown that an Abraham solvation equation with five descriptors can be used to correlate 350 such values, as logKW(310), with R2=0.994 and S.D.=0.154log units. Division into a training set and a test set shows that there is no bias in predictions and that

  2. Growth, physiology, and [delta] 13C of loblolly and shortleaf pine as affected by ozone and soil water deficit 

    E-print Network

    Elsik, Christine Golemboski

    1992-01-01

    divided by the number of moles of water transpired during the period of assimilation (Farquhar et al. 1989b). The expression for the ratio of the instantaneous rates of carbon assimilation, A, to transpiration, E, is: A g, (c. -ci) c, (1 -ci/cg E g... photosynthesis was linearly related to 0, in loblolly pine, and was accompanied by decreased foliar chlorophyll concenuation and decreased stomatal conductance, Decreased transpiration was attributable to 0, in both species. Ozone increased 5"Cms of loblolly...

  3. Physiological responses to short-term water and light stress in native and invasive plant species in southern California

    Microsoft Academic Search

    Jennifer L. Funk; Virginia A. Zachary

    2010-01-01

    As climate variability increases in low-resource environments, the ability of native and invasive species to tolerate stress\\u000a and respond to large, ephemeral resource pulses will strongly influence plant fitness and, consequently, competitive outcomes.\\u000a We examined how native and invasive species occurring in arid coastal sage scrub communities in southern California responded\\u000a to water and high-light stress. We also examined how

  4. Physiological and biochemical changes relating to postharvest splitting of sweet cherries affected by calcium application in hydrocooling water.

    PubMed

    Wang, Yan; Long, Lynn E

    2015-08-15

    Hydrocooling sweet cherries shortly after harvest (4h) and then transporting fruit in cold flume water during packing are used to maximize postharvest quality, but can cause fruit splitting. This study demonstrated that cherry fruit (two splitting-susceptible cultivars) absorbed Ca in a quadratic polynomial manner with increasing CaCl2 concentration from 0.2% to 2.0% in cold water (0°C) for 5 min, but did not take up Cl. The enhanced tissue Ca content reduced splitting potential by decreasing fruit soluble pectin release and increasing the splitting threshold. In contrast, depleting Ca from fruit tissue by EDTA or low pH, increased soluble pectin release and splitting potential. In a simulated commercial procedure, hydrocooling cherry fruit in appropriate CaCl2 solutions (i.e., 0.2-0.5%) for 5 min and then passing the fruit in cold flume water for 15 min increased fruit firmness, retarded losses in ascorbic acid, titratable acidity, and skin color, and reduced splitting and decay following 4 weeks of cold storage. PMID:25794746

  5. A comprehensive analysis of the physiological and anatomical components involved in higher water loss rates after leaf development at high humidity.

    PubMed

    Fanourakis, Dimitrios; Heuvelink, Ep; Carvalho, Susana M P

    2013-07-01

    To better understand the poor regulation of water loss after leaf development at high relative air humidity (RH), the relative importance of the physiological and anatomical components was analyzed focusing on cultivars with a contrasting sensitivity to elevated RH. The stomatal responsiveness to three closing stimuli (desiccation, abscisic acid feeding, light/dark transition), as well as several stomatal features (density, index, size and pore dimensions) and the cuticular transpiration rate (CTR) were determined in four rose cultivars, grown under moderate (60%) and high (95%) RH. Moreover, the effects of changes in stomatal density and pore dimensions on the stomatal conductance (gs) were quantified using a modified version of the Brown and Escombe equation. Higher water loss, as a result of plant growth at high RH, was primarily caused by an increase in residual gs, and to a lesser extent due to higher CTR. It was estimated that in leaflets subjected to desiccation the enhanced gs in high RH- as compared to moderate RH-grown plants was mostly due to poor stomatal functionality and to a lesser extent the combined result of higher stomatal density and longer pore length. It is concluded that the reduced degree and, specially, the reduced rate of stomatal closure are the primary causes of the large genotypic variation in the control of water loss in high RH-grown plants. Furthermore, it was found that although changes in stomatal length have no influence on stomatal functionality, changed anatomical features per se represent a significant and direct contribution to the increased water loss. PMID:23474196

  6. Distribution Characteristics of Phosphorus in the Sediments and Overlying Water of Poyang Lake

    PubMed Central

    Wang, Lingqing; Liang, Tao

    2015-01-01

    Phosphorus (P) is a key indicator of the aquatic organism growth and eutrophication in lakes. The distribution and speciation of P and its release characteristics from sediments were investigated by analyzing sediment and water samples collected during high flow and low flow periods. Results showed that the average concentrations (ranges) of total phosphorus (TP) in the surface and deep water were 0.06 mg L-1 (0.03–0.13 mg L-1) and 0.15 mg L-1 (0.06–0.33 mg L-1), respectively, while the average concentration (range) of TP in sediments was 709.17 mg kg-1 (544.76–932.11 mg kg-1). The concentrations of TP and different forms of P varied spatially in the surface sediments, displaying a decreasing trend from south to north. P also varied topographically from estuarine areas to lake areas. The vertical distribution of TP and different forms of P were observed to decrease as depth increased. The P concentrations during the low flow period were higher than those during the high flow period. Inorganic phosphorus (IP) was the dominant form of P, accounting for 61%–82% of TP. The concentration of bioavailable phosphorus in sediments was relatively large, indicating a high risk of release to overlying water. The simulation experiment of P release from sediments showed that the release was relatively fast in the first 0-5 min and then decreased to a plateau after 1 hr. Approximately 84–89% of the maximum amount of P was released during the first hour. PMID:25938758

  7. Muscle Physiology

    NSDL National Science Digital Library

    2000-01-01

    The Muscle Physiology Lab at the University of California-San Diego provides this comprehensive source of information on the neuromuscular system. The Web site appears as a extensive menu of subtopics, each leading to pages of detailed text and diagrams. Students studying muscle structure and function should find this well-organized and authoritative resource extremely useful. The Web site also includes a search tool for quickly finding pages of interest, and a list of related links for additional information.

  8. Physiological traits of Penicillium glabrum strain LCP 08.5568, a filamentous fungus isolated from bottled aromatized mineral water.

    PubMed

    Nevarez, L; Vasseur, V; Le Madec, A; Le Bras, M A; Coroller, L; Leguérinel, I; Barbier, G

    2009-04-15

    Penicillium glabrum is a ubiquitous fungus distributed world wide. This fungus is a frequent contaminant in the food manufacturing industry. Environmental factors such as temperature, water activity and pH have a great influence on fungal development. In this study, a strain of P. glabrum referenced to as LCP 08.5568, has been isolated from a bottle of aromatized mineral water. The effects of temperature, a(w) and pH on radial growth rate were assessed on Czapeck Yeast Agar (CYA) medium. Models derived from the cardinal model with inflection [Rosso et al., 1993 An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. J. Theor. Bio. 162, 447-463.] were used to fit the experimental data and determine for each factor, the cardinal parameters (minimum, optimum and maximum). Precise characterisation of the growth conditions for such a fungal contaminant, has an evident interest to understand and to prevent spoilage of food products. PMID:19233496

  9. Water Landing Characteristics of a 1/6-Scale Model Reentry Capsule with an 80-Inch Heat Shield

    NASA Technical Reports Server (NTRS)

    1959-01-01

    Water Landing Characteristics of a 1/6-Scale Model Reentry Capsule with an 80-Inch Heat Shield. Variables for the reentry capsule water landing tests were flight path, vertical contact velocity, and contact attitude. The capsule weighed 1900 pounds with a center of gravity 16.8 inches above maximum diameter. [Entire movie available on DVD from CASI as Doc ID 20070030950. Contact help@sti.nasa.gov

  10. Water tree characteristics in low-density polyethylene under power-frequency voltages with high-frequency components

    Microsoft Academic Search

    Hidenori Suzuki; Yoshimichi Ohki; Yoshinobu Nakamichi; Kohji Ajiki

    1996-01-01

    For magnetic levitation railway systems using linear synchronous motors, pulse-width-modulation inverters and polymer insulated cables are used for driving cars and feeding electricity, respectively. This means that ac voltages with many harmonics induced by inverters are applied to cables. Water-tree characteristics have been investigated for low-density polyethylene using power-frequency ac voltages with high-frequency components. It was found that water trees

  11. Characteristics of the ratio of dissolved cadmium to phosphate in subtropical coastal waters of Ishigaki Island, Okinawa, Japan

    Microsoft Academic Search

    Kazuo Abe; Kouki Fukuoka; Toru Shimoda

    2011-01-01

    The ratio of dissolved cadmium (Cd) to phosphate (PO4) in the subtropical coastal area of Ishigaki Island, Okinawa, Japan, was investigated. Twenty vertical seawater samplings\\u000a were carried out once a month from May 2008 to January 2010. In order to examine how the Cd\\/PO4 ratio in seawater varies with the oceanographic conditions (i.e., the water temperature–salinity characteristics), the water\\u000a masses

  12. Tool to address green roof widespread implementation effect in flood characteristics for water management planning

    NASA Astrophysics Data System (ADS)

    Tassi, R.; Lorenzini, F.; Allasia, D. G.

    2015-06-01

    In the last decades, new approaches were adopted to manage stormwater as close to its source as possible through technologies and devices that preserve and recreate natural landscape features. Green Roofs (GR) are examples of these devices that are also incentivized by city's stormwater management plans. Several studies show that GR decreases on-site runoff from impervious surfaces, however, the analysis of the effect of widespread implementation of GR in the flood characteristics at the urban basin scale in subtropical areas are little discussed, mainly because of the absence of data. Thereby, this paper shows results related to the monitoring of an extensive modular GR under subtropical weather conditions, the development of a rainfall-runoff model based on the modified Curve Number (CN) and SCS Triangular Unit Hydrograph (TUH) methods and the analysis of large-scale impact of GR by modelling different basins. The model was calibrated against observed data and showed that GR absorbed almost all the smaller storms and reduced runoff even during the most intense rainfall. The overall CN was estimated in 83 (consistent with available literature) with the shape of hydrographs well reproduced. Large-scale modelling (in basins ranging from 0.03 ha to several square kilometers) showed that the widespread use of GRs reduced peak flows (volumes) around 57% (48%) at source and 38% (32%) at the basin scale. Thus, this research validated a tool for the assessment of structural management measures (specifically GR) to address changes in flood characteristics in the city's water management planning. From the application of this model it was concluded that even if the efficiency of GR decreases as the basin scale increase they still provide a good option to cope with urbanization impact.

  13. [Chemical characteristics of the rhizosphere soil of water spinach cultivars differing in Cd accumulation].

    PubMed

    Gong, Yu-Lian; Yang, Zhong-Yi

    2014-08-01

    A rhizobox experiment was conducted to investigate the chemical characteristics of the rhizosphere soils of two water spinach cultivars differing in Cd accumulation, QLQ (a low-Cd cultivar) and T308 (a high-Cd cultivar). The results showed that the diethylenetriamine pentacetate acid extractable Cd (DTPA-Cd) concentration in the rhizos-phere soil of QLQ was significantly higher than that of T308 (P < 0.05). pH and Eh in the rhizosphere soil of QLQ were significantly higher than those of T308 (P < 0.05), while EC was opposite. Contents of organic matter and dissolved organic matter (DOM) in the rhizosphere soil of QLQ were both higher than those of T308. In contaminated soil, the composition and concentration of low molecular weight organic acids in the rhizosphere between the two cultivars were both different. Acetic, propionic, citric and fumaric acids were detected in the rhizosphere soil of T308, and only citric and fumaric acids were detected in that of QLQ. The total concentration of low molecular weight organic acids in the rhizosphere soil of QLQ (1.93 nmol x g(-1) DM) was lower than that of T308 (15.11 nmol x g(-1) DM) (P < 0.01). Compared with the high-Cd cultivar (T308), the chemical characteristics of the rhizosphere soil of the low-Cd cultivar (QLQ) were obviously distinct, i. e., the relatively higher content of organic matter, the lower content of low molecular weight organic acids with a specific composition, less acidification of soil, and a lower ability in reduction, correspondingly lowering the mobility of Cd in soil and reducing Cd accumulation by plant. PMID:25509092

  14. Characteristics of water quality and streamflow, Passaic River basin above Little Falls, New Jersey

    USGS Publications Warehouse

    Anderson, Peter W.; Faust, Samuel Denton

    1973-01-01

    The findings of a problem-oriented river-system investigation of the water-quality and streamflow characteristics of the Passaic River above Little Falls, N.J. (drainage area 762 sq mi) are described. Information on streamflow duration, time-of-travel measurements, and analyses of chemical, biochemical, and physical water quality are summarized. This information is used to define relations between water quality, streamflow, geology, and environmental development in the basin's hydrologic system. The existence, nature, and magnitude of long-term trends in stream quality--as measured by dissolved solids, chloride, dissolved oxygen, biochemical oxygen demand, ammonia, nitrate, and turbidity--and in streamflow toward either improvement or deterioration are appraised at selected sites within the river system. The quality of streams in the upper Passaic River basin in northeastern New Jersey is shown to be deteriorating with time. For example, biochemical oxygen demand, an indirect measure of organic matter in a stream, is increasing at most stream-quality sampling sites. Similarly, the dissolved-solids content, a measure of inorganic matter, also is increasing. These observations suggest that the Passaic River system is being used more and more as a medium for the disposal of industrial and municipal waste waters. Dissolved oxygen, an essential ingredient for the natural purification of streams receiving waste discharges, is undersaturated (that is, below theoretical solubility levels) at all sampling sites and is decreasing with time at most sites. This is another indication of the general deterioration of stream quality in the upper basin. It also indicates that the ability of the river system to receive, transport, and assimilate wastes, although exceeded now only for short periods during the summer months, may be exceeded more continually in the future if present trends hold. Decreasing ratios of ammonia to nitrate in a downstream direction on the main stem Passaic River suggests that nitrification (the biochemical conversion of ammonia to nitrate) as well as microbiological decomposition of organic matter (waste waters) is contributing to the continued and increasing undersaturation of dissolved oxygen in the river system. Passaic River streams are grouped into five general regions of isochemical quality on the basis of predominant constituents and dissolved-solids content during low flows. The predominant cations in all but one region are calcium and magnesium (exceeding 50 percent of total cations) ; in that region, where man's activities probably have altered the natural stream waters, the percentage of sodium and potassium equals that of calcium and magnesium. In two of the five regions, the predominant anion is bicarbonate; a combination of sulfate, chloride, and nitrate is predominant in the other three regions. Dissolved-solids content during low flows generally ranges from 100 to 600 milligrams per liter. Several time-of-travel measurements within the basin are reported. These data provide reasonable estimates of the time required for soluble contaminants to pass through particular parts of the river system. For example, the peak concentration of a contaminant injected into the river system at Chatham during extreme low flow would be expected to travel to Little Falls, about 31 miles, in about 13 days; but at medium flow, in about 5 days.

  15. Characteristics of subzero startup and water\\/ice formation on the catalyst layer in a polymer electrolyte fuel cell

    Microsoft Academic Search

    Shanhai Ge; Chao-Yang Wang

    2007-01-01

    This work experimentally explores the fundamental characteristics of a polymer electrolyte fuel cell (PEFC) during subzero startup, which encompasses gas purge, cool down, startup from a subfreezing temperature, and finally warm up. In addition to the temperature, high-frequency resistance (HFR) and voltage measurements, direct observations of water or ice formation on the catalyst layer (CL) surface have been carried out

  16. The Use of Bacterial Adherence to Hydrocarbons (BATH) Assay in Evaluation of the Hydrophobic Surface Characteristics of Potential Water Pathogens

    EPA Science Inventory

    Bacterial adherence to hydrocarbons, BATH, is a method for determining the hydrophobic surface characteristics of bacterial cells. The strain?s affinity for water is evaluated by thoroughly mixing a culture and hydrocarbon suspension and then evaluating the decrease in optical de...

  17. A Comparison of Analysis Methods of Pipe Failure Characteristics Based on Maintenance Records of Water Distribution System

    Microsoft Academic Search

    Wang Yi; Tian Yimei

    2010-01-01

    The characteristic data applied for establishing predicting models of pipe failure in water distribution system (WDS) should be examined and screened in the first place. The effects of different way of data processing based on a series on maintenance records are compared, which includes a classification method by Bayesian theorem, a hypothesis testing by analysis of variance and an association

  18. SPECTRA CHARACTERISTICS OF WATER EXTRACTABLE ORGANIC MATTER FROM SOILS OF DIFFERENT LAND USES IN A SUBARCTIC ALASKA ENVIRONMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to determine characteristics of soil water extractable organic matter (WEOM) under different land uses in a subarctic environment. Soil (Volkmar, Aquic Eutrocrepts) samples were taken in October, 2005 from forestry, agricultural, and USDA Conservation Reserve Prog...

  19. A Method to Recover Useful Geothermal-Reservoir Parameters from Production Characteristic Curves (2) Hot Water Reservoirs

    Microsoft Academic Search

    E. Iglesias; V. Arellano; R. Molinar

    1983-01-01

    In this paper we develop and demonstrate a method to estimate the reservoir pressure, a mass productivity index, and a thermal power productivity index for vertical water-fed geothermal wells, from its production characteristic (also called output) curves. In addition, the method allows to estimate the radius of influence of the well, provided that a value of the reservoir transmisivity is

  20. Renal Water Molecular Diffusion Characteristics in Healthy Native Kidneys: Assessment with Diffusion Tensor MR Imaging

    PubMed Central

    Zheng, Zhenfeng; Shi, Huilan; Zhang, Jing; Zhang, Yunting

    2014-01-01

    Background To explore the characteristics of diffusion tensor imaging (DTI) and magnetic resonance (MR) imaging in healthy native kidneys. Methods Seventy-three patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar (SE-EPI) sequences accompanied by an array spatial sensitivity encoding technique (ASSET). Cortical and medullary mean, axial and radial diffusivity (MD, AD and RD), fractional anisotropy (FA) and primary, secondary and tertiary eigenvalues (?1, ?2, ?3) were analysed in both kidneys and in different genders. Results Cortical MD, ?2, ?3, and RD values were higher than corresponding medullary values. The cortical FA value was lower than the medullary FA value. Medullary ?1 and RD values in the left kidney were lower than in the right kidney. Medullary ?2, and ?3 values in women were higher than those in men. Medullary FA values in women were lower than those in men. Medullary FA (r?=?0.351, P?=?0.002) and ?1 (r?=?0.277, P?=?0.018) positively correlated with eGFR. Medullary FA (r?=??0.25, P?=?0.033) negatively correlated with age. Conclusions Renal water molecular diffusion differences exist in human kidneys and genders. Age and eGFR correlate with medullary FA and primary eigenvalue. PMID:25470776

  1. Scaling Characteristics of Developing Sea Breezes Simulated in a Water Tank

    NASA Astrophysics Data System (ADS)

    Yuan, Renmin; Sun, Jianning; Luo, Tao; Wu, Xuping

    2013-09-01

    Sea-breeze circulations in a stably stratified environment have been simulated in a water tank. The floor of the tank was divided into two halves representing land and sea; the land side was heated from the bottom of the tank, and the sea side was insulated by an underlying sponge slab. The temperature profiles over both land and sea sides, the land-sea temperature difference, and the horizontal temperature distributions were measured. Particle tracking velocimetry was applied to obtain the two-dimensional velocity field orthogonal to the coastline. It was shown that the overall flow consists of a closed circulation caused by the horizontal temperature difference between land and sea, and a strong updraft occurring at the sea-breeze front. The dimensionless governing parameters are calculated from the measurements and used to characterize the developing sea breezes. The analysis confirms the scaling laws for sea-breeze velocity and depth. The results indicate that the scaling characteristics of the sea-breeze translation speed during the developing period are different to those during the following maintaining period. A criterion for the onset of the sea breeze is proposed based on these results.

  2. Statistical characteristics of cloud variability. Part 1: Retrieved cloud liquid water path at three ARM sites

    NASA Astrophysics Data System (ADS)

    Huang, Dong; Campos, Edwin; Liu, Yangang

    2014-09-01

    Statistical characteristics of cloud variability are examined for their dependence on averaging scales and best representation of probability density function with the decade-long retrieval products of cloud liquid water path (LWP) from the tropical western Pacific (TWP), Southern Great Plains (SGP), and North Slope of Alaska (NSA) sites of the Department of Energy's Atmospheric Radiation Measurement Program. The statistical moments of LWP show some seasonal variation at the SGP and NSA sites but not much at the TWP site. It is found that the standard deviation, relative dispersion (the ratio of the standard deviation to the mean), and skewness all quickly increase with the averaging window size when the window size is small and become more or less flat when the window size exceeds 12 h. On average, the cloud LWP at the TWP site has the largest values of standard deviation, relative dispersion, and skewness, whereas the NSA site exhibits the least. Correlation analysis shows that there is a positive correlation between the mean LWP and the standard deviation. The skewness is found to be closely related to the relative dispersion with a correlation coefficient of 0.6. The comparison further shows that the lognormal, Weibull, and gamma distributions reasonably explain the observed relationship between skewness and relative dispersion over a wide range of scales.

  3. Understanding effects of water characteristics on natural organic matter treatability by PACl and a novel PACl-chitosan coagulants.

    PubMed

    Ng, Mega; Liu, Sanly; Chow, Christopher W K; Drikas, Mary; Amal, Rose; Lim, May

    2013-12-15

    In this study, we investigated the relationship between water characteristics and removal of natural organic matter (NOM) using polyaluminium chloride (PACl) and a newly developed coagulant obtained by hybridising PACl with chitosan (PACl-chitosan) for two different types of water. Using UV-visible spectroscopy analysis, we showed that PACl-chitosan is more effective than PACl for treating water samples that contain higher levels of activated polyhydroxyaromatic moieties. As a result, a lower level of total trihalomethanes formation potential (THMFP) was detected for synthetic water treated with PACl-chitosan coagulant compared to water treated with PACl only. In contrast, no difference was observed for the total THMFP that were formed following coagulation with either coagulant, for water sample containing the same level of organic carbon concentration, but lower levels of polyhydroxyaromatic moieties. Our work shows how the complex characteristics and interactions of organic matter with coagulant component can affect the outcome of the treatment process, and in this case, enhance the treatment. The use of PACl-chitosan was also shown to produce larger floc for both water samples; this again, can lead to better removal. PMID:24220196

  4. Space Physiology within an Exercise Physiology Curriculum

    ERIC Educational Resources Information Center

    Carter, Jason R.; West, John B.

    2013-01-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of…

  5. Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations - Method, validation, and data characteristics

    NASA Technical Reports Server (NTRS)

    Rind, D.; Chiou, E.-W.; Chu, W.; Oltmans, S.; Lerner, J.; Larsen, J.; Mccormick, M. P.; Mcmaster, L.

    1993-01-01

    Results are presented of water vapor observations in the troposphere and stratosphere performed by the Stratospheric Aerosol and Gas Experiment II solar occultation instrument, and the analysis procedure, the instrument errors, and data characteristics are discussed. The results are compared with correlative in situ measurements and other satellite data. The features of the data set collected between 1985 and 1989 include an increase in middle- and upper-tropospheric water vapor during northern hemisphere summer and autumn; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds.

  6. Physiological adjustments of sand gazelles (Gazella subgutturosa) to a boom-or-bust economy: standard fasting metabolic rate, total evaporative water loss, and changes in the sizes of organs during food and water restriction.

    PubMed

    Ostrowski, Stephane; Mesochina, Pascal; Williams, Joseph B

    2006-01-01

    To test the hypothesis that desert ungulates adjust their physiology in response to long-term food and water restriction, we established three groups of sand gazelles (Gazella subgutturosa): one that was provided food and water (n = 6; CTRL) ad lib. for 4 mo, one that received ad lib. food and water for the same period but was deprived of food and water for the last 4.5 d (n = 6; EXPT(1)), and one that was exposed to 4 mo of progressive food and water restriction, an experimental regime designed to mimic conditions in a natural desert setting (n = 6; EXPT(2)). At the end of the 4-mo experiment, we measured standard fasting metabolic rate (SFMR) and total evaporative water loss (TEWL) of all sand gazelles and determined lean dry mass of organs of gazelles in CTRL and EXPT(2). Gazelles in CTRL had a mean SFMR of 2,524 +/- 194 kJ d(-1), whereas gazelles in EXPT(1) and EXPT(2) had SFMRs of 2,101+/- 232 and 1,365 +/- 182 kJ d(-1), respectively, values that differed significantly when we controlled for differences in body mass. Gazelles had TEWLs of 151.1 +/- 18.2, 138.5 +/- 17.53, and 98.4 +/- 27.2 g H(2)O d(-1) in CTRL, EXPT(1), and EXPT(2), respectively. For the latter group, mass-independent TEWL was 27.1% of the value for CTRL. We found that normally hydrated sand gazelles had a low mass-adjusted TEWL compared with other arid-zone ungulates: 13.6 g H(2)O kg(-0.898) d(-1), only 17.1% of allometric predictions, the lowest ever measured in an arid-zone ungulate. After 4 mo of progressive food and water restriction, dry lean mass of liver, heart, and muscle of gazelles in EXPT(2) was significantly less than that of these same organs in CTRL, even when we controlled for body mass decrease. Decreases in the dry lean mass of liver explained 70.4% of the variance of SFMR in food- and water-restricted gazelles. As oxygen demands decreased because of reduced organ sizes, gazelles lost less evaporative water, probably because of a decreased respiratory water loss. PMID:16826507

  7. Retrieval of characteristic parameters for water vapour transmittance in the development of ground based sun-sky radiometric measurements of columnar water vapour

    NASA Astrophysics Data System (ADS)

    Campanelli, M.; Nakajima, T.; Khatri, P.; Takamura, T.; Uchiyama, A.; Estelles, V.; Liberti, G. L.; Malvestuto, V.

    2013-09-01

    Sun-sky radiometers are instruments created for aerosol study, but they can measure in the water vapour absorption band allowing the estimation of columnar water vapour in clear sky simultaneously with aerosol characteristics, with high temporal resolution. A new methodology, cheap and easy to implement, is presented for estimating calibration parameters (i.e. characteristic parameters of the atmospheric transmittance and solar calibration constant) directly from the sun-sky radiometers measurements. To initiate the proposed methodology some seasonal independent measurements of columnar water vapour taken over a large range of solar zenith angle simultaneously with the sun-sky radiometer measurements, are needed. In this work the Surface Humidity Method (SHM) was developed allowing to initiate the procedure with columnar water vapour estimated by standard surface meteorological observation (temperature, pressure and relative humidity). The time pattern of columnar water vapour from sun-sky radiometer was compared with simultaneous measurements from microwave radiometer and radiosondings showing respectively a total correlation of 0.98, 0.96 and a total median difference of 2.24 and -0.65 mm. The accordance with radiosondings was found within the uncertainty of the methodology (varying from 10 to 16%) independently on the amount of atmospheric water vapour.

  8. Responses of Fraxinus excelsior L. seedlings to ambient ozone exposure in urban and mountain areas based on physiological characteristics and antioxidant activity.

    PubMed

    Parvanova, Petya; Tzvetkova, Nikolina; Bratanova-Doncheva, Svetla; Chipev, Nesho; Fikova, Radka; Donev, Evgeni

    2013-07-01

    Effects of ozone on the sensitive tree species Fraxinus excelsior L. exposed to ambient air were investigated. The dynamics of photosynthesis, transpiration, stomatal conductance and the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in three-year-old ash seedlings were studied during a four-month period (June-September). Seedlings were exposed to ambient ozone in an urban (the Central City Park of Sofia - Borisova Gradina) and a mountain (Plana Mountain) area in Bulgaria. The sites were located near climate monitoring stations, providing data on ozone concentrations and meteorological parameters. Ozone exposure at the mountain site (AOT40) was more than two times higher compared to the urban site. Significantly higher values of sun radiation, transpiration, stomatal conductance and enzyme activity at the mountain site were also observed. At the urban site higher values of temperature and air humidity were registered. Effects of the measured variables on ash seedlings were complex and interdependent. No direct effect of ozone concentration in ambient air on the leaf physiology and biochemistry could be proved. However, intensified SOD and CAT activity in the presence of elevated ozone suggested antioxidant reaction in response to ozone uptake. PMID:23760537

  9. [Hydro-chemical characteristics in the Danjiangkou Reservoir (water source area of the middle route of the south to north water transfer project), China].

    PubMed

    Li, Si-yue; Cheng, Xiao-li; Gu, Sheng; Li, Jia; Zhang, Quan-fa

    2008-08-01

    TDS, pH and major ions in the Danjiangkou Reservoir, the water source area of the Middle Route of the South to North Water Transfer Project of China were monitored during the period of 2004-2006 to systemically analyze hydro-chemical characteristics and water chemistry type. Analysis of variance (ANOVA) and correlation analysis were performed to explore their spatio-temporal pattern. The results show that the water is of low mineralized degree with a total dissolved solid ranging from 149.9-291.2 mg x L(-1), and soft water with a total hardness ranging from 40-50 mg x L(-1) x HCO3- accounts for 77.54%-77.87% of the total major anions with a content of 122.5-170.0 mg x L(-1), while Ca2+ accounts for 70.66%-77.93% of the total major cations with a content of 37.1-43.2 mg x L(-1), and the water is of a HCO3- -Ca type. Major ions show similar spatial variations, decreasing downstream in the Danjiang Reservoir, and reaching the lowest values in the Hanjiang Reservoir. The temporal and seasonal variations of the hydro-chemical characteristics show that the concentrations of major ions in the dry season are larger than those in the wet season. Hydro-chemical characteristics in the reservoir are mainly determined by the rock weatherization, while and anthropogenic activities in the upper-stream and the reservoir region have been influencing the NO3- concentration. Finally, conservation strategies of water resource in the reservoir and its upper stream are discussed. PMID:18839558

  10. Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

    NASA Astrophysics Data System (ADS)

    Terpugova, S. A.; Polkin, V. V.; Panchenko, M. V.; Golobokova, L. P.; Kozlov, V. S.; Shmargunov, V. P.; Shevchenko, V. P.; Lisitzin, A. P.

    2009-04-01

    The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV "Professor Shtockman"; 53 and 54-th cruises of RV "Akademik Mstislav Keldysh"). Measurements of aerosol microphysical characteristics were carried out by means of the automated mobile aerosol complex consisting of nephelometer, photoelectric counter and aethalometer. The aerosol disperse composition was studied with photoelectric counter in 256 size intervals from 0.4 to 10 m. About 1500 series of measurements were carried out in White Sea, and about 1400 series in Kara Sea. Chemical characteristics of aerosol were determined from samples collected on aerosol filters (92 samples were collected in White Sea and 48 in Kara Sea). The ion composition was determined under laboratory conditions. The H+, Na+, K+, Ca2+, Mg2+, NH4+, Cl-, NO3-, HCO3-, SO42- ions were under examination. Comparing aerosol characteristics of two seas, one can note that the mean values of the aerosol content parameters in Kara Sea are less than in White Sea. The ratio of the aerosol mass concentration are from 2 (Yamal Peninsula, northern part of Novaya Zemlya) to 9 times (Blagopoluchia Bay, Ob' Gulf). The differences in the concentration of black carbon vary from 3 (Yamal Peninsula) to 17 times (Blagopoluchia Bay). The differences in the aerosol number concentration NA are not so big. The values NA near Kara Gate, Yamal Peninsula and northern part of Novaya Zemlya are practically the same as in White Sea. The concentration NA at Ob' gulf is one order of magnitude less than in White sea. The obtained aerosol volume size distributions were approximated by the sums of two fractions, submicron and coarse, with lognormal size distributions. The mean volume size distribution of submicron fraction in White Sea is approximated by the distribution with the variance of the radius logarithm s=0.6 and modal radius Rs0=0.096 m, and the total volume concentration V s=37.6 m3cm-3, and the distribution of coarse fraction has the following parameters c=1.19, Rc0=2.15 m and V c=19.7 m3cm-3. The distribution of submicron particles in the central part of Kara sea is approximated by lognormal function with parameters s=0.443, Rs0=0.215 m and V s=1.01 m3cm-3, while parameters of the coarse fraction are c=0.825, Rc=2.04 m and V c=3.29 m3cm-3. The main differences in the size spectra in White and Kara Seas are observed in the submicron size range R < 1 m. The higher values of the distribution function in this range are explained by the fact that White Sea, on the contrary to Kara Sea, is internal sea, so near-water aerosol undergoes the effect of continental sources, which can have anthropogenic origin and generate great amount of submicron aerosol, which is transferred to long distances. Comparison of ion composition of aerosol over White and Kara Seas has shown that the concentrations of practically all ions, on average, are greater in the region of White Sea. The enhancement of ions of marine origin (Cl-, Na+, Mg2+) is from 1.4 to 1.7 times. This differences in "continental" ions (Ca2+, SO42-, NO3-, NH4+) reach 2.3÷3.7 times. The exception is the ion K+, the concentration of which in Kara Sea is 1.4 times greater. To estimate the contribution of continental and marine sources into formation of the chemical composition of near-water aerosol, the technique was applied using the factors V cont and V ocean representing the fraction of the mass concentration of ions of continental and marine origin, respectively. Depending on the hydrometeorological conditions, V cont varies in wide range (~ 0.1÷1), and its mean value in White Sea is 0.38 (respectively, V ocean = 0.62). That means, the contribution of continental sources is essential, although the role of marine sources prevails on average. The mean value of V cont in central regions of Kara Sea is 0.3, but this factor in the regions adjacent to the continent can reach the values of 0.6÷0.8

  11. Pulsed Arc Electrohydraulic Discharge characteristics and plasma parameters of sludge-water

    Microsoft Academic Search

    O. L. Li; J. S. Chang; Yiping Guo

    2009-01-01

    Storm water detention\\/ retention ponds are designed to settle and trap sediments carried by storm water runoff. However, as the service time of the facilities increases, the accumulation of pollutants in sediment also increases hence the contaminants of a liquid fraction in storm-water sediment (sludge-water) should be treated before discharge to the river. The Pulsed Arc Electrohydraulic Discharge (PAED) is

  12. Physicochemical characteristics of drip waters: Influence on mineralogy of recent cave carbonate precipitates

    NASA Astrophysics Data System (ADS)

    Riechelmann, Sylvia; Schröder-Ritzrau, Andrea; Wassenburg, Jasper A.; Richter, Detlev K.; Riechelmann, Dana FC; Terente, Mihai; Constantin, Silviu; Immenhauser, Adrian

    2015-04-01

    Speleothems are one of the most intensively explored archives of palaeoclimate variability in continental settings. Considerable advances with respect to climatic and cave forcing of drip characteristics and related speleothem proxy data have been made during the last decades. The parameters, however, that control speleothem mineralogy and its changes with time and space are still poorly understood. In order to shed light on processes influencing speleothem mineralogy, precipitation experiments of recent carbonate crystals on watch glasses and glass plates were performed in seven selected caves. These include three caves in Germany as well as Morocco and one cave in Romania, which are situated in both limestone and dolostone. Drip water sites of these caves were analysed for their fluid Mg/Ca molar ratio, pH, degree of saturation for calcite and aragonite and drip rates. Corresponding precipitates were analysed with respect to their mineralogy using a high resolution scanning electron microscope (SEM). The following results are found: High fluid Mg/Ca ratios are observed only for caves situated in dolostone, hence the hostrock lithology indirectly controls the carbonate mineralogy of speleothems. The precipitation of aragonite in place of calcite occurred only in dolostone caves and is bound to very specific conditions, which are: high fluid Mg/Ca ratios (? 0.5), high fluid pH (> 8.2) and low fluid saturation indices for calcite (< 0.8). These specific conditions are induced by slow drip rates of < 0.2 ml/min (often under more arid conditions), causing the precipitation of calcite / aragonite prior to reaching the stalagmite top. Due to this, fluid chemistry is altered, which in turn leads to changes in carbonate mineralogy and geochemistry on the stalagmite top. Interestingly, all of the above mentioned factors must act in a concerted manner. If this is not the case, calcite is the dominant phase. The threshold, where only aragonite precipitates is at fluid Mg/Ca ratios exceeding 2.4. Generally, calcite growth is inhibited at high fluid Mg/Ca ratios and hence, aragonite precipitation is kinetically stabilized. On the other hand, aragonite precipitation is possibly inhibited by some types of organic compounds leading to calcite precipitation, whilst it is induced in other cases. Based on the data shown here, the parameters inducing aragonite precipitation are now clearly better understood. Thus, conclusions of drip water palaeo-conditions from aragonite speleothems can be drawn, which leads to an improved understanding of aragonite speleothems as climate archives.

  13. Behavioral, physical, and physiological variation among litters of cloned pigs 

    E-print Network

    Archer, Gregory Scott

    2002-01-01

    The variability of behavioral, physical, and physiological characteristics among cloned animals has yet to be studied. Through a series of behavioral, physical and physiological measurements, we quantified the variation in food preference...

  14. Species-specific physiological response by the cold-water corals Lophelia pertusa and Madrepora oculata to variations within their natural temperature range

    NASA Astrophysics Data System (ADS)

    Naumann, Malik S.; Orejas, Covadonga; Ferrier-Pagès, Christine

    2014-01-01

    The scleractinian cold-water corals (CWC) Lophelia pertusa and Madrepora oculata represent two major deep-sea reef-forming species that act as key ecosystem engineers over a wide temperature range, extending from the northern Atlantic (ca. 5-9 °C) to the Mediterranean Sea (ca. 11-13 °C). Recent research suggests that environmental parameters, such as food supply, settling substrate availability or aragonite saturation state may represent important precursors controlling habitat suitability for CWC. However, the effect of one principal environmental factor, temperature, on CWC key physiological processes is still unknown. In order to evaluate this effect on calcification, respiration, and dissolved organic carbon (DOC) net flux, colonies of Mediterranean L. pertusa and M. oculata were acclimated in aquaria to three temperatures (12, 9 and 6 °C), by consecutive decrements of 1 month duration. L. pertusa and M. oculata maintained at Mediterranean control conditions (i.e. 12 °C) displayed constant rates, on average respiring 4.8 and 4.0 ?mol O2 cm-2 coral surface area d-1, calcifying 22.3 and 12.3 ?mol CaCO3 g-1 skeletal dry weight d-1 and net releasing 2.6 and 3.1 ?mol DOC cm-2 coral surface area d-1, respectively. Respiration of L. pertusa was not affected by lowered temperatures, while M. oculata respiration declined significantly (by 48%) when temperature decreased to 9 °C and 6 °C relative to controls. L. pertusa calcification at 9 °C was similar to controls, but decreased significantly (by 58%) at 6 °C. For M. oculata, calcification declined by 41% at 9 °C and by 69% at 6 °C. DOC net flux was similar throughout the experiment for both CWC. These findings reveal species-specific physiological responses by CWC within their natural temperature range. L. pertusa shows thermal acclimation in respiration and calcification, while these mechanisms appear largely absent in M. oculata. Conclusively, species-specific thermal acclimation may significantly affect the occurrence and local abundance of cosmopolitan CWC species, consequently influencing their important role in habitat engineering and ecosystem functioning in various thermal environments.

  15. Analyzing the ecosystem carbon and hydrologic characteristics of forested wetland using a

    E-print Network

    Analyzing the ecosystem carbon and hydrologic characteristics of forested wetland using biogeochemical model, Wetland-DNDC, was applied to analyze the carbon and hydrologic characteristics of forested, energy, and water in forested wetlands. Modeled carbon dynamics depends on physiological plant factors

  16. A comparison of process characteristics for the recovery of tritium from heavy water and light water systems

    Microsoft Academic Search

    K. M. Kalyanam; S. K. Sood

    1988-01-01

    A number of facilities have been either constructed or are operating to extract tritium from the heavy water moderator systems of nuclear reactors. However it is expected that most fusion reactor concepts would require the recovery of tritium from light water coolant or blanket systems. This paper highlights the significant differences between recovery of tritium from HâO and DâO in

  17. Effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees.

    PubMed

    Räsänen, Janne V; Holopainen, Toini; Joutsensaari, Jorma; Ndam, Collins; Pasanen, Pertti; Rinnan, Åsmund; Kivimäenpää, Minna

    2013-12-01

    Trees can improve air quality by capturing particles in their foliage. We determined the particle capture efficiencies of coniferous Pinus sylvestris and three broadleaved species: Betula pendula, Betula pubescens and Tilia vulgaris in a wind tunnel using NaCl particles. The importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. The results confirm earlier findings of more efficient particle capture by conifers compared to broadleaved plants. The particle capture efficiency of P. sylvestris (0.21%) was significantly higher than those of B. pubescens, T. vulgaris and B. pendula (0.083%, 0.047%, 0.043%, respectively). The small leaf size of P. sylvestris was the major characteristic that increased particle capture. Among the broadleaved species, low leaf wettability, low stomatal density and leaf hairiness increased particle capture. Moderate soil drought tended to increase particle capture efficiency of P. sylvestris. PMID:23735814

  18. The characteristics of the thermal energy storage in a two-compartment water tank

    Microsoft Academic Search

    Sui Lin; C. C. K. Kwok; J. C. Y. Wang

    1984-01-01

    A water storage tank consisting of two equal compartments of 35.56 cm i.d. and 50.8 cm height, used in a solar water-heating system, was designed and manufactured. The lower compartment, which contained the cold water inlet, was in a loop with a solar energy collector. The upper compartment, from which hot water could be drawn, was connected to the top

  19. Spatial variation in density, mean size and physiological condition of the holarctic amphipod Diporeia spp. in Lake Michigan

    Microsoft Academic Search

    Thomas F. Nalepa; David J. Hartson; Jennifer Buchanan; Joann F. Cavaletto; Gregory A. Lang; Stephen J. Lozano

    2000-01-01

    SUMMARY 1. We examined spatial patterns in population characteristics (density, biomass, mean body length) and physiological condition (lipid content, length-weight) of the amphipod Diporeia spp. in Lake Michigan by collecting samples at up to 85 sites in late summer 1994 and 1995. Variables were examined relative to water depth and three lake regions: south, central and north. Most major river

  20. Leaf gas exchange and water relation characteristics of field quinoa ( Chenopodium quinoa Willd.) during soil drying

    Microsoft Academic Search

    C. R Jensen; S.-E Jacobsen; M. N Andersen; N Núñez; S. D Andersen; L Rasmussen; V. O Mogensen

    2000-01-01

    The effects of soil drying on leaf water relations and gas exchange were studied in quinoa grown in pots with sandy soil and in lysimeter plots with sandy loam in the field. Midday values of leaf water potential (?l), leaf osmotic potential (??), relative water content (RWC), leaf conductance (gl), light saturated net photosynthesis (Asat), and specific leaf area (SLA)

  1. Global modeling of land water and energy balances. Part II: Land-characteristic contributions to spatial variability

    USGS Publications Warehouse

    Milly, P.C.D.; Shmakin, A.B.

    2002-01-01

    Land water and energy balances vary around the globe because of variations in amount and temporal distribution of water and energy supplies and because of variations in land characteristics. The former control (water and energy supplies) explains much more variance in water and energy balances than the latter (land characteristics). A largely untested hypothesis underlying most global models of land water and energy balance is the assumption that parameter values based on estimated geographic distributions of soil and vegetation characteristics improve the performance of the models relative to the use of globally constant land parameters. This hypothesis is tested here through an evaluation of the improvement in performance of one land model associated with the introduction of geographic information on land characteristics. The capability of the model to reproduce annual runoff ratios of large river basins, with and without information on the global distribution of albedo, rooting depth, and stomatal resistance, is assessed. To allow a fair comparison, the model is calibrated in both cases by adjusting globally constant scale factors for snow-free albedo, non-water-stressed bulk stomatal resistance, and critical root density (which is used to determine effective root-zone depth). The test is made in stand-alone mode, that is, using prescribed radiative and atmospheric forcing. Model performance is evaluated by comparing modeled runoff ratios with observed runoff ratios for a set of basins where precipitation biases have been shown to be minimal. The withholding of information on global variations in these parameters leads to a significant degradation of the capability of the model to simulate the annual runoff ratio. An additional set of optimization experiments, in which the parameters are examined individually, reveals that the stomatal resistance is, by far, the parameter among these three whose spatial variations add the most predictive power to the model in stand-alone mode. Further single-parameter experiments with surface roughness length, available water capacity, thermal conductivity, and thermal diffusivity show very little sensitivity to estimated global variations in these parameters. Finally, it is found that even the constant-parameter model performance exceeds that of the Budyko and generalized Turc-Pike water-balance equations, suggesting that the model benefits also from information on the geographic variability of the temporal structure of forcing.

  2. Pioneering in gravitational physiology

    NASA Technical Reports Server (NTRS)

    Soffen, G. A.

    1983-01-01

    Gravity affects biology at almost all levels above that of the cell organelle. Attention is presently given to progress made in the understanding of gravitational effects through studies employing centrifuges, clinostats, inverted preparations, linear devices, water immersion, free fall, and short- and long-term spaceflight. The cardiovascular changes which cause malaise and illness during the first few days of extended space missions are the direct result of fluid translocation from the lower extremities. Upon reentry, there is hypovolumnia and a cardiovascular deconditioning that can include tachycardia, changes in arterial blood pressure, narrow pulse pressure, and syncope. Attention is also given to NASA's gravitational physiology reseach program.

  3. Characteristics of disinfection by-products reduction in the processes of drinking water treatment system using Nakdong river water

    Microsoft Academic Search

    Young-Jin Kim; Kil-Soo Hyun

    2012-01-01

    In this study, batch and continuous experiments were conducted to investigate the influential factors on the distribution and formation of aldehydes, bromate and bromide in Nakdong river water and to investigate the behaviour of disinfection by-products (DBPs) in the processes of drinking water treatment system. The mean influent concentrations were 3.1?mg\\/L (2.4–3.9?mg\\/L) for dissolved organic carbon (DOC), 57.6 ug\\/L (42.0–85.7

  4. Characteristics of the water vapour transport over the Mackenzie river basin during the 1994\\/95 water year

    Microsoft Academic Search

    Jinliang Liu; Ronald E. Stewart

    2002-01-01

    The National Centers for Environmental Prediction\\/National Center for Atmospheric Research (NCEP\\/NCAR) reanalysis data were used to calculate the moisture flux convergence over the Mackenzie River basin (MRB) for a 10?year period from 1987 to 1996. The analysis of these results indicates that the 1994\\/95 water year was associated with the least amount of water vapour transport into the MRB over

  5. Theoretical Study on Dynamic Characteristics of Energy Efficiency Standard Value of Ground Water Heat Pump Air-conditioning System

    NASA Astrophysics Data System (ADS)

    Peng, Yi; Wang, Zhiwei; Zhang, Zhonghe; Cao, Wei; Li, Peng

    The energy efficiency standard value of the ground water heat pump air-conditioning system is the benchmar parameter for energy saving operation and control of the system. According to each loop's process energy consumption of the system, the control equation of energy efficiency standard value of the water source side loop, heat pump unit and user side loop is established respectively. The dynamic characteristics of the standard value variation with the air-conditioning hourly heating and cooling load is revealed, and the energy efficiency standard value of each loop can be also obtained, and the qualitative sensitivity analysis of the dynamic characteristics in each subsystem is carried out. For system energy saving operation and control, the basic data and theoretical guidance can be provided.

  6. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-05-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15?mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20?mg/l) was broader than that of acid-soluble chitosan (4-8?mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

  7. Effect of soil water changes on photosynthetic characteristics of Taxodium distichum seedlings in the hydro-fluctuation belt of the Three Gorges Reservoir area

    Microsoft Academic Search

    Changxiao Li; Zhangcheng Zhong; Yun Liu

    2006-01-01

    Four different kinds of water treatment were applied to examine the photosynthetic characteristics of baldcypress (Taxodium distichum) seedlings in the hydro-fluctuation belt of the Three Gorges Reservoir area. The aim was to shed light on the physio-ecological\\u000a adaptation of this species to changing water levels for revegetation purposes. The water treatments were normal growth water\\u000a condition (CK), light drought water

  8. Physiological basis of genetic variation in leaf photosynthesis among rice (Oryza sativa L.) introgression lines under drought and well-watered conditions

    PubMed Central

    Yin, Xinyou

    2012-01-01

    To understand the physiological basis of genetic variation and resulting quantitative trait loci (QTLs) for photosynthesis in a rice (Oryza sativa L.) introgression line population, 13 lines were studied under drought and well-watered conditions, at flowering and grain filling. Simultaneous gas exchange and chlorophyll fluorescence measurements were conducted at various levels of incident irradiance and ambient CO2 to estimate parameters of a model that dissects photosynthesis into stomatal conductance (g s), mesophyll conductance (g m), electron transport capacity (J max), and Rubisco carboxylation capacity (V cmax). Significant genetic variation in these parameters was found, although drought and leaf age accounted for larger proportions of the total variation. Genetic variation in light-saturated photosynthesis and transpiration efficiency (TE) were mainly associated with variation in g s and g m. One previously mapped major QTL of photosynthesis was associated with variation in g s and g m, but also in J max and V cmax at flowering. Thus, g s and g m, which were demonstrated in the literature to be responsible for environmental variation in photosynthesis, were found also to be associated with genetic variation in photosynthesis. Furthermore, relationships between these parameters and leaf nitrogen or dry matter per unit area, which were previously found across environmental treatments, were shown to be valid for variation across genotypes. Finally, the extent to which photosynthesis rate and TE can be improved was evaluated. Virtual ideotypes were estimated to have 17.0% higher photosynthesis and 25.1% higher TE compared with the best genotype investigated. This analysis using introgression lines highlights possibilities of improving both photosynthesis and TE within the same genetic background. PMID:22888131

  9. Physiological basis of genetic variation in leaf photosynthesis among rice (Oryza sativa L.) introgression lines under drought and well-watered conditions.

    PubMed

    Gu, Junfei; Yin, Xinyou; Stomph, Tjeerd-Jan; Wang, Huaqi; Struik, Paul C

    2012-09-01

    To understand the physiological basis of genetic variation and resulting quantitative trait loci (QTLs) for photosynthesis in a rice (Oryza sativa L.) introgression line population, 13 lines were studied under drought and well-watered conditions, at flowering and grain filling. Simultaneous gas exchange and chlorophyll fluorescence measurements were conducted at various levels of incident irradiance and ambient CO(2) to estimate parameters of a model that dissects photosynthesis into stomatal conductance (g(s)), mesophyll conductance (g(m)), electron transport capacity (J(max)), and Rubisco carboxylation capacity (V(cmax)). Significant genetic variation in these parameters was found, although drought and leaf age accounted for larger proportions of the total variation. Genetic variation in light-saturated photosynthesis and transpiration efficiency (TE) were mainly associated with variation in g(s) and g(m). One previously mapped major QTL of photosynthesis was associated with variation in g(s) and g(m), but also in J(max) and V(cmax) at flowering. Thus, g(s) and g(m), which were demonstrated in the literature to be responsible for environmental variation in photosynthesis, were found also to be associated with genetic variation in photosynthesis. Furthermore, relationships between these parameters and leaf nitrogen or dry matter per unit area, which were previously found across environmental treatments, were shown to be valid for variation across genotypes. Finally, the extent to which photosynthesis rate and TE can be improved was evaluated. Virtual ideotypes were estimated to have 17.0% higher photosynthesis and 25.1% higher TE compared with the best genotype investigated. This analysis using introgression lines highlights possibilities of improving both photosynthesis and TE within the same genetic background. PMID:22888131

  10. Experimental and analytical study of stability characteristics of natural circulation boiling water reactors during startup transient

    NASA Astrophysics Data System (ADS)

    Woo, Kyoungsuk

    Two-phase natural circulation loops are unstable at low pressure operating conditions. New reactor design relying on natural circulation for both normal and abnormal core cooling is susceptible to different types of flow instabilities. In contrast to forced circulation boiling water reactor (BWR), natural circulation BWR is started up without recirculation pumps. The tall chimney placed on the top of the core makes the system susceptible to flashing during low pressure start-up. In addition, the considerable saturation temperature variation may induce complicated dynamic behavior driven by thermal non-equilibrium between the liquid and steam. The thermal-hydraulic problems in two-phase natural circulation systems at low pressure and low power conditions are investigated through experimental methods. Fuel heat conduction, neutron kinetics, flow kinematics, energetics and dynamics that govern the flow behavior at low pressure, are formulated. A dimensionless analysis is introduced to obtain governing dimensionless groups which are groundwork of the system scaling. Based on the robust scaling method and start-up procedures of a typical natural circulation BWR, the simulation strategies for the transient with and without void reactivity feedback is developed. Three different heat-up rates are applied to the transient simulations to study characteristics of the stability during the start-up. Reducing heat-up rate leads to increase in the period of flashing-induced density wave oscillation and decrease in the system pressurization rate. However, reducing the heat-up rate is unable to completely prevent flashing-induced oscillations. Five characteristic regions of stability are discovered at low pressure conditions. They are stable single-phase, flashing near the separator, intermittent oscillation, sinusoidal oscillation and low subcooling stable regions. Stability maps were acquired for system pressures ranging 100 kPa to 400 kPa. According to experimental investigation, the flow becomes stable below a certain heat flux regardless of the inlet subcooling at the core and system pressure. At higher heat flux, unstable phenomena were indentified within a certain range of inlet subcooling. The unstable region diminishes as the system pressure increases. In natural circulation BWRs, the significant gravitational pressure drop over the tall chimney section induces a Type-I instability. The Type-I instability becomes especially important during low power and pressure conditions during reactor start-up. Under these circumstances the effect of pressure variations on the saturation enthalpy becomes significant. An experimental study shows that the flashing phenomenon in the adiabatic chimney section is dominant during the start-up of a natural circulation BWR. Since flashing occurs outside the core, nuclear feedback effects on the stability are small. Furthermore, the thermal-hydraulic oscillation period is much longer than power fluctuation period caused by void reactivity feedback. In the natural circulation system increasing the inlet restriction reduces the natural circulation flow rate, shifting the unstable region to higher inlet subcooling.

  11. Self-compensating characteristic of steam–water mixture at low mass velocity in vertical upward parallel internally ribbed tubes

    Microsoft Academic Search

    Xiaojing Zhu; Qincheng Bi; Qianhua Su; Dong Yang; Jianguo Wang; Gang Wu; Shuiqing Yu

    2010-01-01

    This paper presents an experimental investigation on Self-Compensating Characteristic (SCC) in vertical upward parallel tubes with low mass velocity of steam–water two-phase mixture. A physical model was built up using parallel internally ribbed tubes. A method called Differential Pressure Substitute was used to measure two-phase flow parameters. The results indicated that the SCC of vertical upward parallel tubes is caused

  12. Ingested arsenic, characteristics of well water consumption and risk of different histological types of lung cancer in northeastern Taiwan

    Microsoft Academic Search

    Chi-Ling Chen; Hung-Yi Chiou; Ling-I. Hsu; Yu-Mei Hsueh; Meei-Maan Wu; Chien-Jen Chen

    2010-01-01

    Our previous study combining two arseniasis-endemic areas in Taiwan confirmed a dose–response association of lung cancer and arsenic exposure. We conducted current analysis to elucidate the dose–response relationship in lower exposure level, and to evaluate whether the association differs in different histological types. In addition, whether specific characteristics of well water consumptions increased lung cancer risk was examined in order

  13. Characteristics of spent fuel from plutonium disposition reactors. Volume 3: A Westinghouse pressurized-water reactor design

    Microsoft Academic Search

    1997-01-01

    This diskette contains files associated with the operation of the SCALE system codes discussed in the accompanying report ORNL\\/TM-- 13170\\/V3 `Characteristics of Spent Fuel from Plutonium Disposition Reactors Vol. 3: Pressurized-Water Reactor Design`. The SAS2H code sequence was used to simulate the burnup of the fuel assemblies studied. A description of each file is found in Appendix B of the

  14. INFLUENCE OF SOLVENT AND SORBENT CHARACTERISTICS ON DISTRIBUTION OF PENTACHLOROPHENOL IN OCTANOL-WATER AND SOIL-WATER SYSTEMS

    EPA Science Inventory

    Sorbent and solvent characteristics influencing sorption of pentachlorophenol (PCP) were investigated. nalysis of aqueous sorption data for several sorbents over a broad pH range suggested hydrophobic sorption of neutral PCP predominates at pH7, sorption of the pentachlo...

  15. INFLUENCE OF SOLVENT AND SORBENT CHARACTERISTICS ON DISTRIBUTION OF PENTACHLOROPHENOL IN OCTANOL-WATER AND SOIL-WATER SYSTEMS

    EPA Science Inventory

    Sorbent and solvent characteristics influencing sorption of pentachlorophenol (PCP) were investigated. Analysis of aqueous sorption data for several sorbents over a broad pH range suggested hydrophobic sorption of neutral PCP predominates at pH 7. At pH > 7, sorption of the penta...

  16. Physiological Daily Inhalation Rates for Free-Living Individuals Aged 1 Month to 96 Years, Using Data from Doubly Labeled Water Measurements: A Proposal for Air Quality Criteria, Standard Calculations and Health Risk Assessment

    Microsoft Academic Search

    Pierre Brochu; Jean-François Ducré-Robitaille; Jules Brodeur

    2006-01-01

    Reported disappearance rates of oral doses of doubly labeled water (H2O and H2 O) in urine, monitored by gas-isotope-ratio mass spectrometry for an aggregate period of over 30,000 days and completed with indirect calorimetry and nutritional balance measurements, have been used to determine physiological daily inhalation rates for 2210 individuals aged 3 weeks to 96 years. Rates in m\\/kg-day for

  17. Changes in Mediterranean circulation and water characteristics due to restriction of the Atlantic connection: a high-resolution ocean model

    NASA Astrophysics Data System (ADS)

    Topper, R. P. M.; Meijer, P. Th.

    2015-02-01

    A high-resolution parallel ocean model is set up to examine how the sill depth of the Atlantic connection affects circulation and water characteristics in the Mediterranean Basin. An analysis of the model performance, comparing model results with observations of the present-day Mediterranean, demonstrates its ability to reproduce observed water characteristics and circulation (including deep water formation). A series of experiments with different sill depths in the Atlantic-Mediterranean connection is used to assess the sensitivity of Mediterranean circulation and water characteristics to sill depth. Basin-averaged water salinity and, to a lesser degree, temperature rise when the sill depth is shallower and exchange with the Atlantic is lower. Lateral and interbasinal differences in the Mediterranean are, however, largely unchanged. The strength of the upper overturning cell in the western basin is proportional to the magnitude of the exchange with the Atlantic, and hence to sill depth. Overturning in the eastern basin and deep water formation in both basins, on the contrary, are little affected by the sill depth. The model results are used to interpret the sedimentary record of the Late Miocene preceding and during the Messinian Salinity Crisis. In the western basin, a correlation exists between sill depth and rate of refreshment of deep water. On the other hand, because sill depth has little effect on the overturning and deep water formation in the eastern basin, the model results do not support the notion that restriction of the Atlantic-Mediterranean connection may cause lower oxygenation of deep water in the eastern basin. However, this discrepancy may be due to simplifications in the surface forcing and the use of a bathymetry different from that in the Late Miocene. We also tentatively conclude that blocked outflow, as found in experiments with a sill depth ≤10 m, is a plausible scenario for the second stage of the Messinian Salinity Crisis during which halite was rapidly accumulated in the Mediterranean. With the model setup and experiments, a basis has been established for future work on the sensitivity of Mediterranean circulation to changes in (palaeo-)bathymetry and external forcings.

  18. Relation of trihalomethane-formation potential to water-quality and physical characteristics of small water-supply lakes, eastern Kansas

    USGS Publications Warehouse

    Pope, L.M.; Arruda, J.A.; Fromm, C.H.

    1988-01-01

    The formation of carcinogenic trihalomethanes during the treatment of public surface water supplies has become a potentially serious problem. The U. S. Geological Survey, in cooperation with the Kansas Department of Health and Environment , investigated the potential for trihalomethane formation in water from 15 small, public water supply lakes in eastern Kansas from April 1984 through April 1986 in order to define the principal factors that affect or control the potential for trihalomethane formation during the water treatment process. Relations of mean concentrations of trihalomethane-formation potential to selected water quality and lake and watershed physical characteristics were investigated using correlation and regression analysis. Statistically significant, direct relations were developed between trihalomethanes produced in unfiltered and filtered lake water and mean concentrations of total and dissolved organic carbon. Correlation coefficients for these relations ranged from 0.86 to 0.93. Mean values of maximum depth of lake were shown to have statistically significant inverse relations to mean concentrations of trihalomethane-formation potential and total and dissolved organic carbon. Correlation coefficients for these relations ranged from -0.76 to -0.81. (USGS)

  19. 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.

    PubMed

    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?

  20. 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

    NASA Astrophysics Data System (ADS)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2014-08-01

    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 < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P < 0.05). High 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 < 0.05). White and brown-white patched cows had significantly longer (P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower (P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different (P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  1. 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

    NASA Astrophysics Data System (ADS)

    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 < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms ( P < 0.05). High 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 < 0.05). White and brown-white patched cows had significantly longer ( P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower ( P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different ( P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  2. Characteristics of ? 18 O in precipitation over Eastern Monsoon China and the water vapor sources

    Microsoft Academic Search

    JianRong Liu; XianFang Song; GuoFu Yuan; XiaoMin Sun; Xin Liu; ShiQin Wang

    2010-01-01

    Monsoon circulation is an important carrier of water vapor transport, and it impacts the precipitation of the monsoonal regions\\u000a through the constraints and controls of large-scale water vapor transport and distributions as well as the water vapor balance.\\u000a An overall research on stable Hydrogen and Oxygen isotopes in precipitation over Eastern Monsoon China could benefit a comprehensive\\u000a understanding of the

  3. Modeling the performance characteristics of water-cooled air-conditioners

    Microsoft Academic Search

    W. L. Lee; Hua Chen; F. W. H. Yik

    2008-01-01

    Water-cooled air-conditioning systems (WACS) are widely used in the commercial sector for energy efficiency, but not in the domestic sector. It has been found that there are no mathematical models and energy simulation programs to enable detailed investigation and evaluation into the energy performance of water-cooled air-conditioners. To improve the applicability of water-cooled air-conditioners in the domestic sector, the development

  4. Characteristics of widespread pyroclastic deposits formed by the interaction of silicic magma and water

    Microsoft Academic Search

    S. Self; R. S. J. Sparks

    1978-01-01

    We have recognized a type of pyroclastic deposit formed by the interaction of water and silicic magma during explosive eruptions.\\u000a These deposits have a widespread dispersal, similar to plinian tephra, but the overall grain size is much tiner. Several deposits\\u000a studied can be associated with caldera lakes or sea water and water\\/magma interaction is proposed to account for the fine

  5. Water use characteristics of black mangrove (Avicennia germinans) communities along an ecotone with marsh at a northern geographical limit

    USGS Publications Warehouse

    Krauss, Ken W.; McKee, Karen L.; Hester, Mark W.

    2014-01-01

    Mangroves are expanding into warm temperate-zone salt marsh communities in several locations globally. Although scientists have discovered that expansion might have modest effects on ecosystem functioning, water use characteristics have not been assessed relative to this transition. We measured early growing season sapflow (Js) and leaf transpiration (Tr) in Avicennia germinans at a latitudinal limit along the northern Gulf of Mexico (Louisiana, United States) under both flooded and drained states and used these data to scale vegetation water use responses in comparison with Spartina alterniflora. We discovered strong convergence when using either Js or Tr for determining individual tree water use, indicating tight connection between transpiration and xylem water movement in small Avicennia trees. When Tr data were combined with leaf area indices for the region with the use of three separate approaches, we determined that Avicennia stands use approximately 1·0–1·3?mm?d–1 less water than Spartina marsh. Differences were only significant with the use of two of the three approaches, but are suggestive of net conservation of water as Avicennia expands into Spartina marshes at this location. Average Js for Avicennia trees was not influenced by flooding, but maximum Js was greater when sites were flooded. Avicennia and Spartina closest to open water (shoreline) used more water than interior locations of the same assemblages by an average of 1·3?mm?d?1. Lower water use by Avicennia may indicate a greater overall resilience to drought relative to Spartina, such that aperiodic drought may interact with warmer winter temperatures to facilitate expansion of Avicennia in some years.

  6. [Water impounding characteristics of bamboo-shaped rainwater harvesting ditch in the hilly loess region].

    PubMed

    Lin, Jun; Wang, You-Ke; Wei, Xin-Dong; Xiao, Sen; Zhang, Xue

    2013-12-01

    Bamboo-shaped rainwater harvesting ditch (BRHD) is a new water harvesting and application technology being promoted in the hilly loess region of North Shannxi Province. This paper measured the soil moisture condition and water storage capacity of BRHDs filled with straw, branch or gravel through field and simulated rainfall experiments to evaluate the water holding and absorption capacity of different BRHD fillers. From May to October, the water storage of BRHDs showed a decrease trend at first and then increased in field experiment. The water storage depths within 30-200 cm profile of branch ditch (BD), gravel ditch (GD) and straw ditch (SD) were 186.76, 177.23 and 169.26 mm in May, respectively, and increased by 14.24, 20.28 and 21.23 mm in October, respectively. In contrast, the water storage depth of the level bench was reduced by 6.52 mm in October from 185.76 mm in May. The soil water restoration depth was different between BRHDs with different fillers and the level bench within 30-200 cm profile in October. The SD and BD had the deepest restoration depth (140 cm), followed by GD (110 cm), and the level bench was the minimum (80 cm). Through rainfall simulation experiment, the amount of water intercepted by BRHD was in the order of SD (99.5 L) > GD (91 L) > BD (71.5 L). The water-holding rate of straw and branch showed logarithmic function with soaking time, while the water-absorption rate followed a power function. Moreover, there was a negative logarithm correlation between water-holding rate and water-absorption rate. Straw showed a better water holding and absorption capacity than branch. Gravel had a weak water holding and absorption capacity which was almost not changed during soaking, while it displayed a negative liner correlation between water holding rate and absorption rate. The three kinds of BRHDs could be applied in the hilly loess region, and that filled with straw would exhibit the best capacity of water interception and holding. PMID:24697054

  7. A new approach for the in situ determination of soil water retention characteristics for shallow groundwater systems

    NASA Astrophysics Data System (ADS)

    Dettmann, Ullrich; Bechtold, Michel

    2015-04-01

    Obtaining representative effective hydraulic properties for the pedon to field scale as input for models is a major challenge in hydrology. Hydraulic properties are often determined by laboratory measurements on small soil cores. Due to the high small-scale variability, many samples are needed to obtain representative values, which is time consuming and costly. Here, we present a new approach which is focused on the in situ determination of the soil water retention characteristics that is applicable to shallow groundwater systems. The method integrates over small-scale heterogeneity (appr. several meters) and uses only precipitation and water-level data. Our approach is built on two assumptions: i) for shallow groundwater systems (with water table depths of appr. < 0.5 to 1 m) , e.g. wetlands, with medium- to high conductive soils the soil moisture profile is close to hydrostatic equilibrium before and after rain events (Dettmann et al., 2014, J Hydrol, 515, 103-115) and ii) over short time periods lateral fluxes into and out of the system are negligible. Given these assumptions, the height of a water level rise after a precipitation event only depends on the soil water retention characteristics, the precipitation amount of the event and the initial water table depths. We use this dependency, to determine van Genuchten-parameters by Bayesian inversion. The applicability of the method is proved by synthetic data. Water retention characteristics are very well-constrained for the low suction range. At high suctions uncertainties strongly increase as this suction range is not covered by the approach. With real field data, some phenomena make an accurate determination more difficult. Wetlands are typically characterized by a distinct microrelief leading to partly inundated areas around a monitoring well in dependence of the water level. For field application, we thus developed a model that takes into account the microrelief by assuming frequency distributions. Furthermore, preferential flow phenomena were accounted for by waiting for the system to equilibrate a few hours after the rain events. The inversely-determined parameters are compared against laboratory data.

  8. Chemical Characteristics of Water-Soluble Ions in Particulate Matter in Three Metropolitan Areas in the North China Plain

    PubMed Central

    Dao, Xu; Wang, Zhen; Lv, Yibing; Teng, Enjiang; Zhang, Linlin; Wang, Chao

    2014-01-01

    PM2.5 and PM10 samples were collected simultaneously in each season in Beijing, Tianjin and Shijiazhuang to identify the characteristics of water-soluble ion compositions in the North China Plain. The water-soluble ions displayed significant seasonal variation. The dominant ions were NO3?, SO42?, NH4+ and Cl?, accounting for more than 90% and 86% to the mass of total water-soluble ions in PM2.5 and PM10, respectively. The anion/cation ratio indicated that the ion acidity of each city varied both between sites and seasonally. Over 50% of the ion species were enriched in small particles ?1 µm in diameter. The [NO3?]/[SO42?] ratio indicated that vehicles accounted for the majority of the particulate pollution in Beijing. Shijiazhuang, a city highly reliant on coal combustion, had a higher SO42? concentration. PMID:25437210

  9. Effects of Water Quality and Orthophosphate on Surface Characteristics of Cu Corrosion in Drinking Water using Atomic Force Microscopy

    EPA Science Inventory

    Since the passage of the Lead and Copper Rule (LCR) in 1991, researchers have examined the effects of water chemistry on the solubility of copper to establish best approaches for reducing copper levels. Despite recent developments, important gaps still exist regarding copper cor...

  10. Turbulent heat transfer and pressure drop characteristics of dilute water based Al2O3-Cu hybrid nanofluids.

    PubMed

    Suresh, S; Venkitaraj, K P; Hameed, M Shahul; Sarangan, J

    2014-03-01

    A study on fully developed turbulent convective heat transfer and pressure drop characteristics of Al2O3-Cu/water hybrid nanofluid flowing through a uniformly heated circular tube is presented in this paper. For this, Al2O3-Cu nanocomposite powder was synthesized in a thermo chemical route using hydrogen reduction technique and dispersed the hybrid nano powder in deionised water to form a stable hybrid nanofluid of 0.1% volume concentration. The prepared powder was characterized by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) to confirm the chemical composition, determine the particle size and study the surface morphology. Stability of the nanofluid was ensured by pH and zeta potential measurements. The average heat transfer enhancement for Al2O3-Cu/water hybrid nanofluid is 8.02% when compared to pure water. The experimental results also showed that 0.1% Al2O3-Cu/water hybrid nanofluids have slightly higher friction factor compared to 0.1% Al2O3/water nanofluid. The empirical correlations proposed for Nusselt number and friction factor were well agreed with the experimental data. PMID:24745264

  11. Palms versus trees: water use characteristics of native fruit-bearing plant species in the Central Amazon

    NASA Astrophysics Data System (ADS)

    Kunert, N.; Barros, P.; Higuchi, N.

    2012-12-01

    Native fruiting plants are widely cultivated in the Amazon but only little information on their water use characteristics can be found in the literature. Due to the growing local consumption and the increasing popularity for new "exotic" fruits all over Brazil and worldwide, additional new plantations cultivating such fruit-bearing species might be established in the Amazon in the future. These new plantations will affect the water table of the cultivated areas, however, the impact of these changes on the regional hydrology are not known. We, therefore, decided to study plant water use characteristics of two native fruit plants commonly occurring in the Amazon region, a tree species (Cupuaçu, Theobroma grandiflorum, (Willd. ex Spreng.) Schum., Malvaceae) and a palm species (Açai, Euterpe oleraceae Mart., Arecaceae). This study was conducted in a fruit plantation close to the city of Manaus, in the Central Amazon, Brazil. The objectives of our study were 1) to compare variables controlling plant water use and 2) to identify differences in water use between woody monocot and dicot plant species. We chose three representative individuals with well-sun-exposed crowns for each species, which were equipped with Granier-type thermal dissipation probes to measure sap flux density continuously for six weeks from August 1st 2011 until September 6th 2011. We used a simple sap flux model with two environmental variables, photosynthetic photon flux density and vapor pressure deficit, to compare sap flux densities between species. We achieved a good model fit and modeled sap flux densities corresponded very well with the actual measured values. No significant differences among species in sap flux densities were indicated by the model. Overall, palms had a 3.5 fold higher water consumption compared to trees with similar diameter. Water use scaled independent from species with the size of the conductive xylem area (r2 = 0.85), so that the higher water use of the palms was largely explained by higher conductivity of the xylem cross section area. Palms transpired a mean of 1.67 mm m-2 of water per unit crown projection area per day, whereas trees transpired only 0.30 mm m-2 per day, resulting in a 5.6 times lower transpiration rate. We conclude that changes in the water table due to land use change are predictable and highly depending on the species planted in the area with altered land use.

  12. Fractals in physiology and medicine

    NASA Technical Reports Server (NTRS)

    Goldberger, Ary L.; West, Bruce J.

    1987-01-01

    The paper demonstrates how the nonlinear concepts of fractals, as applied in physiology and medicine, can provide an insight into the organization of such complex structures as the tracheobronchial tree and heart, as well as into the dynamics of healthy physiological variability. Particular attention is given to the characteristics of computer-generated fractal lungs and heart and to fractal pathologies in these organs. It is shown that alterations in fractal scaling may underlie a number of pathophysiological disturbances, including sudden cardiac death syndromes.

  13. Long-term characteristics of XLPE insulated cable installed in water

    Microsoft Academic Search

    Teruo Kaneko; Hironobu Ohno; Takeshi Goto; Shoshi Katakai; H. Muto

    1994-01-01

    The long-term voltage characteristics (V-t characteristics) have been evaluated for XLPE cables having 6-mm insulation thickness that were energized while immersed and the causes of cable breakdown have been elucidated by means of residual breakdown tests conducted by the pre-interruption method. The life index n was found to increase with decreases in the intensity of the applied field. Among causes

  14. COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING

    EPA Science Inventory

    Discrete coldwater patches within the surface waters of summer-warm streams afford potential thermal refuge for coldwater fishes during periods of heat stress. This analysis focused on reach-scale heterogeneity in water temperatures as influenced by local influx of cooler subsur...

  15. Occurrence and Removal Characteristics of Phthalate Esters from Typical Water Sources in Northeast China

    PubMed Central

    Liu, Yu; Chen, Zhonglin; Shen, Jimin

    2013-01-01

    The presence of phthalate esters (PAEs) in the environment has gained a considerable attention due to their potential impacts on public health. This study reports the first data on the occurrence of 15 PAEs in the water near the Mopanshan Reservoir—the new and important water source of Harbin city in Northeast China. As drinking water is a major source for human exposure to PAEs, the fate of target PAEs in the two waterworks (Mopanshan Waterworks and Seven Waterworks) was also analyzed. The results demonstrated that the total concentrations of 15 PAEs in the water near the Mopanshan Reservoir were relatively moderate, ranging from 355.8 to 9226.5?ng/L, with the mean value of 2943.1?ng/L. DBP and DEHP dominated the PAE concentrations, which ranged from 52.5 to 4498.2?ng/L and 128.9 to 6570.9?ng/L, respectively. The occurrence and concentrations of these compounds were heavily spatially dependent. Meanwhile, the results on the waterworks samples suggested no significant differences in PAE levels with the input of the raw waters. Without effective and stable removal of PAEs after the conventional drinking water treatment in the waterworks (25.8% to 76.5%), the risks posed by PAEs through drinking water ingestion were still existing, which should be paid special attention to the source control in the Mopanshan Reservoir and some advanced treatment processes for drinking water supplies. PMID:23577281

  16. Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

    Microsoft Academic Search

    S. A. Terpugova; V. V. Polkin; M. V. Panchenko; L. P. Golobokova; V. S. Kozlov; V. P. Shmargunov; V. P. Shevchenko; A. P. Lisitzin

    2009-01-01

    The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV \\

  17. 14 CFR 25.239 - Spray characteristics, control, and stability on water.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...established in accordance with § 25.231; (2) In wind and cross-wind velocities, water currents, and associated waves and swells that may reasonably be expected in operation on water; (3) At speeds that may reasonably be expected in operation on...

  18. 14 CFR 25.239 - Spray characteristics, control, and stability on water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...established in accordance with § 25.231; (2) In wind and cross-wind velocities, water currents, and associated waves and swells that may reasonably be expected in operation on water; (3) At speeds that may reasonably be expected in operation on...

  19. 14 CFR 25.239 - Spray characteristics, control, and stability on water.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...established in accordance with § 25.231; (2) In wind and cross-wind velocities, water currents, and associated waves and swells that may reasonably be expected in operation on water; (3) At speeds that may reasonably be expected in operation on...

  20. 14 CFR 25.239 - Spray characteristics, control, and stability on water.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...established in accordance with § 25.231; (2) In wind and cross-wind velocities, water currents, and associated waves and swells that may reasonably be expected in operation on water; (3) At speeds that may reasonably be expected in operation on...

  1. 14 CFR 25.239 - Spray characteristics, control, and stability on water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...established in accordance with § 25.231; (2) In wind and cross-wind velocities, water currents, and associated waves and swells that may reasonably be expected in operation on water; (3) At speeds that may reasonably be expected in operation on...

  2. Water Consumption Characteristics and Water Use Efficiency of Winter Wheat under Long-Term Nitrogen Fertilization Regimes in Northwest China

    PubMed Central

    Zhong, Yangquanwei; Shangguan, Zhouping

    2014-01-01

    Water shortage and nitrogen (N) deficiency are the key factors limiting agricultural production in arid and semi-arid regions, and increasing agricultural productivity under rain-fed conditions often requires N management strategies. A field experiment on winter wheat (Triticum aestivum L.) was begun in 2004 to investigate effects of long-term N fertilization in the traditional pattern used for wheat in China. Using data collected over three consecutive years, commencing five years after the experiment began, the effects of N fertilization on wheat yield, evapotranspiration (ET) and water use efficiency (WUE, i.e. the ratio of grain yield to total ET in the crop growing season) were examined. In 2010, 2011 and 2012, N increased the yield of wheat cultivar Zhengmai No. 9023 by up to 61.1, 117.9 and 34.7%, respectively, and correspondingly in cultivar Changhan No. 58 by 58.4, 100.8 and 51.7%. N-applied treatments increased water consumption in different layers of 0–200 cm of soil and thus ET was significantly higher in N-applied than in non-N treatments. WUE was in the range of 1.0–2.09 kg/m3 for 2010, 2011 and 2012. N fertilization significantly increased WUE in 2010 and 2011, but not in 2012. The results indicated the following: (1) in this dryland farming system, increased N fertilization could raise wheat yield, and the drought-tolerant Changhan No. 58 showed a yield advantage in drought environments with high N fertilizer rates; (2) N application affected water consumption in different soil layers, and promoted wheat absorbing deeper soil water and so increased utilization of soil water; and (3) comprehensive consideration of yield and WUE of wheat indicated that the N rate of 270 kg/ha for Changhan No. 58 was better to avoid the risk of reduced production reduction due to lack of precipitation; however, under conditions of better soil moisture, the N rate of 180 kg/ha was more economic. PMID:24905909

  3. Abundance and characteristics of the recreational water quality indicator bacteria Escherichia coli and enterococci in gull faeces

    USGS Publications Warehouse

    Fogarty, L.R.; Haack, S.K.; Wolcott, M.J.; Whitman, R.L.

    2003-01-01

    Aims: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal indicator bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. Methods and Results: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (Vitek?? GNI+) and enterococci (API?? rapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at ???85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus API?? profiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. Conclusions: Gull faeces could be a major contributor of E. coli (105-109 CFU g-1) and enterococci (104-108 CFU g-1) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. Significance and Impact of the Study: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.

  4. Teaching Stress Physiology Using Zebrafish ("Danio Rerio")

    ERIC Educational Resources Information Center

    Cooper, Michael; Dhawale, Shree; Mustafa, Ahmed

    2009-01-01

    A straightforward and inexpensive laboratory experiment is presented that investigates the physiological stress response of zebrafish after a 5 degree C increase in water temperature. This experiment is designed for an undergraduate physiology lab and allows students to learn the scientific method and relevant laboratory techniques without causing…

  5. Effects of water-control structures on hydrologic and water-quality characteristics in selected agricultural drainage canals in eastern North Carolina

    USGS Publications Warehouse

    Treece, M.W., Jr.; Jaynes, M.L.

    1994-01-01

    November of water into and out of tidally affected canals in eastern North Carolina was documented before and after the installation of water-control structures. Water levels in five of the canals downstream from the water-control structures were controlled primarily by water-level fluctuations in estuarine receiving waters. Water-control structures also altered upstream water levels in all canals. Water levels were lowered upstream from tide gates, but increased upstream from flashboard risers. Both types of water-control structures attenuated the release of runoff following rainfall events, but in slightly different ways. Tide gates appeared to reduce peak discharge rates associated with rainfall, and flashboard risers lengthened the duration of runoff release. Tide gates had no apparent effect on pH, dissolved oxygen, suspended-sediment, or total phosphorus concentrations downstream from the structures. Specific conductance measured from composite samples collected with automatic samples increased downstream of tide gates after installation. Median concentrations of nitrite plus nitrate nitrogen were near the minimum detection level throughout the study; however, the number of observations of concentrations exceeding 0.1 milligram per liter dropped significantly after tide gates were installed. Following tide-gate installation, instantaneous loadings of nitrite plus nitrate nitrogen were significantly reduced at one test site, but this reduction was not observed at the other test site. Loadings of other nutrient species and suspended sediment did not change at the tide-gate test sites after tide-gate installation. Specific conductance was lower in the Beaufort County canals than in the Hyde County canals. Although there was a slight increase in median values at the flashboard-riser sites, the mean and maximum values declined substantially downstream from the risers following installation. This decline of specific conductance in the canals occurred despite a large increase of specific conductance in the tidal creek. Flashboard risers had no significant effect on concentrations of dissolved oxygen, suspended sediment, total ammonia plus organic nitrogen, or phosphorus. Maximum concentrations of ammonia nitrogen were smaller at both test sites after riser installation. In addition, concentrations of nitrite plus nitrate nitrogen exceeding 1.0 milligram per liter rarely occurred at the flashboard-riser test sites following installation of the risers. Median loadings of nitrite plus nitrate nitrogen and total nitrogen decreased at one riser test site following flashboard-riser installation. Tide gates and flashboard risers were associated with reductions in concentrations and export of nitrite plus nitrate nitrogen; however, these changes should be interpreted cautiously because reductions were not observed consistently at every site. The hydrology and baseline water-quality characteristics of the two study areas differ, making comparisons of the effectiveness of the two types of water-control structures difficult to interpret. The effects of water-control structures on the hydrology of the drainage canals are more meaningful than the changes in water quality. Tide gates and flashboard risers altered the hydrologic characteristics of the drainage canals and created an environment favorable for nutrient loss or transformation. Both structures retained agricultural drainage upstream, which increased potential storage for infiltration and reduced the potential for surface runoff, sediment, and nutrient transport, and higher peak outflow rates.

  6. Study of physico-chemical characteristics of water bodies around Jaipur.

    PubMed

    Srivastava, Neera; Agrawal, Meena; Tyagi, Anupama

    2003-04-01

    The present study has been undertaken to evaluate physico-chemical parameters (pH, temperature, dissolved oxygen, free carbon dioxide, alkalinity and hardness) and zinc concentration in water bodies in and around Jaipur. Water samples from Jalmachal Lake, Nevta Lake, Amer Lake and Ramgarh Lake were analysed. Results reveal that the water of Jalmahal Lake is most polluted due to high pH, hardness, alkalinity, free carbon dioxide, zinc content, and a low level of dissolved oxygen. Contrarily Ramgarh Lake is least polluted, as it has high dissolved oxygen and low pH, alkalinity, free carbon dioxide, hardness and zinc content. PMID:12974460

  7. Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters

    NASA Technical Reports Server (NTRS)

    Witte, W. G.; Whitlock, C. H.; Usry, J. W.; Morris, W. D.; Gurganus, E. A.

    1981-01-01

    Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude.

  8. Determination of the Burning Characteristics of a Slick of Oil on Water 

    E-print Network

    Torero, Jose L; Olenick, Stephen M; Garo, Jean P; Vantelon, Jean P

    2003-01-01

    The burning rate of a slick of oil on a water bed is characterized by three distinct processes, ignition, flame spread and burning rate. Although all three processes are important, ignition and burning rate are critical. ...

  9. Evaluation of the Arya-Paris model for estimating water retention characteristics of lignitic mine soils

    SciTech Connect

    Buczko, U.; Gerke, H.H. [Brandenburg University of Technology, Cottbus (Germany)

    2005-07-01

    Mine soil materials may be viewed as man-made systems that consist of spatially disordered soil and sediment components, which are in an initial stage of soil development. A question is whether methods and approaches developed for natural soils, may also be used for such artificially created soil materials. The applicability of the Arya and Paris pedotransfer function to obtain hydraulic properties from the particle size distribution and bulk density was tested for lignitic mine soil material of the Lusatian Lignite Mining District in eastern Germany. The scaling factor a in this model was evaluated by (I) fitting of the water retention curves estimated with the Arya-Paris model (APM) to measured water retention data and (ii) interpretation of a as a fractal dimension of the pore channels and derivation of this fractal dimension from the fractal dimension of the particle size distribution. The two tested fractal approaches resulted in relatively inaccurate predictions of the water content. The use of a single fitted a value for each depth yielded a values between 1.05 and 1.47. Because of the inability of the APM to account for residual water contents in this sandy soil material, a correction was applied. The cumulative mass fraction fractal method did not improve the estimation in comparison with the retention curves calculated with a constant a value of 1.38. The closest fits with the data were obtained by using a variable a value that depended on the particle size. The accuracy of the predictions of the APM in the higher suction range could be improved (lower mean deviations and root mean square deviations of water content) by using a linear water content-dependent correction factor. Better estimates of water retention in the relatively dry range may be significant for simulation of water budgets of mine spoil sites in the Lusatian Mining District.

  10. CO 2-heat pump water heater: characteristics, system design and experimental results

    Microsoft Academic Search

    Petter Nekså; Håvard Rekstad; G. Reza Zakeri; Per Arne Schiefloe

    1998-01-01

    CO2 is one of the few non-toxic and non-flammable working fluids that do not contribute to ozone depletion or global warming, if leaked to the atmosphere. Tap water heating is one promising application for a trans-critical CO2 process. The temperature glide at heat rejection contributes to a very good temperature adaptation when heating tap water, which inherits a large temperature

  11. Neutron transport with the method of characteristics for 3-D full core boiling water reactor applications

    Microsoft Academic Search

    Justin W. Thomas

    2006-01-01

    The Numerical Nuclear Reactor (NNR) is a code suite that is being developed to provide high-fidelity multi-physics capability for the analysis of light water nuclear reactors. The focus of the work here is to extend the capability of the NNR by incorporation of the neutronics module, DeCART, for Boiling Water Reactor (BWR) applications. The DeCART code has been coupled to

  12. Biochar as a Substitute for Peat in Greenhouse Growing Media: Soil Water Characteristics and Carbon Leaching Dynamics

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Hilbert, I.; Jollymore, A. J.

    2012-12-01

    Biochar (charcoal derived from waste biomass via pyrolysis) has the potential to be used as part of regional scale carbon sequestration strategies. By providing a stable form of carbon that is resistant to decay in soils, biochar can be utilized in a wide range of applications to improve the sustainability of land use management practices. Due to its high water holding capacity, surface area and charge density, it could provide a substitute for peat that is widely used in horticultural activities. Globally, peat production in 2010 amounted to 23.4 Mt, with more than a third of this used for horticulture. In Canada, essentially all peat produced is used for horticulture, with each ton of peat extracted also contributing about 0.7 t CO2e in combined greenhouse gas emissions related to production, transportation and use of peat. We evaluated biochar produced on farm from red alder as a peat substitute in terms of soil water characteristics and carbon leaching in greenhouse growing media (e.g. potting mix). Biochar mixing ratios of 10% (v/v) and greater provided water holding capacity equivalent to peat-based potting mixes. We also present results from a laboratory wetting experiment in which we characterized leachate for dissolved organic carbon (DOC) concentration and DOC characteristics using spectral methods (uV-Vis and fluorescence spectroscopy).

  13. [Spatio-temporal characteristics and source identification of water pollutants in Wenruitang River watershed].

    PubMed

    Ma, Xiao-xue; Wang, La-chun; Liao, Ling-ling

    2015-01-01

    Identifying the temp-spatial distribution and sources of water pollutants is of great significance for efficient water quality management pollution control in Wenruitang River watershed, China. A total of twelve water quality parameters, including temperature, pH, dissolved oxygen (DO), total nitrogen (TN), ammonia nitrogen (NH4+ -N), electrical conductivity (EC), turbidity (Turb), nitrite-N (NO2-), nitrate-N(NO3-), phosphate-P(PO4(3-), total organic carbon (TOC) and silicate (SiO3(2-)), were analyzed from September, 2008 to October, 2009. Geographic information system(GIS) and principal component analysis(PCA) were used to determine the spatial distribution and to apportion the sources of pollutants. The results demonstrated that TN, NH4+ -N, PO4(3-) were the main pollutants during flow period, wet period, dry period, respectively, which was mainly caused by urban point sources and agricultural and rural non-point sources. In spatial terms, the order of pollution was tertiary river > secondary river > primary river, while the water quality was worse in city zones than in the suburb and wetland zone regardless of the river classification. In temporal terms, the order of pollution was dry period > wet period > flow period. Population density, land use type and water transfer affected the water quality in Wenruitang River. PMID:25898648

  14. Water and sediment characteristics associated with avian botulism outbreaks in wetlands

    USGS Publications Warehouse

    Rocke, Tonie E.; Samuel, Michael D.

    1999-01-01

    Avian botulism kills thousands of waterbirds annually throughout North America, but management efforts to reduce its effects have been hindered because environmental conditions that promote outbreaks are poorly understood. We measured sediment and water variables in 32 pairs of wetlands with and without a current outbreak of avian botulism. Wetlands with botulism outbreaks had greater percent organic matter (POM) in the sediment (P = 0.088) and lower redox potential in the water (P = 0.096) than paired control wetlands. We also found that pH, redox potential, temperature, and salinity measured just above the sediment-water interface were associated (P ? 0.05) with the risk of botulism outbreaks in wetlands, but relations were complex, involving nonlinear and multivariate associations. Regression models indicated that the risk of botulism outbreaks increased when water pH was between 7.5 and 9.0, redox potential was negative, and water temperature was >20°C. Risk declined when redox potential increased (>100), water temperature decreased (10-15°C), pH was 9.0, or salinity was low (<2.0 ppt). Our predictive models could allow managers to assess potential effects of wetland management practices on the risk of botulism outbreaks and to develop and evaluate alternative management strategies to reduce losses from avian botulism.

  15. Characteristics of interfacial water affected by proteins adsorbed on activated carbon.

    PubMed

    Alexeeva, T A; Lebovka, N I; Gun'ko, V M; Strashko, V V; Mikhalovsky, S V

    2004-10-15

    The influence of proteins (bovine serum albumin, BSA, and mouse gamma-globulin, IgG) physically adsorbed or covalently attached via coupling with N-cyclohexyl-N'-(2-morpholinoethyl) carbodiimide methyl-p-toluenesulfonate, CMC, to the surface of activated carbon SCN (spherical carbon with nitrogen) on the mobility of interfacial water molecules was studied by means of 1H NMR spectroscopy with freezing-out of bulk water at 180 < T < 273 K. Relaxation processes in the interfacial non-freezing water were investigated measuring transverse time t2 of proton relaxation dependence on the presence of proteins and CMC. The distribution function of activation free energy of relaxation (with a maximum at 20-22 kJ/mol) was calculated for the protein-water-carbon systems using a regularization procedure and the relationships between t2 and the amounts of the interfacial water unfrozen at T < 250 K assuming the Arrhenius-type dependence for t2(-1) on temperature. The state of unfrozen water in pores of SCN shows that the low temperature relaxation processes occur in narrow pores with half-width X < 1.5 nm. PMID:15450452

  16. Hydrogeologic and water-quality characteristics of the Prairie du Chien-Jordan aquifer, Southeast Minnesota

    USGS Publications Warehouse

    Ruhl, J.F.; Wolf, R.J.; Adolphson, D.G.

    1983-01-01

    The Prairie du Chien-Jordan aquifer is part of a sequence of sedimentary bedrock units in southeast Minnesota. The Jordan Sandstone is a white to yellow, fine- to coarse-grained sandstone. The Prairie du Chien Group comprises two dolomitic formations, which are vuggy and fractured and interbedded with thin layers of shale. The aquifer was deposited from Paleozoic seas that occupied the Hollandale embayment. The surface of the aquifer dips toward the interior of the embayment where it is as deep as 750 feet below land surface and as thick as 500 feet. Permeability is secondary in the Prairie du Chien Group because of solution cavities and fractures and is intergranular in the Jordan Sandstone. Water in the aquifer is confined and generally flows to the north and east into the Minnesota and Mississippi Rivers. A ground-water divide separates part of the flow southward into Iowa. This aquifer supplies more water than any other in the State. Quality of water is generally good throughout the aquifer. Calcium magnesium bicarbonate type water is most common. The potential for contamination from surface sources is low except near the Mississippi River valley, where the overlying drift is thin. The most serious water-quality problem is contamination by chemical wastes in St. Louis Park. (USGS)

  17. Availability and chemical characteristics of ground water in central La Plata County, Colorado

    USGS Publications Warehouse

    Brogden, R.E.; Giles, T.F.

    1976-01-01

    The central part of La Plata County, Colo., has undergone rapid population growth in recent years. This growth has resulted in an increased demand for information for additional domestic, industrial, and municipal water supplies. A knowledge of the occurrence of ground water will permit a more efficient allocation of the resource. Aquifers in central La Plata County include: alluvium, Animas Formation of Quaternary and Tertiary age, Fruitland Formation, Pictured Cliffs Sandstone, three formations of the Mesa Verde Group, the Mancos Shale, Dakota Sandstone, Morrison Formation of Cretaceous and Jurassic age, and undifferentiated formations. Well yields generally are low, usually less than 25 gallons per minute. However, higher yields, 25 to 50 gallons per minute may be found locally in aquifers in the alluvium and the Animas Formation. The quality of water from the aquifers is dependent on rock type. Most of the water is a calcium bicarbonate type. However, aquifers that are predominantly fine-grained or contain interbeds of shale may contain sodium bicarbonate type water. The dissolution of minerals in the coal beds, which are present in the Mesa Verde Group and the Dakota Sandstone, can contribute high concentrations of iron, sulfate, and chloride to ground water. (Woodard-USGS)

  18. ORIGINAL ARTICLE Sequentiality of Daily Life Physiology: An Automatized

    E-print Network

    Fontecave-Jallon, Julie

    ORIGINAL ARTICLE Sequentiality of Daily Life Physiology: An Automatized Segmentation Approach J on the hypotheses that (1) a physiological organization exists inside each activity of daily life and (2) the pattern of evolution of physiological variables is characteristic of each activity, pattern changes should

  19. Factors controlling physico-chemical characteristics in the coastal waters off Mangalore-A multivariate approach

    SciTech Connect

    Shirodkar, P.V. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India)], E-mail: shirod@nio.org; Mesquita, A.; Pradhan, U.K.; Verlekar, X.N.; Babu, M.T.; Vethamony, P. [National Institute of Oceanography, Dona Paula, Goa 403 004 (India)

    2009-04-15

    Water quality parameters (temperature, pH, salinity, DO, BOD, suspended solids, nutrients, PHc, phenols, trace metals-Pb, Cd and Hg, chlorophyll-a (chl-a) and phaeopigments) and the sediment quality parameters (total phosphorous, total nitrogen, organic carbon and trace metals) were analysed from samples collected at 15 stations along 3 transects off Karnataka coast (Mangalore harbour in the south to Suratkal in the north), west coast of India during 2007. The analyses showed high ammonia off Suratkal, high nitrite (NO{sub 2}-N) and nitrate (NO{sub 3}-N) in the nearshore waters off Kulai and high nitrite (NO{sub 2}-N) and ammonia (NH{sub 3}-N) in the harbour area. Similarly, high petroleum hydrocarbon (PHc) values were observed near the harbour, while phenols remained high in the nearshore waters of Kulai and Suratkal. Significantly, high concentrations of cadmium and mercury with respect to the earlier studies were observed off Kulai and harbour regions, respectively. R-mode varimax factor analyses were applied separately to surface and bottom water data sets due to existing stratification in the water column caused by riverine inflow and to sediment data. This helped to understand the interrelationships between the variables and to identify probable source components for explaining the environmental status of the area. Six factors (each for surface and bottom waters) were found responsible for variance (86.9% in surface and 82.4% in bottom) in the coastal waters between Mangalore and Suratkal. In sediments, 4 factors explained 86.8% of the observed total variance. The variances indicated addition of nutrients and suspended solids to the coastal waters due to weathering and riverine transport and are categorized as natural sources. The observed contamination of coastal waters indicated anthropogenic inputs of Cd and phenol from industrial effluent sources at Kulai and Suratkal, ammonia from wastewater discharges off Kulai and harbour, PHc and Hg from boat traffic and harbour activities of New Mangalore harbour. However, the strong seasonal currents and the seasonal winds keep the coastal waters well mixed and aerated, which help to disperse the contaminants, without significantly affecting chlorophyll-a concentrations. The interrelationship between the stations as shown by cluster analyses and depicted in dendograms, categorize the contamination levels sector-wise.

  20. Thermal desorption characteristics of CO, O2 and CO2 on non-porous water, crystalline water and silicate surfaces at sub-monolayer and multilayer coverages

    E-print Network

    Noble, J A; Dulieu, F; Fraser, H J

    2011-01-01

    The desorption characteristics of molecules on interstellar dust grains are important for modelling the behaviour of molecules in icy mantles and, critically, in describing the solid-gas interface. In this study, a series of laboratory experiments exploring the desorption of three small molecules from three astrophysically relevant surfaces are presented. The desorption of CO, O2 and CO2 at both sub-monolayer and multilayer coverages was investigated from non-porous water, crystalline water and silicate surfaces. Experimental data was modelled using the Polanyi-Wigner equation to produce a mathematical description of the desorption of each molecular species from each type of surface, uniquely describing both the monolayer and multilayer desorption in a single combined model. The implications of desorption behaviour over astrophysically relevant timescales are discussed.

  1. Associations between soil texture, soil water characteristics and earthworm populations in grassland

    Microsoft Academic Search

    Martin Holmstrup; Mathieu Lamandé; Søren B. Torp; Mogens H. Greve; Rodrigo Labouriau; Goswin Heckrath

    2011-01-01

    The aim of the present study was to investigate the relationships between soil physical characteristics and earthworms in a regional-scale field study in Denmark. The earthworm populations along within-field gradients in soil texture were quantified at five field sites, representing dominant soil types of Denmark. Eleven earthworm species were found, but populations were mainly dominated by Aporrectodea tuberculata and A.

  2. Characteristics of oceanic impact-induced large water waves---Re-evaluation of the tsunami hazard

    Microsoft Academic Search

    Kai Wünnemann; Robert Weiss; Kay Hofmann

    2007-01-01

    The potential hazard of a meteorite impact in the ocean is controversial with respect to the destructive power of generated large ocean waves (tsunamis). We used numerical modeling of hypervelocity impact to investigate the generation mechanism and the characteristics of the resulting waves up to a distance of 100-150 projectile radii. The wave signal is primarily controlled by the ratio

  3. Characteristics of Marine Aggregates in Shallow-water Ecosystems: Implications for Disease Ecology

    E-print Network

    Allam, Bassem

    , USA 3 School of Aquatic & Fishery Sciences, University of Washington, Seattle, WA USA 4 Marine for their potential role in the ecology of aquatic pathogens using underwater video surveys coupled with direct, and Massachusetts, were surveyed over 8 months to explore differences in the characteristics of aggregates found

  4. Characteristics of produced water discharged to the Gulf of Mexico hypoxiczone.

    SciTech Connect

    Veil, J. A.; Kimmell, T. A.; Rechner, A. C.

    2005-08-24

    Each summer, an area of low dissolved oxygen (the hypoxic zone) forms in the shallow nearshore Gulf of Mexico waters from the Mississippi River Delta westward to near the Texas/Louisiana border. Most scientists believe that the leading contributor to the hypoxic zone is input of nutrients (primarily nitrogen and phosphorus compounds) from the Mississippi and Atchafalaya Rivers. The nutrients stimulate growth of phytoplankton. As the phytoplankton subsequently die, they fall to the bottom waters where they are decomposed by microorganisms. The decomposition process consumes oxygen in the bottom waters to create hypoxic conditions. Sources other than the two rivers mentioned above may also contribute significant quantities of oxygen-demanding pollutants. One very visible potential source is the hundreds of offshore oil and gas platforms located within or near the hypoxic zone. Many of these platforms discharge varying volumes of produced water. However, only limited data characterizing oxygen demand and nutrient concentration and loading from offshore produced water discharges have been collected. No comprehensive and coordinated oxygen demand data exist for produced water discharges in the Gulf of Mexico. This report describes the results of a program to sample 50 offshore oil and gas platforms located within the Gulf of Mexico hypoxic zone. The program was conducted in response to a requirement in the U.S. Environmental Protection Agency (EPA) general National Pollutant Discharge Elimination System (NPDES) permit for offshore oil and gas discharges. EPA requested information on the amount of oxygen-demanding substances contained in the produced water discharges. This information is needed as inputs to several water quality models that EPA intends to run to estimate the relative contributions of the produced water discharges to the occurrence of the hypoxic zone. Sixteen platforms were sampled 3 times each at approximately one-month intervals to give an estimate of temporal variability. An additional 34 platforms were sampled one time. The 50 sampled platforms were scattered throughout the hypoxic zone to give an estimate of spatial variability. Each platform was sampled for biochemical oxygen demand (BOD), total organic carbon (TOC), nitrogen (ammonia, nitrate, nitrite, and total Kjeldahl nitrogen [TKN]), and phosphorus (total phosphorus and orthophosphate). In addition to these parameters, each sample was monitored for pH, conductivity, salinity, and temperature. The sampling provided average platform concentrations for each parameter. Table ES-1 shows the mean, median, maximum, and minimum for the sampled parameters. For some of the parameters, the mean is considerably larger than the median, suggesting that one or a few data points are much higher than the rest of the points (outliers). Chapter 4 contains an extensive discussion of outliers and shows how the sample results change if outliers are deleted from consideration. A primary goal of this study is to estimate the mass loading (lb/day) of each of the oxygen-demanding pollutants from the 50 platforms sampled in the study. Loading is calculated by multiplying concentrations by the discharge volume and then by a conversion factor to allow units to match. The loadings calculated in this study of 50 platforms represent a produced water discharge volume of about 176,000 bbl/day. The total amount of produced water generated in the hypoxic zone during the year 2003 was estimated as 508,000 bbl/day. This volume is based on reports by operators to the Minerals Management Service each year. It reflects the volume of produced water that is generated from each lease, not the volume that is discharged from each platform. The mass loadings from offshore oil and gas discharges to the entire hypoxic zone were estimated by multiplying the 50-platform loadings by the ratio of total water generated to 50-platform discharge volume. The loadings estimated for the 50 platforms and for the entire hypoxic zone are shown in Table ES-2. These estimates and the sampling data from 50 platfo

  5. Differential summer water use by Pinus edulis and Juniperus osteosperma reflects contrasting hydraulic characteristics.

    PubMed

    West, A G; Hultine, K R; Jackson, T L; Ehleringer, J R

    2007-12-01

    Previous studies of pinyon-juniper woodlands show that Pinus edulis Engelm. makes better use of soil water from summer precipitation pulses than does co-occurring Juniperus osteosperma (Torr.) Little. To investigate the basis of this difference, we examined seasonal variation in cavitation and hydraulic conductance. Pinus edulis remained isohydric over the growing season. Minimum water potentials never fell below -2.3 MPa, and the extent of xylem cavitation remained near constant during the dry season. In contrast, J. osteosperma was anisohydric, reaching water potentials as low as -6.9 MPa, and experiencing progressively greater xylem cavitation as the dry season progressed despite having more cavitation-resistant xylem than P. edulis. We conducted an irrigation experiment to observe the responses of the study species to a summer pulse of water. Although sap flow increased in both species in response to the 25-mm irrigation pulse, only J. osteosperma responded to the 10-mm pulse. This was inconsistent with the response of P. edulis to light rain events and may have been due to a difference in the distribution of irrigation water and rain water between the under- and between-canopy areas. Whole-plant conductance increased following the 25-mm irrigation in P. edulis but remained constant in J. osteosperma. We hypothesized that this difference was caused, in part, by differential refilling of embolized xylem. Area specific hydraulic conductivity was 66% higher in roots of irrigated P. edulis trees relative to roots of control trees 3 days after the 25-mm irrigation (t = 2.14, P = 0.02, df = 16). There was no change in hydraulic conductivity of the roots of J. osteosperma or in the stems of either species. Our results indicate that the response to an irrigation pulse in P. edulis depended on cavitation avoidance in stems and the reversal of cavitation in roots, resulting in increased whole-plant conductance and water uptake. In contrast, J. osteosperma failed to exploit light summer rain events but was able to extract deep soil water at low water potentials. PMID:17938102

  6. Seismic characteristics of two deep-water drilling hazards: Shallow-water flow sands and gas hydrate

    NASA Astrophysics Data System (ADS)

    Lu, Shaoming

    A 3D simultaneous Amplitude Variation with Angle (AVA) Inversion is applied to three common-angle aperture prestack time migrated 3D data volumes from the Garden Banks area of the Gulf of Mexico, to obtain a seismic compressional to shear velocity (Vp/Vs) ratio volume. With constraints and calibrations from two wells, high Vp/Vs anomalies (>9) inverted from conventional seismic data are used to identify potential shallow water flow (SWF) sands away from the wells. The results show that V p/Vs values are more diagnostic than seismic amplitudes alone for SWF sand detection. Elastic seismic amplitude variation with angle data provide unreliable indicators where SWF sands are thin (where interference occurs between reflections from the layer tops and bottoms) or if viscoelasticity is significant. A new approach based on empirical relations provides cost-effective estimates of the saturation, concentration and distribution of gas hydrate and free-gas away from the control wells. The water-filled porosity is calibrated to acoustic impedance twice; one calibration is used where gas hydrate is present, and the other, where free-gas is present. The water-filled porosity is then used to estimate gas hydrate or free-gas saturations. The method is first developed and evaluated using well logs from Ocean Drilling Program (ODP) Leg 164 from the Blake Ridge area off the east coast of North America, and then applied to a single channel seismic line from that area. The results match well with other independent estimations. An elastic impedance inversion is applied to four time-migrated common-angle aperture (CAA) data sets. Two new algorithms are developed and evaluated using well-log data from ODP Leg 164 to estimate P-impedance and S-impedance from the elastic impedance. The Vs/Vp ratio, Poisson's ratio, and Lame parameter terms lambdarho and lambda/mu are estimated from the P-impedance and S-impedance. The results show that the hydrated sediments have high elastic impedance, high P-impedance, high S-impedance, high lambdarho, slightly higher Vs/Vp ratio, slightly lower Poisson's ratio and slightly lower lambda/mu values compared to those of the surrounding unhydrated sediments. The sediments containing free-gas have low elastic impedance, low P-impedance, non-anomalous background S-impedance, high Vs/Vp ratio, low Poisson's ratio, low lambdarho, and low lambda/mu values.

  7. Soil water characteristics of two soil catenas in Illinois: Implications for irrigation

    SciTech Connect

    Schaetzl, R.J. (Michigan State Univ., East Lansing (United States)); Kirsch, S.W. (Memphis State Univ., TN (United States)); Hendrie, L.K.

    1989-10-01

    Soil water was monitored by neutron scattering in six soils, three each within two drainage catenas in east-central Illinois, over a 15-month time span. The prairie soils have formed in: (1) 76-152 cm of silt loam, eolian sediments (loess) over glacial till (Catlin-Flanagan-Drummer catena), and (2) loess greater than 152 cm in thickness (Tama-Ipava-Sable catena). The authors characterized the water content of these soils over the total time span and for wet and dry climatic subsets, as an aid to potential irrigation decisions. Soils of the thin loess, C-F-D catena dried out to lower water contents and had greater soil water variability than did the thick loess soils. Under wet conditions, soil water contents in the two catenas were quite similar. Alleviation of surface and subsurface drying via irrigation would thus be more advantageous to yields on the C-F-D soils than on the T-I-S soils.

  8. Characteristics of the ground-water seepage into Great South Bay. Special Report 35

    SciTech Connect

    Bokuniewicz, H.J.; Zeitlin, M.J.

    1980-03-01

    The water quality and salinity in Great South Bay represent a balance between the amount of seawater that enters the bay through its inlets and the amount of freshwater that is supplied from Long Island. Streamflow accounts for most of the freshwater supplied to the bay. The second largest contribution is the submarine outflow of ground water across the bay floor. Direct measurements of this source are reported here. Preliminary work showed that much of the seepage occurred within 100 meters of the shore. Submarine outflow rates were as high as 150 liters/day/square meter. The outflow near the shore was typically 50 liters/day/square meter and decreased to about 30 liters/day/square meter at a distance of 100 meters offshore. Variations in the outflow rate due to tidal changes in the water level could not be detected. The flow rate did appear to be sensitive to coastal flooding and rainfall, however. In order to calculate the total submarine outflow, the data were described as decreasing exponentially with distance from shore. The typical value of the submarine outflow was calculated to be 4.1 x 10/sup 8/ liters/day. This calculation excluded measurements made near Fire Island, but they suggest that significant amounts of ground water may enter the bay far from shore due to sustained, upward leakage from deep aquifers. As a result, the calculated value is an underestimate. The outflow rates are relatively large and should significantly affect the pore water chemistry.

  9. Coal-water slurry spray characteristics of a positive displacement fuel injection system

    SciTech Connect

    Seshadri, A.K.; Caton, J.A.; Kihm, K.D. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

    1992-12-31

    Experiments have been completed to characterized coal-water slurry sprays from a modified positive displacement fuel injection system of a diesel engine. The injection system includes an injection jerk pump driven by an electric motor, a specially designed diaphragm to separate the abrasive coal from the pump, and a single-hole fuel nozzle. The sprays were injected into a pressurized chamber equipped with windows. High speed movies and instantaneous fuel line pressures were obtained. For injection pressures of order 30 MPa or higher, the sprays were similar for coal-water slurry, diesel fuel and water. The time until the center core of the spray broke-up (break-up time) was determined from both the movies and from a model using the fuel line pressures. Results from these two independent procedures were in good agreement. For the base conditions, the break-up time was 0.58 and 0.50 ms for coal-water slurry and diesel fuel, respectively. The break-up times increased with increasing nozzle orifice size and with decreasing chamber density. The break-up time was not a function of coal loading for coal loadings up to 53%. Cone angles of the sprays were dependent on the operating conditions and fluid, as well as on the time and location of the measurement. For one set of cases studied, the time-averaged cone angle was 15.9{degree} and 16.3{degree} for coal-water slurry and diesel fuel, respectively.

  10. Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

    NASA Technical Reports Server (NTRS)

    Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

    2000-01-01

    This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

  11. Flow characteristics and injectivity behavior of water-soluble polymers: Final report. [144 references

    SciTech Connect

    Martin, F.D.

    1987-04-01

    The objective of this project was to determine the key properties of water-soluble polymers that affect injectivity of polymer solutions used in enhanced recovery processes. The project consisted of performing a thorough literature survey on this subject, followed by laboratory tests to assess various properties of polymer solutions. In the literature survey, laboratory and field projects were reviewed. Information from the literature survey on field projects and from experiments performed as part of this study points out that water quality is very important in the injectivity of polymer solutions. Specifically, if iron is introduced as a corrosion byproduct, the polymers can be crosslinked which can lead to severe plugging when the polymer solution is injected. For some polymers, procedures used for mixing solutions can be important. Higher solution viscosities may be obtained if emulsion polymers are inverted in a very fresh water prior to mixing with a brine water. Filterability and injectivity of some emulsion polymers are better when the polymers are dissolved in a fresher water. As expected, injectivity of xanthan gum polymers was better than for polyacrylamide polymers. For polyacrylamides, adsorption was higher on dolomite than on sandstone, but the adsorption on either media was not affected greatly by anionic charge of the polymers. Injectivity of polymer solutions may be improved by pretreatment with certain solvents or chemicals. After a loss of injectivity caused by plugging from a polymer solution, selected chemicals can provide improvement in injectivity. 155 refs., 30 figs., 27 tabs.

  12. Modulation of morpho-functional characteristics of astrocytes using chemically-functionalized water-soluble single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Gottipati, Manoj K.

    In this thesis, I report the use of chemically functionalized water-soluble single-walled carbon nanotubes (ws-SWCNTs) for the modulation of morpho-functional characteristics of astrocytes. When added to the culturing medium, ws-SWCNTs were able to make astrocytes larger and stellate/mature, changes associated with the increase in glial fibrillary acidic protein immunoreactivity. Thus, ws-SWCNTs could have more beneficial effects at the injury site than previously thought; by affecting astrocytes, they could provide for a more comprehensive re-establishment of the brain computational power. Keywords: Carbon nanotubes, graft copolymers, astrocytes, glial fibrillary acidic protein.

  13. Evaluation of hydraulic characteristics of a deep artesian aquifer from natural water-level fluctuations, Miami, Florida

    USGS Publications Warehouse

    Meyer, Frederick W.

    1974-01-01

    Knowledge of tho hydraulic characteristics of aquifer systems is fundamental to defining the vertical and horizontal controls on fluid movement, information which is needed for assessing the environmental impact of subsurface waste storage. To meet this objective, natural water-level fluctuations in the 2,947-foot deep Peninsula Utilities disposal well near Miami, Florida were analyzed to obtain estimates of the hydraulic diffusivity, hydraulic conductivity, specific storage, transmissivity, and the storage coefficient of the Boulder Zone. The fluctuations are caused chiefly by oceanic and earth tides, and by changes in atmospheric pressure. The oceanic tidal fluctuations probably result from loading due to tides in Biscayne Bay.

  14. Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes

    NASA Astrophysics Data System (ADS)

    Devasthale, A.; Sedlar, J.; Tjernström, M.

    2011-05-01

    An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002-2010) and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA). We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time. We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical representation of water-vapour inversions in models would mean that the large-scale coupling of moisture transport, precipitation, temperature and water vapour vertical structure and radiation are also essentially captured well in such models.

  15. Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes

    NASA Astrophysics Data System (ADS)

    Devasthale, A.; Sedlar, J.; Tjernström, M.

    2011-09-01

    An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002-2010) and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA). We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time. We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical representation of water-vapour inversions in models would mean that the large-scale coupling of moisture transport, precipitation, temperature and water-vapour vertical structure and radiation are essentially captured well in such models.

  16. [Characteristics of bottled waters available for purchase in the Silesia region].

    PubMed

    Krzych, ?ukasz J; B?o?ska-Fajfrowska, Barbara; Kula, Anna; Misik, Dominika

    2010-01-01

    The aim of the study was to characterize bottled waters available for purchase in the Silesia region in relation to total mineral contents and main ion concentrations. In descriptive epidemiological design, we investigated 70 types of available for purchase bottled waters (mineral, spring and table ones), sold in glass or PET bottles. On the basis of data revealed by producers, we analyzed total mineral contents and concentrations of main cations (sodium, magnesium, calcium and potassium) and anions (hydrocarbons, sulfate, chloride and fluoride). The study group comprised of 35 mineral waters and 35 spring waters. There were no table waters available for purchase. Total mineral content in mineral waters was 1310.0 +/- 814.8 mg/dm3, concentration of cations was 295.4 +/- 181.2 mg/dm3 and of anions: 968.1 +/- 638.5 mg/dm3. The concentrations of investigated cations were adequately: Ca 178.7 +/- 107.3 mg/dm3, Mg 54.3 +/- 52.7 mg/dm3, Na 53.5 +/- 67.4 mg/dm3 and K 8.9 +/- 9.4 mg/dm3. The contents of anions were: HCO3 930.5 +/- 647.2 mg/dm3, SO4 25.9 +/- 21.6 mg/dm3, Cl 11.5 +/- 11.2 mg/dm3 and F 0.2 +/- 0.27 mg/dm3. In relation to spring waters, total mineral content was 365.9 +/- 150.8 mg/dm3 and concentrations of cations and anions were adequately: 87.9 +/- 37.6 mg/dm3 and 255.1 +/- 111.9 mg/dm3. The concentrations of analyzed cations were adequately: Ca 55.4 +/- 19.7 mg/dm3, Mg 10.6 +/- 6.9 mg/dm3, Na 20.6 +/- 30.3 mg/dm3 and K 1.3 +/- 1.7 mg/dm3. For anions the concentrations were as follows: HCO3 223.2 +/- 105.8 mg/dm3, SO4 18.9 +/- 19.1 mg/dm3, Cl 12.9 +/- 16.5 mg/dm3 and F 0.11 +/- 0.12 mg/dm3. The quantity of available for purchase mineral waters is similar to spring waters. Total mineral content is on average 4-fold higher for mineral than spring waters. The variation of investigated ions concentrations is higher for mineral than spring waters. Both mineral and spring waters differ the most in relation to Na and K concentrations, and Cl and F contents. PMID:20803898

  17. Physiology & Development of Chronic Fear

    E-print Network

    Dennis, Nancy

    Physiology & Development of Chronic Fear (Behavioral Neuroendocrinology Lab) Sonia Cavigelli (PI A Individual B interest fear physiology physiology Individual A Temperament, Physiology, and Health health health Overarching Question: How do individual difference in behavior and physiology influence health

  18. Influence of framework silica-to-alumina ratio on the water adsorption and desorption characteristics of MHI-CaX\\/CaY zeolite

    Microsoft Academic Search

    Yasunori Iwai; Nobuki Oka; Toshihiko Yamanishi

    2009-01-01

    The influence of the framework SiO2\\/Al2O3 ratio from 2.0 to 10.0 of commercial faujasite-type CaX\\/CaY zeolite produced by Mitsubishi Heavy Industries Ltd. (MHI) on the water adsorption and desorption characteristics was investigated. Not only the change in electronegativity of the zeolite but the change in pore-size distribution of the zeolite affects the water adsorption and desorption characteristics of the zeolite.

  19. Characteristics of nutrients in the Jiulong River and its impact on Xiamen Water, China

    NASA Astrophysics Data System (ADS)

    Chen, Baohong; Ji, Weidong; Chen, Jinmin; Lin, Cai; Huang, Haining; Huo, Yunlong; Ji, Xianbiao

    2013-09-01

    Water samples were collected at 20 sites on 4 occasions in 2009 (twice in May, and once in both August and November) along the Jiulong River, South China to examine how nutrient inputs from the Jiulong River could affect the nutrient status of the Xiamen Water. Samples were analyzed for nitrite (NO2-N), nitrate (NO3-N), ammonium (NH4-N), phosphate (PO4-P), silicate (SiO3-Si), salinity, and temperature, to determine the nutrient and trophic status of the river. The results indicate that nutrients are derived mainly from river runoff. NO3-N was the main form of DIN in most parts of the river. In addition, NO3-N, DIN, and SiO3-Si behave conservatively. There is a surplus of DIN and SiO3-Si in the river, and PO4-P is a limitation on phytoplankton growth. The concentration of DIN is typically above 0.60 mg/dm3, and higher than 1.00 mg/dm3 in most parts of the river. The concentration of PO4-P is typically above 0.02 mg/dm3, while the concentration of SiO3-Si is higher than 1.00 mg/dm3. Between 2003 and 2008, samples were collected 3 times per year (May, August and November) at 27 sites in the Xiamen Water and analyzed for NO2-N, NO3-N, NH4-N, PO4-P, salinity, and temperature. We discovered that the Jiulong River was the key source of DIN into the Xiamen Water, but not PO4-P, indicating the reason of the N/P molar ratio imbalance in the Xiamen Water. In the future, the effects of high DIN concentrations on the phytoplankton communities and marine ecosystems of the Xiamen Water shall be studied.

  20. Synergetic effect of temperature and pressure on energetic and structural characteristics of {ZIF-8 + water} molecular spring

    NASA Astrophysics Data System (ADS)

    Grosu, Ya.; Renaudin, G.; Eroshenko, V.; Nedelec, J.-M.; Grolier, J.-P. E.

    2015-05-01

    Metal-organic frameworks (MOFs) and particularly their subclass - Zeolite Imidazolate Frameworks (ZIFs) - are used for a variety of applications including particularly energy storage. Highly porous MOFs mixed with non-wetting liquids can be used to form molecular springs (MS) for efficient mechanical and thermal energy storage/transformation. In this paper by means of high-pressure calorimetry the energetic characteristics of {ZIF-8 + water} MS were investigated in wide temperature and pressure ranges. Unexpectedly XRD measurements show that the concomitant effects of temperature and pressure on {ZIF-8 + water} MS leads to an irreversible change of the ZIF-8 structure, transforming its symmetry from cubic to orthorhombic. Whereas, previous studies have demonstrated the stability of ZIF-8 under either high pressure or high temperature.Metal-organic frameworks (MOFs) and particularly their subclass - Zeolite Imidazolate Frameworks (ZIFs) - are used for a variety of applications including particularly energy storage. Highly porous MOFs mixed with non-wetting liquids can be used to form molecular springs (MS) for efficient mechanical and thermal energy storage/transformation. In this paper by means of high-pressure calorimetry the energetic characteristics of {ZIF-8 + water} MS were investigated in wide temperature and pressure ranges. Unexpectedly XRD measurements show that the concomitant effects of temperature and pressure on {ZIF-8 + water} MS leads to an irreversible change of the ZIF-8 structure, transforming its symmetry from cubic to orthorhombic. Whereas, previous studies have demonstrated the stability of ZIF-8 under either high pressure or high temperature. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01340b

  1. Physiological dysfunction of the haemopoietic system in a fresh water teleost, Labeo rohita , following chronic chlordane exposure. Part II — Alterations in certain organic components and serum electrolytes

    Microsoft Academic Search

    S. K. Bansal; S. R. Verma; A. K. Gupta; R. C. Dalela

    1979-01-01

    Clinical chemical analysis used in mammaliam studies are highly developed amd reliable, but omly modest application of the principles and methods bave been extended te the realm of aquatic organisms. However, there is accumulating evidence that valid and useful analytical relations can be drawn between biochemical - physialsgical factors and pathology of an aquatic species. Physiological changes in the blod

  2. [Characteristics of delta18O in precipitation and water vapor sources in Lanzhou City and its surrounding area].

    PubMed

    Chen, Fen-Li; Zhang, Ming-Jun; Ma, Qian; Li, Xiao-Fei; Wang, Sheng-Jie; Li, Fei

    2013-10-01

    Based on the 243 daily precipitation samples and meteorological statistics at the four stations at Lanzhou city and its surrounding area (Yongdeng, Gaolan and Yuzhong) from April 2011 to March 2012, the characteristics of stable isotopes in precipitation, as well as the correlation between stable isotopes and meteorological records, were analyzed. The precipitation equation of Lanzhou city and its surrounding area were calculated through the regression analysis, and the water vapor source of the four sites was tracked by the HYSPLIT 4. 9 model, and water vapor transmission regime was established. Results showed that the precipitation equation of deltaD =7.48 delta18O + 8.13 indicated intense evaporation; delta18O value was low in winter but high in summer; The variations of observed d-excess was stable all over the year, but there was variation in different time periods; The spatial distribution showed that the weighted delta18O value decreased from the west to the east; The linear relationships between delta18O and temperature was positive correlation, but the linear relationships between delta18O and precipitation was negative correlation; The seasonal variations of delta18O indicated that westerly water vapor, local moisture and summer monsoon all had influence on this region in a large scale, but the westerly water vapor played a dominant role. However, the impact of monsoon moisture had a seasonal limitation, mainly during the period from June to early August. PMID:24364289

  3. Change in the bisphenol A content in a polycarbonate orthodontic bracket and its leaching characteristics in water.

    PubMed

    Watanabe, M; Hase, T; Imai, Y

    2001-12-01

    The change in the bisphenol A (BPA) content in a polycarbonate (PC) orthodontic bracket and its leaching characteristics were studied by immersing the bracket in water because BPA has been the matter of controversy in dentistry due to its estrogenic potential. PC brackets were placed in water at 37 degrees C and 60 degrees C and the BPA content in the bracket and the amount of BPA released into the water were analyzed at appropriate intervals by high performance liquid chromatography. The BPA content increased in the water with time and was 3.8-fold after 12 months at 37 degrees C and 12.4-fold after 14 weeks at 60 degrees C compared with the virgin value. The rate of BPA release also increased with time. The results suggested that BPA was released from the bracket time-dependently in the oral cavity. However, it was assessed that little or no estrogenic effect due to the released BPA is expected in the human body. PMID:11915629

  4. Evidence and characteristics of a diverse and metabolically active microbial community in deep subsurface clay borehole water.

    PubMed

    Wouters, Katinka; Moors, Hugo; Boven, Patrick; Leys, Natalie

    2013-12-01

    The Boom Clay in Belgium is investigated in the context of geological nuclear waste disposal, making use of the High Activity Disposal Experimental Site (HADES) underground research facility. This facility, located in the Boom Clay at a depth of 225 m below the surface, offers a unique access to a microbial community in an environment, of which all geological and geochemical characteristics are being thoroughly studied. This study presents the first elaborate description of a microbial community in water samples retrieved from a Boom Clay piezometer (borehole water). Using an integrated approach of microscopy, metagenomics, activity screening and cultivation, the presence and activity of this community are disclosed. Despite the presumed low-energy environment, microscopy and molecular analyses show a large bacterial diversity and richness, tending to correlate positively with the organic matter content of the environment. Among 10 borehole water samples, a core bacterial community comprising seven bacterial phyla is defined, including both aerobic and anaerobic genera with a range of metabolic preferences. In addition, a corresponding large fraction of this community is found cultivable and active. In conclusion, this study shows the possibility of a microbial community of relative complexity to persist in subsurface Boom Clay borehole water. PMID:23802615

  5. Nitrogen Removal Characteristics of a Newly Isolated Indigenous Aerobic Denitrifier from Oligotrophic Drinking Water Reservoir, Zoogloea sp. N299

    PubMed Central

    Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Bai, Shi-Yuan; He, Xiu-Xiu; Yang, Xiao

    2015-01-01

    Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This species exhibits a periplasmic nitrate reductase gene (napA). Its specific growth rate was 0.22 h?1. Obvious denitrification and perfect nitrogen removal performances occurred when cultured in nitrate and nitrite mediums, at rates of 75.53% ± 1.69% and 58.65% ± 0.61%, respectively. The ammonia removal rate reached 44.12% ± 1.61% in ammonia medium. Zoogloea sp. N299 was inoculated into sterilized and unsterilized reservoir source waters with a dissolved oxygen level of 5–9 mg/L, pH 8–9, and C/N 1.14:1. The total nitrogen removal rate reached 46.41% ± 3.17% (sterilized) and 44.88% ± 4.31% (unsterilized). The cell optical density suggested the strain could survive in oligotrophic drinking water reservoir water conditions and perform nitrogen removal. Sodium acetate was the most favorable carbon source for nitrogen removal by strain N299 (p < 0.05). High C/N was beneficial for nitrate reduction (p < 0.05). The nitrate removal efficiencies showed no significant differences among the tested inoculums dosage (p > 0.05). Furthermore, strain N299 could efficiently remove nitrate at neutral and slightly alkaline and low temperature conditions. These results, therefore, demonstrate that Zoogloea sp. N299 has high removal characteristics, and can be used as a nitrogen removal microbial inoculum with simultaneous aerobic nitrification and denitrification in a micro-polluted reservoir water ecosystem. PMID:25946341

  6. Nitrogen Removal Characteristics of a Newly Isolated Indigenous Aerobic Denitrifier from Oligotrophic Drinking Water Reservoir, Zoogloea sp. N299.

    PubMed

    Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Bai, Shi-Yuan; He, Xiu-Xiu; Yang, Xiao

    2015-01-01

    Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This species exhibits a periplasmic nitrate reductase gene (napA). Its specific growth rate was 0.22 h-1. Obvious denitrification and perfect nitrogen removal performances occurred when cultured in nitrate and nitrite mediums, at rates of 75.53% ± 1.69% and 58.65% ± 0.61%, respectively. The ammonia removal rate reached 44.12% ± 1.61% in ammonia medium. Zoogloea sp. N299 was inoculated into sterilized and unsterilized reservoir source waters with a dissolved oxygen level of 5-9 mg/L, pH 8-9, and C/N 1.14:1. The total nitrogen removal rate reached 46.41% ± 3.17% (sterilized) and 44.88% ± 4.31% (unsterilized). The cell optical density suggested the strain could survive in oligotrophic drinking water reservoir water conditions and perform nitrogen removal. Sodium acetate was the most favorable carbon source for nitrogen removal by strain N299 (p < 0.05). High C/N was beneficial for nitrate reduction (p < 0.05). The nitrate removal efficiencies showed no significant differences among the tested inoculums dosage (p > 0.05). Furthermore, strain N299 could efficiently remove nitrate at neutral and slightly alkaline and low temperature conditions. These results, therefore, demonstrate that Zoogloea sp. N299 has high removal characteristics, and can be used as a nitrogen removal microbial inoculum with simultaneous aerobic nitrification and denitrification in a micro-polluted reservoir water ecosystem. PMID:25946341

  7. Characteristics of MnO 2 catalytic ozonation of sulfosalicylic acid and propionic acid in water

    Microsoft Academic Search

    Shao-ping Tong; Wei-ping Liu; Wen-hua Leng; Qian-qing Zhang

    2003-01-01

    The characteristics of different types of MnO2 catalytic ozonation of sulfosalicylic acid (SSal) and propionic acid (PPA) have been investigated in this paper. The experimental results show the dependence of catalytic activity of MnO2 on organic compounds and the pH of solutions, but it is independent on the type of MnO2. For example, three types of MnO2 have not any

  8. Characteristics of effective industrial packings for evaporative cooling of circulating water in cooling towers

    Microsoft Academic Search

    A. M. Kagan; A. S. Pushnov; M. G. Berengarten; A. S. Ryabushenko; V. I. Shishov

    2009-01-01

    Results are presented for comparative tests of the aerothermal characteristics of basic types of regular packings on a test\\u000a bench developed by the Vedeneev All-Russia Research Institute of Hydraulic Engineering. These packings are widely used in\\u000a draft sections and similar cooling towers employed in the chemical and other branches of industry. It is demonstrated that\\u000a the drop-film type of packing

  9. Leaching and standing water characteristics of bottom ash and composted manure blends

    E-print Network

    Mathis, James Gregory

    2001-01-01

    ) runoff into surface water bodies. Alternative uses of bottom ash (BA) and composted manure (CM) such as a soil amendment for landscapes or potting media need to be explored. Before an alternative is adopted at a large scale, however, it must...

  10. Analysis of CDOM fluorescence spectrum characteristics in coastal water and its application

    NASA Astrophysics Data System (ADS)

    Xing, Xufeng; Lv, Xianqiang; Liu, Fang; Liu, Yuan; Zhan, Jie; Huang, Miaofen

    2014-05-01

    In accordance with the data which were experiment of mixing-ratio in water tank and collecting water samples in situ from natural seawater and urban sewage discharged into the sea along Dalian coast of the northern Yellow Sea in February and April 2012, with quinine sulfate and sodium humate as a reference, the calibration curve was established among CDOM (Chromophoric dissolved organic matter) concentration and fluorescence intensity and reference wave absorption coefficient. To calibration curve as the foundation, the CDOM samples concentration of various sources was determined after analyzing CDOM sample from Dalian coast of the northern Yellow Sea sewage into the sea and natural sea. Based on the comparative analysis on CDOM fluorescence fingerprint, the main component of water CDOM were determined. The results showed that in Dalian coastal waters of the northern Yellow Sea, the main component of CDOM in natural seawater is tryptophan and in urban sewage discharged into the sea are tryptophan, tyrosine, and humic acid. On the basis of comprehensive analysis of CDOM fluorescence and absorption spectral, the thinking of synergy inversion of CDOM absorption spectral slope S by connecting fluorescence and ocean color remote sensing is put forward.

  11. Some characteristics of air-water two-phase flow in small diameter vertical tubes

    Microsoft Academic Search

    K. Mishima; T. Hibiki

    1996-01-01

    Flow regime, void fraction, rise velocity of slug bubbles and frictional pressure loss were measured for air-water flows in capillary tubes with inner diameters in the range from 1 to 4 mm. Although some flow regimes peculiar to capillary tubes were observed in addition to commonly observed ones, overall trends of the boundaries between flow regimes were predicted well by

  12. Characteristics and SocioEconomic Evaluation of Two Indigenous Soil and Water Conservation Systems

    Microsoft Academic Search

    B. Kayombo; H. O. Dihenga; J. Ellis-Jones

    The most common indigenous soil and water conservation practices in Mbinga district are ngoro and matuta systems. The ngoro system enables the cultivation of land with steep slopes (10-60%) reducing soil erosion, maintaining fertility, and increasing soil moisture especially from April to July. Matuta with incorporation of plant residues have many of the advantages of increased fertility, organic matter content

  13. Leaching and standing water characteristics of bottom ash and composted manure blends 

    E-print Network

    Mathis, James Gregory

    2001-01-01

    volatile solids (TVS), total suspended solids (TSS), chemical oxygen demand (COD), TKN, NO?-N, ammonium (NH?-N), P, and K. Concentrations of nearly all chemicals were lower in standing water (top) compared to leachate (bottom) for acidic and alkaline...

  14. Atmospheric Environment 41 (2007) 62256235 Water uptake characteristics of individual atmospheric

    E-print Network

    2007-01-01

    and size changes for aerosol particles that could feed back into many other chemical and physical processes exhibited initial water uptake between 50% and 60% RH, although the first major morphological changes and that composition of the different phases within the coating affects deliquescence and hygroscopic growth below 76

  15. The Use of LS-DYNA to Simulate the Water Landing Characteristics of Space Vehicles

    Microsoft Academic Search

    Benjamin A. Tutt; Anthony P. Taylor

    Irvin Aerospace, Inc. has been involved with the recovery\\/landing systems of re-entry and interplanetary space vehicles spanning a number of years. A significant aspect in the assessment of recovery and escape systems is the performance of such vehicles in the event of a water landing. One method used to reduce the loads imparted to the crew as the vehicle enters

  16. Characteristics of soil water soluble organic C and N under different land uses in Alaska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land use conversion induces the quantitative change of soil water soluble organic matter (WSOM). But, knowledge of such change is still limited. In this study, field moist and air dried soils sampled from subarctic Alaska under three land use managements (i. e. forest, agriculture; and grassland c...

  17. In-Soil and Down-Hole Soil Water Sensors: Characteristics for Irrigation Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The past use of soil water sensors for irrigation management was variously hampered by high cost, onerous regulations in the case of the neutron probe (NP), difficulty of installation or maintenance, and poor accuracy. Although many sensors are now available, questions of their utility still abound....

  18. Characteristics of oxygen-18 and deuterium composition in waters from the Pecos River in American Southwest

    Microsoft Academic Search

    Fasong Yuan; Seiichi Miyamoto

    2008-01-01

    The Pecos River, situated in eastern New Mexico and western Texas, receives snowmelt from winter storms in the headwater region of the southern Rocky Mountains and runoff from warm-season monsoonal rainfall in the lower valley. The isotopic composition of the two water sources differs from each other due to their different geographical origins in the Pacific North and the Gulf

  19. Water Quality Characteristics of Three Rain Gardens Located Within the Twin Cities Metropolitan Area, Minnesota

    Microsoft Academic Search

    Sarah Elliott; Mary H. Meyer; Gary R. Sands; Brian Horgan

    2011-01-01

    A study was conducted by the United States Geological Survey (USGS) at three locations in the Twin Cities Metropolitan Area in Minnesota to assess the effect that bioretention areas, or rain gardens, have on water quality. The rain gardens are located at the University of Minnesota Landscape Arboretum (MLA), City of Hugo, and City of Woodbury. These sites were chosen

  20. Water quality characteristics of discharge from reforested loose-dumped mine spoil in eastern Kentucky.

    PubMed

    Agouridis, Carmen T; Angel, Patrick N; Taylor, Timothy J; Barton, Christopher D; Warner, Richard C; Yu, Xia; Wood, Constance

    2012-01-01

    Surface mining is a common method for extracting coal in the coal fields of eastern Kentucky. Using the Forestry Reclamation Approach (FRA), which emphasizes the use of minimally compacted or loose-dumped spoil as a growth medium for trees, reclamation practitioners are successfully reestablishing forests. Yet, questions remain regarding the effects FRA has on the quality of waters discharged to receiving streams. To examine the effect of FRA on water quality, this study compared waters that were discharged from three types of spoils: predominantly brown, weathered sandstone (BROWN); predominantly gray, unweathered sandstone (GRAY); and an equal mixture of both aforementioned sandstones and shale (MIXED). The water quality parameters pH, EC, Ca, K, Mg, Na, NO-N, NH-N, SO, Cl, TC, suspended sediment concentration (SSC), settleable solids (SS), and turbidity were monitored over a 2-yr period on six 0.4-ha plots (two replications per spoil type). Generally, levels of Cl, SO, Ca, NO-N, NH-N, SS, SSC, and turbidity decreased over time. The pH for all spoils increased from about 7.5 to 8.5. The EC remained relatively level in the BROWN spoil, whereas the GRAY and MIXED spoils had downward trajectories that were approaching 500 ?S cm. The value of 500 ?S cm has been reported as the apparent threshold at which certain taxa such as Ephemeroptera (e.g., Mayfly) recolonize disturbed headwater streams of eastern Kentucky and adjacent coal-producing Appalachian states. PMID:22370409