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1

[Water physiological characteristics of four perennial plant species around Cele Oasis in Xinjiang].  

PubMed

The water physiological characteristics of four perennial plant species (Populus euphratica, Tamarix ramosissima, Calligonum caput-medusae, and Alhagi sparsifolia) around Cele Oasis in Xinjiang were studied through their vegetation growth period. No signs of serious drought stress were observed in any of the test perennial species during their vegetation growth, and irrigation had little effects on the water status of the plants (P > 0.05). The seasonal variation characteristics of water physiological parameters differed with the plants. A. sparsifolia had the highest predawn water potential (PWP) and daily mean sap flow, but the lowest mean water use efficiency (WUE); C. caput-medusae had the highest mean WUE, and its PWP and sap flow were stable and had less seasonal change; T. ramosissima had the lowest PWP during its growth, and had better adaptation ability to the environment; and P. euphratica had relatively stable water physiological characteristics during its growth. The four perennial plant species had deep root systems to access underground water to satisfy their large demands for water, and thus, well adapted to the harsh environmental conditions around Cele Oasis. PMID:20135993

Zeng, Fan-Jiang; Li, Xiang-Yi; Zhaneg, Xi-Ming; Foetzki, A; Arndt, S K

2009-11-01

2

[Photosynthetic and water physiological characteristics of weedy rice in northern China].  

PubMed

Weedy rice is an important germplasm source of rice, which has the characteristics of cold-, drought-, and barren tolerance. Taking 88 accessions of weedy rice and 4 varieties of cultivated rice in northern China as test materials, this paper studied the photosynthetic characteristics (photosynthetic rate, transpiration rate, and stomatal conductance), water physiological characteristics, and their interrelationships of weedy rice in northern China. There existed greater differences in the photosynthetic and water physiological characteristics among the weedy rice accessions, possessing abundant diversity. The photosynthetic rate of the accessions was from 12.47 micromol CO2 x m(-2) x s(-1) to 28.67 micromol CO2 X m(-2) x s(-1), and the instantaneous water use efficiency was from 1.39 mg x g(-1) to 3.40 mg x g(-1). Among the photosynthetic parameters, intercellular CO2 concentration had the smallest variable coefficient, while stomatal conductance had the largest one. The photosynthetic rate had significant conic relationships with transpiration rate and stomatal conductance, and had a linear relationship with intercellular CO2 concentration. The significant conic relationships also existed between the instantaneous water use efficiency and the transpiration rate and stomatal conductance. The excellent features of weedy rice could be used to improve the cultivated rice varieties. PMID:24564141

Gao, Qi; Ma, Dian-Rong; Kong, De-Xiu; Wang, Wen-Jia; Tong, Hui; Zhao, Ming-Hui; Xu, Zheng-Jin; Chen, Wen-Fu

2013-11-01

3

[Effects of simulated acid rain on water physiological characteristics of Myrica rubra seedlings].  

PubMed

Taking the seedlings of typical subtropical economic tree species Myrica rubra in Zhejiang Province as test materials, a pot experiment was conducted to study their water physiological characteristics under effects of simulated acid rain (pH 2.5 and pH 4.0), with water (pH 5.6) as the control. Season, year, and acid rain all had significant effects on the photosynthetic rate (Pn). Among the treatments, the Pn had a greater difference in summer than in spring and autumn, and was higher in treatment acid rain (pH 4.0). Season, year, acid rain, and the interactions of season and year and of the three factors had significant effects on the stomata conductance (Gs), and also, the Gs had a greater difference among the treatments in summer than in spring and autumn. Acid rain had inhibitory effect on Gs. Season, year, acid rain, and the interactions of season and year and of season and acid rain affected the transpiration rate (Tr) significantly. Same as Pn and Gs, the Tr had a greater difference among the treatments in summer than in spring and autumn. Acid rain (pH 2.5) had the strongest inhibitory effect on Tr. Acid rain and the interactions of season and year and of season and acid rain had significant effects on the water use efficiency (WUE), and acid rain (pH 2.5) had definitely positive effect on the WUE. PMID:22097355

Yaho, Zhao-bin; Jiang, Hong; Yu, Shu-quan; Lu, Mei-juan

2011-08-01

4

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

PubMed Central

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

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

2014-01-01

5

Physiological characteristics of elite judo athletes.  

PubMed

In order to provide some understanding of the physiological capacities underlying successful judo performance, representative values for a variety of physiological variables were determined in nationally ranked male (n = 18) and female (n = 9) judo athletes. Body composition, aerobic capacity, isokinetic elbow and knee flexor and extensor strength, and muscle fiber size and composition of the vastus lateralis were examined. Comparisons across weight divisions indicate that the values of many characteristics varied as a function of size. As weight division increased, relative VO2 decreased (r = -0.53 and -0.63 for males and females, respectively), % body fat increased (r = 0.64, 0.72), and the cross sectional areas of Type I (r = 0.55, 0.77) and Type IIA (r = 0.47, = 0.76) muscle fibers increased. Among females in particular, athletes in the higher weight divisions were stronger relative to LBM than those in the lower division. These results indicate that the physiological profiles of lower and upper weight division elite judo players differ markedly. It is suggested that the factors responsible for success may be specific to each weight division and may represent a compromise between making weight and maximizing physiological capacities and performance. PMID:1860744

Callister, R; Callister, R J; Staron, R S; Fleck, S J; Tesch, P; Dudley, G A

1991-04-01

6

Impact of human emotions on physiological characteristics  

NASA Astrophysics Data System (ADS)

Emotional states of humans and their impact on physiological and neurological characteristics are discussed in this paper. This problem is the goal of many teams who have dealt with this topic. Nowadays, it is necessary to increase the accuracy of methods for obtaining information about correlations between emotional state and physiological changes. To be able to record these changes, we focused on two majority emotional states. Studied subjects were psychologically stimulated to neutral - calm and then to the stress state. Electrocardiography, Electroencephalography and blood pressure represented neurological and physiological samples that were collected during patient's stimulated conditions. Speech activity was recording during the patient was reading selected text. Feature extraction was calculated by speech processing operations. Classifier based on Gaussian Mixture Model was trained and tested using Mel-Frequency Cepstral Coefficients extracted from the patient's speech. All measurements were performed in a chamber with electromagnetic compatibility. The article discusses a method for determining the influence of stress emotional state on the human and his physiological and neurological changes.

Partila, P.; Voznak, M.; Peterek, T.; Penhaker, M.; Novak, V.; Tovarek, J.; Mehic, Miralem; Vojtech, L.

2014-05-01

7

Physiological characteristics of international female soccer players.  

PubMed

The purpose of this study was to investigate the physiological characteristics of Fédération Internationale de Football Association (FIFA) eligible international female soccer players aged 14-36 years and to determine if measures were significantly different for players selected (i.e., starters) to the starting line up for an FIFA tournament as compared with those not selected (i.e., nonstarters). Fifty-one (N = 18 Under 17; N = 18 Under 20; N = 15 Senior) international female soccer players participated in this study. The subjects underwent measurements of anthropometry (height and body mass), lower body strength (isokinetic testing), sprint kinetics and kinematics (nonmotorized treadmill), leg power (unilateral jumping), and maximal aerobic velocity (30:15 intermittent fitness test) during the final preparatory stage for an FIFA event. Outcomes of the age group data indicate that differences in physiological capacities are evident for the Under 17 players as compared with those for the Under 20 and Senior capped international players, suggesting a plateau in the acquisition of physical qualities as players mature. Starters tended to be faster (effect size [ES] = 0.55-1.0, p < 0.05) and have a higher maximal aerobic velocity (ES = 0.78-2.45, p < 0.05), along with greater eccentric leg strength (ES = 0.33-1.67, p < 0.05). Significant differences were detected between starters and nonstarters for isokinetic leg strength (ES = 0.54-1.24, p < 0.05) and maximal aerobic velocity (ES = 0.87, p < 0.05) for Under 17 players, where maximal aerobic velocity was the primary difference between starters and nonstarters (ES = 0.83-2.45, p < 0.05) for the Under 20 and Senior players. Coaches should emphasize the development of speed, maximal aerobic velocity, and leg strength in developing female soccer players. PMID:24476742

Manson, Sarah A; Brughelli, Matt; Harris, Nigel K

2014-02-01

8

Fish Physiology, Toxicology, and Water Quality  

E-print Network

their sewage into rivers and coastal waters worldwide. This is resulting in eutrophication of rivers and coastal waters everywhere. Eutrophication is associated with elevated ammonia and nitrite levels, bothFish Physiology, Toxicology, and Water Quality Proceedings of the Ninth International

DeWitt, Thomas J.

9

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...

10

Physiological characteristics of America's Cup sailors.  

PubMed

The aim of this study was to assess the physiological profile of America's Cup grinders and mastmen, by measuring energy expenditure during sailing and assessing their aerobic and anaerobic fitness. The study focused on estimating the energy used during grinding activity, by measuring oxygen uptake (VO(2)) during sail setting in real sailing conditions. In the laboratory, using an arm-cranking ergometer, we measured VO(2peak) during an incremental maximal exercise test and total energy expended during the effort and recovery phases of an all-out test that simulated grinding activity, in six grinders and mastmen and ten sailors of the same crew. Total energy used during grinding corresponded to 45% (s = 9) and 51% (s = 5) of that used in the all-out test (234 kJ, s = 21.7) for tacks and gybes, respectively. In both grinding activity and the all-out test, VO(2) increased during and after the effort. The "VO(2) top value" was 53% (s = 8.6), 68% (s = 5.5), and 78% (s = 3.1) of VO(2peak) (4.7 l . min(-1), s = 0.43) in tacks, gybes, and the all-out test, respectively. During fast sequences of grinding activity, the "VO(2) top value" reached 65% (s = 7.1) VO(2peak) in tacks and 91% (s = 3.3) VO(2peak) in gybes. Our results suggest that grinders and mastmen are characterized by a high anaerobic capacity but their performance can be improved by powering aerobic fitness, to increase this energy contribution to all-out efforts and to guarantee fast recovery when grinding activity is repeated with short rest intervals. PMID:17613738

Bernardi, Marco; Quattrini, Filippo M; Rodio, Angelo; Fontana, Giuseppe; Madaffari, Andrea; Brugnoli, Marco; Marchetti, Marco

2007-08-01

11

Aquaporin water channels in gastrointestinal physiology  

PubMed Central

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

Ma, Tonghui; Verkman, A S

1999-01-01

12

Physiological and acoustic characteristics of the female music theater voice  

E-print Network

Physiological and acoustic characteristics of the female music theater voice Tracy Bourne December 2011; accepted 8 December 2011) Three Music Theater vocal qualities ("chesty belt," "twangy belt experienced Music Theater singers performed each quality on two different vowels ([e], [O]). Audio

New South Wales, University of

13

Elite and Nonelite Soccer Players: Preseasonal Physical and Physiological Characteristics  

Microsoft Academic Search

The purpose of this study was to (a) describe physical and functional characteristics of elite Serbian soccer players, and (b) make comparisons with nonelite counterparts to identify any relationships between results from the physiological tests and competition level. One of the teams in the study (Squad A; nA = 30) competed in the professional First National League, and the other

SERGEJ M. OSTOJIC

2004-01-01

14

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

Microsoft Academic Search

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

Katsunori Tanaka; Yoshiko Kosugi; Akihiro Nakamura

2002-01-01

15

Anthropometric and physiological characteristics of junior elite volleyball players  

PubMed Central

Objectives To investigate the anthropometric and physiological characteristics of junior elite volleyball players. Method Twenty five national level volleyball players (mean (SD) age 17.5 (0.5) years) were assessed on a number of physiological and anthropometric variables. Somatotype was assessed using the Heath?Carter method, body composition (% body fat, % muscle mass) was assessed using surface anthropometry, leg strength was assessed using a leg and back dynamometer, low back and hamstring flexibility was assessed using the sit and reach test, and the vertical jump was used as a measure of lower body power. Maximal oxygen uptake was predicted using the 20?m multistage fitness test. Results Setters were more ectomorphic (p<0.05) and less mesomorphic (p<0.01) than centres. Mean (SD) of somatotype (endomorphy, mesomorphy, ectomorphy) for setters and centres was 2.6 (0.9), 1.9 (1.1), 5.3 (1.2) and 2.2 (0.8), 3.9 (1.1), 3.6 (0.7) respectively. Hitters had significantly greater low back and hamstring flexibility than opposites. Mean (SD) for sit and reach was 19.3 (8.3)?cm for opposites and 37 (10.7)?cm for hitters. There were no other significant differences in physiological and anthropometric variables across playing positions (all p>0.05). Conclusion Setters tend to be endomorphic ectomorphs, hitters and opposites tend to be balanced ectomorphs, whereas centres tend to be ectomorphic mesomorphs. These results indicate the need for sports scientists and conditioning professionals to take the body type of volleyball players into account when designing individualised position specific training programmes. PMID:16799112

Duncan, M J; Woodfield, L; al-Nakeeb, Y

2006-01-01

16

THE PHYSIOLOGICAL EFFECTS OF WATER vs. GATORADE DURING PROLONGED EXERCISE  

Microsoft Academic Search

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

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

17

Tolerance and physiological responses of Phragmites australis to water deficit  

E-print Network

Tolerance and physiological responses of Phragmites australis to water deficit Majken Pagter in revised form 19 November 2004; accepted 3 January 2005 Abstract The water stress tolerance of Phragmites australis (Cav.) Trin ex. Steud. grown in the laboratory were investigated by examining effects of different

Brix, Hans

18

Water Chemistry Alters Gene Expression and Physiological End  

E-print Network

Water Chemistry Alters Gene Expression and Physiological End Points of Chronic Waterborne Copper to ascertainbothtranscriptionalandfunctionalendpointsofchronic Cu toxicity in fish associated with experimentally manipulated water chemistries. Over 21 d to the following: soft-water (Ctrl); 12 µg L-1 Cu (Cu); 3.3 mM Na+ (Na); 3.3 mM Na+ + 12 µg L-1 Cu (Na + Cu); 3.3 m

McClelland, Grant B.

19

The Clinical Physiology of Water Metabolism  

PubMed Central

The renal reabsorption of water independent of solute is the result of the coordinated function of the collecting duct and the ascending limb of the loop of Henle. The unique juxtaposition of the ascending and descending portions of the loop of Henle and of the vasa recta permits the function of a counter-current multiplier system in which water is removed from the tubular lumen and reabsorbed into the circulation. The driving force for reabsorption is the osmotic gradient in the renal medulla which is dependent, in part, on chloride (followed by sodium) pumping from the thick ascending loop of Henle. Urea trapping is also thought to play an important role in the generation of a hypertonic medullary interstitium. Arginine vasopressin (AVP) acts by binding to receptors on the cell membrane and activating adenylate cyclase. This, inturn, results in the intracellular accumulation of cyclic adenosine monophosphate (AMP) which in some fashion abruptly increases the water permeability of the luminal membrane of cells in the collecting duct. As a consequence, water flows along an osmotic gradient out of the tubular lumen into the medullary interstitium. Diabetes insipidus is the clinical condition associated with either a deficiency of or a resistance to AVP. Central diabetes insipidus is due to diminished release of AVP following damage to either the neurosecretory nuclei or the pituitary stalk. Possible causes include idiopathic, familial, trauma, tumor, infection or vascular lesions. Patients present with polyuria, usually beginning over a period of a few days. The diagnosis is made by showing that urinary concentration is impaired after water restriction but that there is a good response to exogenous vasopressin therapy. Nephrogenic diabetes insipidus can be identified by a patient's lack of response to AVP. Nephrogenic diabetes insipidus is caused by a familial defect, although milder forms can be acquired as a result of various forms of renal disease. Central diabetes insipidus is eminently responsive to replacement therapy, particularly with dDAVP, a long lasting analogue of AVP. Nephrogenic diabetes insipidus is best treated with a combination of thiazide diuretics as well as a diet low in sodium and protein. ImagesFigure 27.Figure 31. PMID:545867

Weitzman, Richard E.; Kleeman, Charles R.

1979-01-01

20

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...

21

Physiological Effects of Trace Elements and Chemicals in Water  

ERIC Educational Resources Information Center

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.…

Varma, M. M.; And Others

1976-01-01

22

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

PubMed

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

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

1997-03-01

23

[Anatomic, physiological and metabolic characteristics of young athletes].  

PubMed

A rational approach to the organization of the training process, the competitive cycle, the recovery processes in the practice of child and youth sport requires knowledge of the anatomical and physiological characteristics of the organism in these age periods. Exchange of amino acids in children of 6 to 12 years takes place very actively providing processes of growth and development. The children of preschool and early school age have tendency to hypoglycemia due to the imperfection of neurohumoral regulation of the mobilization of glycogen in the liver and increased utilization of glucose. Glucose utilization corresponds to its level in adults, ranging from 8 to 14 years of age. In children under the age of 10 an increased tendency to the formation of ketone bodies and ketosis is determined. Cholesterol levels increase rapidly after birth. From the period of puberty, girls have higher levels of total cholesterol, cholesterol in low density lipoprotein (LDL) and high density lipoproteins (HDL) than boys. At the age of 6-12 years basal metabolic rate decreases to 1.3-1.5 kcal/kg/h. The muscular system increasingly develops. Functional features of the central nervous system is the predominance of excitation. Sympathetic part of the autonomic nervous system prevails in heart's activity. The role of the hypothalamic-pituitary system significantly increases in the structure of the endocrine glands. The sensitivity of many endocrine glands to the tropic hormone produced in the adenohypophysis increases. At the age of 8-12 years the role of epinephrine, norepinephrine and other biogenic amines especially increases. Period of puberty at the age of 13-17 years is associated with a significant change in the hormonal status of the organism. A pubertal growth spurt takes place, which occurs 1-2 years earlier in girls than in boys. As for the skeletal system the most pronounced growth of tubular bones of the limbs, spine and increase of bone density, muscle mass occurs. Heart rate decreases, while the duration of the expulsion phase of blood, cardiac output, respiratory functional parameters and red blood cells and hemoglobin concentrations increase. Endurance rises, physical activity is more economical than in childhood. PMID:24741954

Nikitiuk, D B; Korosteleva, M M; Volkova, L Iu

2013-01-01

24

[Effects of shading on squash seedlings' morphological and photosynthetic physiological characteristics].  

PubMed

The study of squash seedlings' morphological and photosynthetic physiological characteristics under different shading showed that under 60% light transmittance, their relative growth rate, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (EVAP), water use efficiency (WUE), saturation steam pressure (MBR), apparent quantum yield of photosynthesis (AQY), and chlorophyll contents were higher, while the intercellular CO2 concentration (Ci) was lower, compared with those under 20% light transmittance and CK. The seedlings under 60% light transmittance had a higher light saturation point (1 125 micromol x m(-2) x s(-1)) but a lower light compensation point (15.2 micromol x m(-2) s(-1)). Squash seedlings under lower light intensity could endure lower concentration of CO2, while those under higher light intensity could endure higher concentration of CO2. Under 60% light transmittance, the malondialdehyde (MDA) and praline (Pro) contents were the lowest, while the peroxidase (POD) and catalase (CAT) activities were the highest. PMID:16836096

Qin, Shuhao; Li, Lingling

2006-04-01

25

Crop Physiology  

SciTech Connect

In this chapter, we review the physiology of switchgrass from seed dormancy till the effects of water and nutrients stress on grown plants. These characteristics are presented and discussed mainly at the canopy and whole-plant level with emphasis on the agro-physiology of the species in view of the possible contribution of crop physiology to agricultural development. Switchgrass is noted for the variable degrees of seed dormancy regulated by endogenous and exogenous factors that determine the successful seedling establishment. Plant growth rates are determined by temperature while the reproductive phase is controlled mainly by photoperiod. There is also evidence that some physiological attributes, such as photosynthesis, transpiration, and water use efficiency differ between tetraploid, hexaploid and octaploid ecotypes. But despite these differences, in general switchgrass combines important attributes of efficient use of nutrients and water with high yields thanks to its ability to acquire resources from extended soil volumes, especially at deep layers. Moreover at canopy level, resources capture and conservation are determined by morpho-physiological characteristics (C{sub 4} photosynthetic pathway, stomatal control of transpiration, high leaf area index, low light extinction coefficient) that enhance radiation use efficiency and reduce carbon losses. However, specific information on switchgrass physiology is still missing, in particular deeper understanding of physiological principles controlling the water and nutrients acquisition mechanisms and allocation under suboptimal growing conditions. The physiology of tillering and root respiration are also factors that need further investigation.

Zegada-Lizarazu, Walter [University of Bologna; Wullschleger, Stan D [ORNL; Nair, S. Surendran [University of Tennessee, Knoxville (UTK); Monti, Andrea [University of Bologna

2013-01-01

26

Relationship between anthropometric and physiological characteristics in youth soccer players.  

PubMed

This study examined the relationship between anthropometric and physiological performances among youth soccer players and the positional differences for these variables. Seventy U14 male soccer players (goalkeeper: 10, defender: 20, midfielder: 25, and forward: 15) participated in this study. Body mass was significantly (p < 0.05) correlated with ball shooting speed (r = 0.58) and 30 m sprint time (r = -0.54). Body height was significantly (p < 0.05) correlated with vertical jump height (r = 0.36), 10 m (r = -0.32) and 30 m (r = -0.64) sprint times, Yo-Yo intermittent endurance run (YYIER) distance (r = 0.26), and running time during maximal oxygen uptake (Vo2max) (r = 0.35). Body mass index (BMI) was significantly (p < 0.05) correlated with ball shooting speed (r = 0.31), 30 m sprint time (r = -0.24), Hoff test dribble distance (r = -0.29), YYIER distance (r = -0.25), submaximal running cost (r = -0.38), Vo2max (r = -0.42), and the corresponding running time (r = -0.24). Significant positional differences were observed in anthropometry (body mass [p < 0.01], height [p < 0.01], and BMI [p < 0.01]) but not in physiological performances. This study provides a scientific rationale behind the coaches' practice of selecting young soccer players according to their anthropometry for short-term benefits such as heavier players for higher ball shooting speed and 30-m sprint ability as an example. However, this does not justify such practice in the long-term process of player development. PMID:19528844

Wong, Pui-Lam; Chamari, Karim; Dellal, Alexandre; Wisløff, Ulrik

2009-07-01

27

[Anthropometric and physiological characteristics of Puerto Rican cyclists].  

PubMed

This study was conducted to describe various anthropometric, body composition, cardiorespiratory, metabolic and neuromuscular characteristics of 31 athletes (F = 5, M = 26) members of the Puertorrican Cycling Federation's national pre-selection. The athletes were divided into four categories according to their sex and age. The mean and standard deviation of all the variables in each category was computed. An Analysis of Covariance was conducted to determine significant differences between the mean's of the four categories. Male cyclists showed superior results compared to female cyclists in all the variables studied except body mass, ectomorphy, VO2 max, max HR, max power (W), and neuromuscular function in which they showed no statistical differences. The anthropometric, body composition, max power (W) and cardiorespiratory characteristics of our cyclists compared with those reported for international cyclists. The groups means for push ups, sit ups and flexibility were below the excellent classification when compared to the general population's health related physical fitness norms. PMID:1475344

Ramírez Marrero, F A; Rivera, M A

1992-12-01

28

Physiological characteristics of elite dancers of different dance styles.  

PubMed

The present investigation was aimed to study international level dancesport dancer's aerobic capacity during incremental test and competition simulation in relation to the gender, dance style and international ranking. A total of 30 couples (12 Standard, 7 Latin American and 11 Ten Dance; aged 22.8 ± 6.6 years male and 22.0 ± 6.4 years female) performed an incremental treadmill test and competition simulation. In this study for the first time we carried out longer than one round competition simulation and compared three different dancesport styles (Standard, Latin American and Ten Dance). The results showed that dancers of these three dance styles had similar aerobic capacity values. The average maximal oxygen consumption (VO2max) values were 59.6 ± 5.1 and 51.2 ± 6.2 ml · min(-1) · kg(-1) for male and female dancers, respectively. Competition simulation showed that Latin American Dance discipline is physiologically more intensive compared to Standard and Ten Dance styles especially for the female dancers. It appeared that male and female Standard dancers tended to perform at lower intensity than anaerobic threshold (AT) during competition simulation (male 97.3 ± 2.9%; female 97.9 ± 3.6%), while Latin (male 101.4 ± 2.9%; female 106.7 ± 5.9%) and Ten Dance (male 100.7 ± 6.4%; female 99.2 ± 5.6%) competition intensity was higher compared to AT level of athletes. The highest heart rate during competition simulation was always found during the last dances (Paso Double, Jive or Quickstep) and in the last round of each dance style. No significant relationship between VO2max values and international rankings was registered. PMID:24444238

Liiv, Helena; Jürimäe, Toivo; Mäestu, Jarek; Purge, Priit; Hannus, Aave; Jürimäe, Jaak

2014-01-01

29

The cadence and water temperature effect on physiological responses during water cycling.  

PubMed

The aim of the study was to compare the maximal physiological responses during three protocols: maximal test on land cycle ergometer, maximal test on water cycling in an indoor pool at 27 °C (WC27) and at 31 °C (WC31). Moreover, the submaximal physiological responses were compared according cycling cadences and water temperatures during the water protocols. Ten young men were included and performed the protocols in separate days. Blood lactate (BL) concentration, heart rate (HR), oxygen uptake (VO2), ventilation (VE) and thermal comfort (TC) were collected during the exercise. The maximal HR and VO2 showed no significant differences between the protocols: HRmax: 189 ± 7 (Land), 188 ± 14 (WC27), 185 ± 9 bpm (WC31) and VO2max: 4.2 ± 0.4 (Land), 4.1 ± 0.5 (WC27) and 4.3 ± 0.5 l min(-1) (WC31). However, the maximal BL demonstrated significant lower values during the water protocols compared to the land protocol (p=0.018). All the submaximal physiological responses showed significant differences between the cadences (60, 70, 80 and 90 rpm). The effect of water temperature was significant for TC response (p=0.001) showing higher values at 31 °C than 27 °C (TCW27: 7 ± 1 and TCW31:9 ± 1). In conclusion, higher physiological responses were showed by increasing the cadence by 10 rpm and the subjects were more comfortable when cycling in the lower water temperature. PMID:24175730

Yazigi, Flávia; Pinto, Stephanie; Colado, Juan; Escalante, Yolanda; Armada-da-Silva, Paulo A S; Brasil, Roxana; Alves, Francisco

2013-01-01

30

Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.  

PubMed

Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water. PMID:23819294

Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

2013-01-01

31

Physical and Chemical Water Characteristics  

Microsoft Academic Search

An outline is given of the physical and chemical features of waters in the Nile system, including headwater lakes. Temperature\\u000a is governed by the large range of latitude and altitude, and is mostly within 15–30°C. Differences with depth can be appreciable\\u000a under conditions of low to minimal flow and in deeper water columns. They introduce a density stratification with both

Jack F. Talling

32

PHYSIOLOGICAL ECOLOGY -ORIGINAL PAPER Patterns of Tamarix water use during a record drought  

E-print Network

and physiological responses of the invasive riparian shrub Tamarix ramosissima. In early May, diel water table flucPHYSIOLOGICAL ECOLOGY - ORIGINAL PAPER Patterns of Tamarix water use during a record drought Jesse uptake by Tamarix or other non-senesced species from a deeper water table later in the growing season

Nippert, Jesse

33

Thermal characteristics of running waters  

Microsoft Academic Search

This chapter reviews available data on thermal conditions prevailing in lotic ecosystems of the Southern Hemisphere. The primary factors (hydrology, climate, insolation) that interact to determine the thermal régime are examined in the context of southern waters. Maximum temperatures are plotted against annual ranges for equatorial (0–10° latitude), tropical (10–231\\/2° latitude), and temperate sites. In regions with seasonal climates, running

J. V. Ward

1985-01-01

34

Flow characteristics of water in microtubes  

Microsoft Academic Search

Water flow through microtubes with diameters ranging from 50 to 254 ?m was investigated experimentally. Microtubes of fused silica (FS) and stainless steel (SS) were used. Pressure drop and flow rates were measured to analyze the flow characteristics. The experimental results indicate significant departure of flow characteristics from the predictions of the conventional theory for microtubes with smaller diameters. For

Gh. Mohiuddin Mala; Dongqing Li

1999-01-01

35

Influence of Morphological Characteristics on Physical and Physiological Performances of Tunisian Elite Male Handball Players  

PubMed Central

Purpose The purpose of this study was to describe the body structure and morphological characteristics of Tunisian elite handball players, and to determine the effect of these variables on functional and physical performance levels. Methods A sample of 42 male handball players (mean age 21.98±3.24 years; training duration 12 years) at international level was submitted to a test battery comprising morphological, physical and physiological assessments. Tests were yo-yo intermittent recovery test, squat jump test, countermovement jump test, vertical-jump test, and Repeated sprint Ability. Measures for assessment of anthropometric characteristics were age, size, weight, body mass index, body fat, fat mass and thin mass. Results Weight was negatively correlated to the squat jump and the countermovement jump performance. Age, weight, and body composition measures (fat and thin body mass) were additionally negatively related to the maximal oxygen uptake, and to the maximal velocity obtained in the Yo-Yo recovery test. No relationship was found between size, body mass index, body fat and the physical abilities considered. Concerning the effects of physical characteristics on the functional performances, we can note a positive relationship between squat jump, countermovement jump, and the yo-yo recovery test performance. No relationship was found between vertical jump, repeated sprint ability, and the physiological performances. Conclusions Study results point to the existence of strong correlation between morphological and physical characteristics with functional characteristics. In handball, it is possible to have a reliable estimate of anthropometric measurements, physical and physiological performances. PMID:22942992

Moncef, Cherif; Said, Mohamed; Olfa, Najlaoui; Dagbaji, Gomri

2012-01-01

36

Comparative Biochemistry and Physiology Part A 127 (2000) 8187 Effects of acute fresh water exposure on water flux rates  

E-print Network

Comparative Biochemistry and Physiology Part A 127 (2000) 81­87 Effects of acute fresh water to fresh water were quantified. Salt-water adapted turtles were exposed to fresh water for 4 d before being.290.1 l d-1 and 123.096.8 ml kg-1 d-1 , respectively. When turtles were exposed to fresh water, rates

Ortiz, Rudy M.

37

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

38

Ozonation characteristics of bisphenol a in water  

Microsoft Academic Search

Ozonation characteristics of bisphenol A were investigated as a function of gaseous ozone dose, initial concentration of bisphenol A, pH, radical scavenger (tert?butanol), and radical initiator (hydrogen peroxide). The ozonation led to a complete removal of bisphenol A in water within a certain period of time. The overall rate of the ozonation linearly increased with the ozone dose. The stoichiometry

J. Lee; J. Yoon

2003-01-01

39

Physiological, Behavioral, and Dietary Characteristics Associated with Hypertension among Kenyan Defence Forces  

PubMed Central

Background. Hypertensive disease is increasing in developing countries due to nutritional transition and westernization. Hypertensive disease among Kenya military may be lower because of health-focused recruitment, physical activities, routine checkups, and health awareness and management, but the disease has been increasing. Purpose. The purpose of this study was to determine physiological, behavioral, and dietary characteristics associated with hypertension among Kenyan military. Methods. A cross-sectional study involving 340 participants was conducted at Armed Forces Memorial Hospital. Participants' history, risk factors assessment, and dietary patterns were obtained by structured questionnaire, while physiological and anthropometric parameters were measured. Results. Hypertensive participants were likely to have higher age, physiological, and anthropometric measurements, and they participated in peace missions. Daily alcohol and smoking, frequent red meat, and inadequate fruits and vegetables were associated with hypertension. Conclusions. The findings mimic the main risk factors and characteristics for hypertensive disease in developed countries whose lifestyle adoption is happening fast in low and middle-income countries. Whether or not prediction rules and/or risk scores may identify at-risk individuals for preventive strategy for targeted behavioral interventions among this population require investigation. PMID:24977096

Mundan, Victor; Muiva, Margaret; Kimani, Samuel

2013-01-01

40

Effect of a one-semester conditioning class on physiological characteristics of college students.  

PubMed

Danoff, JV and Raupers, EG. Effect of a one-semester conditioning class on physiological characteristics of college students. J Strength Cond Res 28(11): 3120-3125, 2014-Long-term exercise is known to have positive effects on the health of adults. Some college "activity" courses are designed to give participants exposure to, and practice with, safe exercise techniques. Whether these 1-semester courses, usually 12-14 weeks, are sufficient to alter physiological characteristics, such as blood pressure or strength, has not been established. Therefore, the purpose of our investigation was to evaluate physiological and performance measures in college students to determine whether changes would result after 14 weeks of a general conditioning activity course. This study involved 79 students from several sections of exercise and conditioning classes at our university. Classes included a variety of fitness- and strength-oriented exercises. Physiological and performance measurements were collected in weeks 2 (pretest) and 14 (posttest), and compared pre with post using paired t-tests subject to Bonferroni correction (significant p < 0.0055). There were significant improvements in resting heart rate (HR) (73 vs. 70 b·min, p < 0.002), hand grip strength (250 vs. 272 N, p < 0.001), push-ups (29 vs 37, p < 0.001), sit-ups (32 vs. 35, p < 0.001), and step test HR recovery (122 vs. 110 b·min, p < 0.001). Systolic and diastolic blood pressures, body weight, and percent body fat did not change. These results suggest that 14 weeks of regular exercise in an organized college-based activity class can result in significant improvements in some measures of fitness and strength in college-aged participants. PMID:25264668

Danoff, Jerome V; Raupers, Erin G

2014-11-01

41

FISH PHYSIOLOGY, TOXICOLOGY AND WATER QUALITY MANAGEMENT: PROCEEDINGS OF 3RD BIENNIAL INTERNATIONAL SYMPOSIUM, NANJING, PRC  

EPA Science Inventory

Scientists from four countries presented papers at the Third Biennial International Symposium on Fish Physiology, Toxicology and Water Quality Management, which was held on the campus of Nanjing University, Nanjing, Jiangsu Province, People's Republic of China. his proceedings in...

42

Physiological and genetic control of water stress tolerance in zoysiagrass  

E-print Network

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 tolerant, had the most...

Dewey, Daniel Wade

2006-04-12

43

Genetic and physiological controls of growth under water deficit.  

PubMed

The sensitivity of expansive growth to water deficit has a large genetic variability, which is higher than that of photosynthesis. It is observed in several species, with some genotypes stopping growth in a relatively wet soil, whereas others continue growing until the lower limit of soil-available water. The responses of growth to soil water deficit and evaporative demand share an appreciable part of their genetic control through the colocation of quantitative trait loci as do the responses of the growth of different organs to water deficit. This result may be caused by common mechanisms of action discussed in this paper (particularly, plant hydraulic properties). We propose that expansive growth, putatively linked to hydraulic processes, determines the sink strength under water deficit, whereas photosynthesis determines source strength. These findings have large consequences for plant modeling under water deficit and for the design of breeding programs. PMID:24569846

Tardieu, François; Parent, Boris; Caldeira, Cecilio F; Welcker, Claude

2014-04-01

44

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

Microsoft Academic Search

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

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

2005-01-01

45

Physiological applications for determining water use efficiency among cotton genotypes  

E-print Network

Drought stress can substantially alter plant metabolism by decreasing plant growth and photosynthesis. The lack of rapid and reliable screening criteria and measurement techniques for determining water use efficiency (WUE) of crop plants has greatly...

Bynum, Joshua Brian

2009-05-15

46

PHYSIOLOGICAL ECOLOGY -ORIGINAL PAPER Drinking water boosts food intake rate, body mass increase  

E-print Network

PHYSIOLOGICAL ECOLOGY - ORIGINAL PAPER Drinking water boosts food intake rate, body mass increase migratory flight in the autumn and has recently been determined to be constrained by availability in which we tested the hypotheses that drinking water increases food use by easing limitations on the birds

Nathan, Ran

47

Differential physiological effects during tonic painful hand immersion tests using hot and ice water  

Microsoft Academic Search

The cold pressor test (CPT) is an empirically validated test commonly used in research on stress, pain and cardiovascular reactivity. Surprisingly, the equivalent test with water heated to noxious temperatures (hot water immersion test, HIT) has not been thoroughly investigated. The aim of the present study was to characterize the physiological effects and psychophysics of both tests and to analyze

Anouk Streff; Linn K. Kuehl; Gilles Michaux; Fernand Anton

2010-01-01

48

Anthropometric and physiological characteristics in young afro-Caribbean swimmers. A preliminary study.  

PubMed

The authors investigated the anthropometric and physiological characteristics of young Guadeloupian competitive swimmers in relation to swimming performance and compared the abilities of these children with those of the young white swimmers reported in the literature. All 2004 competitive swimmers between 10 and 14 y old (126 children, 61 boys and 65 girls, 12.0 ± 1.3 y) from Guadeloupe underwent anthropometric measurements and physiological and performance testing. Six boys on the French national swimming team are referred to hereafter as the 2011 elite subgroup. Anthropometric parameters, a jump-and-reach test, glide, and estimated aerobic power (eVO2max) were assessed in terms of swimming-performance analysis through a 400-m test. This study demonstrated that the Guadeloupian swimmers had more body fat than most age-matched white swimmers but had very poor hydrostatic lift; they had higher peak jump height and they swam as well as their white counterparts. The variability in 400-m performance between subjects was best described by glide, age, and eVO2max. Compared with the group of boys with the same age, the 2011 elite subgroup was significantly better for arm span, peak jump height, glide, and 400-m and 15-m performances. Further research is needed to investigate motor organization and energy cost of swimming in Afro-Caribbean swimmers. PMID:23006763

Hue, Olivier; Antoine-Jonville, Sophie; Galy, Olivier; Blonc, Stephen

2013-05-01

49

[Adaptation of Mycoplasma gallisepticum to unfavorable growth conditions: changes in morphological and physiological characteristics].  

PubMed

Adaptation of Mycoplasma gallisepticum to unfavorable growth conditions results in altered morphological and physiological characteristics of the cells. M. gallisepticum populations in a complete nutrient medium contain pear-shaped vegetative cells (d approximately 0.3 microm; l approximately 0.8 microm) with pronounced polar and cytoskeleton-like structures. Such mycoplasma cells are able to induce damage in a bacterial genome, causing an SOS response of the test strain (Escherichia coli PQ37). In a starvation medium, M. gallisepticum produces nanoforms, small coccoid cells (d approximately 0.15-0.2 microm) without either polar or cytoskeleton-like structures. Unlike vegetative cells, nanoforms do not induce genome damage. Alleviation of unfavorable growth conditions results in a reversion of nanoforms to typical vegetative cells. PMID:19137716

Chernov, V M; Chernova, O A; Gorshkov, O V; Muzykantov, A A; Sha?mardarova, G F; Pel'nikevich, A D; Margulis, A B; Kolpakov, A I; Il'inskaia, O N

2008-01-01

50

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

PubMed

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

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

2005-02-01

51

[Anatomical and water physiological plasticity of Grewia biloba var. parviflora leaf and secondary xylem].  

PubMed

Based on the anatomical observations of leaf and secondary xylem as well as the measurements of leaf water physiological parameters, this paper studied the anatomical and water physiological plasticity of Grewia biloba var. parviflora growing in different succession stage communities. The results showed that G. biloba var. parviflora leaf was characterized by thin bifacial with thin cuticle and few stoma, indicating that it was mesophyte anatomically, while the secondary xylem had typical xeromorphic traits, such as short and thin vessel, high vessel frequency, low percentage single pores, and short fibers and rays. G. biloba var. parviflora had high plasticity in the anatomical structure and water physiological features of leaf and secondary xylem, and the plasticity index was in the order of secondary xylem anatomical structure (0. 24) > water physiological traits (0. 19) > leaf anatomical structure (0. 18). Compared with those growing in mixed forest and Platycladus orientalis forest, the individuals of G. biloba var. parviflora in shrub communities had the xeromorphic traits in the aspects of (1) their secondary xylem had shorter vessel elements, higher vessel frequency, less single porous percentage, lower rays, higher relative conductivity and lower vulnerability index, and (2) their leaf had lower water potential, lower water content and free water content, higher bound water content, high ratio of bound to free water content, and less specific leaf area. The phenotypic plasticity, both anatomical and physiological, made G. biloba var. parviflora tolerate to the drought at earlier succession stages and better adapt to the mesophytic condition at later stages, and consequently, become a widely distributed and dominant species in mixed forests. PMID:17209373

Shi, Gangrong; Cheng, Xuelian; Liu, Lei; Ma, Chengcang

2006-10-01

52

The normal and pathological physiology of brain water.  

PubMed

The physicochemical properties of water enable it to act as a solvent for electrolytes, and to influence the molecular configuration and hence the function--enzymatic in particular--of polypeptide chains in biological systems. The association of water with electrolytes determines the osmotic regulation of cell volume and allows the establishment of the transmembrane ion concentration gradients that underlie nerve excitation and impulse conduction. Fluid in the central nervous system is distributed in the intracellular and extracellular spaces (ICS, ECS) of the brain parenchyma, the cerebrospinal fluid, and the vascular compartment--the brain capillaries and small arteries and veins. Regulated exchange of fluid between these various compartments occurs at the blood-brain barrier (BBB), and at the ventricular ependyma and choroid plexus, and, on the brain surface, at the pia mater. The normal BBB is relatively permeable to water, but considerably less so to ions, including the principal electrolytes Brain fluid regulation takes place within the context of systemic fluid volume control, which depends on the mutual interaction of osmo-, volume-, and pressure-receptors in the hypothalamus, heart and kidney, hormones such as vasopressin, renin-angiotensin, aldosterone, atriopeptins, and digitalis-like immunoreactive substance, and their respective sites of action. Evidence for specific transport capabilities of the cerebral capillary endothelium, for example high Na+K(+)-ATPase activity and the presence at the abluminal surface of a Na(+)--H+ antiporter, suggests that cerebral microvessels play a more active part in brain volume regulation and ion homoeostasis than do capillaries in other vascular beds. The normal brain ECS amounts to 12-19% of brain volume, and is markedly reduced in anoxia, ischaemia, metabolic poisoning, spreading depression, and conventional procedures for histological fixation. The asymmetrical distributions of Na+ K+ and Ca2+ between ICS and ECS underlie the roles of these cations in nerve excitation and conduction, and in signal transduction. The relatively large volume of the CSF, and extensive diffusional exchange of many substances between brain ECS and CSF, augment the ion-homeostasing capacity of the ECS. The choroid plexus, in addition to secreting CSF principally by biochemical mechanisms (there is an additional small component from the extracellular fluid), actively transports some substances from the blood (e.g. nucleotides and ascorbic acid), and actively removes others from the CSF. In contrast with CSF secretion, CSF reabsorption is principally a biomechanical process, passively dependent on the CSF-dural sinus pressure gradient. Pathological increases in intracranial water content imply development of an intracranial mass lesion. The additional water may be distributed diffusely within the brain parenchyma as brain oedema, as a cyst, or as increase in ventricular volume due to hydrocephalus. Brain oedema is classified on the basis of pathophysiology into four categories, vasogenic, cytotoxic, osmotic and hydrostatic. The clinical conditions in which brain oedema presents the greatest problems are tumour, ischaemia, and head injury. Peritumoural oedema is predominantly vasogenic and related to BBB dysfunction. Ischaemic oedema is initially cytotoxic, with a shift of Na+ and CI- ions from ECS to ICS, followed by osmotically obliged water, this shift can be detected by diffusion-weighted MRI. Later in the evolution of an ischaemic lesion the oedema becomes vasogenic, with disruption of the BBB. Recent imaging studies in patients with head injury suggest that the development of traumatic brain oedema may follow a biphasic time course similar to that of ischaemic oedema. Hydrocephalus is associated in the great majority of cases with an obstruction to the circulation or drainage of CSF, or, occasionally, with overproduction of CSF by a choroid plexus papilloma. In either case, the consequence is a ris PMID:9075471

Go, K G

1997-01-01

53

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

SciTech Connect

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.

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

2012-01-01

54

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

Microsoft Academic Search

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.

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

2003-01-01

55

Effects of planting densities on water quality improvements and Pontederia cordata's physiology.  

PubMed

Various planting densities (5, 10, or 20 plants per tank) of Pontederia cordata were water-cultivated in purifying tanks to treat polluted water. Seasonal effects of the planting densities on the water quality improvement and the morphology and physiology of the plant were analyzed. Results indicated that planting densities affected the nitrogen and phosphorus removal of water, and the morphology and physiology of plants, including activity of peroxidise and catalase, content of chlorophyll and soluble protein (SP), the length of root, stem and leaf, tiller number and root density. When planting density increased from 10 to 20 plants per tank, the morphology and physiology of plants, and the nitrogen and phosphorus removal by plants improved slowly, but caused a tiller number decline in individual plants. This variation was significant in autumn, and associated with seasonal variations of plant physiology. During autumn, there were 26 tillers in each plant with 10 plants per tank, compared to 14 tillers per plant with 20 plants per tank. Increase in the nitrogen and phosphorus contents of the plants for 5-10 plants per tank was 5.41 and 0.79 g kg(-1), compared to 1.17 and 0.12 g kg(-1) for 10-20 plants per tank, respectively. PMID:24912229

Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun

2014-01-01

56

[Effects of light quality on rice seedlings growth and physiological characteristics].  

PubMed

By using light emitting diode (LED) to accurately modulate spectral energy distribution, and with fluorescent light as the control, this paper studied the effects of light quality on the seedlings growth and physiological characteristics of rice cultivars 'Wuyunjing 7' and 'Kangyou 63'. Light quality had significant effects on the seedlings growth, and there existed differences at different growth stages. Blue LED inhibited the height growth significantly, and increased the leaf soluble protein content of 'Wuyunjing 7' and the healthy index of the two rice cultivars at five-leaf stage. Red LED increased the stem diameter and healthy index at three-leaf stage and the leaf soluble sugar and starch contents at five-leaf stage significantly. Red-blue LED increased the root number, stem diameter, healthy index, root activity, and root soluble sugar content at three-leaf stage and the fresh mass, dry mass, healthy index, and leaf soluble sugar and sucrose contents at five-leaf stage significantly. Yellow LED increased the plant height and leaf pigment content at initial growth stage. Overall, red-blue LED was more beneficial to the culture of strong rice seedlings. PMID:21941749

Guo, Yin-Sheng; Gu, Ai-Su; Cui, Jin

2011-06-01

57

Effects of low-intensity microwave radiation on Tribolium castaneum physiological and biochemical characteristics and survival.  

PubMed

The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae) is a widespread pest that lives in, and feeds on, wheat flour. Here, we studied the effects of low-intensity microwave radiation (LIMR; physiological and biochemical characteristics of T. castaneum, and compared them to the effects of heat conduction treatment, to provide a theoretical basis for using LIMR for pest control. Lethal model equations with respect to temperature were shown to provide acceptable fitting accuracy for the effects of LIMR treatment. Semi-lethal and lethal temperatures induced through LIMR (48 degrees C and 50 degrees C, respectively) for T. castaneum were lower than those induced through heat conduction (50 degrees C and 52 degrees C). When T. castaneum were subjected to LIMR, the insects' moisture content, pH values, alkaline phosphatase and acetyl cholinesterase activity were all lower than when the insects were subjected to heat conduction. Peroxide values and total free amino acid content were higher, and protein subunits molecular weights were lower when T. castaneum were exposed to LIMR than to heat; moreover, after LIMR exposure, the amino acid composition of T. castaneum was changed and the insect's DNA was damaged. PMID:20438733

Lu, Huanghua; Zhou, Jicheng; Xiong, Shanbai; Zhao, Siming

2010-09-01

58

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

PubMed

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

Wang, Dahui; Yu, Xiaoliu; Gongyuan, Wei

2013-09-01

59

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

PubMed

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

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

2010-01-01

60

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

PubMed Central

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

2010-01-01

61

[Effects of allelochemicals ethyl cinnamate on the growth and physiological characteristics of Chlorella pyrenoidosa].  

PubMed

The effects of ethyl cinnamate on the growth and physiological characteristics of Chlorella pyrenoidosa were studied. The allelopathic mechanisms were explored, from views of chlorophyll a content, antioxidant enzyme activities, reactive oxygen species (ROS) level, malondialdehyde (MDA) content and photosynthetic activity. The results revealed that ethyl cinnamate had acute inhibitory effects on the growth of Chlorella pyrenoidosa, and the inhibited degree tended to increase with increased concentrations. The effective concentration causing a 50% inhibition at 96 h was 5.45 mg c L(-1). Ethyl cinnamate induced the decrease of chlorophyll a, the over-accumulation of ROS and the increase of MDA. Therefore, it suggested that ethyl cinnamate could lead to the damage of cell membrane system and metabolic disorder through inducing lipid peroxidation via initiating ROS overproduction. And for scavenging ROS, the algae cells were protected from oxidative damages through increasing the activity of antioxidant enzymes. The results demonstrated ethyl cinnamate had acute inhibition to the maximum quantum yield and the potential activity of photosystem II of Chlorella pyrenoidosa, however, the photosynthetic activity could recover to some extent through self-regulation after some time. PMID:23487932

Gao, Li-Li; Guo, Pei-Yong; Su, Guang-Ming; Wei, Yan-Fang

2013-01-01

62

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

PubMed

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

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

2012-06-01

63

Biodiversity and physiological characteristics of Antarctic and Arctic lichens-associated bacteria.  

PubMed

The diversity and physiological characteristics of culturable bacteria associated with lichens from different habitats of the Arctic and Antarctica were investigated. The 68 retrieved isolates could be grouped on the basis of their 16S rRNA gene sequences into 26 phylotypes affiliated with the phyla Actinobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes and with the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Isolates belonging to the Alphaproteobacteria were the most abundant, followed by those belonging to Actinobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus. Phylogenetic analysis showed that approximately 21 % of the total isolates represented a potentially novel species or genus (?97 % sequence similarity). Strains belonging to the genera Sphingomonas, Frondihabitans, Hymenobacter, and Burkholderia were recovered from lichen samples from both geographic locations, implying common and important bacterial functions within lichens. Extracellular protease activities were detected in six isolates, affiliated with Burkholderia, Frondihabitans, Hymenobacter, Pseudomonas, and Rhodanobacter. Extracellular lipase activities were detected in 37 isolates of the genera Burkholderia, Deinococcus, Frondihabitans, Pseudomonas, Rhodanobacter, Sphingomonas, and Subtercola. This is the first report on the culturable bacterial diversity present within lichens from Arctic and Antarctica and the isolates described herein are valuable resources to decode the functional and ecological roles of bacteria within lichens. In addition, the low similarity (?97 %) of the recovered isolates to known species and their production of cold-active enzymes together suggest that lichens are noteworthy sources of novel bacterial strains for use in biotechnological applications. PMID:25001073

Lee, Yung Mi; Kim, Eun Hye; Lee, Hong Kum; Hong, Soon Gyu

2014-10-01

64

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

PubMed Central

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

Nikolaidis, Pantelis T.; Ingebrigtsen, J?rgen

2013-01-01

65

Physical and physiological characteristics of elite male handball players from teams with a different ranking.  

PubMed

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

Nikolaidis, Pantelis T; Ingebrigtsen, Jørgen

2013-01-01

66

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

Microsoft Academic Search

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 (?

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

67

Physiological response of Tamarix ramosissima under water stress along the lower reaches of Tarim River  

Microsoft Academic Search

Tamarix ramosissima is one of the constructive species growing on both sides of Tarim River which is favorable to constituting a natural barrier\\u000a containing local deserts and protecting the oasis. By analyzing characteristics of the main physiological indexes, such as\\u000a chlorophyll, soluble sugar, proline (Pro), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), indole-3-acetic\\u000a acid (IAA), C3-gibberellins (GA3) and abscisic acid

Li Zhuang; Yaning Chen

2006-01-01

68

Geographic distributions and physiological characteristics of co-existing Flaveria species in south-central Mexico  

Microsoft Academic Search

The genus Flaveria consists of 23 species with significant variation in photosynthetic physiologies. We tested whether photosynthetic pathway variation in seven co-existing Flaveria species corresponds to geographic distributions or physiological performance in C3, C4, and intermediate species growing under natural conditions in south-central Mexico. We found that Flaveria pringlei (C3) was the most widely distributed species with multiple growth habits.

Erika A. Sudderth; Francisco J. Espinosa-García; Noel M. Holbrook

2009-01-01

69

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

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

70

Physiological response of riparian plants to watering in hyper-arid areas of Tarim River, China  

Microsoft Academic Search

The physiological responses and adaptive strategies of Populus euphratica Oliv. (arbor species), Tamarix ramosissima Ldb. (bush species), and Apocynum venetum L. (herb species) to variations in water and salinity stress were studied in the hyper-arid environment of the Tarim River\\u000a in China. The groundwater table, the saline content of the groundwater, as well as the content of free proline, soluble

Xiao Ruan; Qiang Wang; Yaning Chen; Weihong Li

2007-01-01

71

Physiological responses of crops to sea water: Minimizing constraints that limit yield  

Microsoft Academic Search

\\u000a Growing plants under high salinity conditions using sea water or dilutions thereof impose many restrictions on growth and\\u000a development. These restrictions translate into low productivity and economical viability in the agricultural system. Since\\u000a most crop species are glycophytes, they are primarily suited to nonsaline conditions and the physiological adjustments and\\u000a morphological changes that are possible, are severely limited. The use

M. C. Shannon; F. N. Dalton; S. F. El-Sayed

72

Comparative reproductive and physiological responses of northern bobwhite and scaled quail to water deprivation  

USGS Publications Warehouse

We compared reproductive and physiological responses of captive female northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) under control and water deprivation conditions. Scaled quail required less food and water to reproduce successfully under control conditions than northern bobwhite. Additionally, in scaled quail, serum osmolality levels and kidney mass were unaffected by water deprivation, whereas in northern bobwhite, serum osmolality levels increased and kidney mass declined. This finding indicates that scaled quail may have osmoregulatory abilities superior to those of northern bobwhite. Under control conditions, northern bobwhite gained more body mass and produced more but smaller eggs than scaled quail. Under water deprivation conditions, northern bobwhite lost more body mass but had more laying bens with a higher rate of egg production than scaled quail. Our data suggest that northern bobwhite allocated more resources to reproduction than to body maintenance, while scaled quail apparently forego reproduction in favor of body maintenance during water deprivation conditions.

Giuliano, W.M.; Patino, R.; Lutz, R.S.

1998-01-01

73

Characteristics of a Novel Water Plasma Torch  

NASA Astrophysics Data System (ADS)

Relying on heat generated by plasma arc heating liquid water into steam as a swirl gas, a water plasma torch has the distinctive steam generation structure, which has various applications such as in the treatment of organic waste and hydrogen production for fuel cells in future vehicles. The operational features of the water plasma torch and water phase change process in the discharge chamber are investigated based on the temporal evolution of the voltage and current. The optical emission spectrum measurement shows that the water molecule in the plasma is decomposed into H, OH and O radicals. As the electrodes do not require water-cooling, the thermal efficiency of the torch is very high, which is confirmed by analytical calculation and experimental measurement.

Ni, Guo-Hua; Meng, Yue-Dong; Cheng, Cheng; Lan, Yan

2010-05-01

74

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

NASA Astrophysics Data System (ADS)

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.

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

75

Evidence That Severe Asthma Can Be Divided Pathologically into Two Inflammatory Subtypes with Distinct Physiologic and Clinical Characteristics  

Microsoft Academic Search

The mechanisms associated with the development of severe, corticosteroid (CS)-dependent asthma are poorly understood, but likely heterogenous. It was hypothesized that severe asthma could be di- vided pathologically into two inflammatory groups based on the presence or absence of eosinophils, and that the inflammatory subtype would be associated with distinct structural, physiologic, and clin- ical characteristics. Thirty-four severe, refractory CS-dependent

SALLY E. WENZEL; LAWRENCE B. SCHWARTZ; ESTHER L. LANGMACK; JANET L. HALLIDAY; JOHN B. TRUDEAU; ROBYN L. GIBBS; HONG WEI CHU

1999-01-01

76

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

E-print Network

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

Paris-Sud XI, Université de

77

Response of the physiological parameters of mango fruit (transpiration, water relations and antioxidant system) to its light and temperature environment.  

PubMed

Depending on the position of the fruit in the tree, mango fruit may be exposed to high temperature and intense light conditions that may lead to metabolic and physiological disorders and affect yield and quality. The present study aimed to determine how mango fruit adapted its functioning in terms of fruit water relations, epicarp characteristics and the antioxidant defence system in peel, to environmental conditions. The effect of contrasted temperature and light conditions was evaluated under natural solar radiation and temperature by comparing well-exposed and shaded fruit at three stages of fruit development. The sun-exposed and shaded peels of the two sides of the well-exposed fruit were also compared. Depending on fruit position within the canopy and on the side of a well-exposed fruit, the temperature gradient over a day affected fruit characteristics such as transpiration, as revealed by the water potential gradient as a function of the treatments, and led to a significant decrease in water conductance for well-exposed fruits compared to fruits within the canopy. Changes in cuticle thickness according to fruit position were consistent with those of fruit water conductance. Osmotic potential was also affected by climatic environment and harvest stage. Environmental conditions that induced water stress and greater light exposure, like on the sunny side of well-exposed fruit, increased the hydrogen peroxide, malondialdehyde and total and reduced ascorbate contents, as well as SOD, APX and MDHAR activities, regardless of the maturity stage. The lowest values were measured in the peel of the shaded fruit, that of the shaded side of well-exposed fruit being intermediate. Mango fruits exposed to water-stress-induced conditions during growth adapt their functioning by reducing their transpiration. Moreover, oxidative stress was limited as a consequence of the increase in antioxidant content and enzyme activities. This adaptive response of mango fruit to its climatic environment during growth could affect postharvest behaviour and quality. PMID:23267462

Léchaudel, Mathieu; Lopez-Lauri, Félicie; Vidal, Véronique; Sallanon, Huguette; Joas, Jacques

2013-04-15

78

Genome duplication and the evolution of physiological responses to water stress.  

PubMed

Whole-genome multiplication, or polyploidy, is common in angiosperms and many species consist of multiple cytotypes that have different physiological tolerances. However, the relative importance of genome duplication vs post-duplication evolutionary change in causing differentiation between cytotypes is not known. We examined the water relations of Chamerion angustifolium, a herbaceous perennial in which diploid and tetraploid cytotypes occupy different niches. To differentiate between the effects of genome duplication and evolutionary changes that followed polyploidization, we compared extant diploids and tetraploids with experimentally synthesized neotetraploids. Tetraploids had 32% higher xylem hydraulic conductivity (K(H)) than neotetraploids and 87% higher K(H) than diploids, but vulnerability to water stress induced cavitation and gas exchange sensitivity to water potential did not differ among cytotypes. Nevertheless, tetraploids took 22% and 30% longer to wilt than neotetraploids and diploids. A simple hydraulic model suggested that tetraploids deplete soil moisture to a greater degree than neotetraploids and diploids before reaching leaf water potentials that cause stomatal closure. We conclude that the different physiological tolerances and distribution of diploid and tetraploid C. angustifolium are unlikely to be caused solely by genome duplication. The enhanced ability of tetraploids to survive water stress likely evolved after polyploidization. PMID:19703115

Maherali, Hafiz; Walden, Alison E; Husband, Brian C

2009-11-01

79

Physiological relationships of the early posthatch performance of broilers to their embryo and eggshell characteristics.  

PubMed

Relationships between physiological parameters of early posthatch chicks with their corresponding egg and embryo parameters were examined in progeny of young broiler breeders. Four hundred and 80 broiler hatching eggs that were obtained from a 29-wk-old Ross 308 breeder flock were incubated on 8 replicate tray levels of an incubator until hatch. Between 10.5 and 18.5 d of incubation, internal (T(emb)) and external (T(ext)) egg temperatures were recorded twice daily using temperature transponders. Beginning at 18.5 d, the eggs were individually monitored for hatch every 12 h. Average T(emb), T(ext), and average daily incubational egg weight loss (EWL) for the 10.5- to 18.5-d incubation period were used to calculate eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to 100 g of set egg weight basis), and a G(H2O) constant (K(H2O)) for each egg. Chicks were grown out for 10 d in pens of a single battery brooder. In each pen, on d 3 posthatch, carcasses, yolk sac, liver, and pipping muscle samples were collected from at least 2 chicks that hatched from eggs implanted with transponders for determination of their relative weights and moisture concentrations. Livers and pipping muscles were also analyzed for glucose, glycogen, fat, and protein concentrations. Yolk sac weight as a percentage of chick BW (YW) and its moisture concentration (YSM) were positively correlated with T(emb). Egg g(H2O) was positively correlated with chick carcass moisture concentration and its relative weight as a percentage of set egg weight, but it was negatively correlated with YW. The positive functional relationship between T(emb) and incubation length may be mediated via their common positive relationships to YSM. A negative correlation was observed between percentage EWL and relative BW on d 0 and 0.5 posthatch for chicks hatched from unimplanted eggs. The results suggest that a higher g(H2O) results in an increased metabolism of the broiler embryo, which subsequently increases growth and yolk sac absorption in broiler chicks through 3 d posthatch. PMID:22700498

Pulikanti, R; Peebles, E D; Zhai, W; Bennett, L W; Gerard, P D

2012-07-01

80

[Bimodal physiological effect of picolinic acid derivatives is determined by the zwitterion structure characteristics].  

PubMed

In order to define the mechanism of action and causes for the manifestation of the bimodal physiological effect of certain picolinic acid derivatives we carried out quantum chemical calculations (QCC MO, 3-21G/6-31G* basis) of picolinic acid (1), 3,6-dichloropicolinic acid (2), acepox (3), and tetrapin (4) zwitterions. The exocyclic bond C(pyr)-Cexo is enhanced in zwitterions 3 and 4 with the bimodal physiological effect and loosened in zwitterions 1 and 2 without the effect. Zwitterions of the molecules 1-4 also differ in the pattern of the boundary molecular orbitals and electric charge distribution. On the basis of the obtained data, we propose that the difference in the physiological effect of compounds 1-4 is due to the different behavior of their zwitterions in aqueous solution. PMID:11357391

Konovalikhin, S V; Bo?kov, P Ia; Burlakova, E B

2001-01-01

81

Dynamic characteristics of gas-water interfacial plasma under water  

SciTech Connect

Gas-water interfacial plasmas under water were generated in a compact space in a tube with a sandglass-like structure, where two metal wires were employed as electrodes with an applied 35 kHz ac power source. The dynamic behaviors of voltage/current were investigated for the powered electrode with/without water cover to understand the effect of the gas-water interface. It is found that the discharge exhibits periodic pulsed currents after breakdown as the powered electrode is covered with water, whereas the electrical current reveals a damped oscillation with time with a frequency about 10{sup 6} Hz as the powered electrode is in a vapor bubble. By increasing water conductivity, a discharge current waveform transition from pulse to oscillation presents in the water covering case. These suggest that the gas-water interface has a significant influence on the discharge property.

Zheng, S. J.; Zhang, Y. C.; Ke, B.; Ding, F.; Tang, Z. L.; Yang, K.; Zhu, X. D. [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-06-15

82

Studies of the Fog-water Chemical Characteristics in China  

NASA Astrophysics Data System (ADS)

Research of chemical characteristics of fog-water developed rapidly in China since 1980. Observation, sampling and analysis have been done in cities , on the alps and beside the sea-sides. Studies about the acidity of cloud-fog water and the source of acid fog at each place have been done. The basic characteristics of fog water chemical composition also been detected. In many compositive fog observations , there explored the related factors of fog-water chemical characteristics as well as continuous fog-water collection, and studied the primary factors which affect the concentration of the fog water chemical composition. The paper presents the primary studies of fog-water chemical characteristics in China the last 30 years. Fog -water sampling and analysis have made marked progress. the cloud-fog water chemical composition and acidity were confirmed in many cities and mountain areas. Many efficacious works have been done about the source of chemical composition. The studies shown that the cloud-fog water in many of Chinese cities and mountain areas have been acidified. Fog-water in cities was polluted with high ion concentrations and jeopardize people’s health. It’s very urgent to control pollutant discharge, raise the vegetation plant cover rate, and improve ecological environment. The fog chemical research should be continue in-depth and development.

Liu, D. Y.; Li, Z. H.; Yang, F.; Bin, Z.; Yang, J.

2010-07-01

83

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

PubMed

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

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

2014-09-01

84

Flora 204 (2009) 8998 Geographic distributions and physiological characteristics of co-existing  

E-print Network

or physiological performance in C3, C4, and intermediate species growing under natural conditions in south photosynthesis; C3-C4-intermediate photosynthesis; C4 evolution; Chlorophyll fluorescence Introduction South ramosissima (C3-C4) were only located in the Tehuaca´ n Valley region while Flaveria trinervia (C4) was widely

Holbrook, N. Michele

85

A morpho-physiological approach differentiates bread wheat cultivars of contrasting tolerance under cyclic water stress.  

PubMed

Leaf micromorphological traits and some physiological parameters with potential relevance to drought tolerance mechanisms were investigated in four selected winter wheat varieties. Plants were subjected to two cycles of drought treatment at anthesis. Yield components confirmed contrasting drought-sensitive and -tolerant behavior of the genotypes. Drought tolerance was associated with small flag leaf surfaces and less frequent occurrence of stomata. Substantial variation of leaf cuticular thickness was found among the cultivars. Thin cuticle coincided with drought sensitivity and correlated with a high rate of dark-adapted water loss from leaves. Unlike in Arabidopsis, thickening of the cuticular matrix in response to water deprivation did not occur. Water stress induced epicuticular wax crystal depositions preferentially on the abaxial leaf surfaces. According to microscopy and electrolyte leakage measurements from leaf tissues, membrane integrity was lost earlier or to a higher extent in sensitive than in tolerant genotypes. Cellular damage and a decline of relative water content of leaves in sensitive cultivars became distinctive during the second cycle of water deprivation. Our results indicate strong variation of traits with potential contribution to the complex phenotype of drought tolerance in wheat genotypes. The maintained membrane integrity and relative water content values during repeated water limited periods were found to correlate with drought tolerance in the selection of cultivars investigated. PMID:25014261

Jäger, Katalin; Fábián, Attila; Eitel, Gabriella; Szabó, László; Deák, Csilla; Barnabás, Beáta; Papp, István

2014-09-01

86

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

E-print Network

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... stress in roses as well as physiological measurements of stomatal conductance, transpiration and total water potential. ln addition water stress regimens imposed on rootstock plants are assumed to have a direct effect on T-bud graft survival. CHAPTER...

Palacios Gilliland, Miguel Angel

2012-06-07

87

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

PubMed

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

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

2014-06-15

88

Spectral reflectance and radiance characteristics of water pollutants  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

89

Morphology and Physiology of Methanomonas Methanooxidans.  

National Technical Information Service (NTIS)

Pure cultures of methane-oxidizing bacteria isolated from soil, from the rumen of a fistulated cow, and from coalmine water were found to be identical in morphological, cultural, and physiological characteristics with Methanomanas methanooxidans of Brown ...

P. K. Stocks, C. S. McCleskey

1964-01-01

90

Characteristics of cooling water fouling in a heat exchange system  

Microsoft Academic Search

This study investigated the efficiency of the physical water treatment method in preventing and controlling fouling accumulation\\u000a on heat transfer surfaces in a laboratory heat exchange system with tap and artificial water. To investigate the fouling characteristics,\\u000a an experimental test facility with a plate type heat exchange system was newly built, where cooling and hot water moved in\\u000a opposite directions

Sun-Kyung Sung; Sang-Ho Suh; Dong-Woo Kim

2008-01-01

91

Short communication: Characteristics of student success in an undergraduate physiology and anatomy course.  

PubMed

Several factors affect the success of students in college classes. The objective of this research was to determine what factors affect success of undergraduate students in an anatomy and physiology class. Data were collected from 602 students enrolled in the Agriculture and Life Sciences (ALS) 2304 Animal Physiology and Anatomy course from 2005 through 2012. The data set included 476 females (79.1%) and 126 males (20.9%). Time to complete exams was recorded for each student. For statistical analyses, students' majors were animal and poultry sciences (APSC), agricultural sciences, biochemistry, biological sciences, dairy science, and "other," which combined all other majors. All analyses were completed using the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC). Gender, major, matriculation year, major by year interaction, gender by year interaction, and time to complete the exam affected final course grade. The significant gender effect was manifested in the final grade percentage of 75.9±0.4 for female students compared with 72.3±0.6 for male students. Junior males had final course grades comparable with those of females, but sophomore and senior males had lower final course grades than other combinations. Biology majors had a final grade of 82.4±0.6 and this grade was greater than all other majors. Students classified as "other" had a final score of 74.4±0.8, which was greater than agricultural science majors (69.5±0.9). The APSC grade (72.6±0.5) was higher than the agricultural science majors. Junior students had significantly greater final grades (76.1±0.5) than sophomores (73.3±0.6) and seniors (72.9±0.9). All biology students had greater final grades than all other majors, but biochemistry juniors had greater final course grades than APSC, agricultural science, and dairy science juniors. "Other" seniors had greater final course grades than agricultural science seniors. The regression for time to complete the exam was curvilinear and suggests that highest exam scores were at about 90-min completion time. It may be that some male students need better preparation for anatomy and physiology and their educational preparation should mimic that of female students more in terms of advance-placement biology in high school. These results suggest that biology majors might be better prepared for animal anatomy and physiology than other students. PMID:25087028

Gwazdauskas, F C; McGilliard, M L; Corl, B A

2014-10-01

92

Stable isotopes in plant physiology: using water isotopes to study water fluxes in a temperate forest  

NASA Astrophysics Data System (ADS)

Drought has profound consequences on vegetation, including decreases in instantaneous carbon uptake; damage that limits future uptake for the life of the plant; mortality that can lead to large sources of carbon to the atmosphere; and shifts in biogeography that alter future potential for carbon uptake and capacitance. These processes are largely absent from global models, for lack of understanding in how co-occurring plants compete for water, weak understanding of how plant hydraulics is coordinated to minimize risk of drought, and few empirical data to constrain superior models of these processes. Here we present the results of a large-scale field experiment at Silas Little Experimental Forest (NJ), where rainwater was diverted from a 10m^2 area around selected trees from two different species (either oak or pine trees) and either re-injected (control plots), discarded (drought plots) or replaced by isotopically labeled water (isotope plots). We sampled heavily the drought plots and collected valuable information on tree hydraulics under drought conditions, such as water potentials of soil, leaf and stem, photosynthetic rate or sap flow. At the isotope plots, we followed the injected water within the injection trees and the surrounding ones. In particular, using an innovative setup for in-situ measurement paired with a laser spectrometer, we studied the isotopes effects within the tree xylem, which gave us a better understanding of water uptake by the roots and its transport to the leaves. By tracking the labeled water in the surrounding trees, we were also able to quantify the importance of plant competition for water availability below ground. We show here the importance of understanding all the phases of the water transport in the biosphere to help constraining climate models.

Gerlein, C.; Wolf, A.; Caylor, K. K.

2013-12-01

93

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

94

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

SciTech Connect

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.

Pegg, W.J.

1984-01-01

95

The Effect of Active Learning on Student Characteristics in a Human Physiology Course for Nonmajors  

NSDL National Science Digital Library

This study investigated the effect of active-learning strategies on college studentsÃÂ achievement, motivation, and self-efficacy in a human physiology course for nonmajors. Variables were studied via a quasi-experimental, Solomon four-group design on 141 students at a small west-Texas university. Treatment groups were taught using a continuum-based, active-learning model implemented over the course of a semester. Control groups were taught using traditional didactic lecture methods. To assess the effects of the continuum-based active learning strategies, students were administered a comprehensive physiology content exam, the Motivated Strategies for Learning Questionnaire, and attitude surveys. Factorial analyses indicated that the treatment groups acquired significantly more content knowledge and were significantly more self-efficacious than students in the control groups. There were no significant differences in motivation. Attitude surveys indicated that students in both the treatment and control groups demonstrated a positive attitude toward active learning, believed it helped (or would help) them to learn the material, and would choose an active learning course in the future.

PhD R. Russell Wilke (Angelo State University Department of Biology)

2003-12-01

96

A Pig Model of the Preterm Neonate: Anthropometric and Physiological Characteristics  

PubMed Central

Background Large animal models are an essential tool in the development of rationally-based new clinical therapies for preterm infants. We provide a description of the newborn pig as a model of the preterm neonate in terms of growth parameters, physiology and the requirement for intensive care over a range of gestational ages. Methods Twenty-nine litters of piglets (n?=?298) were delivered by caesarean section at six timepoints during gestation from 91d to 113d (term?=?115d). Two groups, at 91 and 97d gestation, also received maternal glucocorticoid treatment. At four of these timepoints, piglets (n?=?79) were ventilated, sedated and monitored using standard neonatal intensive care techniques for up to 8 h in various experimental protocols. Results Body weight increased from mean 697 g (SD 193) at 91d gestation to 1331 g (SD 368) at 113d gestation. Piglets delivered at 97d gestation were able to be resuscitated and kept alive for at least 8 h on respiratory support after surfactant administration. Maternal glucocorticoid treatment 48 h and 24 h hours prior to delivery reduced the requirement for ventilator support and improved cardiovascular stability. Conclusion The pig provides a relevant model for the study of human preterm physiology and for investigation of novel therapies to improve outcomes. PMID:23874755

Eiby, Yvonne A.; Wright, Layne L.; Kalanjati, Viskasari P.; Miller, Stephanie M.; Bjorkman, Stella T.; Keates, Helen L.; Lumbers, Eugenie R.; Colditz, Paul B.; Lingwood, Barbara E.

2013-01-01

97

Morpho-physiologic characteristics of dorsal subicular network in mice after pilocarpine-induced status epilepticus.  

PubMed

The goal of this study was to examine the morpho-physiologic changes in the dorsal subiculum network in the mouse model of temporal lobe epilepsy using extracellular recording, juxtacellular and immunofluorescence double labeling, and anterograde tracing methods. A significant loss of total dorsal subicular neurons, particularly calbindin, parvalbumin (PV) and immunopositive interneurons, was found at 2 months after pilocarpine-induced status epilepticus (SE). However, the sprouting of axons from lateral entorhinal cortex (LEnt) was observed to contact with surviving subicular neurons. These neurons had two predominant discharge patterns: bursting and fast irregular discharges. The bursting neurons were mainly pyramidal cells, and their dendritic spine density and bursting discharge rates were increased significantly in SE mice compared with the control group. Fast irregular discharge neurons were PV-immunopositive interneurons and had less dendritic spines in SE mice when compared with the control mice. When LEnt was stimulated, bursting and fast irregular discharge neurons had much shorter latency and stronger excitatory response in SE mice compared with the control group. Our results illustrate that morpho-physiologic changes in the dorsal subiculum could be part of a multilevel pathologic network that occurs simultaneously in many brain areas to contribute to the generation of epileptiform activity. PMID:19298597

He, De Fu; Ma, Dong Liang; Tang, Yong Cheng; Engel, Jerome; Bragin, Anatol; Tang, Feng Ru

2010-01-01

98

14 CFR 25.239 - Spray characteristics, control, and stability on water.  

...characteristics, control, and stability on water. 25.239 Section 25.239 Aeronautics...CATEGORY AIRPLANES Flight Ground and Water Handling Characteristics § 25.239...characteristics, control, and stability on water. (a) For seaplanes and...

2014-01-01

99

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

Microsoft Academic Search

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

Snehlata Bhandari; Mamta Sajwan; N. S. Bisht

100

Performance Characteristics of a New Generation Pressure Microsensor for Physiologic Applications  

PubMed Central

A next generation fiber-optic microsensor based on the extrinsic Fabry–Perot interferometric (EFPI) technique has been developed for pressure measurements. The basic physics governing the operation of these sensors makes them relatively tolerant or immune to the effects of high-temperature, high-EMI, and highly-corrosive environments. This pressure microsensor represents a significant improvement in size and performance over previous generation sensors. To achieve the desired overall size and sensitivity, numerical modeling of diaphragm deflection was incorporated in the design, with the desired dimensions and calculated material properties. With an outer diameter of approximately 250 µm, a dynamic operating range of over 250 mmHg, and a sampling frequency of 960 Hz, this sensor is ideal for the minimally invasive measurement of physiologic pressures and incorporation in catheter-based instrumentation. Nine individual sensors were calibrated and characterized by comparing the output to a U.S. National Institute of Standards and Technology (NIST) Traceable reference pressure over the range of 0–250 mmHg. The microsensor performance demonstrated accuracy of better than 2% full-scale output, and repeatability, and hysteresis of better than 1% full-scale output. Additionally, fatigue effects on five additional sensors were 0.25% full-scale output after over 10,000 pressure cycles. PMID:19495983

Cottler, Patrick S.; Karpen, Whitney R.; Morrow, Duane A.; Kaufman, Kenton R.

2009-01-01

101

Performance characteristics of a new generation pressure microsensor for physiologic applications.  

PubMed

A next generation fiber-optic microsensor based on the extrinsic Fabry-Perot interferometric (EFPI) technique has been developed for pressure measurements. The basic physics governing the operation of these sensors makes them relatively tolerant or immune to the effects of high-temperature, high-EMI, and highly-corrosive environments. This pressure microsensor represents a significant improvement in size and performance over previous generation sensors. To achieve the desired overall size and sensitivity, numerical modeling of diaphragm deflection was incorporated in the design, with the desired dimensions and calculated material properties. With an outer diameter of approximately 250 microm, a dynamic operating range of over 250 mmHg, and a sampling frequency of 960 Hz, this sensor is ideal for the minimally invasive measurement of physiologic pressures and incorporation in catheter-based instrumentation. Nine individual sensors were calibrated and characterized by comparing the output to a U.S. National Institute of Standards and Technology (NIST) Traceable reference pressure over the range of 0-250 mmHg. The microsensor performance demonstrated accuracy of better than 2% full-scale output, and repeatability, and hysteresis of better than 1% full-scale output. Additionally, fatigue effects on five additional sensors were 0.25% full-scale output after over 10,000 pressure cycles. PMID:19495983

Cottler, Patrick S; Karpen, Whitney R; Morrow, Duane A; Kaufman, Kenton R

2009-08-01

102

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

NASA Technical Reports Server (NTRS)

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.

Greenleaf, John E.

1984-01-01

103

Effect of water compressibility on nonstationary characteristics of hydraulic turbines  

NASA Astrophysics Data System (ADS)

We have investigated the effect of water compressibility on the nonstationary characteristics of turbines connected with the ability of the liquid to execute natural hydroacoustic vibrations in the setting of hydroelectric units. We have constructed a model of the setting up of forced hydroacoustic vibrations in the water conduit due to the precession of the vortex core running off the turbine. The conditions for the possibility that low-frequency hydroacoustic natural vibrations will arise have been considered.

Kurzin, V. B.

2013-09-01

104

Dynamics of phytoplankton pigment characteristics in the Biya head water  

Microsoft Academic Search

Concentrations of phytoplankton photosynthetic pigments were measured at the Biya head water (in the immediate vicinity of\\u000a Lake Teletskoe) every 10 days from July 1998 through December 2001. Comparison of phytoplankton pigment characteristics at\\u000a the river’s head waters and at the surface of the lake’s pelagic zone for the ice-free period shows that the monitoring data\\u000a give a clear picture

T. V. Kirillova; V. V. Kirillov; N. A. Gaevskii

2009-01-01

105

Water films and scaling of soil characteristic curves at low water contents  

Microsoft Academic Search

Individual contributions of capillarity and adsorptive surface forces to the matric potential are seldom differentiated in determination of soil water characteristic (SWC) curves. Typically, capillary forces dominate at the wet end, whereas adsorptive surface forces dominate at the dry end of a SWC where water is held as thin liquid films. The amount of adsorbed soil water is intimately linked

Markus Tuller

2005-01-01

106

Effects of de-icing salt on ground water characteristics.  

PubMed

The effect of "road salt" on the characteristics of Massachusetts drinking water supplies has been significant and cumulative rather than transient or seasonal. De-icing salt is essentially all sodium chloride. Calcium chloride accounted for only three percent of the total salt used. However, hardness content, as well as sodium ion concentration, has increased greatly in ground waters in the past decade. The changing composition of our water supplies has agricultural, economic, and public health implications. This study attempts to quantify the stoichiometry of these changes in concentration, which are in part due to an ion-exchange mechanism in the soil. PMID:238830

O'Brien, J E; Majewski, J C

1975-01-01

107

Stratospheric water inferred from Lagrangian Cold Point characteristics  

NASA Astrophysics Data System (ADS)

Total water was recently measured onboard the Geophysica high-altitude aircraft using the Jülich fluorescence hygrometer FISH during the three tropical campaigns TroCCiNOx (January-February 2005), SCOUT-O3 (November-December 2005) and AMMA (August 2006) over Southern Brazil, Northern Australia and West Africa. Trajectories are initialized at the flight locations, calculated backwards for ten days and the Lagrangian Cold Point (LCP) characteristics determined along the paths. To test whether stratospheric water values can be deduced from the temperature history of air, minimum saturation water vapor is derived from the LCP-temperature and compared to the measurements.

Ploeger, F.; Konopka, P.; Schiller, C.

2009-04-01

108

Aerodynamic Characteristics of Water Rocket and Stabilization of Flight Trajectory  

NASA Astrophysics Data System (ADS)

The aerodynamic characteristics of water rockets are analyzed experimentally by wind tunnel testing. Aerodynamic devices such as vortex generators and dimples are tested and their effectiveness to the flight performance of water rocket is discussed. Attaching vortex generators suppresses the unsteady body fluttering. Dimpling the nose reduces the drag coefficient in high angles of attack. Robust design approach is applied to water rocket design for flight stability and optimum water rocket configuration is determined. Semi-sphere nose is found to be effective for flight stability and it is desirable for the safety of landing point. Stiffed fin attachment is required for fins to work properly as aerodynamic device and it enhances the flight stability of water rockets.

Watanabe, Rikio; Tomita, Nobuyuki; Takemae, Toshiaki

109

Relationships between heart rate and physiological parameters of performance in top-level water polo players.  

PubMed

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 ([Formula: see text]O2max, Th1vent, Th2vent). Each athlete performed a [Formula: see text]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 [Formula: see text]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 [Formula: see text]O2max and that HR monitoring could be of great interest in the control of water polo training sessions. PMID:24917687

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

2014-03-01

110

Liquid state DNP for water accessibility measurements on spin-labeled membrane proteins at physiological temperatures  

NASA Astrophysics Data System (ADS)

We demonstrate the application of continuous wave dynamic nuclear polarization (DNP) at 0.35 T for site-specific water accessibility studies on spin-labeled membrane proteins at concentrations in the 10-100 ?M range. The DNP effects at such low concentrations are weak and the experimentally achievable dynamic nuclear polarizations can be below the equilibrium polarization. This sensitivity problem is solved with an optimized home-built DNP probe head consisting of a dielectric microwave resonator and a saddle coil as close as possible to the sample. The performance of the probe head is demonstrated with both a modified pulsed EPR spectrometer and a dedicated CW EPR spectrometer equipped with a commercial NMR console. In comparison to a commercial pulsed ENDOR resonator, the home-built resonator has an FID detection sensitivity improvement of 2.15 and an electron spin excitation field improvement of 1.2. The reproducibility of the DNP results is tested on the water soluble maltose binding protein MalE of the ABC maltose importer, where we determine a net standard deviation of 9% in the primary DNP data in the concentration range between 10 and 100 ?M. DNP parameters are measured in a spin-labeled membrane protein, namely the vitamin B12 importer BtuCD in both detergent-solubilized and reconstituted states. The data obtained in different nucleotide states in the presence and absence of binding protein BtuF reveal the applicability of this technique to qualitatively extract water accessibility changes between different conformations by the ratio of primary DNP parameters ?. The ?-ratio unveils the physiologically relevant transmembrane communication in the transporter in terms of changes in water accessibility at the cytoplasmic gate of the protein induced by both BtuF binding at the periplasmic region of the transporter and ATP binding at the cytoplasmic nucleotide binding domains.

Doll, Andrin; Bordignon, Enrica; Joseph, Benesh; Tschaggelar, René; Jeschke, Gunnar

2012-09-01

111

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

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

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

2007-01-01

112

Physiological indicators of stress and meat and carcass characteristics in tail bitten slaughter pigs  

PubMed Central

Background Tail biting is a common welfare problem in pig production and in addition to being a sign of underlying welfare problems, tail biting reduces welfare in itself. The aim of this study was to evaluate the effects of tail biting on different pre and post mortem indicators of stress in slaughter pigs and on carcass and meat characteristics. A total of 12 tail bitten (TB) and 13 control (C) pigs from a farm with a long-term tail biting problem were selected for salivary cortisol analyses before and after transport to the slaughterhouse. After stunning, samples were taken for the analysis of serum cortisol, blood lactate, intestinal heat shock protein 70 (HSP70), and meat quality characteristics. In addition, body temperature immediately after and muscle temperature 35 min after stunning were measured, as well as lean meat percentage and carcass weight. Results TB pigs showed a lower cortisol response to the transport-induced stress than C pigs and also had a lower serum cortisol concentration after stunning. HSP70 content in the small intestine was higher in the TB pigs than in C pigs. TB pigs had a considerably lower carcass weight therefore produced a lower total amount of lean meat per carcass than C pigs. Conclusions This study suggests that prolonged or repeated stress in the form of tail biting causes a blunted stress response, possibly a sign of hypocortisolism. In addition, it underlines the importance of reducing tail biting, both from an animal welfare and an economic point-of-view. PMID:24172255

2013-01-01

113

Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion.  

PubMed

The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI. PMID:23950166

Florian, John P; Simmons, Erin E; Chon, Ki H; Faes, Luca; Shykoff, Barbara E

2013-11-01

114

Development of Physiologically Based Toxicokinetic Models for Improving the Human Indoor Exposure Assessment to Water Contaminants: Trichloroethylene and Trihalomethanes  

Microsoft Academic Search

Generally, ingestion is the only route of exposure that is considered in the risk assessment of drinking water contaminants. However, it is well known that a number of these contaminants are volatile and lipophilic and therefore highly susceptible to being absorbed through other routes, mainly inhalation and dermal. The objective of this study was to develop physiologically based human toxicokinetic

Sami Haddad; Ginette-Charest Tardif; Robert Tardif

2006-01-01

115

The effects of irrigation regimes on the water use, dry matter production and physiological responses of paddy rice  

Microsoft Academic Search

In most cases, rice production is associated with flooding irrigation and the efficiency of irrigated water use (WUEi) is\\u000a generally lower for production of rice than for other crops. We have examined the effects of various irrigation regimes on\\u000a water consumption in a well-puddled paddy field, as well as on dry matter production, grain yield and physiological responses\\u000a of the

Jun Lu; Taiichiro Ookawa; Tadashi Hirasawa

2000-01-01

116

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

Microsoft Academic Search

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,

Richard Colin Playle

1989-01-01

117

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

Microsoft Academic Search

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,

Richard Colin Playle

1990-01-01

118

Water and wastewater industries: Characteristics and DSM opportunities  

SciTech Connect

The use of electricity for water and wastewater treatment is increasing due to demands for increased service and new regulations for upgraded treatment. Options available to control the electricity costs may consist of technological changes, improved management, and participation in electric utility sponsored demand-side management (DSM) programs. Appropriate options for a specific system will vary depending on the system characteristics, availability of electric utility programs to assist the water and wastewater utilities, and adequate funding and management skills to implement changes. This report provides electricutility planning, marketing, and customer service staff with a practical tool to better understand the water and wastewater industries and the challenges they face. The report may also be used by water and wastewater utilities to determine how DSM might be applied to their particular system. Descriptions of technologies used in water and wastewater treatment are provided together with companion electricity use characteristics. Examples and discussions of DSM opportunities are also provided. The report concludes with guidance and summary data for developing and evaluating DSM plans to realize such opportunities.

Burton, F.L. (Burton Environmental Engineering, Los Altos, CA (United States)); Stern, F. (RCG/Hagler, Bailly, Inc., Boulder, CO (United States))

1993-03-01

119

Physiological characteristics of gastric contractions and circadian gastric motility in the free-moving conscious house musk shrew (Suncus murinus).  

PubMed

Although many studies have demonstrated the physiological action of motilin on the migrating motor complex, the precise mechanisms remain obscure. To obtain new insights into the mechanisms, we focused on the house musk shrew (Suncus murinus, suncus used as a laboratory name) as a small model animal for in vivo motilin study, and we studied the physiological characteristics of suncus gastrointestinal motility. Strain gauge transducers were implanted on the serosa of the gastric body and duodenum, and we recorded gastrointestinal contractions in the free-moving conscious suncus and also examined the effects of intravenous infusion of various agents on gastrointestinal motility. During the fasted state, the suncus stomach and duodenum showed clear migrating phase III contractions (intervals of 80-150 min) as found in humans and dogs. Motilin (bolus injection, 100-300 ng/kg; continuous infusion, 10-100 ng·kg(-1)·min(-1)) and erythromycin (80 ?g·kg(-1)·min(-1)) induced gastric phase III contractions, and motilin injection also increased the gastric motility index in a dose-dependent manner (P < 0.05, vs. saline). Pretreatment with atropine completely abolished the motilin-induced gastric phase III contractions. On the other hand, in the free-feeding condition, the suncus showed a relatively long fasting period in the light phase followed by spontaneous gastric phase III contractions. The results suggest that the suncus has almost the same gastrointestinal motility and motilin response as those found in humans and dogs, and we propose the suncus as a new small model animal for studying gastrointestinal motility and motilin in vivo. PMID:20686171

Sakahara, Satoshi; Xie, Zuoyun; Koike, Kanako; Hoshino, Satoya; Sakata, Ichiro; Oda, Sen-ichi; Takahashi, Toku; Sakai, Takafumi

2010-10-01

120

Physical and Water Absorption Characteristics of Some Improved Rice Varieties  

Microsoft Academic Search

The physical and water absorption characteristics of paddy and brown rice from some early maturing Oryza sativa varieties and newly developed interspecific (O. sativa × Oryza glaberrima) rice varieties were studied. The physical dimensions (length, breadth and width, length\\/width ratio, equivalent diameter),\\u000a grain surface area and volume, sphericity, 1,000-kernel weight, bulk and true densities as well as porosity were determined.

Taofik Akinyemi Shittu; M. B. Olaniyi; A. A. Oyekanmi; K. A. Okeleye

121

Water sorption characteristics of resin-modified glass-ionomer cements  

Microsoft Academic Search

When restorative materials take up water, their dimensions and structural integrity may be affected. This study determined, using gravimetric measurements, the water sorption characteristics of four resin-modified glass-ionomer cements (RMGICs) immersed in either distilled water or artificial saliva. The dimensional changes on water storage were also determined. The RMGICs exhibited differing characteristics as they absorbed water. Percentage water uptake and

Widchaya Kanchanavasita; H. M. Anstice; Gavin J. Pearson

1997-01-01

122

Physiological Maturity in Wheat Based on Kernel Water and Dry Matter  

Microsoft Academic Search

desiccants or windrowing) without reducing wheat yield, thereby providing better returns in double-crop systems. Estimation of the time of physiological maturity could be beneficial The most precise method of determining the time of to avoid yield penalties due to lodging, sprouting, hail, and other harvest risks. The aim of our study was to evaluate a simple empirical physiological maturity in

Daniel F. Calderini; Leonor G. Abeledo; Gustavo A. Slafer

2000-01-01

123

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution.  

PubMed

Elephant movement patterns in relation to surface water demonstrate that they are a water-dependent species. Thus, there has been interest in using surface water management to mitigate problems associated with localized elephant overabundance. However, the physiological mechanisms underlying the elephant's water dependence remain unclear. Although thermoregulation is likely an important driver, the relationship between thermoregulation, water use and climate has not been quantified. We measured skin surface temperature of and cutaneous water loss from 13 elephants (seven African, 3768±642 kg; six Asian, 3834±498 kg) and determined the contribution of evaporative cooling to their thermal and water budgets across a range of air temperatures (8-33°C). We also measured respiratory evaporative water loss and resting metabolic heat production on a subset of elephants (N=7). The rate of cutaneous evaporative water loss ranged between 0.31 and 8.9 g min(-1) m(-2) for Asian elephants and 0.26 and 6.5 g min(-1) m(-2) for African elephants. Simulated thermal and water budgets using climate data from Port Elizabeth, South Africa, and Okaukuejo, Namibia, suggested that the 24-h evaporative cooling water debt incurred in warm climates can be more than 4.5 times that incurred in mesic climates. This study confirms elephants are obligate evaporative coolers but suggests that classification of elephants as water dependent is insufficient given the importance of climate in determining the magnitude of this dependence. These data highlight the potential for a physiological modeling approach to predicting the utility of surface water management for specific populations. PMID:23842629

Dunkin, Robin C; Wilson, Dinah; Way, Nicolas; Johnson, Kari; Williams, Terrie M

2013-08-01

124

Study of the physiological characteristics of the medicinal mushroom Trametes pubescens (higher Basidiomycetes) during the laccase-producing process.  

PubMed

The study of the physiological characteristics of the medicinal mushroom Trametes pubescens was conducted under submerged cultures, suggesting that the laccase activity was positively correlated with oxidative level and culture conditions. Mycelial biomass and laccase activity in medium I were higher than those in medium II, which indicated that laccase activity was correlated with mycelium growth. The enhancement in mycelial biomass presented the logarithmic increase at days 6-8 and the peak value on the day 12 after inoculation. During liquid cultivation, increases in the amounts of malondialdehyde, hydrogen peroxide, and ascorbic acid were observed. In addition, the higher activities of superoxide dismutase and total antioxidative capacity still could be detected during this period. However, better ability to restrain hydroxyl free radical and catalase had a negative influence on laccase activity. It was evident that the fungal strain T. pubescens was under oxidative stress during the laccase-producing process. When the concentrations of H2O2 and Fe2+ were 3 and 30 mmol/L, respectively, the laccase activity reached to its peak at 37.21 U/L after a 14-day incubation period. It was concluded that a relationship between laccase synthesis and antioxidative capability existed in fungal cells, which could be regulated by reactive oxygen. PMID:23557372

Si, Jing; Cui, Bao-Kai

2013-01-01

125

Physiological characteristics of postinhibitory rebound depolarization in neurons of the rat's dorsal cortex of the inferior colliculus studied in vitro.  

PubMed

The inferior colliculus (IC) is a major center for neural integration in the auditory pathway. The IC processes inputs from the lower brainstem as well as from higher centers in the auditory system. To understand cellular mechanisms of IC neurons in auditory processing, we investigated physiological characteristics of the rebound depolarization (RD) following membrane hyperpolarization in neurons of the rat's dorsal cortex of the inferior colliculus (ICD). Whole-cell patch clamp recordings were made from ICD neurons in brain slices. In more than half of the ICD neurons, there was a RD accompanied by one or two anode break action potentials (APs) following membrane hyperpolarization. The RD was Ca(2+) mediated and primarily due to activation of low-threshold T-type Ca(2+) channels. Generation of the RD and anode break APs depended on the magnitude and duration of the preceding hyperpolarization. Larger and longer hyperpolarization induced a larger, shorter and faster rebound, and therefore earlier anode break APs. However, with further hyperpolarization the RD became constant in amplitude and duration despite increases in the strength or duration of the preceding hyperpolarization. Usually, membrane hyperpolarization as small as -15 mV for 100-200 ms was enough to induce a pronounced rebound of 15-20 mV. The RD in IC neurons may provide a neuronal mechanism for integrating excitatory inputs arriving soon after a period of synaptic inhibition and therefore processing specific aspects of auditory information. PMID:18586018

Sun, Hongyu; Wu, Shu Hui

2008-08-21

126

Soil and water characteristics of a young surface mine wetland  

NASA Astrophysics Data System (ADS)

Coal companies are reluctant to include wetland development in reclamation plans partly due to a lack of information on the resulting characteristics of such sites. It is easier for coal companies to recreate terrestrial habitats than to attempt experimental methods and possibly face significant regulatory disapproval. Therefore, we studied a young (10 years) wetland on a reclaimed surface coal mine in southern Illinois so as to ascertain soil and water characteristics such that the site might serve as a model for wetland development on surface mines. Water pH was not measured because of equipment problems, but evidence (plant life, fish, herpetofauna) suggests suitable pH levels. Other water parameters (conductivity, salinity, alkalinity, chloride, copper, total hardness, iron, manganese, nitrate, nitrite, phosphate, and sulfate) were measured, and only copper was seen in potentially high concentrations (but with no obvious toxic effects). Soil variables measured included pH, nitrate, nitrite, ammonia, potassium, calcium, magnesium, manganese, aluminum, iron, sulfate, chloride, and percent organic matter. Soils were slightly alkaline and most parameters fell within levels reported for other studies on both natural and manmade wetlands. Aluminum was high, but this might be indicative more of large amounts complexed with soils and therefore unavailable, than amounts actually accessible to plants. Organic matter was moderate, somewhat surprising given the age of the system.

Andrew Cole, C.; Lefebvre, Eugene A.

1991-05-01

127

Effects of hot tea, coffee and water ingestion on physiological responses and mood: the role of caffeine, water and beverage type  

Microsoft Academic Search

Psychopharmacological studies using caffeinated beverages or caffeine have rarely considered temporal effects on psychological\\u000a and physiological function or the specific contribution of caffeine, hot water, or beverage type to the observed effects.\\u000a The effect of 400?ml hot tea, coffee, and water consumption on systolic and diastolic blood pressure (SBP and DBP), heart\\u000a rate, skin conductance (a measure of sympathetic nervous

P. Quinlan; Laurence Aspinall

1997-01-01

128

Effects of transportation at high ambient temperatures on physiological responses, carcass and meat quality characteristics of three breeds of Omani goats.  

PubMed

The experiment was designed to determine the effects of short road transportation in an open truck during the hot season on live weight shrink, physiological responses, carcass, and meat quality characteristics in three breeds of Omani goats. Forty-two male goats (12months of age) representing equally three breeds of Omani goats (Batina, Dhofari, and Jabal Akhdar) were divided into two groups: 2h transportation stress (TS) or not transported (NT). The NT group remained unstressed in holding pens with feed and water provided ad libitum prior to slaughter, while the TS group was transported on the day of slaughter 100km in an open truck. The average temperature during transportation was 37°C. All animals were blood-sampled before loading and prior to slaughter via jugular venipuncture. Animals were weighed just before loading onto a truck and after transport to assess shrinkage. Muscle shear force, sarcomere length, pH, expressed juice, color, and cooking loss were measured on samples from Mm longissimus dorsi (LD), biceps femoris (BF), and semitendinosus (ST) muscles collected at 24h postmortem at 1-3°C. Live weight shrinkage losses were between 1.07 and 1.28kg. The TS goats had higher plasma cortisol (P<0.01), adrenaline, nor-adrenaline, and dopamine concentrations (P<0.05) than NS goats. Blood serum from Batina goats had significantly (P<0.05) higher cortisol, adrenaline and dopamine and nor-adrenaline concentrations than those from Jabal Akdhar goats. Transportation stress had a significant (P<0.05) effect on meat quality characteristics of the LD, BF, and ST muscles. Meat from TS goats had significantly higher ultimate pH, expressed juice, cooking loss percentage, shear force, but significantly lower sarcomere length, L(?), a(?), and b(?) values. LD muscles of Batina goats had significantly higher ultimate pH values and lower L(?) values than Dhofari and Jabal Akdhar goats. These results indicated that subjecting goats to the 2-hour road transportation with high ambient temperatures can generate major physiological and muscle metabolism responses. PMID:22062562

Kadim, I T; Mahgoub, O; Al-Kindi, A; Al-Marzooqi, W; Al-Saqri, N M

2006-08-01

129

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

E-print Network

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

Palen, Wendy J.

130

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

E-print Network

decreased all measured growth and physiological parameters for all rootstocks implying that this scion-rootstock combination may not be ideal. In the second experiment, TAMU mini watermelons were grafted to four rootstocks to determine if any of these would...

Simpson, Catherine Ross

2013-12-02

131

Measurement of "turbidity" and related characteristics of natural waters  

USGS Publications Warehouse

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)

Pickering, R.J.

1976-01-01

132

Relationship between landscape characteristics and surface water quality.  

PubMed

The effects of landscape characteristics on surface water quality were evaluated in terms of land-use condition, soil type and slope. The case area, the Chichiawan stream in the Wulin catchment in Taiwan, is Formosan landlocked salmon's natural habitat. Due to the agriculture behavior and mankind's activities, the water and environmental quality has gradually worsened. This study applied WinVAST model to predict hydrological responses and non-point source pollution (NPSP) exports in the Wulin catchment. The land-use condition and the slope of land surface in a catchment are major effect factors for watershed responses, including flows and pollutant exports. This work discussed the possible variation of watershed responses induced by the change of land-use condition, soil type and slope, etc. The results show that hydrological responses are highly relative to the value of Curve Number (CN); Pollutant exports have large relation to the average slope of the land surface in the Wulin catchment. PMID:18185979

Chang, C L; Kuan, W H; Lui, P S; Hu, C Y

2008-12-01

133

Eco-physiological response of Populus euphratica Oliv. to water release of the lower reaches of the Tarim River, China  

Microsoft Academic Search

Eco-physiological and plant performance responses and acclimation of Populus euphratica Oliv. to water release of the lower reaches of Tarim River, China were investigated. Three representative areas and 15 transects\\u000a were selected along the lower reaches of the Tarim River. The groundwater level and salt content as well as plant performance\\u000a and the contents of proline, soluble sugar, and plant

Q. Wang; X. Ruan; Y. N. Chen; W. H. Li

2007-01-01

134

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

NASA Astrophysics Data System (ADS)

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.

Gharun, Mana; Turnbull, Tarryn; Adams, Mark

2014-05-01

135

Characteristic mega-basin water storage behavior using GRACE  

PubMed Central

[1]?A long-standing challenge for hydrologists has been a lack of observational data on global-scale basin hydrological behavior. With observations from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission, hydrologists are now able to study terrestrial water storage for large river basins (>200,000 km2), with monthly time resolution. Here we provide results of a time series model of basin-averaged GRACE terrestrial water storage anomaly and Global Precipitation Climatology Project precipitation for the world’s largest basins. We address the short (10 year) length of the GRACE record by adopting a parametric spectral method to calculate frequency-domain transfer functions of storage response to precipitation forcing and then generalize these transfer functions based on large-scale basin characteristics, such as percent forest cover and basin temperature. Among the parameters tested, results show that temperature, soil water-holding capacity, and percent forest cover are important controls on relative storage variability, while basin area and mean terrain slope are less important. The derived empirical relationships were accurate (0.54???Ef???0.84) in modeling global-scale water storage anomaly time series for the study basins using only precipitation, average basin temperature, and two land-surface variables, offering the potential for synthesis of basin storage time series beyond the GRACE observational period. Such an approach could be applied toward gap filling between current and future GRACE missions and for predicting basin storage given predictions of future precipitation. PMID:24563556

Reager, J T; Famiglietti, James S

2013-01-01

136

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

137

[Effects of exogenous nitric oxide on physiological characteristics of longan (Dimocarpus longana) seedlings under acid rain stress].  

PubMed

This paper studied the effects of exogenous nitric oxide donor sodium nitroprusside (SNP) on the chlorophyll content, antioxidant enzyme activities, and osmotic regulation substances of longan (Dimocarpus longana 'Fuyan') seedlings under acid rain (pH 3.0) stress. Under the acid rain stress, the seedling leaf superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and chlorophyll, soluble protein and soluble sugar contents decreased obviously, while the leaf malondialdedyde content had a remarkable increase, suggesting the toxic effect of the acid rain on the seedlings. Exogenous nitric oxide had dual nature on the physiological characteristics of longan seedlings under acid rain stress. Applying 0.1-0.5 mmol x L(-1) of SNP improved the SOD, POD and CAT activities and the chlorophyll, soluble protein and soluble sugar contents significantly, and decreased the malondialdedyde content. Low concentrations SNP reduced the oxidative damage caused by the acid rain stress, and 0.5 mmol x L(-1) of SNP had the best effect. Under the application of 0.5 mmol x L(-1) of SNP, the total chlorophyll, soluble protein, and soluble sugar contents and the SOD, POD and CAT activities increased by 76.0%, 107.0%, 216.1%, 150. 0%, 350.9% and 97.1%, respectively, and the malondialdedyde content decreased by 46.4%. It was suggested that low concentration (0.1-0.5 mmol x L(-1)) SNP could alleviate the toxic effect of acid rain stress on longan seedlings via activating the leaf antioxidant enzyme activities and reducing oxidative stress, while high concentration SNP (1.0 mmol x L(-1)) lowered the mitigation effect. PMID:24380343

Liu, Jian-fu; Wang, Ming-yuan; Yang, Chen; Zhu, Ai-jun

2013-08-01

138

Definition and characteristics of the water abundant season in Korea  

NASA Astrophysics Data System (ADS)

In contrast to the normal seasons that are classified by the distribution of temperature and precipitation, this study defines a new concept of the water abundant season (WAS) when water is more abundant than in other seasons. We investigated its characteristics on 60 stations in Korea, and compared it with Changma (the rainy season). In this study, Available Water Resources Index (AWRI), which is a summed daily precipitation accumulated for more than 365 days with a time-dependent reduction function and reflects the current water condition, was used to quantify the water amount. In addition, the median value of 30 year's daily AWRI was used as the criterion value dividing WAS from other seasons. The results show that the terminologies on water resources have changed from qualitative concepts such as abundance, deficit, and continuous rainfall, to quantitative values using AWRI. In detail, it was known that the WAS in Korea starts on 2 July and ends on 25 December, lasting for 176 days. The onset date of WAS in Korea is getting earlier, with a trend of 2.9 days/decade. The end date does later with a delay of 7.5 days/decade, and the duration is increasing at 10.4 days/decade. We looked at the WAS by stations and saw, on average, that 14 June was the earliest onset date in Seogwipo and 29 July was the latest one in Sokcho, representing a difference of 45 days. The earliest end date was in Tongyeong at 5 December and the latest one is in Uljin at 16 January of the following year, a difference of 41 days. Tongyeong had the shortest (166 days) WAS duration and Uljin had the longest (207 days) on average. The big spatial differences of the criterion values per station were detected and quantified. The largest criterion value for WAS were recorded in Seongsan with 270.7 mm, which is almost double of the smallest value, which was recorded in Uiseong (135.9 mm). Comparing WAS with the Changma (the rainy season in Korea) showed that the onset date of WAS is close to that of Changma, but the end date shows a big difference. It is also known that WAS was more useful than Changma in detecting and demonstrating both of the season's progress and the seasonal state of water climates.

Park, So-Ra; Oh, Su-Bin; Byun, Hi-Ryong

2014-05-01

139

Water Jet Impingement Flow Characteristics in Direct Vessel Injection System  

SciTech Connect

Water jet impingement is a peculiar phenomenon in the APR1400 (Advanced Power Reactor 1400 MWe) in which the safety injection nozzle is located in the outer reactor vessel, not in the cold leg such as in OPR1000 (Optimized Power Reactor 1,000 MWe). Therefore, the injected emergency core coolant (ECC) water spreads with a form of parabolic liquid film in the inner barrel after impinging. It is presently considered that the downcomer flow behavior is strongly governed by the location and geometry of the water injection nozzles. The impingement in the reactor vessel downcomer is one of the unknown important phenomena during a loss-of-coolant accident (LOCA). There is thus a strong need to find how the injected flow strikes the inner downcomer wall and how wide the liquid film spreads by the impingement phenomenon. The liquid film gets in contact with the steam flow in the reactor downcomer such that the interfacial area of liquid film affects the direct bypass according to the nozzle location and geometry. The water jet impingement consists of three rather distinctive flow regions. Albeit the relevant hydrodynamic characteristics are simple and well known in simple geometries, the findings are not readily applicable in the annular reactor downcomer. Analytical and experimental approaches for impingement flow by water injection have yielded detailed flow mechanisms classified in the downcomer. The water injected through three boundaries showed varying behavior according to the injection velocity, injection nozzle diameter, wall curvature, and injection nozzle inclination. As the water injection velocity increases the liquid film spreading width increases, but the spreading width proportional to the injection velocity is tapered due to breakup. Given the injection velocity, a large diameter of injection nozzle increases the film spreading width. Impingement on the flat plate has a larger film spreading width than on the curved plate. Moreover, a larger curvature decreases the film spreading width. The inclined angle of the injection nozzle is a pivotal factor in reducing the film width by increasing the downward velocity. Given the same conditions, the film spreading width lessens as the inclined angle increases. (authors)

Yoon, Sang H. [Seoul National University and PHILOSOPHIA, Inc., San 56-1 Sillim-dong, Gwanak-gu, Seoul, 151-744 (Korea, Republic of); Suh, Kune Y. [PHILOSOPHIA, Inc., San 56-1 Sillim-dong, Gwanak-gu, Seoul, 151-744 (Korea, Republic of)

2006-07-01

140

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions.  

PubMed

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice (Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals. PMID:25163919

Cooper, Christine Elizabeth; Withers, Philip Carew

2014-10-15

141

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

PubMed

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 (I opt) 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

Minardi, Bruno Degaspari; Voytena, Ana Paula Lorenzen; Santos, Marisa; Randi, Aurea Maria

2014-01-01

142

Relationships Between Coastal Bacterioplankton Growth Rates and Biomass Production: Comparison of Leucine and Thymidine Uptake with Single-Cell Physiological Characteristics  

Microsoft Academic Search

Specific growth rates of heterotrophic bacterioplankton have been frequently estimated from in situ bacterial production (BP)\\u000a to biomass (BB) ratios, using a series of assumptions that may result in serious discrepancies with values obtained from predator-free\\u000a cultures. Here, we used both types of approaches together with a comprehensive assessment of single-cell physiological characteristics\\u000a (membrane integrity, nucleic acid content, and active

Leticia Franco-Vidal; Xosé Anxelu G. Morán

2011-01-01

143

Physiological and Anatomical Responses to Water Deficits in the CAM Epiphyte Tillandsia Ionantha (Bromeliaceae)  

E-print Network

accumulation and CO2 uptake rates did not change despite a 17% reduction in relative water content. In addition, water potentials averaged -0.40 MPa and, unlike leaf water content, did not decline. The avoidance of further declines in leaf water content...

Nowak, Edward J.; Martin, Craig E.

1997-01-01

144

Host-species-dependent physiological characteristics of hemiparasite Santalum album in association with N2-fixing and non-N2-fixing hosts native to southern China.  

PubMed

Understanding the interactions between the hemiparasite Santalum album L. and its hosts has theoretical and practical significance in sandalwood plantations. In a pot study, we tested the effects of two non-N2-fixing (Bischofia polycarpa (Levl.) Airy Shaw and Dracontomelon duperreranum Pierre) and two N2-fixing hosts (Acacia confusa Merr. and Dalbergia odorifera T. Chen) on the growth characteristics and nitrogen (N) nutrition of S. album. Biomass production of shoot, root and haustoria, N and total amino acid were significantly greater in S. album grown with the two N2-fixing hosts. Foliage and root ?(15)N values of S. album were significantly lower when grown with N2-fixing than with non-N2-fixing hosts. Significantly higher photosynthetic rates and ABA (abscisic acid) concentrations were seen in S. album grown with D. odorifera. Similarity in the proportional amounts of amino acid of root xylem sap between S. album and its host D. odorifera was also evident, suggesting major access to nitrogenous solutes from D. odorifera to S. album. Irrespective of host species, S. album clearly appeared to optimize xylem sap extraction from its hosts by higher transpiration and lower water-use efficiency than its host. The growth of two non-N2-fixing hosts parasitized by S. album was significantly greater than the equivalent values for unparasitized treatments, and lower growth and photosynthesis were observed for parasitized A. confusa, and significant decreases in root N, photosynthesis and transpiration for parasitized D. odorifera compared with unparasitized treatments. Furthermore, foliage ABA concentrations were significantly higher in all hosts parasitized by S. album than in their unparasitized counterparts. Our study is probably the first to report on host dependence and preference in the hemiparasite S. album, and the generated results may have important implications for understanding of the physiological interactions between host species and parasitic plants, and for successfully mixing plantations of S. album with D. odorifera. PMID:25216726

Lu, J K; Xu, D P; Kang, L H; He, X H

2014-09-01

145

Analysis and emulation of steady-state characteristic for water hydraulic proportional throttle valve  

Microsoft Academic Search

A new type of water hydraulic proportional throttle valve is designed. The mathematical models of steady-state control characteristic, flow characteristic and load characteristic for the new designed water hydraulic proportional throttle valve are established, in addition some main factors influencing steady-state characteristic are determined, and some steady-state characteristic analysis such as displacement initial current, flow initial current, dead zone and

Wang Xinhua; Chang Jiaqing; Wen Yanjie; Zheng Jian; Sun Shuwen

2009-01-01

146

A comparison of physiological and behavioural parameters in C57BL/6J mice undergoing food or water restriction regimes.  

PubMed

Laboratory animals, when subjected to behavioural tests, are often motivationally primed by a period of prior water or food restriction. To date, it is still debatable which restriction protocol (water versus food) is more appropriate for different species. In general, a protocol is considered appropriate if animal discomfort is kept to a minimum whilst motivation for the task is maximised. Here we present a comparison study of the effects of water versus food restriction protocols in mice. The characterisation of the physiological and behavioural effects of food and water restriction in mice is beneficial for both institutional animal care centres and the scientific community. We have investigated body weight fluctuations in three groups of C57BL/6J female mice (water-restricted, food-restricted and control) in two different protocols (20 h versus 22 h of restriction per day) over 2 consecutive weeks. Subsequently, a selected number of mice from each group were subjected to a battery of behavioural tests to investigate exploratory, emotional and dominance behaviours, in addition to learning and memory processes. Body weight fluctuations suggested that mice tolerate a water restriction regimen better than a comparable food restriction regimen. Furthermore, behavioural performances demonstrated that food-restricted mice show a reduction in the exploration of a new environment and particular aspects of their timing memories are distorted. Finally, both water- and food-restricted mice tended to be more offensive than control mice when paired with an opponent in a social dominance test condition. PMID:16870275

Tucci, Valter; Hardy, Andrea; Nolan, Patrick M

2006-10-01

147

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

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

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

2003-01-01

148

Distribution of characteristics of LWR [light water reactor] spent fuel  

SciTech Connect

The purpose of this report is to develop a collective description of the entire spent fuel inventory in terms of various fuel properties relevant to Approved Testing Materials (ATMs) using information available from the Characteristics Data Base (CBD), which is sponsored by the US Department of Energy`s (DOE`s) Office of Civilian Radioactive Waste Management. A number of light-water reactor (LWR) characteristics were analyzed including assembly class representation, fuel burnup, enrichment, fuel fabrication data, defective fuel quantities, and, at PNL`s specific request, linear heat generation rate (LHGR) and the utilization of burnable poisons. A quantitative relationships was developed between burnup and enrichment for BWRs and PWRs. The relationship shows that the existing BWR ATM is near the center of the burnup-enrichment distribution, while the four PWR ATMs bracket the center of the burnup range but are on the low side of the enrichment range. Fuel fabrication data are based on vendor specifications for new fuel. Defective fuel distributions were analyzed in terms of assembly class and vendor design. LHGR values were calculated from utility data on burnup and effective full-power days; these calculations incorporate some unavoidable assumptions which may compromise the value of the results. Only a limited amount of data are available on burnable poisons at this time. Based on this distribution study, suggestions for additional ATMs are made. These are based on the class and design concepts and include BWR/2,3 barrier fuel, and the WE 17 {times} 17 class with integral burnable poison. Both should be at relatively high burnups. 16 refs., 5 figs., 15 tabs.

Reich, W.J.; Notz, K.J. [Oak Ridge National Lab., TN (USA); Moore, R.S. [Automated Sciences Group, Inc., Oak Ridge, TN (USA)

1991-01-01

149

[Organ specific water-soluble cerebral cortex proteins; possible participation in physiological functions and pathologic manifestations].  

PubMed

The spectre of active antigens in brain is studied. The presence of 3 protein and 3 glycoprotein brain specific antigens is demonstrated. The possible participation of brain specific antigens in increased antibody formation in schizophrenics, multiple sclerosis and lateral ammiotrophic sclerosis is studied. The data obtained indicate the role of brain specific antigens to autoimmunity in those patients. The possible participation of one of the specific antigens of the brain, sialoglycoprotein GP-350, in physiological processes connected with the mechanism of memory is also studied. In experiments of inbred trained rats an activation of the synthesis of GP-350 is observed. PMID:756641

Vartanian, M E; Burbaeva, G Sh; Ignatov, S A; Nazarian, K B

1978-01-01

150

Evaluating specific error characteristics of microwave-derived cloud liquid water products  

E-print Network

Evaluating specific error characteristics of microwave-derived cloud liquid water products Thomas J errors and cloud inhomogeneity effects in cloud liquid water path (LWP) products derived from passive error characteristics of microwave-derived cloud liquid water products, Geophys. Res. Lett., 34, L22807

Christopher, Sundar A.

151

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

PubMed Central

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

Durban, J. W.; Pitman, R. L.

2012-01-01

152

[A preliminary study on the effect of irrigation on water physiology of Tamarix ramosissima in Cele oasis].  

PubMed

Change characteristics of predawn water potential, water potential daily process, and transpiration rate of Tamarix ramosissima before and after irrigation was studied in Cele oasis in the south fringe of Takelamakan Desert. The results showed that the predawn water potential (-0.93 MPa) after irrigation was higher than that before irrigation (-1.04 MPa), but there was no obvious difference. So, irrigation had certain influences on the recovery of predawn water potential of T. ramosissima. The average value of water potential daily process (-2.29 MPa) after irrigation was lower than that before irrigation (-1.69 MPa). Irrigation had no influence on the increase of water potential. The transpiration rate (0.505 mmol.m-2.s-1) after irrigation was higher than that before irrigation(0.18 mmol.m-2.s-1), and compared to the soil water content and the distribution of root system before and after irrigation, it might be resulted in underground water utilization of T. ramosissima. T. ramosissima could use the underground water with its deep root system. Surface irrigation had no significant effect on the change of water condition of T. ramosissima. PMID:12385217

Zeng, Fanjiang; Foetzki, Andrea; Li, Xiangyi; Zhang, Ximing; Li, Xiaoming; Runge, Michael

2002-07-01

153

14 CFR 25.239 - Spray characteristics, control, and stability on water.  

Code of Federal Regulations, 2013 CFR

14 Aeronautics and Space 1 2013-01-01 2013-01-01...control, and stability on water. 25.239 Section 25.239 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...AIRPLANES Flight Ground and Water Handling Characteristics...

2013-01-01

154

14 CFR 25.239 - Spray characteristics, control, and stability on water.  

Code of Federal Regulations, 2011 CFR

14 Aeronautics and Space 1 2011-01-01 2011-01-01...control, and stability on water. 25.239 Section 25.239 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...AIRPLANES Flight Ground and Water Handling Characteristics...

2011-01-01

155

14 CFR 25.239 - Spray characteristics, control, and stability on water.  

Code of Federal Regulations, 2012 CFR

14 Aeronautics and Space 1 2012-01-01 2012-01-01...control, and stability on water. 25.239 Section 25.239 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...AIRPLANES Flight Ground and Water Handling Characteristics...

2012-01-01

156

14 CFR 25.239 - Spray characteristics, control, and stability on water.  

Code of Federal Regulations, 2010 CFR

14 Aeronautics and Space 1 2010-01-01 2010-01-01...control, and stability on water. 25.239 Section 25.239 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION...AIRPLANES Flight Ground and Water Handling Characteristics...

2010-01-01

157

Salicylic acid induced physiological and biochemical changes in wheat seedlings under water stress  

Microsoft Academic Search

Salicylic acid (SA) is an important signal molecule modulating plantresponses to stress. It is recently reported to induce multiple stresstolerancein plants including drought. An experiment was, therefore, conducted toascertain the effect of salicylic acid on the growth and metabolic profile ofwheat seedlings under water stress. Irrespective of the SA concentration(1–3 mM) and water stress, SA treated plants showed, ingeneral, a

Bhupinder Singh; K. Usha

2003-01-01

158

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

Microsoft Academic Search

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

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

2011-01-01

159

[Effect of the physiological-biochemical characteristics variability on a radiosensitiveness of the Atriplex patula L. and Artemisia vulgaris L. ecoforms].  

PubMed

On the example of the physiological and the cytology-biochemical characteristics variability of an Atriplex patula L. and Artemisia vulgaris L. sprouts which parental plants were generated in various environmental conditions (South Yakutia, the Central Yakutia, Middle Ural), was shown, that radiostability depends not only on set protective antioxidant, on the DNA-reparation systems and on the vulnerability degree of a functioning genome, but also on the phenotypic diversifications of a population which in turn, in the certain degree, are consequence of previous selection of a population to all set of ecological stresses-factors of the environment. PMID:16579547

Zhuravskaia, A N; Voronov, I V; Prokop'ev, I A

2006-01-01

160

Separation characteristics of multistage water/hydrogen exchange column for water detritiation in fusion reactors  

SciTech Connect

A simulation code of multistage chemical exchange columns has been developed. The sieve trays for liquid-vapor scrubbing and the catalyst beds for vapor-hydrogen exchange reactions are alternately piled within the column. The code deals with all the twelve molecular species of hydrogen gas and water; and is based on the Newton-Raphson method. The characteristics of the column were discussed from the calculated results by this code such as effects of temperature and pressure. Similar to the distillation columns, the phase flow rates within the column (hydrogen gas and water vapor) and product flow rates have large effects on the separation performance of the column. A control method of the column was also proposed from these calculated results. 9 refs., 5 figs., 4 tabs.

Yamanishi, T.; Okuno, K. [Japan Atomic Energy Research Lab., Ibaraki (Japan)

1995-10-01

161

Anatomical and physiological regulation of post-fire carbon and water exchange in canopies of two resprouting Eucalyptus species.  

PubMed

The great majority of Eucalyptus spp. are facultative resprouters, and they dominate the eucalypt forests of Australia. Despite this numeric and geographic dominance, there is a general lack of knowledge of their capacity for carbon capture and water loss during canopy reinstation. After a crown-removing fire, we measured leaf-level determinants of carbon and water flux in resprouting canopies of Eucalyptus dives and E. radiata over the 3 years that followed. Leaf anatomy and physiology changed markedly during canopy reinstation, and leaves produced in the second year (2010) were distinct from those produced later. Leaves produced in 2010 were thicker (all measures of leaf anatomy), yet more porous (increased intercellular airspace), causing specific leaf area also to be greater. Indicators of heterotrophic activity, leaf respiration rate and light compensation point, were twofold greater in 2010, whereas all measures of photosynthetic capacity were greatest in leaves produced in 2011 and 2012. Whilst stomatal density, vein density and leaf hydraulic conductance all progressively decreased with time, neither leaf water status nor carbon isotope discrimination were affected. We conclude that canopy reinstation is primarily limited by pre-fire carbon stores, rather than by post-fire edaphic conditions (e.g., water availability), and thus argue that capacity for recovery is directly linked to pre-fire forest health. PMID:25108550

Turnbull, Tarryn L; Buckley, Thomas N; Barlow, Alexandra M; Adams, Mark A

2014-10-01

162

Water flow and hydraulic characteristics of Japanese red pine and oak trees  

Microsoft Academic Search

To assess the characteristics of water flow in a tree and the contribution of the stem water storage to transpiration, some field observations were carried out in two natural forests: a Japanese red pine (Pinus densiflora Sieb. et Zucc.) forest and an oak (Quercus mongolica Fish) forest. Water potentials of leaf, stem, root and soil water, sap flow rate, volumetric

Yoshikazu Kobayashi; Tadashi Tanaka

2001-01-01

163

Environmental physiology of the mangrove rivulus, Kryptolebias marmoratus, a cutaneously breathing fish that survives for weeks out of water.  

PubMed

The mangrove rivulus (Kryptolebias marmoratus) is an excellent model species for understanding the physiological mechanisms that fish use in coping with extreme environmental conditions, particularly cutaneous exchange during prolonged exposure to air. Their ability to self-fertilize and produce highly homozygous lineages provides the potential for examining environmental influences on structures and related functions without the complications of genetic variation. Over the past 10 years or so, we have gained a broader understanding of the mechanisms K. marmoratus use to maintain homeostasis when out of water for days to weeks. Gaseous exchange occurs across the skin, as dramatic remodeling of the gill reduces its effective surface area for exchange. Ionoregulation and osmoregulation are maintained in air by exchanging Na(+), Cl(-), and H(2)O across skin that contains a rich population of ionocytes. Ammonia excretion occurs in part by cutaneous NH(3) volatilization facilitated by ammonia transporters on the surface of the epidermis. Finally, new evidence indicates that cutaneous angiogenesis occurs when K. marmoratus are emersed for a week, suggesting a higher rate of blood flow to surface vessels. Taken together, these and other findings demonstrate that the skin of K. marmoratus takes on all the major functions attributed to fish gills, allowing them to move between aquatic and terrestrial environments with ease. Future studies should focus on variation in response to environmental changes between homozygous lineages to identify the genetic underpinnings of physiological responses. PMID:22693260

Wright, Patricia A

2012-12-01

164

SOME PHYSIOLOGICAL RESPONSES OF CANOLA (BRASSICA NAPUS L.) TO WATER DEFICIT STRESS UNDER LABORATORY CONDITIONS  

Microsoft Academic Search

Drought is considered as one of the most important limiting factors for oil seed canola plant (Brassica napus L.) growth and productivity in Iran. On the basis of root and shoot dry weight as affected by water stress exerted by PEG 6000, out of 9 canola cultivars, a relatively tolerant (cv. Aghaii) and a sensitive cultivar (cv. PO4) were selected.

A. MORADSHAHI; B. SALEHI ESKANDARI; B. KHOLDEBARIN

165

Plant physiology Role of awns in ear water-use efficiency  

E-print Network

net photosynthesis and water-use efficiency (WUE: net photosynthesis/transpiration) of ears and flag leaves were measured 3 times during grain filling: 1, 3 and 4 weeks after anthesis. The total photosynthesis of awned ears was markedly higher than that of awnless ears, until 3 weeks after anthesis

Paris-Sud XI, Université de

166

Genome duplication and the evolution of physiological responses to water stress  

E-print Network

-8137.2009.02997.x Key words: adaptation, Chamerion angustifolium, gas exchange, hydraulic conductance, polyploidy differentiation between cytotypes is not known. · We examined the water relations of Chamerion angustifolium C. angustifolium are unlikely to be caused solely by genome duplication. The enhanced ability

Maherali, Hafiz

167

Water hammer simulation by implicit method of characteristic  

Microsoft Academic Search

An Implicit Method of Characteristics is proposed in this paper to alleviate the shortcomings and limitations of the mostly used conventional Method of Characteristics (MOC). An element-wise definition is used for all the devices that may be used in a pipeline system and the corresponding equations are derived in an element-wise manner. The proper equations defining the behavior of each

M. H. Afshar; M. Rohani

2008-01-01

168

Combustion characteristics of nanoaluminum, liquid water, and hydrogen peroxide mixtures  

SciTech Connect

An experimental investigation of the combustion characteristics of nanoaluminum (nAl), liquid water (H{sub 2}O{sub (l)}), and hydrogen peroxide (H{sub 2}O{sub 2}) mixtures has been conducted. Linear and mass-burning rates as functions of pressure, equivalence ratio ({phi}), and concentration of H{sub 2}O{sub 2} in H{sub 2}O{sub (l)} oxidizing solution are reported. Steady-state burning rates were obtained at room temperature using a windowed pressure vessel over an initial pressure range of 0.24 to 12.4 MPa in argon, using average nAl particle diameters of 38 nm, {phi} from 0.5 to 1.3, and H{sub 2}O{sub 2} concentrations between 0 and 32% by mass. At a nominal pressure of 3.65 MPa, under stoichiometric conditions, mass-burning rates per unit area ranged between 6.93 g/cm{sup 2} s (0% H{sub 2}O{sub 2}) and 37.04 g/cm{sup 2} s (32% H{sub 2}O{sub 2}), which corresponded to linear burning rates of 9.58 and 58.2 cm/s, respectively. Burning rate pressure exponents of 0.44 and 0.38 were found for stoichiometric mixtures at room temperature containing 10 and 25% H{sub 2}O{sub 2}, respectively, up to 5 MPa. Burning rates are reduced above {proportional_to}5 MPa due to the pressurization of interstitial spaces of the packed reactant mixture with argon gas, diluting the fuel and oxidizer mixture. Mass burning rates were not measured above {proportional_to}32% H{sub 2}O{sub 2} due to an anomalous burning phenomena, which caused overpressurization within the quartz sample holder, leading to tube rupture. High-speed imaging displayed fingering or jetting ahead of the normal flame front. Localized pressure measurements were taken along the sample length, determining that the combustion process proceeded as a normal deflagration prior to tube rupture, without significant pressure buildup within the tube. In addition to burning rates, chemical efficiencies of the combustion reaction were determined to be within approximately 10% of the theoretical maximum under all conditions studied. (author)

Sabourin, J.L.; Yetter, R.A. [The Pennsylvania State University, Department of Mechanical and Nuclear Engineering, University Park, PA 16801 (United States); Risha, G.A. [The Pennsylvania State University, Division of Business and Engineering, Altoona, PA 16601 (United States); Son, S.F. [Purdue University, School of Mechanical Engineering, West Lafayette, IN 47907 (United States); Tappan, B.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2008-08-15

169

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

PubMed

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

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

2013-01-01

170

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

PubMed Central

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

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

2013-01-01

171

[Leaf morphological structure and physiological and biochemical characteristics of female and male Hippophae rhamnoides subsp. sinensis under different soil moisture condition].  

PubMed

A field experiment was conducted to study the leaf morphological structure and physiological and biochemical characteristics of female and male Hippophae rhamnoides subsp. sinensis under different soil moisture condition. When the soil moisture condition was poorer, the leaf structure of the plants displayed distinct xeromorphic characteristics, being more obvious for the female plants. Comparing with those of male plants, the leaf thickness, thickness of upper and lower epidermis, and the distance between lateral vein bundles of female plants were smaller, while the thickness and density of lower epidermis hairs and the ratio of palisade tissue thickness to sponge tissue thickness were in adverse, indicating that female plants had stronger drought adaptability and greater ecological plasticity. With the decrease of soil moisture content, the leaf dissociative proline, dissoluble sugar, and malonaldehyde (MDA) contents of both male and female plants all increased, but for female plants, the increment of their leaf dissociative proline and dissoluble sugar contents was larger, while that of MDA content was smaller than the male plants. With the changes of soil moisture content, the leaf superoxide dismutase and catalase activities of the plants varied greatly, but had no regular pattern. Under the stress of soil drought, the values of multivariate membership function of test parameters were larger for the female than the male plants, suggesting that the female plants of H. rhamnoides subsp. sinensis had stronger physiological regulation capability and greater adaptability to drought stress. PMID:21265138

Gao, Li; Yang, Jie; Liu, Rui-xiang

2010-09-01

172

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

PubMed

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

Shu, Xiao; Zhang, QuanFa; Wang, WeiBo

2014-11-01

173

Uptake and physiological response of crop plants irrigated with water containing RDX and TNT  

SciTech Connect

Regulatory agencies have expressed concern about possible bioconcentration of TNT (2,4,6-trinitrotoluene) and RDX (cyclotrimethylenetrinitramine) in food and forage crops irrigated with contaminated groundwater. Field and home-garden crops grown in site-collected soil were irrigated with water containing RDX and TNT to simulate field conditions at Cornhusker Army Ammunition Plant (CAAP), Nebraska. Pots were watered in an environment-controlled greenhouse to field capacity throughout the life-cycle of each crop with 2, 20, and 100 ppb RDX; 2, 100, and 800 ppb TNT; 100 ppb RDX + 800 ppb TNT; or uncontaminated water in response to evapo-transpirative demand. Uptake of RDX in lettuce leaves, corn stover, and alfalfa shoots was positively correlated with treatment level, however, concentrations of RDX in these crops were generally equal to or below soil loading concentrations. RDX was not significantly (p = 0.05) taken up into tomato fruit, bush bean seeds and pods, radish roots, and soybean seeds. TNT was not significantly take up into tissues of any of the crops analyzed in this study. Yield and biomass of tomato fruit, bush bean fruit, corn stover, and soybean seeds were significantly (p = 0.05) less when irrigated with the RDX + TNT treatment compared to controls. Lettuce leaf, radish root, and alfalfa shoot yield and biomass were unaffected by treatment level. For site-specific criteria used in this study, RDX and TNT did not bioconcentrate in edible plant tissues. This is the first controlled study to investigate uptake of RDX and TNT in crops irrigated with water containing explosives concentrations commonly found in contaminated groundwater.

Simini, M. [Geo-Centers, Inc., Aberdeen Proving Ground, MD (United States); Checkai, R.T.

1995-12-31

174

Varietal variation and physiological basis for inhibition of wheat seed germination after excessive water treatment  

Microsoft Academic Search

Soaking the seeds of most upland plants in water before sowing results in poor germination. Varietal differences in flooding\\u000a tolerance of seeds have been reported in maize, soybean, barley and so on. This study was conducted to evaluate the varietal\\u000a difference in wheat (2n = 42) seeds to soaking injury and to examine the importance of ethanol accumulation and seed

Kihachi Ueno; Hidekazu Takahashi

1997-01-01

175

REGIONAL CHARACTERISTICS AND WATER ISSUES: FROM MEKONG RIVER BASIN PERSPECTIVES  

Microsoft Academic Search

Water plays a very important part in the social, economic and cultural life, and the religious belief of the people of the Mekong region. Challenges faced by Mekong Basin countries in their endeavours for economic development are increasingly related to water. The Mekong River with its length of over 4,800 km is one of the longest and largest rivers in

SOKHEM PECH

176

Zamzam water: Concentration of trace elements and other characteristics  

Microsoft Academic Search

Many Muslims drink Zamzam water for use either medicinally or religiously. Millions of pilgrims drink it and take bottles of it to their home countries. Heated scientific and political debates appeared after BBC reported in May 2011 that Zamzam water is poisonous, because of the high levels of arsenic. The World Health Organizations classifies arsenic as a human carcinogen, but

Basem Shomar

177

Characteristics of discharged sea water generated by underwater plasma system  

Microsoft Academic Search

Discharge to sea water is very hard and require considerable high voltage. But specially designed electrode can support plasma discharge to saline water with relatively low voltage. The round-shaped ceramic electrode having a lot of pinhole combined with metallic one was developed. Different types of electrodes were tested by changing number of hole and diameter of hole. The operating conditions

S. M. Ryu; E. J. Hong; D. C. Seok; S. R. Yoo; Y. J. Kim; T. Lho; B. J. Lee

178

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

PubMed

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

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

2010-03-01

179

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

SciTech Connect

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.

Tsai, Baolong.

1989-01-01

180

Effect of sweet wormwood Artemisia annua crude leaf extracts on some biological and physiological characteristics of the lesser mulberry pyralid, Glyphodes pyloalis.  

PubMed

The lesser mulberry pyralid, Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is a monophagous and dangerous pest of mulberry that has been recently observed in Guilan province, northern Iran. In this study, the crude methanol extract of sweet wormwood Artemisia annua L. (Asterales: Asteracaea) was investigated on toxicity, biological and physiological characteristics of this pest under controlled conditions (24 ± 1 °C, 75 ± 5% RH, and 16:8 L:D photoperiod). The effect of acute toxicity and sublethal doses on physiological characteristics was performed by topical application. The LC?? and LC?? values on fourth instar larvae were calculated as 0.33 and 0.22 gram leaf equivalent/ mL, respectively. The larval duration of fifth instar larvae in LC?? treatment was prolonged (5.8 ± 0.52 days) compared with the control group (4.26 ± 0.29 days). However larval duration was reduced in the LC?? treatment. The female adult longevity in the LC?? dose was the least (4.53 ± 0.3 days), while longevity among controls was the highest (9.2 ± 0.29 days). The mean fecundity of adults after larval treatment with LC?? was recorded as 105.6 ± 16.84 eggs/female, while the control was 392.74 ± 22.52 eggs/female. The percent hatchability was reduced in all treatments compared with the control. The effect of extract in 0.107, 0.053, 0.026 and 0.013 gle/mL on biochemical characteristics of this pest was also studied. The activity of ?-amylase and protease 48 hours post-treatment was significantly reduced compared with the control. Similarly lipase, esterase, and glutathione S-transferase activity were significantly affected by A. annua extract. PMID:22239100

Khosravi, Roya; Sendi, Jalal Jalali; Ghadamyari, Mohammad; Yezdani, Elham

2011-01-01

181

Effect of Sweet Wormwood Artemisia annua Crude Leaf Extracts on Some Biological and Physiological Characteristics of the Lesser Mulberry Pyralid, Glyphodes pyloalis  

PubMed Central

The lesser mulberry pyralid, Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is a monophagous and dangerous pest of mulberry that has been recently observed in Guilan province, northern Iran. In this study, the crude methanol extract of sweet wormwood Artemisia annua L. (Asterales: Asteracaea) was investigated on toxicity, biological and physiological characteristics of this pest under controlled conditions (24 ± 1 °C, 75 ± 5% RH, and 16:8 L:D photoperiod). The effect of acute toxicity and sublethal doses on physiological characteristics was performed by topical application. The LC50 and LC20 values on fourth instar larvae were calculated as 0.33 and 0.22 gram leaf equivalent/ mL, respectively. The larval duration of fifth instar larvae in LC50 treatment was prolonged (5.8 ± 0.52 days) compared with the control group (4.26 ± 0.29 days). However larval duration was reduced in the LC20 treatment. The female adult longevity in the LC50 dose was the least (4.53 ± 0.3 days), while longevity among controls was the highest (9.2 ± 0.29 days). The mean fecundity of adults after larval treatment with LC50 was recorded as 105.6 ± 16.84 eggs/female, while the control was 392.74 ± 22.52 eggs/female. The percent hatchability was reduced in all treatments compared with the control. The effect of extract in 0.107, 0.053, 0.026 and 0.013 gle/mL on biochemical characteristics of this pest was also studied. The activity of ?-amylase and protease 48 hours post—treatment was significantly reduced compared with the control. Similarly lipase, esterase, and glutathione S-transferase activity were significantly affected by A. annua extract. PMID:22239100

Khosravi, Roya; Sendi, Jalal Jalali; Ghadamyari, Mohammad; Yezdani, Elham

2011-01-01

182

The function of 7D-cadherins: a mathematical model predicts physiological importance for water transport through simple epithelia  

PubMed Central

Background 7D-cadherins like LI-cadherin are cell adhesion molecules and represent exceptional members of the cadherin superfamily. Although LI-cadherin was shown to act as a functional Ca2+-dependent adhesion molecule, linking neighboring cells together, and to be dysregulated in a variety of diseases, the physiological role is still enigmatic. Interestingly 7D-cadherins occur only in the lateral plasma membranes of cells from epithelia of water transporting tissues like the gut, the liver or the kidney. Furthermore LI-cadherin was shown to exhibit a highly cooperative Ca2+-dependency of the binding activity. Thus it is tempting to assume that LI-cadherin regulates the water transport through the epithelium in a passive fashion by changing its binding activity in dependence on the extracellular Ca2+. Results We developed a simple mathematical model describing the epithelial lining of a lumen with a content of variable osmolarity covering an interstitium of constant osmolarity. The width of the lateral intercellular cleft was found to influence the water transport significantly. In the case of hypertonic luminal content a narrow cleft is necessary to further increase concentration of the luminal content. If the cleft is too wide, the water flux will change direction and water is transported into the lumen. Electron microscopic images show that in fact areas of the gut can be found where the lateral intercellular cleft is narrow throughout the lateral cell border whereas in other areas the lateral intercellular cleft is widened. Conclusions Our simple model clearly predicts that changes of the width of the lateral intercellular cleft can regulate the direction and efficiency of water transport through a simple epithelium. In a narrow cleft the cells can increase the concentration of osmotic active substances easily by active transport whereas if the cleft is wide, friction is reduced but the cells can hardly build up high osmotic gradients. It is now tempting to speculate that 7D-cadherins, owing to their location and their Ca2+-dependence, will adapt their binding activity and thereby the width of the lateral intercellular cleft automatically as the Ca2+-concentration is coupled to the overall electrolyte concentration in the lateral intercellular cleft. This could provide a way to regulate the water resorption in a passive manner adapting to different osmotic conditions. PMID:21663598

2011-01-01

183

Physiological skin surface water loss dynamics of human vulvar and forearm skin.  

PubMed

In order to estimate the influence of occlusion and sweating on forearm and vulvar skin surface water loss (SSWL), both were measured simultaneously and continuously for 30 min in 8 healthy women. Vulvar SSWL decreased significantly during the measuring period from 24.9 +/- 5.2 gm-2 h-1 (mean +/- standard error of the mean) in the first 5 min, to 13.4 +/- 1.7 gm-2 h-1 in the last 5 min (p less than 0.05), whereas no significant changes were observed in forearm SSWL. The vulvar SSWL decay curve followed a logarithmic equation of the form y = a*tb. Irregular SSWL increases ('bursts') were observed in vulvar (but not in forearm) skin of 7 out of 8 women. These SSWL bursts were considered to be caused by sweating. The study shows possible causes of systematic errors in vulvar irritation studies. Methods for error reduction are discussed. PMID:1969199

Elsner, P; Wilhelm, D; Maibach, H I

1990-01-01

184

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

PubMed Central

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

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

2009-01-01

185

Impact of Natural Conditioners on Water Retention, Infiltration and Evaporation Characteristics of Sandy Soil  

Microsoft Academic Search

Soil conditioners i.e., natural deposits and organic fertilizer are used for alleviate some of poor physical properties of sandy soils such as low water retention and inefficient water use, especially in arid and semi-arid regions such as in Saudi Arabia conditions. The present study aims to investigate the impact of clay deposits and organic fertilizer on water characteristics, cumulative infiltration

G. Abdel-Nasser; A. M. Al-Omran; A. M. Falatah; A. S. Sheta; A. R. Al-Harbi

2007-01-01

186

[The health, hygienic and toxicological characteristics of the natural water from the upper Volga].  

PubMed

The paper provides sanitary and toxicological water characteristics in the city of Yaroslavl on the Volga River in 1993-1996. The water was shown to contain high levels of petroleum products, COD, and toxic substances. The water concentrations of phenol were no greater than the acceptable values. Those of metals, pesticides, and detergents did not exceed the sanitary standards. PMID:10199068

Flerov, B A; Koroleva, E K

1999-01-01

187

Desert shrub water relations with respect to soil characteristics and plant functional type  

Microsoft Academic Search

Summary 1. Soil characteristics influence plant communities in part through water relations. Hypothetically, finer textured soils in arid climates should be associated with more negative plant and soil water potentials during drought, greater resistance of xylem to cavitation, and shallower root systems than coarse soils. 2. These hypotheses were tested by comparing the water relations of Great Basin shrubs growing

J. S. Sperry; U. G. Hacke

2002-01-01

188

Characteristics and variability of the Indonesian throughflow water at the outflow straits  

E-print Network

and is related to the supply of fresh near-surface Java Sea water that is drawn eastward by surface monsoonCharacteristics and variability of the Indonesian throughflow water at the outflow straits Agus 2009 Accepted 17 June 2009 Available online 24 June 2009 Keywords: Indonesian throughflow water

Sprintall, Janet

189

Water management studies in PEM fuel cells, part III: Dynamic breakthrough and intermittent drainage characteristics from  

E-print Network

drainage characteristics from GDLs with and without MPLs Zijie Lu, Michael M. Daino, Cody Rath, Satish G Water management Gas diffusion layer Water transport Dynamic breakthrough Intermittent drainage a b of an intermittent water drainage mechanism in the GDL. This is accounted for by the breakdown and redevelopment

Kandlikar, Satish

190

WATER TEMPERATURE CHARACTERISTICS OF LAKES SUBJECTED TO CLIMATE CHANGE  

EPA Science Inventory

A deterministic, one dimensional, unsteady lake water temperature model was modified and validated to simulate the seasonal (spring to fall) temperature stratification structure over a wide range of lake morphometries, trophic and meteorological conditions. odel coefficients rela...

191

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...

192

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...

193

Zamzam water: concentration of trace elements and other characteristics.  

PubMed

Many Muslims drink Zamzam water for use either medicinally or religiously. Millions of pilgrims drink it and take bottles of it to their home countries. Heated scientific and political debates appeared after BBC reported in May 2011 that Zamzam water is poisonous, because of the high levels of arsenic. The World Health Organizations classifies arsenic as a human carcinogen, but some types of arsenic are also used as medicines. Adequate scientific studies on the Zamzam water are absent. This paper will provide, for the first time, basic and comprehensive information regarding the geochemical properties of Zamzam water for more than 30 indicators and using the state-of-the-art laboratory facilities. The data will help us to understand the sources of pollution under discussion, reactions at both local and international levels; and will highlight the potential healing capacity of Zamzam water. Thirty Zamzam water samples were collected by three distinct methods; from 10 pilgrims living in different locations in Germany in 2007, 10 samples from shops in Frankfurt and Berlin in 2011, and 10 samples directly from Makkah in 2011. The samples were analyzed 2 weeks after collection for more than 30 indicators: pH, EC, Eh, Cl, F, Br, NO(3), PO(4), SO(4), HCO(3), Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn beside others. Four major instruments were used; the IC, the ICPOES, the ICPMS and the HGAAS. The quality of the water did not change for 2 years and there was an excellent agreement among the results of the 30 water samples as well as between the results of the 2 years for the same samples analyzed in 2007 and 2008. The water is alkaline (average pH is 8) with an average Li concentration of 15 ?g L(-1). The average concentrations of As and NO(3) showed values three times higher than the WHO standards (27 ?g L(-1) and 150 mg L(-1), respectively). The averages of Ca and K were 95 and 50 mg L(-1), respectively. Very urgent steps are required to scientifically screen for the elevated parameters As, NO(3), Ca, and K in all Zamzam water sources and locations with full transparency. The resultant information should be made available to the public, and the relationship between pollution and human health should be addressed. The alkalinity of Zamzam water and the presence of trace amounts of As and Li may cause the healing power. However, a scientific strategy should be developed and adopted to enable further research and studies on toxicology and treatment technologies could be applied if needed. PMID:22138338

Shomar, Basem

2012-02-01

194

Combustion characteristics of heavy oil-water emulsions  

Microsoft Academic Search

The combustion of heavy oil and its emulsions with water was investigated in experiments on a semi-industrial scale. Two comparisons between heavy oil and oil-water emulsion flames are presented that, due to the different initial conditions of the spray, provide complementary information. Reported results include spatial distributions in the flame of temperature and species concentrations (O2, CO, UHC, NOx) as

Javier M. Ballester; Norberto Fueyo; César Dopazo

1996-01-01

195

WATER ADSORPTION AND DRYING CHARACTERISTICS OF OKRA Hibiscus Esculentus L  

Microsoft Academic Search

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.

FAHRETTIN GÖGUS; MEDENI MASKAN

1999-01-01

196

Dynamic characteristics of mixtures of plutonium, Nevada tuff, and water  

SciTech Connect

One of the technical options being considered for long term disposition of weapons grade plutonium is geologic storage at Yucca Mountain. Multikilogram quantities of plutonium are to be vitrified, placed within a heavy steel container, and buried in the material know as Nevada tuff. It has been postulated that after ten thousand years, geologic and chemical processes would have disintegrated the steel container and created the possibility for plutonium to form mixtures with Nevada tuff and water that could lead to a nuclear explosion in the range of kilotons. A survey and description of critical homogeneous mixtures of plutonium, silicon dioxide, Nevada tuff, and water which also identified the mixture regimes where autocatalytic dynamic behavior is possible was completed. This study is a follow up of this survey and the major objective is to examine the dynamic behavior of the worst case critical and supercritical configurations of plutonium, water and Nevada tuff.

Myers, W.; Rojas, S.; Kimpland, R.H.; Jaegers, P.J.; Sanchez, R.G.; Hayes, D.; Paternoster, R.; Anderson, R.; Stratton, W.

1996-02-01

197

Environmental impact of leachate characteristics on water quality.  

PubMed

Improper urbanization and industrialization are causing a critical stress on groundwater quality in urban areas of the developing countries. The present study under investigation describes the pollution caused by leachate from a waste management site in southwestern Bangalore city causing pollution of the surface water and groundwater reserves. The characterization of 20 groundwater samples and Haralukunte lake sample indicated high pollution of these water reserves by leachate entry into the groundwater and surface water sources. The study area focuses around the solid waste management site, carrying out bio-composting and vermi-composting of municipal solid waste. Further investigations on the severe health problems faced by the public in the study area has revealed a clear pointer towards the usage of polluted water for rearing live-stock, farming, and domestic activities. The characterization of the leachate with high values of BOD at 1,450 mg/l, TDS at 17,200 mg/l, nitrates at 240 mg/l, and MPN at 545/100 ml indicates a clear nuisance potential, which has been substantiated by the characterization of lake water sample with chlorides at 3,400 mg/l, TDS at 8,020 mg/l, and lead and cadmium at 0.18 and 0.08 mg/l, respectively. Analysis of groundwater samples shows alarming physicochemical values closer to the waste disposal site and relatively reduced values away from the source of the waste management site. Bureau of Indian Standards have been adapted as the benchmark for the analysis and validation of observed water quality criteria. PMID:20859680

Cumar, Sampath Kumar Mandyam; Nagaraja, Balasubramanya

2011-07-01

198

Characteristics of Large Volume Discharges in Water using Pulsed Power  

Microsoft Academic Search

One of industrial applications using pulsed power technologies is water treatment by streamer discharges. Streamer discharges in liquid generate high electric fields at the tip of streamers, as well as high-energy electrons, ozone, chemically active species, ultraviolet rays and shock waves. All of these may be utilized to sterilize microorganisms and to decompose molecules and materials. Large volume streamer discharges

Hiroshi Nakashi; Tatsuya Hirooka; Sunao Katsuki; Hidenori Akiyama

2003-01-01

199

Water sorption isotherms of starch powders. Part 2: Thermodynamic characteristics  

Microsoft Academic Search

A thermodynamic approach was used to interpret the experimental adsorption and desorption isotherm data for potato, highly amylopectin and highly amylose powders starch. Calculation of the thermodynamic properties (differential enthalpy, integral enthalpy, differential entropy and integral entropy) provides an understanding of the properties of water and energy requirements associated with the sorption behaviour. The isosteric heat of sorption (differential enthalpy)

A. H Al-Muhtaseb; W. A. M McMinn; T. R. A Magee

2004-01-01

200

The Beneficial Acclimation Hypothesis versus Acclimation of Specific Traits: Physiological Change in Water-Stressed [ITAL]Manduca sexta[\\/ITAL] Caterpillars  

Microsoft Academic Search

Do organisms make beneficial physiological adjustments in re- sponse to environmental change? We examined this question by measuring the effects of short-term (12-36 h) and long- term (larval lifetime) hydric stress on the tobacco hornworm, Manduca sexta. Larvae were reared from the first instar on low- water (69%) or high-water (80%) artificial diets and then trans- ferred early in the

H. Arthur Woods; Jon F. Harrison

2001-01-01

201

Characteristics of hydrogen bond revealed from water clusters  

NASA Astrophysics Data System (ADS)

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. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-50027-5

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

2014-09-01

202

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)

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.

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

2014-05-01

203

MUTAGENIC CHARACTERISTICS OF RIVER WATERS FLOWING THROUGH LARGE METROPOLITAN AREAS IN NORTH AMERICA  

EPA Science Inventory

Mutagenic characteristics of river waters flowing through large metropolitan areas in North America The hanging technique using blue rayon, which specifically adsorbs mutagens with multicyclic planar structures, has the advantages over most conventional methods of not havi...

204

Characteristics of RO foulants in a brackish water desalination plant  

Microsoft Academic Search

This study identified the membrane fouling of a two-stage RO process of the Bai-sha brackish water desalination plant facing serious fouling problems. Two membrane modules, one from each stage, were autopsied and diagnosed for the cause for the failure of the RO system. Different morphologies were exhibited on the fouled membrane. Results suggested that the fouling on the first-stage membrane

Hui Ling Yang; Chihpin Huang; Jill R. Pan

2008-01-01

205

Developing joint probability distributions of soil water retention characteristics  

Microsoft Academic Search

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

Robert F. Carsel; Rudolph S. Parrish

1988-01-01

206

Characteristics of water-soluble fiber manufactured from carboxymethylcellulose synthesis  

Microsoft Academic Search

Carboxymethylcellulose (CMC), which is water-soluble fiber at room temperature, was manufactured from cellulose in this study.\\u000a Experimental parameters included reaction temperature, time, concentration of NaOH, and monochloroacetic acid. In mercerization\\u000a and etherification, the solubility and DS increased when NaOH (or MCA) concentration increased, and maximum solubility and\\u000a DS were achieved when NaOH or MCA was 30%. The effect of MCA

Youngmin Choi; Sanjeev Maken; Seungmoon Lee; Euihyun Chung; Byoungryul Min

2007-01-01

207

Water Purification Using the Adsorption Characteristics of Microbubbles  

NASA Astrophysics Data System (ADS)

Recently, technology using microbubbles has been studied for water purification. However, the mechanism and physical parameters of the purification process have not yet been sufficiently clarified. The purpose of this study is to clarify the physical parameters of microbubbles that influence water purification. Firstly, we measured and analyzed the purifying performance using various millimeter-sized bubbles, and we obtained the equilibrium constant of the pollutant adsorbed on the bubble surface from the experimental results. Secondly, we experimented with purifying the polluted water using microbubbles and clarified that the purification performance of microbubbles agreed with that theoretically expected using the equilibrium constant obtained in the preparatory experiment. We assume that an important parameter affecting adsorption on the surface of microbubbles is the equilibrium constant in the chemical potential. Because the equilibrium constant is derived from the surface chemical potential, it is equal to the bulk chemical potential of the liquid. In the microbubbles diameter (70 µm) range in this study, we have found that the most significant factor determining the adsorption is the surface area. The surface tension of microbubbles is not significant factor.

Yoshida, Akira; Takahashi, Osamu; Ishii, Yorishige; Sekimoto, Yoshihiro; Kurata, Yukio

2008-08-01

208

Adsorption characteristics of water vapor on honeycomb adsorbents  

NASA Astrophysics Data System (ADS)

Recovery of tritium released into working areas in nuclear fusion plants is a key issue of safety. A large volume of air from tritium fuel cycle or vacuum vessel should be processed by air cleanup system (ACS). In ACS, tritium gas is oxidized by catalysts, and then tritiated water vapor is collected by adsorbents. This method can remove tritium effectively, whereas high throughput of air causes high-pressure drop in catalyst and adsorbent beds. In this study, the applicability of honeycomb-type adsorbents, which offers a useful advantage in terms of their low-pressure drop, to ACS was examined, in comparison with conventional pebble-type adsorbent. Honeycomb-type adsorbent causes far less pressure drop than pebble-type adsorbent beds. Adsorption capacity of water vapor on a honeycomb-type adsorbent is slightly lower than that on a pebble-type adsorbent, while adsorption rate of water vapor on honeycomb-type adsorbent is much higher than that of pebble-type adsorbent.

Wajima, Takaaki; Munakata, Kenzo; Takeishi, Toshiharu; Hara, Keisuke; Wada, Kouhei; Katekari, Kenichi; Inoue, Keita; Shinozaki, Yohei; Mochizuki, Kazuhiro; Tanaka, Masahiro; Uda, Tatsuhiko

2011-10-01

209

Genotype-environment interactions affecting preflowering physiological and morphological traits of Brassica rapa grown in two watering regimes.  

PubMed

Plant growth and productivity are greatly affected by drought, which is likely to become more threatening with the predicted global temperature increase. Understanding the genetic architecture of complex quantitative traits and their interaction with water availability may lead to improved crop adaptation to a wide range of environments. Here, the genetic basis of 20 physiological and morphological traits is explored by describing plant performance and growth in a Brassica rapa recombinant inbred line (RIL) population grown on a sandy substrate supplemented with nutrient solution, under control and drought conditions. Altogether, 54 quantitative trait loci (QTL) were identified, of which many colocated in 11 QTL clusters. Seventeen QTL showed significant QTL-environment interaction (Q×E), indicating genetic variation for phenotypic plasticity. Of the measured traits, only hypocotyl length did not show significant genotype-environment interaction (G×E) in both environments in all experiments. Correlation analysis showed that, in the control environment, stomatal conductance was positively correlated with total leaf dry weight (DW) and aboveground DW, whereas in the drought environment, stomatal conductance showed a significant negative correlation with total leaf DW and aboveground DW. This correlation was explained by antagonistic fitness effects in the drought environment, controlled by a QTL cluster on chromosome A7. These results demonstrate that Q×E is an important component of the genetic variance and can play a great role in improving drought tolerance in future breeding programmes. PMID:24474811

El-Soda, Mohamed; Boer, Martin P; Bagheri, Hedayat; Hanhart, Corrie J; Koornneef, Maarten; Aarts, Mark G M

2014-02-01

210

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

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.

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

211

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

PubMed

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

Palen, Wendy J; Schindler, Daniel E

2010-05-25

212

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

PubMed Central

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

Palen, Wendy J.; Schindler, Daniel E.

2010-01-01

213

[Female physiology during exercise].  

PubMed

Physiological responses and adaptations of women to exercise are influenced by her genetically determined morphological and functional characteristics, and by her level of physical fitness. Physiological responses of women during submaximal and maximal exercise differ quantitatively from those of men but adaptations to training are qualitatively similar in both. Studies demonstrate that differences between the sexes in performance of athletic events that require high aerobic or anaerobic capacity are due, to a large extent, to differences in body structure and composition: the average woman is smaller and lighter and has less muscle mass than the average man. These characteristics influence physiologic responses of the musculoskeletal, cardiovascular and respiratory systems during exercise. This article describes physiological responses of women during exercise in relation to her sex related morphological characteristics, and the adaptations that occur with physical training. PMID:2270262

Rivera Brown, A M

1990-04-01

214

A new Automated Laboratory Instrument for Soil Water Characteristic Determination. System Validation at Oregon State University  

Microsoft Academic Search

The soil water characteristic (SWC) is a fundamental descriptor of soil water retention properties. While tension table apparatus for defining drainage curves in the near-saturated region (0 to -100 cm H20) has been available for many decades, there has been little advance in automating the process, particularly when measurements of wetting, drying are combined. We describe a new automated tension

K. Vache; J. J. McDonneIl; C. Graham; J. Ekanayake; T. Davie

215

Accepted Manuscript Liquid freshwater transport and Polar Surface Water characteristics in the East  

E-print Network

Accepted Manuscript Liquid freshwater transport and Polar Surface Water characteristics in the East this article as: Nilsson, J., Björk, G., Rudels, B., Winsor, P., Torres, D., Liquid freshwater transport to the journal pertain. #12;ACCEPTED MANUSCRIPT Liquid freshwater transport and Polar Surface Water

Nilsson, Johan

216

Statistical characteristics of a water film falling down a flat plate at different inclinations and temperatures  

Microsoft Academic Search

In this work, the statistical characteristics of the surface of a water film, freely falling down a vertical or inclined flat plate, have been investigated. The study was carried out in the frame of a research on passive cooling of heated surfaces by the evaporation of thin water films. The experiments, performed to confirm and extend previous results by the

W. Ambrosini; N. Forgione; F. Oriolo

2002-01-01

217

Characteristics of chromophoric dissolved organic matter in the nearshore waters of the western Taiwan Strait  

E-print Network

Characteristics of chromophoric dissolved organic matter in the nearshore waters of the western 2010 Keywords: CDOM absorption coefficient fluorescence remote sensing coastal waters Western Taiwan Strait a b s t r a c t Absorption and fluorescence of chromophoric dissolved organic matter (CDOM

Meyers, Steven D.

218

Characteristics of chromophoric dissolved organic matter in the nearshore waters of the western Taiwan Strait  

E-print Network

Characteristics of chromophoric dissolved organic matter in the nearshore waters of the western Keywords: CDOM absorption coefficient fluorescence remote sensing coastal waters Western Taiwan Strait a b s t r a c t Absorption and fluorescence of chromophoric dissolved organic matter (CDOM) in the nearshore

219

Electrical and Radiation Characteristics of Water in the Decimeter and Meter Range.  

National Technical Information Service (NTIS)

An examination was made of the effect of the temperature and salinity of sea water on its dielectric constants and the radiation characteristics of a smooth water surface in the 10-200 cm wavelength range. With reference to the dependence of the dielectri...

V. Y. Rayzer, Y. A. Sharkov, V. S. Etkin

1974-01-01

220

Soil water content dependent wetting front characteristics in sands T.W.J. Bautersa  

E-print Network

Soil water content dependent wetting front characteristics in sands T.W.J. Bautersa , D.A. Di. In general, this research showed that in coarse soils when an unstable wetting front occurs both the matric that the finger- like pattern in water repellent soil had many similarities with unstable wetting fronts in air

Walter, M.Todd

221

Predicting the water retention characteristic of Sicilian soils by pedotransfer functions  

Microsoft Academic Search

The accuracy in predicting the water retention characteristics of some widely used pedotransfer functions (PTFs) was tested using a database of 149 soil samples collected in three Sicilian areas. The PTFs performance was assessed in terms of maximum error (ME), average error (AE) and root mean square error (RMSE) between predicted and measured water content data. The influence of pressure

C. Antinoro; V. Bagarello; M. Castellini; A. Giangrosso; G. Giordano; M. Iovino; A. Sgroi

222

Tropine Forming Tropinone Reductase Gene from Withania somnifera (Ashwagandha): Biochemical Characteristics of the Recombinant Enzyme and Novel Physiological Overtones of Tissue-Wide Gene Expression Patterns  

PubMed Central

Withania somnifera is one of the most reputed medicinal plants of Indian systems of medicine synthesizing diverse types of secondary metabolites such as withanolides, alkaloids, withanamides etc. Present study comprises cloning and E. coli over-expression of a tropinone reductase gene (WsTR-I) from W. somnifera, and elucidation of biochemical characteristics and physiological role of tropinone reductase enzyme in tropane alkaloid biosynthesis in aerial tissues of the plant. The recombinant enzyme was demonstrated to catalyze NADPH-dependent tropinone to tropine conversion step in tropane metabolism, through TLC, GC and GC-MS-MS analyses of the reaction product. The functionally active homodimeric ?60 kDa enzyme catalyzed the reaction in reversible manner at optimum pH 6.7. Catalytic kinetics of the enzyme favoured its forward reaction (tropine formation). Comparative 3-D models of landscape of the enzyme active site contours and tropinone binding site were also developed. Tissue-wide and ontogenic stage-wise assessment of WsTR-I transcript levels revealed constitutive expression of the gene with relatively lower abundance in berries and young leaves. The tissue profiles of WsTR-I expression matched those of tropine levels. The data suggest that, in W. somnifera, aerial tissues as well possess tropane alkaloid biosynthetic competence. In vivo feeding of U-[14C]-sucrose to orphan shoot (twigs) and [14C]-chasing revealed substantial radiolabel incorporation in tropinone and tropine, confirming the de novo synthesizing ability of the aerial tissues. This inherent independent ability heralds a conceptual novelty in the backdrop of classical view that these tissues acquire the alkaloids through transportation from roots rather than synthesis. The TR-I gene expression was found to be up-regulated on exposure to signal molecules (methyl jasmonate and salicylic acid) and on mechanical injury. The enzyme's catalytic and structural properties as well as gene expression profiles are discussed with respect to their physiological overtones. PMID:24086372

Kushwaha, Amit Kumar; Sangwan, Neelam Singh; Trivedi, Prabodh Kumar; Negi, Arvind Singh; Misra, Laxminarain; Sangwan, Rajender Singh

2013-01-01

223

Evaluating the risks of unregulated and emerging chemicals found in real world mixtures of drinking water under changing source water characteristics and alternative disinfection processes  

EPA Science Inventory

This research will provide information to OW and the water community regarding the health effects of non-regulated DBPs mixtures present in drinking water. Research comparing disinfection process or source water characteristics compared to chlorination will determine if proposed ...

224

Chemical characteristics of water-soluble components in TSP over Guiyang, SW China, 2003  

Microsoft Academic Search

Total suspended particles (TSP) were collected in 2003 to study chemical characteristics of water-soluble inorganic ions (Cl?, NO3?, SO42?, NH4+, Ca2+, Mg2+) and water-soluble organic carbon (WSOC) in a karst city Guiyang, which suffers from serious acid rain problems. Concentrations of the TSP matter were 44.40–385.09?gm?3, closely associated with relative humidity (RH). Water-soluble matters of TSP are acidic in nature

Hua-Yun Xiao; Cong-Qiang Liu

2004-01-01

225

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

USGS Publications Warehouse

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.

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

1999-01-01

226

Still too hot: examination of water temperature and water heater characteristics 24 years after manufacturers adopt voluntary temperature setting.  

PubMed

Although water heater manufacturers adopted a voluntary standard in the 1980s to preset thermostats on new water heaters to 120°F, tap water scald burns cause an estimated 1500 hospital admissions and 100 deaths per year in the United States. This study reports on water temperatures in 976 urban homes and identifies water heater and household characteristics associated with having safe temperatures. The temperature of the hot water, type and size of water heater, date of manufacture, and the setting of the temperature gauge were recorded. Demographic data, including number of people living in the home and home ownership, were also recorded. Hot water temperature was unsafe in 41% of homes. Homeowners were more likely to have safer hot water temperature (<120°F) than renters (63 vs 54%; P < .01). For 11% of gas water heaters, the water temperature was >130°F, although the gauge was set at less than 75% of its maximum setting. In a multivariate logistic regression, electric water heaters were more likely to have safe hot water temperatures than gas water heaters (odds ratio R=4.99; P < .01). Water heaters with more gallons per person in the household were more likely to be at or below the recommended 120°F. Our results suggest that hot water temperatures remain dangerously high for a substantial proportion of urban homes despite the adoption of voluntary standards to preset temperature settings by manufacturers. This research highlights the need for improved prevention strategies, such as installing thermostatic mixing valves, to ensure a safer temperature. PMID:23514986

Shields, Wendy C; McDonald, Eileen; Frattaroli, Shannon; Perry, Elise C; Zhu, Jeffrey; Gielen, Andrea C

2013-01-01

227

Study of water hammer due to a sudden steam bubble collapse using the characteristics method  

SciTech Connect

The water hammer phenomenon, due to a sudden collapsing of steam in a subcooled liquid, may affect the nuclear steam supply system in several adverse ways. The cumulative effects of steam condensation water hammer in steam generator feed lines can degrade the steam generator integrity. This type of water hammer event also occurs in the surge tank of boiling water reactors. Water hammer may also play a limiting role in the reactor vessel pressure during the reflood stages of a loss-of-coolant accident. For these reasons, water hammer continues to be a major issue in the nuclear power industry. It is, therefore, very desirable to demonstrate accurate means of calculating the time-dependent pressure due to water hammer. This study presents a numerical program developed for estimating the time-dependent pressure response to steam bubble collapse. The method of characteristics (MOC) is utilized to determine pressure propagation due to water hammer.

Davis, F.J. Jr.; Hassan, Y.A.

1987-01-01

228

Post-treatment of desalinated water and water quality characteristics in Yanbu Industrial City  

Microsoft Academic Search

Yanbu Industrial City (YIC) in Saudi Arabia depends on seawater desalination for its entire fresh water supply. The fresh water is supplied by a desalination plant that consists of nine multi-stage flash (MSF) distillation units and seven reverse osmosis (RO) desalination trains. The product water from the MSF and RO desalination processes requires post-treatment to prepare it for potable use.

Ahmed S. Bajahlan; Jong-Mihn Wie

2012-01-01

229

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

Microsoft Academic Search

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

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

230

Survival and Physiological Responses of Hatchling Blanding's Turtles ( Emydoidea blandingii ) to Submergence in Normoxic and Hypoxic Water under Simulated Winter Conditions  

Microsoft Academic Search

Overwintering habits of hatchling Blanding's turtles (Emydoi- dea blandingii) are unknown. To determine whether these tur- tles are able to survive winter in aquatic habitats, we submerged hatchlings in normoxic (155 mmHg Po2) and hypoxic (6 mmHg Po2) water at 4C, recording survival times and mea- suring changes in key physiological variables. For comparison, we simultaneously studied hatchling softshell (Apalone

Stephen A. Dinkelacker; Jon P. Costanzo; John B. Iverson; Richard E. Lee Jr.

2005-01-01

231

Physiology and Survival of Atlantic Salmon following Exhaustive Exercise in Hard and Softer Water: Implications for the Catch-and-Release Sport Fishery  

Microsoft Academic Search

This study examined the influence of environmental water hardness (40 mg\\/L versus 100 mg\\/L CaCO3) on the physiology and survival of exhaustively exercised Atlantic salmon Salmo salar. Cannulated Atlantic salmon provided blood samples at rest and at 0, 1, 2, 4, and 8 h postexercise, whereas white muscle samples were acquired from noncannulated Atlantic salmon at rest and at 0

James D. Kieffer; Andrew M. Rossiter; Christine A. Kieffer; Kevin Davidson; Bruce L. Tufts

2002-01-01

232

Morphological characteristics of urban water bodies: mechanisms of change and implications for ecosystem function.  

PubMed

The size, shape, and connectivity of water bodies (lakes, ponds, and wetlands) can have important effects on ecological communities and ecosystem processes, but how these characteristics are influenced by land use and land cover change over broad spatial scales is not known. Intensive alteration of water bodies during urban development, including construction, burial, drainage, and reshaping, may select for certain morphometric characteristics and influence the types of water bodies present in cities. We used a database of over one million water bodies in 100 cities across the conterminous United States to compare the size distributions, connectivity (as intersection with surface flow lines), and shape (as measured by shoreline development factor) of water bodies in different land cover classes. Water bodies in all urban land covers were dominated by lakes and ponds, while reservoirs and wetlands comprised only a small fraction of the sample. In urban land covers, as compared to surrounding undeveloped land, water body size distributions converged on moderate sizes, shapes toward less tortuous shorelines, and the number and area of water bodies that intersected surface flow lines (i.e., streams and rivers) decreased. Potential mechanisms responsible for changing the characteristics of urban water bodies include: preferential removal, physical reshaping or addition of water bodies, and selection of locations for development. The relative contributions of each mechanism likely change as cities grow. The larger size and reduced surface connectivity of urban water bodies may affect the role of internal dynamics and sensitivity to catchment processes. More broadly, these results illustrate the complex nature of urban watersheds and highlight the need to develop a conceptual framework for urban water bodies. PMID:25154097

Steele, M K; Heffernan, J B

2014-07-01

233

Effect of ultraviolet-B radiation in laboratory on morphological and ultrastructural characteristics and physiological parameters of selected cultivar of Oryza sativa L.  

PubMed

Ultraviolet-B radiation (UVBR) affects plants in many important ways, including reduction of growth rate and primary productivity, and changes in ultrastructures. Rice (Oryza sativa) is one of the most cultivated cereals in the world, along with corn and wheat, representing over 50% of agricultural production. In this study, we examined O. sativa plants exposed to ambient outdoor radiation and laboratory-controlled photosynthetically active radiation (PAR) and PAR + UVBR conditions for 2 h/day during 30 days of cultivation. The samples were studied for morphological and ultrastructural characteristics, and physiological parameters. PAR + UVBR caused changes in the ultrastructure of leaf of O. sativa and leaf morphology (leaf index, leaf area and specific leaf area, trichomes, and papillae), plant biomass (dry and fresh weight), photosynthetic pigments, phenolic compounds, and protein content. As a photoprotective acclimation strategy against PAR + UVBR damage, an increase of 66.24% in phenolic compounds was observed. Furthermore, PAR + UVBR treatment altering the levels of chlorophylls a and b, and total chlorophyll. In addition, total carotenoid contents decreased after PAR + UVBR treatment. The results strongly suggested that PAR + UVBR negatively affects the ultrastructure, morphology, photosynthetic pigments, and growth rates of leaf of O. sativa and, in the long term, it could affect the viability of this economically important plant. PMID:23708376

de Almeida, Sérgio L; Schmidt, Éder C; Pereira, Debora Tomazi; Kreusch, Marianne; Felix, Marthiellen R de L; Osorio, Luz K P; de Paula Martins, Roberta; Latini, Alexandra; Ramlov, Fernanda; Chow, Fungyi; Maraschin, Marcelo; Rodrigues, Ana C; Bouzon, Zenilda L

2013-12-01

234

Influence of carvacrol and thymol on the physiological attributes, enterotoxin production and surface characteristics of Staphylococcus aureus strains isolated from foods  

PubMed Central

This study evaluated the influence of the phenolic compounds carvacrol (CAR) and thymol (THY) on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 ?L/mL) of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR and THY at 0.6 and 1.2 ?L/mL and increased up to 120 min of exposure. Electron microscopy of cells exposed to CAR and THY (0.6 ?L/mL) revealed that individual cells appeared to be deformed, with projections of cellular material. The observations of leakage of cellular material and an altered cell surface suggest that gross damage to a cell’s cytoplasmic membrane, which results in a disruption in protein secretion, could be responsible for the anti-staphylococcal properties of CAR and THY. PMID:24159280

Souza, E.L.; Oliveira, C.E.V.; Stamford, T.L.M.; Conceicao, M.L.; Neto, N.J. Gomes

2013-01-01

235

Molecular Characteristics of Dissociated Water with Memory Effect from Methane Hydrates  

NASA Astrophysics Data System (ADS)

The properties of sI methane hydrate dissociation at different temperatures are investigated using molecular dynamics (MD) simulations, focusing on the characteristics of structure of melting water that has memory effect. Upon melting, the clathrate structures of hydrate are damaged. The density of dissolved methane decreases as the melting temperature rises. There is a positive correlation between the density of dissociated water molecules and melting temperature. Most oxygen atoms of dissociated water molecules remain tetrahedrally coordinated whereas the hydrate-like torsion angles (H-O-O-H) are like that of normal water. Therefore, the tetrahedrally coordinated oxygen atoms are one of the factors contributing to the memory effect.

Li, Qibin; Liu, Chao; Chen, Xi

2014-02-01

236

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

PubMed

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

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

2012-10-15

237

Water cooling characteristics in an enclosed vacuum tank by water driven ejector  

Microsoft Academic Search

The general cooling tower is a device for cooling water in industrial condensers or heat exchangers. The present cooling towers\\u000a have defects with noises, complicated structures and environmental problems. This paper focuses on a new water cooling system\\u000a using the latent heat of evaporation in an enclosed vacuum tank and a water driven ejector system. Several experiments were\\u000a carried out

Hyo Min Jeong; Han Shik Chung; Kang Youl Bae; Se Hyun Kim; You Sik Shin

2005-01-01

238

The daily evaporation characteristics of deeply buried phreatic water in an extremely arid region  

NASA Astrophysics Data System (ADS)

Measurements of the daily evaporation characteristics of deeply buried phreatic water in an extremely arid area are reported. The results are used to analyze the mechanism responsible for water movement in the groundwater-soil-plant-atmosphere continuum. A closed PVC greenhouse was set up on Gobi land at the top of the Mogao Grottoes where phreatic water is more than 200 m deep. An air-conditioning unit and an automatic weighing scale were placed inside the greenhouse to condense and monitor phreatic evaporation and soil water changes in this extremely arid region. Soil temperature and humidity at various depths (0-40 cm) and other meteorological factors were also recorded on a sub-hourly basis. The relationship between evaporated water and soil water movement was analyzed by observing changes in soil weight, the condensate from the air-conditioning unit, and air moisture. The results show that phreatic water evaporation occurs from this deeply buried source in this extremely arid zone. The daily characteristics are consistent with the variation in the Sun’s radiation intensity (i.e. both show a sinusoidal behavior). In the daytime, most of the soil water does not evaporate but moves to cooler sub-layers. In the afternoon, the shallow soil layer absorbs moisture as the temperature decreases. At night, an abundance of water vapor moves upwards from the sub-layers and supplements the evaporated and downward-moving moisture of the superstratum in the daytime, but there is no evaporation. The stable, upwardly migrating vapor and film water is supported by geothermy and comes from phreatic water, the daily evaporation characteristics of which changes according to soil temperature when it reaches the ground.

Li, Hongshou; Wang, Wanfu; Liu, Benli

2014-06-01

239

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)

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.

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

1978-01-01

240

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

SciTech Connect

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.

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

1989-06-01

241

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

Microsoft Academic Search

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

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

2011-01-01

242

[Effects of regulated deficit irrigation on water consumption characteristics and water use efficiency of winter wheat].  

PubMed

With the high-yielding winter wheat cultivar Jimai 22 as test material, a field experiment was conducted in Yanzhou of Shandong to examine the effects of regulated deficit irrigation on the water consumption and water use efficiency (WUE) of the cultivar. Five treatments were installed, i.e., the soil relative moisture content at sowing, jointing, and anthesis stages being 80%, 65% and 65% (W0), 80%, 70% and 70% (W1), 80%, 80% and 80% (W2), 90%, 80% and 80% (W3), and 90%, 85% and 85% (W4), respectively. Under the condition of 228 mm precipitation in growth season, the total water consumption was higher in treatments W1 and W4 than in treatments W0, W2, and W3, and no difference was observed between treatments W1 and W4. Comparing with W4, treatment W1 decreased the water storage in 0-200 cm soil layer and the water consumption by wheat from jointing to anthesis stages, but increased the water consumption from anthesis to maturity stages. The water consumption rates at the stages from jointing to anthesis and from anthesis to maturity in treatment W4 were higher. Under regulated deficit irrigation, treatment W0 had higher WUE, but the grain yield was the lowest. The WUE in other treatments increased first, and then decreased with increasing irrigation amount. Both the water consumption and the grain yield were the highest in treatments W1 and W4, and treatment W1 had higher irrigation water use efficiency and irrigation benefit than treatment W4, being the best irrigation regime of high-yielding and water-saving in our study. PMID:20135999

Han, Zhan-Jiang; Yu, Zhen-Wen; Wang, Dong; Wang, Xi-Zhi; Xu, Zhen-Zhu

2009-11-01

243

Static Characteristics of Absorption Chiller-Heater Supplying Cold and Hot Water Simultaneously  

NASA Astrophysics Data System (ADS)

Absorption chiller-heaters which can supply both chilled water and hot water at the same time, are used for cooling and heating air conditioning systems. In this paper, we classified absorption cold and hot water generating cycles and control methods, studied these absorption cycles by cycle simulation. In economizer cycle, condensed refrigerant which heats hot water is transported to cooling cycle and used effectively for cooling chilled water, Concerning with transported condensed refrigerant, there are two methods, all condensed refrigerant or required refrigerant for cooling are transported to cooling cycle, and required refrigerant method is better for energy saving. Adding improvement of solution control to this economizer cycle, simultaneous cold and hot water supplying chiller-heaters have good characteristics of energy saving in the all region.

Inoue, Naoyuki; Irie, Tomoyoshi

244

Hysteresis and negative differential resistance of the current-voltage characteristic of a water bridge  

NASA Astrophysics Data System (ADS)

It is found experimentally that the properties of nanoporous ion-exchange membranes (hysteresis of the current-voltage characteristic in the solution and negative differential resistance), which have been discussed in recent years, are not associated with the properties of the membrane. It is shown that these effects are also observed in a floating water bridge and in water-filled tubes and are apparently determined by the geometrical shape of the liquid conductor. The observed effects are explained qualitatively.

Oshurko, V. B.; Fedorov, A. N.; Ropyanoi, A. A.; Fedosov, M. V.

2014-06-01

245

Hysteresis and negative differential resistance of the I-V characteristic of a water bridge  

NASA Astrophysics Data System (ADS)

It is experimentally demonstrated that the recently discussed properties of the nanopore ion-exchange membranes (hysteresis of the I-V characteristic in solution and negative differential resistance) are not related to the membrane structure. The same effects are observed in a water bridge and tubes filled with water and may be related to the geometrical shape of the liquid conductor. The experimental effects are qualitatively interpreted.

Oshurko, V. B.; Fedorov, A. N.; Ropyanoi, A. A.; Fedosov, M. V.

2014-08-01

246

Validation of national land?cover characteristics data for regional water?quality assessment  

Microsoft Academic Search

Land?cover information is used routinely to support the interpretation of water?quality data. The Prototype 1990 Conterminous U.S. Land Cover Characteristics Data Set, developed primarily from Advanced Very High Resolution Radiometer (AVHRR) data, was made available to the U.S. Geological Survey's National Water?Quality Assessment (NAWQA) Program. The study described in this paper explored the utility of the 1990 national data set

Ronald B. Zelt; Jesslyn F. Brown; Michael S. Kelley

1995-01-01

247

Characteristics and spatio-temporal variability of the Amazon River Basin Water Budget  

Microsoft Academic Search

The spatio-temporal variations of the water budget components in the Amazon region are investigated by using a combination of hydrometeorological observations and moisture fluxes derived from the NCEP\\/NCAR reanalyses, for the period 1970–1999. The key new finding of this study identifies the major differences in the water balance characteristics and variability between the northern and southern parts of the basin.

Jose A. Marengo

2005-01-01

248

Selected water-quality characteristics in the upper Mississippi River Basin, Royalton to Hastings, Minnesota. Water resources investigation  

SciTech Connect

In recent years, great emphasis has been placed on protection and conservation of water resources. In response to these needs, the U.S. Geological Survey established a monitoring network called NASQAN (National Stream Quality Accounting Network) in 1973. One of the objectives of NASQAN is to describe the areal variability in the quality of water in the nation's streams through analysis of data from this and other programs. With computerized statistical-analysis techniques available today, it is possible to analyze large quantities of data to aid in interpreting and in making decisions. The report has the following primary objectives: describe, on both a spatial and temporal basis, the stream-water quality throughout the study area upstream from the NASQAN site, Mississippi River at Nininger, Minnestoa; relate water-quality variability to general causes, such as selected basin characteristics, including land and water use; and assess how well water-quality data collected at Nininger represent the quality of water throughout the study area. In addressing the above objectives, the report first discusses the water quality in each subbasin, then examines the differences between subbasins, and then evaluates the representativeness of data collected at Nininger.

Have, M.R.

1991-01-01

249

Physiological Networks: towards systems physiology  

NASA Astrophysics Data System (ADS)

The human organism is an integrated network where complex physiologic systems, each with its own regulatory mechanisms, continuously interact, and where failure of one system can trigger a breakdown of the entire network. Identifying and quantifying dynamical networks of diverse systems with different types of interactions is a challenge. Here, we develop a framework to probe interactions among diverse systems, and we identify a physiologic network. We find that each physiologic state is characterized by a specific network structure, demonstrating a robust interplay between network topology and function. Across physiologic states the network undergoes topological transitions associated with fast reorganization of physiologic interactions on time scales of a few minutes, indicating high network flexibility in response to perturbations. The proposed system-wide integrative approach may facilitate new dimensions to the field of systems physiology.

Bartsch, Ronny P.; Bashan, Amir; Kantelhardt, Jan W.; Havlin, Shlomo; Ivanov, Plamen Ch.

2012-02-01

250

A physical-chemical model for the static water retention characteristic of unsaturated porous media  

NASA Astrophysics Data System (ADS)

Water retention characteristic or water retention curve (WRC) is an important constitutive feature of porous media, and also meanwhile is an indispensable requirement in hydraulic transport modelling. Previous experiments have indicated that the specific surface area of porous media has effects on the WRC. It has also been observed that a linear relationship generally exists between the air-water interface area and the water saturation within unsaturated porous media. However it seems that no detailed study on their internal linkage with the WRC has been reported yet. This paper, at first gives a review of the development of WRC modelling, then it tries to explain the water retention characteristic according to the physical and chemical behaviours of the phases involved in unsaturated porous media. Using the traditional capillary theory, the volume averaging theorem and the advances in physical chemistry of interfacial surfaces, this paper then derives out a formula which represents the water retention characteristic of porous media. This formula demonstrates the internal linkage of the WRC to the specific surface area of porosities. It also shows agreements with the experimental observations mathematically. Based on this formula, a fitting model is proposed for the static WRC of porous media. Finally, this model is tested to fit the WRC measurements of a wide range of porous materials. Comparison with other main models is presented.

Wang, Y.; Grove, S. M.; Anderson, M. G.

251

Analysis of drought characteristics for improved understanding of a water resource system  

NASA Astrophysics Data System (ADS)

Droughts are a reoccurring feature of the UK climate; recent drought events (2004-2006 and 2010-2012) have highlighted the UK's continued vulnerability to this hazard. There is a need for further understanding of extreme events, particularly from a water resource perspective. A number of drought indices are available, which can help to improve our understanding of drought characteristics such as frequency, severity and duration. However, at present little of this is applied to water resource management in the water supply sector. Improved understanding of drought characteristics using indices can inform water resource management plans and enhance future drought resilience. This study applies the standardised precipitation index (SPI) to a series of rainfall records (1962-2012) across the water supply region of a single utility provider. Key droughts within this period are analysed to develop an understanding of the meteorological characteristics that lead to, exist during and terminate drought events. The results of this analysis highlight how drought severity and duration can vary across a small-scale water supply region, indicating that the spatial coherence of drought events cannot be assumed.

Lennard, A. T.; Macdonald, N.; Hooke, J.

2014-09-01

252

Physiological Genomics  

NSDL National Science Digital Library

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.

1969-12-31

253

Rowing Physiology.  

ERIC Educational Resources Information Center

This review of the literature discusses and examines the methods used in physiological assessment of rowers, results of such assessments, and future directions emanating from research in the physiology of rowing. The first section discusses the energy demands of rowing, including the contribution of the energy system, anaerobic metabolism, and the…

Spinks, W. L.

254

Association of drinking-water source and use characteristics with urinary antimony concentrations.  

PubMed

Environmental factors, such as storage time, frequency of bottle reuse and temperature, have been shown to facilitate antimony (Sb) leaching from water- and food-packaging materials. The globally escalating consumption of water packaged in Sb-containing bottles, such as that of polyethylene terephthalate (PET), could increase human daily Sb doses. This study set out to investigate the relationship between drinking-water source, use characteristics, and urinary Sb concentrations (U-Sb) accompanied with survey responses of a healthy (n=35) Cypriot participant pool. One spot urine sample was collected during administration of questionnaire, while a second spot urine sample was collected from the same individual about 7 days later. Urinary and water Sb concentrations were measured with an inductively coupled plasma mass spectrometer. Survey responses showed that bottled water summed over various volumes and plastic types, such as polycarbonate and PET contributed to an average 61% of daily water consumption. Water sources such as tap, mobile stations (explained in a following section), and well water contributed to 24%, 14%, and 2% of an individual's daily water consumption pattern, respectively. Average daily potable water use of both bottled and tap water by individuals consisted of 65% drinking-water, while the remaining 35% was water used for preparing cold and hot beverages, such as, tea, coffee, and juices. A significant (P=0.02) association between per capita water consumption from PET bottles and urinary creatinine-unadjusted concentrations was observed, but this relationship did not remain after inclusion of covariates in a multivariate regression model. In the creatinine-adjusted regression model, only gender (female) was a significant (P<0.01) predictor of U-Sb, after adjusting for several covariates. It is proposed that consumption data collection on various water uses and sources among individuals could perhaps decrease the uncertainty associated with derivations of acceptable daily Sb intakes. PMID:23188481

Makris, Konstantinos C; Andra, Syam S; Herrick, Lisa; Christophi, Costas A; Snyder, Shane A; Hauser, Russ

2013-03-01

255

Gas Exchange Characteristics and Water Relations in Some Elite Okra Cultivars Under Water Deficit  

Microsoft Academic Search

Thirty-days-old plants of two cultivars of okra (Hibiscus esculentus L.), Sabzpari and Chinese-red, were subjected for 30 d to two water regimes (100 and 60 % field capacity). Leaf water potential and osmotic potential of both lines decreased significantly with the imposition of drought. Both the leaf pressure potential and osmotic adjustment were much lower in Chinese-red than those in

M. Ashraf; M. Arfan; M. Shahbaz; Ashfaq Ahmad; A. Jamil

2002-01-01

256

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

PubMed Central

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

Kim, H. W.; Matin, A.

2014-01-01

257

Microgravity alters the physiological characteristics of Escherichia coli O157:H7 ATCC 35150, ATCC 43889, and ATCC 43895 under different nutrient conditions.  

PubMed

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

Kim, H W; Matin, A; Rhee, M S

2014-04-01

258

Application of nmr spectroscopy to determine the thermodynamic characteristics of water bound to OX-50 nanosilica  

NASA Astrophysics Data System (ADS)

We have used low-temperature 1H NMR spectroscopy to determine the thermodynamic characteristics of water bound to OX-50 nanosilica (SBET ? 50 m2/g) in different media: aqueous, air, chloroform medium, and gaseous methane. We demonstrate the difference between the hydration parameters of silica OX-50 on going from an aqueous suspension to a hydrated powder. We present the water cluster size distributions in the studied systems, calculated from the Gibbs-Thomson equation. We found that the average water cluster size in suspension is considerably larger than the cluster sizes in hydrated powders.

Turov, V. V.; Gun'ko, V. M.; Gaishun, V. E.; Kosenok, Ya. A.; Golovan, A. P.

2010-09-01

259

Analysis of internal flow characteristics of a smooth-disk water-brake dynamometer  

NASA Technical Reports Server (NTRS)

The principal of absorbing power with an enclosed partially submerged rotating disk through the turbulent viscous shearing of water is discussed. Reference information is used to develop a flow model of the water brake. A method is then presented that uses vector diagrams to relate the effects of rotational flow, through flow, and secondary flow to power absorption. The method is used to describe the operating characteristics of an example 111-cm (43.7-in.) diameter water brake. Correlating performance parameters are developed in a dimensional analysis.

Evans, D. G.

1973-01-01

260

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

PubMed Central

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

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

2014-01-01

261

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

E-print Network

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

Paris-Sud XI, Université de

262

Water Transport Characteristics of Gas Diffusion Layer in a PEM Fuel Cell  

SciTech Connect

A presentation addressing the following: Water transport in PEM Fuel Cells - a DoE Project 1. Gas Diffusion Layer--Role and Characteristics 2. Capillary Pressure Determinations of GDL Media 3. Gas Permeability Measurements of GDL Media 4. Conclusions and Future Activities

Ashok S. Damle; J. Vernon Cole

2008-11-01

263

THE TORQUE AND WEAR CHARACTERISTICS OF WATER-LUBRICATED BALL BEARINGS  

Microsoft Academic Search

A research program evaluating the torque and wear characteristics of ; water-lubricated ball bearings as a function of certain design parameters was ; conducted. Ball-to-race conformity, contact angle, degree of alignment, and ; contact stress were the independent variables selected for this study. Size 209 ; ball bearings with Stellite 19 races, Stellite 3 balls, snd 17-4 PH stainless ;

W. H. Goldthwaite; D. W. Knoll; C. M. Allen

1957-01-01

264

Characteristics of Marine Aggregates in Shallow-water Ecosystems: Implications for Disease Ecology  

E-print Network

Characteristics of Marine Aggregates in Shallow-water Ecosystems: Implications for Disease Ecology ecology of marine diseases has increased over the past few decades as our appreciation for their impacts for their potential role in the ecology of aquatic pathogens using underwater video surveys coupled with direct

Allam, Bassem

265

The hydrodynamic characteristic of a layer of plastic bottles as elements of a water heat accumulator  

Microsoft Academic Search

A hydrodynamic model of a water heat accumulator made of plastic bottles is described. Rows of plastic bottles on lattice\\u000a shelves are regarded as stationary layers of coarse packing. The granulometric and hydrodynamic characteristics of a packing\\u000a of plastic bottles as heat-retaining elements in a solar heating system are determined.

Sh. B. Imomov; V. D. Kim

2010-01-01

266

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

E-print Network

Water mass characteristics and solar illumination influence leatherback turtle dive patterns leatherback turtle dive patterns at high latitudes. Ecosphere 5(2):19. http://dx.doi.org/10.1890/ ES13-00158.1 Abstract. Eastern Canada hosts one of the largest seasonal aggregations of leatherback turtles (Dermochelys

Taggart, Christopher

267

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

Microsoft Academic Search

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

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

2005-01-01

268

Soil and Water Science Department University of Florida CHEMICAL CHARACTERISTICS OF YARD TRASH AND DITCH CLEANING  

E-print Network

Soil and Water Science Department University of Florida CHEMICAL CHARACTERISTICS OF YARD TRASH two important solid waste issues in Florida, i.e. #10 ditch cleanings and #11 yard trash in the RFP in ditch cleaning, and substantial amounts of organic matter in yard trash, it is more cost

Ma, Lena

269

Numerical simulation and optimization on valve-induced water hammer characteristics for parallel pump feedwater system  

Microsoft Academic Search

In this study, the method of characteristic line (MOC) was adopted to evaluate the valve-induced water hammer phenomena in a parallel pumps feedwater system (PPFS) during the alternate startup process of parallel pumps. Based on closed physical and mathematical equations supplied with reasonable boundary conditions, a code was developed to compute the transient phenomena including the pressure wave vibration, local

Wenxi Tian; G. H. Su; Gaopeng Wang; Suizheng Qiu; Zejun Xiao

2008-01-01

270

Soil porosity characteristics and water movement under zero tillage in silty soils in Argentinian Pampas  

Microsoft Academic Search

The objective of this study was to identify pore characteristics (quantity, distribution, stability and orientation of pores) that condition water dynamics under continuous zero tillage (ZT) on silty soils of the Argentinian Rolling Pampas. Soil properties were analyzed under continuous chisel plough (CP) and ZT treatments from three trials with different duration and crop sequence. The following soil properties of

M. C. Sasal; A. E. Andriulo; M. A. Taboada

2006-01-01

271

Regional distribution of longevity population and chemical characteristics of natural water in Xinjiang, China.  

PubMed

Xinjiang Province, China is recognized for the longevity of its inhabitants. To study the temporal and spatial variation of longevity region and chemical characteristics of natural water of longevity region in Xinjiang, three population censuses on county-level and 51 natural water samples from Hotan Prefecture, Xinjiang were collected and analyzed. 103 natural water samples were collected from the public papers. Population statistics on county-level showed that the number of centenarians per 100,000 inhabitants (OC) in Southern Xinjiang was 7.4(year 1990), 4.9(year 2000) and 2.1 times (year 2010) more than that of Northern Xinjiang, respectively. And distribution of the longevity index (LI%), centenarity index (CI%) and number of centenarians per 10,000 over 65 year-old subjects (UC) on county-level decreased from south to north. Natural water in Northern Xinjiang was mainly fresh soft water, and it was mainly fresh hard water and brackish hard water in Southern Xinjiang. Water quality of natural water in Northern Xinjiang was superior compare to that of Southern Xinjiang, while number of centenarians 65 year-old & over per 10,000 subjects in Northern Xinjiang were less than that of Southern Xinjiang before 2010. The research indicates that keeping on drinking water with high total hardness (TH) and Mg/Ca ratio might be good for the health. PMID:24361448

Liu, Yong-Lin; Luo, Kun-Li; Lin, Xiao-Xu; Gao, Xing; Ni, Run-Xiang; Wang, Shao-Bin; Tian, Xing-Lei

2014-03-01

272

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

USGS Publications Warehouse

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.

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

2004-01-01

273

Hydrochemical characteristics of mine waters from abandoned mining sites in Serbia and their impact on surface water quality.  

PubMed

Upon completion of exploration and extraction of mineral resources, many mining sites have been abandoned without previously putting environmental protection measures in place. As a consequence, mine waters originating from such sites are discharged freely into surface water. Regional scale analyses were conducted to determine the hydrochemical characteristics of mine waters from abandoned sites featuring metal (Cu, Pb-Zn, Au, Fe, Sb, Mo, Bi, Hg) deposits, non-metallic minerals (coal, Mg, F, B) and uranium. The study included 80 mine water samples from 59 abandoned mining sites. Their cation composition was dominated by Ca2+, while the most common anions were found to be SO4(2-) and HCO3-. Strong correlations were established between the pH level and metal (Fe, Mn, Zn, Cu) concentrations in the mine waters. Hierarchical cluster analysis was applied to parameters generally indicative of pollution, such as pH, TDS, SO4(2-), Fe total, and As total. Following this approach, mine water samples were grouped into three main clusters and six subclusters, depending on their potential environmental impact. Principal component analysis was used to group together variables that share the same variance. The extracted principal components indicated that sulfide oxidation and weathering of silicate and carbonate rocks were the primary processes, while pH buffering, adsorption and ion exchange were secondary drivers of the chemical composition of the analyzed mine waters. Surface waters, which received the mine waters, were examined. Analysis showed increases of sulfate and metal concentrations and general degradation of surface water quality. PMID:23872888

Atanackovi?, Nebojša; Dragiši?, Veselin; Stojkovi?, Jana; Papi?, Petar; Zivanovi?, Vladimir

2013-11-01

274

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

275

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.

276

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

E-print Network

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...

Bhadra, Tanmoy

2012-06-07

277

Behavioral, physical, and physiological variation among litters of cloned pigs.  

E-print Network

??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,… (more)

Archer, Gregory Scott

2012-01-01

278

Effects of water restriction on reproductive physiology and affiliative behavior in an opportunistically-breeding and monogamous songbird, the zebra finch.  

PubMed

Wild zebra finches form long-term monogamous pair-bonds that are actively maintained year-round, even when not in breeding condition. These desert finches are opportunistic breeders, and breeding is highly influenced by unpredictable rainfall. Their high levels of affiliation and complex breeding patterns make zebra finches an excellent model in which to study the endocrine regulation of affiliation. Here, we compared zebra finch pairs that were provided with water ad libitum (control) or water restricted. We examined (1) reproductive physiology, (2) pair-maintenance behaviors in several contexts, and (3) circulating and brain steroid levels. In females, water restriction profoundly reduced largest ovarian follicle size, ovary size, oviduct size, and egg laying. In males, water restriction had no effect on testes size but decreased systemic testosterone levels. However, in the hypothalamus, local testosterone and estradiol levels were unaffected by water restriction in both sexes. Systemic and local levels of the androgen precursor dehydroepiandrosterone (DHEA) were also unaffected by water restriction. Lastly, in three different behavioral paradigms, we examined a variety of pair-maintenance behaviors, and none were reduced by water restriction. Taken together, these correlational data are consistent with the hypothesis that local production of sex steroids in the brain promotes the expression of pair-maintenance behaviors in non-breeding zebra finches. PMID:23274698

Prior, Nora H; Heimovics, Sarah A; Soma, Kiran K

2013-03-01

279

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

Microsoft Academic Search

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

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

1999-01-01

280

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

PubMed

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

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

2012-01-01

281

Chemical characteristics of Central Indian Basin waters during the southern summer  

NASA Astrophysics Data System (ADS)

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.

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

282

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

PubMed

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

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

2013-10-01

283

Research on the characteristics of the water quality of rainwater runoff from green roofs.  

PubMed

This paper investigates the water quality characteristics of rainwater runoff from dual-substrate-layer green roofs in Tianjin, China. The data were collected from four different assemblies and three types of simulated rains. The storm-water runoff quality was monitored from early June through late October 2012 and from July through late November 2013. The results revealed that the runoff water quality would be improved to some extent with the ageing of green roofs and that the quality retention rate better reflected the pollutant retention capacity of the green roof than the pollutant concentration in the runoff water. The investigation clearly demonstrated that green roofs also effectively reduced the chemical oxygen demand and turbidity value and neutralised acid rain to stabilise the pH of the runoff. PMID:25325545

Gong, Kena; Wu, Qing; Peng, Sen; Zhao, Xinhua; Wang, Xiaochen

2014-01-01

284

Water absorption characteristics of novel Cu/LDPE nanocomposite for use in intrauterine devices.  

PubMed

Intrauterine devices (IUDs), especially the copper-containing IUDs (Cu-IUDs), are one of the worldwide used forms for birth control, owing to their advantages of long-lasting and high efficacy, economy, safety, and reversibility. However, it is not perfect for the existing Cu-IUDs; some shortcomings related to its side effects have not been overcome yet. For this reason, a new Cu-IUDs material, the copper/low-density polyethylene (Cu/LDPE) nanocomposite, has been developed in our research team. The structure and water uptake characteristics of this new Cu-IUDs material have been investigated by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and gravimetric analysis in this paper. The results of XRD, SEM, EDS, and FT-IR show three important outcomes associated with the structure of the nanocomposite. First, the nanocomposite is hybrid of the polymer and the copper nanoparticles (nano-Cu). Second, porosities, nano-Cu aggregates, and primary alcohol (R--CH(2)--OH) are existed in the nanocomposite. Third, the nano-Cu aggregates are distributed uniformly in the polymer matrix in general. The results of Gravimetric analysis, which associated with the water uptake characteristics of the nanocomposite, exhibit that the water absorption behavior of the nanocomposite obeys the classical diffusion theory very well, the water uptake of the nanocomposite increases with the increasing of the nano-Cu loading, and that the water uptake ability of the nanocomposite with 15.0 wt % nano-Cu (50 nm in diameter) is about 150 times larger than that of the base resin and about 45 times higher than that of the Cu/LDPE microcomposite with 15.0 wt % copper microparticles (5 microm in diameter). These water uptake characteristics are mainly attributed to the structure of the Cu/LDPE composites and the size effect of the nano-Cu. PMID:16637033

Xia, Xianping; Cai, Shuizhou; Hu, Junhui; Xie, Changsheng

2006-11-01

285

A new account of Ross Sea waters: characteristics, volumetrics, and variability  

E-print Network

by the 200 - 250 m thick floating Ross Ice Shelf (Jacobs, 1989), so only deeper subsurface waters can circulate farther inshore (Budillon, et al., 2002). 3 A conspicuous characteristic of the Ross sea continental shelves is the rugged seafloor...., 1999). Relatively fresh AABW also reaches down to as deep as 3000 m at 175°W. Export of Ross Sea Bottom Water contributes to the net cooling and ventilation of the deep ocean, making the Ross Sea a key player in the Global Thermohaline Circulation...

Stover, Christina Lee

2007-09-17

286

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

NASA Astrophysics Data System (ADS)

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.

Saikia, Dip

2008-04-01

287

Criticality characteristics of mixtures of plutonium, silicon dioxide, Nevada tuff, and water  

SciTech Connect

The nuclear criticality characteristics of mixtures of plutonium, silicon dioxide, and water (Part A) or plutonium, silicon dioxide, Nevada Yucca Mountain tuff, and water (Part B) have become of interest because of the appearance of recent papers on the subject. These papers postulate that if excess weapons plutonium is vitrified into a silicate log and buried underground, a self-sustaining neutron chain reaction may develop given sufficient time and interaction with the burial medium. Moreover, given specific geologic actions resulting in postulated configurations, the referenced papers state that nuclear explosions could occur with multi-kiloton yields or yields equivalent to hundreds of tons of TNT.

Sanchez, R.; Myers, W.; Hayes, D. [and others

1997-01-01

288

Dynamic characteristics of an air-to-water heat pump under frosting\\/defrosting conditions  

Microsoft Academic Search

The dynamic characteristics of a medium air-to-water heat pump with multi-circuit evaporator controlled by the thermostatic expansion valve (TEV) under the frosting\\/defrosting conditions were investigated experimentally. The airflow maldistribution often occurs if the fin-and-tube heat exchangers in a medium heat pump are arranged in V-type or W-type position with the fan at the top. The experimental results show that the

D. Huang; Z. L. He; X. L. Yuan

2007-01-01

289

Factors affecting drying and wetting soil-water characteristic curves of sandy soils  

Microsoft Academic Search

Drying and wetting soil-water characteristic curves (SWCCs) for five sandy soils are investigated using a Tempe pressure cell and capillary rise open tube. The test data are fitted to two SWCC equations using a least-squares algorithm. The obtained fitting parameters and some hysteretic behaviour are discussed and correlated with grain-size distribution parameters. A concept of total hysteresis is proposed to

Hong Yang; Harianto Rahardjo; Eng-Choon Leong; D. G. Fredlund

2004-01-01

290

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

USGS Publications Warehouse

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)

Fisher, J.C.

1982-01-01

291

Convective heat transfer and flow characteristics of Cu-water nanofluid  

Microsoft Academic Search

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

Qiang Li; Yimin Xuan

2002-01-01

292

Separation characteristics and the state of water in ultrafiltration charged membranes modified by anionic SAS  

Microsoft Academic Search

We have investigated separation characteristics of experimental charged ultrafiltration membranes based on aromatic polyamide\\u000a PA-100(+), PA-100(?), and membrane PA-10 modified by the solutions of sodium dodecylsulfate of various concentrations. The method of differential\\u000a scanning calorimetry was used to study the state of the water in initial and modified membranes. It has been found that the\\u000a treatment of the membranes PA-100(+)

A. A. Kavitskaya; I. D. Atamanenko; A. V. Bil’dyukevich; N. A. Klimenko

2008-01-01

293

Morphological and physiological responses of rice roots and shoots to varying water regimes and soil microbial densities  

Microsoft Academic Search

To understand the responses of rice roots and shoots to non-continuously-flooded soil–water regimes together with varied levels of soil microbial density, studies were conducted evaluating three different water regimes: intermittent flooding (IF) through the vegetative stage (IF-V), IF extended into the reproductive stage (IF-R), and soil maintained with no standing water (NSW); and three levels of soil microbial density: normal,

Abha Mishra; Norman Uphoff

2012-01-01

294

Understanding down-regulation of photosynthesis under water stress: future prospects and searching for physiological tools for irrigation management  

Microsoft Academic Search

Photosynthetic down-regulation and\\/or inhibition under water stress conditions are determinants for plant growth, survival and yield in drought-prone areas. Current knowledge about the sequence of metabolic events that leads to complete inhibition of photosynthesis under severe water stress is reviewed. An analysis of published data reveals that a key regulatory role for Rubisco in photosynthesis is improbable under water stress

JAUME FLEXAS; JOSEFINA BOTA; JOSEP CIFRE; JOSE MARIANO ESCALONA; JERONI GALMES; JAVIER GULIAS; EL-KADRI LEFI; SARA FLORINDA MARTINEZ-CANELLAS; MARIA TERESA MORENO; MIQUEL RIBAS-CARBO; DIEGO RIERA; BARTOLOME SAMPOL; HIPOLITO MEDRANO

2004-01-01

295

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)

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.

Casper, A. F.

2005-05-01

296

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

297

Regulatory Physiology  

NASA Technical Reports Server (NTRS)

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.

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

298

Response of soybean rhizosphere communities to human hygiene water addition as determined by community level physiological profiling (CLPP) and terminal restriction fragment length polymorphism (TRFLP) analysis.  

PubMed

In this report, we describe an experiment conducted at Kennedy Space Center in the biomass production chamber (BPC) using soybean plants for purification and processing of human hygiene water. Specifically, we tested whether it was possible to detect changes in the root-associated bacterial assemblage of the plants and ultimately to identify the specific microorganism(s) which differed when plants were exposed to hygiene water and other hydroponic media. Plants were grown in hydroponics media corresponding to four different treatments: control (Hoagland's solution), artificial gray water (Hoagland's+surfactant), filtered gray water collected from human subjects on site, and unfiltered gray water. Differences in rhizosphere microbial populations in all experimental treatments were observed when compared to the control treatment using both community level physiological profiles (BIOLOG) and molecular fingerprinting of 16S rRNA genes by terminal restriction fragment length polymorphism analysis (TRFLP). Furthermore, screening of a clonal library of 16S rRNA genes by TRFLP yielded nearly full length SSU genes associated with the various treatments. Most 16S rRNA genes were affiliated with the Klebsiella, Pseudomonas, Variovorax, Burkholderia, Bordetella and Isosphaera groups. This molecular approach demonstrated the ability to rapidly detect and identify microorganisms unique to experimental treatments and provides a means to fingerprint microbial communities in the biosystems being developed at NASA for optimizing advanced life support operations. PMID:10689173

Kerkhof, L; Santoro, M; Garland, J

2000-03-01

299

A comparison of physiological and behavioural parameters in C57BL\\/6J mice undergoing food or water restriction regimes  

Microsoft Academic Search

Laboratory animals, when subjected to behavioural tests, are often motivationally primed by a period of prior water or food restriction. To date, it is still debatable which restriction protocol (water versus food) is more appropriate for different species. In general, a protocol is considered appropriate if animal discomfort is kept to a minimum whilst motivation for the task is maximised.

Valter Tucci; Andrea Hardy; Patrick M. Nolan

2006-01-01

300

Water use physiologies of co-occurring goldenrods ( Solidago juncea and S. canadensis ): Implications for natural distributions  

Microsoft Academic Search

Water use patterns and the seasonal progression of functional leaf area were determined for Solidago canadensis L. var. scabra and S. juncea Ait., two species of cooccurring goldenrods which differ in their competitive ability and distribution along soil moisture gradients. Field measurements of diurnal trends in stomatal conductances and leaf water potentials indicate little difference between the species. Laboratory gas

M. A. Potvin; P. A. Werner

1983-01-01

301

Soil-Water Characteristic Curves of Red Clay treated by Ionic Soil Stabilizer  

NASA Astrophysics Data System (ADS)

The relationship of red clay particle with water is an important factor to produce geological disaster and environmental damage. In order to reduce the role of adsorbed water of red clay in WuHan, Ionic Soil Stabilizer (ISS) was used to treat the red clay. Soil Moisture Equipment made in U.S.A was used to measure soil-water characteristic curve of red clay both in natural and stabilized conditions in the suction range of 0-500kPa. The SWCC results were used to interpret the red clay behavior due to stabilizer treatment. In addition, relationship were compared between the basic soil and stabilizer properties such as water content, dry density, liquid limit, plastic limit, moisture absorption rate and stabilizer dosages. The analysis showed that the particle density and specific surface area increase, the dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. After treatment with the ISS, the geological disasters caused by the adsorbed water of red clay can be effectively inhibited.

Cui, D.; Xiang, W.

2009-12-01

302

A STUDY ON VARIABILITY CHARACTERISTIC OF WATER QUALITY IN TIDAL AREA OF URBAN RIVER  

NASA Astrophysics Data System (ADS)

In order to clarify variability characteristic of water quality in tidal area of urban river, results of field observation at ordinary water (about the water quality change before and after dredging) and rainfall in the tidal area of the Nihonbashi River are reported in this paper. From the results of field observation, following results are obtained;1) The mean value of dissolved oxygen saturation of all layers decreased by 25.8% at the spring tide, by 20.4% at the neap tide before and after dredging. 2) BOD concentration decreased and T-P concentration increased after dredging. T-N concentration decreased after dredging at the low tide. 3) When total rainfall was 10.5mm in 7 hours, value of dissolved oxygen saturation did not change in all layers, and it increased by 20% after 7 days. 4) During daytime both air temperature and water temperature increased. On the other hand, during nighttime water temperature decreased in spite of air temperature increased. 5) Water velocity repeated reverse flow and uniform flow during a hour period.

Yamakado, Yasuki

303

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

PubMed Central

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

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

2013-01-01

304

Dynamic moisture sorption characteristics of xerogels from water-swellable oligo(oxyethylene) lignin derivatives.  

PubMed

Highly swellable lignin derivatives were prepared by cross-linking of oxidatively preactivated spruce organosolv lignin (OSL) with poly(ethylene) glycol diglycidyl ether (PEGDGE). The lignin gels obtained are considered to be an environmentally friendly alternative to synthetic hydrogels and superabsorbents and represent a novel type of lignin based functional materials. For their application, it is not only the absorption of water in terms of hydrogel swelling that plays an important role, but also the adsorption and retention of moisture by the corresponding xerogels. To reveal the mechanisms involved in moistening and reswelling of the lignin gels, the interaction of water vapor with lyophilized xerogels was investigated and compared with sorption characteristics of parent lignin. The chemical structure of PEGDGE-modified lignin was investigated using attenuated total reflectance Fourier-transformed infrared spectroscopy and selective aminolysis and was related to its sorption and swelling characteristics. Bound and free water in hydrogels was determined by differential scanning calorimetry and by measuring the free swelling capacity of the gels. Moisture sorption of OSL and PEGDGE-modified lignin xerogels was determined using dynamic vapor sorption analysis. In order to determine monolayer and multilayer sorption parameters, sorption data were fitted to the Brunauer-Emmett-Teller and the Guggenheim-Anderson-de Boer model. Swelling properties of the hydrogels and moisture sorption of the corresponding xerogels were found to be strongly dependent on the degree of chemical modification with PEGDGE: Total and free water content of hydrogels decrease with increasing cross-linking density; on the other hand, water bound in hydrogels and moisture sorption of xerogels at high levels of water activity strongly increase, presumably because of the hydration of hydrophilic oligo(oxyethylene) and oligo(oxyethylene) glycol substituents, which lead to moisture diffusion into the xerogel matrix, plasticization, and swelling of the gels. PMID:23075458

Passauer, Lars; Struch, Marlene; Schuldt, Stefan; Appelt, Joern; Schneider, Yvonne; Jaros, Doris; Rohm, Harald

2012-11-01

305

[Characteristics of stable isotopes in soil water under several typical land use patterns on Loess Tableland].  

PubMed

In this study, the precipitation over the Loess Tableland in Changwu County of Shaanxi Province and the soil water in 0-20 m loess profiles under different land use patterns on the Tableland were sampled, and their isotope compositions were analyzed, aimed to understand the characteristics of stable isotopes in the soil water and the mechanisms of the soil water movement. In the study area, the equation of the local meteoric water line (LMWL) was deltaD = 7.39 delta180 + 4.34 (R2 = 0.94, n = 71), and the contents of the stable isotopes in the precipitation had an obvious seasonal variation of high in winter and spring and low in summer and autumn. The contents of the stable isotopes in the soil water were fell on the underside of the LMWL, and higher than those in the precipitation from July to October, indicating that the soil water was mainly replenished by the precipitation with lower stable isotope contents in summer and autumn. In the soil profiles of different land use patterns, the stable isotope contents in soil water tended to be the same with the increasing soil depth; while under the same land use patterns, the water's stable isotope composition in shallow soil layers changed greatly with time, but changed less with increasing depth. Through the comparison of the stable isotope contents in precipitation and in soil water, it was observed that the piston flow and preferential flow on the Tableland were coexisted in the process of precipitation infiltration, and the occurrence of the preferential flow had a certain relation with land use pattern. Generally, the soil desiccation caused by the negative water balance resulted from the artificial plantations of high water consumption could reduce the probability of preferential flow occurrence, whereas the precipitation infiltration in the form of preferential flow could easily occur on the farmland or natural grassland so that the soil water in deep layers or the ground water could be replenished. PMID:22720607

Cheng, Li-Ping; Liu, Wen-Zhao

2012-03-01

306

Investigating onychophoran gas exchange and water balance as a means to inform current controversies in arthropod physiology.  

PubMed

Several controversies currently dominate the fields of arthropod metabolic rate, gas exchange and water balance, including the extent to which modulation of gas exchange reduces water loss, the origins of discontinuous gas exchange, the relationship between metabolic rate and life-history strategies, and the causes of Palaeozoic gigantism. In all of these areas, repeated calls have been made for the investigation of groups that might most inform the debates, especially of taxa in key phylogenetic positions. Here we respond to this call by investigating metabolic rate, respiratory water loss and critical oxygen partial pressure (Pc) in the onychophoran Peripatopsis capensis, a member of a group basal to the arthropods, and by synthesizing the available data on the Onychophora. The rate of carbon dioxide release (VCO2) at 20 degrees C in P. capensis is 0.043 ml CO2 h(-1), in keeping with other onychophoran species; suggesting that low metabolic rates in some arthropod groups are derived. Continuous gas exchange suggests that more complex gas exchange patterns are also derived. Total water loss in P. capensis is 57 mg H2O h(-1) at 20 degrees C, similar to modern estimates for another onychophoran species. High relative respiratory water loss rates ( approximately 34%; estimated using a regression technique) suggest that the basal condition in arthropods may be a high respiratory water loss rate. Relatively high Pc values (5-10% O2) suggest that substantial safety margins in insects are also a derived condition. Curling behaviour in P. capensis appears to be a strategy to lower energetic costs when resting, and the concomitant depression of water loss is a proximate consequence of this behaviour. PMID:18805813

Clusella-Trullas, Susana; Chown, Steven L

2008-10-01

307

Nutrient characteristics of the water masses and their seasonal variability in the eastern equatorial Indian Ocean.  

PubMed

Nutrient characteristics of four water masses in the light of their thermohaline properties are examined in the eastern Equatorial Indian Ocean during winter, spring and summer monsoon. The presence of low salinity water mass with "Surface enrichments" of inorganic nutrients was observed relative to 20 m in the mixed layer. Lowest oxygen levels of 19 microM at 3 degrees N in the euphotic zone indicate mixing of low oxygen high salinity Arabian Sea waters with the equatorial Indian Ocean. The seasonal variability of nutrients was regulated by seasonally varying physical processes like thermocline elevation, meridional and zonal transport, the equatorial undercurrent and biological processes of uptake and remineralization. Circulation of Arabian Sea high salinity waters with nitrate deficit could also be seen from low N/P ratio with a minimum of 8.9 in spring and a maximum of 13.6 in winter. This large deviation from Redfield N/P ratio indicates the presence of denitrified high salinity waters with a seasonal nitrate deficit ranging from -4.85 to 1.52 in the Eastern Equatorial Indian Ocean. PMID:20547419

Sardessai, S; Shetye, Suhas; Maya, M V; Mangala, K R; Prasanna Kumar, S

2010-01-01

308

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

NASA Technical Reports Server (NTRS)

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

1966-01-01

309

Water-like solvation thermodynamics in a spherically symmetric solvent model with two characteristic lengths  

PubMed Central

We examine by molecular dynamics simulation the solubility of small apolar solutes in a solvent whose particles interact via the Jagla potential, a spherically symmetric ramp potential with two characteristic lengths: an impenetrable hard core and a penetrable soft core. The Jagla fluid has been recently shown to possess water-like structural, dynamic, and thermodynamic anomalies. We find that the solubility exhibits a minimum with respect to temperature at fixed pressure and thereby show that the Jagla fluid also displays water-like solvation thermodynamics. We further find low-temperature swelling of a hard-sphere chain dissolved in the Jagla fluid and relate this phenomenon to cold unfolding of globular proteins. Our results are consistent with the possibility that the presence of two characteristic lengths in the Jagla potential is a key feature of water-like solvation thermodynamics. The penetrable core becomes increasingly important at low temperatures, which favors the formation of low-density, open structures in the Jagla solvent. PMID:18077365

Buldyrev, Sergey V.; Kumar, Pradeep; Debenedetti, Pablo G.; Rossky, Peter J.; Stanley, H. Eugene

2007-01-01

310

Limnological characteristics of selected lakes in the Nebraska sandhills, U.S.A., and their relation to chemical characteristics of adjacent ground water  

NASA Astrophysics Data System (ADS)

Limnological characteristics of Crane, Hackberry, Island and Roundup Lakes, and chemical characteristics of shallow ground water, within the Crescent Lake National Wildlife Refuge, western Nebraska, were determined during a preliminary investigation of the interaction between lakes and ground water in this study area between 1980 and 1984. When ice cover was absent, the lakes were well-mixed vertically, regardless of season. Depth to which 1% of surface illumination penetrated was commonly less than 1m. Variability in light penetration, as measured by Secchidisk transparency, appeared to be unrelated to changes in algal biomass, even though algal biomass, measured as chlorophyll a, varied seasonally within a two-order-of-magnitude range. Blue-green algae were the most abundant phytoplankton; this condition occurred most often when the ratio of total nitrogen to total phosphorus in the lakes' water was less than 29. Although rotifers and copepod naupli commonly were the most abundant zooplankton in the lakes, cladocerans were dominant occasionally. Either sodium or calcium was the most abundant cation, and bicarbonate was the most abundant anion, in water from water-table wells and lakes sampled during the study. The second most abundant cation in the ground water was related to the location of the sampled well within the ground-water system. The lakes were a source of dissolved organic carbon seeping to ground water. Chemical and hydrologic data indicate there is interaction between lakes and ground water in the study area.

La Baugh, James W.

1986-10-01

311

Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load  

SciTech Connect

Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of /sup 3/H/sub 2/O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the /sup 3/H/sub 2/O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc.

Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

1988-11-01

312

Physiological, biochemical and morphological indicators of osmoregulatory stress in 'California' Mozambique tilapia (Oreochromis mossambicus x O. urolepis hornorum) exposed to hypersaline water.  

PubMed

The salinity tolerance of the 'California' Mozambique tilapia (Oreochromis mossambicus x O. urolepis hornorum), a current inhabitant of the hypersaline Salton Sea in California, USA, was investigated to identify osmoregulatory stress indicators for possible use in developing a model of salinity tolerance. Seawater-acclimated (35 g l(-1)) tilapia hybrids were exposed to salinities from 35-95 g l(-1), using gradual and direct transfer protocols, and physiological (plasma osmolality, [Na+], [Cl-], oxygen consumption, drinking rate, hematocrit, mean cell hemoglobin concentration, and muscle water content), biochemical (Na+, K(+)-ATPase) and morphological (number of mature, accessory, immature and apoptotic chloride cells) indicators of osmoregulatory stress were measured. Tilapia tolerated salinities ranging from 35 g l(-1) to 65 g l(-1) with little or no change in osmoregulatory status; however, in fish exposed to 75-95 g l(-1) salinity, plasma osmolality, [Na+], [Cl-], Na+, K(+)-ATPase, and the number of apoptotic chloride cells, all showed increases. The increase in apoptotic chloride cells at salinities greater than 55 g l(-1), prior to changes in physiological and biochemical parameters, indicates that it may be the most sensitive indicator of osmoregulatory stress. Oxygen consumption decreased with salinity, indicating a reduction in activity level at high salinity. Finally, 'California' Mozambique tilapia have a salinity tolerance similar to that of pure Mozambique tilapia; however, cellular necrosis at 95 g l(-1) indicates they may be unable to withstand extreme salinities for extended periods of time. PMID:15010491

Sardella, Brian A; Matey, Victoria; Cooper, Jill; Gonzalez, Richard J; Brauner, Colin J

2004-03-01

313

Effect of surplus glucose on physiological and biochemical characteristics of sugar beet leaves in relation to the age of the leaf and the whole plant  

Microsoft Academic Search

Effect of surplus glucose on physiological and biochemical parameters of leaves of different age was investigated in sugar\\u000a beet (Beta vulgaris L., subsp. saccharifera) plants in the stages of vegetative growth (SVG). Early and late SVG were differentiated by the ratio between the weights\\u000a of roots and aboveground organs (0.10 and 0.35, respectively). The excess of Glu was produced by

N. S. Novichkova; A. K. Romanova; A. R. Ignat’ev; V. A. Mudrik; S. E. Permyakov; B. N. Ivanov

2008-01-01

314

Impact of nuclear library difference on neutronic characteristics of thorium-loaded light water reactor fuel  

SciTech Connect

Impact of nuclear library difference on neutronic characteristics of thorium-loaded light water reactor fuel is investigated through cell burnup calculations using SRAC code system. Comparison of k{sub {infinity}} and nuclide composition was made between the results obtained by JENDL-3.3, ENDF/B-VI.8 and JEFF3.0 for (U, Th)O{sub 2} fuels as well as UO{sub 2} fuels, with special interest on the burnup dependence of the neutronic characteristics. The impact of nuclear data library difference on k{sub {infinity}} of (U, Th)O{sub 2} fuels was found to be significantly large compared to that of UO{sub 2} fuels. Notable difference was also found in nuclide concentration of TRU nuclides. (authors)

Unesaki, H. [Research Reactor Inst., Kyoto Univ., Asashiro-Nishi 2, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Dept. of Socio-Environmental Energy Science, Graduate School of Energy Science, Kyoto Univ., Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Isaka, S. [Dept. of Socio-Environmental Energy Science, Graduate School of Energy Science, Kyoto Univ., Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Nakagome, Y. [Research Reactor Inst., Kyoto Univ., Asashiro-Nishi 2, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Dept. of Socio-Environmental Energy Science, Graduate School of Energy Science, Kyoto Univ., Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2006-07-01

315

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

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

Crowther, Robert G; Leicht, Anthony S; Spinks, Warwick L; Sangla, Kunwarjit; Quigley, Frank; Golledge, Jonathan

2012-01-01

316

Effects of density and water availability on the behavior, physiology, and weight loss of slaughter horses during transport  

E-print Network

The aim of this study was to determine the effects of density and provision of water on behavior, stress, and weight loss in slaughter horses during transport. A 16.2-m long, single deck, semi-trailer was divided into three compartments to create...

Iacono, Christa Marie

2007-04-25

317

Quantitative effects of a water exercise program on functional and physiological capacity in subjects with knee osteoarthritis: a pilot study  

Microsoft Academic Search

Osteoarthritis (OA) is a common and debilitating disease that often affects the knees. Patients suffer from pain and disability and have associated reductions in muscle and cardiopulmonary function. We quantitatively evaluated the effects of an 8-week water exercise program (WEP) on muscle, cardiovascular, and functional capacity on patients with knee OA. Functional capacity (walking time, Jette functional status index, habitual

N. M. Fisher; D. M. Dolan; C. Brenner; D. R. Pendergast

2004-01-01

318

Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses  

NASA Astrophysics Data System (ADS)

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.

Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

2013-12-01

319

Physiological changes in cultured Sorghum bicolor (L.) Moench cells in response to induced water stress: osmotic potential, relative water content, carbohydrates, organic acids, potassium, and amino acids  

E-print Network

UUZEZCLUUZCRL CIIEUEE IE CULTURED ~8OR ICE RICCICR IL ) MOBMCH CELLS IE RESPONSE TO INDUCED WATER STRESS OSMOTIC POTEMTZAL E RELATIVE WATER CONTENT E CARBOHYDRATES U ORGANIC ACIDS@ POTASSIUM E AED AMINO ACIDS A Thesis by RICARDO DIQUEZ... ZN RESPONSB TO IHDUCBD WATBR STRESS'- OSMOTIC POTENTIAL~ RELATIVE WATER CONTENT~ CARBOHYDRATES, ORGANIC ACIDS, POTASSIUM, AND AMINO ACIDS A Thesis by RICARDO DIQUEZ Approved as to style and content by: Roberta H. Smith (Chair of Committee...

Diquez, Ricardo

2012-06-07

320

Thermodynamic characteristics of the acid dissociation of dopamine hydrochloride in water-ethanol solutions  

NASA Astrophysics Data System (ADS)

Enthalpies of the interaction of protonated dopamine with a hydroxide ion in water-ethanol mixtures in the concentration range of 0-0.8 EtOH mole fractions are measured calorimetrically. The neutralization process of dopamine hydrochloride is shown to occur endothermally in solvents with an ethanol concentration of ?0.5 mole fractions. Standard thermodynamic characteristics (?r H ?, ?r G ?, and ?r S ?) of the first-step acid dissociation of dopamine hydrochloride in solutions are calculated with regard to the autoprotolysis enthalpy of binary solvents. It is found that dissociation enthalpies vary within 9.1-64.8 kJ/mol, depending on the water-ethanol solvent composition.

Ledenkov, S. F.; Vandyshev, V. N.; Molchanov, A. S.

2012-06-01

321

Effect of pH on the rheological and structural properties of gels of water-washed chicken-breast muscle at physiological ionic strength.  

PubMed

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

Feng, Y; Hultin, H O

2001-08-01

322

Survival and physiological responses of hatchling blanding's turtles (Emydoidea blandingii) to submergence in normoxic and hypoxic water under simulated winter conditions.  

PubMed

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

Dinkelacker, Stephen A; Costanzo, Jon P; Iverson, John B; Lee, Richard E

2005-01-01

323

Adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon.  

PubMed

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

Nam, Seung-Woo; Choi, Dae-Jin; Kim, Seung-Kyu; Her, Namguk; Zoh, Kyung-Duk

2014-04-15

324

Effects of fuel properties on the burning characteristics of collision-merged alkane/water droplets  

SciTech Connect

The combustion characteristics of freely falling droplets, individually generated by the merging of colliding alkane and water droplets, were experimentally investigated. The outcome of the collision droplets was first studied and then the subsequent burning processes such as the flame appearance, ignition and burning behaviors were recorded, through either visual observation or microphotography with the aid of stroboscopic lighting. If the merged droplets were exhibited in an insertive manner, while the water droplet inserted into the alkane droplet, these yield the burning behaviors prior to the end of flame were very much similar to that of pure alkane. The burning was ended with droplet extinction for lower-C alkane, and with either droplet ''flash vaporization'' or extinction for hexadecane. And if the merged droplets were in adhesive manner, for hexadecane with large water content, they either could not be ignited for the large merged droplets, or be ignited with a much prolonged ignition delay, followed by a soot-reducing flame and an ending of droplet extinction for the small merged droplets. ''Homogeneous'' explosion was not observed in any of the tests, and ''heterogeneous'' explosion, induced by trapped air bubbles, occasionally occurred for merged droplets with C-atom in alkane is higher than dodecane. And the sudden disappearance of droplet definitely decreased the burning time and thus enhanced the burning intensity. Besides, the fuel mass consumption rates were increased, even in the cases that having droplet extinction, because of the enlargement of the surface area due to the stuffing of water droplet. (author)

Wang, C.H.; Pan, K.L.; Huang, W.C.; Wen, H.C. [Department of Mechanical Engineering, National Taiwan University, Taipei 106 (China); Yang, J.Y. [Institute of Applied Mechanics, National Taiwan University, Taipei 106 (China); Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2008-04-15

325

Electric discharge in the water: physics of formation and radiative characteristics.  

NASA Astrophysics Data System (ADS)

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.

Anpilov, Andrei; Barkhudarov, Eduard; Kozlov, Yurii; Kossyi, Igor; Silakov, Valerii; Temchin, Savelii

2004-09-01

326

Effect of various Na/K ratios in low-salinity well water on growth performance and physiological response of Pacific white shrimp Litopenaeus vannamei  

NASA Astrophysics Data System (ADS)

To investigate the influence of sodium to potassium (Na/K) ratios on the growth performance and physiological response of the Pacific white shrimp ( Litopenaeus vananmei), various concentrations of KCl were added to low-salinity well water (salinity 4) in an 8-week culture trial. Six treatments with Na/K ratios of 60:1, 42:1, 33:1, 23:1, 17:1, and 14:1 were replicated in triplicate. The highest weight-gain rate (3 506±48)% and survival rate (89.38±0.88)% was observed in well water with Na/K ratios of 23:1 and 42:1, respectively, while the feed conversion ratio (1.02±0.01), oxygen consumption, and ammonia-N excretion rate was the lowest in the medium with a Na/K ratio of 23:1. Gill Na+-K+-ATPase activity, as an indicator of osmoregulation, peaked in the treatment where the Na/K ratio was 17:1. The total hemocyte count, respiratory burst, and immune-related enzyme activities (ALP, LSZ, PO, and SOD) of L. vananmei were affected significantly by Na/K ratios ( P<0.05). After challenged with Vibrio harveyi, the cumulative mortality of shrimp reared in a Na/K ratio of 23:1 (30±14.14)% was significantly lower than the control (75±7.07)%. In conclusion, the addition of K+ to low-salinity well water in L. vannamei cultures is feasible. Na/K ratios ranging from 23:1 to 33:1 might improve survival and growth. Immunity and disease resistance are also closely related to the Na/K ratio of the low-salinity well water. The findings may contribute to the development of more efficient K + remediation strategies for L. vananmei culture in low-salinity well water.

Liu, Hongyu; Tan, Beiping; Yang, Jinfang; Lin, Yingbo; Chi, Shuyan; Dong, Xiaohui; Yang, Qihui

2014-09-01

327

Human Physiology Department of Neurobiology, Physiology,  

E-print Network

Human Physiology Minor Department of Neurobiology, Physiology, and Behavior College of Biological Sciences (530) 752 - 0410 Human Physiology Minor Requirements: Total and Development in Human Performance EXB 116 Nutrition for Physically Active Persons EXB 117 Exercise and Aging

Wainwright, Peter C.

328

[Aviation physiology].  

PubMed

Aviation physiology should be known at least in parts by the physicians advising air travellers. Due to reducing atmospheric pressure at altitude gas volume in body cavities expands (Boyle's law). This might not be a problem during ascend since air can disappear easily through natural ways. However, air must return to body cavities during descend and a person with a cold may suffer from painful barotitis. Hypoxia is mostly due to a reduced pO2 in high altitude (Daltons's Law). This may be prevented by an aircraft cabin or supplemented oxygen. Decompression sickness is very rare in aviation but divers should comply to a dive free interval before flying. PMID:10568247

Frank, P W

1999-10-01

329

Physiological and ecological implications of coupled heat and water transport mechanisms of endotherms and tundra vegetation. Progress report  

SciTech Connect

This research seeks to extend a current quantitative general heat and mass transfer model developed for the porous insulation of endotherms to include the porous media of tundra vegetation, to test the model's predictions for endotherm heat generation requirements and water loss rates for different insulations under conditions measured in the laboratory and in the field on various inanimate objects and live endotherms, and to integrate the porous media model with microclimate models to calculate heat and mass fluxes through the low canopies of tundra vegetation and the soil. 9 refs., 6 figs.

Porter, W.P.; Stewart, W.E.

1986-01-01

330

Modeling gravity effects on water retention and gas transport characteristics in plant growth substrates  

NASA Astrophysics Data System (ADS)

Growing plants to facilitate life in outer space, for example on the International Space Station (ISS) or at planned deep-space human outposts on the Moon or Mars, has received much attention with regard to NASA’s advanced life support system research. With the objective of in situ resource utilization to conserve energy and to limit transport costs, native materials mined on Moon or Mars are of primary interest for plant growth media in a future outpost, while terrestrial porous substrates with optimal growth media characteristics will be useful for onboard plant growth during space missions. Due to limited experimental opportunities and prohibitive costs, liquid and gas behavior in porous substrates under reduced gravity conditions has been less studied and hence remains poorly understood. Based on ground-based measurements, this study examined water retention, oxygen diffusivity and air permeability characteristics of six plant growth substrates for potential applications in space, including two terrestrial analogs for lunar and Martian soils and four particulate substrates widely used in reduced gravity experiments. To simulate reduced gravity water characteristics, the predictions for ground-based measurements (1 - g) were scaled to two reduced gravity conditions, Martian gravity (0.38 - g) and lunar gravity (0.16 - g), following the observations in previous reduced gravity studies. We described the observed gas diffusivity with a recently developed model combined with a new approach that estimates the gas percolation threshold based on the pore size distribution. The model successfully captured measured data for all investigated media and demonstrated the implications of the poorly-understood shift in gas percolation threshold with improved gas percolation in reduced gravity. Finally, using a substrate-structure parameter related to the gaseous phase, we adequately described the air permeability under reduced gravity conditions.

Chamindu Deepagoda, T. K. K.; Jones, Scott B.; Tuller, Markus; de Jonge, Lis Wollesen; Kawamoto, Ken; Komatsu, Toshiko; Moldrup, Per

2014-08-01

331

Laminar heat transfer and friction factor characteristics of carbon nano tube/water nanofluids.  

PubMed

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

Rathnakumar, P; Mayilsamy, K; Suresh, S; Murugesan, P

2014-03-01

332

Interacting effects of elevated temperature and additional water on plant physiology and net ecosystem carbon fluxes in a high Arctic ecosystem  

NASA Astrophysics Data System (ADS)

Arctic ecosystems are experiencing temperature increases more strongly than the global average, and increases in precipitation are also expected amongst the climate impacts on this region in the future. These changes are expected to strongly influence plant physiology and soil biogeochemistry with subsequent implications for system carbon balance. We have investigated the effects of a long-term (10 years) increase in temperature, soil water and the combination of both on a tundra ecosystem at a field manipulation experiment in NW Greenland. Leaf gas exchange, chlorophyll fluorescence, carbon (C) and nitrogen (N) content and leaf isotopic composition, and leaf morphology were measured on Salix arctica plants in treatment and control plots in June-July 2011, and continuous measurements of net plant and soil fluxes of CO2 and water were made using automatic chambers coupled to a trace gas laser analyzer. Plants in the elevated temperature (T2) treatment had the highest photosynthetic capacity in terms of net CO2 assimilation rates and photosystem II efficiencies, and lowest rates of non-photochemical energy dissipation during photosynthesis. T2 plants also had the highest leaf N content, specific leaf area (SLA) and saturation light level of photosynthesis. It appears that warming increases soil N availability, which the plants direct towards increasing photosynthetic capacity and producing larger thinner leaves. On the other hand, the plants in the plots with both elevated temperatures and additional water (T2W) had the lowest photosystem II efficiencies and the highest rates of non-photochemical energy dissipation, due more to higher levels of constitutive energy dissipation than regulated thermal quenching. Watering, both in combination with higher temperatures and alone (W treatment), also reduced leaf SLA and leaf N relative to control plots. However, net photosynthetic rates remained similar to control plants, due in part to higher stomatal conductance (W) and lower dark respiration rates (T2W). However, net ecosystem fluxes were highest in the T2W plots due to 35% increase in leaf area. Total growing season C accumulation was 3-5 times greater, water fluxes were 1.5-2 times higher, and water use efficiency was about 3 times higher in the combined treatment than the control. Net carbon and water fluxes in the elevated temperature plots were similar to the control plots, possibly indicating that enhanced soil respiration may balance increased photosynthetic uptake. The influence of climatic change on system C budgets and ecosystem-atmosphere fluxes in the high arctic systems clearly depends on the interaction between plant strategies, soil responses and the impact of multiple climatic drivers.

Maseyk, Kadmiel; Seibt, Ulrike; Lett, Céline; Lupascu, Massimo; Czimczik, Claudia; Sullivan, Patrick; Welker, Jeff

2013-04-01

333

Programmed water-induced shape-memory of bioabsorbable poly(D,L-lactide): activation and properties in physiological temperature.  

PubMed

This study reports of the novel water-induced shape-memory of bioabsorbable poly(D,L-lactide). We have developed an orientation-based programming process that generates an ability for poly(D,L-lactide) to transform its shape at 37°C in an aqueous environment without external energy and to adapt to a predefined stress level by stress generation or relaxation. In this orientation-programming process, polymer material is deformed and oriented at an elevated temperature and subsequently cooled down while retaining its deformed shape, tension, and polymer chain entanglements. At body temperature and in an aqueous environment, the shape-memory is activated by the plasticizing effect of water molecules diffused into the polymer matrix causing an entropy-driven directed relaxation of oriented and preloaded polymer chains. This plasticizing effect is clearly seen as a decrease of the onset glass transition temperature by 10-13°C. We found that ?-irradiation used for sterilizing the orientation-programmed materials strongly affected the shape-recovery rate, but not the recovery ratio. Both non-?-irradiated and ?-irradiated sample materials showed excellent shape-recovery ratios during a ten-week test period: 94 and 97%, respectively. The orientation-programmed materials generated a predefined load in a 37°C aqueous environment when their shape-recovery was restricted, but when external tension was applied to them, they adapted to the predefined level by stress relaxation. Our results show that functionality in terms of shape-memory can be generated in bioabsorbable polymers without tailoring the polymer chain structure thus shortening the time from development of technology to its utilization in medical devices. PMID:22203516

Paakinaho, K; Heino, H; Pelto, M; Hannula, M; Törmälä, P; Kellomäki, M

2012-03-01

334

Research on water discharge characteristics of PEM fuel cells by using neutron imaging technology at the NRF, HANARO.  

PubMed

An investigation into the water discharge characteristics of proton exchange membrane (PEM) fuel cells is carried out by using a feasibility test apparatus and the Neutron Radiography Facility (NRF) at HANARO. The feasibility test apparatus was composed of a distilled water supply line, a compressed air supply line, heating systems, and single PEM fuel cells, which were a 1-parallel serpentine type with a 100 cm(2) active area. Three kinds of methods were used: compressed air supply-only; heating-only; and a combination of the methods of a compressed air supply and heating, respectively. The resultant water discharge characteristics are different according to the applied methods. The compressed air supply only is suitable for removing the water at a flow field and a heating only is suitable for water at the MEA. Therefore, in order to remove all the water at PEM fuel cells, the combination method is needed at the moment. PMID:18242098

Kim, TaeJoo; Sim, CheulMuu; Kim, MooHwan

2008-05-01

335

Concentrations and characteristics of organic carbon in surface water in Arizona: Influence of urbanization  

USGS Publications Warehouse

Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p < 0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration (p < 0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m-1(milligram DOC per liter)-1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition. (C) 2000 Elsevier Science B.V.Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p<0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration (p<0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m-1(milligram DOC per liter)-1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition.The influence of urbanization, becoming increasingly common in arid regions, on dissolved organic carbon (DOC) concentrations in surface water resources was studied. DOC concentration and composition, seasonal watershed runoff events, streamflow variations, water management practices, and urban infrastructure in several Arizona watersheds were monitored. Ephemeral sites had the highest DOC levels, and unregulated perennial sites and lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater treatment plants. Reservoir outflows and wastewater treatment plant effluent had higher and less variable DOC concentrations than inflows to reservoirs. UV absorbance values, fluorescence measurements, and other indicators suggest that urban water systems (reservoirs and wastewater treatment plants) affect temporal variability in DOC concentration and composition.

Westerhoff, P.; Anning, D.

2000-01-01

336

Characteristics of water reuse and its effects on paddy irrigation system water balance and the riceland ecosystem  

Microsoft Academic Search

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

Giveson Zulu; Masaru Toyota; Shin-ichi Misawa

1996-01-01

337

Gradients of salinity stress, environmental stability and water chemistry as a templet for defining habitat types and physiological strategies in inland salt waters  

Microsoft Academic Search

The search for pattern in the geographic occurrence of salt lake flora and fauna often reveals strong associations of specific taxa with certain types of water chemistry. Solute composition, along with salinity and habitat stability, may provide a templet shaping the distribution of many organisms inhabiting saline lakes. A review of studies demonstrating habitat associations, specific solute tolerance, and ionic

David B. Herbst

2001-01-01

338

Space Physiology within an Exercise Physiology Curriculum  

ERIC Educational Resources Information Center

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…

Carter, Jason R.; West, John B.

2013-01-01

339

Physiological and Biochemical Characteristics of the Halophilic Bacteria Vibrio parahaemolyticus and V. alginolyticus Isolated from Marine Invertebrates of Peter the Great Bay, Sea of Japan  

Microsoft Academic Search

One hundred strains of halophilic vibrios were isolated from 16 species of marine invertebrates of Peter the Great Bay. Based on their morphological and biochemical characteristics, the bacteria were identified as Vibrio parahaemolyticus and Vibrio alginolyticus. Bacterial isolates possessed virulence enzymes (DNAase, lecithinase, catalase) and were characterized by a high enterotoxigenicity. It was determined that 76% of the V. parahaemolyticus

I. A. Beleneva; E. F. Maslennikova; T. Yu. Magarlamov

2004-01-01

340

Land and water use characteristics in the vicinity of the Savannah River Site  

SciTech Connect

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.

Hamby, D.M.

1991-03-01

341

Concentrations and characteristics of organic carbon in surface water in Arizona: influence of urbanization  

NASA Astrophysics Data System (ADS)

Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants ( p<0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration ( p<0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m -1(milligram DOC per liter) -1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition.

Westerhoff, P.; Anning, D.

2000-09-01

342

Seasonal and influent characteristic effects on hydrogen sulfide generation at a water reclamation plant.  

PubMed

Correlations between sulfide generation and seasonal influent wastewater characteristics were identified based on a long-term monitoring program in summer and winter at a water reclamation plant. During summer, the emission rates of hydrogen sulfide (H2S) from the liquid treatment processes increased substantially compared to those during winter due to the increased wastewater temperature. The open tanks/clarifiers were the least significant H2S emission contributors throughout the year. For solids-handling processes, the H2S emission rates did not change during the year due to similar sludge characteristics in the different seasons. The fate of sulfide in liquid treatment processes was investigated as an alternative to estimation of H2S emissions. H2S emission from the wet well and screens was proven to be robustly associated with the wastewater temperature, flow rate, 5-day biochemical oxygen demand and total Kjeldahl nitrogen levels. However, the correlation between influent parameters and H2S emission from aerated grit chambers was not statistically significant. PMID:25353935

Zhang, Yanming; Moschandreas, Demetrios; Pagilla, Krishna

2014-10-01

343

Pore Characteristics and Water Dynamics in Nuclear Waste Repository Systems-A Neutron Study  

NASA Astrophysics Data System (ADS)

The functional relationship between pore characteristics and fluid transport behavior of geological materials at field conditions from nanometer to micrometer scale provide fundamental insights into their performance efficiency as barrier materials and their role in regulating radionuclide transport in nuclear waste repositories. The unique interactions of neutrons with matter enable probing nano- to the micro-scale structures in bulk samples and in situ studies under various environmental conditions such as humidity, high pressure and temperature. Using small-angle neutron scattering (SANS), we have studied the pore structures of a number of materials relevant to nuclear waste repository systems, such as clays and rock salt under field conditions. Our SANS measurements for smectite as function of temperature at 100 % relative humidity (RH) indicated that with increasing temperature there are changes in pore features from 1-100 nm. Further data analysis indicated that, as temperature increases from 25oC to 75oC, the d-spacing of the smectite increases from 15Å to 17Å. Besides the effect of temperature and pressure on pore characteristics of clays and rock salt, our results also show that swelling and non-swelling clays display different behavior with respect to water adsorption and moisture diffusivity (Figure 1). Our results demonstrate that SANS is particularly suited for in situ studies of pore-scale characteristics of geological materials and the factors that impact their pore features. As emergent property, nano- to micro-scale structural characterization is crucial in providing insights into pore-scale processes, which are pertinent to upscale continuum model development.

Ding, M.; Xu, H.; Hartl, M. A.; Hjelm, R. P., Jr.

2012-12-01

344

Water Purification Characteristic of the Actual Constructed Wetland with Carex dispalata in a Cold Area  

NASA Astrophysics Data System (ADS)

Carex dispalata, a native plant species applied in cold districts for water purification in constructed wetlands, has useful characteristics for landscape creation and maintenance. In this study, seasonal differences in purification ability were verified, along with comparison of frozen and non-frozen periods' performance. A wetland area was constructed using a “hydroponics method” and a “coir fiber based method”. Results show that the removal rates of BOD, SS, and Chl-a were high. On this constructed wetland reduces organic pollution, mainly phytoplankton, but the removal of nitrogen and phosphorus was insufficient. The respective mean values of influent and treated water during three years were 26.6 mg/L and 12.2 mg/L for BOD, and 27.9 mg/L and 7.5 mg/L for SS. The mean value of the BOD removal rate for the non-frozen period was 2.99 g/m2/d that for the frozen period was 1.86 g/m2/d. The removal rate followed the rise of the BOD load rate. The removal rate limits were about 4 g/m2/d during the frozen period and 15 g/m2/d during the non-frozen period. For operations, energy was unnecessary. The required working hours were about 20 h annually for all maintenance and management during operations.

Tsuji, Morio; Yamada, Kazuhiro; Hiratsuka, Akira; Tsukada, Hiroko

345

Marine Plastic Pollution in Waters around Australia: Characteristics, Concentrations, and Pathways  

PubMed Central

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

Reisser, Julia; Shaw, Jeremy; Wilcox, Chris; Hardesty, Britta Denise; Proietti, Maira; Thums, Michele; Pattiaratchi, Charitha

2013-01-01

346

Loop-Closure and Gaussian Models of Collective Structural Characteristics of Capped PEO Oligomers in Water  

E-print Network

Parallel-tempering MD results for a CH$_3$(CH$_2$-O-CH$_2$)$_m$CH$_3$ chain in water are exploited as a data-base for analysis of collective structural characteristics of the PEO globule with a goal of defining models permitting statistical thermodynamic analysis of dispersants of Corexit type. The chain structure factor, relevant to neutron scattering from a deuterated chain in neutral water, is considered specifically. The traditional continuum-Gaussian structure factor is inconsistent with the simple $k \\rightarrow \\infty$ behavior, but we consider a discrete-Gaussian model that does achieve that consistency. Shifting-and-scaling the discrete-Gaussian model helps to identify the low-$k$ to high-$k$ transition near $k \\approx 2\\pi/0.6 \\mathrm{nm}$ when an empirically matched number of Gaussian links is about one-third of the total number of effective-atom sites. This short distance-scale boundary of 0.6 nm is directly verified with the $r$-space distributions, and this distance is thus identified with a nat...

Chaudhari, M I; Paulaitis, M E

2014-01-01

347

Plane-wave Sf?S reconstruction of water surface characteristics from Lambertian reflectance data  

NASA Astrophysics Data System (ADS)

The classical shape from shading (SfS) problem of computer vision is concerned with the reconstruction of a 3D object surface from its photographic image. Essential non-uniqueness and intrinsic nonlinearity make the problem challenging. This work considers the case where the object is a water surface so that the statistical approximation by superposition of plane waves is natural. An efficient greedy algorithm involving recursive refinement of wave fronts, subject to a wave-front frequency constraint is developed. The approach is evaluated using simulated reflectance data based on a set of wind-generated wave-field images obtained from detailed wave-tank measurements. The traditional setup for the SfS problem (orthographic cameras, light sources at infinity and the Lambertian surfaces) is used. Generalization to include a specular (Phong) reflectance component is also discussed. Results indicate that key statistical characteristics of the wave field related to its stage of development (evolution) are properly recovered by the approach. Thus there may be future potential for novel photographic-based remote sensing of physical drivers (e.g. wind velocity) of local water surface patterns.

Huang, Jian; O'Sullivan, Finbarr; Jike, Linhao

2012-06-01

348

Neutron transport with the method of characteristics for 3-D full core boiling water reactor applications  

NASA Astrophysics Data System (ADS)

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 the NNR fluid mechanics and heat transfer module STAR-CD for light water reactor applications. The coupling has been accomplished via an interface program, which is responsible for mapping the STAR-CD and DeCART meshes, managing communication, and monitoring convergence. DeCART obtains the solution of the 3-D Boltzmann transport equation by performing a series of 2-D modular ray tracing-based method of characteristics problems that are coupled within the framework of 3-D coarse-mesh finite difference. The relatively complex geometry and increased axial heterogeneity found in BWRs are beyond the modeling capability of the original version of DeCART. In this work, DeCART is extended in three primary areas. First, the geometric capability is generalized by extending the modular ray tracing scheme and permitting an unstructured mesh in the global finite difference kernel. Second, numerical instabilities, which arose as a result of the severe axial heterogeneity found in BWR cores, have been resolved. Third, an advanced nodal method has been implemented to improve the accuracy of the axial flux distribution. In this semi-analytic nodal method, the analytic solution to the transverse-integrated neutron diffusion equation is obtained, where the nonhomogeneous neutron source was first approximated by a quartic polynomial. The successful completion of these three tasks has allowed the application of the coupled DeCART/STAR-CD code to practical BWR problems.

Thomas, Justin W.

349

Loop-Closure and Gaussian Models of Collective Structural Characteristics of Capped PEO Oligomers in Water  

E-print Network

Parallel-tempering MD results for a CH$_3$(CH$_2$-O-CH$_2$)$_m$CH$_3$ chain in water are exploited as a data-base for analysis of collective structural characteristics of the PEO globule with a goal of defining models permitting statistical thermodynamic analysis of dispersants of Corexit type. The chain structure factor, relevant to neutron scattering from a deuterated chain in neutral water, is considered specifically. The traditional continuum-Gaussian structure factor is inconsistent with the simple $k \\rightarrow \\infty$ behavior, but we consider a discrete-Gaussian model that does achieve that consistency. Shifting-and-scaling the discrete-Gaussian model helps to identify the low-$k$ to high-$k$ transition near $k \\approx 2\\pi/0.6 \\mathrm{nm}$ when an empirically matched number of Gaussian links is about one-third of the total number of effective-atom sites. This short distance-scale boundary of 0.6 nm is directly verified with the $r$-space distributions, and this distance is thus identified with a natural size for coarsened monomers. The probability distribution of $R_g{}^2$ is compared with the classic predictions for both Gaussian model and freely-jointed chains. $\\left\\langle R_g{}^2(j)\\right\\rangle$, the contribution of the $j$-th chain segment to $\\left\\langle R_g{}^2\\right\\rangle$, depends on contour index about as expected for Gaussian chains despite significant quantitative discrepancies which express the swelling of these chains in water. Monomers central to the chain contour occupy the center of the chain globule. The density profiles of chain segments relative to their center of mass can show distinctive density structuring for smaller chains due close proximity of central elements to the globule center. But that density structuring washes-out for longer chains where many chain elements additively contribute to the density profiles.

M. I. Chaudhari; L. R. Pratt; M. E. Paulaitis

2014-04-26

350

Experimental Investigations on the Characteristics of the Ammonia-Water Absorption Refrigerator for Low Temperature Solution Cycle  

NASA Astrophysics Data System (ADS)

This report refers to some static characteristics of the ammonia-water absorption refrigerator for low temperature refrigerating process which needs the temperature below the freezing point. Especially, the influence of evaporating temperature and cooling water temperature is clarified by the experimental investigation. In addition to this, the validity of constructed simulation model of this absorption refrigerator is mentioned. The validity of simulation model is verified by the comparison of experimental results and calculation. To examine the characteristics, we conducted the performance test using the trial product of which the standard cooling capacity is 175kW. The performance is estimated according to cooling capacity and COP. As a result, the effects of the evaporating temperature and cooling water temperature on the cooling performance are clarified by the experimental research. Furthermore, the calculation of the static characteristics predicted by the simulation model is in good agreements with the experimental results.

Takei, Toshitaka; Kimijima, Shinji; Saito, Kiyoshi; Kawai, Sunao

351

Impact of Natural Conditioners on Water Retention, Infiltration and Evaporation Characteristics of Sandy Soil  

NASA Astrophysics Data System (ADS)

Soil conditioners i.e., natural deposits and organic fertilizer are used for alleviate some of poor physical properties of sandy soils such as low water retention and inefficient water use, especially in arid and semi-arid regions such as in Saudi Arabia conditions. The present study aims to investigate the impact of clay deposits and organic fertilizer on water characteristics, cumulative infiltration and intermittent evaporation of loamy sand soil. Soil sample was collected from surface layer (0-30 cm depth) of the Agricultural Experiment and Research Station at Dierab, 40 km south west of Riyadh, Saudi Arabia. Two samples of clay deposits (CD#22 and CD#23) collected from Khyleis area, Jeddah-Madina road in addition of commercial Organic Fertilizer (OF) were used in the present study. The experiments were done during August to December 2005 in soil physics laboratory, the soil was mixed with clay deposits and organic fertilizer at rates of 0, 1, 2.5, 5.0 and 10.0% (w/w). The transparent PVC columns were packed with soil to depth of 30 cm every 5.0 cm intervals to insure a homogeneity of soil in columns. The clay deposits (CD#22 and CD#23) and Organic Fertilizer (OF) mixed with the soil were packed in the upper 0-5.0 cm of each soil column. The infiltration experiment was done using a flooding apparatus (Marriot device) with constant head of 3.0 cm over the soil surface. The cumulative infiltration and wetting front depth as a function of time were recorded. The evaporation experiment was conducted in 40 cm long transparent sectioned Lucite cylinders (5.0 cm ID). Fifty millimeters of tap water were applied weekly for three wetting/drying cycles. Cumulative evaporation against time was measured daily by weighing each soil column. The soil moisture distribution at the end of the experiment was determined gravimetrically for each 5.0 cm interval. The results indicated that the three conditioners significantly increased the water constants of mixed soil (i.e., SWC, FC, PWP and AW), but the CD#22 has a superior effect. The results clearly indicated that increasing the application rate of conditioners significantly decreased the cumulative infiltration (D). The decrease in D more pronounced at higher rates. The CD#22 was more effective in reducing the cumulative infiltration. The relationship between (D) as a function of Time (T) was done by fitting the data to the Kostiakov and Philip equations. Increasing the application rate of natural conditioners restricted the wetting front movement and need more time to reach 30 cm depth. The natural conditioners significantly reduced the cumulative evaporation throughout the 3 evaporation cycles. The reduction significantly increased with increasing the application rate, except for the higher rate (10%), which increases the cumulative evaporation under the present conditions. The improvement of soil hydro-physical properties and reduction in water infiltration and cumulative evaporation are good practices for plant growth in region limited in water such as most regions in Saudi Arabia.

Abdel-Nasser, G.; Al-Omran, A. M.; Falatah, A. M.; Sheta, A. S.; Al-Harbi, A. R.

352

Prevalence and characteristics of ESBL-producing E. coli in Dutch recreational waters influenced by wastewater treatment plants.  

PubMed

Outside health care settings, people may acquire ESBL-producing bacteria through different exposure routes, including contact with human or animal carriers or consumption of contaminated food. However, contact with faecally contaminated surface water may also represent a possible exposure route. The current study investigated the prevalence and characteristics of ESBL-producing Escherichia coli in four Dutch recreational waters and the possible role of nearby waste water treatment plants (WWTP) as contamination source. Isolates from recreational waters were compared with isolates from WWTP effluents, from surface water upstream of the WWTPs, at WWTP discharge points, and in connecting water bodies not influenced by the studied WWTPs. ESBL-producing E. coli were detected in all four recreational waters, with an average concentration of 1.3 colony forming units/100ml, and in 62% of all samples. In surface waters not influenced by the studied WWTPs, ESBL-producing E. coli were detected in similar concentrations, indicating the existence of additional ESBL-E. coli contamination sources. Isolates with identical ESBL-genes, phylogenetic background, antibiotic resistance profiles, and sequence type, were obtained from effluent and different surface water sites in the same watershed, on the same day; occasionally this included isolates from recreational waters. Recreational waters were identified as a potential exposure source of ESBL-producing E. coli. WWTPs were shown to contribute to the presence of these bacteria in surface waters, but other (yet unidentified) sources likely co-contribute. PMID:24690376

Blaak, Hetty; de Kruijf, Patrick; Hamidjaja, Raditijo A; van Hoek, Angela H A M; de Roda Husman, Ana Maria; Schets, Franciska M

2014-07-16

353

The Characteristics of Chemical Constituents of Rain Water Collected by the Sequential Constant Volumetric Sampling Method in an Urban Area  

Microsoft Academic Search

In order to unveil the chemical characteristics of rain water from 1 to 8 mm, rain water measurements were conducted in downtown Okayama for one year from March, 2004 to March 2005. Analytical parameters were pH, EC and the ion concentrations, F-, Cl-, NO2-, NO3-, SO42-, PO43-, Na+, NH4+, K+, Mg2+ and Ca2+. The mean pH and EC values of

Ken Kobayashi; Eiji Yamashita; Takatoshi Hiraki; Hiroshi Ishida

2008-01-01

354

Latent cold heat energy storage characteristics by means of direct-contact-freezing between oil droplets and cold water solution  

Microsoft Academic Search

Flow and solidification characteristics of paraffin oil droplets (tetradecane with the melting point of 5.8°C, the latent heat of fusion of 229.1 kJ\\/kg and the density of 770 kg\\/m3 at 6°C) ascending in a cold water solution are experimentally investigated. The tetradecane oil is injected from a cylindrical single hole nozzle into the cold water solution and it disperses and

Hideo Inaba; Kenji Sato

1997-01-01

355

Pioneering in gravitational physiology  

NASA Technical Reports Server (NTRS)

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.

Soffen, G. A.

1983-01-01

356

Water-quality characteristics of streams in forested and rural areas of North Carolina  

USGS Publications Warehouse

Data collected in North Carolina during 1973-78 from a statewide network of 39 rural sampling sites were used to define unpolluted or baseline stream quality. The basins were 90 to 100 percent forested and, except for the unknown effects of air pollution, were relatively unaffected by man 's activities. Five distinct geochemical zones were delineated across the State. The chemical characteristics of surface waters in each zone are similar. Mean and other statistical values for major dissolved constituents, nutrients, and minor elements in base runoff and storm runoff were determined. Twenty additional rural sites were located in basins where farming activities ranged from 15 to 55 percent of basins ' land area. Data from these 20 sites were used for comparison with data from the 39 unpolluted sites to determine the increase in constituent levels caused by man. For basins where farming activities accounted for 20 or more percent of total land use, phosphorus levels were 2 to 13 times greater than those from the forested basins and several major constituents were 2 to 3 times greater. Concentrations of minor elements were essentially the same in both developed and undeveloped basins. (Kosco-USGS)

Simmons, Clyde E.; Heath, Ralph C.

1979-01-01

357

The Characteristic of Residual Charge for Water-tree Degraded XLPE and the Measurement Method  

NASA Astrophysics Data System (ADS)

Recently the measurement of residual charge has been studying as insulation deterioration diagnosis of XLPE insulated cables. Authors have studied the measurement process and the charge characteristic. The specimens are XLPE sheets of 1mm which are degraded with water-trees. There are four processes of charge removal, charge injection, ground and charge release in the measurement. The process of charge removal was introduced to measure a little charge successfully. In the process of charge injection, it was confirmed that the relation between the applied dc voltage and the charge was examined, and the higher dc voltage was, more the charge was. In addition, it has been showed that the applied process of the dc voltage greatly influences the measured charge. In the process of ground, the grounding period is changed and the charge is measured. It has been showed that the grounding period doesn't influence the measured charge greatly. In the process of charge release, the frequency and the period of applied ac voltage were changed and the charge was measured. It has been showed that neither the frequency nor the period of ac voltage greatly influence the charge measured. In addition, the dc voltage was superimposed to ac voltage, and the charge was measured. It has been showed that the charge measured changes greatly even if the dc voltage is low. The method of the insulation deterioration measurement of cable was examined from these results, and the measurement conditions and a newer method were suggested.

Ebinuma, Yasumitsu; Masui, Noriaki

358

Measurements of water film characteristics on airfol surfaces from wind-tunnel tests with simulated heavy rain  

NASA Technical Reports Server (NTRS)

This paper discusses some of the surface water characteristics obtained during recent simulated heavy rain experiments conducted at the Langley Research Center. Water film distributions and discrete film thickness measurements on several model wings are discussed. The water film distributions on the upper surfaces are shown in photographs from cameras mounted above the models, and film thickness data are presented which were obtained using resistance sensors mounted flush with the upper and lower wing model surfaces. The paper also discusses potential sources of performance decrements indicated by the data.

Hastings, E. C., Jr.; Manuel, G. S.

1985-01-01

359

Effects of soil water deficit on gas exchange characteristics and water relations of orchard lychee (Litchi chinensis Sonn.) trees.  

PubMed

Eight-year-old lychee (Litchi chinensis Sonn.) trees, cv. 'Bengal,' growing in krasnozem soil were subjected to soil water deficit from one month before flowering until harvest by covering the ground with polyethylene sheeting and withholding irrigation. The ratio of daytime stomatal conductance of unirrigated to irrigated trees decreased 20% during the three months of increasing water deficit. Predawn leaf water potentials of irrigated trees averaged about -0.3 MPa throughout the period, whereas they declined progressively to -0.9 MPa in unirrigated trees. Minimum daytime leaf water potential in the unirrigated trees decreased from -1.0 to -1.1 MPa at the beginning of the drought period to -2.2 to -2.4 MPa after three months, and calculated whole-plant conductance did not change with decreasing availability of water. The calculated soil-root water potential declined to less than -1.0 MPa in unirrigated trees. Capacitance effects on the relationship between leaf water potential and transpiration were significant only at low transpiration rates. Although unirrigated trees reduced soil water content at 0-30 cm depths to an equivalent water potential of -1.0 MPa, fruit shedding was significantly less than in irrigated trees. Water deficit had no effect on the fresh weight of pericarp, but caused increased seed size and decreased fresh weight of flesh, resulting in fruit from unirrigated trees being 16% lower in total fresh weight per fruit than fruit from irrigated trees. PMID:14967627

Batten, D J; McConchie, C A; Lloyd, J

1994-10-01

360

Physiological basis of genetic variation in leaf photosynthesis among rice (Oryza sativa L.) introgression lines under drought and well-watered conditions  

PubMed Central

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

Yin, Xinyou

2012-01-01

361

Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas  

NASA Astrophysics Data System (ADS)

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

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

362

Water Sorption and Filler Characteristics of Composites for Use in Posterior Teeth  

Microsoft Academic Search

The purpose of this investigation was to determine the water sorption and solubility, as well as the filler composition and extent of chemical degradation in water, of eight different posterior composites. With one exception, the materials with the largest quantity of fillers had the least water sorption and solubility after three months in water at 37°C. The emission spectroscopy results

H. Øysæd; I. E. Ruyter

1986-01-01

363

Study of water hammer due to a sudden steam bubble collapse using the characteristics method  

Microsoft Academic Search

The water hammer phenomenon, due to a sudden collapsing of steam in a subcooled liquid, may affect the nuclear steam supply system in several adverse ways. The cumulative effects of steam condensation water hammer in steam generator feed lines can degrade the steam generator integrity. This type of water hammer event also occurs in the surge tank of boiling water

F. J. Jr. Davis; Y. A. Hassan

1987-01-01

364

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)

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.

Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

2014-08-01

365

Heat transfer characteristics of a two-phase closed thermosyphon using de ionized water mixed with silver nano  

NASA Astrophysics Data System (ADS)

Effect of using silver nanofluid (De Ionize water mixed with silver nano and particles less than 100 nm.) on heat transfer characteristics of a two-phase closed thermosyphon at normal operating condition was investigated in this research. The thermosyphon made by copper tube with 7.5, 11.1 and 25.4 mm ID. The filling ratios of 30, 50 and 80% by evaporator length and aspect ratios of 5, 10, and 20 (Le/ d i ) with vertical position. Pure water and DI water mixed with silver nanofluid of us as working fluid to compare. The working temperatures were 40, 50 and 60°C. It was found that, the maximum hat transfer rate of 750.81 W, with aspect ratio of 20(diameter of 25.4 mm ID) and working temperature of 60°C. The DI water mixed silver nanofluids more than approximate 70% to compare with pure water.

Paramatthanuwat, T.; Boothaisong, S.; Rittidech, S.; Booddachan, K.

2010-03-01

366

Facies characteristics and magma-water interaction of the White Trachytic Tuffs (Roccamonfina Volcano, southern Italy)  

NASA Astrophysics Data System (ADS)

The Quaternary White Trachytic Tuffs Formation from Roccamonfina Volcano (southern Italy) comprises four non-welded, trachytic, pyroclastic sequences bounded by paleosols, each of which corresponds to small- to intermediate-volume explosive eruptions from central vents. From oldest to youngest they are: White Trachytic Tuff (WTT) Cupa, WTT Aulpi, WTT S. Clemente, and WTT Galluccio. The WTT Galluccio eruption was the largest and emplaced 4km3 of magma. The internal stratigraphy of all four WTT eruptive units is a complex association of fallout, surge, and pyroclastic flow deposits. Each eruptive unit is organized into two facies associations, Facies Association A below Facies Association B. The emplacement of the two facies associations may have been separated by short time breaks allowing for limited reworking and erosion. Facies Association A consists of interbedded fallout deposits, surge deposits, and subordinate ignimbrites. This facies association involved the eruption of the most evolved trachytic magma, and pumice clasts are white and well vesiculated. The grain size coarsens upward in Facies Association A, with upward increases of dune bedform wavelengths and a decrease in the proportion of fine ash. These trends could reflect an increase in eruption column height from the onset of the eruption and possibly also in mass eruption rate. Facies Association B comprises massive ignimbrites that are progressively richer in lithic clast content. This association involved the eruption of more mafic magma, and pumice clasts are gray and poorly vesiculated. Facies Association B is interpreted to record the climax of the eruption. Phreatomagmatic deposits occur at different stratigraphic levels in the four WTT and have different facies characteristics. The deposits reflect the style and degree of magma-water interaction and the local hydrogeology. Very fine-grained, lithic-poor phreatomagmatic surge deposits found at the base of WTT Cupa and WTT Galluccio could record the interaction of the erupting magma with a lake that occupied the Roccamonfina summit depression. Renewed magma-water interaction later in the WTT Galluccio eruption is indicated by fine grained, lithic-bearing phreatomagmatic fall and surge deposits occurring at the top of Facies Association A. They could be interpreted to reflect shifts of the magma fragmentation level to highly transmissive, regional aquifers located beneath the Roccamonfina edifice, possibly heralding a caldera collapse event.

Giordano, Guido

367

Mean velocity and turbulence characteristics of water flow in the bubble dispersion region induced by plunging water jet  

Microsoft Academic Search

Water was injected vertically downward through a straight circular pipe onto a water bath contained in a cylindrical vessel. Three types of bubble dispersion patterns were observed with respect to the distance from the pipe exit to the undisturbed bath surface. When the distance was short, small bubbles were generated at the bath surface and they dispersed in the whole

M. Iguchi; K. Okita; F. Yamamoto

1998-01-01

368

Experimentally studying TV3-117 gas-turbine unit characteristics at superheated water injection into a compressor  

NASA Astrophysics Data System (ADS)

The results from experimentally studying TV3-117 gas-turbine unit (GTU) characteristics at injection of cold and superheated (metastable) water to the inlet of the GTU compressor are presented. In the latter case, the finer water atomization is obtained. The water injection makes it possible to considerably increase the unit power. At a constant temperature of the working fluid downstream of the turbine combustion chamber, water injection in an amount of 1% of the air flow rate provides an increase in the turbine power by approximately 12% and expands GTU controlling potentialities. The use of the metastable superheated water atomization enables one to more reliably implement the technology of water injection into a compressor, especially into intermediate compressor stages. However, it requires accounting for operational conditions of particular installation. Due to small water droplet residence time in the compressor flow path, even with fine water atomization, in aircraft engine derivative power turbines, about 15-20% of moisture injected have no time to completely evaporate within the compressor. When injecting cold water, this figure is from 5 to 10% larger.

Favorskii, O. N.; Alekseev, V. B.; Zalkind, V. I.; Zeigarnik, Yu. A.; Ivanov, P. P.; Marinichev, D. V.; Nizovskii, V. L.; Nizovskii, L. V.

2014-05-01

369

Geochemical characteristics of Au in the water systemfrom abandoned gold mines area  

NASA Astrophysics Data System (ADS)

The AMD (acid mine drainage) poses a threat not only to the aquatic life in mountain streams and rivers, but can also contaminate groundwater and downstream water bodies. Besides pyrite, sulfides of copper, zinc, cadmium, lead and arsenic in the drainage tunnels and tailings piles also undergo similar geochemical reactions, releasing toxic metals and more H+ into the mine drainage. The fate of gold in the AMD system is reduced and precipitated with iron oxides by oxidation-reduction reaction between ferrous/ferric iron and Au3+/Au0. The objective of this study was to investigate the influence of the transport characteristic on the distance through distribution of heavy metals and gold on the interrelation between acid mine drainage and sediments in the abandoned Gwang-yang gold mine, Korea. We conducted to confirm the chemical (chemical analysis and sequential extraction) and mineralogical property (XRD, SEM-EDS and polarization microscope) from AMD, sediments and tailing samples. The result of chemical analysis showed that Fe contents in the AMD and sediments from the upstream to the downstream ranged of 10.99 to 18.60 mg/L and 478.74 to 542.98 mg/kg, respectively. Also the contents of Au and As in the sediment were respectively ranged from 14.06 to 22.85 g/t and 0.245 to 0.612 mg/kg. In XRD analysis of the sediments, x-ray diffracted d-value belong to quartz, geothite was observed. The results of SEM-EDS analysis revealed that iron hydroxide were observed in the sediment and tailing. The result of sequential extraction for Au from the sediment showed that Au predominated in 26 to 27% of Organic matter fraction(STEP 4), and 24 to 25% of Residual fraction(STEP 5).

Cho, Kanghee; Kim, Bongju; Kim, Byungjoo; Park, Cheonyoung; Choi, Nagchoul

2013-04-01

370

[Movement characteristics of Cyanobacteria under stress of water-lifting aeration].  

PubMed

In order to study the impact of algae control mixing technology on the distribution characteristics and movement of Cyanobacteria, the floating and subsiding velocity of Cyanobacteria in Taihu Lake was measured under different conditions such as different illuminance, temperature and pressure. The Cyanobacteria showed strong propensity of floating under the illuminance from 1500 1x to 6000 1x. The Cyanobacteria particle with floating velocity of more than 0.8 cm.min-1 accounted for 58% under the illuminance of 1 500 1x. The floating velocity slowed down when the illuminance was lower than 1 500 1x or higher than 6 000 1x. In the temperature range of 8 to 25 Celsius degree, the Cyanobacteria floated and the floating velocity increased with temperature. The Cyanobacteria floated under the pressure of 0- 0. 1 MPa and the floating velocity slowed down as the pressure increased. Most Cyanobacteria were suspended in the water when the pressure reached 0. 2-0. 3 MPa and only a small part of the Cyanobacteria floated or settled. When the pressure reached 0. 4-0. 6 MPa, the Cyanobacteria notably settled and the subsiding velocity increased with the increase of pressure. The Cyanobacteria particles with subsiding velocity of more than 1.0 cm.min-1 accounted for 52.5% when the pressure was 0. 6 MPa. Gas vesicles bursted when the gas vesicles of the Cyanobacteria could not bear the external pressure. The buoyancy of the Cyanobacteria diminished until the floating force became smaller than its weight, causing the particles of the Cyanobacteria to settle. Under normal atmospheric pressure, the particle diameter was positively correlated to the floating velocity, while negatively correlated to the density. Under high pressure, the particle diameter was positively correlated to the subsiding velocity and the density. PMID:25055666

Sun, Xiu-Xiu; Cong, Hai-Bing; Gao, Zheng-Juan; Cui, Chao-Jie; Cao, Qian-Qian

2014-05-01

371

[Ecological characteristics and seasonal variation of macrobenthos near the Ningjin coastal water of Shandong, East China].  

PubMed

The coastal water off Ningjin is located at the eastern end of the Shandong Peninsula, the boundary of the Northern and Southern Yellow Sea. In this paper, the ecological characteristics and seasonal variation of macrobenthic community in this region were studied, based on the investigation data collected from the four cruises in January (winter), April (spring), July (summer), and October (autumn), 2007. A total of 243 macrobenthic species were identified, of which, 96 species were of Polychaeta, 77 were of Crustacea, 43 were of Mollusca, 13 were of Echinodermata, and the rest 14 species were of other benthic groups. The dominant species varied with seasons, but Paralacydonia paradoxa (Polychaeta) and Amphioplus japonicus (Echinodermata) were dominant throughout the four seasons. The average biomass of the macrobenthos estimated from the four cruises was 9.5 g x m(-2), with the highest biomass during the spring cruise and the lowest one during the winter cruise. The average abundance estimated from the four cruises was 219.6 ind x m(-2), with the highest abundance during the winter cruise and the lowest one during the autumn cruise. The Shannon index (H) of the macrobenthos community varied from 2.82 to 3.23, the species richness index (D) varied from 2.28 to 2.75, and the species evenness index (J) varied from 0.82 to 0.86. The Bray-Curtis similarity cluster analysis and MDS ordination analyses indicated that there was a distinct distribution of macrobenthic communities from seashore to offshore, which was closely correlated with the spatial structure of bathymetry and the sediment type in the study region. PMID:23431800

Gan, Zhi-Bin; Li, Xin-Zheng; Wang, Hong-Fa; Zhang, Bao-Lin

2012-11-01

372

Effect of Cropping History on Water Retention Characteristics of Clayey Paddy Soil under Low Water Potential Conditions  

NASA Astrophysics Data System (ADS)

The water content and water potential of soil samples from paddy fields with varied cropping histories were measured under low water potential conditions. The relationships between the water content and the water potential were fitted to power equations. Analyses of the results for the fresh soils showed that the coefficient a (the water content at water potential of -1MPa) (CA) and the absolute value of the exponential index b (AB) of the fitted power equation was smaller in the soils under the cultivation of upland crops than the wetland rice. On the other hand, the difference in CA and AB for air-dried soil was not revealed between the soils under the upland crop cultivation and the soils under the wetland rice cultivation. The difference in CA for the fresh soil and for the air-dried soil and the difference in AB for the fresh soil and for air-dried soil were found to increase with continuous cropping of wetland rice, and decrease in response to continuous cropping of upland crops. These finding suggest these indices can presume cropping histories of rotational paddy fields.

Adachi, Kazuhide; Yoshida, Shuichiro; Ohno, Satoshi; Obara, Hiroshi

373

Fractals in physiology and medicine  

NASA Technical Reports Server (NTRS)

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.

Goldberger, Ary L.; West, Bruce J.

1987-01-01

374

Physiology Of Prolonged Bed Rest  

NASA Technical Reports Server (NTRS)

Report describes physiological effects of prolonged bed rest. Rest for periods of 24 hours or longer deconditions body to some extent; healing proceeds simultaneously with deconditioning. Report provides details on shifts in fluid electrolytes and loss of lean body mass, which comprises everything in body besides fat - that is, water, muscle, and bone. Based on published research.

Greenleaf, John E.

1991-01-01

375

Physiological constraints in shrimp cultures  

Microsoft Academic Search

The biological requirements of animals change considerably during development from the egg to the (early) adult stage. Some basic physiological requirements (respiration, excretion of metabolic end products, space requisites, aspects of feeding biology) of cultured animals are considered in relation to design (surface area, depth) and maintenance (water refreshment) of shrimp (and fish) culture units. From general relations between respiration

Dirk H. Spaargaren

1997-01-01

376

Physiological Adaptation in Desert Birds  

NSDL National Science Digital Library

This peer-reviewed article from BioScience journal is about adaptations desert birds. We call into question the idea that birds have not evolved unique physiological adaptations to desert environments. The rate at which desert larks metabolize energy is lower than in mesic species within the same family, and this lower rate of living translates into a lower overall energy requirement in the wild. We argue that selection has reduced oxygen consumption at the tissue level under basal conditions for birds living in deserts. We document that total evaporative water loss--the sum of cutaneous water loss (CWL) and respiratory water loss--is reduced in desert birds, and present evidence that changes in CWL are responsible for this pattern. The diminution in CWL is attributable to changes in the lipid structure of the stratum corneum of the skin, the physical barrier to diffusion of water vapor. Finally, we show linkages between physiology and life-history attributes of larks along an aridity gradient; birds from deserts have not only a reduced rate of metabolism but also a small clutch size and slow nestling development. Hence, attributes of physiology are correlated with traits that directly affect reproductive success. Our hope is that we will prompt students to question the notion that birds do not possess physiological adaptations to the desert environment, and raise the specter of doubt about "preadaptation" in birds living in deserts.

JOSEPH B. WILLIAMS and B. IRENE TIELEMAN (;)

2005-05-01

377

Characteristics of the water vapour transport over the Mackenzie river basin during the 1994\\/95 water year  

Microsoft Academic Search

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

Jinliang Liu; Ronald E. Stewart

2002-01-01

378

Effect of genotype and graft type on the hydraulic characteristics and water relations of grafted melon  

Microsoft Academic Search

From the measurements of the profiles of hydraulic conductance and water potential from soil through to the leaf system in fully established melon plants, the limits to water flow set by coupling of hydraulic conductance (k) with water relation parameters was evaluated in the laboratory using high pressure flow device (HPFM) and evaporative flux method (EF). The rootstock Arava was

Samuel Agele; Shabtai Cohen

2009-01-01

379

Cooling characteristics of hot oil pool by water mist during fire suppression  

Microsoft Academic Search

Generally water is not favored for use in suppressing hot liquid fuel fires due to concerns of vapor explosion and boil-over, which could present potential danger to nearby personnel or firefighters. This paper reports on a series of full-scale fire experiments in which water mist was used in extinguishing large hot cooking oil fires. It was shown that water mist

Zhigang Liu; Don Carpenter; Andrew K. Kim

2008-01-01

380

Cyanotoxins: characteristics, production and degradation routes in drinking water treatment with reference to the situation in Serbia.  

PubMed

Cyanobacteria are members of phytoplankton of the surface freshwaters. The accelerated eutrophication of freshwaters, especially reservoirs for drinking water, by human activity has increased the occurrence and intensity of cyanobacterial blooms. They are of concern due to their ability to produce taste and odors compounds, a wide range of toxins, which have a hepatotoxic, neurotoxic, cytotoxic and dermatotoxic behavior, being dangerous to animal and human health. Therefore, the removal of cyanobacteria, without cell lysis, and releasing of intracellular metabolites, would significantly reduce the concentration of these metabolites in the finished drinking water, as a specific aim of the water treatment processes. This review summarizes the existing data on characteristics of the cyanotoxins, their productions in environment and effective treatment processes to remove these toxins from drinking water. PMID:23391374

Panteli?, Dijana; Svir?ev, Zorica; Simeunovi?, Jelica; Vidovi?, Milka; Trajkovi?, Ivana

2013-04-01

381

Gasification characteristics of an activated carbon catalyst during the decomposition of hazardous waste materials in supercritical water  

SciTech Connect

Recently, carbonaceous materials were proved to be effective catalysts for hazardous waste decomposition in supercritical water. Gasification of the carbonaceous catalyst itself is also expected, however, under supercritical conditions. Thus, it is essential to determine the gasification rate of the carbonaceous materials during this process to determine the active lifetime of the catalysts. For this purpose, the gasification characteristics of granular coconut shell activated carbon in supercritical water alone (600-650{degrees}C, 25.5-34.5 MPa) were investigated. The gasification rate at subatmospheric pressure agreed well with the gasification rate at supercritical conditions, indicating the same reaction mechanism. Methane generation under these conditions is via pyrolysis, and thus is not affected by the water pressure. An iodine number increase of 25% was observed as a result of the supercritical water gasification.

Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr. [Univ. of Hawaii at Manoa, Honolulu, HI (United States)

1996-10-01

382

Determining the water status of Satsuma mandarin trees [ Citrus Unshiu Marcovitch] using spectral indices and by combining hyperspectral and physiological data  

Microsoft Academic Search

This study investigated the water relations of Satsuma mandarin trees [Citrus Unshiu Marcovitch] and drought stress indicators used for irrigation scheduling in orchards namely: (1) the midday leaf water potential (MLWP), (2) midday stem (or xylem) water potential (MSWP), (3) predawn leaf water potential and (4) the leaf water content. Remote sensing spectral indices were applied to predict these indicators

S. Dzikiti; J. S. Verreynne; J. Stuckens; A. Strever; W. W. Verstraeten; R. Swennen; P. Coppin

2010-01-01

383

Teaching Stress Physiology Using Zebrafish ("Danio Rerio")  

ERIC Educational Resources Information Center

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…

Cooper, Michael; Dhawale, Shree; Mustafa, Ahmed

2009-01-01

384

Theoretical Study on Dynamic Characteristics of Energy Efficiency Standard Value of Ground Water Heat Pump Air-conditioning System  

NASA Astrophysics Data System (ADS)

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.

Peng, Yi; Wang, Zhiwei; Zhang, Zhonghe; Cao, Wei; Li, Peng

385

Spatial variation in density, mean size and physiological condition of the holarctic amphipod Diporeia spp. in Lake Michigan  

Microsoft Academic Search

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

Thomas F. Nalepa; David J. Hartson; Jennifer Buchanan; Joann F. Cavaletto; Gregory A. Lang; Stephen J. Lozano

2000-01-01

386

SPATIAL VARIATION IN DENSITY, MEAN SIZE, AND PHYSIOLOGICAL CONDITION OF THE HOLARCTIC AMPHIPOD DIPOREIA SPP. IN LAKE MICHIGAN  

EPA Science Inventory

We examined spatial patterns in population characteristics and physiological condition 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 maj...

387

Effects of light radiation intensity on photosynthetic characteristics and water use efficiency of Platycladus orientalis and Pinus tabulaeformis seedlings  

Microsoft Academic Search

In order to offer a scientific basis for cultivation and management of forests, effects of light radiation intensity on photosynthetic\\u000a characteristics and water use efficiency of Platycladus orientalis and Pinus tabulaeformis were studied under different soil moisture contents. By adopting artificial control methods to soil moisture, and under simulated\\u000a photosynthetic radiation (SPR), the net photosynthetic rate (P\\u000a N), transpiration rate

Weiqiang Zhang; Kangning He; Yunqi Wang; Baitian Wang; Juntao Deng; Yi Zhou; Xijun Zhong; Zhaoqing Li

2007-01-01

388

Determination of the Hydraulic Characteristics of a Continuous-Caster Mold with a Loop-Type Water Supply System  

Microsoft Academic Search

The design and heat-engineering characteristics of continuous-caster molds determine the degree to which the chosen casting technology will be successful. Molds with a loop-type cooling system (with direct and countercurrent water flows) have come into wide use for casting large slabs. Such systems make it possible to roughly halve the consumption of coolant while maintaining the required flow velocity. Little

Yu. A. Kalyagin; S. V. Lukin; S. Yu. Yakunichev; A. A. Zaitsev

2003-01-01

389

Heat transfer characteristics of a two-phase closed thermosyphon using de ionized water mixed with silver nano  

Microsoft Academic Search

Effect of using silver nanofluid (De Ionize water mixed with silver nano and particles less than 100 nm.) on heat transfer\\u000a characteristics of a two-phase closed thermosyphon at normal operating condition was investigated in this research. The thermosyphon\\u000a made by copper tube with 7.5, 11.1 and 25.4 mm ID. The filling ratios of 30, 50 and 80% by evaporator length and aspect

T. Paramatthanuwat; S. Boothaisong; S. Rittidech; K. Booddachan

2010-01-01

390

Water sorption characteristics of light-cured dental resins and composites based on Bis-EMA\\/PCDMA  

Microsoft Academic Search

The water uptake characteristics of resins and composites based on an ethoxylated bisphenol A glycol dimethacrylate (Bis-EMA) and a polycarbonate dimethacrylate (PCDMA) were studied in detail. Polydimethacrylate resins were prepared by photopolymerization of the neat monomers and mixtures of them with various weight ratios, using the camphoroquinone\\/N,N-dimethylaminoethyl methacrylate system as initiator, while the composites were prepared from the light-curing of

Irini Sideridou; Dimitris S. Achilias; Chrysa Spyroudi; Maria Karabela

2004-01-01

391

Pervaporation characteristics of cross-linked poly(dimethylsiloxane) membranes for removal of various volatile organic compounds from water  

Microsoft Academic Search

The permeation and separation characteristics of volatile organic compounds (VOCs), such as chloroform, benzene, and toluene, from water by pervaporation through cross-linked poly(dimethylsiloxane) membranes prepared from poly(dimethylsiloxane) dimethylmethacrylate macromonomer (PDMSDMMA) and divinyl compounds, such as ethylene glycol dimethylmethacrylate (EGDM), divinyl benzene (DVB), divinyl siloxane (DVS), and divinyl perfluoro-n-hexane (DVF) are described. When aqueous solutions containing 0.05wt.% VOCs were permeated through

Tadahiro Ohshima; Yoshihisa Kogami; Takashi Miyata; Tadashi Uragami

2005-01-01

392

Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve  

Microsoft Academic Search

For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control\\u000a method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause\\u000a extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study,\\u000a the servo valve-type water

Sung-Hwan Park

2009-01-01

393

Experimental investigation on the characteristics of flash evaporation from superheated water jets for desalination  

Microsoft Academic Search

A promising method of desalination suitable for low-populated islands and remote areas is experimentally investigated at a small desalination plant capable of producing 15.2tons of fresh water per day based on the flash evaporation from superheated water jets. In this method, water at a temperature ranging from 24 to 40°C is brought to superheat condition through the injection into a

Sami Mutair; Yasuyuki Ikegami

2010-01-01

394

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...

395

A high resolution ocean model of restriction of the Mediterranean-Atlantic connection: Changes in Mediterranean circulation and water characteristics  

NASA Astrophysics Data System (ADS)

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 on 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 less 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, on the other hand, 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 explained by simplifications in the surface forcing and a different bathymetry than 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.

Topper, Robin; Meijer, Paul

2014-05-01

396

The effect of reducing the surface tension of water upon certain physical characteristics of soils  

E-print Network

to the apparent destructive effects of water upon the soil's physical condition this preliminary comparative study of addition VS no~diticn of a surface tension depressant to water was attempted, although ths evidence could not be held to be mnclusive~ because... to the apparent destructive effects of water upon the soil's physical condition this preliminary comparative study of addition VS no~diticn of a surface tension depressant to water was attempted, although ths evidence could not be held to be mnclusive~ because...

Kadry, Louay T

2012-06-07

397

Hydrogeology and Physical Characteristics of Water Samples at the Red River Aluminum Site, Stamps, Arkansas  

NASA Astrophysics Data System (ADS)

The Red River Aluminum site near Stamps, Arkansas, contains waste piles of salt cake and metal byproducts from the smelting of aluminum. The waste piles are subjected to about 50 inches of rainfall a year, resulting in the dissolution of the salts and metal. To assess the potential threat to underlying ground-water resources at the site, its hydrogeology was characterized by measuring water levels and field parameters of water quality in 23 wells and at 2 surface-water sites. Seventeen of these monitor wells were constructed at various depths for this study to allow for the separate characterization of the shallow and deep ground-water systems, the calculation of vertical gradients, and the collection of water samples at different depths within the flow system. Lithologic descriptions from drill-hole cuttings and geophysical logs indicate the presence of interbedded sands, gravels, silts, and clays to depths of 65 feet. The regionally important Sparta aquifer underlies the site. Water levels in shallow wells indicate radial flow away from the salt-cake pile located near the center of the site. Flow in the deep system is to the west and southwest toward Bodcau Creek. Water-level data from eight piezometer nests indicate a downward hydraulic gradient from the shallow to deep systems across the site. Values of specific conductance (an indicator of dissolved salts) ranged from 215 to 196,200 microsiemens per centimeter and indicate that saline waters are being transported horizontally and vertically downward away from the site.

Czarnecki, J. B.; Stanton, G. P.; Freiwald, D. A.

2001-12-01

398

Detecting the dynamic linkage between landscape characteristics and water quality in a subtropical coastal watershed, Southeast China.  

PubMed

Geospatial analysis and statistical analysis are coupled in this study to determine the dynamic linkage between landscape characteristics and water quality for the years 1996, 2002, and 2007 in a subtropical coastal watershed of Southeast China. The landscape characteristics include Percent of Built (%BL), Percent of Agriculture, Percent of Natural, Patch Density and Shannon's Diversity Index (SHDI), with water quality expressed in terms of COD(Mn) and NH(4)(+)-N. The %BL was consistently positively correlated with NH(4)(+)-N and COD(Mn) at time three points. SHDI is significantly positively correlated with COD(Mn) in 2002. The relationship between NH(4)(+)-N, COD(Mn) and landscape variables in the wet precipitation year 2007 is stronger, with R(2) = 0.892, than that in the dry precipitation years 1996 and 2002, which had R(2) values of 0.712 and 0.455, respectively. Two empirical regression models constructed in this study proved more suitable for predicting COD(Mn) than for predicting NH(4)(+)-N concentration in the unmonitored watersheds that do not have wastewater treatment plants. The calibrated regression equations have a better predictive ability over space within the wet precipitation year of 2007 than over time during the dry precipitation years from 1996 to 2002. Results show clearly that climatic variability influences the linkage of water quality-landscape characteristics and the fit of empirical regression models. PMID:22120882

Huang, Jinliang; Li, Qingsheng; Pontius, Robert Gilmore; Klemas, Victor; Hong, Huasheng

2013-01-01

399

Physiological characteristics of cold acclimatization in man  

Microsoft Academic Search

Studies were conducted on 15 healthy young soldiers to evaluate the effect of a cold acclimatization schedule on the thermoregulatory and metabolic activity on exposure to acute cold stress. These men were exposed to cold (10‡C) for 4 h daily wearing only shorts for 21 days, in a cold chamber. They were subjected to a standard cold test at 10

Lazar Mathew; S. S. Purkayastha; A. Jayashankar; H. S. Nayar

1981-01-01

400

Physiological characteristics of cold acclimatization in man  

NASA Astrophysics Data System (ADS)

Studies were conducted on 15 healthy young soldiers to evaluate the effect of a cold acclimatization schedule on the thermoregulatory and metabolic activity on exposure to acute cold stress. These men were exposed to cold (10‡C) for 4 h daily wearing only shorts for 21 days, in a cold chamber. They were subjected to a standard cold test at 10 ± 1‡C the day 1, 6, 11 and 21. The subjects were made to relax in a thermoneutral room (26 28‡C) for 1 h and their heart rate, blood pressure, oxygen consumption, oral temperature, mean skin temperature, mean body temperature, peripheral temperatures, and shivering activity were recorded. Then they were exposed to 10‡C and measurements were repeated at 30 min intervals, for 2 h. The cold induced vasodilatation (CIVD), cold pressor response and thermoregulatory efficiency tests were measured initially and at the end of acclimatization schedule. The data show that the procedure resulted in elevated resting metabolism, less fall in body temperature during acute cold stress, reduction in shivering, improvement in CIVD and thermoregulatory efficiency and less rise in BP and HR during cold pressor response. The data suggest the possibility of cold acclimatization in man by repeated exposure to moderately severe cold stress.

Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Nayar, H. S.

1981-09-01

401

Space physiology within an exercise physiology curriculum.  

PubMed

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 chronic terrestrial exercise (TEx) and microgravity (?G). We used a series of peer-reviewed publications to demonstrate that many of the physiological adaptations to TEx and ?G are opposite. For example, TEx typically improves cardiovascular function and orthostatic tolerance, whereas ?G can lead to declines in both. TEx leads to muscle hypertrophy, and ?G elicits muscle atrophy. TEx increases bone mineral density and red blood cell mass, whereas ?G decreases bone mineral density and red blood cell mass. Importantly, exercise during spaceflight remains a crucial countermeasure to limit some of these adverse physiological adaptations to ?G. This curriculum develops critical thinking skills by dissecting peer-reviewed articles and discussing the strengths and weaknesses associated with simulated and actual ?G studies. Moreover, the curriculum includes studies on both animals and humans, providing a strong translational component to the curriculum. In summary, we have developed a novel space physiology curriculum delivered during the final weeks of an exercise physiology course in which students gain critical new knowledge that reinforces key concepts presented throughout the semester. PMID:24022767

Carter, Jason R; West, John B

2013-09-01

402

Impact of acute water and feed deprivation events on growth performance, intestinal characteristics, and serum stress markers in weaned pigs.  

PubMed

The impact of acute stressors (24-h feed or water deprivation) on growth performance, intestinal characteristics, and serum stress markers in weaned pigs was evaluated. Pigs (6.21 ± 0.29 kg) were allotted in a randomized complete block design to 4 treatments on the basis of BW at the time of weaning. There were 8 mixed-sex pigs in each of 12 pens per treatment. Treatments were arranged as a 2 × 2 factorial and consisted of a feed or water stressor that included a 0- or 24-h deprivation period postweaning, and pigs were subsequently allowed access to feed and water. Growth performance was measured 1, 7, 14, and 28 d postweaning. Serum and intestinal samples were taken 1 and 7 d postweaning. Serum was analyzed for cortisol and corticotrophin-releasing factor, and villus height, crypt depth, and mast cell density were measured in the jejunum and the ileum. Expression of mucin (MUC2), tumor necrosis factor ? (TNF-?), interleukin 6 (IL-6), claudin 1 (CL-1), occludin (OC), and zonula occludens 1 (ZO-1) genes were measured on d 1 and 7 postweaning in the jejunum and ileum by real-time PCR. There was a decrease (P < 0.05) in ADG with the water stressor 1 d postweaning, although subsequently, there were improvements (P < 0.05) in ADG and feed efficiency. Furthermore, the water stressor reduced ADFI during the last 14 d of the trial and cumulatively (P < 0.05). Seven days postweaning there was an increase (P < 0.05) in jejunal villous height to depth ratio due to the feed stressor and a decrease (P < 0.05) in the ileal villous height to depth ratio due to the water stressor. There was an increase (P < 0.05) in serum cortisol levels due to the water stressor both 1 and 7 d postweaning. Furthermore, there was an increase in serum corticotrophin-releasing factor 1 d but not 7 d postweaning due to the water stressor (P < 0.05). The feed stressor reduced (P < 0.05) TNF-? gene expression, and the water stressor reduced (P < 0.05) OC gene expression in the jejunum 1 d postweaning. In the ileum, there was a reduction in CL-1 and ZO-1 gene expression (P < 0.05) due to the water stressor 7 d postweaning. The results from the current investigation showed that a 24-h feed or water deprivation at the time of weaning has negative impacts on growth performance, intestinal characteristics, and serum stress responses immediately following the stress event and throughout the nursery period. PMID:25184845

Horn, N; Ruch, F; Miller, G; Ajuwon, K M; Adeola, O

2014-10-01

403

Water consumption characteristics and water use efficiency of winter wheat under long-term nitrogen fertilization regimes in northwest China.  

PubMed

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

Zhong, Yangquanwei; Shangguan, Zhouping

2014-01-01

404

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...

405

Molecular Dynamics Simulation of Sodium Dodecyl Sulfate Micelle in Water: Micellar Structural Characteristics and Counterion Distribution  

E-print Network

Molecular Dynamics Simulation of Sodium Dodecyl Sulfate Micelle in Water: Micellar Structural An all-atom 5 nanosecond molecular dynamics simulation of a water-solvated micelle containing 60 sodium, and the orientation of the monomers toward the micelle center of mass were evaluated. The results indicate a stable

Perera, Lalith

406

Water Quality, Fishery, and Biologic Characteristics in a Shallow, Eutrophic Lake with Dense Macrophyte Populations  

Microsoft Academic Search

Giffin Lake is a shallow, eutrophic lake in south central Washington and the sub ject of an intensive Phase I restoration diagnostic\\/feasibility study. Water quality problems in the lake have been manifested principally as excessive growth of the floating-leaved macrophyte, Nymphaea odorata, white water lily. Study results indicate that these macrophytes play a central role in chemical, physical, and biological

Barry C. Moore; William H. Funk; Eric Anderson

1994-01-01

407

Chemical Characteristics of Water Masses in the Amerasian Basin of the Arctic Ocean  

Microsoft Academic Search

Detailed vertical profiles of hydrographic data and routine chemical parameters (oxygen, nutrients) were taken in the Amerasian basin of the Arctic Ocean and in the Bering Strait and Chukchi Sea. Correlations of these chemical profiles with water mass sources and mixing processes are postulated. The chemical parameters show that the water of the sharp temperature maximum at about 75-meter depth

Patrick Kinney; Martin E. Arhelger; David C. Burrell

1970-01-01

408

Characteristics of soil moisture in permafrost observed in East Siberian taiga with stable isotopes of water  

Microsoft Academic Search

Soil moisture and its isotopic composition were observed at Spasskaya Pad experimental forest near Yakutsk, Russia, during summer in 1998, 1999, and 2000. The amount of soil water (plus ice) was estimated from volumetric soil water content obtained with time domain reflectometry. Soil moisture and its 18O showed large interannual variation depending on the amount of summer rainfall. The soil

A. Sugimoto; D. Naito; N. Yanagisawa; K. Ichiyanagi; N. Kurita; J. Kubota; T. Kotake; T. Ohata; T. C. Maximov; A. N. Fedorov

2003-01-01

409

A Study of Characteristics of Water Tree Growth by Electric Field Analysis  

NASA Astrophysics Data System (ADS)

Three-dimensional electric fields analysis was applied to the tip of water trees in XLPE cable. First, pre-breakdown detection was curried out on “needle-shaped” water trees. The results were analyzed by the three-dimensional electric field F.E.M. The water tree was simplified by a spheroid in the analysis. The position of the trees, length, tip radius were read from the microphotographs. The analysis was done on all 11 examples. The test results could be explained well when the conductivity of the water tree region was assumed to be 5×10-7S/m. Next, the electric fields of tip of three kinds of water tree (“blue”, “needle-shaped” and “white” water tree) were analyzed. Three kinds of water tree were expressed by changing the conductivity of water tree region. And, a distance from water trees to inside half conductor was made to change in three kinds. These were analyzed about the cable (insulation thickness: 3, 6, 9 mm) of 6.6, 22, 66 kV respectively. It was found out that “blue” and needle-shaped tree in the 66 kV cable and “blue” tree in the 22 kV cable may cause a breakdown under the operation voltage. As for other cases, the tree may propagate without making breakdown until it bridges the insulation. And, the possibility that the growth of “white” water tree declined rapidly in 66, the 22 kV cable when it touches inner semi-conducting layer so that the tip electric fields of the tree are the same as the average electric fields of the cable was suggested.

Nakade, Masahiko; Inoue, Daisuke

410

Chemical characteristics of Delaware River water, Trenton, New Jersey, to Marcus Hook, Pennsylvania  

USGS Publications Warehouse

This progress report gives the results of an investigation of the quality of water in the Delaware River from Trenton, N. J. to Marcus Hook, Pa., for the period August 1949 to December 1952. The Delaware River is the principal source of water for the many industries and municipal water supplies along this reach of the river and both industries and municipalities use it for the disposal of their wastes. Consequently, a study of the quality of the water and variations in the quality caused by changes in streamflow, tidal effects, pollution and other factors is important to the many users. In both New Jersey and Pennsylvania steps are being taken to abate pollution, thus it is of more than passing interest to measure the effects of waste treatment on the quality of the Delaware River water. At average or higher rates of streamflow the mineral content of the water increases slightly from Trenton to Marcus Hook. There is little variation in the concentration of dissolved minerals from bank to bank or from top to bottom of the river. At times of protracted low rates of flow the effect of ocean water mixing with the river water may be noted as far upstream as Philadelphia. At such times the salinity is often greater near the bottom of the river than near the top. The increase in chloride concentration upstream from Philadelphia is small compared to the rapid increase downstream from Philadelphia. Temperatures of offshore water vary with the season, but on a given day are substantially uniform throughout the reach of the river from Trenton to Marcus Hook. The water contains less dissolved oxygen as it flows downstream indicating that oxygen is being consumed by oxidizable matter. From Philadelphia downstream there are periods, especially in late summer, when the dissolved oxygen is barely sufficient to meet the oxygen demands of the pollution load.

Durfor, Charles N.; Keighton, W.B.

1954-01-01

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Water use characteristics of black mangrove (Avicennia germinans) communities along an ecotone with marsh at a northern geographical limit  

USGS Publications Warehouse

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.

Krauss, Ken W.; McKee, Karen L.; Hester, Mark W.

2014-01-01