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


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



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


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



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


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

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



The effect of water stress on some morphological, physiological, and biochemical characteristics and bud success on apple and quince rootstocks.  


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



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



Water characteristics  

Microsoft Academic Search

Recent research on water characteristics is cited in this review article. Acid precipitation has been noted as one of the major environmental problems of the current decade. It poses a serious challenge to national and international bodies to protect water quality. Considerable interest was voiced in 1980 over the causes and effects, prevention and control of acid rain. One study



Applied physiology of water-skiing.  


Water-skiing is a physically demanding sport involving highly coordinated movements, extreme upper body torques, sustained isometric contractions and near maximal stresses on the anaerobic system. Due to the physical demands of the sport, elite skiers have developed physiological characteristics similar to other elite athletes. However, until recently little research has focused on the kinesiology, physiology and physical conditioning of water-skiing. PMID:8726345

Leggett, S H; Kenney, K; Eberhardt, T



Fish Physiology, Toxicology, and Water Quality  

E-print Network

Fish Physiology, Toxicology, and Water Quality Proceedings of the Ninth International/010 February 2007 Fish Physiology, Toxicology, and Water Quality Proceedings of the Ninth International International Symposium on Fish Physiology, Toxicology, and Water Quality. The subject of the meeting

DeWitt, Thomas J.


Physiological water model development  

NASA Technical Reports Server (NTRS)

The water of the human body can be categorized as existing in two main compartments: intracellular water and extracellular water. The intracellular water consists of all the water within the cells and constitutes over half of the total body water. Since red blood cells are surrounded by plasma, and all other cells are surrounded by interstitial fluid, the intracellular compartment has been subdivided to represent these two cell types. The extracellular water, which includes all of the fluid outside of the cells, can be further subdivided into compartments which represent the interstitial fluid, circulating blood plasma, lymph, and transcellular water. The interstitial fluid surrounds cells outside of the vascular system whereas plasma is contained within the blood vessels. Avascular tissues such as dense connective tissue and cartilage contain interstitial water which slowly equilibrates with tracers used to determine extracellular fluid volume. For this reason, additional compartments are sometimes used to represent these avascular tissues. The average size of each compartment, in terms of percent body weight, has been determined for adult males and females. These compartments and the forces which cause flow between them are presented. The kidneys, a main compartment, receive about 25 percent of the cardiac output and filters out a fluid similar to plasma. The composition of this filtered fluid changes as it flows through the kidney tubules since compounds are continually being secreted and reabsorbed. Through this mechanism, the kidneys eliminate wastes while conserving body water, electrolytes, and metabolites. Since sodium accounts for over 90 percent of the cations in the extracellular fluid, and the number of cations is balanced by the number of anions, considering the renal handling sodium and water only should sufficiently describe the relationship between the plasma compartment and kidneys. A kidney function model is presented which has been adapted from a previous model of normal renal function in man. To test the validity of the proposed kidney model, results predicted by the model will be compared to actual data involving injected or ingested fluids and subsequent urine flow rates. Comparison of the model simulation to actual data following the ingestion of 1 liter of water is shown. The model simulation is also shown with actual data following the intravenous infusion of hypertonic saline.

Doty, Susan



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.



Peach leaf physiology and irrigation water and light availability  

Microsoft Academic Search

We studied the effect of available water and light into the canopy on leaf characteristics and physiology of two clingstone peach cvs. Irrigation water was reduced by 90% (deficit) since late June (3 weeks before harvest) and, the same day, 1.2 m wide Extenday reflective mulch strip was applied on the row. Incident and reflected ultraviolet (UV) and photosynthetically active

E. Pliakoni; H. Kalorizou; G. D. Nanos


Physiological characteristics of international female soccer players.  


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




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...



EPA Science Inventory

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


Physiological Characteristics of Well-Trained Junior Sprint Kayak Athletes.  


This study aimed to profile the physiological characteristics of junior Sprint Kayak athletes (n=21, VO2max - 4.1±0.7 L·min-1, training experience - 2.7±1.2 y), and to establish the relationship between physiological variables (VO2max, VO2kinetics, muscle oxygen kinetics, paddling efficiency) and Sprint Kayak performance. VO2max, power at VO2max (MAP), power:weight ratio, paddling efficiency and VO2 at lactate threshold (VO2LT) and whole body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200-m and 1000-m. Large-to-nearly perfect (-0.5 to -0.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate-to-very large correlations (-0.4 to -0.7) with 200 and 1000-m performance. In addition, trivial-to-large correlations (0.11 to -0.5) were observed between muscle oxygenation parameters, muscle and whole body oxygen kinetics and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle de-oxygenation, and maximal aerobic power (p<0.001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and HHb (p<0.001). The present findings showed that well-trained junior Sprint Kayak athletes possess a high level of relative aerobic fitness and highlights the importance of the peripheral muscle metabolism for Sprint Kayak performance, particularly in 200-m races where finalists and non-finalists are separated by very small margins. Such data highlights the relative aerobic fitness variables that can be used as benchmarks for talent identification programs or monitoring longitudinal athlete development. However, such approaches need further investigations. PMID:25473923

Oliveira Borges, Thiago; Dascombe, Ben; Bullock, Nicola; Coutts, Aaron J



The Clinical Physiology of Water Metabolism  

PubMed Central

Water balance is tightly regulated within a tolerance of less than 1 percent by a physiologic control system located in the hypothalamus. Body water homeostasis is achieved by balancing renal and nonrenal water losses with appropriate water intake. The major stimulus to thirst is increased osmolality of body fluids as perceived by osmoreceptors in the anteroventral hypothalamus. Hypovolemia also has an important effect on thirst which is mediated by arterial baroreceptors and by the renin-angiotensin system. Renal water loss is determined by the circulating level of the antidiuretic hormone, arginine vasopressin (AVP). AVP is synthesized in specialized neurosecretory cells located in the supraoptic and paraventricular nuclei in the hypothalamus and is transported in neurosecretory granules down elongated axons to the posterior pituitary. Depolarization of the neurosecretory neurons results in the exocytosis of the granules and the release of AVP and its carrier protein (neurophysin) into the circulation. AVP is secreted in response to a wide variety of stimuli. Change in body fluid osmolality is the most potent factor affecting AVP secretion, but hypovolemia, the renin-angiotensin system, hypoxia, hypercapnia, hyperthermia and pain also have important effects. Many drugs have been shown to stimulate the release of AVP as well. Small changes in plasma AVP concentration of from 0.5 to 4 ?U per ml have major effects on urine osmolality and renal water handling. ImagesFigure 5.Figure 12.Figure 15.Figure 16. PMID:394480

Weitzman, Richard E.; Kleeman, Charles R.



Crop Physiology  

Microsoft Academic Search

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

Walter Zegada-Lizarazu; Stan D Wullschleger; S. Surendran Nair; Andrea Monti



Physiological characteristics of skeletal muscles of dogs and cats.  


Our purpose was to determine if physiological characteristics of skeletal muscles of dogs and cats are related to their histochemical and biochemical characteristics. Maximum oxygen consumption (VO2max) and blood flow (Q) at VO2max were determined for in situ muscles of dogs and cats. Compared to cat muscles, dog muscles per unit mass had higher succinate oxidase activities, VO2max's, and Q's at VO2max's. There are positive relationships between Q at VO2max and VO2max and between VO2max and succinate oxidase activity. The higher VO2max's and succinate oxidase activities of dog muscles are consistent with the presence in these muscles of only slow-twitch fatique-resistant fibers and fast-twitch fatique-resistant fibers, whereas up to 50% of the fibers found in cat muscles are fast-twitch fatiqable. Capillary-to-fiber ratios are 2.40-2.97 for dog muscles compared to 2.17-2.84 for cat muscles. Thus the two- to threefold higher Q at VO2max for dog muscles compared to cat muscles is not due to a greater number of capillaries. PMID:879310

Maxwell, L C; Barclay, J K; Mohrman, D E; Faulkner, J A



Physiological and perceptual responses to backward and forward treadmill walking in water  

Microsoft Academic Search

We compared physiological and perceptual responses, and stride characteristics while walking backward in water with those of walking forward in water. Eight males walked on an underwater treadmill, immersed to their xiphoid process level. Oxygen uptake (V?O2), respiratory exchange ratio (R), heart rate (HR), minute ventilation (V?E), blood lactate concentration (BLa), ratings of perceived exertion (RPE: for breathing and legs,

Kenji Masumoto; Ayako Hamada; Hiro-omi Tomonaga; Kana Kodama; Yuko Amamoto; Yoshiko Nishizaki; Noboru Hotta



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.



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


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




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...


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



[Effects of flooding on the photosynthetic physiology characteristics of Pterocarya stenoptera seedlings].  


Three water treatments (control, CK; continuous flooding, CF; and periodic flooding, PF) were installed to simulate the soil moisture change of the riparian zone in the Three Gorges Reservoir (TGR) region of China to study the physiological and ecological adaptation mechanisms of the native plant species Pterocarya stenoptera seedlings to the soil moisture change. All the water treatments had significant effects on the photosynthesis, biomass accumulation, and growth of the P. stenoptera seedlings. As compared with those in CK, the seedling's net photosynthetic rate (Pn) and stomatal conductance (gs) in treatments CF and PF were significantly lower while the intercellular carbon dioxide concentration was significantly higher, and the Pn and gs in CF and PF declined initially followed by a gradual recovery or tended to be stable. With the extension of treatment time, the total biomass and root-, stem-, and leaf biomass, plant height, and basal diameter in CF and PF all presented an increasing trend. Throughout the experimental period, the total biomass, root- and leaf biomass, and plant height in CF and PF and the stem biomass in PF were significantly lower than those in CK, whereas the stem biomass in CF had no significant difference with that in CK, though the basal diameter in CF was significantly higher than that in CK. It was suggested that the P. stenoptera seedlings had the physiological and ecological characteristics of tolerating flooding rather than flooding-drought alteration. PMID:23755480

Wang, Chao-Ying; Li, Chang-Xiao; Zhang, Ye



Contrasting Physiological Responses of Six Eucalyptus Species to Water Deficit  

PubMed Central

Background and Aims The genus Eucalyptus occupies a broad ecological range, forming the dominant canopy in many Australian ecosystems. Many Eucalyptus species are renowned for tolerance to aridity, yet inter-specific variation in physiological traits, particularly water relations parameters, contributing to this tolerance is weakly characterized only in a limited taxonomic range. The study tests the hypothesis that differences in the distribution of Eucalyptus species is related to cellular water relations. Method Six eucalypt species originating from (1) contrasting environments for aridity and (2) diverse taxonomic groups were grown in pots and subjected to the effects of water deficit over a 10-week period. Water potential, relative water content and osmotic parameters were analysed by using pressure–volume curves and related to gas exchange, photosynthesis and biomass. Key Results The six eucalypt species differed in response to water deficit. Most significantly, species from high rainfall environments (E. obliqua, E. rubida) and the phreatophyte (E. camaldulensis) had lower osmotic potential under water deficit via accumulation of cellular osmotica (osmotic adjustment). In contrast, species from low rainfall environments (E. cladocalyx, E. polyanthemos and E. tricarpa) had lower osmotic potential through a combination of both constitutive solutes and osmotic adjustment, combined with reductions in leaf water content. Conclusions It is demonstrated that osmotic adjustment is a common response to water deficit in six eucalypt species. In addition, significant inter-specific variation in osmotic potential correlates with species distribution in environments where water is scarce. This provides a physiological explanation for aridity tolerance and emphasizes the need to identify osmolytes that accumulate under stress in the genus Eucalyptus. PMID:17905722

Merchant, Andrew; Callister, Andrew; Arndt, Stefan; Tausz, Michael; Adams, Mark



[Effect of drought stress on growth and physiological-biochemical characteristics of Stellaria dichotoma].  


A pot experiment was conducted to study effect of drought stress on leaf physiological characteristics and growth of one year old Stellaria dichotoma seedlings. The result showed that plant height and shoot dry weight significantly decreased with decrease in soil water content; however, root length and root dry weight increased at light drought stress and decreased at severe drought stress. The result also showed that with the decrease of soil water content, proline content in S. dichotoma leaves decreased then increase, while solube protein content decreased. Activities of SOD and POD in S. dichotoma leaves significantly decreased as soil water content decreased, while activity of CAT significantly decreased at severe drought stress. Membrane permeability in S. dichotoma leaves increased, while MDA content decreased then increased as soil water decreased. These results suggest that S. dichotoma had osmotic stress resistance ability and reactive oxygen scavenging capacity at light drought stress, which caused S. dichotoma growth was no inhibited at a certain extent drought stress. PMID:25272829

Lang, Duo-Yong; Cui, Jia-Jia; Da, Zhou; Li, Yue-Tong; Zhou, Li; Zhang, Xin-Hui



Physiological characteristics of mercury uptake by two estuarine species  

USGS Publications Warehouse

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

Luoma, S.N.



Dynamic characteristics of silver nanoparticles in physiological fluids: toxicological implications.  


The field of nanotoxicology has made tremendous progress identifying novel and potentially adverse biological effects following nanomaterial (NM) exposure. However, one facet yet to be satisfactorily explored is how a physiological environment modifies NM physicochemical properties, thus introducing novel complexities associated with solid phase material exposures. In this study, artificial alveolar, lysosomal, and interstitial fluids were used to identify environmental-specific modulations to the properties and behavior of hydrocarbon-coated (Ag-HC) and polysaccharide-coated (Ag-PS) silver NMs. As inhalation is a common route of exposure, an alveolar macrophage cell model with deposition dosages representing approximately 2.5 months and 10 years of occupational exposure (0.5 and 25 ng/mL, respectively) were employed. Following dispersion in the artificial fluids, the Ag-HC and Ag-PS NMs demonstrated significant alterations to morphology, aggregation patterns, and particle reactivity. However, the Ag-PS also demonstrated a loss of particle coating, which elicited increased cytotoxicity, phagocytosis, and inflammation not associated with the original Ag-PS. This study demonstrated that in a physiological system NMs undergo considerable modulation, introducing a scenario where the toxicity of NMs may increase over time due to internal bioconditions. These findings highlight the critical influence that the dynamic and insoluble nature of NMs have on bioeffects and the importance of characterizing this behavior. PMID:25496452

Braydich-Stolle, Laura K; Breitner, Emily K; Comfort, Kristen K; Schlager, John J; Hussain, Saber M



Physiological and perceptual responses to backward and forward treadmill walking in water.  


We compared physiological and perceptual responses, and stride characteristics while walking backward in water with those of walking forward in water. Eight males walked on an underwater treadmill, immersed to their xiphoid process level. Oxygen uptake ((.)V(O2)), respiratory exchange ratio (R), heart rate (HR), minute ventilation ((.)V(E)), blood lactate concentration (BLa), ratings of perceived exertion (RPE: for breathing and legs, RPE-Br and RPE-Legs, respectively), blood pressure (for systolic and diastolic pressures, SBP and DBP, respectively), and step frequency (SF) were measured. In addition, step length (SL) was calculated. (.)V(O2), R, HR, V (E), BLa, RPE-Br, RPE-Legs, and SBP were significantly higher while walking backward in water than when walking forward in water (P<0.05). Furthermore, SF was significantly higher (P<0.001) and SL was significantly lower (P<0.001) while walking backward in water, compared to walking forward in water. These results indicate that walking backward in water elicits higher physiological and perceptual responses than those produced when walking forward in water at the same speed. PMID:18829319

Masumoto, Kenji; Hamada, Ayako; Tomonaga, Hiro-Omi; Kodama, Kana; Amamoto, Yuko; Nishizaki, Yoshiko; Hotta, Noboru




ERIC Educational Resources Information Center

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

Kay, Ian



Characteristics of solar water pumping in Jordan  

Microsoft Academic Search

Remote underground water wells were investigated and 13 such wells were chosen for this study. Photovoltaic (PV) generators were used to power pumping the water up to the surface tanks to be used. A design method was established and illustrated depending on a pumping factor (Fp) which is a function of the solar characteristics. A laboratory solar water pumping unit

M. A. Hammad



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


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


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



Water relation characteristics of Calligonum and consequences for a sustainable management of vegetation in the southern fringe of Takelamakan Desert  

Microsoft Academic Search

On field sites, water physiological characteristics of the desert legume Calligonum were investigated during the vegetation period in 1999(2000) in the southern fringe of the Takelamakan Desert, Xinjiang, NW China. The seasonal variation of predawn water potentials and of diurnal water potential indicated that Calligonum plants were well water supplied and it has stronger ability to maintain the water balance

Fanjiang Zeng; Ximing Zhang; Andrea Foetzki; Xiangyi Li; Xioaming Li; Michael Runge



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


Pre?season physiological characteristics of English first and second division soccer players  

Microsoft Academic Search

This investigation was undertaken in an effort to establish physiological characteristics of soccer players and to relate them to positional roles. A total of 135 footballers (age 24.4 ± 4.6 years) were assessed for body mass, % body fat, haemoglobin, maximal oxygen uptake (VO2 max), leg power, anaerobic capacity and speed prior to an English league season. The sample included

J. A. Davis; J. Brewer; D. Atkin



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

Technology Transfer Automated Retrieval System (TEKTRAN)

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


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



Physiological evidence that pyramidal neurons lack functional water channels.  


The physiological conditions that swell mammalian neurons are clinically important but contentious. Distinguishing the neuronal component of brain swelling requires viewing intact neuronal cell bodies, dendrites, and axons and measuring their changing volume in real time. Cultured or dissociated neuronal somata swell within minutes under acutely overhydrated conditions and shrink when strongly dehydrated. But paradoxically, most central nervous system (CNS) neurons do not express aquaporins, the membrane channels that conduct osmotically driven water. Using 2-photon laser scanning microscopy (2PLSM), we monitored neuronal volume under osmotic stress in real time. Specifically, the volume of pyramidal neurons in cerebral cortex and axon terminals comprising cerebellar mossy fibers was measured deep within live brain slices. The expected swelling or shrinking of the gray matter was confirmed by recording altered light transmittance and by indirectly measuring extracellular resistance over a wide osmotic range of -80 to +80 milliOsmoles (mOsm). Neurons expressing green fluorescent protein were then imaged with 2PLSM between -40 and +80 mOsm over 20 min. Surprisingly, pyramidal somata, dendrites, and spines steadfastly maintained their volume, as did the cerebellar axon terminals. This precluded a need for the neurons to acutely regulate volume, preserved their intrinsic electrophysiological stability, and confirmed that these CNS nerve cells lack functional aquaporins. Thus, whereas water easily permeates the aquaporin-rich endothelia and glia driving osmotic brain swelling, neurons tenatiously maintain their volume. However, these same neurons then swell dramatically upon oxygen/glucose deprivation or [K+]0 elevation, so prolonged depolarization (as during stroke or seizure) apparently swells neurons by opening nonaquaporin channels to water. PMID:16723408

Andrew, R David; Labron, Mark W; Boehnke, Susan E; Carnduff, Lisa; Kirov, Sergei A



Behaviour during elevated water temperatures: can physiology explain movement of juvenile Atlantic salmon to cool water?  


1. Temperature governs most physiological processes in animals. Ectotherms behaviourally thermoregulate by selecting habitats with temperatures regulating their body temperature for optimal physiological functioning. However, ectotherms can experience temperature extremes forcing the organisms to seek temperature refuge. 2. Fish actively avoid potentially lethal temperatures by moving to cool-water sites created by inflowing tributaries and groundwater seeps. Juvenile Atlantic salmon (Salmo salar) of different age classes exhibit different behavioural responses to elevated temperatures (>23 °C). Yearling (1+) and 2-year-old (2+) Atlantic salmon often cease feeding, abandon territorial behaviour and swim continuously in aggregations in cool-water sites; whereas young-of-the-year (0+) fish continue defending territories and foraging. 3. This study determined whether the behavioural shift in older individuals (2+) occurred when basal metabolic rate, driven by increasing water temperature, reached the maximum metabolic rate such that anaerobic pathways were recruited to provide energy to support vital processes. Behaviour (feeding and stress responses), oxygen consumption, muscle lactate and glycogen, and circulating blood lactate and glucose concentrations were measured in wild 0+ and 2+ Atlantic salmon acclimated to water temperatures between 16 and 28 °C. 4. Results indicate that oxygen consumption of the 2+ fish increased with temperature and reached a plateau at 24 °C, a temperature that corresponded to cessation of feeding and a significant increase in muscle and blood lactate levels. By contrast, oxygen consumption in 0+ fish did not reach a plateau, feeding continued and muscle lactate did not increase, even at the highest temperatures tested (28 °C). 5. To conclude, the experiment demonstrated that the 0+ and 2+ fish had different physiological responses to the elevated water temperatures. The results suggest that wild 2+ Atlantic salmon employ behavioural responses (e.g. movement to cool-water sites) at elevated temperatures in an effort to mitigate physiological imbalances associated with an inability to support basal metabolism through aerobic metabolic processes. PMID:21401593

Breau, Cindy; Cunjak, Richard A; Peake, Stephan J



Study on precision water-saving irrigation automatic control system by plant physiology  

Microsoft Academic Search

Olympic games in 2008 is not only a world sports event, but also a great opportunity to show our current level of economic development and modern science and technology strength. Precision water-saving irrigation automatic control system by plant physiology this paper described is one of the Olympic games facilities projects, which takes standards of water plant physiologically need and soil

Yandong Zhao; Junfu Zhang; Jinfeng Guan; Weilun Yin



Physical characteristics and physiological attributes of female volleyball players--the need for individual data.  


The purpose of this study was twofold: (a) to profile physical characteristics and physiological attributes of adolescent and adult Greek female volleyball players (n = 61) who were members of the A (the best league for female volleyball players) and B (the second-best league for female volleyball players) Series clubs in Greece and (b) to examine the intraindividual variability among these players in all physical and physiological measurements that were undertaken in the study. The participants were divided into 3 age groups--under 14, 14-18, and over 18 years. They underwent a series of physical (e.g., height, body mass, and percentage of body fat) and physiological (e.g., aerobic profile, flexibility, and vertical jumping ability) tests. Three main findings emerged from the data analysis: (a) differences in physical characteristics and physiological attributes existed between the 3 age groups. For example, fat-free mass was lower in players under the age of 14 years (41.57 ± 6.06 kg) compared with that in players between the ages of 14-18 years (50.24 ± 6.96 kg) and players over the age of 18 years (52.03 ± 3.39 kg). In addition, the relative peak power as measured in the Wingate Anaerobic Test was the highest in the over-18 group (9.72 ± 0.65 W·kg), lower in the 14-18 group (8.95 ± 0.7), and the lowest in the under-14 group (8.32 ± 0.78 W·kg), (b) large intraindividual variability existed in most physical characteristics and physiological attributes measured in the study, and (c) the intraindividual variability was observed in all the 3 groups. These findings emphasize the need for coaches to examine the intraindividual variability within the players on their teams and to use this information when designing training programs and strength and conditioning programs. PMID:22076096

Nikolaidis, Pantelis T; Ziv, Gal; Arnon, Michal; Lidor, Ronnie



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

Microsoft Academic Search

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

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



Eco-physiological characteristics of Pistia stratiotes and its removal of pollutants from livestock wastewater.  


The effectiveness of water lettuce in removing pollutants including organic pollutants, nitrogen (NH3-N) and total phosphorus (TP) from livestock wastewater along with the physiological effects and their correlations, was studied for the first time. The results showed that the water lettuce had higher removal efficiency with low concentrations of livestock wastewater. The removal efficiency of water lettuce for different initial concentrations of livestock wastewater within 8 d was as follows: chemical oxygen demand (CODcr) (68-82%) > NH3-N (57-69%) >TP (27-45%). The speed of purification of water lettuce for CODcr, NH3-N and TP conformed to first order kinetics equations. The water quality indices CODcr, NH3-N and TP had a higher linear correlation with peroxidase (POD) activity (R(2) > 0.9(2)) than with superoxide dismutase (SOD) and catalase (CAT) activity, which indicates that the main reacting enzyme of water lettuce under high CODcr stress is peroxidase. PMID:24960015

Chen, Jinfa; Nie, Qishan; Zhang, Yun; Hu, Jinzhao; Qing, Lin



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



Physical characteristics and physiological attributes of adolescent volleyball players-a review.  


The purpose of this article was to review a series of studies (n = 31) on physical characteristics, physiological attributes, and volleyball skills of female and male adolescent volleyball players. Among the main findings were (a) that male national players were taller and heavier than state and novice players, while female national players showed lower body fat values compared with state and novice players, and (b) vertical jump values were higher in starters versus nonstarters. Among the methodological concerns based on the reviewed studies were the lack of information on maturational age and lack of longitudinal studies. It was recommended that a careful selection of physiological tests should be made when assessing the abilities of adolescent volleyball players. PMID:20332545

Lidor, Ronnie; Ziv, Gal



The physiology and toxicology of salmonid eggs and larvae in relation to water quality criteria  

Microsoft Academic Search

The purpose of this review is to collate physiological knowledge on salmonid eggs and larvae in relation to water quality criteria. Salmonid genera reviewed include Coregonus, Thymallus, Salvelinus, Salmo, and Oncorhynchus spp. When physiological data for salmonids are lacking, the zebrafish and medaka models are included. The primary focus is on the underlying mechanisms involved in the hydro-mineral, thermal, and

Roderick Nigel Finn



Modeling PCB transfer into hen eggs: Influence of physiological characteristics of the animal.  


Laying hens are likely to be exposed to a wide range of persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs). To improve the safety of poultry farming systems in terms of POPs, the present research focused on assessing the impact of physiological characteristics of the hen on the transfer of ingested PCBs to eggs. Modeling was used as a research tool to explore the impact of some physiological characteristics on the transfer of PCBs in the laying hen. The mathematical model simulates the dynamics of the size of the lipid compartments in the animal and the frequency of laying, with the PCB concentrations in egg yolk and adipose tissue being model outputs. Simulations were run to assess effects of animal characteristics on the transfer of PCBs to eggs. Laying rate proportionally influenced the PCB level of eggs and adipose tissue at steady state. Body fat diluted absorbed PCBs in the absence of laying and significantly influenced the decontamination rate of tissues during depuration after an exposure period. Application of the present model to actual exposure cases highlights its value in improving the support of risk management in livestock farming. Environ Toxicol Chem 2015;34:173-183. © 2014 SETAC. PMID:25323569

Fournier, Agnès; Martin, Olivier; Travel, Angélique; Puillet, Laurence; Feidt, Cyril; Jondreville, Catherine



[Physiological and biochemical characteristics of immobilized champagne yeasts and their participation in sparkling processes].  


Methods for immobilizing champagne yeasts, physiological and biochemical characteristics of the immobilized cells, and problems of their utilization in the production of quality champagne wines are reviewed. Studies aimed at the development of efficient biocatalysts for champaignizing wines using bottle fermentation (method champenoise) and tank processing (bulk, or Charmat process), based on the use of immobilized yeast cells, are described. Data on the industrial use of such biocatalysts in countries manufacturing champagne wines are presented. Problems and prospects of further research in this field are discussed. PMID:14593861

Martynenko, N N; Gracheva, I M



The Effects of Water Temperature Change on Goldfish Physiology and Behavior  

NSDL National Science Digital Library

In this activity, students determine the effects of temperature on physiological and behavioral changes in fish. Students design an experiment to measure the effects of changing water temperature on fish respiration and then an experiment examining the relationship between water temperature and another approved physiological or behavioral variable. In addition, students create a poster demonstration communicating the results and conduct an experiment demonstrating proper maintenance and care of live animals.

Melinda Pittis (Lexington School for the Deaf)



Effects of age on the physiological and mechanical characteristics of human femoropopliteal arteries.  


Surgical and interventional therapies for peripheral artery disease (PAD) are notorious for high rates of failure. Interactions between the artery and repair materials play an important role, but comprehensive data describing the physiological and mechanical characteristics of human femoropopliteal arteries are not available. Fresh femoropopliteal arteries were obtained from 70 human subjects (13-79years old), and in situ vs. excised arterial lengths were measured. Circumferential and longitudinal opening angles were determined for proximal superficial femoral, proximal popliteal and distal popliteal arteries. Mechanical properties were assessed by multi-ratio planar biaxial extension, and experimental data were used to calculate physiological stresses and stretches, in situ axial force and anisotropy. Verhoeff-Van Gieson-stained axial and transverse arterial sections were used for histological analysis. Most specimens demonstrated nonlinear deformations and were more compliant longitudinally than circumferentially. In situ axial pre-stretch decreased 0.088 per decade of life. In situ axial force and axial stress also decreased with age, but circumferential physiological stress remained constant. Physiological circumferential stretch decreased 55-75% after 45years of age. Histology demonstrated a thickened external elastic lamina with longitudinally oriented elastin that was denser in smaller, younger arteries. Axial elastin likely regulates axial pre-stretch to help accommodate the complex deformations required of the artery wall during locomotion. Degradation and fragmentation of elastin as a consequence of age, cyclic mechanical stress and atherosclerotic arterial disease may contribute to decreased in situ axial pre-stretch, predisposing to more severe kinking of the artery during limb flexion and loss of energy-efficient arterial function. PMID:25301303

Kamenskiy, Alexey V; Pipinos, Iraklis I; Dzenis, Yuris A; Phillips, Nicholas Y; Desyatova, Anastasia S; Kitson, Justin; Bowen, Robert; MacTaggart, Jason N



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

PubMed Central

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

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



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



Water Landing Characteristics of a Reentry Capsule  

NASA Technical Reports Server (NTRS)

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



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


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



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


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

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



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



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

PubMed Central

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

Hyun, Se-Hee



Physiological characteristics of tropical rain forest tree species: A basis for the development of silvicultural technology  

PubMed Central

The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as “the steady state of the diffuse light” and “the turning point” were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of “the bare-root seedlings”, the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests. PMID:18941286

SASAKI, Satohiko



Methane emissions from beef and dairy cattle: quantifying the effect of physiological stage and diet characteristics.  


The prediction of methane outputs from ruminant livestock data at farm, national, and global scales is a vital part of greenhouse gas calculations. The objectives of this work were to quantify the effect of physiological stage (lactating or nonlactating) on predicting methane (CH4) outputs and to illustrate the potential improvement for a beef farming system of using more specific mathematical models to predict CH4 from cattle at different physiological stages and fed different diet types. A meta-analysis was performed on 211 treatment means from 38 studies where CH4, intake, animal, and feed characteristics had been recorded. Additional information such as type of enterprise, diet type, physiological stage, CH4 measurement technique, intake restriction, and CH4 reduction treatment application from these studies were used as classificatory factors. A series of equations for different physiological stages and diet types based on DMI or GE intake explained 96% of the variation in observed CH4 outputs (P<0.001). Resulting models were validated with an independent dataset of 172 treatment means from 20 studies. To illustrate the scale of improvement on predicted CH4 outputs from the current whole-farm prediction approach (Intergovernmental Panel on Climate Change [IPCC]), equations developed in the present study (NewEqs) were compared with the IPCC equation {CH4 (g/d)=[(GEI×Ym)×1,000]/55.65}, in which GEI is GE intake and Ym is the CH4 emission factor, in calculating CH4 outputs from 4 diverse beef systems. Observed BW and BW change data from cows with calves at side grazing either hill or lowland grassland, cows and overwintering calves and finishing steers fed contrasting diets were used to predict energy requirements, intake, and CH4 outputs. Compared with using this IPCC equation, NewEqs predicted up to 26% lower CH4 on average from individual lactating grazing cows. At the herd level, differences between equation estimates from 10 to 17% were observed in total annual accumulated CH4 when applied to the 4 diverse beef production systems. Overall, despite the small number of animals used it was demonstrated that there is a biological impact of using more specific CH4 prediction equations. Based on this approach, farm and national carbon budgets will be more accurate, contributing to reduced uncertainty in assessing mitigation options at farm and national level. PMID:24174549

Ricci, P; Rooke, J A; Nevison, I; Waterhouse, A



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


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



Water Landing Characteristics of a Reentry Capsule  

NASA Technical Reports Server (NTRS)

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



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



Physiological and genetic control of water stress tolerance in zoysiagrass  

E-print Network

stomata close which then decreases or stops transpiration and photosynthesis depending on the severity of the stress (Taiz and Zeiger, 2002). On a cellular level, water loss can concentrate solutes, decrease cell volume, disrupt membranes and gradients.... Zoysiagrass has the potential to be more than just the model species for studying turfgrasses. Zoysiagrass has the qualities necessary to argue for its utilization as the model monocot species for studying abiotic stress and C4 photosynthesis. As yield...

Dewey, Daniel Wade



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


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

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



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.




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

Microsoft Academic Search

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

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




Technology Transfer Automated Retrieval System (TEKTRAN)

We evaluated the magnitude of morphological and physiological plasticity in response to contrasting above and below ground resources for the invasive weed, Isatis tinctoria L. (dyer's woad). Plants were grown under low and high levels of light (shade [50% of ambient] and full sun), soil water (50 a...


Estimation of physiological maturity in sunflower as a function of fruit water concentration  

Microsoft Academic Search

Visual methods are commonly used to estimate physiological maturity (PM) in sunflower crops. These methods, while simple and less laborious than following grain dry weight dynamics, are subjective and results can be affected by environmental conditions. The objective of the present work was to study the relationship between the dynamics of dry matter and water concentration (WC) of sunflower fruits,

Déborah P. Rondanini; Roxana Savin; Antonio J. Hall



Plant physiology Role of awns in ear water-use efficiency  

E-print Network

Plant physiology Role of awns in ear water-use efficiency and grain weight in barley J Bort leaves were measured 3 times during grain filling: 1, 3 and 4 weeks after anthesis. The total the WUE of awnless ears during grain filling. The mature kernel dry weight was higher in the awned

Paris-Sud XI, Université de


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

Technology Transfer Automated Retrieval System (TEKTRAN)

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


[Interactive effects of drought and salt stresses on winter wheat seedlings growth and physiological characteristics of stress-resistance].  


In a hydroponic culture, different concentrations of PEG-6000 (0, 8.3%, and 12.6%, W/V) and NaCl (0, 25, and 50 mmol x L(-1) were added to simulate different degrees of drought and salt stresses, aimed to study their interactive effects on the winter wheat (cv. Cang-6001) seedlings growth and physiological characteristics of stress-resistance. The results showed that under the conditions of adding 8.3% and 12.6% of PEG-6000, the addition of 25 mmol NaCl x L(-1) increased the dry matter accumulation and water content in plant, the contents of soluble sugar and soluble protein in leaf and the Na+ content in shoot and root, while decreased the MDA and proline contents in leaf and the K+ content in shoot and root, compared with no NaCl addition. Adding 12.6% of PEG-6000 and 50 mmol x L(-1) of NaCl more inhibited plant growth, compared with no NaCl added. It was suggested that under drought stress, applying definite amount of salt could alleviate the deleterious effects of drought stress on winter wheat seedlings growth. PMID:19565760

Chen, Cheng-Sheng; Xie, Zhi-Xia; Liu, Xiao-Jing



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


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



[Effects of exogenous silicon on physiological characteristics of cucumber seedlings under ammonium stress].  


The present study evaluated the effects of exogenous silicon on growth and physiological characteristics of hydroponically cultured cucumber seedlings under ammonium stress. The results showed that the growth, especially the aerial part growth of cucumber seedlings cultured with ammonium were significantly inhibited than those with nitrate, especially after treatment for 10 d, the aerial part fresh mass of cucumber seedlings were reduced 6.17 g per plant. The accumulation of reactive oxygen species (ROS) was also promoted in cucumber seedlings under ammonium, and the contents of O2*- and H2O2 were significantly increased in cucumber leaves. With the exogenous silicon treatment, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) were significantly improved, the ability to remove reactive oxygen species was enhanced, the contents of O2*- and H2O2 were significantly reduced in cucumber leaves, decreasing the reactive oxygen damage to the cell membrane, and the ratio of electrolyte leakage and the content of MDA in cucumber leaves. Also, with exogenous silicon treatment, the plasma membrane and activity of vacuolar membrane H(+)-ATP was significantly increased, transport capacity of intracellular proton was improved, and the level of ammonium in cucumber body was significantly reduced, thereby reducing the toxicity of ammonium. In conclusion, exogenous silicon could relieve ammonium stress, by increasing the antioxidant enzyme activity, H(+)-ATP activity, and decreasing the ammonium content in cucumber seedlings. PMID:25129941

Gao, Qing-Hai; Wang, Ya-Kun; Lu, Xiao-Min; Jia, Shuang-Shuang



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



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


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



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


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



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 (?



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, Jørgen



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


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



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



Atomization characteristics of coal-water mixtures  

SciTech Connect

There is very little published information on the atomization of coal-water fuels where the presence of solid particles with their own size distribution is expected to affect the process of liquid breakup. This paper presents results obtained on the air atomization of coal-water fuels. A standard air atomizer was used in the experiments. A Malvern particle sizer was used to acquire the drop size distribution. The drop size was measured as a function of the key atomizer parameters, namely, the air pressure and the ratio of fuel and atomizing air mass flow rates. Measurements were made using water to give the baseline and a coal-water mixture with 33 percent of weight coal. Some of the important conclusions are: (1) At similar atomizing conditions (that is, same air pressure and fuel to air mass flow ratio), the mass median diameter for the coal-water mixture was consistently less than that for the water. (2) The difference noted above decreased for low fuel/air mass flow; that is, when the mean diameter became small. (3) The size distribution in both cases seemed to fit well a Rosin-Rammler distribution (within the accuracy of measurement).

Krishna, C.R.; Marnell, P.; Butcher, T.A.



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)



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

NASA Astrophysics Data System (ADS)

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

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



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

Microsoft Academic Search

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

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



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.



Optimal spray characteristics in water spray cooling  

Microsoft Academic Search

The dependence of the efficiency of liquid usage (?) at CHF on spray parameters was experimentally investigated for subcooled water spray cooling. A spray can be characterized by three independent parameters (droplet Sauter-mean diameter, d32, droplet velocity, V, and droplet flux, N). In this study, each of these parameters was varied with the other two kept constant by using a

Ruey-Hung Chen; Louis C. Chow; Jose E. Navedo



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



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


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. PMID:22828893

Mamontov, Eugene; Chu, Xiang-qiang



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


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



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.



Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts.  


The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na(+)- and K(+)-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5·6 and 5·8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5·9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts. PMID:21781105

Liebich, T; McCormick, S D; Kircheis, D; Johnson, K; Regal, R; Hrabik, T



Influence of physiological characteristics on selection in a semi-professional first grade rugby league team: a case study.  


The aim of this study was to determine whether the physiological characteristics of players influence selection in a semi-professional first grade rugby league team. Sixty-six semi-professional rugby league players aged 24+/-4 years (mean +/- s) were monitored over two competitive seasons. The players underwent measurements of body mass, muscular power (vertical jump), speed (10, 20, 30 and 40 m sprint), agility (Illinois agility run) and estimated maximal aerobic power (multi-stage fitness test) 1 week before their first competition match. After selection for either the first or second grade team, the results of all physiological tests were collated and analysed to determine if there were any physiological differences between players selected for the two teams. Players selected to play in the first grade team were significantly (P< 0.05) older (25+/-4 vs 22+/-4 years) and heavier (93+/-10 vs 86+/-10 kg) and had more playing experience (18+/-6 vs 15+/-6 years) than second grade players. Muscular power, speed, agility and estimated maximal aerobic power were not significantly different (P > 0.05) between first grade and second grade players. These results suggest that the physiological capacities of players do not influence selection in a semi-professional first grade rugby league team. Rather, player selection appears to be based on body mass, playing experience and skill. These results support the need for a standardized skills performance test for semi-professional rugby league players. PMID:12043829

Gabbett, Tim J



Chemical characteristics of water masses in the Rockall Trough  

NASA Astrophysics Data System (ADS)

Direct observations of physical and chemical data in the Rockall Trough during February of 2008, 2009 and 2010 are presented. Results are compared to a similar WOCE transect, AR24, completed in November/December 1996. Temperature and salinity data have been used to identify the water masses present in the Trough, and have been combined with nutrient (nitrate, nitrite, phosphate, silicate) and oxygen data to produce a table outlining the chemical characteristics of each of the water masses. Eastern North Atlantic Water (ENAW) moving north through the Trough gains nutrients from a branch of the North Atlantic Current (NAC). Mediterranean Water (MW) was identified as a warm saline core, with characteristically low oxygen and low preformed nutrients along the Irish continental shelf break near 53°N. Found at a similar density level at the southern entrance to the Trough, Sub Arctic Intermediate Water (SAIW) has relatively high oxygen and preformed nutrients, likely entrained from the subpolar gyre when it was formed. LSW was identified as a prominent water mass between 1500 and 2000 m deep, with characteristically high oxygen content. Lower silicate, and to a lesser extent preformed nitrate, in 2009 coincide with a freshening of Labrador Sea Water (LSW) relative to other years, and could indicate a stronger influence from the Labrador Current when it was formed. Finally, traces of Antarctic Bottom Water (AABW) were found as far north as 53°N, indicated by a sharp increase in nutrient concentrations, particularly silicate in the deepest parts of the Trough.

McGrath, Triona; Nolan, Glenn; McGovern, Evin



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


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



Comparative morpho-physiological and biochemical responses of lentil and grass pea genotypes under water stress  

PubMed Central

Background: Both lentil (Lens culinaris Medik.) and grass pea (Lathyrus sativus L.) in the family Fabaceae are two important cool-season food legumes, often experiencing water stress conditions during growth and maturity. Objective: The present study was undertaken to ascertain the response of these two crops under different water stress regimes. Materials and Methods: Different morpho-physiological and biochemical parameters were studied in a pot experiment under controlled environmental conditions. Along with control (proper irrigation, 0 stress), three sets of plants were subjected to mild (6 d), moderate (13 d) and severe (20 d) water stress by withholding irrigation at the appropriate time. Results: Compared with control, plant growth traits and seed yield components reduced significantly in both crops with increasing period of water stress, resulting in lowering of dry mass with more severe effect on lentil compared with grass pea. Foliar Relative Water Content (RWC) (%), K+/Na+ ratio, chlorophyll (chl) a, chl a/b ratio, stomatal conductance and net photosynthetic rate declined considerably in both crops under water stress. Leaf-free proline level increased significantly in both crops, but it decreased markedly in nodules of lentil and remained unchanged in grass pea. Nodulation was also affected due to water stress. The impairment in growth traits and physio-biochemical parameters under water stress was manifested in reduction of drought tolerance efficiency of both crops. Conclusion: Impact of water stress was more severe on lentil compared with grass pea, and modulation of growth traits signified necessity of a detailed strategy in breeding of food legumes under water stress. PMID:24082740

Talukdar, Dibyendu



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


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



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


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

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



Patterns of water use and the tissue water relations in the dioecious shrub, Salix arctica: the physiological basis for habitat partitioning between the sexes.  


Within the high arctic of Canada, Salix arctica, a dioecious, dwarf willow exhibits significant spatial segregation of the sexes. The overall sex ratio is female-biased and female plants are especially common in wet, higher nutrient, but lower soil temperature habitats. In contrast, male plants predominate in more xeric and lower nutrient habitats with higher soil temperatures that can be drought prone. Associated with the sex-specific habitat differences were differences in the seasonal and diurnal patterns of water use as measured by stomatal conductance to water vapor and the bulk tissue water relations of each gender. Within the wet habitats, female plants maintained higher rates of stomatal conductance (g) than males when soil and root temperatures were low (<4° C). In contrast, within the xeric habitats, male plants maintained higher g and had lower leaf water potentials ?leaf at low soil water potentials and a high leaf-to-air vapor pressure gradient (?w) when compared to females. Female plants had more positive carbon isotope ratios than males indicating a lower internal leaf carbon dioxide concentration and possibly higher water use efficiency relative to males. Tissue osmotic and elastic properties also differed between the sexes. Male plants demonstrated lower tissue osmotic potentials near full tissue hydration and at the turgor loss point and a lower bulk tissue elastic modulus (higher tissue elasticity) than female plants. Males also demonstrated a greater ability to osmotically adjust on a diurnal basis than females. These properties allowed male plants to maintain higher tissue turgor pressures at lower tissue water contents and ?soil over the course of the day. The sex-specific distributional and ecophysiological characteristics were also correlated with greater total plant growth and higher fecundity of females in wet habitats, and males in xeric habitats respectively. The intersexual differences in physiology persisted in all habitats. These results and those obtained from growth chamber studies suggest that sex-specific differences have an underlying genetic basis. From these data we conjecture that selection maintaining the intersexual differences may be related to different costs associated with reproduction that can be most easily met through physiological specialization and spatial segregation of the sexes among habitats of differing conditions. PMID:23921398

Dawson, T E; Bliss, L C



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.



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)



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.



Physiological and morphological adaptations in relation to water use efficiency in Mediterranean accessions of Solanum lycopersicum.  


The physiological traits underlying the apparent drought resistance of 'Tomàtiga de Ramellet' (TR) cultivars, a population of Mediterranean tomato cultivars with delayed fruit deterioration (DFD) phenotype and typically grown under non-irrigation conditions, are evaluated. Eight different tomato accessions were selected and included six TR accessions, one Mediterranean non-TR accession (NTR(M)) and a processing cultivar (NTR(O)). Among the TR accessions two leaf morphology types, normal divided leaves and potato-leaf, were selected. Plants were field grown under well-watered (WW) and water-stressed (WS) treatments, with 30 and 10% of soil water capacity, respectively. Accessions were clustered according to the leaf type and TR phenotype under WW and WS, respectively. Correlation among parameters under the different water treatments suggested that potential improvements in the intrinsic water-use efficiency (A(N)/g(s)) are possible without negative impacts on yield. Under WS TR accessions displayed higher A(N)/g(s), which was not due to differences in Rubisco-related parameters, but correlated with the ratio between the leaf mesophyll and stomatal conductances (g(m)/g(s)). The results confirm the existence of differential traits in the response to drought stress in Mediterranean accessions of tomato, and demonstrate that increases in the g(m)/g(s) ratio would allow improvements in A(N)/g(s) in horticultural crops. PMID:20955222

Galmés, Jeroni; Conesa, Miquel Àngel; Ochogavía, Joan Manuel; Perdomo, Juan Alejandro; Francis, David M; Ribas-Carbó, Miquel; Savé, Robert; Flexas, Jaume; Medrano, Hipólito; Cifre, Josep





The purpose of this study was to investigate the relationship between physiological, anthropometric, strength, and muscle power variables and a 5 km time trial (5kmT) in young runners. Twenty-three runners volunteered to participate in this study. Height, body mass (BM), body fat (BF), and fat-free mass (FFM) were measured. The subjects underwent laboratory testing to determine maximal oxygen uptake (VO2max), velocity at ventilatory threshold (VVT), running economy (RE), velocity associated with maximal oxygen uptake (vVO2max), and peak velocity (PV). Peak torque (PT), total work (TW), and power (PW) were measured by an isokinetic dynamometer at 60°·s and 240° s angular velocities. Right and left knee flexor and extensor torques were evaluated. Finally, the participants performed a 5kmT. Multiple regression and correlation analysis were used to determine the variables that significantly related to 5kmT. Strength and muscle power variables did not correlate with 5kmT. On the other hand, most physiological variables were associated with 5kmT. VVT alone explains 40% of the variance in 5kmT. The addition of the RE at speed 11.2 km.h (RE11.2) and FFM to the prediction equation allowed for 71% of the adjusted variance in 5kmT to be predicted. These results show that strength and muscle power variables are not good predictors of 5kmT; however, the physiological variables presented high prediction capacity in the 5kmT. Moreover, the anthropometric measures showed significant influence in performance prediction. PMID:25474331

Dellagrana, Rodolfo A; Guglielmo, Luiz Guilherme A; Santos, Bruno V; Hernandez, Sara G; Silva, SÉrgio G; Campos, Wagner DE



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


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



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

E-print Network

Characteristics of ocean waters reaching Greenland's glaciers Fiammetta STRANEO,1 David A, Eugene, OR, USA 3 Center for Atmosphere­Ocean Science, New York University, New York, NY, USA 4 Climate Change Institute, University of Maine, Orono, ME, USA 5 Department of Earth Sciences, University

Johnson, Helen


Ammonia pollution characteristics of centralized drinking water sources in China.  


The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources. PMID:23520842

Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming



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)



Physiological characteristics of Thiomicrospira sp. strain L-12 isolated from deep-sea hydrothermal vents  

SciTech Connect

Growth of the obligately chemolithotrophic Thiomicrospira sp. strain L-12, isolated from a hydrothermal vent at a depth of 2,550 m in the Galapagos Rift region, was optimal at pH 8 and required 200 mM Na/sup +/ and divalent ions (Ca/sup 2 +/ and Mg/sup 2 +/). The organism was microaerophilic and tolerated 300 sulfide without a decrease in the rate of CO/sub 2/ incorporation. Growth and CO/sub 2/ incorporation occurred within the temperature range of 10 to 35/sup 0/C, with both optimal at 25/sup 0/C. At the in situ pressure of 250 atm, the rate of CO/sub 2/ incorporation was reduced by 25% relative to that measured at 1 atm; it was entirely suppressed at 500 atm. The results of this physiological characterization suggest that Thiomicrospira sp. strain L-12 can be an active autotroph in the hydrothermal environment.

Ruby, E.G.; Jannasch, H.W.



Physiological and Molecular Characteristics of Elicitin- lnduced Systemic Acquired Resistance in Tobacco  

Microsoft Academic Search

Elicitins are low molecular weight proteins secreted by all Phy- fophfhora species analyzed so far. Application of the purified pro- teins to tobacco Nicotiana tabacum leads to the induction of resis- tance to subsequent inoculations with the black shank-causing agent, Phyfophfhora parasitica var nicofianae. In this paper, we describe the systemic characteristics of elicitin-induced acquired resistance in tobacco. Elicitin application

Harald Keller; Jean-Pierre Blein; Philippe Bonnet; Pierre Ricci


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.



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

NASA Astrophysics Data System (ADS)

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

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



Development of physiologically based toxicokinetic models for improving the human indoor exposure assessment to water contaminants: trichloroethylene and trihalomethanes.  


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 (PBTK) models for trihalomethanes (THM) and trichloroethylene (TCE) that will facilitate (1) the estimation of internal exposure to these chemicals for various multimedia indoor exposure scenarios, and (2) consideration of the impact of biological variability in the estimation of internal doses. Five PBTK models describing absorption through ingestion, inhalation and skin were developed for these contaminants. Their concentrations in ambient air were estimated from their respective tap water concentrations and their physicochemical characteristics. Algebraic descriptions of the physiological parameters, varying as a function of age, gender and diverse anthropometric parameters, allow the prediction of the influence of interindividual variations on absorbed dose and internal dosimetry. Simulations for various scenarios were done for a typical human (i.e., 70 kg, 1.7 m) as well as for humans of both genders varying in age from 1 to 90 years. Simulations show that ingestion contributes to less than 50% of the total absorbed dose or metabolized dose for all chemicals. This contribution to internal dosimetry, such as maximal venous blood concentrations (Cmax) and the area under the venous blood concentration time curve (AUC), decreases markedly (e.g., as low as 0.9% of Cmax for bromodichloromethane). The importance of this contribution varies mainly as a function of shower duration. Moreover, model simulations indicate that multimedia exposure is more elevated in children than adults (i.e., up to 200% of the adult internal dose). The models developed in this study allow characterization of the influence of the different routes of exposure and an improved estimation of the realistic multimedia exposure to volatile organic chemicals present in drinking water. Hence, such models will greatly improve health risk assessment for these chemicals. PMID:17060096

Haddad, Sami; Tardif, Ginette-Charest; Tardif, Robert



Infrared spectroscopy of sulfuric acid/water aerosols: Freezing characteristics  

NASA Astrophysics Data System (ADS)

A low-temperature flow cell has been used in conjunction with a Fourier transform infrared (FT-IR) spectrometer to study sulfuric acid/water aerosols. The aerosols were generated with a wide range of composition (28 to 85 wt%), including those characteristic of stratospheric sulfate aerosols, and studied over the temperature range from 240 K to 160 K. The particles exhibited deep supercooling, by as much as 100 K below the freezing point in some cases. Freezing of water ice was observed in the more dilute (<40 wt% sulfuric acid) particles, in agreement with the predictions of Jensen et al. and recent observations by Bertram et al. In contrast with theoretical predictions, however, the entire particle often does not immediately freeze, at least on the timescale of the present experiments (seconds to minutes). Freezing of the entire particle is observed at lower temperatures, well below that characteristic of the polar stratosphere.

Clapp, M. L.; Niedziela, R. F.; Richwine, L. J.; Dransfield, T.; Miller, R. E.; Worsnop, D. R.



Morphological and physiological species-dependent characteristics of the rodent Grueneberg ganglion  

PubMed Central

In the mouse, the Grueneberg ganglion (GG) is an olfactory subsystem implicated both in chemo- and thermo-sensing. It is specifically involved in the recognition of volatile danger cues such as alarm pheromones and structurally-related predator scents. No evidence for these GG sensory functions has been reported yet in other rodent species. In this study, we used a combination of histological and physiological techniques to verify the presence of a GG and investigate its function in the rat, hamster, and gerbil comparing with the mouse. By scanning electron microscopy (SEM) and transmitted electron microscopy (TEM), we found isolated or groups of large GG cells of different shapes that in spite of their gross anatomical similarities, display important structural differences between species. We performed a comparative and morphological study focusing on the conserved olfactory features of these cells. We found fine ciliary processes, mostly wrapped in ensheating glial cells, in variable number of clusters deeply invaginated in the neuronal soma. Interestingly, the glial wrapping, the amount of microtubules and their distribution in the ciliary processes were different between rodents. Using immunohistochemistry, we were able to detect the expression of known GG proteins, such as the membrane guanylyl cyclase G and the cyclic nucleotide-gated channel A3. Both the expression and the subcellular localization of these signaling proteins were found to be species-dependent. Calcium imaging experiments on acute tissue slice preparations from rodent GG demonstrated that the chemo- and thermo-evoked neuronal responses were different between species. Thus, GG neurons from mice and rats displayed both chemo- and thermo-sensing, while hamsters and gerbils showed profound differences in their sensitivities. We suggest that the integrative comparison between the structural morphologies, the sensory properties, and the ethological contexts supports species-dependent GG features prompted by the environmental pressure. PMID:25221478

Brechbühl, Julien; Klaey, Magali; Moine, Fabian; Bovay, Esther; Hurni, Nicolas; Nenniger-Tosato, Monique; Broillet, Marie-Christine



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


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



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


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 B(12) 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. PMID:22820007

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



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



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


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



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

PubMed Central

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

Maeshima, Masayoshi



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


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

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



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

PubMed Central

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

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



Brewster Angle Microscopy Study of Model Lung Surfactant Systems at the Air-Water and Air-Physiological Buffer Interfaces  

E-print Network

Brewster Angle Microscopy Study of Model Lung Surfactant Systems at the Air-Water and Air. Olesik #12;Copyright by Hardy Zingalaoa Castada 2010 #12;ii ABSTRACT The lungs have the ability to function normally due to its physiological and molecular components. In the lungs, air is delivered



EPA Science Inventory

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


[Effects of simulated acid rain on oilseed rape (Brassica napus) physiological characteristics at flowering stage and yield].  


A pot experiment was conducted to study the effects of different acidity simulated acid rain on the physiological characteristics at flowering stage and yield of oilseed rape (B. napus cv. Qinyou 9). Comparing with the control (pH 6.0), weak acidity (pH = 4.0-5.0) simulated acid rain stimulated the rape growth to some extent, but had less effects on the plant biomass, leaf chlorophyll content, photosynthetic characteristics, and yield. With the further increase of acid rain acidity, the plant biomass, leaf chlorophyll content, photosynthetic rate, antioxidative enzyme activities, and non-enzyme antioxidant contents all decreased gradually, while the leaf malonyldialdehyde (MDA) content and relative conductivity increased significantly. As the results, the pod number per plant, seed number per pod, seed weight, and actual yield decreased. However, different yield components showed different sensitivity to simulated acid rain. With the increasing acidity of simulated acid rain, the pod number per plant and the seed number per pod decreased significantly, while the seed weight was less affected. PMID:21043116

Cao, Chun-Xin; Zhou, Qin; Han, Liang-Liang; Zhang, Pei; Jiang, Hai-Dong



Anatomical and physiologic characteristics to predict football ability. Report of study methods and correlations, University of Arkansas, 1976.  


In a prospective study of 56 scholarship players at the University of Arkansas in 1976, 14 anatomical and physiologic measurements were carried out on each of the 56 players, to include certain orthopaedic strength, power, and balance tests, and compared to the coaches' subjective ratings of football ability in an effort to determine which characteristics best correlate to the athlete's true performance. The correlation matrix for the criterion measure and the predictor variables of selected anatomical strength, balance, and power measures are presented, and the results of the study indicate that genu varum (0.445) and tibial torsion (-0.33) had the highest correlation with the coaching criterion variable. The average tibial torsion was 42.6 for these scholarship athletes, while normal average tibial torsion among a nonscholarship group was 27.40 degrees. Other anatomical characteristics measured, as well as strength and power measure, could not reach the critical level of +/- 0.263 to be significant at the 0.05 level, although horsepower was close (0.255). The Margaria-Kalamen power test was significantly related to the 40-yard dash, and a moderately good measure of football ability. PMID:7361976

Arnold, J A; Brown, B; Micheli, R P; Coker, T P



Behavioral, attitudinal, and physiologic characteristics of smoking and nonsmoking asbestos-exposed shipyard workers  

SciTech Connect

The smoking characteristics of shipyard workers participating in an Asbestos Medical Surveillance Program (N=3991) were assessed. Sources of data were: 1) a self-assessment questionnaire on the smoking history and respiratory symptomatology of the 871 current smokers who participated in the smoking study, and 2) chest roentgenograms and pulmonary function test results and medical records for the entire population. The study population included 1711 current smokers, 988 former smokers and 1292 never smokers. The annual ''quit rate'' for former smokers had increased from less than 1% in 1961 to 4.2% in 1978. Of the 871 current smokers who participated in the smoking study, 19% had resumed smoking after having given up cigarettes for one year or longer. Men in the smoking study were reasonably well informed about the health consequences of smoking. While they perceived themselves to be susceptible to disease, and the disease to be serious, the benefits they saw in quitting were related more to economics and aesthetics than to health. When the results were age adjusted, no differences in rate of pulonary function abnormalities and chest film abnormalities were found betwen current smokers who voluntarily participated in the smoking study and those who did not. All pulmonary function testing abnormality and chest film abnormality rates were significantly lower for former smokers and never smokers.

Li, V.C.; Kim, Y.J.; Terry, P.B.; Cuthie, J.C.; Roter, D.; Emmett, E.A.; Harvey, A.; Permutt, S.



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.



Absorption characteristics of optically complex inland waters: Implications for water optical classification  

NASA Astrophysics Data System (ADS)

Multiple bio-optical measurements were conducted in inland waters of China, including Lake Taihu [spring and autumn], Lake Chaohu, Lake Dianchi, and Three Gorges Reservoirs. The variations in the absorption characteristics of chromophoric dissolved organic matter (CDOM), phytoplankton, and non-algal particles (NAP) and their relative contributions to total absorption among these waters were analyzed. The obtained results indicated that these areas are representative of the optically complex inland waters characterized by strong regional variations of their absorption properties. By means of the relative contributions of NAP and phytoplankton to the total water absorption at 550 and 675 nm, these waters were classified into three optical water types, each one having specific biogeochemical and optical properties. Two of the types were distinct and corresponded to waters that are optically controlled by NAP (Type I) and dominated by phytoplankton (Type III). Type II was related to relatively optically mixed waters where the absorption properties are controlled by NAP and phytoplankton. Additionally, the differences in remote-sensing reflectance (Rrs) spectra among the three classified water types were clarified to establish optical criteria for identifying these water types. On this basis, the classification criteria for MERIS images were developed, which allowed one to cluster every Rrs spectrum into one of the three water types by comparing the values from band 6, band 8, and band 9 of MERIS images. The proposed criteria were subsequently conducted to map the water types of Lake Taihu using MERIS images.

Shi, Kun; Li, Yunmei; Li, Lin; Lu, Heng



Characteristic mega-basin water storage behavior using GRACE.  


[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 km(2)), 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



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


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

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



Influence of simulated warming using OTC on physiological–biochemical characteristics of Elymus nutans in alpine meadow on Qinghai-Tibetan plateau  

Microsoft Academic Search

Elymus nutans Griseb. is a typical important plant species in the alpine meadow of Qinghai-Tibetan plateau. To examine the effects of temperature elevation on its physiological and chemical characteristics, a simulation study was conducted in situ with open-top chambers (OTC) followed the method of International Tundra Experiment (ITEX) from November 2002 to September 2007, and these OTCs were designed five

Fei Ren; Hua-kun Zhou; Xin-Quan Zhao; Fa Han; Li-Na Shi; Ji-Chuang Duan; Jian-Zhong Zhao



Relationship between characteristics of water polo players and efficacy indices.  


The aim of this study was to define and examine the relationships between the anthropometrical characteristics, maximum isometric grip strength, and competition throwing velocities and efficacy indices in high-level water polo player. Eleven elite trained male water polo players participated in this study. During preseason training, the following measures were taken: standard anthropometry (height, body mass, arm spam, skinfolds, body girths, and skeletal breadths) and grip strength. During official European Competitions (n = 7), efficacy indices (offensives: shot definition, resolution, precision, blocked and defensives: shot resolution when defending and shots stopped when defending), average and maximum throwing velocities from all the participants by zones and in some offensive tactical phases (even, counterattacks and power play) were also determined. Throwing velocities were different (p ? 0.05) between some of the offensive tactical phases (even = 17.9 ± 2.4 vs. power play = 16.7 ± 2.6 m·s(-1)). In addition, significant correlations were found between competitive throwing velocities and different offensive efficacy indices. We concluded that there were significant correlations between conditioning and performance variables with anthropometrical characteristics and offensive tactical indices (blocked shots received and shot precision). Coaches should pay attention to these indices for the development of performance throughout the season. PMID:22728942

Alcaraz, Pedro E; Abraldes, J Arturo; Ferragut, Carmen; Vila, Helena; Rodríguez, Nuria; Argudo, Francisco M



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


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



Water relation characteristics of Calligonum and consequences for a sustainable management of vegetation in the southern fringe of Takelamakan Desert  

NASA Astrophysics Data System (ADS)

On field sites, water physiological characteristics of the desert legume Calligonum were investigated during the vegetation period in 1999(2000) in the southern fringe of the Takelamakan Desert, Xinjiang, NW China. The seasonal variation of predawn water potentials and of diurnal water potential indicated that Calligonum plants were well water supplied and it has stronger ability to maintain the water balance within the body over the entire vegetation period. Water relationship parameters from pressure-volume analysis confirmed that Calligonum plants were not drought stressed and xylem sap flow measurements further indicated that Calligonum plants were well water supplied during the summer months. The data indicate that artificial flooding only had limited effects on the water relations of plant. Long-term adjustment to the hyper-arid environment and its growth (survival) of Calligonum maybe is dependent on permanent contact with ground water. Therefore, it is important that variations of ground water depth are kept to a minimum. The study will provide theoretical basis for the restoration and management of natural vegetation in arid and semi-arid regions.

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



Physiological characteristics of National Collegiate Athletic Association Division I ice hockey players and their relation to game performance.  


Previous ice hockey research has focused on physiological profiles and determinants of skating speed, but few studies have examined the association of preseason player evaluations with a measure of season-long performance. Understanding which tests are most predictive of player performance could help coaches organize practice and training more effectively. The purpose of this study was to describe physical characteristics and skill levels of 24 members of an NCAA Division I men's ice hockey team and relate them to game performance over the course of a season as measured by plus/minus (+/-) score. Subjects performed a battery of preseason tests including treadmill maximal aerobic capacity, body fat, leg press, push-ups, bench press, chin-ups, and sprinting ability both on and off ice. Pearson and Spearman correlations were used to examine correlations between preseason measures and +/- score. One coach also subjectively grouped the top and bottom 6 players, and analysis of variance was used to examine any differences in preseason measures and +/- score between these 2 groups. Leg press, chin-ups, bench press, and repeat sprint performance were significantly correlated with +/- score (r = 0.554, 0.462, 0.499, and -0.568, respectively). Teams with limited time and resources may choose to perform these tests to evaluate player potential efficiently. Only +/- score differed between top and bottom players suggesting that +/- accurately reflected the coach's perception of player success in this sample. PMID:21478763

Peyer, Karissa L; Pivarnik, James M; Eisenmann, Joey C; Vorkapich, Michael



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)



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



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



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

E-print Network

EFFECTS OF DENSITY AND WATER AVAILABILITY ON THE BEHAVIOR, PHYSIOLOGY, AND WEIGHT LOSS OF SLAUGHTER HORSES DURING TRANSPORT A Thesis by CHRISTA MARIE IACONO Submitted to the Office of Graduate Studies of Texas A&M University... DURING TRANSPORT A Thesis by CHRISTA MARIE IACONO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee...

Iacono, Christa Marie



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.


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

PubMed Central

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

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



The Characteristics of Sleepiness During Real Driving at Night—A Study of Driving Performance, Physiology and Subjective Experience  

PubMed Central

Study Objectives: Most studies of sleepy driving have been carried out in driving simulators. A few studies of real driving are available, but these have used only a few sleepiness indicators. The purpose of the present study was to characterize sleepiness in several indicators during real driving at night, compared with daytime driving. Design: Participants drove 55 km (at 90km/h) on a 9-m-wide rural highway in southern Sweden. Daytime driving started at 09:00 or 11:00 (2 groups) and night driving at 01:00 or 03:00 (balanced design). Setting: Instrumented car on a real road in normal traffic. Participants: Eighteen participants drawn from the local driving license register. Interventions: Daytime and nighttime drives. Measurement and Results: The vehicle was an instrumented car with video monitoring of the edge of the road and recording of the lateral position and speed. Electroencephalography and electrooculography were recorded, together with ratings of sleepiness every 5 minutes. Pronounced effects of night driving were seen for subjective sleepiness, electroencephalographic indicators of sleepiness, blink duration, and speed. Also, time on task showed significant effects for subjective sleepiness, blink duration, lane position, and speed. Sleepiness was highest toward the end of the nighttime drive. Night driving caused a leftward shift in lateral position and a reduction of speed. The latter two findings, as well as the overall pattern of sleepiness indicators, provide new insights into the effects of night driving. Conclusion: Night driving is associated with high levels of subjective, electrophysiologic, and behavioral sleepiness. Citation: Sandberg D; Anund A; Fors C; Kecklund G; Karlsson JG; Wahde M; Åkerstedt T. The characteristics of sleepiness during real driving at night—a study of driving performance, physiology and subjective experience. SLEEP 2011;34(10):1317-1325. PMID:21966063

Sandberg, David; Anund, Anna; Fors, Carina; Kecklund, Göran; Karlsson, Johan G.; Wahde, Mattias; Åkerstedt, Torbjörn



[Complex effects of simulated acid rain and Cu on the physiological characteristics of Paulownia fortunei and its detoxification mechanism].  


A pot experiment was conducted to study the effects of simulated acid rain (pH 4.0, 5.0) and Cu (0-200 mg x kg(-1)) on the physiological characteristics of Paulownia fortunei and its detoxification mechanism. With no Cu addition, the leaf chlorophyll, carotenoid, O2 division by, H2O2, and MDA contents of P. fortunei had no significant differences between the two acid rain treatments. However, with the addition of 100 and 200 mg Cu x kg(-1), the chlorophyll and carotenoid contents of treatment pH 4.0 were lower, while the O2 divided by, H2O2 and MDA contents were higher thanthose of treatment pH 5.0. The chlorophyll a/b ratio of treatments Cu was higher than that of the control. The leaf Cu content decreased obviously with the increasing acidity of stimulated acid rain, but the root Cu content was in reverse. With increasing Cu addition, both the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the total contents of phytochelatins (PCs) and glutathione (GSH) in treatment pH 5.0 increased, while the activities of SOD, POD, CAT and APX in treatment pH 4.0 decreased after an initial increase, and the total contents of glutathione (GSH) decreased greatly in treatment 200 mg Cu x kg(-1). All of these demonstrated that the oxidative stress of high Cu concentration to P. fortunei was aggravated by stimulated acid rain. PMID:20560310

Wang, Jiang; Zhang, Chong-Bang; Ke, Shi-Sheng; Qian, Bao-Ying



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


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



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



Life under water: physiological adaptations to diving and living at sea.  


This review covers the field of diving physiology by following a chronological approach and focusing heavily on marine mammals. Because the study of modern diving physiology can be traced almost entirely to the work of Laurence Irving in the 1930s, this particular field of physiology is different than most in that it did not derive from multiple laboratories working at many locations or on different aspects of a similar problem. Because most of the physiology principles still used today were first formulated by Irving, it is important to the study of this field that the sequence of thought is examined as a progression of theory. The review covers the field in roughly decadal blocks and traces ideas as they were first suggested, tested, modified and in some cases, abandoned. Because diving physiology has also been extremely dependent on new technologies used in the development of diving recorders, a chronological approach fits well with advances in electronics and mechanical innovation. There are many species that dive underwater as part of their natural behavior, but it is mainly the marine mammals (seals, sea lions, and whales) that demonstrate both long duration and dives to great depth. There have been many studies on other diving species including birds, snakes, small aquatic mammals, and humans. This work examines these other diving species as appropriate and a listing of reviews and relevant literature on these groups is included at the end. PMID:23723028

Castellini, Michael



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 and Polar Surface Water characteristics in the East Greenland Current during the AO-02 Oden expedition to the journal pertain. #12;ACCEPTED MANUSCRIPT Liquid freshwater transport and Polar Surface Water

Nilsson, Johan


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

E-print Network

in the laboratory. Birds were provided with P. atlantica fruit and mealworms, and had either free access to water (controls) or were water- deprived. In experiment 1, in which mealworm avail- ability was restricted, water, in which mealworms were provided ad libitum, water availability influenced the birds' diet: water

Nathan, Ran


Physiology and transcriptomics of water-deficit stress responses in wheat cultivars TAM 111 and TAM 112.  


Hard red winter wheat crops on the U.S. Southern Great Plains often experience moderate to severe drought stress, especially during the grain filling stage, resulting in significant yield losses. Cultivars TAM 111 and TAM 112 are widely cultivated in the region, share parentage and showed superior but distinct adaption mechanisms under water-deficit (WD) conditions. Nevertheless, the physiological and molecular basis of their adaptation remains unknown. A greenhouse study was conducted to understand the differences in the physiological and transcriptomic responses of TAM 111 and TAM 112 to WD stress. Whole-plant data indicated that TAM 112 used more water, produced more biomass and grain yield under WD compared to TAM 111. Leaf-level data at the grain filling stage indicated that TAM 112 had elevated abscisic acid (ABA) content and reduced stomatal conductance and photosynthesis as compared to TAM 111. Sustained WD during the grain filling stage also resulted in greater flag leaf transcriptome changes in TAM 112 than TAM 111. Transcripts associated with photosynthesis, carbohydrate metabolism, phytohormone metabolism, and other dehydration responses were uniquely regulated between cultivars. These results suggested a differential role for ABA in regulating physiological and transcriptomic changes associated with WD stress and potential involvement in the superior adaptation and yield of TAM 112. PMID:25014264

Reddy, Srirama Krishna; Liu, Shuyu; Rudd, Jackie C; Xue, Qingwu; Payton, Paxton; Finlayson, Scott A; Mahan, James; Akhunova, Alina; Holalu, Srinidhi V; Lu, Nanyan



Water-Landing Characteristics of a Reentry Capsule  

NASA Technical Reports Server (NTRS)

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

McGehee, John R.; Hathaway, Melvin E.; Vaughan, Victor L., Jr.



The Epiphytic Fern Elaphoglossum luridum (Fée) 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, Áurea Maria



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


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



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

E-print Network

). We used these techniques to test whether interspecific differences in components of water balance areThe subject of water balance has been central to insect physiology for over a century. The high balance. For example, one might expect desert arthropods to be highly tolerant of water loss, relative

Ahmad, Sajjad


Physiological responses of pear thrips-damaged sugar maples to light and water stress  

Microsoft Academic Search

Summary We assessed the effect of feeding damage by pear thrips, Tueniothrips inconsequens Uzel (Thysanoptera: Thripidae), on gas exchange and water relations of sugar maple (Acer saccharum Marsh.) seedlings. Compared to undamaged seedlings, feeding punctures in the leaf epidermis of thrips-damaged seedlings decreased water use efficiency, increased leaf conductance to water vapor, and decreased predawn water potential. Under conditions of



Saline water irrigation effects on soil salinity distribution and some physiological responses of field grown Chemlali olive.  


The shortage of water resources of good quality is becoming an issue in arid and semi arid regions. Per consequent, the use of water resources of marginal quality is becoming an important consideration, particularly in arid regions in Tunisia, where large quantities of saline water are used for irrigation. Nevertheless, the use of these waters in irrigated lands requires the control of soil salinity and a comprehensive analysis even beyond the area where water is applied. The aim of this study was to investigate the effects of saline water irrigation on soil salinity distribution and some physiological traits of field-grown adult olive trees (Olea europaea L. cv. Chemlali) under contrasting environmental conditions of the arid region in the south of Tunisia. The plants were subjected, over two growing seasons, to two drip irrigated treatments: fresh water (ECe=1.2 dS m(-1), FW) and saline water (ECe=7.5 dS m(-1), SW). Saline water irrigation (SW) has led to a significant increase in soil salinity. Furthermore, these results showed that soil salinity and soil moisture variations are not only dependent on water salinity level but are also controlled by a multitude of factors particularly the soil texture, the distance from the irrigation source and climatic conditions (rainfall pattern, temperature average, …). On the other hand, salt treatment reduced leaf midday water potential (LMWP), relative water content and photosynthetic activity and increased the leaf proline content, and this increase was season-dependent. Indeed, LMWP in SW plants decreased to -3.71 MPa. Furthermore, the highest level of proline in SW plants was registered during summer period (2.19 ?mol/mg Fw). The proline accumulation recorded in stressed plants has allowed them to preserve appropriate leaf water status and photosynthetic activity. More to the point, this olive cultivar seems to be more sensible to soil salinity during the intense growth phase. Such tendencies would help to better manage water resources for irrigation, particularly under actual climatic conditions of water scarcity. For example, in the case of the availability of different water qualities, it would be better to preserve those of high quality for olive irrigation during the intense vegetative growth phase, in coincidence with high salt sensitive period, and those of low quality for irrigation during partial growth and plant rest phases. What's more, the urgent use of saline water for irrigation should not be applied without taking into consideration the different surroundings conditions where it is used, particularly the water salinity level, the soil type, the adopted irrigation system, the degree of the crop salt tolerance, the plant growth phase and the climatic conditions of the experimental site. PMID:22572465

Ben Ahmed, Chedlia; Magdich, Salwa; Ben Rouina, Bechir; Boukhris, Makki; Ben Abdullah, Ferjani



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


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

Zhang, Ling-Ling; Wen, Da-Zhi



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

E-print Network

to fresh water were quantified. Salt-water adapted turtles were exposed to fresh water for 4 d before being in sea turtles may be adrenocortically mediated. In another group of marine adapted reptiles, sea snakes exposure on water flux rates and osmotic responses in Kemp's ridley sea turtles (Lepidochelys kempi ) Rudy

Ortiz, Rudy M.


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)



Physiological responses of pear thrips-damaged sugar maples to light and water stress.  


We assessed the effect of feeding damage by pear thrips, Taeniothrips inconsequens Uzel (Thysanoptera:Thripidae), on gas exchange and water relations of sugar maple (Acer saccharum Marsh.) seedlings. Compared to undamaged seedlings, feeding punctures in the leaf epidermis of thrips-damaged seedlings decreased water use efficiency, increased leaf conductance to water vapor, and decreased predawn water potential. Under conditions of high soil water and high light intensity, carbon dioxide exchange rate (CER) was greater for thrips-damaged than undamaged seedlings because of greater CO(2) conductance through feeding punctures. Under conditions of low soil water, CER was lower for thrips-damaged than undamaged seedlings as a result of water stress. Carbon dioxide exchange rate at low light and low soil water was limited by non-stomatal factors, but no difference in non-stomatal limitation to CER was detected between thrips-damaged and undamaged seedlings. Leaf tissue water relations differed between thrips-damaged and undamaged seedlings and under high and low soil water conditions. The results suggest that the reduction in leaf area of thrips-damaged seedlings can be partially compensated by elevated CER under conditions of high light intensity and high soil water. However, high gas exchange rates through feeding punctures predisposes thrips-damaged seedlings to water stress that can reduce CER under conditions of low soil water. PMID:14972850

Kolb, T E; McCormick, L H; Shumway, D L



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

PubMed Central

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



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


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



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



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

Microsoft Academic Search

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

Zhao Yang; Haibo Zhao; Xihong Li



Thermophysical characteristics of water-in-FC72 nanoemulsion fluids  

NASA Astrophysics Data System (ADS)

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

Han, Z. H.; Yang, B.



Dynamic voltage-current characteristics for a water jet plasma arc  

SciTech Connect

A virtual instrument technology is used to measure arc current, arc voltage, dynamic V-I characteristics, and nonlinear conductance for a cone-shaped water jet plasma arc under ac voltage. Experimental results show that ac arc discharge mainly happens in water vapor evaporated from water when heated. However, due to water's cooling effect and its conductance, arc conductance, reignition voltage, extinguish voltage, and current zero time are very different from those for ac arc discharge in gas work fluid. These can be valuable to further studies on mechanism and characteristics of plasma ac discharge in water, and even in gas work fluid.

Yang Jiaxiang; Lan Sheng; Xu Zuoming [College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, Heilongjiang 150040 (China)



Dynamic voltage-current characteristics for a water jet plasma arc  

NASA Astrophysics Data System (ADS)

A virtual instrument technology is used to measure arc current, arc voltage, dynamic V-I characteristics, and nonlinear conductance for a cone-shaped water jet plasma arc under ac voltage. Experimental results show that ac arc discharge mainly happens in water vapor evaporated from water when heated. However, due to water's cooling effect and its conductance, arc conductance, reignition voltage, extinguish voltage, and current zero time are very different from those for ac arc discharge in gas work fluid. These can be valuable to further studies on mechanism and characteristics of plasma ac discharge in water, and even in gas work fluid.

Yang, Jiaxiang; Lan, Sheng; Xu, Zuoming



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

NASA Astrophysics Data System (ADS)

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

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



Impact of Soil Type and Compaction Conditions on Soil Water Characteristic  

E-print Network

Impact of Soil Type and Compaction Conditions on Soil Water Characteristic C. J. Miller, M.ASCE1 the variation of water content and pore water suction for compacted clayey soils. The soils had varying amounts of clay fraction with plasticities ranging from low to high plasticity. The unsaturated soil behavior

Yu, Sheng-Tao


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


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



Evaluation of a computer program used to estimate water characteristic curve  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soil water characteristic curve, h(theta), can be used to estimate a variety of parameters in unsaturated soils. One practical application of h(theta) is its use by DRAINMOD, a drainage model that has been widely used in shallow water table regions, to determine the water table depth–drainage v...


Biomechanical characteristics of adults walking in shallow water and on land  

Microsoft Academic Search

Although water environment has been employed for different physical activities, there is little available information regarding the biomechanical characteristics of walking in shallow water. In the present study, we investigated the kinematics, ground reaction forces (GRF), and electromyographic (EMG) activation patterns of eight selected muscles of adults walking in shallow water and on land. Ten healthy adults were videotaped while

Ana M. F. Barela; Sandro F. Stolf; Marcos Duarte



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


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


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



Polyols in grape berry: transport and metabolic adjustments as a physiological strategy for water-deficit stress tolerance in grapevine.  


Polyols are important metabolites that often function as carbon and energy sources and/or osmoprotective solutes in some plants. In grapevine, and in the grape berry in particular, the molecular aspects of polyol transport and metabolism and their physiological relevance are virtually unknown to date. Here, the biochemical function of a grapevine fruit mesocarp polyol transporter (VvPLT1) was characterized after its heterologous expression in yeast. This H(+)-dependent plasma membrane carrier transports mannitol (K m=5.4mM) and sorbitol (K m=9.5mM) over a broad range of polyols and monosaccharides. Water-deficit stress triggered an increase in the expression of VvPLT1 at the fully mature stage, allowing increased polyol uptake into pulp cells. Plant polyol dehydrogenases are oxireductases that reversibly oxidize polyols into monosaccharides. Mannitol catabolism in grape cells (K m=30.1mM mannitol) and mature berry mesocarps (K m=79mM) was, like sorbitol dehydrogenase activity, strongly inhibited (50-75%) by water-deficit stress. Simultaneously, fructose reduction into polyols via mannitol and sorbitol dehydrogenases was stimulated, contributing to their higher intracellular concentrations in water-deficit stress. Accordingly, the concentrations of mannitol, sorbitol, galactinol, myo-inositol, and dulcitol were significantly higher in berry mesocarps from water-deficit-stressed Tempranillo grapevines. Metabolomic profiling of the berry pulp by GC-TOF-MS also revealed many other changes in its composition induced by water deficit. The impact of polyols on grape berry composition and plant response to water deficit stress, via modifications in polyol transport and metabolism, was analysed by integrating metabolomics with transcriptional analysis and biochemical approaches. PMID:25433029

Conde, Artur; Regalado, Ana; Rodrigues, Diana; Costa, J Miguel; Blumwald, Eduardo; Chaves, M Manuela; Gerós, Hernâni




EPA Science Inventory

Heterotrophic bacteria isolated from drinking water distribution systems were examined to determine if they possessed putative virulence factors such as hemolysins, proteases, or cytotoxins. Representative samples of colonies from several different distribution systems indicated ...



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...



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...


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

NASA Astrophysics Data System (ADS)

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

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



Environmental Physiology of the Mangrove Rivulus, Kryptolebias marmoratus, A Cutaneously Breathing Fish That Survives for Weeks Out of Water  

PubMed Central

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 H2O across skin that contains a rich population of ionocytes. Ammonia excretion occurs in part by cutaneous NH3 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.



Physiological and molecular mechanisms of salt and water homeostasis in the nematode Caenorhabditis elegans.  


Intracellular salt and water homeostasis is essential for all cellular life. Extracellular salt and water homeostasis is also important for multicellular organisms. Many fundamental mechanisms of compensation for osmotic perturbations are well defined and conserved. Alternatively, molecular mechanisms of detecting salt and water imbalances and regulating compensatory responses are generally poorly defined for animals. Throughout the last century, researchers studying vertebrates and vertebrate cells made critical contributions to our understanding of osmoregulation, especially mechanisms of salt and water transport and organic osmolyte accumulation. Researchers have more recently started using invertebrate model organisms with defined genomes and well-established methods of genetic manipulation to begin defining the genes and integrated regulatory networks that respond to osmotic stress. The nematode Caenorhabditis elegans is well suited to these studies. Here, I introduce osmoregulatory mechanisms in this model, discuss experimental advantages and limitations, and review important findings. Key discoveries include defining genetic mechanisms of osmolarity sensing in neurons, identifying protein damage as a sensor and principle determinant of hypertonic stress resistance, and identification of a putative sensor for hypertonic stress associated with the extracellular matrix. Many of these processes and pathways are conserved and, therefore, provide new insights into salt and water homeostasis in other animals, including mammals. PMID:23739341

Choe, Keith P



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


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




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.




Using physiologically based pharmacokinetic models to estimate the health risk of mixtures of trihalomethanes from reclaimed water.  


To estimate the health risk of mixture of trihalomethanes (THMs) from reclaimed water during toilet flushing, the interaction-based Hazard Index (HIinteraction-based) and the mixture carcinogenic risk (CRM) according to tissue dose were conducted through the integrated use of both the exposure concentrations model and the physiologically based pharmacokinetic (PBPK) model of THMs. Monte Carlo simulations were employed to implement the probabilistic risk analysis and sensitivity analysis. Nine samples were analyzed, which were collected from J Water Reclamation Plant (JWRP) in Tianjin of China. The results indicated that the mean HIinteraction-based (=0.85) was lower than the acceptable risk level (=1). The probability that the HIinteraction-based exceeded the acceptable risk level is 22.97%. For carcinogenic risk, the CRM ranges from 9.41×10(-7) to 3.54×10(-5), with a mean of 5.49×10(-6). Moreover, the probability of exceeding the acceptable risk level (1×10(-6)) is near 100%. And the values of HIinteraction-based from sample no. 1, 5, and 7 exceeded 1, while the values of CRM for all samples exceeded 1×10(-6). Consequently, the reclaimed water used for flushing toilets should be paid more attention, though non-carcinogenic effect is relatively small. Furthermore, the concentrations of DBCM had greater impact on both the carcinogenic and non-carcinogenic risk based on sensitivity analysis. PMID:25497033

Niu, Zhiguang; Zang, Xue; Zhang, Ying



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.



Alcohol and dilution water characteristics in distilled anis (ouzo).  


The authenticity of some mixed drinks such as vodka or rum was correlated to the conductivity of the dilution water. Authentic drinks demonstrated low conductivity, suggesting the use of treated water, whereas fraud drinks were mixed with regular tap water. The objective of the present study was to test if this criterion is valid for distilled anis, also known as ouzo. Several Greek distilled anis samples, mostly ouzo samples, were tested for different parameters including conductivity, pH, and percentage of different alcohol constituents. Because ouzo in Greece is commonly produced by small enterprises, no correlation between conductivity and the size of the producer was possible. Neither was it possible to correlate the price or high consumption with conductivity and, thus, prior water treatment. Alcohol quality in terms of undesirable constituents, such as methanol content, was good and comparable among samples. In ouzo, water is related to the producer quality goal for the final product and, thus, it is treated and used accordingly. PMID:24816147

Karapanagioti, Hrissi K; Bekatorou, Argyro



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

Microsoft Academic Search

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

Shaozhong Kang; Jianhua Zhang



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

E-print Network

, and Academic Press, New York. Hanson AD, WD Hitz 1982 Metabolic responses of mesophytes to plant water deficits. Annu Rev Plant Physiol 33:163-203. Harris JA 1918 On the osmotic concentration of the tissue fluids of phanerogamic epiphytes. Am J Bot 5...

Nowak, Edward J.; Martin, Craig E.




Technology Transfer Automated Retrieval System (TEKTRAN)

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


Impact of water and feed deprivation on physiological parameters in steers  

Technology Transfer Automated Retrieval System (TEKTRAN)

A report in rats demonstrated that dehydration as the result of 8 d of water deprivation increased leakage of endotoxin from the intestine (Zurovsky and Barbiro, 2000 Experimental and toxicologic pathology 52:37-42). Given the large number of gram negative bacteria in the rumen of cattle, a much sho...



EPA Science Inventory

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


Quantifying succulence: a rapid, physiologically meaningful metric of plant water storagepce_2503 1533..1542  

E-print Network

1533..1542 R. MATTHEW OGBURN & ERIKA J. EDWARDS Department of Ecology and Evolutionary Biology, Brown cuticle (Gibson 1982; Ogburn & Edwards 2009), low stomatal density (Gibson & Nobel 1986) and crassulacean). The core feature of the succulence syndrome, however, is the ability of water storage tissues to support

Edwards, Erika J.


Physiology Online  

NSDL National Science Digital Library

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



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


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

Navas, Carlos A



Environmental impact of leachate characteristics on water quality.  


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



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.

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




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...



Microsoft Academic Search

This study investigated the effects of seawater on cavitation noise using a water jet test, a two-dimensional wing test, and a three-dimensional wing test. A model propeller cavitation test was conducted in a cavitation tunnel using seawater, in order to determine the effects of propeller cavitation more precisely. In the cavitation tests, measured propeller performance for both cavitation noise inception

Hikaru Kamiirisa



Technology Transfer Automated Retrieval System (TEKTRAN)

Public health concerns about pathogens present in animal manure are emerging constraints to water supplies in many areas of the world. The aim of this study was to examine microbial community composition in aquifer material in an effort to understanding key processes that control the growth and mobi...


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.



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

E-print Network

for collecting, preparing, shipping, packing, etc. samples at various times during the study. I want to thank Roldan Valverde in the Biology Department !TAMU) for assisting with the corticosterone assays. I am also indebted to Dr. Olav Oftedal and Mike Power... to deal with a marine environment for prolonged periods (Hill and Reynolds 1989, Maluf 1989). Trichechids, at one time, must have been adapted for dealing with salt water due to their marine origin. A review of the hormonal regulation of electrolyte...

Ortiz, Rudy Martin



Effects of larval growth condition and water availability on desiccation resistance and its physiological basis in adult Anopheles gambiae sensu stricto  

PubMed Central

Background Natural populations of the malaria mosquito Anopheles gambiae s.s. are exposed to large seasonal and daily fluctuations in relative humidity and temperature, which makes coping with drought a crucial aspect of their ecology. Methods To better understand natural variation in desiccation resistance in this species, the effects of variation in larval food availability and access to water as an adult on subsequent phenotypic quality and desiccation resistance of adult females of the Mopti chromosomal form were tested experimentally. Results It was found that, under normal conditions, larval food availability and adult access to water had only small direct effects on female wet mass, dry mass, and water, glycogen and body lipid contents corrected for body size. In contrast, when females subsequently faced a strong desiccation challenge, larval food availability and adult access to water had strong carry-over effects on most measured physiological and metabolic parameters, and affected female survival. Glycogen and water content were the most used physiological reserves in relative terms, but their usage significantly depended on female phenotypic quality. Adult access to water significantly influenced the use of water and body lipid reserves, which subsequently affected desiccation resistance. Conclusions These results demonstrate the importance of growth conditions and water availability on adult physiological status and subsequent resistance to desiccation. PMID:20691104



[Geothermal water as part of culture medium and morpho-physiological properties of Saccharomyces cerevisiae].  


Morphophysiological changes in Saccharomyces cerevisiae gamma-503 cells cultivated in nutrient media containing geothermal water as a source of mineral substances were studied. The optimal mineralization of the medium was found to be 4.0 g/l, supplemented with 2.6 g/l (NH4)2HPO4. These conditions provided active growth and development of the culture with high yields of the biomass and the maximal enzymatic activity. Differences in cellular structures at certain stages of metabolism were demonstrated. PMID:10496008

Abramov, Sh A; Kotenko, S Ts; Khalilova, E A; Kisrieva, Iu S



Physiological Reviews  

NSDL National Science Digital Library

_Physiological Reviews_is currently available online through the American Physiological Society. Online abstracts and full-text content begin January 1998. Physiological reviews is made available through Stanford University's HighWire Press.



Oral physiology and mastication.  


Mastication is a sensory-motor activity aimed at the preparation of food for swallowing. It is a complex process involving activities of the facial, the elevator and suprahyoidal muscles, and the tongue. These activities result in patterns of rhythmic mandibular movements, food manipulation and the crushing of food between the teeth. Saliva facilitates mastication, moistens the food particles, makes a bolus, and assists swallowing. The movement of the jaw, and thus the neuromuscular control of chewing, plays an important role in the comminution of the food. Characteristics of the food, e.g. water and fat percentage and hardness, are known to influence the masticatory process. Food hardness is sensed during mastication and affects masticatory force, jaw muscle activity, and mandibular jaw movements. When we chew for instance a crispy food, the jaw decelerates and accelerates as a result of resistance and breakage of food particles. The characteristic breakage behaviour of food is essential for the sensory sensation. This study presents a short review of the influence of oral physiology characteristics and food characteristics on the masticatory process. PMID:16564557

van der Bilt, A; Engelen, L; Pereira, L J; van der Glas, H W; Abbink, J H



Dipole receiver characteristics in the presence of sea water  

NASA Technical Reports Server (NTRS)

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

Kao, P. S.



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

Microsoft Academic Search

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

Metin Turan; Medine Gulluce; Fikrettin ?ahin



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

Microsoft Academic Search

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

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



Effects of rearing density and water current on the respiratory physiology and haematology in rainbow trout, Oncorhynchus mykiss at high temperature  

Microsoft Academic Search

Rearing fish at high densities is considered stressful. For many species this leads to poor feed conversion, decreased feed intake and reduced growth, possibly caused by a change in energy partitioning or expenditure. To test this theory, we examined how rearing density and water current affected the respiratory physiology during rest and exercise in rainbow trout. Trout were also subjected

Peter Vilhelm Skov; Bodil Katrine Larsen; Michael Frisk; Alfred Jokumsen



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.



Effect of temperature and chlorination of pre-washing water on shelf-life and physiological properties of ready-to-use iceberg lettuce  

Microsoft Academic Search

The effects of cold and warm, chlorinated water as well as warm water without chlorination for pre-washing trimmed, cored iceberg lettuce heads was assessed regarding the shelf-life and physiological properties of the resulting ready-to-use (RTU) produce. On a pilot-plant scale, lettuce heads were shredded with or without pre-washing (50 °C, no chlorine; 4 and 50 °C, 200 mg\\/l free chlorine;

Sascha Baur; Ralph Klaiber; Hua Wei; Walter Peter Hammes; Reinhold Carle



A recombinant polymeric hemoglobin with conformational, functional, and physiological characteristics of an in vivo O2 transporter.  


With the objective of developing a recombinant oxygen carrier suitable for therapeutic applications, we have employed an Escherichia coli expression system to synthesize in high-yield hemoglobin (Hb) Minotaur, containing alpha-human and beta-bovine chains. Polymerization of Hb Minotaur through S-S intermolecular cross-linking was obtained by introducing a Cys at position beta9 and substituting the naturally occurring Cys. This homogeneous polymer, Hb Polytaur, has a molecular mass of approximately 500 kDa and was resistant toward reducing agents present in blood. In mice, the circulating half-time (3 h) was fivefold greater than adult human Hb (HbA). The half-time of autooxidation measured in blood (46 h) exceeded the circulating retention time. Hypervolemic exchange transfusion resulted in increased arterial blood pressure similar to that with albumin. The increase in pressure was less than that obtained by transfusion of cross-linked tetrameric Hb known to undergo renovascular extravasation. The nitric oxide reactivity of Hb Polytaur was similar to HbA, suggesting that the diminished pressor response to Hb Polytaur was probably related to diminished extravasation. Transfusion of 3% Hb Polytaur during focal cerebral ischemia reduced infarct volume by 22%. Therefore, site-specific Cys insertion on the Hb surface results in uniform size polymers that do not produce the large pressor response seen with tetrameric Hb. Polymerization maintains physiologically relevant oxygen and heme affinity, stability toward denaturation and oxidation, and effective oxygen delivery as indicated by reduced cerebral ischemic damage. PMID:12689854

Bobofchak, Kevin M; Mito, Toshiaki; Texel, Sarah J; Bellelli, Andrea; Nemoto, Masaaki; Traystman, Richard J; Koehler, Raymond C; Brinigar, William S; Fronticelli, Clara



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

PubMed Central

Objective Although water heater manufacturers adopted a voluntary standard in the 1980’s to pre-set thermostats on new water heaters to 120°F, tap water scald burns cause an estimated 1,500 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. Methods 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. Results 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<0.01). 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 (OR=4.99; p<0.01). Water heaters with more gallons per person in the household were more likely to be at or below the recommended 120°F. Conclusions 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; Zhu, Jeffrey; Perry, Elise C.; Gielen, Andrea C.



Initiation, growth and plasma characteristics of ‘Gatchina’ water plasmoids  

NASA Astrophysics Data System (ADS)

Plasmoids generated by discharging a high-voltage capacitor through electrodes submerged in a weak aqueous electrolyte have attracted attention because of their resemblance to the natural phenomenon of ball lightning. We describe an extensive series of experimental studies which elucidate the mechanism responsible for the production of water plasmoids. We show that a plasma jet from a cathode spot is responsible for the formation of the main plasmoid, which grows in accordance with a current surge due to increasing contact area of the plasma with the liquid-air surface of the electrolyte. Spectra of optical emissions and scanning electron microscope studies indicate that the plasmoids glow because of a combination of chemiluminescence, atomic and molecular excitation, and possible incandescence from small particulates.

Stephan, Karl D.; Dumas, Shelby; Komala-Noor, Laurence; McMinn, Jonathan



Physiologic versatility and growth flexibility as the main characteristics of a novel thermoacidophilic Acidianus strain isolated from Copahue geothermal area in Argentina.  


A novel thermoacidophilic archaeal strain has been isolated from three geothermal acidic hot springs in Copahue, Argentina. One of the most striking characteristic of ALE1 isolate is its metabolic versatility. It grows on sulphur, tetrathionate, iron (II) and sucrose under aerobic conditions, but it can also develop under anaerobic conditions using iron (III) or sulphur as electron acceptors and sulphur or hydrogen as electron donors autotrophically. A temperature of 75 °C and a pH between 2.5 and 3.0 are strain ALE1 optimal growth conditions, but it is able to oxidise iron (II) even at pH 1.0. Cells are irregular cocci surrounded by a regularly arrayed glycoprotein layer (S-layer). Phylogenetic analysis shows that strain ALE1 belongs to the family Sulfolobaceae in the class Thermoprotei, within the phylum Crenarchaeota. Based on 16S rRNA gene sequence similarity on NCBI database, ALE1 does not have closely related relatives, neither in culture nor uncultured, which is more surprising. Its closest related species are strains of Acidianus hospitalis (91 % of sequence similarity), Acidianus infernus (90 %), Acidianus ambivalens (90 %) and Acidianus manzanensis (90 %). Its DNA base composition of 34.5 % mol C + G is higher than that reported for other Acidianus species. Considering physiological and phylogenetic characteristics of strain ALE1, we considered it to represent a novel species of the genus Acidianus (candidatus "Acidianus copahuensis"). The aim of this study is to physiologically characterise this novel archaea in order to understand its role in iron and sulphur geochemical cycles in the Copahue geothermal area and to evaluate its potential applications in bioleaching and biooxidation. PMID:23052926

Giaveno, M Alejandra; Urbieta, M Sofía; Ulloa, J Ricardo; Toril, Elena González; Donati, Edgardo R



Water uptake characteristics of individual atmospheric particles having coatings  

NASA Astrophysics Data System (ADS)

We used an environmental transmission electron microscope to observe deliquescence and hygroscopic growth of atmospheric particles with hygroscopic coatings over the range 0-100% relative humidity (RH). The particles were collected from polluted and clean environments. Types included a sulfate-coated NaCl/silicate aggregate particle, a sulfate-coated sea-salt particle, and a Mg-rich, chloride-coated sea-salt particle. They all exhibited initial water uptake between 50% and 60% RH, although the first major morphological changes occurred at 70% RH. A deliquescence sphere, adjacent to the core particle, formed between 70% and 76% RH when deliquescence occurred or when the liquid phase was able to break out of the solid exterior coating. The deliquescence sphere grew to engulf the particle with increasing RH. Some particles developed a splatter zone associated with a particle coating. Efflorescence occurred over the range 49-44% RH. Our results indicate that some coated particles undergo a multi-step deliquescence process and that composition of the different phases within the coating affects deliquescence and hygroscopic growth below 76% RH. Above 76% RH, the dominant hygroscopic growth was due to water uptake by NaCl. Efflorescence of these particles also was strongly linked to NaCl, although the presence of other phases inhibited formation of a single NaCl crystal. Our results show that the observed coatings can both enhance particle solubility and lower the effective deliquescence RH of the particle. Thus, these coatings cause important phase and size changes for aerosol particles that could feed back into many other chemical and physical processes that contribute to radiative forcing within the atmosphere.

Semeniuk, Trudi A.; Wise, Matthew E.; Martin, Scot T.; Russell, Lynn M.; Buseck, Peter R.


Hydrogeologic characteristics of four public drinking-water supply springs in northern Arkansas  

USGS Publications Warehouse

In October 2000, a study was undertaken by the U.S. Geological Survey (USGS) in cooperation with the Arkansas Department of Health to determine the hydrogeologic characteristics, including the extent of the recharge areas, for Hughes Spring, Stark Spring, Evening Shade Spring, and Roaring Spring, which are used for public-water supply in northern Arkansas. Information pertaining to each spring can be used to enable development of effective management plans to protect these water resources and public health. An integrated approach to determine the ground-water characteristics and the extent of the local recharge areas of the four springs incorporated tools and methods of hydrology, structural geology, geomorphology, geophysics, and geochemistry. Analyses of discharge, temperature, and water quality were completed to describe ground-water flow characteristics, source-water characteristics, and connectivity of the ground-water system with surface runoff. Water-level contour maps were constructed to determine ground-water flow directions and ground-water tracer tests were conducted to determine the extent of the recharge areas and ground-water flow velocities. Hughes Spring supplies water for the city of Marshall, Arkansas, and the surrounding area. The mean annual discharge for Hughes Spring was 2.9 and 5.2 cubic feet per second for water years 2001 and 2002, respectively. Recharge to the spring occurs mainly from the Boone Formation (Springfield Plateau aquifer). Ground-water tracer tests indicate the recharge area for Hughes Spring generally coincides with the surface drainage area (15.8 square miles) and that Hughes Spring is connected directly to the surface flow in Brush Creek. The geochemistry of Hughes Spring demonstrated variations with flow conditions and the influence of surface-runoff in the recharge area. Calcite saturation indices, total dissolved solids concentrations, and hardness demonstrate noticeable differences with flow conditions reflecting the reduced residence time and interaction of water with the source rock within the ground-water system at higher discharges for Hughes Spring. Concentrations of fecal indicator bacteria also demonstrated a substantial increase during high-flow conditions, suggesting that a non-point source of bacteria possibly from livestock may enter the system. Conversely, nutrient concentrations did not vary with flow and were similar to concentrations reported for undeveloped sites in the Springfield Plateau and Ozark aquifers in northern Arkansas and southern Missouri. Deuterium and oxygen-18 data show that the Hughes Spring discharge is representative of direct precipitation and not influenced by water enriched in oxygen-18 through evaporation. Discharge data show that Hughes Spring is dominated by conduit type ground-water flow, but a considerable component of diffuse flow also exists in the ground-water system. Carbon-13 data indicate a substantial component of the recharge water interacts with the surface material (soil and regolith) in the recharge area before entering the ground-water system for Hughes Spring. Tritium data for Hughes Spring indicate that the discharge water is a mixture of recent recharge and sub-modern water (recharged prior to 1952). Stark Spring supplies water for the city of Cushman, Arkansas, and the surrounding area. 2 Hydrogeologic Characteristics of Four Public Drinking-Water Supply Springs in Northern Arkansas The mean annual discharge for Stark Spring was 0.5 and 1.5 cubic feet per second for water years 2001 and 2002, respectively. The discharge and water-quality data show the ground-water system for Stark Spring is dominated by rapid recharge from surface runoff and mainly consists of a conduit- type flow system with little diffuse-type flow. Analyses of discharge data show that the estimated recharge area (0.79 square mile) is larger than the surface drainage area (0.34 square mile). Ground-water tracer tests and the outcrop of the

Galloway, Joel M.



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.



Climate variability and deep water mass characteristics in the Aegean Sea  

NASA Astrophysics Data System (ADS)

The main objective of this study is to investigate the variability of the thermohaline characteristics of the deep-water masses in the Aegean Sea and the possible impact of the regional atmospheric forcing variability by analyzing the available oceanographic and atmospheric datasets for the period of 1960-2012. During this period the variability of the deep water characteristics of the Aegean sub-basins is found to be very large as well as the diversity of the deep water characteristics among the sub-basins. The Central Aegean seems to play the key role in the Aegean deep water formation processes. Due to its small size, the Aegean Sea surface responds rapidly to the meteorological changes and/or the variability of the lateral fluxes and this variability propagates in the thermohaline characteristics of the deep water masses of the basin through deep water formation processes. There are many episodes characterized by a tight coupling of the atmosphere and the ocean during the examined period, with the Eastern Mediterranean Transient (EMT) being the most prominent case. We suggest that deep water formation is triggered mostly by the combination of preconditioning during early winter and/or previous winters together with the number of subsequent extreme events during present winter and not only by the total amount of the extreme heat loss winter days.

Georgiou, S.; Mantziafou, A.; Sofianos, S.; Gertman, I.; Özsoy, E.; Somot, S.; Vervatis, V.



Polarization characteristics of coastal waters and their impact on in-water visibility  

NASA Astrophysics Data System (ADS)

Polarization characteristics of coastal waters were recently measured during a cruise on the R/V "Connecticut" in the areas of New York Harbor - Sandy Hook, NJ region using a new Stokes vector instrument developed by the Optical Remote Sensing Laboratory at CCNY. The instrument has three hyperspectral Satlantic radiance sensors each with a polarizer positioned in front of it, with polarization axes aligned at 0, 90 and 45°. The measured degrees of polarization (DOPs) and normalized radiances as a function of angle and wavelength match very well with simulated ones obtained with a Monte Carlo radiative transfer code for the atmosphere-ocean system. In order to numerically reproduce the polarized images for underwater horizontal imaging system the measured typical underwater polarized radiance was used to estimate the polarized components of the background veiling light and the blurring effects were modeled by point spread functions obtained from the measured volume scattering functions from this cruise and other typical oceanic environments. It is shown that the visibility can be improved for unpolarized target by placing a polarizer oriented orthogonally to the partially polarized direction of the veiling light before camera. The blurring effects strongly depend on the small angle scattering in the forward directions. For polarized targets the Monte Carlo simulation of slab geometry for polarized pencil light shows that the scattering medium with high g value has a very strong ability to retain the polarization status of the incident light, which can be utilized to improve the image contrasts for targets with very different polarized reflection properties.

Zhou, Jing; Tonizzo, Alberto; Gilerson, Alex; Twardowski, Michael; Gray, Deric; Weidemann, Alan; Arnone, Robert; Gross, Barry; Moshary, Fred; Ahmed, Sam



Insect Physiology Online  

NSDL National Science Digital Library

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



Base water potential of Picea abies as a characteristic of the soil water status  

Microsoft Academic Search

Variation in base water potential (?b, a daily maximum level of plant water potential, which is presumed to correspond to the condition of equilibrium between\\u000a the soil and plant water potentials) was examined in shoots of Norway spruce trees growing in well-drained and waterlogged\\u000a soils. The influence of soil water content, air temperature, and vapour pressure deficit of the atmosphere

Arne Sellin



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


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



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


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



Morphological and physiological responses of Scots pine fine roots to water supply in a dry climatic region in Switzerland.  


In recent decades, Scots pine (Pinus sylvestris L.) forests in inner-Alpine dry valleys of Switzerland have suffered from drought and elevated temperatures, resulting in a higher mortality rate of trees than the mean mortality rate in Switzerland. We investigated the responses of fine roots (standing crop, morphological and physiological features) to water supply in a Scots pine forest in the Rhone valley. Before irrigation started in 2003, low- and high-productivity Scots pine trees were selected based on their crown transparency. The fine root standing crop measured in spring from 2003 to 2005 was unaffected by the irrigation treatment. However, irrigation significantly enhanced the fine root standing crop during the vegetation period when values from spring were compared with values from fall in 2005. Irrigation slightly increased specific root length but decreased root tissue density. Fine root O2-consumption capacity decreased slightly in response to the irrigation treatment. Using ingrowth cores to observe the responses of newly produced fine roots, irrigation had a significantly positive effect on the length of fine roots, but there were no differences between the low- and high-productivity trees. In contrast to the weak response of fine roots to irrigation, the aboveground parts responded positively to irrigation with more dense crowns. The lack of a marked response of the fine root biomass to irrigation in the low- and high-productivity trees suggests that fine roots have a high priority for within-tree carbon allocation. PMID:19203972

Brunner, Ivano; Pannatier, Elisabeth Graf; Frey, Beat; Rigling, Andreas; Landolt, Werner; Zimmermann, Stephan; Dobbertin, Matthias



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.



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


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



Effect of Bedrock infiltration on water balance and rainfall-runoff characteristics in forested headwater catchments  

NASA Astrophysics Data System (ADS)

Water flowing through bedrock plays an important role in stream water runoff generation and the variability in stream water runoff responses in headwater catchments. However, quantification of the contribution of bedrock infiltration to the water balance and runoff generation has been hindered by the difficulty of directly observing bedrock infiltration. To examine the role of bedrock infiltration in the water balance and runoff characteristics in forested headwater catchments, we quantified bedrock infiltration rates using the chloride mass balance method based on rigorous observations of catchment precipitation, discharge, and stream water chemistry in three forested catchments (second- to third-order catchments) underlain by uniform bedrock. We found that bedrock infiltration in forested headwater catchments can be estimated by the chloride mass balance method and that the three catchments differed greatly in terms of bedrock infiltration/recharge and runoff characteristics. In smaller catchments, bedrock recharge/infiltration varied widely, while small bedrock recharge/infiltration was observed in the largest catchment. Although runoff responses differed among the three catchments during base flow, no significant differences were observed in direct runoff ratio and peak flow during large storm events. These results suggest that variability in bedrock infiltration causes spatial variation in water balance and runoff characteristics during low flow, and has a small influence on during high flow in second- to third-order headwater catchments.

Oda, T.; Egusa, T.; Suzuki, M.



Thermal hydraulic characteristics of air–water two-phase flows in helical pipes  

Microsoft Academic Search

Helically coiled heat exchangers, where one of the working fluids is flowing through helical coil, are used in various process industries due to better heat transfer characteristics and the resulting compact layout. Out of these, process requirements make some of the heat exchangers to operate in air–water two-phase region. Even though the characteristics of their operation with single-phase working fluids

J. S. Jayakumar; S. M. Mahajani; J. C. Mandal; Kannan N. Iyer; P. K. Vijayan



ORIGINAL ARTICLE Is fishing selective for physiological and energetic  

E-print Network

ORIGINAL ARTICLE Is fishing selective for physiological and energetic characteristics in migratory, there are no studies that evaluate whether fishing is selective for certain physiological or energetic characteristics physiological or energetic traits. Fish were intercepted during their spawning migrations, implanted

Hinch, Scott G.


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.



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



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.




Technology Transfer Automated Retrieval System (TEKTRAN)

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


Sprectroradiometric characteristics of inland water bodies infestated by Oscillatoria rubescens algae  

NASA Astrophysics Data System (ADS)

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

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



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.



Determination of virtual water content of rice and spatial characteristics analysis in China  

NASA Astrophysics Data System (ADS)

China is a water-stressed country, and agriculture consumes the bulk of its water resources. Assessing the virtual water content (VWC) of crops is one important way to develop efficient water management measures to alleviate water resources conflicts among different sectors. In this research, the VWC of rice, as a major crop in China, was assessed and the spatial characteristics were analyzed. In addition to the calculation of green, blue and grey water - the direct water in VWC - the indirect water use of rice was also calculated, using the Input-Output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water of rice were mainly concentrated in Southeast and Southwest China, while these values were relatively low in Northwest China and Inner Mongolia. The higher direct blue water values were mainly concentrated in the eastern and southern coastal regions and Northwest China, and low values were mainly concentrated in Southwest China. Grey water values were relatively high in Shanxi and Guangxi provinces and low in Northeast and Northwest China. The regions with high values for indirect water were randomly distributed but the regions with low values were mainly concentrated in Northwest and Southwest China. For the regions with relatively high total VWC the high values of blue water made the largest contribution, although for the country as a whole the direct green water is the most important contributor.

Zhang, L. J.; Yin, X. A.; Zhi, Y.; Yang, Z. F.



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


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



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.



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



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


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



Use of an automated chromium reduction system for hydrogen isotope ratio analysis of physiological fluids applied to doubly labeled water analysis.  


The doubly labeled water method is commonly used to measure total energy expenditure in free-living subjects. The method, however, requires accurate and precise deuterium abundance determinations, which can be laborious. The aim of this study was to evaluate a fully automated, high-throughput, chromium reduction technique for the measurement of deuterium abundances in physiological fluids. The chromium technique was compared with an off-line zinc bomb reduction technique and also subjected to test-retest analysis. Analysis of international water standards demonstrated that the chromium technique was accurate and had a within-day precision of <1 per thousand. Addition of organic matter to water samples demonstrated that the technique was sensitive to interference at levels between 2 and 5 g l(-1). Physiological samples could be analyzed without this interference, plasma by 10000 Da exclusion filtration, saliva by sedimentation and urine by decolorizing with carbon black. Chromium reduction of urine specimens from doubly labeled water studies indicated no bias relative to zinc reduction with a mean difference in calculated energy expenditure of -0.2 +/- 3.9%. Blinded reanalysis of urine specimens from a second doubly labeled water study demonstrated a test-retest coefficient of variation of 4%. The chromium reduction method was found to be a rapid, accurate and precise method for the analysis of urine specimens from doubly labeled water. PMID:11006607

Schoeller, D A; Colligan, A S; Shriver, T; Avak, H; Bartok-Olson, C



Pervaporative dehydration characteristics of an ethanol/water azeotrope through various chitosan membranes.  


The permeation and separation characteristics of an ethanol/water azeotrope through chitosan membranes of different molecular weights and degrees of deacetylation during pervaporation were investigated. The normalized permeation rate decreased with increasing molecular weight up to 90kDa, but at over 90kDa, the rate increased. On the other hand, the water/ethanol selectivity increased with increasing molecular weight up to 90kDa but decreased at over 90kDa. With increasing degree of deacetylation, the water/ethanol permselectivity increased significantly, but the normalized permeation rate decreased. The characteristics of chitosan membranes are discussed based on their chemical and physical structures such as the contact angle, density, degree of swelling, and glass transition temperature. PMID:25662680

Uragami, Tadashi; Saito, Tomoyuki; Miyata, Takashi



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

NASA Astrophysics Data System (ADS)

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

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



Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices  

NASA Astrophysics Data System (ADS)

This paper deals with the monitoring of water status and the assessment of the effect of stress on citrus fruit quality using structural and physiological remote sensing indices. Four flights were conducted over a citrus orchard in 2009 using an unmanned aerial vehicle (UAV) carrying a multispectral camera with six narrow spectral bands in the visible and near infrared. Physiological indices such as the Photochemical Reflectance Index (PRI570), a new structurally robust PRI formulation that uses the 515 nm as the reference band (PRI515), and a chlorophyll ratio (R700/R670) were compared against the Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI) and Modified Triangular Vegetation Index (MTVI) canopy structural indices for their performance in tracking water status and the effects of sustained water stress on fruit quality at harvest. The irrigation setup in the commercial orchard was compared against a treatment scheduled to satisfy full requirements (based on estimated crop evapotranspiration) using two regulated deficit irrigation (RDI) strategies. The water status of the trees throughout the experiment was monitored with frequent field measurements of stem water potential (?x), while titratable acidity (TA) and total soluble solids (TSS) were measured at harvest on selected trees from each irrigation treatment. The high spatial resolution of the multispectral imagery (30 cm pixel size) enabled identification of pure tree crown components, extracting the tree reflectance from shaded, sunlit and aggregated pixels. The physiological and structural indices were then calculated from each tree at the following levels: (i) pure sunlit tree crown, (ii) entire crown, aggregating the within-crown shadows, and (iii) simulating a lower resolution pixel, including tree crown, sunlit and shaded soil pixels. The resulting analysis demonstrated that both PRI formulations were able to track water status, except when water stress altered canopy structure. In such cases, PRI570 was more affected than PRI515 by the structural changes caused by sustained water stress throughout the season. Both PRI formulations were proven to serve as pre-visual water stress indicators linked to fruit quality TSS and TA parameters (r2 = 0.69 for PRI515 vs TSS; r2 = 0.58 vs TA). In contrast, the chlorophyll (R700/R670) and structural indices (NDVI, RDVI, MTVI) showed poor relationships with fruit quality and water status levels (r2 = 0.04 for NDVI vs TSS; r2 = 0.19 vs TA). The two PRI formulations showed strong relationships with the field-measured fruit quality parameters in September, the beginning of stage III, which appeared to be the period most sensitive to water stress and the most critical for assessing fruit quality in citrus. Both PRI515 and PRI570 showed similar performance for the two scales assessed (sunlit crown and entire crown), demonstrating that within-crown component separation is not needed in citrus tree crowns where the shaded vegetation component is small. However, the simulation conducted through spatial resampling on tree + soil aggregated pixels revealed that the physiological indices were highly affected by soil reflectance and between-tree shadows, showing that for TSS vs PRI515 the relationship dropped from r2 = 0.69 to r2 = 0.38 when aggregating soil + crown components. This work confirms a previous study that demonstrated the link between PRI570, water stress, and fruit quality, while also making progress in assessing the new PRI formulation (PRI515), the within-crown shadow effects on the physiological indices, and the need for high resolution imagery to target individual tree crowns for the purpose of evaluating the effects of water stress on fruit quality in citrus.

Stagakis, S.; González-Dugo, V.; Cid, P.; Guillén-Climent, M. L.; Zarco-Tejada, P. J.



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

NASA Astrophysics Data System (ADS)

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

Zhou, M.; Zheng, Y.



The Relationship between Phytoplankton Distribution and Water Column Characteristics in North West European Shelf Sea Waters  

PubMed Central

Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the “Ellett Line” cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA), of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations) clearly discriminated between shelf and oceanic stations on the basis of DIN?DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS) demonstrating spatial variability in its composition. Redundancy analysis (RDA) was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community), and both salinity and DIN?DSi (diatoms alone). Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi limitation of growth at most stations and depths. PMID:22479533

Davidson, Keith; Bolch, Christopher J. S.; Brand, Tim D.; Narayanaswamy, Bhavani E.



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


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



Environmental characteristics and water quality of hydrologic benchmark network stations in the western United States, 1963-95  

USGS Publications Warehouse

This report describes the environmental characteristics and water-quality characteristics of 12 hydrologic benchmark network streams in the Western United States. This information was compiled to aide in the interpretation and application of water-quality data collected as part of the Hydrologic Benchmark Network Program.

Mast, M. Alisa; Clow, David W.



Environmental characteristics and water quality of hydrologic benchmark network stations in the west-central United States, 1963-95  

USGS Publications Warehouse

This report describes the environmental characteristics and water-quality characteristics of 14 benchmark basins in the west-central United States. The information was compiled to aide in the interpretation and application of historical water-quality data collected through the Hydrologic Benchmark Network Program.

Clark, Melanie L.; Eddy-Miller, C. A.; Mast, M. Alisa



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

NASA Astrophysics Data System (ADS)

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

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



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



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

USGS Publications Warehouse

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

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



Determination of water flushing characteristics and their influencing factors on the Dahuofang Reservoir in China using an improved ECOMSED model  

NASA Astrophysics Data System (ADS)

A three-dimensional hydrodynamic model with the capability to deal with changing land water boundaries was developed based on ECOMSED in this study. The model was configured to numerically study the water flushing characteristics of Dahuofang Reservoir in China through the determination of spatially distributed residence times. The model successfully reproduced the intra-annual water level variations, as well as the temporal evolution and spatial distribution of water temperature. Through a series of numerical experiments, it can be concluded that (1) the water flushing of the reservoir is both temporally and spatially variable; and (2) inflows and withdrawals are the decisive factors influencing the water flushing characteristics. Heat fluxes are the controlling factors of the water flushing of a strong stratified reservoir. Wind has the weakest effect, but it still should be considered in determination of reservoir water flushing characteristics.

Zhang, Ming; Shen, Yongming



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

NASA Astrophysics Data System (ADS)

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

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



A characteristic function to estimate the longitudinal dispersion coefficient in surface water flows over porous media  

NASA Astrophysics Data System (ADS)

One-dimensional modelling of solute transport in shallow water flows relies on an accurate approximation of the longitudinal dispersion coefficient, E, especially under transient conditions of the water flow during the solute residence time. Previous approaches have used expressions (e.g., the Rutherford equation) that allow the inclusion of spatiotemporal variability of E during the transport process, but their accuracy is reduced in marked transient regimes since the data were obtained from experimental work in rivers. This work proposes a different approach from experimental work with slow, shallow flows over porous media in fertigation essays, and provides us with a simple, parametric sigmoid function to estimate a priori effective values of E from simple measurements of flow characteristics and variables. The results have been successfully validated and compared to the Rutherford equation approach. Furthermore, the methodology to develop this characteristic function can be easily adapted for application in other practical cases.

Nofuentes, M.; Polo, M. J.



Effects of diesel engine speed and water content on emission characteristics of three-phase emulsions.  


The effects of water content of three-phase emulsions and engine speed on the combustion and emission characteristics of diesel engines were investigated in this study. The results show that a larger water content of water-in oil (W/O) and oil-in-water-in-oil (O/W/O) emulsion caused a higher brake specific fuel consumption (bsfc) value and a lower O2, as well as a lower NOx emission, but a larger CO emission. The increase in engine speed resulted in an increase of bsfc, exhaust gas temperature, fuel-to-air ratio, CO2 emission and a decrease of NOx, CO emission, and smoke opacity. Because of the physical structural differences, the three-phase O/W/O emulsions were observed to produce a higher exhaust gas temperature, a higher emulsion viscosity and a lower CO emission, in comparison with that of the two-phase W/O emulsion. In addition, the use of W/O emulsions with water content larger than 20% may cause diesel engines to shut down earlier than those running on O/W/O emulsions with the same water content. Hence, it is suggested that the emulsions with water content larger than 20% are not suitable for use as alternative fuel for diesel engines. PMID:15137702

Lin, Cherng-Yuan; Wang, Kuo-Hua



The water withdraws and spectral characteristic analysis of back groundsurface features in Zengcheng City  

NASA Astrophysics Data System (ADS)

Many achievements in studies of extracting water have been made in the past ten years.According to the foundation of remote sensing and spectrum theory, the general extracting principal of remote sensing information is introduced. Zengcheng was rich in water resources, and it is an idel back garden of Guangzhou city. Therefore, it is important to use the water resources rationally in Zengcheng.TM image dated 10 November 2006 was elected in this paper.Both interpreted maps were analyzed and managed by ENVI and ArcGIS software. Single-band threshold method, the relationship between spectrum, vegetation index and water index method were used in this paper. At last, Water index method was considered to be the most suitable one after a comparative analysis.In this paper landscape types within the study area were classified into (1) farmland, (2)forest land, (3)urban Inhabitant land and other land,(4)orchard land, (5)unused land, (6)water, with the help of Land cover map 2006 of Zengcheng. A reconnaissance survey of the study area was made to correlate the image characteristics and ground features by the standard technique of human-computer 'dialogue' interpretation.According to the foundation of remote sensing and spectrum theory, a model of water body extraction is set up in this paper.

Gao, Ai; Xia, Lihua



Physiological Waterfalls  

ERIC Educational Resources Information Center

Provides background information, defining areas within organ systems where physiological waterfalls exist. Describes pressure-flow relationships of elastic tubes (blood vessels, airways, renal tubules, various ducts). (CS)

Leith, David E.



Effect of structural heterogeneity water-coal fuel conditions and characteristics of ignition  

NASA Astrophysics Data System (ADS)

The problem of the particle ignition of coal-water fuel (CWF) with a joint course of the main processes of a thermal (thermal conductivity, evaporation, filtration heat and mass transfer, thermal decomposition of the organic part) has been solved. According to the results of numerical simulation ways of describing the extent of the influence of the thermophysical properties on the characteristics and conditions of ignition WCF have been set.

Syrodoy, S. V.; Salomatov, V. V.; Gutareva, N. Y.



Flow characteristics of water in straight and serpentine micro-channels with miter bends  

Microsoft Academic Search

Flow characteristics of pressure-driven de-ionized water were investigated experimentally in straight and serpentine micro-channels with miter bends. The micro-channels had rectangular cross-sections with hydraulic diameters of 0.209mm, 0.395mm and 0.549mm. To evaluate bend loss coefficient in the serpentine micro-channel and micro-scale size effect on it, the additional pressure drop due to the miter bend must be obtained. This additional pressure

Renqiang Xiong; Jacob N. Chung



Performance and heat transfer characteristics of HFC134a and CFC12 in a water chiller  

Microsoft Academic Search

A water chiller with an open reciprocating compressor has been used to comparatively assess the performance of HFC-134a with reference to CFC-12 under as close to identical conditions as possible. Performance characteristics of the chiller under retrofit conditions show that HFC-134a offers better cooling load and coefficients of performance vis-a-vis CFC-12 for identical operating conditions. Further heat transfer analysis of

S. Devotta; M. G. Parande; V. R. Patwardhan



Application of the characteristic CIP method to a shallow water model on the sphere  

Microsoft Academic Search

Semi-implicit algorithms are popularly used to deal with the gravitational term in numerical models. In this paper, we adopt\\u000a the method of characteristics to compute the solutions for gravity waves on a sphere directly using a semi-Lagrangian advection\\u000a scheme instead of the semi-implicit method in a shallow water model, to avoid expensive matrix inversions. Adoption of the\\u000a semi-Lagrangian scheme renders

Xindong Peng; Yan Chang; Xingliang Li; Feng Xiao



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.



Physiological performance of an Alaskan shrub (Alnus fruticosa) in response to disease (Valsa melanodiscus) and water stress  

Technology Transfer Automated Retrieval System (TEKTRAN)

At northern latitudes, plants are being exposed to multiple climate-related stresses as warming temperatures push plants beyond the physiological limits of their current range. Our study focused on two stresses related to the warming and drying of the Alaskan boreal forest: drought and disease. We e...


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



Conservation physiology  

Microsoft Academic Search

Conservation biologists increasingly face the need to provide legislators, courts and conservation managers with data on causal mechanisms underlying conservation problems such as species decline. To develop and monitor solutions, conservation biologists are progressively using more techniques that are physiological. Here, we review the emerging discipline of conservation physiology and suggest that, for conservation strategies to be successful, it is

Martin Wikelski; Steven J. Cooke



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.



Characteristic of Local Boiling Heat Transfer of Ammonia / Water Binary Mixture on the Plate Type Evaporator  

NASA Astrophysics Data System (ADS)

Ocean thermal energy conversion (OTEC) and discharged thermal energy conversion (DTEC) are expected to be the next generation energy production systems. Both systems use a plate type evaporator, and ammonia or ammonia/water mixture as a working fluid. It is important to clarify heat transfer characteristic for designing efficient power generation systems. Measurements of local boiling heat transfer coefficients and visualization were performed for ammonia /water mixture (z = 0.9) on a vertical flat plate heat exchanger in a range of mass flux (7.5 - 15 kg/m2s), heat flux (15 - 23 kW/m2), and pressure (0.7 - 0.9 MPa). The result shows that in the case of ammonia /water mixture, the local heat transfer coefficients increase with an increase of vapor quality and mass flux, and decrease with an increase of heat flux, and the influence of the flow pattern on the local heat transfer coefficient is observed.

Okamoto, Akio; Arima, Hirofumi; Kim, Jeong-Hun; Akiyama, Hirokuni; Ikegami, Yasuyuki; Monde, Masanori


Characteristics of impact-driven high-speed liquid jets in water  

NASA Astrophysics Data System (ADS)

This paper describes a preliminary investigation of the characteristics of high-speed water jets injected into water from an orifice. The high-speed jets were generated by the impact of a projectile launched by a horizontal single-stage powder gun and submerged in a water test chamber. The ensuing impact-driven high-speed water jets in the water were visualized by the shadowgraph technique, and the images were recorded by a high-speed digital video camera. The processes following such jet injection into water, the jet-induced shock waves, shock wave propagation, the bubble behavior, bubble collapse-induced rebound shock waves and bubble cloud re-generation were observed. Peak over-pressures of about 24 and 35 GPa measured by a Polyvinylidence difluoride (PVDF) piezoelectric film pressure sensor were generated by the jet impingement and the bubble impingement, respectively. The peak over-pressure was found to decrease exponentially as the stand-off distance between the PVDF pressure sensor and the nozzle exit increases.

Matthujak, A.; Kasamnimitporn, C.; Sittiwong, W.; Pianthong, K.; Takayama, K.; Milton, B. E.





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

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



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

USGS Publications Warehouse

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

Bradfield, A.D.



Acoustical characteristics of water sounds for soundscape enhancement in urban open spaces.  


The goal of the present study is to characterize water sounds that can be used in urban open spaces to mask road traffic noise. Sounds and visual images of a number of water features located in urban open places were obtained and subsequently analyzed in terms of psychoacoustical metrics and acoustical measures. Laboratory experiments were then conducted to investigate which water sound is appropriate for masking urban noise. The experiments consisted of two sessions: (1) Audio-only condition and (2) combined audio-visual condition. Subjective responses to stimuli were rated through the use of preference scores and 15 adjectives. The results of the experiments revealed that preference scores for the urban soundscape were affected by the acoustical characteristics of water sounds and visual images of water features; Sharpness that was used to explain the spectral envelopes of water sounds was proved to be a dominant factor for urban soundscape perception; and preferences regarding the urban soundscape were significantly related to adjectives describing "freshness" and "calmness." PMID:22423706

Jeon, Jin Yong; Lee, Pyoung Jik; You, Jin; Kang, Jian



Can we measure the aerosol and cloud liquid characteristics by using Mie and liquid-water Raman lidar?  

Microsoft Academic Search

Liquid water Raman signal was measured and normalized by Mie and water vapor Raman signals. In simple theoretical point of view, these normalized cloud liquid water lidar signals have information about the aerosol hydroscopic characteristics and cloud size information. We obtained the qualitative information for these parameters at the cloud and normal atmospheric aerosol. Here we have discussed the possibility

Dukhyeon Kim; Sunho Park; Hai-Du Cheong; Wonseok Choi; Yong-Gi Kim; Moonsang Yun; Imkang Song



Microstructure and shear fracture characteristics of porous anodic TiO 2 layer before and after hot water treatment  

Microsoft Academic Search

Porous TiO2 layer was fabricated on the surface of commercially pure titanium using an anodic spark oxidation technique for biomedical application, and subsequent hot water treatment was performed to modify the resultant oxide layer. The microstructure features and shear fracture characteristics of anodic oxide layer before and after water treatment were investigated. Results show that before water treatment, the oxide

Z. X. Chen; W. X. Wang; Y. Takao; T. Matsubara; L. M. Ren



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


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

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



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


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



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

USGS Publications Warehouse

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

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



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


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



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



Study of Cold Heat Energy Release Characteristics of Flowing Ice Water Slurry in a Pipe  

NASA Astrophysics Data System (ADS)

This paper has dealt with melting heat transfer characteristics of ice water slurry in an inside tube of horizontal double tube heat exchanger in which a hot water circulated in an annular gap between the inside and outside tubes. Two kinds of heat exchangers were used; one is made of acrylic resin tube for flow visualization and the other is made of stainless steel tube for melting heat transfer measurement. The result of flow visualization revealed that ice particles flowed along the top of inside tube in the ranges of small ice packing factor and low ice water slurry velocity, while ice particles diffused into the whole of tube and flowed like a plug built up by ice particles for large ice packing factor and high velocity. Moreover, it was found that the flowing ice plug was separated into numbers of small ice clusters by melting phenomenon. Experiments of melting heat transfer were carried out under some parameters of ice packing factor, ice water slurry flow rate and hot water temperature. Consequently, the correlation equation of melting heat transfer was derived as a function of those experimental parameters.

Inaba, Hideo; Horibe, Akihiko; Ozaki, Koichi; Yokota, Maki


Water landing characteristics of a model of a winged reentry vehicle  

NASA Technical Reports Server (NTRS)

Proposed manned space shuttle vehicles are expected to land on airport runways. In an emergency situation, however, the vehicle may be required to land on water. A 1/10-scale dynamic model of a winged reentry vehicle was investigated to determine the water landing characteristics. Two configurations of the proposed vehicle were studied. Configuration 1 had a 30 deg negative dihedral of the stabilizer-elevon surface whereas configuration 2 had a 30 deg positive dihedral. Results indicate that the maximum normal accelerations for configurations 1 and 2 when landing in calm water were approximately 8g and 6g, respectively, and the maximum longitudinal accelerations were approximately 5g and 3g, respectively. A small hydroflap was needed to obtain satisfactory calm-water landings with configuration 2, whereas configuration 1 gave good landings without a hydroflap. All landings made in rough water resulted in unsatisfactory motions. For landings made in three different wave sizes, both configurations dived. The maximum normal accelerations for configurations 1 and 2 when landing in waves were -10.1g and -18.7g, respectively, and the maximum longitudinal accelerations for both configurations were approximately 13g.

Stubbs, S. M.



Experimental determination of water droplet "strain cycles" characteristic in the gas area  

NASA Astrophysics Data System (ADS)

Experimental investigation of deformation regularities of widely used in industry liquid (water, kerosene, ethanol) droplets during the motion through the gas area under the action of gravitational forces has been conducted. Droplet characteristic sizes were varied in the range from 3 mm to 6 mm. Droplet motion velocities were come up to 5 m/s. Cross-correlation video recording system with optical methods of droplet size and velocity measurement was used. More than 10 characteristic droplets "strain cycles" have been established during they pass the distances up to 1 m through the gas area. The characteristic droplet forms, times, extents and amplitudes have been determined for each "strain cycle". The expression has been formulated which describes the characteristic "strain cycles" time dependencies on droplet velocities and sizes, also on the fundamental properties (viscosity, density, surface tension) of liquid and gas area in a first approximation. The conditions of droplet deformation intensification and this process in industry gas-vapor-droplet setups stabilization have been determined.

Kuznetsov, Genii V.; Strizhak, Pavel A.; Volkov, Roman S.; Zabelin, Maxim V.



[Effects of irrigation amount on morphological characteristics and water use of Jatropha curcas].  


Jatropha curcas is the most promising energy tree, and soil moisture is the key factor which affects the seedling quality and water use efficiency of J. curcas. With aims to evaluate the effect of different irrigation amount on growth, morphological characteristics and water use of J. curcas, a pot experiment was conducted with four irrigation amounts, i. e., W1:472.49 mm, W2: 228.79 mm, W3:154.18 mm and W4:106.93 mm, respectively. Compared with W1 treatment, the leaf area and stem cross-section area of base significantly decreased in W2, W3 and W4 treatments, but Huber value significantly increased, which could improve the efficiency of water transfer from root to shoot, thus enhance the capability of resistance to drought stress. Compared with W, treatment, the healthy index of J. curcas seedlings decreased slightly in W2 treatment but significantly decreased in W3 and W4 treatments. Hence, the irrigation amount from 228.79 to 472.49 mm was beneficial to increase the healthy index of J. curcas seedlings. Compared with W1 treatment, irrigation water was saved by 67.4% in W3 treatment, and the total dry mass and evapotranspiration significantly decreased by 17.4% and 68.6%, and the irrigation water use efficiency and total water use efficiency increased by 153.2% and 163.2%, respectively. In the condition of this study, the irrigation amount of 154.18 mm was beneficial to increase water use efficiency. PMID:25129933

Yang, Qi-Liang; Zhang, Jing; Liu, Xiao-Gang; Liu, Yan-Wei; Yang, Ju-Rui



A Study of the Flow Characteristics in Air-Water Two-Phase Flow under Microgravity  

NASA Astrophysics Data System (ADS)

Reliable design of space thermal management systems requires a through understanding of the hydrodynamic characteristics of two-phase flow influenced by the change in gravity. The data of flow patterns, void fraction, frictional pressure drop associated with its characteristics were obtained at normal gravity and in microgravity and hyper-gravity (2g) conditions aboard MU-300 aircraft capable of parabolic trajectory flying. Some experiments were performed for an air-water two-phase flow through 10mm diameter adiabatic test section with 600mm length of transparent acrylic resin horizontal tube. The results obtained at three gravity levels (µg, 1g and 2g) are compared with some of the existing flow pattern transition, void fraction and frictional pressure drop models and correlations. The gravity dependency of flow patterns was more clearly appeared with the decrease in gas and liquid flow rates. The effect of gravity on two-phase flow was insignificant for the turbulent flow regions.

Choi, Buhong; Fujii, Terushige; Asano, Hitoshi; Sugimoto, Katsumi


Synthetic Physiology  

E-print Network

Optogenetic tools are DNA-encoded molecules that, when genetically targeted to cells, enable the control of specific physiological processes within those cells through exposure to light. These tools can pinpoint how these ...

Boyden, Edward Stuart


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.



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




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

NASA Astrophysics Data System (ADS)

To meet the needs of those exploiting deepwater resources, TLP and SPAR platforms are used in some areas and are considered excellent platforms in deep water. However, many problems remain to be resolved. The design of mooring systems is a key issue for deep water platforms. Environmental loads in deep water effect the physical characteristics of mooring line materials. The configuration and analysis of mooring systems involve nonlinearity due to this fluid-solid coupling, nonlinear hydrodynamic forces, and their effects on stability of motion. In this paper, some pivotal theories and technical questions are presented, including modeling of mooring lines, the theory and method of coupled dynamics analysis on the mooring system, and the development of methodologies for the study of nonlinear dynamics of mooring systems. Further study on mooring systems in deep water are recommended based on current knowledge, particularly dynamic parameters of different materials and cable configuration, interactions between seabed and cable, mechanisms of mooring system response induced by taut/slack mooring cables, discontinuous stiffness due to system materials, mooring construction, and motion instability, etc.

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



[Change characteristics of climate and water resources in west Liaohe River Plain].  


Based on the 1951-2007 observation data of precipitation and temperature from Tongliao, Kailu, and Zhalute meteorological stations as well as the related hydrologic data from Tongliao hydrological survey bureau and water affairs bureau, the change characteristics of the climate and water resources in west Liaohe River Plain were studied. The results showed that in 1951-2007, the precipitation in its periodical changes in study area had a decreasing trend. The tendency rate of precipitation was -13.2 mm x (10 a)(-1), and the instability of precipitation was increased. The runoff of four inbound rivers including Xilamulun all decreased, with the mean annual runoff in 2001-2007 being only 22.8% of that in 1990-1994. From 1951 to 2007, the runoff of west Liaohe River decreased, and the days of its zero flow increased. Since 2001, the River had been zero flow. The groundwater overdraft area and the funnel area in Keerqin Region in 2006 increased by 8.5 times and 15.5 times, respectively, compared with those in 1978; and the average groundwater level in Keerqin Region, Kailu County, and Naiman Banner in 2006 increased by 3.76 m, 2.77 m, and 1.93 m, respectively, compared with that in 1980. Since the 1970s, the number of electromechanical well in study area was increasing, irrigation amount had a fluctuated rise, and the proportion of agricultural water consumption had different extent decrease. Therefore, to exploit and use the water resources in atmosphere, to popularize water-saving irrigation technologies, and to make a reasonable arrangement of industrial structure were the effective measures in realizing the sustainable utilization of water resources in west Liaohe River Plain. PMID:19449570

Yang, Heng-shan; Liu, Jiang; Liang, Huai-yu



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



Have we been ignoring physiological plasticity and genetic variation in stomatal function as a significant source of error in models of water and carbon fluxes?  

NASA Astrophysics Data System (ADS)

Accurately predicting plant and ecosystem function across climatic and ecological gradients requires properly parameterized models of both net photosynthetic assimilation of CO2 and stomatal conductance. Photosynthesis models have been parameterized to account for physiological plasticity and genetic variation for decades. However, models describing physiological plasticity or genetic variation in the sensitivity of stomatal conductance to net photosynthetic CO2 assimilation (A), relative humidity (RH), and atmospheric [CO2] have rarely, if ever, been applied. There is no mechanistic basis for the prevailing assumption that models of stomatal conductance can share a universal parameterization for all C3 species. Twelve species of temperate trees were grown in a common garden to test species-specific sensitivity of stomatal conductance to A, RH and [CO2]. Additionally, a Salix and a Populus genotype, grown at three locations throughout the Eastern US in biofuels trails, were measured at three times during the growing season to test for temporal and spatial effects. Soybean was also grown at eight ozone concentrations to test for physiological plasticity in stomatal function. Laboratory-based gas exchange measurements were used to parameterize the widely used Ball et al. (1987) model of stomatal conductance and the Farquhar et al. (1980) model of photosynthesis. These models were coupled to each other and a leaf energy balance model in order to predict in situ leaf CO2 and water fluxes which were compared against field measurements. There was significant physiological plasticity and genetic variation in the sensitivity of stomatal conductance to A, RH and [CO2]. This was reflected in significant variation in parameters of the Ball et al. (1987) model, with the key slope parameter (m) ranging from more than 4-fold. Context-specific parameterization of this widely used stomatal conductance model reduced error in predictions of in situ leaf A and gs by up to 59%, compared to the commonly used generic parameterization (m = 10, g0 = 0). This suggests that parameterization of stomatal conductance models to reflect physiological plasticity and genetic variation in function would be an effective method to improve the accuracy of plant and ecosystem models that are key tools in the study of global environmental change and sustainable agriculture.

Wertin, T. M.; Wolz, K.; Richter, K.; Adorbo, M.; Betzelberger, A. M.; Leakey, A.



Physiological traits of Penicillium glabrum strain LCP 08.5568, a filamentous fungus isolated from bottled aromatised mineral water  

Microsoft Academic Search

Penicillium glabrum is a ubiquitous fungus distributed world wide. This fungus is a frequent contaminant in the food manufacturing industry. Environmental factors such as temperature, water activity and pH have a great influence on fungal development. In this study, a strain of P. glabrum referenced to as LCP 08.5568, has been isolated from a bottle of aromatised mineral water. The

L. Nevarez; V. Vasseur; A. Le Madec; M. A. Le Bras; L. Coroller; I. Leguérinel; G. Barbier



Red spruce physiology and growth in response to elevated CO[sub 2], water stress and nutrient limitations  

SciTech Connect

Spruce-fir ecosystems of the eastern United States interest scientists because of reported changes in population growth. This research examined the growth and physical responses of red spruce seedlings (Picea rubens Sarg.) to change in atmospheric CO[sub 2], water and nutrient availability to determine the response of this species to potential climatic changes. Red spruce seedlings were grown from seed for 1 year in ambient (374 ppm) or elevated (713 ppm) CO[sub 2] in combination with low or high soil fertility treatment, and well-watered or water-stressed conditions. Red spruce seedlings grown with limited nutrient and water availability increased growth in elevated CO[sub 2] as did seedlings grown with high soil fertility treatment and ample water. At 12 months of age, elevated CO[sub 2]-grown seedlings had greater dry weight, height, diameter and specific leaf weight than ambient CO[sub 2[minus

Samuelson, L.J.



Hydraulic characteristics of, and ground-water flow in, coal-bearing rocks of southwestern Virginia  

USGS Publications Warehouse

This report presents the results of a study by the U.S Geological Survey, in cooperation with the Virginia Department of Mines, Minerals, and Energy, Division of Mined Land Reclamation, and the Powell River Project, to describe the hydraulic characteristics of major water-bearing zones in the coal-bearing rocks of southwestern Virginia and to develop a conceptual model of the ground-water-flow system. Aquifer testing in1987 and 1988 of 9-ft intervals in coal-exploration coreholes indicates that transmissivity decreases with increasing depth. Most rock types are permeable to a depth of approximately 100 ft; however, only coal seams are consistently permeable (transmissivity greater than 0.001 ft/d) at depths greater than 200 ft . Constant-head injection testing of rock intervals adjacent to coal seams usually indicated lower values of transmissivity than those values obtained when coal seams were isolated within the test interval; thus, large values of horizontal hydraulic conductivity at depth are associated with coal seams. Potentiometric-head measurements indicate that high topographic areas (ridges) function as recharge areas; water infiltrates through the surface, percolates into regolith, and flows downward and laterally through fractures in the shallow bedrock. Hydraulic conductivity decreases with increasing depth, and ground water flows primarily in the lateral direction along fractures or bedding planes or through coal seams. If vertical hydraulic conductivity is negligible, ground water continues to flow laterally, discharging as springs or seeps on hill slopes. Where vertical hydraulic conductivity is appreciable, groundwater follows a stair step path through the regolith, fractures, bedding planes, and coal seams, discharging to streams and (or) recharging coal seams at depth. Permeable coal seams probably underlie valleys in the region; however, aquifer-test data indicate that the horizontal hydraulic conductivity of coal is a function of depth and probably decreases under ridges because of increased overburden pressures. Ground water beneath valleys that does not discharge to streams probably flows down gradient as underflow beneath the streams. Topographic relief in the area provides large hydraulic-head differences (greater than 300 ft in some instances) for the ground-water-flow system. Transmissivity data from the range of depths tested during this study indicate that most ground-water flow takes place at moderate depths (less than 300 ft) and that little deep regional ground-water flow occurs.

Harlow, George E.; LeCain, Gary D.



Integrated transcriptomic and proteomic analysis of the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions of cold and water activity stress.  


An integrated transcriptomic and proteomic analysis was undertaken to determine the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air. The response of E. coli during exponential growth at 25 °C a(w) 0.985, 14 °C a(w) 0.985, 25 °C a(w) 0.967, and 14 °C a(w) 0.967 was compared with that of a reference culture (35 °C a(w) 0.993). Gene and protein expression profiles of E. coli were more strongly affected by low water activity (a(w) 0.967) than by low temperature (14 °C). Predefined group enrichment analysis revealed that a universal response of E. coli to all test conditions included activation of the master stress response regulator RpoS and the Rcs phosphorelay system involved in the biosynthesis of the exopolysaccharide colanic acid, as well as down-regulation of elements involved in chemotaxis and motility. However, colanic acid-deficient mutants were shown to achieve comparable growth rates to their wild-type parents under all conditions, indicating that colanic acid is not required for growth. In contrast to the transcriptomic data, the proteomic data revealed that several processes involved in protein synthesis were down-regulated in overall expression at 14 °C a(w) 0.985, 25 °C a(w) 0.967, and 14 °C a(w) 0.967. This result suggests that during growth under these conditions, E. coli, although able to transcribe the required mRNA, may lack the cellular resources required for translation. Elucidating the global adaptive response of E. coli O157:H7 during exposure to chilling and water activity stress has provided a baseline of knowledge of the physiology of this pathogen. PMID:22008207

Kocharunchitt, Chawalit; King, Thea; Gobius, Kari; Bowman, John P; Ross, Tom



Integrated Transcriptomic and Proteomic Analysis of the Physiological Response of Escherichia coli O157:H7 Sakai to Steady-state Conditions of Cold and Water Activity Stress*  

PubMed Central

An integrated transcriptomic and proteomic analysis was undertaken to determine the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air. The response of E. coli during exponential growth at 25 °C aw 0.985, 14 °C aw 0.985, 25 °C aw 0.967, and 14 °C aw 0.967 was compared with that of a reference culture (35 °C aw 0.993). Gene and protein expression profiles of E. coli were more strongly affected by low water activity (aw 0.967) than by low temperature (14 °C). Predefined group enrichment analysis revealed that a universal response of E. coli to all test conditions included activation of the master stress response regulator RpoS and the Rcs phosphorelay system involved in the biosynthesis of the exopolysaccharide colanic acid, as well as down-regulation of elements involved in chemotaxis and motility. However, colanic acid-deficient mutants were shown to achieve comparable growth rates to their wild-type parents under all conditions, indicating that colanic acid is not required for growth. In contrast to the transcriptomic data, the proteomic data revealed that several processes involved in protein synthesis were down-regulated in overall expression at 14 °C aw 0.985, 25 °C aw 0.967, and 14 °C aw 0.967. This result suggests that during growth under these conditions, E. coli, although able to transcribe the required mRNA, may lack the cellular resources required for translation. Elucidating the global adaptive response of E. coli O157:H7 during exposure to chilling and water activity stress has provided a baseline of knowledge of the physiology of this pathogen. PMID:22008207

Kocharunchitt, Chawalit; King, Thea; Gobius, Kari; Bowman, John P.; Ross, Tom



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



Differential growth, physiological and biochemical responses of niger ( Guizotia abyssinica Cass.) cultivars to water-deficit (drought) stress  

Microsoft Academic Search

The present study demonstrates the effect of polyethylene glycol-8000 (PEG) and percent field capacity (FC%)-induced water-deficit\\u000a stress on growth, water status, productivity and various biochemical parameters in Guizotia abyssinica Cass. cultivars (IGP 76, GA 10, No. 71 and IGPN 2004) at seedling and maturity stages of the plant. Cultivar GA 10 showed\\u000a higher, IGP 76 and No. 71 moderate, and

S. G. Ghane; V. H. Lokhande; T. D. Nikam


Prediction of micro-bubble dissolution characteristics in water and seawater  

SciTech Connect

This paper is concerned with the prediction of micro-bubble dissolution characteristics in water and seawater when microbubbles are generated by a Sadatomi-type micro-bubble generator (2003) with a spherical body in a flowing liquid tube. In the experiments, in order to know the effects of the salinity on the characteristics, tap water and an artificial seawater with different salt concentrations of 1 and 3 wt% were used as the test liquids. Parameters measured were the Sauter mean diameter of bubbles, d{sub BS}, the void fraction, {alpha}, the rising velocity of bubbles, u{sub G}, the interfacial area concentration, a, the volumetric mass transfer coefficient, K{sub L}a, and the liquid-side mass transfer coefficient, K{sub L}. In the analysis, for predicting {alpha}, K{sub L}a and K{sub L}, some correlations in the literatures were tested against the present data. Furthermore, in order to improve the predictability, new correlations were developed based on the present data. The prediction of K{sub L}a with the new correlation agreed well with Nishino et al.'s [T. Nishino, K. Terasaka, M. Ishida, Application for several micro-bubble generators for gas absorber, in: Proceedings of the Annual Meeting of the Japanese Society for Multiphase Flow, 2006, pp. 276-277 (in Japanese)] and Li and Tsuge's [P. Li, H. Tsuge, Water treatment by induced air flotation using microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 896-903; P. Li, H. Tsuge, Ozone transfer in a new gas-induced contactor with microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 1213-1220] data for different aeration systems using several different micro-bubble generators. (author)

Kawahara, Akimaro; Sadatomi, Michio; Matsuura, Hidetoshi; Tominaga, Mayo; Noguchi, Masanori [Department of Mechanical System Engineering, Kumamoto University, Kurokami 2-39-1, Kumamoto City 860-8555 (Japan); Matsuyama, Fuminori [Department of Mechanical Engineering, Sasebo National College of Technology (Japan)



Physico-chemical and microbiological characteristics of water for fish production using small ponds  

NASA Astrophysics Data System (ADS)

The physical-chemical and biological characteristics of water in fish ponds were investigated with a view to optimise the conditions for fish productivity using small ponds. Five fish ponds were used in the study. The water samples were collected in each pond at a depth of 10-15 cm from the surface over a period of six months and analysed for pH, temperature, DO, alkalinity. The fish activity and growth rates were also assessed. The results showed that the ponds were slightly acidic to neutral (pH 6.69-7.66). The mean lowest and highest values of DO were 9.05 and 9.93 mg/L while the values for alkalinity were 67.86 and 90.57 mg/L respectively. The bacterial counts were in the order of 10 6 and the populations comprised Pseudomonas, Enterobacter, Salmonella, Staphylococcus, Bacillus, Azotobacter, Arthrobacter species and Escherichia coli. It was also observed that the fish activity increased as the temperature of the water varied from April to September as given by the activity ranges of 55-95, 40-80, 55-80, 70-95 and 55-95/m 2 for ponds P1, P2, P3, P4 and P5, respectively. The lowest values were in the months of April, May and June and highest values were in the months of July, August and September. The optimum conditions for increased fish productivity were found to be the warm temperatures (20 < t < 30 °C), adequate DO level (>4 mg/L) and appropriate pH (6 < pH < 9) and alkalinity (Alk) (80 < Alk < 200 mg/L). The correlations between characteristics were significant at 0.01 and 0.05 levels (2 tailed). Therefore, the fish productivity can be enhanced if the conditions in the ponds were maintained at optimum levels.

Ntengwe, Felix W.; Edema, Mojisola O.


[UV-Vis spectrum characteristics of phycocyanin in water from Taihu lake].  


The present paper analyzed the UV-Vis spectrum characteristics of phycocyanin extracted from 75 water samples around Meiliang Bay of Taihu Lake, China in spring, summer and autumn, 2011, taking standard sample of phycocyanin, Micro-cystic aeruginosa and Anabaena cultured indoor as the reference, and discussed the difference and relation of spectrum among water samples, standard sample and single algae samples. According to the number of absorption peak in the wavelength range from 500 to 700 nm, phycocyanin spectrum of water sampling in Taihu Lake can be divided into three patterns: no peak, single peak and two peaks. In the first pattern, the absorbance changed smoothly and no absorption peak was observed around 620 nm. Depending on the absorption difference in the wavelength range from 300 to 450 nm, this pattern can be divided into type I and type II. Type I only had a absorption peak near 260 nm, with the similar spectrum of chromophoric dissolved organic matter (CDOM) in the wavelength range from 250 to 800 nm. Type II had absorption peak respectively near 260 and 330 nm. In single peak pattern and two peaks pattern, significant absorption peak of phycocyanin appeared around 620 nm. Compared to the other patterns, single peak pattern was more similar to that of standard sample and single algae samples, but different in their maximum absorption peaks position and relative absorption intensity in the wavelength range of 250 approximately 300, 300 approximately 450 and 500 approximately 700 nm, because of different algae species and purity after extraction. In the two peaks pattern, another absorption peak appeared at 670nm, with the absorption shoulder from 350 to 450 nm, and shared the absorption characteristics of phycocyanin and chlorophyll complex protein. The research can provide a basic support for the phycocyanin quantitation and blooms monitoring in Taihu Lake. PMID:25095426

Zhang, Jing; Wei, Yu-Chun; Wang, Guo-Xiang; Cheng, Chun-Mei; Xia, Xiao-Rui




PubMed Central

Stocks, Peter K. (Louisiana State University, Baton Rouge), and C. S. McCleskey. Morphology and physiology of Methanomonas methanooxidans. J. Bacteriol. 88:1071–1077. 1964.—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 Methanomonas methanooxidans of Brown and Strawinski. Two of the isolates were serologically related to the organism of Brown and Strawinski. All the strains required methane for good growth, but a delayed moderate growth occurred on methanol. No other substances were utilized as carbon and energy source. Nitrogen requirements were satisfied by nitrates, ammonium salts, peptone, or certain amino acids. The taxonomic position of the species is discussed. Images PMID:14219021

Stocks, Peter K.; McCleskey, C. S.



The Characteristic of Porous Charges on a Base of a Water-Filled RDX Powder  

NASA Astrophysics Data System (ADS)

A detonation velocity of a condensed RDX linearly depends on density at a range of 1,0-1,8 g/cm^3. These charges are porous if the density of RDX monocrystal is 1,806 g/cm^3. The state of porous charge can be characterized by the packing density. It can be rising, if RDX powder will be mixed with water for deciding technological problems. It is necessary to be able to predict characteristics of such charges. Charges on a base of a water-filled RDX powder with air inclusions can be described by three parameters: a density of a charge, packing density of RDX powder and RDX mass fraction. Last two parameters are independent parameters of a mix. We have designed a nomogram for definition of mutual communication of three quantities: velocity of a detonation, density of packing of RDX powder and its mass fraction in a mix. To check up correctness of a prelegends of a nomogram, we have carried out measurement of a detonation velocity of porous water-contained RDX charges. We prepared charges on a base of RDX powder which has consisted of particles with a size 80-220 mcm. We was changing RDX mass fraction of charges in a range 0,6-1,0 and a packing density of RDX powder in a range of 1,0-1,4 g/cm^3. The disorder of experimental data concerning the nomogram data did not exceed basically of 3 percent.

Valiano, Georgy; Yankovskiy, Boris; Milyavskiy, Vladimir; Borodina, Tatiana



Physical characteristics and antioxidant effect of polysaccharides extracted by boiling water and enzymolysis from Grifola frondosa.  


Grifola frondosa has been widely consumed in China and other Asian countries. Recent studies on G. frondosa have focused on the activities of polysaccharides extracted by water, and the activities of polysaccharides extracted by enzymolysis have not been studied. In this work, the relationship between the physical properties and antioxidant activity of polysaccharides extracted from G. frondosa by boiling water and enzymolysis was studied. Five polysaccharide extracts from the fruit body of G. frondosa were prepared by different extracting methods including boiling water, single enzyme enzymolysis with three different single enzymes (cellulose, pectinase, and pancreatin), and combined enzyme enzymolysis (cellulose:pectinase:pancreatin; 2:2:1). Characteristics such as the viscosity, Mw, polysaccharide content, protein content, infrared spectra, and antioxidant activities of the extracts were evaluated. The highest antioxidant activity was exhibited by the extracts prepared by combined enzyme extraction. The correlation analysis between antioxidant activity and polysaccharide content, protein content, Mw or viscosity indicated that the Mw had a more important role in antioxidant activity. Overall, the results indicate that the combined enzyme polysaccharide extracts can be developed as a new potential natural antioxidant. PMID:21458482

Fan, Yina; Wu, Xiangyang; Zhang, Min; Zhao, Ting; Zhou, Ye; Han, Liang; Yang, Liuqing



Water-ethylene glycol cationic dimeric micellar solutions: aggregation, micellar growth, and characteristics as reaction media.  


Effects of ethylene glycol (EG) addition on the micellization and on the micellar growth in two aqueous didodecyl dicationic dibromide surfactant, 12-s-12,2Br- (s=2, 6) solutions, with the weight percentage of EG up to 50%, have been investigated. An increment in the amount of EG makes the aggregation process less spontaneous due to the water-EG mixtures being better solvents for the cationic dimeric surfactant molecules than pure water (solvophobic effect). Results show that C*, the surfactant concentration where the sphere-to-rod transition occurs, increases when EG content in the bulk phase increases. The amount of the organic solvent influences C* principally through the decrease in the hydrocarbon/bulk phase interfacial tension (air/bulk phase surface tension) caused by its presence. Changes in the aggregation number, in the micropolarity, in the microviscosity, and in the rheological behavior accompanying micellar growth were studied in the water-EG micellar solutions. Kinetic studies provide information about the characteristics of the dimeric micelles as microreactors. Kinetic data also show that an increase in the surfactant concentration leads to micellar growth. PMID:19422254

Rodríguez, Amalia; del Mar Graciani, María; Cordobés, Felipe; Moyá, María Luisa



Soil water repellency characteristic curves for soil profiles with natural organic carbon gradients  

NASA Astrophysics Data System (ADS)

Soil water repellency (SWR) is a phenomenon that influences many soil hydrologic processes such as reduction of infiltration, increase in overland flow, and enhanced preferential flow. SWR has been observed in various soil types and textures, and the degree of SWR is greatly controlled by soil moisture content and levels of organic matter and clay. One of the key topics in SWR research is how to describe accurately the seasonal and temporal variation of SWR with the controlling factors such as soil moisture, organic matter, and clay contents for soil profiles with natural organic carbon gradients. In the present study, we summarize measured SWR data for soil profiles under different land uses and vegetation in Japan and New Zealand, and compared these with literature data. We introduce the contact angle-based evaluation of SWR and predictive models for soil water repellency characteristic curves, in which the contact angle is a function of the moisture content. We also discuss a number of novel concepts, including i) the reduction in the contact angle with soil-water contact time to describe the time dependence of SWR, ii) the relationship between the contact angles from the measured scanning curves under controlled wetting and drying cycles, and iii) the initial contact angles measured by the sessile drop method.

Kawamoto, Ken; Müller, Karin; Moldrup, Per; de Jonge, Lis; Clothier, Brent; Hiradate, Syuntaro; Komatsu, Toshiko



Impact of catchment geophysical characteristics and climate on the regional variability of dissolved organic carbon (DOC) in surface water.  


Dissolved organic carbon (DOC) is a recognized indicator of natural organic matter (NOM) in surface waters. The aim of this paper is twofold: to evaluate the impact of geophysical characteristics, climate and ecological zones on DOC concentrations in surface waters and, to develop a statistical model to estimate the regional variability of these concentrations. In this study, multilevel statistical analysis was used to achieve three specific objectives: (1) evaluate the influence of climate and geophysical characteristics on DOC concentrations in surface waters; (2) compare the influence of geophysical characteristics and ecological zones on DOC concentrations in surface waters; and (3) develop a model to estimate the most accurate DOC concentrations in surface waters. The case study involved 115 catchments from surface waters in the Province of Quebec, Canada. Results showed that mean temperatures recorded 60 days prior to sampling, total precipitation 10 days prior to sampling and percentages of wetlands, coniferous forests and mixed forests have a significant positive influence on DOC concentrations in surface waters. The catchment mean slope had a significant negative influence on DOC concentrations in surface waters. Water type (lake or river) and deciduous forest variables were not significant. The ecological zones had a significant influence on DOC concentrations. However, geophysical characteristics (wetlands, forests and slope) estimated DOC concentrations more accurately. A model describing the variability of DOC concentrations was developed and can be used, in future research, for estimating DBPs in drinking water as well evaluating the impact of climate change on the quality of surface waters and drinking water. PMID:24911773

Cool, Geneviève; Lebel, Alexandre; Sadiq, Rehan; Rodriguez, Manuel J



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


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



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

stress; (b) to correlate solute accumulation with osmotic adjustment; (c) to determine whether there are physiological differences at the cellular level between drought-tolerant (DT) and drought-susceptible (DS) sorghum cultivars. A DT and a DS... conditions measured over 7 weeks. Data adjusted for PEG. 64 Fructose content (yg/mg DW) of DT and DS calli (2 reylicates) under stressed and non- stressed conditions measured over 7 weeks. Data adjusted for PEG. 15 17 18 Maltose content (pg/mg DW...

Diquez, Ricardo



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.



Fractal physiology  

Microsoft Academic Search

The nature of fractals and the use of fractals instead of classical scaling concepts to describe the irregular surfaces, structures, and processes exhibited by physiological systems are described. The mathematical development of fractals is reviewed, and examples of natural fractals are cited. Relationships among power laws, noise, and fractal time signals are examined

William Deering; Bruce J. West



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


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



Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention.  


Fluorine is the world's 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1 ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed. PMID:24719570

Peckham, Stephen; Awofeso, Niyi



The importance of the ionic product for water to understand the physiology of the acid-base balance in humans.  


Human plasma is an aqueous solution that has to abide by chemical rules such as the principle of electrical neutrality and the constancy of the ionic product for water. These rules define the acid-base balance in the human body. According to the electroneutrality principle, plasma has to be electrically neutral and the sum of its cations equals the sum of its anions. In addition, the ionic product for water has to be constant. Therefore, the plasma concentration of hydrogen ions depends on the plasma ionic composition. Variations in the concentration of plasma ions that alter the relative proportion of anions and cations predictably lead to a change in the plasma concentration of hydrogen ions by driving adaptive adjustments in water ionization that allow plasma electroneutrality while maintaining constant the ionic product for water. The accumulation of plasma anions out of proportion of cations induces an electrical imbalance compensated by a fall of hydroxide ions that brings about a rise in hydrogen ions (acidosis). By contrast, the deficiency of chloride relative to sodium generates plasma alkalosis by increasing hydroxide ions. The adjustment of plasma bicarbonate concentration to these changes is an important compensatory mechanism that protects plasma pH from severe deviations. PMID:24877130

Adeva-Andany, María M; Carneiro-Freire, Natalia; Donapetry-García, Cristóbal; Rañal-Muíño, Eva; López-Pereiro, Yosua



Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention  

PubMed Central

Fluorine is the world's 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1?ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed. PMID:24719570



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.



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



Effects of Micro/Nano-Scale Surface Characteristics on the Leidenfrost Point Temperature of Water  

NASA Astrophysics Data System (ADS)

In recent film boiling heat transfer studies with nanofluids, it was reported that deposition of nanoparticles on a surface significantly increases the nominal minimum heat flux (MHF) or Leidenfrost Point (LFP) temperature, considerably accelerating the transient cooling of overheated objects. It was suggested that the thin nanoparticle deposition layer and the resulting changes in the physico-chemical characteristics of the hot surface, such as surface roughness height, wettability and porosity, could greatly affect quenching phenomena. In this study, a set of water-droplet LFP tests are conducted using custom-fabricated surfaces which systemically separate the effects of surface roughness height (0-15 um), wettability (0-83°) and nanoporosity (?23 nm). In addition, high-speed imaging of the evaporating droplets is used to explore the influence of these surface characteristics on the intermittent solid-liquid contacts in film boiling. The obtained results reveal that nanoporosity (not solely high surface wettability) is the crucial feature in efficiently increasing the LFP temperature by initiating heterogeneous nucleation of bubbles during short-lived solid-liquid contacts, which results in disruption of the vapor film, and that micro-posts on the surface intensify such effects by promoting intermittent liquid-surface contacts.

Kim, Hyungdae; Truong, Bao; Buongiorno, Jacopo; Hu, Lin-Wen


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.



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.



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



Marine plastic pollution in waters around Australia: characteristics, concentrations, and pathways.  


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



Statistical characteristics of evaporating-freezing process of water droplet during quick depressurization  

NASA Astrophysics Data System (ADS)

This work investigates experimentally flashing evaporation process of water droplets released into vacuum, particularly on the quantitative characteristics of the process, in order to reveal the influences of the randomicity of the sub-process of nucleation and non-condensable air dissolved inside the liquid. It's clearly shown that nucleation time is a random variable. That may be caused by the following facts that nucleation for ice in high-supercooled water exhibits a strong randomicity and that there exists strong perturbation during quick depressurization. Freezing temperature of liquid droplet is approximately constant after recalescence, which may be determined by the vapor partial pressure at the terminal state. Freezing time is independent of nucleation time, but exhibits an obvious dependence on terminal pressure and drop diameter. Supercooling corresponding to the nucleation is independent of terminal pressure. The averaged values of supercooling at three different terminal pressures of 450, 600 and 1000 Pa are the same, namely 10 K. Furthermore, the influences of non-condensable gases on the process are analyzed and discussed in detail based on the experimental observations.

Du, Wang-Fang; Zhao, Jian-Fu; Li, Kai



Structural and spectroscopic characteristics of bacteriorhodopsin in air-water interface films.  


A suspension of purple membrane fragments in a solution of soya phosphatidyl-choline in hexane is spread at an air-water interface. Surface pressure and surface potential measurements indicate that the membrane fragments and lipids organize at the interface as an insoluble film. Electron microscopy of shadow-cast replicas of the film reveal that in the bacteriorhodopsin to soya PC weight ratio range of 2:1 to 10:1, these films consist of nonoverlapping membrane fragments which occupy approximately 35% of the surface area and are separated by a lipid monolayer. Furthermore, the membrane fragments are oriented with their intracellular surface towards the aqueous subphase. Nearly all the bacteriorhodopsin molecules at the interface are spectroscopically intact and exhibit visible spectral characteristics identical to those in aqueous suspensions of purple membrane and in intact bacteria. In addition, bacteriorhodopsin in air-dried interface films show spectral changes upon dark-adaptation and upon flash illumination similar to those observed in aqueous suspensions of purple membrane, but with slower kinetics. The kinetics of the spectral changes in interface films can be made nearly the same as in aqueous suspension by immersing the films in water. PMID:561850

Hwang, S B; Korenbrot, J I; Stoeckenius, W



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



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



Muscle Physiology  

NSDL National Science Digital Library

The Muscle Physiology Lab at the University of California-San Diego provides this comprehensive source of information on the neuromuscular system. The Web site appears as a extensive menu of subtopics, each leading to pages of detailed text and diagrams. Students studying muscle structure and function should find this well-organized and authoritative resource extremely useful. The Web site also includes a search tool for quickly finding pages of interest, and a list of related links for additional information.



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


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



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.



Insights into the Physiology and Ecology of the Brackish-Water-Adapted Cyanobacterium Nodularia spumigena CCY9414 Based on a Genome-Transcriptome Analysis  

PubMed Central

Nodularia spumigena is a filamentous diazotrophic cyanobacterium that dominates the annual late summer cyanobacterial blooms in the Baltic Sea. But N. spumigena also is common in brackish water bodies worldwide, suggesting special adaptation allowing it to thrive at moderate salinities. A draft genome analysis of N. spumigena sp. CCY9414 yielded a single scaffold of 5,462,271 nucleotides in length on which genes for 5,294 proteins were annotated. A subsequent strand-specific transcriptome analysis identified more than 6,000 putative transcriptional start sites (TSS). Orphan TSSs located in intergenic regions led us to predict 764 non-coding RNAs, among them 70 copies of a possible retrotransposon and several potential RNA regulators, some of which are also present in other N2-fixing cyanobacteria. Approximately 4% of the total coding capacity is devoted to the production of secondary metabolites, among them the potent hepatotoxin nodularin, the linear spumigin and the cyclic nodulapeptin. The transcriptional complexity associated with genes involved in nitrogen fixation and heterocyst differentiation is considerably smaller compared to other Nostocales. In contrast, sophisticated systems exist for the uptake and assimilation of iron and phosphorus compounds, for the synthesis of compatible solutes, and for the formation of gas vesicles, required for the active control of buoyancy. Hence, the annotation and interpretation of this sequence provides a vast array of clues into the genomic underpinnings of the physiology of this cyanobacterium and indicates in particular a competitive edge of N. spumigena in nutrient-limited brackish water ecosystems. PMID:23555932

Voß, Björn; Bolhuis, Henk; Fewer, David P.; Kopf, Matthias; Möke, Fred; Haas, Fabian; El-Shehawy, Rehab; Hayes, Paul; Bergman, Birgitta; Sivonen, Kaarina; Dittmann, Elke; Scanlan, Dave J.; Hagemann, Martin; Stal, Lucas J.; Hess, Wolfgang R.



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


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



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.


Effect of nozzle geometry for swirl type twin-fluid water mist nozzle on the spray characteristic  

Microsoft Academic Search

Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle\\u000a image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers\\u000a designed two types of swirl angles such as 0°, 90° and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm\\u000a were employed. The experiments were carried

Soon Hyun Yoon; Do Yeon Kim; Dong Keon Kim; Bong Hwan Kim



Use of proteomics and physiological characteristics to elucidate ecotoxic effects of methyl tert-butyl ether in Pseudomonas putida KT2440.  


We monitored rates of growth, ATP-synthesis, respiration, and death to assess the sensitivity of the model organism Pseudomonas putida KT2440 to methyl tert-butyl ether (MTBE), and its degree of toxicity. The physiological data obtained suggested that the energy conservation system was the most sensitive site. However, with the help of proteomic analysis we obtained further information and deeper insight into the molecular mechanisms involved. This analysis indicated that sensitivity involves oxidative stress since alkylhydroperoxide reductase C (AhpC) and two superoxide dismutases (SodM, SodF) were amplified in the presence of MTBE. Thus, proteomics has major advantages in ecotoxicological investigations where the aims include elucidation of the molecular mechanisms as well as characterization of the ecostress and the potency of the stressor(s). PMID:12923780

Krayl, Martin; Benndorf, Dirk; Loffhagen, Norbert; Babel, Wolfgang



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

E-print Network

Water management studies in PEM fuel cells, part III: Dynamic breakthrough and intermittent Water management Gas diffusion layer Water transport Dynamic breakthrough Intermittent drainage a b). In this work, the liquid water breakthrough dynamics, characterized by the capillary pressure and water

Kandlikar, Satish


[Effects of spatial coupling of watering and fertilization on winter wheat photosynthetic characteristics and grain yield].  


A soil column experiment was conducted with a fertile Eum-Orthic Anthrosols to study the effects of spatial coupling of watering and nitrogen (N)- and phosphorus (P) fertilization on the photosynthetic characteristics and grain yield of winter wheat. The column consisted of three layers, each layer being 30 cm in thickness and with an underlying 2 cm layer of coarse sand to obstruct water- and nutrient exchange. The results showed that relative content of chlorophyll (SPAD), net photosynthetic rate (P(n)), and grain yield were significantly lower in the treatment of 0-30 cm soil drought and 30-90 cm soil wetness (D) than in that of 0-90 cm soil wetness (W). In these two watering treatments, a combined application of N and P got the highest SPAD, P(n) and grain yield, followed by applying P, and N. The SPAD, P(n) and grain yield were significantly higher when the fertilizer N was applied in 0-90 cm layer than in 0-30, 30-60 and 60-90 cm layers, respectively. No significant differences in SPAD, P(n) and grain yield were observed when fertilizer P was applied in 0-90 cm layer and in 0-30 cm layer. In treatment W, the SPAD, P(n) and grain yield were the highest when N and P were applied in 0-90 cm layer, had no significant differences with those when the N and P were applied in 0-30 cm layer, but were significantly higher than those when the fertilization was carried out in 30-60 and 60-90 cm layers. In treatment D, no significant difference in SPAD was observed when the N and P were applied in different layers, but P(n) and grain yield were significant higher when the N and P were applied in 0-90 cm than in 30-60 cm layer, and in 30-60 cm than in 60-90 cm layer. It was concluded that whether in treatment W or in treatment D, a combined application of N and P should be carried out in 0-30 cm soil layer. PMID:18163307

Shen, Yu-Fang; Li, Shi-Qing; Shao, Ming-An



Renal Water Molecular Diffusion Characteristics in Healthy Native Kidneys: Assessment with Diffusion Tensor MR Imaging  

PubMed Central

Background To explore the characteristics of diffusion tensor imaging (DTI) and magnetic resonance (MR) imaging in healthy native kidneys. Methods Seventy-three patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar (SE-EPI) sequences accompanied by an array spatial sensitivity encoding technique (ASSET). Cortical and medullary mean, axial and radial diffusivity (MD, AD and RD), fractional anisotropy (FA) and primary, secondary and tertiary eigenvalues (?1, ?2, ?3) were analysed in both kidneys and in different genders. Results Cortical MD, ?2, ?3, and RD values were higher than corresponding medullary values. The cortical FA value was lower than the medullary FA value. Medullary ?1 and RD values in the left kidney were lower than in the right kidney. Medullary ?2, and ?3 values in women were higher than those in men. Medullary FA values in women were lower than those in men. Medullary FA (r?=?0.351, P?=?0.002) and ?1 (r?=?0.277, P?=?0.018) positively correlated with eGFR. Medullary FA (r?=??0.25, P?=?0.033) negatively correlated with age. Conclusions Renal water molecular diffusion differences exist in human kidneys and genders. Age and eGFR correlate with medullary FA and primary eigenvalue. PMID:25470776

Zheng, Zhenfeng; Shi, Huilan; Zhang, Jing; Zhang, Yunting



Statistical characteristics of cloud variability. Part 1: Retrieved cloud liquid water path at three ARM sites  

NASA Astrophysics Data System (ADS)

characteristics of cloud variability are examined for their dependence on averaging scales and best representation of probability density function with the decade-long retrieval products of cloud liquid water path (LWP) from the tropical western Pacific (TWP), Southern Great Plains (SGP), and North Slope of Alaska (NSA) sites of the Department of Energy's Atmospheric Radiation Measurement Program. The statistical moments of LWP show some seasonal variation at the SGP and NSA sites but not much at the TWP site. It is found that the standard deviation, relative dispersion (the ratio of the standard deviation to the mean), and skewness all quickly increase with the averaging window size when the window size is small and become more or less flat when the window size exceeds 12 h. On average, the cloud LWP at the TWP site has the largest values of standard deviation, relative dispersion, and skewness, whereas the NSA site exhibits the least. Correlation analysis shows that there is a positive correlation between the mean LWP and the standard deviation. The skewness is found to be closely related to the relative dispersion with a correlation coefficient of 0.6. The comparison further shows that the lognormal, Weibull, and gamma distributions reasonably explain the observed relationship between skewness and relative dispersion over a wide range of scales.

Huang, Dong; Campos, Edwin; Liu, Yangang



The Use of Bacterial Adherence to Hydrocarbons (BATH) Assay in Evaluation of the Hydrophobic Surface Characteristics of Potential Water Pathogens  

EPA Science Inventory

Bacterial adherence to hydrocarbons, BATH, is a method for determining the hydrophobic surface characteristics of bacterial cells. The strain?s affinity for water is evaluated by thoroughly mixing a culture and hydrocarbon suspension and then evaluating the decrease in optical de...


Hydrogeological and water quality characteristics of the saturated zone beneath the various land uses in the Nile Delta region, Egypt  

Microsoft Academic Search

The Nile Delta saturated zone lies beneath several land uses which reflect variations in the aquifer characteristics within the delta basin. The present study investigates the scattered rural and urban areas and their environmental impacts on the water quality of the underlying semi-confined and unconfined aquifer systems. The agricultural and industrial activities also affect the groundwater quality located close to




Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this research was to determine characteristics of soil water extractable organic matter (WEOM) under different land uses in a subarctic environment. Soil (Volkmar, Aquic Eutrocrepts) samples were taken in October, 2005 from forestry, agricultural, and USDA Conservation Reserve Prog...


Physical and chemical characteristics of ultrasonically-prepared water-in-diesel fuel: effects of ultrasonic horn position and water content.  


An ultrasonic technique was applied to preparation of two-phase water-in-oil (W/O) emulsified fuel of water/diesel oil/surfactant. In this study, an ultrasonic apparatus with a 28 kHz rod horn was used. The influence of the horn tip position during ultrasonic treatment, sonication time and water content (5 or 10 vol%) on the emulsion stability, viscosity, water droplet size and water surface area of emulsion fuels prepared by ultrasonication was investigated. The emulsion stability of ultrasonically-prepared fuel significantly depended on the horn tip position during ultrasonic irradiation. It was found that the change in the stability with the horn tip position was partly related to that in the ultrasonic power estimated by calorimetry. Emulsion stability, viscosity and sum of water droplets surface area increased and water droplet size decreased with an increase in sonication time, and they approached each limiting value in the longer time. The maximum values of the viscosity and water surface area increased with water content, while the limiting values of the emulsion stability and water droplet size were almost independent of water content. During ultrasonication of water/diesel oil mixture, the hydrogen and methane were identified and the cracking of hydrocarbon components in the diesel oil occurred. The combustion characteristics of ultrasonically-prepared emulsion fuel were studied and compared with those of diesel oil. The soot and NOx emissions during combustion of the emulsified fuel with higher water contents were significantly reduced compared with those during combustion of diesel oil. PMID:24207138

Kojima, Yoshihiro; Imazu, Hiroki; Nishida, Keiichi



Environmental characteristics and water quality of hydrologic benchmark network stations in the Eastern United States, 1963-95  

USGS Publications Warehouse

The information in this report was compiled to aid in the application and interpretation of historical water-quality data collected as part of the U.S. Geological Survey Hydrologic Benchmark Network program, which was established in 1963 to provide long-term measurements of streamflow and water quality in areas that are minimally affected by human activities. This report describes the environmental characteristics and water quality at 16 benchmark basins in the Eastern United States. In most of the basins, stream-water chemistry seems to be controlled by the interaction of acidic precipitation with the underlying soils and bedrock. Land use had a minimal effect on stream-water chemistry at most of the gaging stations.

Mast, M. Alisa; Turk, John T.



Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations - Method, validation, and data characteristics  

NASA Technical Reports Server (NTRS)

Results are presented of water vapor observations in the troposphere and stratosphere performed by the Stratospheric Aerosol and Gas Experiment II solar occultation instrument, and the analysis procedure, the instrument errors, and data characteristics are discussed. The results are compared with correlative in situ measurements and other satellite data. The features of the data set collected between 1985 and 1989 include an increase in middle- and upper-tropospheric water vapor during northern hemisphere summer and autumn; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds.

Rind, D.; Chiou, E.-W.; Chu, W.; Oltmans, S.; Lerner, J.; Larsen, J.; Mccormick, M. P.; Mcmaster, L.



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.



Physiological adjustments of sand gazelles (Gazella subgutturosa) to a boom-or-bust economy: standard fasting metabolic rate, total evaporative water loss, and changes in the sizes of organs during food and water restriction.  


To test the hypothesis that desert ungulates adjust their physiology in response to long-term food and water restriction, we established three groups of sand gazelles (Gazella subgutturosa): one that was provided food and water (n = 6; CTRL) ad lib. for 4 mo, one that received ad lib. food and water for the same period but was deprived of food and water for the last 4.5 d (n = 6; EXPT(1)), and one that was exposed to 4 mo of progressive food and water restriction, an experimental regime designed to mimic conditions in a natural desert setting (n = 6; EXPT(2)). At the end of the 4-mo experiment, we measured standard fasting metabolic rate (SFMR) and total evaporative water loss (TEWL) of all sand gazelles and determined lean dry mass of organs of gazelles in CTRL and EXPT(2). Gazelles in CTRL had a mean SFMR of 2,524 +/- 194 kJ d(-1), whereas gazelles in EXPT(1) and EXPT(2) had SFMRs of 2,101+/- 232 and 1,365 +/- 182 kJ d(-1), respectively, values that differed significantly when we controlled for differences in body mass. Gazelles had TEWLs of 151.1 +/- 18.2, 138.5 +/- 17.53, and 98.4 +/- 27.2 g H(2)O d(-1) in CTRL, EXPT(1), and EXPT(2), respectively. For the latter group, mass-independent TEWL was 27.1% of the value for CTRL. We found that normally hydrated sand gazelles had a low mass-adjusted TEWL compared with other arid-zone ungulates: 13.6 g H(2)O kg(-0.898) d(-1), only 17.1% of allometric predictions, the lowest ever measured in an arid-zone ungulate. After 4 mo of progressive food and water restriction, dry lean mass of liver, heart, and muscle of gazelles in EXPT(2) was significantly less than that of these same organs in CTRL, even when we controlled for body mass decrease. Decreases in the dry lean mass of liver explained 70.4% of the variance of SFMR in food- and water-restricted gazelles. As oxygen demands decreased because of reduced organ sizes, gazelles lost less evaporative water, probably because of a decreased respiratory water loss. PMID:16826507

Ostrowski, Stephane; Mesochina, Pascal; Williams, Joseph B



Responses of Fraxinus excelsior L. seedlings to ambient ozone exposure in urban and mountain areas based on physiological characteristics and antioxidant activity.  


Effects of ozone on the sensitive tree species Fraxinus excelsior L. exposed to ambient air were investigated. The dynamics of photosynthesis, transpiration, stomatal conductance and the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in three-year-old ash seedlings were studied during a four-month period (June-September). Seedlings were exposed to ambient ozone in an urban (the Central City Park of Sofia - Borisova Gradina) and a mountain (Plana Mountain) area in Bulgaria. The sites were located near climate monitoring stations, providing data on ozone concentrations and meteorological parameters. Ozone exposure at the mountain site (AOT40) was more than two times higher compared to the urban site. Significantly higher values of sun radiation, transpiration, stomatal conductance and enzyme activity at the mountain site were also observed. At the urban site higher values of temperature and air humidity were registered. Effects of the measured variables on ash seedlings were complex and interdependent. No direct effect of ozone concentration in ambient air on the leaf physiology and biochemistry could be proved. However, intensified SOD and CAT activity in the presence of elevated ozone suggested antioxidant reaction in response to ozone uptake. PMID:23760537

Parvanova, Petya; Tzvetkova, Nikolina; Bratanova-Doncheva, Svetla; Chipev, Nesho; Fikova, Radka; Donev, Evgeni



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.



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



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.




EPA Science Inventory

Field investigations have been conducted to understand the fate of arsenic in contaminated ground water during discharge into a small lake. The ground water plume contains elevated levels of arsenic and BTEX compounds derived from historical disposal of process wastes from up gr...


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


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



Effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees.  


Trees can improve air quality by capturing particles in their foliage. We determined the particle capture efficiencies of coniferous Pinus sylvestris and three broadleaved species: Betula pendula, Betula pubescens and Tilia vulgaris in a wind tunnel using NaCl particles. The importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. The results confirm earlier findings of more efficient particle capture by conifers compared to broadleaved plants. The particle capture efficiency of P. sylvestris (0.21%) was significantly higher than those of B. pubescens, T. vulgaris and B. pendula (0.083%, 0.047%, 0.043%, respectively). The small leaf size of P. sylvestris was the major characteristic that increased particle capture. Among the broadleaved species, low leaf wettability, low stomatal density and leaf hairiness increased particle capture. Moderate soil drought tended to increase particle capture efficiency of P. sylvestris. PMID:23735814

Räsänen, Janne V; Holopainen, Toini; Joutsensaari, Jorma; Ndam, Collins; Pasanen, Pertti; Rinnan, Åsmund; Kivimäenpää, Minna



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


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



Profile characteristics during extended gravity drainage under falling water table conditions  

Microsoft Academic Search

A computer-based numerical analysis of the equation describing water movement in unsaturated porous materials is used to provide data on the shape of the water content profile and the thickness of the draining capillary fringe during extended gravity drainage when the water table is permitted to fall at a constant velocity to a considerable depth below the surface. These velocities

K. K. Watson



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



Physiological characteristics and stress resistance of great sturgeon (Huso huso) juveniles fed with vitamins C, E, and HUFA-enriched Artemia urmiana nauplii.  


This study was carried out to examine the effect of Artemia urmiana nauplii enriched with HUFA, and vitamins C and E on stress tolerance, hematocrit, and biochemical parameters of great sturgeon, Huso huso juveniles. Cod liver oil (EPA 18% and DHA 12%), ascorbyl-6-palmitate and alpha-tocopherol acetate were used as lipid, and vitamin C and E sources, respectively. Beluga juveniles at the stage of first feeding (69.7 +/- 5.9 mg body weight) were randomly divided into five treatments and three tanks were assigned to each diet. All fish groups were fed non-enriched Artemia for the initial 5 days and then fed enriched Artemia for 7 days. Juveniles were fed with Artemia enriched with HUFA + 20% vitamin C (C group); HUFA + 20% vitamin E-enriched Artemia nauplii (E group); HUFA + 20% vitamin C + 20% vitamin E (C and E group); HUFA without vitamins (HUFA) and non-enriched Artemia (control). After the period of enrichment, Juveniles were fed with Daphnia sp. from the 13th to the 40th day. At day 40, the fish were transferred directly from fresh water (0.5 ppt) to brackish water (6 ppt for 4 days and 12 ppt for 2 days) and warm water (from 27 to 33 degrees C) to evaluate juvenile resistance to salinity and thermal shocks. Moreover, all treatments were separately exposed to freshwater in tanks with the same capacity as used for osmotic and thermal tests (as fresh water control). The addition of vitamins C, E, and C + E to HUFA significantly increased fish resistance to 12 ppt salinity and temperature stress tests, whereas survival was not significantly different among challenges at 6 ppt. There was no significant difference in the hematocrit index under stress conditions. Enrichment had significant influence on plasma Na(+) level in the C group on the 4th day at 6 ppt. Na(+) and Ca(2+) concentrations in C, E, and C and E groups on the 1st day at 12 ppt, and Ca(2+) level in E group on the 2nd day at 12 ppt were lower than the other groups. The glucose level in the C and C and E groups was lower than the other treatments on the 1st day at 12 ppt and the 2nd day at 33 degrees C. Regardless of Artemia enrichment, plasma ions (Na(+), K(+), Ca(2+), and Mg(2+)) and glucose concentrations in fish exposed to salinity stress tests were higher than fish in fresh water. Glucose concentration in plasma also increased after 2 days at 33 degrees C. Although most of our results were not significantly different, the use of vitamins C, E, and HUFA in Artemia enrichment can improve Juveniles tolerance under stress conditions, and regardless of enrichment, these data show that beluga juveniles are partly sensitive to high salinity and temperature. PMID:19459059

Jalali, Mohammad Ali; Hosseini, Seyed Abbas; Imanpour, Mohammad Reza



Environmental loads from water-sprinkled softwood timber. 2: Influence of tree species and water characteristics on wastewater discharges  

SciTech Connect

The concentration patterns of a number of compounds in the inlet water and wastewater from sprinkling of timber from Scotch pine and Norway spruce have been studied. The timber was separated with respect to species and sprinkled with water from a eutrophic or an oligotrophic receiving water for 18 weeks. Organic and inorganic compounds including dissolved organic carbon (DOC), distillable phenols, resin acids, bacterial phospholipid fatty acids, organic and inorganic phosphorus, nitrogen and sulfur, and a number of metal ions were monitored in the inlet water and wastewater. The toxicity of the wastewater was estimated during the first 2 weeks using a Microtox{reg_sign} test and appeared to decline in parallel with DOC. Most compounds showed both an environmental net load and an absorption by the timber, the loads being smaller and the absorption larger when using eutrophic water. At both sites the loads were generally largest during the first 2 weeks and larger in magnitude at the oligotrophic site and in the spruce wastewater. The initial growth of the bacterial biomass in the pile system was slower at the oligotrophic site, and the results indicated that a rapid growth of the bacterial biomass reduces the initial environmental loads and that this process is associated with the nutrient status of the receiving water.

Borga, P.; Elowson, T.; Liukko, K. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)



Hydro-chemical characteristics of river water around Toyama bay and preliminary consideration of nitrate load toward the bay  

NASA Astrophysics Data System (ADS)

To understand hydro-chemical characteristics of river water and NO3--N load toward Toyama bay through the base flow. The hydrological field survey and analysis of inorganic ion chemistry, stable isotopic ratios of hydrogen and oxygen, and tritium activity in water samples were conducted for 25 rivers around Toyama bay. The isotopic ratio of river water in Toyama prefecture shows different content in comparison with that of Ishikawa prefecture, and water chemistry of small catchment rivers in western part of Toyama prefecture and Noto peninsula, except Kumabuchi and Sakiyama rivers, shows Na+-HCO3- type due to wind-borne chloride. As for the NO3--N load toward Toyama bay, the contribution of rivers with large catchment and the flow through the residential area is relatively large in both prefectures. The results suggested that the isotopic and geochemical characteristics of river water were related to the site of catchment, topographic feature, local geology, and major land use in the catchment area. The estimated annual total NO3--N load toward the bay through the base flow was about 4,200 tons.

Ikawa, Reo; Shimada, Jun; Tokunaga, Tomochika; Gotou, Jyunji


Environmental characteristics and water quality of hydrologic benchmark network stations in the Midwestern United States, 1963-95  

USGS Publications Warehouse

This report describes the environmental characteristics and water quality at 14 benchmark basins in the Midwestern United States. The information in this report was compiled to aid in the application and interpretation of historical water-quality data collected by the U.S. Geological Survey Hydrologic Benchmark Network program. The streams discussed in this report drain either forested areas or grasslands with a variety of land-use activities that range from recreational use, timber harvesting, and military training on publicly owned land to agriculture and residential development on privately owned land.

Mast, M. Alisa; Turk, John T.




EPA Science Inventory

Sorbent and solvent characteristics influencing sorption of pentachlorophenol (PCP) were investigated. Analysis of aqueous sorption data for several sorbents over a broad pH range suggested hydrophobic sorption of neutral PCP predominates at pH 7. At pH > 7, sorption of the penta...



EPA Science Inventory

Sorbent and solvent characteristics influencing sorption of pentachlorophenol (PCP) were investigated. nalysis of aqueous sorption data for several sorbents over a broad pH range suggested hydrophobic sorption of neutral PCP predominates at pH7, sorption of the pentachlo...


Experimental and analytical study of stability characteristics of natural circulation boiling water reactors during startup transient  

NASA Astrophysics Data System (ADS)

Two-phase natural circulation loops are unstable at low pressure operating conditions. New reactor design relying on natural circulation for both normal and abnormal core cooling is susceptible to different types of flow instabilities. In contrast to forced circulation boiling water reactor (BWR), natural circulation BWR is started up without recirculation pumps. The tall chimney placed on the top of the core makes the system susceptible to flashing during low pressure start-up. In addition, the considerable saturation temperature variation may induce complicated dynamic behavior driven by thermal non-equilibrium between the liquid and steam. The thermal-hydraulic problems in two-phase natural circulation systems at low pressure and low power conditions are investigated through experimental methods. Fuel heat conduction, neutron kinetics, flow kinematics, energetics and dynamics that govern the flow behavior at low pressure, are formulated. A dimensionless analysis is introduced to obtain governing dimensionless groups which are groundwork of the system scaling. Based on the robust scaling method and start-up procedures of a typical natural circulation BWR, the simulation strategies for the transient with and without void reactivity feedback is developed. Three different heat-up rates are applied to the transient simulations to study characteristics of the stability during the start-up. Reducing heat-up rate leads to increase in the period of flashing-induced density wave oscillation and decrease in the system pressurization rate. However, reducing the heat-up rate is unable to completely prevent flashing-induced oscillations. Five characteristic regions of stability are discovered at low pressure conditions. They are stable single-phase, flashing near the separator, intermittent oscillation, sinusoidal oscillation and low subcooling stable regions. Stability maps were acquired for system pressures ranging 100 kPa to 400 kPa. According to experimental investigation, the flow becomes stable below a certain heat flux regardless of the inlet subcooling at the core and system pressure. At higher heat flux, unstable phenomena were indentified within a certain range of inlet subcooling. The unstable region diminishes as the system pressure increases. In natural circulation BWRs, the significant gravitational pressure drop over the tall chimney section induces a Type-I instability. The Type-I instability becomes especially important during low power and pressure conditions during reactor start-up. Under these circumstances the effect of pressure variations on the saturation enthalpy becomes significant. An experimental study shows that the flashing phenomenon in the adiabatic chimney section is dominant during the start-up of a natural circulation BWR. Since flashing occurs outside the core, nuclear feedback effects on the stability are small. Furthermore, the thermal-hydraulic oscillation period is much longer than power fluctuation period caused by void reactivity feedback. In the natural circulation system increasing the inlet restriction reduces the natural circulation flow rate, shifting the unstable region to higher inlet subcooling.

Woo, Kyoungsuk


Improved characteristics of hydrophobic polytetrafluoroethylene–platinum catalysts for tritium recovery from tritiated water  

Microsoft Academic Search

This paper presents recent results concerning a new preparation method and characteristics of the hydrophobic catalysts used in hydrogen isotopes separation. The objectives of the paper are: (1) to assess the current status and find a new procedure for the preparation of a new improved hydrophobic catalyst; (2) to improve the characteristics and performance of platinum hydrophobic catalysts.As a result

I. Popescu; Gh. Ionita; I. Stefanescu; C. Varlam; D. Dobrinescu; I. Faurescu



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.



The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.  


Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15?mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20?mg/l) was broader than that of acid-soluble chitosan (4-8?mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien



Casein micelle dispersions into water, NaCl and CaCl 2: physicochemical characteristics of micelles and rennet coagulation  

Microsoft Academic Search

We have studied the effect of ionic strength from about 0 to 0.12m on physicochemical characteristics of micelles and on gelation by rennet. Native phosphocaseinate powder was used as it exhibits attractive technological properties. The powder was dissolved at 25gl?1 casein concentration with 0.2gl?1 sodium azide into deionised water, NaCl or CaCl2 solutions, at ionic strength from 0 to 0.12m.

M. H. Famelart; Y. Le Graet; K. Raulot




Microsoft Academic Search

Six research plots were established on a surface mine for the purpose of evaluating the forest productivity potential and hydrological and water quality characteristics of three different loose-graded spoil types. The three spoil types were: (1) predominately brown, weathered sandstone (BROWN); (2) predominately gray, un-weathered sandstone (GRAY); and (3) mixed weathered and un-weathered sandstones and shale material (MIXED). The average

Patrick N. Angel; Christopher D. Barton; Richard C. Warner; Carmen Agouridis; Tim Taylor; Sarah L. Hall


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



Surface water and groundwater characteristics in the wetlands of the Ajó River (Argentina)  

NASA Astrophysics Data System (ADS)

Intertidal wetlands are complex hydrological environments in which surface water and groundwater interact periodically with tidal flows. This work analyzes how the tidal flow determines the hydrodynamics and salinity of surface water and groundwater at different depths in the intertidal wetland located in the marsh of the Ajó River. Water level and salinity measurements were obtained from the Ajó River, the channels discharging into the river and the phreatic aquifer. The results in the natural marsh indicate the presence of saline stratification and that the surface water-groundwater relationship varies with the tide. At low tide, the water table discharges into the surface watercourses, and when the high tide rises above the regional groundwater discharge level, the tidal flow contributes to the water table, which causes an increase in salinity in surface water and groundwater. When the high tide does not rise above the discharge level, the tidal flow only enters the groundwater at the mouth section and the salinity of the surface water and groundwater decreases from low tide to high tide. In the marsh areas excluded from the tidal cycle due to the presence of floodgates, the water table always discharges into the canals, and in the surface water and groundwater there is no presence of saline stratification. The results obtained make it possible to generate a conceptual model of hydrological behaviour which shows the hydrodynamic and hydrochemical complexity of intertidal wetlands.

Carol, E. S.; Dragani, W. C.; Kruse, E. E.; Pousa, J. L.



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.



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.  


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?

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



Spatial distribution of leaf morphological and physiological characteristics in relation to local radiation regime within the canopies of 3-year-old Populus clones in coppice culture.  


Spatial distributions of leaf characteristics relevant to photosynthesis were compared within high-density coppice canopies of Populus spp. of contrasting genetic origin. We studied three clones representative of the range in growth potential, leaf morphology, coppice and canopy structure: Clone Hoogvorst (Hoo) (Populus trichocarpa Torr. & Gray x Populus deltoides Bartr. & Marsh), Clone Fritzi Pauley (Fri) (Populus trichocarpa Torr. & Gray) and Clone Wolterson (Wol) (Populus nigra L.). Leaf area index ranged from 2.7 (Fri and Wol) to 3.8 (Hoo). The clones exhibited large vertical variation in leaf area density (0.02-1.42 m2 m-3). Leaf dry mass per unit leaf area (DM(A)) increased with increasing light in Clones Hoo and Fri, from about 56 g m-2 at the bottom of the canopy to 162 g m-2 at the top. In Clone Wol, DM(A) varied only from 65 to 100 g m-2, with no consistent relationship with respect to light. Conversely, nitrogen concentration on a mass basis was nearly constant (around 1.3-2.1%) within the canopies of Clones Hoo and Fri, but increased strongly with light in Clone Wol, from 1.4% at the bottom of the canopy to 4.1% at the top. As a result, nitrogen per unit leaf area (N(A)) increased with light in the canopies of all clones, from 0.9 g m-2 at the bottom to 2.9 g m-2 at the top. Although a single linear relationship described the dependence of maximum carboxylation rate (17-93 micromol CO2 m-2 s-1) or electron transport capacity (45-186 micromol electrons m-2 s-1) on N(A), for all clones, Clone Wol differed from Clones Hoo and Fri by exhibiting a higher dark respiration rate at low N(A) (1.8 versus 0.8 micromol CO2 m-2 s-1). PMID:12490425

Casella, E; Ceulemans, R



Impact of acute water and feed deprivation events on growth performance, intestinal characteristics, and serum stress markers in weaned pigs.  


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



[Water impounding characteristics of bamboo-shaped rainwater harvesting ditch in the hilly loess region].  


Bamboo-shaped rainwater harvesting ditch (BRHD) is a new water harvesting and application technology being promoted in the hilly loess region of North Shannxi Province. This paper measured the soil moisture condition and water storage capacity of BRHDs filled with straw, branch or gravel through field and simulated rainfall experiments to evaluate the water holding and absorption capacity of different BRHD fillers. From May to October, the water storage of BRHDs showed a decrease trend at first and then increased in field experiment. The water storage depths within 30-200 cm profile of branch ditch (BD), gravel ditch (GD) and straw ditch (SD) were 186.76, 177.23 and 169.26 mm in May, respectively, and increased by 14.24, 20.28 and 21.23 mm in October, respectively. In contrast, the water storage depth of the level bench was reduced by 6.52 mm in October from 185.76 mm in May. The soil water restoration depth was different between BRHDs with different fillers and the level bench within 30-200 cm profile in October. The SD and BD had the deepest restoration depth (140 cm), followed by GD (110 cm), and the level bench was the minimum (80 cm). Through rainfall simulation experiment, the amount of water intercepted by BRHD was in the order of SD (99.5 L) > GD (91 L) > BD (71.5 L). The water-holding rate of straw and branch showed logarithmic function with soaking time, while the water-absorption rate followed a power function. Moreover, there was a negative logarithm correlation between water-holding rate and water-absorption rate. Straw showed a better water holding and absorption capacity than branch. Gravel had a weak water holding and absorption capacity which was almost not changed during soaking, while it displayed a negative liner correlation between water holding rate and absorption rate. The three kinds of BRHDs could be applied in the hilly loess region, and that filled with straw would exhibit the best capacity of water interception and holding. PMID:24697054

Lin, Jun; Wang, You-Ke; Wei, Xin-Dong; Xiao, Sen; Zhang, Xue



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.



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...


A Study of the Flow Characteristics in Air-Water Two-Phase Flow under Microgravity  

Microsoft Academic Search

Reliable design of space thermal management systems requires a through understanding of the hydrodynamic characteristics of two-phase flow influenced by the change in gravity. The data of flow patterns, void fraction, frictional pressure drop associated with its characteristics were obtained at normal gravity and in microgravity and hyper-gravity (2g) conditions aboard MU-300 aircraft capable of parabolic trajectory flying. Some experiments

Buhong Choi; Terushige Fujii; Hitoshi Asano; Katsumi Sugimoto



Effect of Non-condensable gas on Solutal Marangoni Condensation Heat Transfer Characteristics for Water-Ethanol Vapor Mixture  

NASA Astrophysics Data System (ADS)

The condensation heat transfer characteristic curves for ternary vapor mixture of water, ethanol and air (or nitrogen) under the ethanol mass fraction of 0.01, 0.07, 0.25, 0.45 and relatively low concentrations of air (or nitrogen) were measured.The effect of air (or nitrogen) as a non-condensable gas on several different domains in the Marangoni condensation characteristic curves was discussed. It was shown that the effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable but in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, the variations of the several characteristic points representing the characteristic curves caused by the change in non-condensable gas concentration were discussed. The deteriorations of the maximum heat transfer coefficient and the maximum heat flux for low ethanol concentration and low concentration of non-condensable gas, in which the excellent heat transfer characteristics were exhibited, were more remarkable.

Wang, Shixue; Utaka, Yoshio


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




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...


Occurrence and Removal Characteristics of Phthalate Esters from Typical Water Sources in Northeast China  

PubMed Central

The presence of phthalate esters (PAEs) in the environment has gained a considerable attention due to their potential impacts on public health. This study reports the first data on the occurrence of 15 PAEs in the water near the Mopanshan Reservoir—the new and important water source of Harbin city in Northeast China. As drinking water is a major source for human exposure to PAEs, the fate of target PAEs in the two waterworks (Mopanshan Waterworks and Seven Waterworks) was also analyzed. The results demonstrated that the total concentrations of 15 PAEs in the water near the Mopanshan Reservoir were relatively moderate, ranging from 355.8 to 9226.5?ng/L, with the mean value of 2943.1?ng/L. DBP and DEHP dominated the PAE concentrations, which ranged from 52.5 to 4498.2?ng/L and 128.9 to 6570.9?ng/L, respectively. The occurrence and concentrations of these compounds were heavily spatially dependent. Meanwhile, the results on the waterworks samples suggested no significant differences in PAE levels with the input of the raw waters. Without effective and stable removal of PAEs after the conventional drinking water treatment in the waterworks (25.8% to 76.5%), the risks posed by PAEs through drinking water ingestion were still existing, which should be paid special attention to the source control in the Mopanshan Reservoir and some advanced treatment processes for drinking water supplies. PMID:23577281

Liu, Yu; Chen, Zhonglin; Shen, Jimin



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



Shear deformation characteristics of single walled carbon nanotube with water interactions by using molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

The mechanical properties of single walled carbon nanotube (SWCNT) with water interactions are studied in this work using molecular dynamics simulation method. The elastic properties of carbon nanotubes (CNTs) in a biological/fluidic medium such as water are critical for its key role in determining the lifetime and stability of CNT based nano-fluidic devices. The effect of chirality, defects and the density of water encapsulation is studied by subjecting the SWCNT to shear loading. The findings show that the interaction of water molecules and defect density and distribution will reduce the mechanical strength of SWCNT. We also conducted studies on the mechanical response of free standing and water submerged capped SWCNTs filled with water molecules under axial shear loading. We find that the mechanical strength of the water encapsulated SWCNTs is affected by the density of water encapsulation. Our findings and conclusions obtained from this paper is expected to further compliment the potential applications of CNTs as promising candidates for applications in nano-biological and nano-fluidic devices.

Vijayaraghavan, V.; Wong, C. H.



Physicochemical Characteristics of Thermopylae Natural Hot Water Springs in Central Greece: Chemical Geothermometry  

Microsoft Academic Search

In this work, the temperature of the subsurface reservoir in the Thermopylae natural hot water springs in Central Greece is estimated using chemical geothermometry. For this purpose, a novel computational methodology is proposed. This methodology is based on the selection of the minerals which might be in equilibrium with the subsurface water in the reservoir. The selection of minerals is

G. D. Verros; T. Latsos; K. E. Anagnostou; P. Avlakiotis; C. Chaikalis; C. Liolios; D. Antoniou; S. Kotsopoulos; P. Arsenos



Water consumption characteristics and water use efficiency of winter wheat under long-term nitrogen fertilization regimes in northwest China.  


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



Transient formation characteristics of temperature stratified flow in a horizontal water pipe with an injection of hot water from a hole of a pipe  

SciTech Connect

Temperature stratified flow was numerically analyzed in a horizontal pipe. Initially cold water is running and developed in a pipe. From a part of a pipe wall, hot water is injected. Subsequent transient velocity and temperature stratification process was numerically analyzed. This process is a model for such transfer phenomena as follows, i.e., blowing of fresh air into a long tunnel, replacing process of hazardous fluids from a pipeline of an industrial plant with safer fluids, ventilation of a large construction house or ducts, transient combustion process in a tunnel or huge duct, transient flow and temperature characteristics in a canal or river with multiple sub channels. These various cases become more complicated and more serious for the larger scale systems. Temperature stratified flow is everywhere established which makes the prediction difficult. This paper presents transient three-dimensional numerical analyses for a horizontal pipe in which laminar cold water runs steadily. Hot water is injected from a lower side corner of a pipe. Model equations consist of fully three-dimensional balance equations in a cylindrical coordinate. Total tube length computed is 10 times of a pipe diameter d{sub 0}. Hot water inlet hole is 0.4d{sub 0} long in an axial direction and {pi}d{sub 0}/8 in a circumferential direction near the entrance of the system. Reynolds number in a pipe is 1000. Reynolds number of the hot water at the injection hole is 447. Grashof number based on the temperature difference is 5 x 10{sup 7} and Pr = 5.41. Transient three-dimensional velocity profiles and isotherms are presented. The instantaneous water temperature represents oscillatory fluctuation depending on the level in a pipe and on the axial distance from the injection hole. For the tube diameter 0.1m, an average temperature arrived a quasi-steady state after 5 minutes with strong temperature stratification even at 1m from an injection hole. Near the injection hole, hot water makes circumferential convection with oscillatory up and down vortex flow in an axial direction. Warmer water makes stratified flow with faster axial velocity near the top of the tube with much slower axial velocity near the bottom of the tube. These fully three-dimensionally complicated flow and temperature stratification characteristics are presented in various ends view and side views of a long pipe. The importance to note the temperature stratified flow is discussed.

Okinotani, Takeshi; Ozoe, Hiroyuki



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.



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.



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.



Abundance and characteristics of the recreational water quality indicator bacteria Escherichia coli and enterococci in gull faeces  

USGS Publications Warehouse

Aims: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal indicator bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. Methods and Results: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (Vitek?? GNI+) and enterococci (API?? rapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at ???85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus API?? profiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. Conclusions: Gull faeces could be a major contributor of E. coli (105-109 CFU g-1) and enterococci (104-108 CFU g-1) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. Significance and Impact of the Study: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.

Fogarty, L.R.; Haack, S.K.; Wolcott, M.J.; Whitman, R.L.



Analysis of the effect of wash water reduction on bleached pulp characteristics.  


The main objective of this study was to analyse cost reduction by reducing the use of fresh water in the cellulose bleaching process and to make it easier to obtain water in a closed circuit. Eucalyptus oxygen delignified industrial pulp was used. The pulp was bleached 10 times in the D(E+P)DP sequence in the same conditions. Counter current washing was used in the bleaching stages, and each sequence was carried out with different wash factors: 9, 6, 3, and 0?m³ of distilled water/ton of oven dry pulp. The goal was to reach brightness of 92?±?0.5% ISO. The results showed that there was a chemical oxygen demand (COD) increase and brightness reversion, but the kappa number and viscosity did not change. The apparent colour was increased by increasing COD in the effluent during the cycles and by decreasing the wash water. Up to 3?m³/t of water was tolerable and even recommended to wash pulp. Nine cubic metre per tonne of fresh water is most commonly used in the industry, so water savings make the implementation of the process possible. PMID:25204209

Frigieri, Tânia Cristina; Ventorim, Gustavo; Savi, Antônio Francisco; Favaro, Jaqueline Silveira Comelato



Study of physico-chemical characteristics of water bodies around Jaipur.  


The present study has been undertaken to evaluate physico-chemical parameters (pH, temperature, dissolved oxygen, free carbon dioxide, alkalinity and hardness) and zinc concentration in water bodies in and around Jaipur. Water samples from Jalmachal Lake, Nevta Lake, Amer Lake and Ramgarh Lake were analysed. Results reveal that the water of Jalmahal Lake is most polluted due to high pH, hardness, alkalinity, free carbon dioxide, zinc content, and a low level of dissolved oxygen. Contrarily Ramgarh Lake is least polluted, as it has high dissolved oxygen and low pH, alkalinity, free carbon dioxide, hardness and zinc content. PMID:12974460

Srivastava, Neera; Agrawal, Meena; Tyagi, Anupama



Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters  

NASA Technical Reports Server (NTRS)

Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude.

Witte, W. G.; Whitlock, C. H.; Usry, J. W.; Morris, W. D.; Gurganus, E. A.



Identification of key water quality characteristics affecting the filterability of biologically treated effluent in low-pressure membrane filtration.  


There are many water quality characteristics which could influence the filterability of biologically treated effluent from Melbourne's Western Treatment Plant (WTP). Statistical correlation was used to identify the key water characteristics affecting the microfiltration (MF) and ultrafiltration (UF) filterability in terms of permeate volume of the treated effluent. The models developed showed that turbidity, dissolved organic carbon (DOC) and total suspended solids (TSS) were the key factors which influenced the MF and UF filterability. Turbidity was the dominant factor affecting the accuracy of the model for MF filterability while DOC was the major factor affecting the accuracy of the model for UF filterability. A prediction accuracy of 85% was obtained for MF and 86% for UF filterability of the WTP effluent. The characteristics of the organic components of the wastewater were demonstrated by EEM spectra to have seasonal variation which would have reduced the prediction accuracy. As turbidity, DOC and TSS can be determined on-line, the models would be useful for rapid prediction of the filterability of WTP effluent and this may assist the control of low-pressure membrane filtration processes. PMID:20962408

Nguyen, T; Fan, L; Roddick, F A; Harris, J L



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

Code of Federal Regulations, 2013 CFR

...control, and stability on water. (a) For seaplanes and amphibians, during takeoff, taxiing, and landing, and in the conditions...and in the corresponding wind conditions, the seaplane or amphibian must be able to drift for five minutes with engines...



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

Code of Federal Regulations, 2012 CFR

...control, and stability on water. (a) For seaplanes and amphibians, during takeoff, taxiing, and landing, and in the conditions...and in the corresponding wind conditions, the seaplane or amphibian must be able to drift for five minutes with engines...