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1

Physiological characteristics of bacteria isolated from water brines within permafrost  

NASA Astrophysics Data System (ADS)

In the Arctic there are lenses of overcooled water brines (cryopegs) sandwiched within permafrost marine sediments 100 120 thousand years old. We have investigated the physiological properties of the pure cultures of anaerobic Clostridium sp. strain 14D1 and two strains of aerobic bacteria Psychrobacter sp. isolated from these cryopegs. The structural and physiological characteristics of new bacteria from water brines have shown their ability to survive and develop under harsh conditions, such as subzero temperatures and high salinity.

Shcherbakova, V.; Rivkina, E.; Laurinavichuis, K.; Pecheritsina, S.; Gilichinsky, D.

2004-01-01

2

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

PubMed

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

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

2011-08-01

3

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

PubMed

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

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

2014-01-01

4

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

PubMed Central

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

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

2014-01-01

5

Physiological Water Model Development.  

National Technical Information Service (NTIS)

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 r...

S. Doty

1993-01-01

6

Water characteristics  

SciTech Connect

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 estimated that acid rain was causing an estimated annual $5 billion loss in crop, forest, and aquatic yields. Several conferences were held during 1980 on acid rain problems. Groundwater contamination from acid rain was cited as one of the many current and anticipated problems in maintaining a clean and healthful water supply. Acid rain and vegetation interactions were studied in depth, as were the effects of acid precipitation on aquatic organisms. A procedure was developed which may be useful in the quantification of acid rain via isolated precipitation events. Acid precipitation was studied in forest environments. Two efforts assessed the potential for acid rain to leach into the soil. 154 references.

Smith, E.D.

1981-06-01

7

[Regulation effect of water storage in deeper soil layers on root physiological characteristics and leaf photosynthetic traits of cotton with drip irrigation under mulch].  

PubMed

A soil column culture experiment was conducted under the ecological and climatic conditions of Xinjiang to study the effects of water storage in deeper (> 60 cm) soil layers on the root physiological characteristics and leaf photosynthetic traits of cotton variety Xinluzao 13. Two treatments were installed, i.e., well-watered and no watering. The moisture content in plough layer was controlled at 70% +/- 5% and 55% +/- 5% of field capacity by drip irrigation under mulch during growth season. It was shown that the water storage in deeper soil layers enhanced the SOD activity and the vigor of cotton root, and increased the water use efficiency of plant as well as the leaf water potential, chlorophyll content, and net photosynthesis rate, which finally led to a higher yield of seed cotton and higher water use efficiency. Under well-watered condition and when the moisture content in plough layer was maintained at 55% of field capacity, the senescence of roots in middle and lower soil layers was slower, and the higher root vigor compensated the negative effects of impaired photosynthesis caused by water deficit to some extent. The yield of seed cotton was lower when the moisture content in plough layer was maintained at 55% of field capacity than at 70% of field capacity, but no significant difference was observed in the water use efficiency. Our results emphasized the importance of pre-sowing irrigation in winter or in spring to increase the water storage of deeper soil layers. In addition, proper cultivation practices and less frequent drip irrigation (longer intervals between successive rounds of irrigation) were also essential for conserving irrigation water and achieving higher yield. PMID:19795642

Luo, Hong-Hai; Zhang, Hong-Zhi; Du, Ming-Wei; Huang, Jian-Jun; Zhang, Ya-Li; Zhang, Wang-Feng

2009-06-01

8

[Water cultured propagation of Polygonum multiflorum and dynamic changes of physiological and biochemical characteristics during adventitious roots formation].  

PubMed

Water cultured propagation technology of Polygonum multiflorum was investigated with Rooting Powder No. 2 (ABT 2) comparison experiments, and the dynamic changes of endogenous hormones including indole acetic acid (IAA), abscisic acid (ABA), zeatin riboside (ZRs) contents and activities of indoleacetic acid oxidase (IAAO), polyphenol oxidase (PPO) were analyzed during rooting period. The results showed that rooting percentage of softwood cutting with 50 mg x L(-1) ABT2 and 10 mg x L(-1) ABT2 + 0.2% Urea + 0.2% KH2PO4 treatments was 94%, rooting percentage of softwood cuttings of control was 46% only. The adventitious rooting displayed three distinct phases i. e. root-inducing, root formation and root-elongating phases. The dynamic changes of contents of endogenous plant hormones (IAA, ABA, ZRs) and activities of IAAO, PPO tested were tightly related to the rooting process of soft-wood cuttings in P. multiflorum. During root-inducing phase the contents of IAA, ABA and ZRs decreased sharply, whereas ZRs content and IAAO activity kept higher level. IAA content reached the peak and PPO activity increased obviously during root formation phase, while IAAO activities and ABA, ZRs contents declined to minimum. During root-elongating phase PPO, IAAO activities were higher and IAA, ABA, ZRs contents kept steady. During rooting ABT2 (50 mg x L(-1)) treatment increased the content of IAA and PPO activity in cuttings, while the opposite result occurred in contents of ZRs, ABA and IAAO activity. PMID:21585047

Gao, Jie; Liu, Xiaohui; Yuan, Yike

2011-02-01

9

Physiological Aspects of Water Use Efficiency.  

National Technical Information Service (NTIS)

Grain sorghum plants growing in hydroponic cultures in a greenhouse were subjected to various levels of water stress by the addition of polyethylene glycol to the nutrient solutions. Several physiological parameters, including net photosynthesis, leaf dif...

C. Y. Sullivan J. D. Eastin J. M. Bennett N. V. Norcio

1978-01-01

10

Physiological characteristics of international female soccer players.  

PubMed

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

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

2014-02-01

11

Physiological characteristics of badminton match play.  

PubMed

The present study aimed at examining the physiological characteristics and metabolic demands of badminton single match play. Twelve internationally ranked badminton players (eight women and four men) performed an incremental treadmill test [VO(2peak = )50.3 +/- 4.1 ml min(-1) kg(-1) (women) and 61.8 +/- 5.9 ml min(-1) kg(-1) (men), respectively]. On a separate day, they played a simulated badminton match of two 15 min with simultaneous gas exchange (breath-by-breath) and heart rate measurements. Additionally, blood lactate concentrations were determined before, after 15 min and at the end of the match. Furthermore, the duration of rallies and rests in between, the score as well as the number of shots per rally were recorded. A total of 630 rallies was analysed. Mean rally and rest duration were 5.5 +/- 4.4 s and 11.4 +/- 6.0 s, respectively, with an average 5.1 +/- 3.9 shots played per rally. Mean oxygen uptake (VO(2)), heart rate (HR), and blood lactate concentrations during badminton matches were 39.6 +/- 5.7 ml min(-1) kg(-1) (73.3% VO(2peak)), 169 +/- 9 min(-1) (89.0% HR(peak)) and 1.9 +/- 0.7 mmol l(-1), respectively. For a single subject 95% confidence intervals for VO(2) and HR during match play were on average 45.7-100.9% VO(2peak) and 78.3-99.8% HR(peak). High average intensity of badminton match play and considerable variability of several physiological variables demonstrate the importance of anaerobic alactacid and aerobic energy production in competitive badminton. A well-developed aerobic endurance capacity seems necessary for fast recovery between rallies or intensive training workouts. PMID:17473928

Faude, Oliver; Meyer, Tim; Rosenberger, Friederike; Fries, Markus; Huber, Günther; Kindermann, Wilfried

2007-07-01

12

FISH PHYSIOLOGY, TOXICOLOGY, AND WATER QUALITY:  

EPA Science Inventory

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

13

Physiological and clinical characteristics of andropause.  

PubMed

The process of aging in man involves a lot of functional and structural changes in the body organs and systems. In this review we shall characterize the physiological and clinical manifestations of andropause. We'll review the physiological basis of the ageing process, the age-related changes in the testosterone secretion regulation, and the dynamics of androgen action and active testosterone metabolism. We also investigate the multifactorial etiology of age-related physiological changes--the body undergoes changes in its structure, there is a loss of muscle strength and decline in physical functions. Sexual dysfunction, hypogonadism and psychological changes are also commonly observed symptoms in this condition. Changes of similar kind can also be seen in young males with androgen deficiency. The age-related changes in physiological functions can potentially lead to some important consequences such as reduced physical activity, higher risk of developing specific diseases (ischemic heart disease, diabetes, osteoporosis), diminished capacity to recover after acute diseases, but most often it leads to increased fracture predisposition. All these may eventually affect negatively the self-care capacity of patients making them require a long-term professional care, and lead to severe psychological and social isolation and increased mortality and change in quality of life. To limit the age-related physiological decline in serum testosterone levels, we should be able to tackle the still unresolved important clinical issue--can hormone replacement therapy administered to elderly men improve their functional status, prevent diseases from developing, improve quality of life and reduce fracture risk. The data included in the present review will contribute to determining the potential benefits and risks of testosterone replacement therapy. PMID:19437894

Delev, Delian P; Kostadinova, Ivanka I; Kostadinov, Ilia D; Ubenova, Dafinka K

2009-01-01

14

Aquaporin water channels in gastrointestinal physiology  

PubMed Central

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

Ma, Tonghui; Verkman, A S

1999-01-01

15

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.

Weitzman, Richard E.; Kleeman, Charles R.

1979-01-01

16

Physiological characteristics of top level off-road motorcyclists  

PubMed Central

Objectives: The study aims to analyse the physiological characteristics of top level off-road motocross, enduro, and desert rally motorcyclists to facilitate the design of a specific training program. Results: The physical demands of the various races appear to influence the development of distinct musculoskeletal characteristics, as well as aerobic and anaerobic metabolism. Motocross riders have more muscle mass, higher isokinetic handgrip strength, and greater aerobic power than enduro and desert rally riders. However, there are no significant anthropometric and physiological differences between desert rally and enduro riders. Desert rally riders tend to be overweight with maximum aerobic power similar to that of healthy individuals. The mechanical characteristics of the motorcycle and the technical and tactical skills of the riders seem to be more important for race success than the metabolic capabilities of the rider. Conclusions: Desert rally and enduro riders present similar anthropometric and physiological characteristics. Both have a maximum aerobic power similar to that of healthy normal individuals, although desert rally riders tend to be overweight. Motocross riders on the other hand, have more muscle mass, more strength, and greater aerobic power. The differences observed suggest the need for a specific training program to address the requirements of different riders to reduce the possibility of injury.

Gobbi, A; Francisco, R; Tuy, B; Kvitne, R; Nakamura, N

2005-01-01

17

Physiological demands of water polo goalkeeping.  

PubMed

The purpose of this study was to investigate the physiological demands of water polo goalkeepers during competition and to examine whether the playing intensity of the goalkeeper decreases as the game time progresses. During eight official games the following measurements were performed on eight elite water polo goalkeepers: (1) video analysis of activities, (2) monitoring of blood lactate (BLa) and (3) continuous recording of heart rate (HR) responses. Mean HR of total mixed playing time, excluding breaks among quarters, was 134.3+/-20.3bpm for 36 (4x9) min of game duration. The large portion of the game (85.6%) was performed with a HR lower than 151.4+/-2.7bpm (82.1+/-1.4% of HRpeak) an intensity corresponding to the players' anaerobic threshold (3.49+/-0.60mmolL(-1)). However, an important part of the game (14.4%) contained activities with sudden HR increases above the anaerobic threshold. Mean BLa accumulation at the end of each game period was 3.93+/-1.64mmolL(-1). Individual lactate values varied from 2.0 to 8.3mmolL(-1). Goalkeeper exercise intensity reached its peak value (152.5+/-10.1bpm) whenever his team competed with one player less due to player exclusion. No significant differences were found in HR, BLa and the percentage of time spent in each of the activity categories between game periods. In conclusion, goalkeeper's game can be described as of intermittent nature with great variability in the intensity performed. The greater part of the game is associated with a low aerobic demand while an important part of the game contains activities with sudden HR increases above the anaerobic threshold implying also a considerable demand on anaerobic metabolism. The intensity of exercise of the goalkeeper does not differ from period to period. PMID:18077216

Platanou, T

2009-01-01

18

Physiological Memory in Primary Auditory Cortex: Characteristics and Mechanisms  

Microsoft Academic Search

''Physiological memory'' is enduring neuronal change sufficiently specific to represent learned information. It transcends both sensory traces that are detailed but transient and long-term physiological plasticities that are insufficiently specific to actually repre- sent cardinal details of an experience. The specificity of most physiological plasticities has not been comprehensively studied. We adopted receptive field analysis from sensory physiology to seek

Norman M. Weinberger

2001-01-01

19

Comparative physiology of salt and water stress.  

PubMed

Plant responses to salt and water stress have much in common. Salinity reduces the ability of plants to take up water, and this quickly causes reductions in growth rate, along with a suite of metabolic changes identical to those caused by water stress. The initial reduction in shoot growth is probably due to hormonal signals generated by the roots. There may be salt-specific effects that later have an impact on growth; if excessive amounts of salt enter the plant, salt will eventually rise to toxic levels in the older transpiring leaves, causing premature senescence, and reduce the photosynthetic leaf area of the plant to a level that cannot sustain growth. These effects take time to develop. Salt-tolerant plants differ from salt-sensitive ones in having a low rate of Na+ and Cl-- transport to leaves, and the ability to compartmentalize these ions in vacuoles to prevent their build-up in cytoplasm or cell walls and thus avoid salt toxicity. In order to understand the processes that give rise to tolerance of salt, as distinct from tolerance of osmotic stress, and to identify genes that control the transport of salt across membranes, it is important to avoid treatments that induce cell plasmolysis, and to design experiments that distinguish between tolerance of salt and tolerance of water stress. PMID:11841667

Munns, R.

2002-02-01

20

The Clinical Physiology of Water Metabolism  

PubMed Central

Hyperosmolality occurs when there are defects in the two major homeostatic mechanisms required for water balance—thirst and arginine vasopressin (AVP) release. In this situation hypotonic fluids are lost in substantial quantities causing depletion of both intracellular and extracellular fluid compartments. Patients with essential hypernatremia have defective osmotically stimulated AVP release and thirst but may have intact mechanisms for AVP release following hypovolemia. Hyperosmolality can also be seen in circumstances in which impermeable solutes are present in excessive quantities in extracellular fluid. Under these conditions there is cellular dehydration and the serum sodium may actually be reduced by water drawn out of cells along an osmotic gradient. Hyposmolality and hyponatremia may be seen in a variety of clinical conditions. Salt depletion, states in which edema occurs and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) may all produce severe dilution of body fluids resulting in serious neurologic disturbances. The differential diagnosis of these states is greatly facilitated by careful clinical assessment of extracellular fluid volume and by determination of urine sodium concentration. Treatment of the hyposmolar syndromes is contingent on the pathophysiology of the underlying disorder; hyponatremia due to salt depletion is treated with infusions of isotonic saline whereas mild hyponatremia in cirrhosis and ascites is best treated with water restriction. Severe symptomatic hyponatremia due to SIADH is treated with hypertonic saline therapy, sometimes in association with intravenous administration of furosemide. Less severe, chronic cases may be treated with dichlormethyltetracycline which blocks the action of AVP on the collecting duct. ImagesFigure 43.Figure 44.Figure 47.

Weitzman, Richard E.; Kleeman, Charles R.

1980-01-01

21

[Physiological characteristics of rice seedlings roots under aluminum stress].  

PubMed

A hydroponic experiment was conducted with the four-leaf stage seedlings of aluminum (Al)-susceptible rice variety IR24 and Al-tolerant rice varieties Jingyou 725 and Liangyoupeijiu to study the physiological characteristics of the seedlings roots under effects of 0, 0.5 mmol x L(-1), and 7.5 mmol x L(-1) of Al. Under the stress of 7.5 mmol Al x L(-1), Al-tolerant varieties had a far lesser decrement of root vigor than Al-susceptible variety, while the Al-susceptible variety had a higher root mitochondria H2O2 content than Al-tolerant varieties. Al stress induced a lesser increment of CAT activity in the root mitochondria of all tested varieties. With the increasing Al concentration, the root mitochondria POD activity of IR24 and Jingyou 725 decreased after an initial increase while that of Liangyoupeijiu was increasing, and the root mitochondria APX activity of IR24 decreased after an initial increase while that of Jingyou 725 and Liangyoupeijiu was increasing. The root glutamic acid content of all tested varieties showed an increase-decline trend, and their citric acid content decreased while PEP content increased. The ratio of cyanide-resistant respiration rate to total respiration rate of Al-tolerant Jingyou 725 and Liangyoupeijiu increased obviously, compared with that of Al-susceptible IR24. PMID:19899473

Xie, Guo-Sheng; Shi, Rui-Hong; Pang, Zhen-Wu; Cai, Ke-Tong

2009-07-01

22

Differential physiological and molecular response of barley genotypes to water deficit.  

PubMed

Changes in physiological parameters (relative water content (RWC), biomass, water use efficiency (WUE), net photosynthetic yield (PN) and quantum yield of PSII (Fv/Fm)), in proline and sugar content, and expression profile of genes reported to be associated with the barley response to water deficit, including LEA genes, NHX1, Hsdr4, BLT101 and genes encoding transcription factors (HvDREB1, HvABF1, HvABI5 and HvZIP1), were analyzed in seedlings of nine barley genotypes subjected to a progressive increase in water deficit. Seedlings of all genotypes wilted when the soil water content (SWC) declined from 65% (control conditions) to 10% (severe drought conditions), but recovered turgor within a few hours of re-watering. However, when severe drought conditions were prolonged for a week, large differences in survival characteristics were observed between genotypes after re-watering. Multivariate analysis of the changes in physiological and molecular characteristics allowed several different homogenous groups within the genotypes to be distinguished, depending on stress intensity. Furthermore, integration between the stress-response traits was found and was shown to vary depending on the genotype and the stress level. Based on analysis of physiological traits and survival characteristics, two barley genotypes with high adaptability to the stress conditions (cv. Saida and breeding line Cam/B1), and two with low adaptability (cv. Express and breeding line Harmal), were identified. In addition, only changes in expression of the genes HvZIP1, encoding a b-ZIP-type transcription factor, and Hsdr4, encoding a protein of unknown function, were shown to be linked with adaptability of barley to water deficit. In summary, physiological and molecular data revealed large, stress-level-dependent differences between the barley cultivars and breeding lines tested in their response to water deficit. PMID:24811679

de Mezer, Mateusz; Turska-Taraska, Anna; Kaczmarek, Zygmunt; Glowacka, Katarzyna; Swarcewicz, Barbara; Rorat, Tadeusz

2014-07-01

23

Tai chi: physiological characteristics and beneficial effects on health  

PubMed Central

Objectives—To assess the characteristic effects of Tai Chi Chuan (TCC) exercise on metabolism and cardiorespiratory response, and to measure its effect on cardiorespiratory function, mental control, immune capacity, and the prevention of falls in elderly people. Design—A review of controlled experimental studies and clinical trials designed with one of two aims: either to assess physiological responses during the performance of TCC or to assess the impact of this exercise on general health and fitness. Main outcome measures—Metabolic rate, heart rate, blood pressure, ventilation, maximal oxygen uptake (O2MAX), immune capacity, falls, and fall related factors. Subjects—A total of 2216 men and women. Results—Under review were 31 original studies, published in Chinese or English journals, that met the criteria for inclusion. Most of the papers written in Chinese had not been introduced into the Western literature. Nine of these studies showed that TCC can be classified as moderate exercise, as its does not demand more than 55% of maximal oxygen intake. When this form of exercise and others conducted at equal intensity were compared, TCC showed a significantly lower ventilatory equivalent (E/O2MAX). Evidence provided by cross sectional and longitudinal studies suggests that TCC exercise has beneficial effects on cardiorespiratory and musculoskeletal function, posture control capacity, and the reduction of falls experienced by the elderly. Conclusions—TCC is a moderate intensity exercise that is beneficial to cardiorespiratory function, immune capacity, mental control, flexibility, and balance control; it improves muscle strength and reduces the risk of falls in the elderly. Key Words: Tai Chi Chuan; elderly; falls; cardiovascular; ventilation

Li, J; Hong, Y; Chan, K

2001-01-01

24

Physiological characteristics of elite and sub-elite badminton players.  

PubMed

The aims of this study were to establish the physical and physiological attributes of elite and sub-elite Malaysian male badminton players and to determine whether these attributes discriminate elite players from sub-elite players. Measurements and tests of basic anthropometry, explosive power, anaerobic recovery capacity, badminton-specific movement agility, maximum strength, and aerobic capacity were conducted on two occasions, separated by at least one day. The elite (n = 12) and sub-elite (n = 12) players' characteristics were, respectively: mean age 24.6 years (s = 3.7) and 20.5 years (s = 0.7); mass 73.2 kg (s = 7.6) and 62.7 kg (s = 4.2); stature 1.76 m (s = 0.07) and 1.71 m (s = 0.05); body fat 12.5% (s = 4.8) and 9.5% (s = 3.4); estimated VO(2max) 56.9 ml . kg(-1) . min(-1) (s = 3.7) and 59.5 ml . kg(-1) . min(-1) (s = 5.2). The elite players had greater maximum absolute strength in one-repetition maximum bench press (P = 0.015) compared with the sub-elite players. There were significant differences in instantaneous lower body power estimated from vertical jump height between the elite and sub-elite groups (P < 0.01). However, there was no significant difference between groups in shuttle run tests and on-court badminton-specific movement agility tests. Our results show that elite Malaysian male badminton players are taller, heavier, and stronger than their sub-elite counterparts. The test battery, however, did not allow us to discriminate between the elite and sub-elite players, suggesting that at the elite level tactical knowledge, technical skills, and psychological readiness could be of greater importance. PMID:19967588

Ooi, Cheong Hwa; Tan, Albert; Ahmad, Azwari; Kwong, Kien Weng; Sompong, Ruji; Ghazali, Khairul Aswadi Mohd; Liew, Swee Lee; Chai, Wen Jin; Thompson, Martin William

2009-12-01

25

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

EPA Science Inventory

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

26

Water as an essential nutrient: the physiological basis of hydration.  

PubMed

How much water we really need depends on water functions and the mechanisms of daily water balance regulation. The aim of this review is to describe the physiology of water balance and consequently to highlight the new recommendations with regard to water requirements. Water has numerous roles in the human body. It acts as a building material; as a solvent, reaction medium and reactant; as a carrier for nutrients and waste products; in thermoregulation; and as a lubricant and shock absorber. The regulation of water balance is very precise, as a loss of 1% of body water is usually compensated within 24 h. Both water intake and water losses are controlled to reach water balance. Minute changes in plasma osmolarity are the main factors that trigger these homeostatic mechanisms. Healthy adults regulate water balance with precision, but young infants and elderly people are at greater risk of dehydration. Dehydration can affect consciousness and can induce speech incoherence, extremity weakness, hypotonia of ocular globes, orthostatic hypotension and tachycardia. Human water requirements are not based on a minimal intake because it might lead to a water deficit due to numerous factors that modify water needs (climate, physical activity, diet and so on). Water needs are based on experimentally derived intake levels that are expected to meet the nutritional adequacy of a healthy population. The regulation of water balance is essential for the maintenance of health and life. On an average, a sedentary adult should drink 1.5 l of water per day, as water is the only liquid nutrient that is really essential for body hydration. PMID:19724292

Jéquier, E; Constant, F

2010-02-01

27

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.

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

2007-01-01

28

Physiology  

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

2008-01-01

29

Physiological characteristics of the seagrass Posidonia sinuosa along a depth-related gradient of light availability  

Microsoft Academic Search

Physiological plasticity has the capacity to prolong seagrass survival under reduced light conditions. However, when light is attenuated across a depth gradient, the relative importance of this over other mechanisms for tolerating long-term light reduction (such as morphological adjustments and shoot loss) has been questioned. This study aimed to describe a number of the physiological characteristics of Posidonia sinuosa Cambridge

Catherine Collier; Paul Lavery; Peter Ralph; Ray Masini

2008-01-01

30

Relationship between anthropometric and physiological characteristics in youth soccer players.  

PubMed

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

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

2009-07-01

31

Physiological characteristics and performance of top U.S. biathletes.  

PubMed

Success in biathlon involves skiing fast and shooting accurately. The purpose of this study was to determine whether physiological laboratory test results relate to success in biathlon. Tests included treadmill run and double-pole lactate profile and VO2peak tests, and a double-pole peak power test (UBP). 1993 National Points Rank (NR), racing ski time (ST), and shooting percentage (SP) from 1993 World Team Trials and laboratory test results (1993; N = 11 males, 10 females) were examined. Of athletes tested, six males and six females were top 10 U.S. ranked. Significance was identified between NR and ST (males, r = -0.88; females, r = -0.91). NR and SP were related for females (r = 0.75). Maximum run time during the VO2peak test was the only parameter related to NR (r = 0.72) or ST (r = -0.80) for males. Significance was identified for an uphill 1 km on snow double-pole time trial to NR (r = -0.84) and SP (r = -0.79) (subgroup; N = 8 males). For females, NR was related to running VO2peak (r = 0.81) and UBP (r = 0.95). Double-pole and running VO2peak were related to SP for women. This study suggests that SP is more important to NR for females than for males, and gender-specific tests might better predict success in elite biathlon skiers. PMID:8531629

Rundell, K W; Bacharach, D W

1995-09-01

32

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

PubMed

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

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

2013-01-01

33

Thermodynamic efficiency and physiological characteristics of the chick anterior latissimus dorsi muscle  

Microsoft Academic Search

1.The physiological characteristics of the chick anterior latissimus dorsi muscle were measured and compared with those of the adjacent posterior latissimus dorsi muscle. The rate of shortening of the anterior latissimus dorsi was about 15 times slower than that of the posterior muscle.2.The anterior latissimus dorsi was found to be able to sustain isometric tension for long periods of time.

G. Goldspink; R. E. Larson; R. E. Davies

1970-01-01

34

Physiological characteristics of the best Eritrean runners-exceptional running economy  

Microsoft Academic Search

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

Alejandro Lucia; Jonathan Esteve-Lanao; Jesús Oliván; Félix Gómez-Gallego; Catalina Santiago; Margarita Pérez; Carolina Chamorro-Viña; Carl Foster

2006-01-01

35

RELATIONSHIP BETWEEN BLOOD PHYSIOLOGICAL ATTRIBUTES AND CARCASS CHARACTERISTICS IN IRANIAN FAT-TAILED SHEEP  

Microsoft Academic Search

The relationship between blood physiological attributes and carcass characteristics was studied in 40 randomly selected 8-month-old ram lambs of Ghezel and Mehraban (20 rams per breed) sheep. One day before slaughter, blood samples were obtained after a 24 hr fast. Serum samples were assayed for glucose, cholesterol, serum urea nitrogen (SUN), total protein, albumin, triglycerides, creatinine, and calcium and magnesium

M. J. ZAMIRI; A. REZAEI-ROODBARI

36

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.

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

2012-01-01

37

Thermal characteristics of running waters  

Microsoft Academic Search

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

J. V. Ward

1985-01-01

38

Performance and Physiological Responses of Dairy Cattle to Water Total Dissolved Solids (TDS) Under Heat Stress  

Microsoft Academic Search

Shapasand, M., Alizadeh, A.R., Yousefi, M. and Amini, J. 2010. Performance and physiological responses of dairy cattle to water total dissolved solids (TDS) under heat stress. J. Appl. Anim. Res., 38: 165–168.To determine the effects of water total dissolved solids containing 3400 ppm (HTDS) or 900 ppm (LTDS) on feed intake, water consumption, milk production and physiological response of heat

M. Shapasand; A. R. Alizadeh; M. Yousefi; J. Amini

2010-01-01

39

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

40

Physical characteristics, physiological attributes, and on-field performances of soccer goalkeepers.  

PubMed

The soccer goalkeeper (GK) is required to perform strenuous actions during practice sessions and actual games. One of the objectives of those professionals who work with GKs is to obtain relevant information on physical characteristics and physiological attributes of GKs, and to use it effectively when planning training programs for them. This article has three purposes: (a) to review a series of studies (n = 23) on physical characteristics, physiological attributes, and on-field performances of soccer GKs; (b) to outline a number of methodological limitations and research concerns associated with these studies; and (c) to suggest several practical recommendations for soccer coaches who work with GKs. Four main findings emerged from our review: (a) professional adult GKs usually are over 180 cm tall and have a body mass of over 77 kg; (b) studies on agility and speed produced mixed results, with some showing similar values between GKs and field players and others showing reduced performance in GKs; (c) GKs usually have higher vertical jump values when compared with players playing the various field positions; (d) GKs cover approximately 5.5 km during a game, mostly by walking and jogging. Four methodological limitations and research concerns associated with the reviewed studies were discussed, among them the lack of a longitudinal approach and the lack of on-field performance studies. Three practical recommendations are made for coaches, one of which is that coaches should adopt a careful approach when selecting testing protocols and devices for the assessment of GKs' physiological attributes. PMID:22248551

Ziv, Gal; Lidor, Ronnie

2011-12-01

41

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

PubMed Central

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

Mundan, Victor; Muiva, Margaret; Kimani, Samuel

2013-01-01

42

Physiological traits used in the breeding of new cultivars for water-scarce environments  

Microsoft Academic Search

A physiological understanding of plants’ responses to drought has often been sought on the pretext that this understanding will assist plant breeders develop higher yielding varieties for water-scarce environments. However, despite an extensive literature on plants’ response to drought there are few documented examples where a physiological understanding of drought has identified traits that limit yield under drought and where

Richard A. Richards

2006-01-01

43

Abyssal Characteristics of the World Ocean Waters.  

National Technical Information Service (NTIS)

The abyssal characteristics of the World Ocean, including not only temperature but salinity, density, oxygen, and silica, are displayed on both maps and vertical sections to examine the origins of waters of some of the major basins. Although the coldest w...

A. W. Mantyla J. L. Reid

1983-01-01

44

[Physiological and biochemical characteristics of recalcitrant seed under the condition of true dormancy: a review].  

PubMed

The review considers and sums up the results of studies of physiological and biochemical characteristics of dormant and germinating recalcitrant seed (the object of the study, the seed of common horse chestnut, Aesculus hippocastanum L., is viewed as an exemplary case). The results of analysis of the proteomes of the axis and cotyledons have been studied and the effects of the stratification, assessed. Gene expression has been studied at the level of protein synthesis; the protein-synthesizing capacity of the cells of the embryonic axis and cotyledon storage parenchyma of mature seed and seed undergoing stratification. The extent to which the functionally active translation machinery of ripe seed depends on transcription has been assessed, and the ability to synthesize protein under the conditions of stratification has been established. It is concluded that the embryonic axis of dormant seed lacks innate dormancy and that the isolated axis exhibits diverse sensitivity to exogenous abscisic acid and other physiologically active compounds. PMID:17619586

Gumilevskaia, N A; Azarkovich, M I

2007-01-01

45

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

EPA Science Inventory

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

46

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)

1999-12-01

47

Physiological Effects of Water Stress on Young Corn Plants.  

National Technical Information Service (NTIS)

Laboratory experiments were used to investigate the mechanism of plant response to water stress by determining the sensitivity of leaf elongation, photosynthesis and transpiration in young corn plants to a decrease in leaf water potential. The sensitivity...

E. W. R. Barlow

1974-01-01

48

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

PubMed Central

Eleven Acanthamoeba isolates, obtained from Acanthamoeba keratitis patients, from contact lens cases of non-Acanthamoeba keratitis patients, from asymptomatic individuals, from necrotic tissue, and from tap water and two reference strains were investigated by morphological, molecular biological, and physiological means in order to discriminate clinically relevant and nonrelevant isolates. All clinically relevant isolates showed Acanthamoeba sp. group II morphology. 18S ribosomal DNA sequencing revealed sequence type T4 to be the most prevalent group among the isolates and also the group recruiting most of the pathogenic strains. Interestingly, within T4 the strains of no clinical relevance clustered together. Moreover, physiological properties appeared to be highly consistent with initial pathogenicity and with sequence clustering. Altogether, the results of our study indicate a correlation between the phylogenetic relationship and pathogenicity.

Walochnik, Julia; Obwaller, Andreas; Aspock, Horst

2000-01-01

49

Genetic and physiological controls of growth under water deficit.  

PubMed

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

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

2014-04-01

50

Dosimetry of [0-15] water: A physiologic approach  

Microsoft Academic Search

[O-15] water is a popular now based radiotracer (half life 2.03 m) used in measuring rCBF by PET. Previous dosimetry estimates assumed that [O-15] water instantaneously reached equilibrium with total body water. However, the biodistribution of this short-lived radiopharmaceutical is dependent upon blood flow to various organs. This assumption of instantaneous equilibrium leads to an underestimation of radiation dose to

S. Narayana; L. L. Boles; J. A. Ponto

1994-01-01

51

Physiological Effects of Iodinated Water on Thyroid Function  

Microsoft Academic Search

SUMMARY Iodine has been used as a potable water treatment and storage bactericidal agent by NASA for over three decades beginning with the Apollo program, and was a critical factor for the achievement of human space flight. Iodine is currently used for Space Shuttle potable water microbial control and is planned for the U.S. com- ponent of the International Space

Kathleen A. McMonigal; Richard L. Sauer; Scott M. Smith; Terrence J. Pattinson; Patricia L. Gillman; Lizanne N. Pierre; Daniel L. Feeback

52

Physiological and biochemical responses of peanut genotypes to water deficit  

Microsoft Academic Search

The effects of drought on water relations, gas exchanges, solutes accumulation, and catalase (CAT), ascorbato peroxidase (APX), and guaiacol peroxidase (GPX) activities were studied in five Arachis genotypes, grown under control or withholding water conditions. Drought stress reduced plant growth of all genotypes; the genotypes A. duranensis 7988 and A. stenosperma SV2411 being characterized as the most drought-sensitive and A.

André D. Azevedo Neto; Rejane J. M. C. Nogueira; Péricles A. Melo Filho; Roseane C. Santos

2010-01-01

53

Cold Water Fatalities: An Overview of Physiological Responses.  

ERIC Educational Resources Information Center

Cold water fatalities are described and defined, including drownings, trauma, hydrocution and hypothermia. The levels of hypothermia are outlined, and symptoms and steps to stop and reverse hypothermia are described. (DS)

Bernhartsen, J. C.; Schlenker, Richard

1981-01-01

54

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

NASA Astrophysics Data System (ADS)

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

Roberts, John

2000-10-01

55

Physiological response of potato plants to soil salinity and water deficit  

Microsoft Academic Search

The physiological response of potatoes as affected by salinity or water deficit was investigated. Leaf water and osmotic potentials declined significantly as stress conditions intensified. However, a positive turgor was maintained throughout the entire growth period. This resulted from the fact that plants adjusted osmotically. Under salinity, it was mainly achieved by the accumulation of chloride and proline, while under

Bruria Heuer; Arie Nadler

1998-01-01

56

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.

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

2014-01-01

57

Physiology of Acidophilic Bacteria of Acid Mine Water.  

National Technical Information Service (NTIS)

Two new acidophilic bacteria (strains M-1 and M-2) were isolated from coal mine waters, characterized, and placed in the genus Pseudomonas, as Pseudomonas acidophila, sp. n. Obligate acidophiles unable to grow at neutrality, they are capable of rapid and ...

H. L. Manning T. M. Cook

1972-01-01

58

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

PubMed

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

2013-09-01

59

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

PubMed

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

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

2013-05-01

60

Characteristics of physiological inducers of the ethanol utilization (alc) pathway in Aspergillus nidulans.  

PubMed Central

The ethanol utilization (alc) pathway in Aspergillus nidulans is one of the strongest expressed gene systems in filamentous fungi. The pathway-specific activator AlcR requires the presence of an inducing compound to activate transcription of genes under its control. We have demonstrated recently that acetaldehyde is the sole physiological inducer of ethanol catabolism. In the present study we show that compounds with catabolism related to that of ethanol, i.e. primary alcohols, primary monoamines and l-threonine, act as inducers because their breakdown results in the production of inducing aliphatic aldehydes. Such aldehydes were shown to induce the alc genes efficiently at low external concentrations. When ethanol is mixed with representatives of another class of strong direct inducers, ketones, the physiological inducer, acetaldehyde, prevails as effector. Although direct inducers essentially carry a carbonyl function, not all aldehydes and ketones act as inducers. Structural features discriminating non-inducing from inducing compounds concern: (i) the length of the aliphatic side group(s); (ii) the presence and nature of any non-aliphatic substituent. These characteristics enable us to predict whether or not a given carbonyl compound will induce the alc genes.

Flipphi, Michel; Kocialkowska, Janina; Felenbok, Beatrice

2002-01-01

61

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.

Hyun, Se-Hee

2014-01-01

62

Physiological responses to water stress following a conditioning period in berseem clover  

Microsoft Academic Search

Berseem clover (Trifolium alexandrinum L.) is an important crop in semi-arid regions; its herbage and seed yields are often reduced by water stress. Our objectives\\u000a were (i) to determine the effect of water stress, applied after a conditioning period, on water relations, proline accumulation\\u000a and plant dry weight, and (ii) to investigate if some physiological responses differed in varieties of

A. Iannucci; A. Rascio; M. Russo; N. Di Fonzo; P. Martiniello

2000-01-01

63

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.

SASAKI, Satohiko

2008-01-01

64

Physiological and functional characteristics of Propionibacterium strains of the poultry microbiota and relevance for the development of probiotic products.  

PubMed

The prevention and control of pathogens colonization through probiotics administration in poultry feeding is of increasing interest. The genus Propionibacterium is an attractive candidate for the development of probiotic cultures as they produce short chain fatty acids (SCFA) by carbohydrates fermentation. The presence of strains of this genus in hens of conventional production systems and backyard hens was investigated. Propionibacteria were isolated from the intestine and identified by physiological and biochemical tests. PCR amplification of the 16S rRNA gene of the isolates was performed and products were compared with sequences from databases. The presence of the genus Propionibacterium was demonstrated in 26% of hens and Propionibacterium acidipropionici and Propionibacterium avidum were the identified species. A comparative study of their physiological and functional characteristics was performed. P. acidipropionici strains were the most resistant to in vitro gastrointestinal digestion, but the adhesion to intestinal tissue was strain dependent. Some differences were found between both species with respect to their growth and SCFA production in an in vitro cecal water model, but all the strains were metabolically active. The production of SCFA in cecal slurries inoculated with the strain P. acidipropionici LET 105 was 30% higher than in non-inoculated samples. SCFA concentrations obtained were high enough to inhibit Salmonella enterica serovar Enteritidis when assayed in a cecal water model. P. acidipropionici LET 105 was also able to compete with Salmonella for adhesion sites on the intestinal mucosa in ex vivo assays. Results contribute to the knowledge of the species diversity of the genus Propionibacterium in the intestine of poultry and provide evidence of their potential for probiotics products development. PMID:23973927

Argañaraz-Martínez, Eloy; Babot, Jaime D; Apella, María C; Perez Chaia, Adriana

2013-10-01

65

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

PubMed

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

2013-11-01

66

Biochemical and physiological characteristics of semen of sex-reversed female rainbow trout (Oncorhynchus mykiss, Walbaum).  

PubMed

This works studies the biochemical (protein concentration, osmolality, antitrypsin activity, lactate dehydrogenase activity) and physiological characteristics (sperm motility characteristics) of semen of sex-reversed female rainbow trout (n=42) obtained with the application of 11?-hydroksyandrostendione for sex reversal. All data were arbitrarily divided into three classes depending on the percentage of sperm motility: I XX<25%; II XX 25-50% and III XX>50%. The average percentage of sperm motility was 18±7% n=12 (group I XX); 42±6% n=15 (group II XX) and 65±12% n=15 for group III XX, respectively) to link the values of semen parameters to the maturation stage of semen. Semen from 12 normal males of the same age was used as a reference group. Sperm concentration as well as protein concentration, osmolality, antitrypsin activity, and lactate dehydrogenase activity in seminal plasma of sex-reversed females were higher compared with the values obtained for normal male rainbow trout. The values of these parameters declined with the increasing percentage of sperm motility toward values established for normal males. The fertilization success of semen (3×10(6) spermatozoa/egg) of sex-reversed females was very high (above 90%) for both the percentage of eyed embryos and hatched larvae and was related to sperm motility classes. Correlations between the quality parameters of sex-reversed females semen corresponded to those established previously for the semen of normal male rainbow trout. Antitrypsin activity, lactate dehydrogenase, protein concentration, and osmolality were found to be characteristic of seminal plasma of sex-reversed females. The maturity of sex-reversed female spermatozoa seems to be associated with the decline in the values of those parameters toward the values characteristic for seminal plasma of normal males. PMID:21924466

Nynca, Joanna; Ku?mi?ski, Henryk; Dietrich, Grzegorz J; Hliwa, Piotr; Dobosz, Stefan; Liszewska, Ewa; Karol, Halina; Ciereszko, Andrzej

2012-01-01

67

Metabolic and Physiological Characteristics of Novel Cultivars from Serpentinite Seep Fluids  

NASA Astrophysics Data System (ADS)

Subsurface waters associated with the alteration of ultramafic rocks become highly reducing and alkaline through a process known as serpentinization. As habitat, these fluids are in many ways metabolically constraining but can provide sufficient energy for chemolithotrophy. As part of an ongoing effort to characterize these communities, heterotrophic enrichment cultures and anaerobic microcosms were initiated with alkaline waters found at three geographically and geochemically distinct sites of active serpentinization. These include the Northern Apennine ophiolite in the Ligurian region of Italy, the Tablelands ophiolite at Gros Morne National Park, Canada and the Coast Range ophiolite at McLaughlin Natural Reserve, California. Enrichment cultures at pH 11 yielded numerous isolates related to Proteobacteria and Firmicutes, some of which are closely related to other cultivars from high pH and subsurface environments. Anaerobic water samples were amended with combinations of electron donors (hydrogen, complex organics, acetate) and acceptors (ferric iron, sulfate) in a block design. After several weeks of incubation, DNA was extracted from cell concentrations and community differences were compared by TRFLP. Of particular interest is the isolation of a putative iron reducing Firmicute from samples enriched with complex organic compounds and ferric citrate. Ongoing studies are aimed at characterizing the physiology of these isolates. These data provide important insights into the metabolic potential of serpentinite subsurface ecosystems, and are a complement to culture-independent genomic analyses.

Nelson, B.; Chowdhury, S.; Brazelton, W. J.; Schrenk, M. O.

2011-12-01

68

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

69

Physiological parameters of desert truffle mycorrhizal Helianthemun almeriense plants cultivated in orchards under water deficit conditions  

Microsoft Academic Search

Physiological parameters of mycorrhizal symbiosis by Helianthemum almeriense and Terfezia claveryi in orchards were characterized under water deficit conditions. Our orchard included 40 mycorrhizal and 40 nonmycorrhizal plants. Only mycorrhizal plants survived at the beginning of the experimental period, indicating dependency on fungal symbionts in roots for survival. Drought stress significantly affected the mycorrhizal colonization percentage which was 70% in

Asunción Morte; Alfonso Navarro-Ródenas; Emilio Nicolás

2010-01-01

70

Physiological characteristics of wild Atlantic salmon post-smolts during estuarine and coastal migration  

USGS Publications Warehouse

Changes were measured in some of the major physiological variables associated with seawater adaptability, growth and energetics in wild Atlantic salmon Salmo salar smolts and post-smolts migrating from the river and through the estuary, fjord and coastal areas in the River Orkla and the Trondheimsfjord, Norway during late May to early June. Gill Na+,K+-ATPase activity increased to levels of 12-16 ??mol ADP mg protein-1 h -1 in post-smolts caught in higher salinity zones, probably representing long-term levels of Atlantic salmon post-smolts in oceanic conditions. Muscle moisture was regulated within narrow limits (77.7-78.7%) in fish from all zones during both years, suggesting that post-smolts adapt to marine conditions without any long-term disturbance of hydro-mineral balance. Lipid and glycogen content showed a general trend towards depletion from the river, through the fjord and into the ocean. There was, however, no significant change in protein content. The present results confirm that smolts are naturally 'energy deficient' during downstream migration, and suggest that post-smolts also mobilize energy reserves during their early marine phase, while protein is allocated for somatic growth. Plasma growth hormone (GH) levels increased transiently during passage through the estuary and fjord, with lower levels observed in post-smolts caught off-shore, i.e. in fish which were feeding on marine prey and had adapted to the marine environment. These physiological changes may confer substantial selective advantages during the critical early marine phase of anadromous salmonids, and hence are adaptive for long-term survival in sea water. ?? 2003 The Fisheries Society of the British Isles.

Stefansson, S. O.; Bjornsson, B. Th.; Sundell, K.; Nyhammer, G.; McCormick, S. D.

2003-01-01

71

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.

2010-01-01

72

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

PubMed Central

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

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

2011-01-01

73

[Strong stem effect and physiological characteristics of rice plant under rice-duck farming].  

PubMed

A field plot comparison experiment was conducted to study the strong stem effect and physiological characteristics of rice plant under rice-duck farming. The results showed that under rice-duck farming, the morphology of rice plant changed obviously, and the carbohydrate content and C/N ratio of the plant as well as the dry matter output from rice stem increased significantly, due to the activities of duck in paddy field. In the meantime, the length of basal internodes decreased by 2. 88%, while the stem diameter, stem mechanical strength, and stem lodging resistant index increased by 64.90%, 11.78%, and 10.95%, respectively. Rice-duck farming increased the root mass and root vitality in deeper soil layers, and decreased the proportion of black roots by 16.63%. It was indicated that rice-duck farming benefited the formation of strong rice stem and increased the stress resistance of rice plant, which would be favorable to the stable and high-yielding of rice. PMID:19288720

Wang, Qiang-sheng; Zhen, Ruo-hong; Ding, Yan-feng; Wang, Shao-hua

2008-12-01

74

Perinatal physiology in cloned and normal calves: physical and clinical characteristics.  

PubMed

The period immediately after birth is a vital time for all newborn calves as the cardiovascular, respiratory, and other organ systems adapt to life ex utero. Reported neonatal mortality rates suggest this period to be especially critical in cloned calves; yet prospective, controlled studies on the physiological status of these calves are lacking. The objectives of this study were to compare neonatal (birth to 48 h of age) physical and clinical characteristics and placental morphology of cloned and embryo transfer control calves delivered by cesarean section after induced labor. All calves were raised under specialized neonatal-care protocols at a large-animal veterinary research and teaching hospital. Cloned calves were similar to controls for many parameters studied. Notable exceptions included developmental delays of important physical adjustment parameters and enlargement of the umbilical region. Placentas associated with cloned calves contained fewer total placentomes, a twofold increase in surface area and mass per placentome, and a shift in placentome morphology toward larger, flatter placentomes. The most striking clinical variations detected in clones were hypoglycemia and hyperfructosemia, both measures of carbohydrate metabolism. Because the placenta is known to be the source of plasma fructose in newborn calves, increased fructose production by the cloned placenta may be an important factor in the etiology of umbilical and cardiac anomalies in clones observed in this and other studies. PMID:17386015

Batchelder, Cynthia A; Bertolini, Marcelo; Mason, Jeffrey B; Moyer, Alice L; Hoffert, Kara A; Petkov, Stoyan G; Famula, Thomas R; Angelos, John; George, Lisle W; Anderson, Gary B

2007-01-01

75

Physiology and molecular characteristics of a pine wilt nematode-trapping fungus, Monacrosporium megalosporum.  

PubMed

We isolated the nematode-trapping fungus Monacrosporium megalosporum from nature and examined its morphology, physiology and molecular characteristics. The nematode-trapping device of this fungus is a three-dimensional network. This fungus captures the pine wilt nematode (Bursaphelenchus xylophilus), but not a non-phytopathogenic nematode that is morphologically similar to B. xylophilus. The phylogenic relationship of the nucleotide sequence of the rDNA ITS region was close to those of M. thaumasium and Geniculifera eudermata, which also have nematode-trapping devices that are three-dimensional networks. Acidic pH inhibited both the liberation and regeneration of protoplasts. Moreover, cytoplasmic granulation of protoplasts was found below pH 6.0. Mycelial growth on agar media was also inhibited below pH 4, but not at pH 9. These results strongly suggest that the activity of this fungus is inhibited by acid rain in the field. Therefore, development of pine wilt disease might be a secondary effect of acid rain. PMID:15386097

Kano, Sanae; Aimi, Tadanori; Masumoto, Seita; Kitamoto, Yutaka; Morinaga, Tsutomu

2004-09-01

76

Effects of Shade Treatments on Photosynthetic Characteristics, Chloroplast Ultrastructure, and Physiology of Anoectochilus roxburghii  

PubMed Central

Anoectochilus roxburghii was grown under different shade treatments–50%, 30%, 20%, and 5% of natural irradiance–to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii.

Shao, Qingsong; Wang, Hongzhen; Guo, Haipeng; Zhou, Aicun; Huang, Yuqiu; Sun, Yulu; Li, Mingyan

2014-01-01

77

Effects of shade treatments on photosynthetic characteristics, chloroplast ultrastructure, and physiology of Anoectochilus roxburghii.  

PubMed

Anoectochilus roxburghii was grown under different shade treatments-50%, 30%, 20%, and 5% of natural irradiance-to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii. PMID:24516523

Shao, Qingsong; Wang, Hongzhen; Guo, Haipeng; Zhou, Aicun; Huang, Yuqiu; Sun, Yulu; Li, Mingyan

2014-01-01

78

Vasopressin and disorders of water balance: the physiology and pathophysiology of vasopressin.  

PubMed

Disorders of water balance are a common feature of clinical practice. An understanding of the physiology and pathophysiology of the key endocrine regulator of water balance vasopressin (VP) is key to diagnosis and management of these disorders. Diabetes insipidus is the result of a lack of VP or (less commonly) resistance to the renal effects of the hormone. Diagnostic testing can clarify aetiology and direct appropriate management. VP production can be associated with hyponatraemia. A comprehensive assessment of cardiovascular status and pharmacological influences are needed in these circumstances to differentiate between primary (inappropriate) and secondary (appropriate) physiological VP production. As with diabetes insipidus, diagnostic testing can help define the aetiology of hyponatraemia and direct appropriate management. Patients with disorders of water balance benefit from a joint clinical and laboratory medicine approach to diagnosis and management. PMID:17761027

Ball, S G

2007-09-01

79

Soil-water characteristic curves for compacted clays  

Microsoft Academic Search

Soil-water characteristic curves (SWCCs) are presented for four compacted clay barrier soils that were prepared at different compaction water contents (dry, wet, and optimum water content) and compactive efforts (standard and modified Proctor). The SWCCs were measured in the laboratory using pressure plate extractors. The shape of the SWCC depends on compaction water content and compactive effort, but compaction water

James M. Tinjum; Craig H. Benson; Lisa R. Blotz

1997-01-01

80

[Effects of nitrogen deposition on leaf physiological and ecological characteristics of Lindera aggregata seedlings].  

PubMed

From June 2010 to July 2011, a pot experiment was conducted to explore the effects of nitrogen deposition on the leaf physiological and ecological characteristics of Lindera aggregate seedlings. Three levels of NH4NO3, i. e., low-N (2 g x m(-2) x a(-1)), medium-N (8 g x m(-2) x a(-1)), and high-N (32 g x m(-2) x a(-1)) , were added to simulate nitrogen deposition, and the seedling leaf photosynthesis, relative chlorophyll content, chlorophyll fluorescence parameters, membrane lipid peroxidation, and antioxidant enzyme activities were determined. After one-year treatment, the daily mean values of the net photosynthetic rate (P)n)) and the maximum net photosynthetic rate (P(n max)) at low, medium and high levels of NH4 NO3 addition were 47.0%, 117.8% and 41.2%, and 82.6%, 191.3% and 152.2% higher than those of the control (no NH4 NO3 addition), respectively, with the highest values at medium level of NH4NO3 addition. The intercellular CO2 concentration, daily mean stomatal conductance, light saturation point, and apparent quantum yield in the three treatments of NH4NO3 addition were all higher than those of the control, and the dark respiration rate was the highest in treatment high-N. The relative chlorophyll content was the highest in treatment medium-N, followed by in treatment high-N, and had no significant difference between treatment low-N and the control. The chlorophyll fluorescence parameters varied with the levels of NH4NO3 addition. The PS II primary chemical efficiency (F(v)/F(m)) and PS II potential activity (F(v)/F(o)) were the lowest in treatment high-N, the superoxide dismutase activity was higher in nitrogen addition treatments than in the control, and the peroxidase activity, malonydialdehyde content, and membrane permeability were the highest in treatment high-N. All the results suggested that nitrogen deposition enhanced the photosynthetic ability of L. aggregata seedlings, with the most obvious effects in treatment medium-N, and altered the other physiological traits of the seedlings to different degrees. PMID:23359938

Wang, Qiang; Jin, Ze-Xin; Peng, Li-Qiong

2012-10-01

81

Demographic, physiologic and radiographic characteristics of COPD patients taking chronic systemic corticosteroids.  

PubMed

Long-term therapy with systemic corticosteroids is not recommended in the treatment of chronic obstructive pulmonary disease (COPD). However, experience demonstrates that some patients receive low dose therapy. Our objective was to describe the demographic, physiologic and radiologic characteristics of COPD patients treated with chronic systemic corticosteroids. We analyzed COPD subjects with GOLD I-IV disease in the COPDGene® study. Subjects were divided into 2 groups based on whether they reported using chronic oral steroids or not; 1264 subjects were included. Fifty-eight (4.5%) reported chronic systemic corticosteroid use. There were no differences in age, race, co-morbid conditions (other than asthma), or body mass index between the groups. There was a greater proportion of GOLD III (41% vs. 26%) and IV (41% vs. 13%) subjects in the group using chronic systemic corticosteroids. This group used more respiratory medications, required more oxygen (2.31 ± 0.21 vs. 0.59 ± 0.05 L/min; p < 0.0001), and walked less distance (245.4 ± 17.4 vs. 367.2 ± 3.9 meters; p < 0.0001). They reported more total (1.7 ± 0.16 vs. 0.62 ± 0.03; p < 0.0001) and severe exacerbations per year (0.41 ± 0.05 vs. 0.18 ± 0.01; p < 0.0001). BODE (5.0 ± 0.3 vs. 2.6 ± 0.1; p < 0.0001), MMRC (3.31 ± 0.19 vs. 1.90 ± 0.04; p < 0.0001) and SGRQ scores (54.9 ± 2.9 vs 53.3 ± 0.6; p < 0.0001) were higher. They also had a higher percentage of emphysema (22.4 ± 1.9 vs. 14.0 ± 0.4;%, p = <0.0001) on CT scan. COPD patients that report using chronic systemic corticosteroids have more severe clinical, physiologic, and radiographic disease. PMID:22292596

Swift, Irene; Satti, Aditi; Kim, Victor; Make, Barry J; Newell, John; Steiner, Robert M; Wilson, Carla; Murphy, James R; Silverman, Edwin K; Criner, Gerard J

2012-02-01

82

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.

Nikolaidis, Pantelis T.; Ingebrigtsen, J?rgen

2013-01-01

83

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

PubMed

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

Nikolaidis, Pantelis T; Ingebrigtsen, Jørgen

2013-01-01

84

Soil–water characteristic curves of Singapore residual soils  

Microsoft Academic Search

Soil–water characteristic curves were obtained for a number of Singapore residual soil samples. Soil samples were obtained from the two main residual soil formations, the Jurong sedimentary formation and the Bukit Timah granitic formation, at various depths. The effect of weathering on the shape of the soil–water characteristic curve is examined. As the test procedure in obtaining the soil–water characteristic

S. S. Agus; E. C. Leong; H. Rahardjo

2001-01-01

85

The physiological characteristics and transcytosis mechanisms of the blood-brain barrier (BBB).  

PubMed

The blood-brain barrier (BBB) is the vessel wall made up of specialized capillary endothelial cells, surrounded by astroglial endfeet and neurons, that govern the exchange of compounds between blood and brain. It protects the brain from harmful compounds potentially present in blood, while it is specifically designed to supply the brain with the required nutrients and to get rid of waste products. The BBB is structurally different from blood capillaries in other tissues. The BBB strictly limits the paracellular exchange of compounds by the so-called tight junctions. Moreover, the capillary endothelial cells contain metabolic enzymes that may convert a compound before entering the brain while transcellular passage across the BBB may be limited or increased by active transport systems. Thus the BBB has an important role in the relationship of the concentration-time profile of compounds in blood and those in the brain. The functionality of the BBB is dynamically regulated, depending on the given conditions. Important examples are changes in BBB functionality that may result in or are brought about by (CNS) disease conditions. All together this indicates the importance of investigations on BBB functionality and resulting transport of compounds for the design and optimization of therapeutic regimens. Thus, BBB investigation is an ever growing and dynamic field studied by pharmacologists, neuroscientists, pathologists, physiologists, and clinical practitioners. This review deals with a general introduction on the physiological characteristics of the BBB, its different transport systems, with particular emphasis on supposed transcytosis mechanisms at the BBB. Specific and detailed information on drug delivery approaches aiming at transcytosis into the brain will be dealt with in other parts of this special issue. PMID:23016638

de Lange, Elizabeth C M

2012-09-01

86

Comparative community physiology: nonconvergence in water relations among three semi-arid shrub communities.  

PubMed

Plant adaptations to the environment are limited, and therefore plants in similar environments may display similar functional and physiological traits, a pattern termed functional convergence. Evidence was examined for functional convergence among 28 evergreen woody shrubs from three plant communities of the semi-arid winter rainfall region of southern California. Both leaf and water relations traits were examined, including seasonal stomatal conductance (gs), specific leaf area (SLA), leaf specific conductivity (Kl), seasonal water potential (Psi w), stem cavitation resistance (Psi 50), and xylem density. Species display community-specific suites of xylem and leaf traits consistent with different patterns of water use among communities, with coastal sage scrub species utilizing shallow pulses of water, Mojave Desert scrub species relying on deeper water reserves, and chaparral species utilizing both shallow and deep moisture reserves. Communities displayed similar degrees of water stress, with a community-level minimum Psi w (Psi wmin) of c. -4.6 Mpa, similar to other arid communities. Pooled across sites, there was a strong correlation between Psi wmin and xylem density, suggesting that these traits are broadly related and predictive of one another. This comparative community physiology approach may be useful in testing hypotheses of functional convergence across structurally similar semi-arid communities. PMID:18627498

Jacobsen, Anna L; Pratt, R Brandon; Davis, Stephen D; Ewers, Frank W

2008-01-01

87

Rice root growth and physiological responses to SRI water management and implications for crop productivity  

Microsoft Academic Search

This paper reports on several research findings on rice root responses, in terms of growth and physiology, manifested when\\u000a applying System of Rice Intensification water management principles under semi-field and field conditions, in conjunction\\u000a with variations in plant density and microbial density in the soil. The research aimed to learn about causal relationships,\\u000a if any, between rice root and shoot

Abha MishraVilas; Vilas M. Salokhe

2011-01-01

88

Physiological modelling of the response of Kocuria rosea exposed to changing water activity  

Microsoft Academic Search

Physiological effects of NaCl concentration (equivalent water activities, aw, 1 to 0.87) were investigated with the moderately halophilic and piezotolerant bacterium, Kocuria rosea (formerly Micrococcus roseus), grown in bacteriological peptone\\/yeast extract broth. This bacterium, which was isolated from open shallow seawater, can grow in 150 g NaCl l-1 (optimum NaCl concentration: 30 g l-1, aw=0.984) and under 207 MPa of hydrostatic pressure. The effects of

Phillip C. Wright; Tsuyoshi Tanaka

2002-01-01

89

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

90

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

91

Why Do We Teach Physiology the Way We Do? An Analysis of National Characteristics.  

ERIC Educational Resources Information Center

Presents invited reports that express the personal views of physiologists on the historical influences of physiology education in their countries. Includes reports from Argentina, Australia, Germany, Hungary, India, the Netherlands, Switzerland, and the United Arab Emirates. (DDR)

Rodriguez, Ricardo R.; Sefton, Ann Jervie; Silbernagl, Stefan; Monos, Emil; Nayar, Usha; Bouman, Lennart N.; Baumann, Fritz; Das, Mandira; Lammers, Wim J. E. P.; Lanphear, J. H.

1998-01-01

92

Highly aligned lipid membrane systems in the physiologically relevant "excess water" condition.  

PubMed Central

The "excess water" condition in biologically relevant systems is met when a membrane mesophase coexists with excess bulk water. Further addition of water to such a system results in no change to any of the system's physical properties (e.g., transition temperature, repeat spacing, and structural mesophases). Moreover, because biological membranes are anisotropic systems, many of their properties are best studied using aligned samples. Although model membrane systems are routinely aligned, they have traditionally been hydrated with water vapor. It is well known that membranes exposed to water vapor at 100% humidity do not imbibe the same quantity of water as a sample in contact with liquid water. As such, membranes that have been hydrated with water vapor have physical properties different from those of membranes dispersed in water. Because of this shortcoming, aligned membranes have not been utilized to their full potential. Here we present a novel and simple method of aligning model membrane systems under conditions of excess water, which will make possible, for the first time, a variety of techniques (e.g., neutron and x-ray diffraction, nuclear magnetic resonance, electron spin resonance, attenuated total reflection infrared spectroscopy, etc.) for studying such systems under physiologically relevant conditions. In addition, when dealing with samples of limited availability, the system allows for the conditions (buffer pH and ionic strength) to be altered without any effect on the sample's alignment. Images FIGURE 1

Katsaras, J

1997-01-01

93

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

PubMed

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

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

2013-04-15

94

Surface water characteristics in NCEP global spectral model and reanalysis  

Microsoft Academic Search

Characteristics of the National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP\\/NCAR) reanalysis surface water budget are compared to the surface water budget characteristics in a long-term simulation with the NCEP global spectral model (GSM) used in the reanalysis. There are many geographic similarities. There are a few differences though, mainly because the reanalysis has a source

J. O. Roads; S.-C. Chen; M. Kanamitsu; H. Juang

1999-01-01

95

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

PubMed

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

2012-09-01

96

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

USGS Publications Warehouse

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. ?? 2011 The Fisheries Society of the British Isles.

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

2011-01-01

97

Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.  

PubMed

The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P < 0.005). Significant decreases in skin temperature, sweat rate, heart rate, and heat storage was also noted in the HI vs. the CO trials. Tolerance time in the HI exposure were longer than in the CO exposure (only 12 subjects in the CO trial endured the entire heat exposure session, as opposed to all 17 subjects in the HI group). It is concluded that hand immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods. PMID:18478254

Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

2008-09-01

98

Characteristics of Water Exchange in Taihu Lake of China  

Microsoft Academic Search

Water exchange is an important hydrodynamic character for the study of the environmental capacity of large water bodies. An enhanced understanding and better characterization of the exchange ability has fundamental significance in studying the transport of contamination and the eutrophication of large shallow lakes. In this research, a relation matrix is set up to describe the characteristics of water exchange

Y. Gao; Q. Q. Liu

2011-01-01

99

Fish Physiology, Toxicology, and Water Quality. Proceedings of the Eighth International Symposium, Chongqing, China, October 12-14, 2004.  

National Technical Information Service (NTIS)

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:...

D. Randall D. Y. M. Mandy

2006-01-01

100

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

PubMed

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

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

2014-09-01

101

Dynamic characteristics of gas-water interfacial plasma under water  

SciTech Connect

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

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

2012-06-15

102

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.

Talukdar, Dibyendu

2013-01-01

103

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

PubMed

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

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

2014-06-15

104

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

PubMed

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

2014-01-01

105

Physiological Effects of 1-Methylcyclopropene on Well-Watered and Water-Stressed Cotton Plants  

Microsoft Academic Search

The current study investigated the effect of 1-methylcyclopropene (1-MCP), an ethylene inhibiting compound, in alleviating\\u000a the detrimental effect of drought on cotton plants. The experiment was conducted in a growth chamber in 2006 and 2007. Treatments\\u000a consisted of (T1) an untreated control well-watered, (T2) 1-MCP at 10 g ai\\/ha well-watered, (T3) an untreated control water-stressed,\\u000a and (T4) 1-MCP at 10 g ai\\/ha

Eduardo M. KawakamiDerrick; Derrick M. Oosterhuis; John L. Snider

2010-01-01

106

Characteristics of Composts: Moisture Holding and Water Quality Improvement.  

National Technical Information Service (NTIS)

The objective of this study was investigation of the potential beneficial use of compost manufactured topsoil in highway rights-of-way in Texas. The water holding capacity and the physical, chemical and microbiological characteristics of composted manures...

C. J. Kirchhoff J. F. Malina M. Barrett

2003-01-01

107

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

108

The water adsorption characteristics of charged phospholipids  

Microsoft Academic Search

The hydration isotherms of the negatively charged phospholipids, egg phosphatidic acid, bovine heart cardiolipin and two phosphatidylserines as well as one positively charged phospholipid, 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine, have been obtained gravimetrically. The presence of an electrical charge on these phospholipids does not, in itself, determine whether the water binding to the phospholipids is ‘strong’ or ‘weak’. Interestingly, hysteresis effects were present for

Gordon L. Jendrasiak; Ralph L. Smith; Walter Shaw

1996-01-01

109

Electrical and optical characteristics of water under high electric stress  

Microsoft Academic Search

In order to determine the electrical characteristics of water under high electric stress, we have measured the current-electric field (I-E) characteristics of distilled water with a resistivity of 200 k?cm, up to electric field intensities of 1 MV\\/cm. The gap between a 1.7 mm diameter sphere and a plane stainless steel electrodes was varied between 50 ?m to 400 ?m.

S. Katsuki; R. P. Joshi; M. Laroussi; F. Leipold; K. H. Schoenbach

2002-01-01

110

Coal-water slurry atomization characteristics  

SciTech Connect

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

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

1994-04-01

111

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

SciTech Connect

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

Pegg, W.J.

1984-01-01

112

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

PubMed

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

2011-02-01

113

Spectral reflectance and radiance characteristics of water pollutants  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

114

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

NSDL National Science Digital Library

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

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

2003-12-01

115

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

PubMed

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

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

2014-06-01

116

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

PubMed Central

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

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

2014-01-01

117

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

PubMed

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+ and divalent ions (Ca2+ and Mg2+). The organism was microaerophilic and tolerated 300 microM sulfide without a decrease in the rate of CO2 incorporation. Growth and CO2 incorporation occurred within the temperature range of 10 to 35 degrees C, with both optimal at 25 degrees C. At the in situ pressure of 250 atm. the rate of CO2 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. PMID:7054142

Ruby, E G; Jannasch, H W

1982-01-01

118

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

Code of Federal Regulations, 2011 CFR

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

2014-01-01

119

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

2012-03-01

120

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

NASA Technical Reports Server (NTRS)

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

Greenleaf, John E.

1984-01-01

121

Hybrid Embryonic Stem Cell-Derived Tetraploid Mice Show Apparently Normal Morphological, Physiological, and Neurological Characteristics  

PubMed Central

ES cell-tetraploid (ES) mice are completely derived from embryonic stem cells and can be obtained at high efficiency upon injection of hybrid ES cells into tetraploid blastocysts. This method allows the immediate generation of targeted mouse mutants from genetically modified ES cell clones, in contrast to the standard protocol, which involves the production of chimeras and several breeding steps. To provide a baseline for the analysis of ES mouse mutants, we performed a phenotypic characterization of wild-type B6129S6F1 ES mice in relation to controls of the same age, sex, and genotype raised from normal matings. The comparison of 90 morphological, physiological, and behavioral parameters revealed elevated body weight and hematocrit as the only major difference of ES mice, which exhibited an otherwise normal phenotype. We further demonstrate that ES mouse mutants can be produced from mutant hybrid ES cells and analyzed within a period of only 4 months. Thus, ES mouse technology is a valid research tool for rapidly elucidating gene function in vivo.

Schwenk, Frieder; Zevnik, Branko; Bruning, Jens; Rohl, Mathias; Willuweit, Antje; Rode, Anja; Hennek, Thomas; Kauselmann, Gunther; Jaenisch, Rudolf; Kuhn, Ralf

2003-01-01

122

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

Microsoft Academic Search

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

Vliet van T; C. Primo Martin

2011-01-01

123

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

PubMed

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

2012-09-01

124

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

125

Anthropometric and physiological characteristics of young soccer players according to their playing positions: relevance for competition success.  

PubMed

Lago-Peñas, C, Casais, L, Dellal, A, Rey, E, and Domínguez, E. Anthropometric and physiological characteristics of young soccer players according to their playing positions: relevance for competition success. J Strength Cond Res 25(12): 3358-3367, 2011-The aim of this study was to establish the anthropometric and physiological profiles of young soccer players according to their playing position and to determine their relevance for competition success. Three hundred and twenty-one young male soccer players participated in the study. Players, age 15.63 (±1.82) years, range 12-19 years, were classified into the following groups: Goalkeepers (n = 35), Central Defenders (n = 53), External Defenders (n = 54), Central Midfielders (n = 61), External Midfielders (n = 46), and Forwards (n = 72). The anthropometric variables of participants (height, weight, body mass index, 6 skinfolds, 4 diameters, and 3 perimeters) were measured. Also, their somatotype and body composition (weights and percentages of fat, bone, and muscle) were calculated. Participants performed the 20-m progressive run test to estimate their relative VO(2)max, a sprint test (30 m flat), and 3 jump tests (squat jump, countermovement jump, and Abalakov test). External Midfielders were the leanest and shortest. In contrast, Central Defenders and Goalkeepers were found to be the tallest and heaviest players. They also had the largest fat skinfolds. In general, the results show that heavier and taller young soccer players performed better in vertical jumps and 30-m sprint, whereas leaner players performed better in the 20-m progressive run test. Players were classified into 2 groups according to the final ranking of their teams at the end of the season. Players from successful teams performed slightly better than players from unsuccessful teams in the physiological test, but these differences were not statistically significant. Moreover, players from successful teams were found to be leaner and more muscular than their unsuccessful counterparts. PMID:22080317

Lago-Peñas, Carlos; Casais, Luis; Dellal, Alexandre; Rey, Ezequiel; Domínguez, Eduardo

2011-12-01

126

Spray Characteristics Determination of Water Mist for Suppressing Pool Fire  

NASA Astrophysics Data System (ADS)

To optimize the design of a water mist fire suppression system or to provide input data and validation data for field models, the characteristics of the water mist field are needed. This data typically consists of the distribution of droplet sizes and velocities. In this research a LS2000 Laser Sizer has been proposed to simultaneously determine spray characteristics of 408 kinds of self-developed nozzles for fire suppression. The results of LS2000 Laser Sizer measurements to characterize the water mist produced by nozzles for suppressing pool fire are presented. These data can provide a foundation to the design and optimization of additive-containing WMFSS. To explore the effect of the water pressure on the droplet size distribution and spray velocity, data from three typical pressures of 0.9MPa, 1.2MPa and 1.5MPa have been obtained. With the measured average size and distribution of droplets, a comparison between three nozzles was made in the pressure of 1.5MPa to investigate the influence of the nozzle design parameters on atomizing characteristics. The results show that representative size of droplets decreases slightly and the water flow rate increases with the water pressure to the nozzle head Pw, and the droplet velocity of water mist is approximately directly proportional to Pw. The trends that the nozzles with the larger D32 have a wider range of droplet diameter distribution and their volume fraction curves shift towards the large diameter direction are also found in measurements. This will be favorable to the extinguishment of kerosene pool fire. The water flux density distribution results demonstrated that the water flux density over the cross section was very non-uniform when the water mist nozzle is improperly designed.

Zheng, Li G.; Yu, Ming G.; Yu, Shui J.; Liu, Zhi C.

2007-06-01

127

Effect of water compressibility on nonstationary characteristics of hydraulic turbines  

NASA Astrophysics Data System (ADS)

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

Kurzin, V. B.

2013-09-01

128

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

PubMed

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

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

2013-11-01

129

Distribution and Physiological Characteristics of Hyperthermophiles in the Kubiki Oil Reservoir in Niigata, Japan  

PubMed Central

The distribution of culturable hyperthermophiles was studied in relation to environmental conditions in the Kubiki oil reservoir in Japan, where the temperature was between 50 and 58°C. Dominant hyperthermophilic cocci and rods were isolated and shown to belong to the genera Thermococcus and Thermotoga, respectively, by 16S rDNA analyses. Using the most-probable-number method, we found that hyperthermophilic cocci were widely distributed in several unconnected fault blocks in the Kubiki oil reservoir. In 1996 to 1997, their populations in the production waters from oil wells were 9.2 × 103 to 4.6 × 104 cells/ml, or 10 to 42% of total cocci. On the other hand, hyperthermophilic rods were found in only one fault block of the reservoir with populations less than 10 cells/ml. Dominant Thermococcus and Thermotoga spp. grew at reservoir temperatures and utilized amino acids and sugars, respectively, as sole carbon sources. While organic carbon was plentiful in the environment, these hyperthermophiles were unable to grow in the formation water due to lack of essential nutrients. Concentrations of some organic and inorganic substances differed among fault blocks, indicating that the movement of formation water between fault blocks was restricted. This finding suggests that the supply of nutrients via fluid current is limited in this subterranean environment and that the organisms are starved in the oil reservoir. Under starved conditions at 50°C, culturable cells of Thermococcus sp. remained around the initial cell density for about 200 days, while those of Thermotoga sp. decreased exponentially to 0.01% of the initial cell density after incubation for the same period. The difference in survivability between these two hyperthermophiles seems to reflect their populations in the fault blocks. These results indicate that hyperthermophilic cocci and rods adapt to the subterranean environment of the Kubiki oil reservoir by developing an ability to survive under starved conditions.

Takahata, Yoh; Nishijima, Miyuki; Hoaki, Toshihiro; Maruyama, Tadashi

2000-01-01

130

Effects of de-icing salt on ground water characteristics.  

PubMed

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

O'Brien, J E; Majewski, J C

1975-01-01

131

Ammonia pollution characteristics of centralized drinking water sources in China.  

PubMed

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

2012-01-01

132

Significance of Pigment Characteristics of Phytoplankton in Water Quality Estimating  

Microsoft Academic Search

Data on water bodies with different trophic status in the Upper Volga basin are used to analyze the relationship between the algological and pigment characteristics of blue-green alga development. The examined relationships for the phytoplankton of highly eutrophic Lake Nero are shown to feature higher correlation coefficients as compared with meso- and mesoeutrophic reservoirs.

L. E. Sigareva; O. A. Lyashenko

2004-01-01

133

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.

Maeshima, Masayoshi

2014-01-01

134

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

PubMed

The plasma membrane-associated Ca(2+)-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

Tanaka, Natsuki; Kato, Mariko; Tomioka, Rie; Kurata, Rie; Fukao, Yoichiro; Aoyama, Takashi; Maeshima, Masayoshi

2014-04-01

135

Influence of AM fungi on the growth and physiological status of Erythrina variegata Linn. grown under different water stress conditions  

Microsoft Academic Search

The present study investigated the effects of arbuscular mycorrhizal (AM) fungus, Glomus mosseae on the growth and physiology state of Erythrina variegata Linn, grown in sandy loam soil with four water stress levels viz. ?0.06MPa (well watered\\/control), ?1.20MPa (mild), ?2.20MPa (moderate) and ?3.20MPa (severe) in a completely randomized design. Plants were harvested after 90 days (60 days after stress induction)

P. T. Manoharan; V. Shanmugaiah; N. Balasubramanian; S. Gomathinayagam; Mahaveer P. Sharma; K. Muthuchelian

2010-01-01

136

Physiological and photosynthetic responses of melon ( Cucumis melo L.) seedlings to three Glomus species under water deficit  

Microsoft Academic Search

Melon (Cucumis melo L.)—an important horticultural crop that is often cultivated in simply equipped solar greenhouses in northwestern regions\\u000a of China—usually suffers under poor water management. Arbuscular mycorrhizal (AM) symbiosis can play a major role in enhancing\\u000a drought tolerance. Plant growth, physiological, and photosynthetic responses of melon plants inoculated with three Glomus species under two water conditions were investigated. Results

Zhi Huang; Zhirong Zou; Chaoxing He; Zhongqun He; Zhibin Zhang; Jianming Li

2011-01-01

137

Retrieving crop physiological parameters and assessing water deficiency using MODIS data during the winter wheat growing period  

Microsoft Academic Search

The potential of moderate-resolution imaging spectroradiometer (MODIS) time-series in monitoring crop condition was examined in the Weishan Irrigation Zone along a downstream reach of the Yellow River, China. First, MODIS-derived spectral indices, including the normalized difference water index (NDWI) and normalized difference vegetation index (NDVI), were employed to retrieve the crop physiological parameters (such as vegetation water content and dry

Yonghong Yi; Dawen Yang; Daoyi Chen; Jingfeng Huang

2007-01-01

138

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

PubMed

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

2010-08-01

139

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

PubMed Central

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

Series, F; Cote, C; Simoneau, J A; Gelinas, Y; St Pierre, S; Leclerc, J; Ferland, R; Marc, I

1995-01-01

140

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

PubMed

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

Withers, Philip C; Cooper, Christine E

2014-01-01

141

Characteristics and formation causes of Qingdao Cold Water Mass  

NASA Astrophysics Data System (ADS)

In this work, the main characteristics of the Qingdao Cold Water Mass were studied by using “the comparison analysis method” based on 1980 temperature, salinity and dissolved oxygen data on the western South Yellow Sea. The formation cause of the water mass was analyzed based on February of 1959 temperature and salinity data for this area and on some other authors' studies. The results showed that the Qingdao Cold Water Mass has growing and vanishing processes: appears in the last ten days of March; has stable partern in April; is biggest in its area in May; becomes small in its area in June; vanishes in July. It comes from the northern Shandong Coastal Water and is characterized by low temperature and salinity and high dissolved oxygen. The mass is formed under the joint effects of anticyclonic circulation and solar radiation.

Zhang, Qi-Long; Liu, Xing-Quan; Cheng, Ming-Hua; Yu, Xin-Sheng

2002-12-01

142

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

Microsoft Academic Search

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

Spyros K. Golfinopoulos; George B. Arhonditsis

2002-01-01

143

Characteristics of water and carbon balance in moso bamboo forests  

NASA Astrophysics Data System (ADS)

Water and carbon cycles in mountainous areas can have considerable impacts on our available nature resources such as water resources and timber production. Thus, it is indispensable to clarify the difference of water and carbon balances between different types of forested ecosystems. Recently, bamboo forests have been expanding by replacing surrounding vegetation such as coniferous and broad-leaved forests in eastern Asian countries. It has been speculated that the replacements by bamboo forests could alter the vegetation water and carbon cycles. However, our knowledge for the bamboo forests was still limited due to lack of applicable methodology based on a field measurement. To clarify the potential impacts of bamboo expansion on water and carbon cycles, our previous study established optimal and effective design for assessing bamboo forest water use (ie, transpiration) based on sap flux measurements. Using the method, we quantified stand-scale transpiration in bamboo forests and coniferous forests in Taiwan. Consequently, we found significantly larger transpiration in bamboo forests compared with those of surrounding vegetation due to larger canopy conductance in bamboo forests. The unique characteristics of the water use accompanied larger carbon assimilation and soil CO2 efflux in bamboo forests.

Kume, T.; Laplace, S.; Tseng, H.; Hsieh, Y.; Wey, T.; Komatsu, H.

2013-12-01

144

Soil-water characteristic curves for compacted clays  

SciTech Connect

Soil-water characteristic curves (SWCCs) are presented for four compacted clay barrier soils that were prepared at different compaction water contents (dry, wet, and optimum water content) and compactive efforts (standard and modified Proctor). The SWCCs were measured in the laboratory using pressure plate extractors. The shape of the SWCC depends on compaction water content and compactive effort, but compaction water content is more important. Compaction at higher compaction water content or with greater compactive effort results in larger air entry. Also, clays with higher plasticity index have greater air-entry suction. Changes in the shape of the SWCC are consistent with changes in pore size that occur by varying compaction conditions and with the mineralogical composition of the soils. These changes in the SWCC also are reflected in the van Genuchten and Brooks-Corey parameters, which were obtained from least-squares fits to the SWCC data. Regression equations are presented that can be used to estimate the van Genuchten parameters {alpha} and n from compaction water content, compactive effort, and plasticity index.

Tinjum, J.M. [CH2M Hill, Inc., Denver, CO (United States); Benson, C.H.; Blotz, L.R. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering

1997-11-01

145

Discharge Characteristics of DC Arc Water Plasma for Environmental Applications  

NASA Astrophysics Data System (ADS)

A water plasma was generated by DC arc discharge with a hafnium embedded rod-type cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process.

Li, Tianming; Sooseok, Choi; Takayuki, Watanabe

2012-12-01

146

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

PubMed

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

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

2013-08-01

147

Growth and physiological state of the microalgae Phaeodactylum tricornutum Bohlin (Bacillariophyta) in the water taken from peter the Great Bay  

NASA Astrophysics Data System (ADS)

Bioassay of water from different parts of the Peter the Great Bay using microalgae P. tricornutum revealed that water quality influences not only the growth but also the physiological state of the microalgae. There was no difference in the cell size between control and experimental cultures. Inhibition of microalgae growth was revealed in water with low phosphates concentration, for example, in the Marine Reserve. High phosphates concentration and moderate organic pollution caused the stimulation of miñroalgae growth in such sites as the Tumen, the Partizanskaya and the Vtoraya rechka rivers mouths.

Zhuravel, Elena; Markina, Zhanna; Aizdaicher, Nina

2009-09-01

148

Underwater polarization characteristics and their impact on water visibility  

NASA Astrophysics Data System (ADS)

In this paper we examine the impact of measured underwater polarization characteristics on visibility. Underwater characteristics were measured both in the principal plane and outside the principal plane, with data collected during several cruises in the Chesapeake/Virginia and New York Harbor/Hudson River areas using a multi-angular hyperspectral sensor system. This system, recently developed by us, consists of three hyperspectral Satlantic radiance sensors, each with a polarizer positioned in front of it, and with polarization axes aligned at 0, 90 and 45 deg. Underwater measurements are made with scattering angles from 0-180 degrees with respect to the solar illumination. At the same time as the hyperspectral measurements are made, the inherent optical properties such as absorption and attenuation were also recorded. The waters studied varied from clear open ocean water with attenuation of less than 0.25m-1 at 550nm c (550), to turbid coastal waters with a c(550) of more than 4m-1. In order to examine the extent that polarization techniques can help to improve underwater visibility in these types of field conditions, we computed the related modulation transfer functions from the polarized field measurements, and included the examination of the impact of scattered polarized veiling light, inherent in the field data. Various water parameters are then explored to examine the impact of the polarization of the background light in the principal plane on underwater visibility.

Zhou, Jing; Tonizzo, Alberto; Gilerson, Alex; Gross, Barry; Moshary, Fred; Ahmed, Sam

2010-04-01

149

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

Microsoft Academic Search

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

P. Quinlan; Laurence Aspinall

1997-01-01

150

Regurgitant flow field characteristics of the St. Jude bileaflet mechanical heart valve under physiologic pulsatile flow using particle image velocimetry.  

PubMed

The regurgitant flow fields of clinically used mechanical heart valves have been traditionally studied in vitro using flow visualization, ultrasound techniques, and laser Doppler velocimetry under steady and pulsatile flow. Detailed investigation of the forward and regurgitant flow fields of these valves can elucidate a valve's propensity for blood element damage, thrombus formation, or cavitation. Advances in particle image velocimetry (PIV) have allowed its use in the study of the flow fields of prosthetic valves. Unlike other flow field diagnostic systems, recent work using PIV has been able to relate particular regurgitant flow field characteristics of the Bjork-Shiley Monostrut valve to a propensity for cavitation. In this study, the regurgitant flow field of the St. Jude Medical bileaflet mechanical heart valve was assessed using PIV under physiologic pulsatile flow conditions. Data collected at selected time points prior to and after valve closure demonstrated the typical regurgitant jet flow patterns associated with the St. Jude valve, and indicated the formation of a strong regurgitant jet, in the B-datum plane, along with twin vortices near the leaflets. Estimated ensemble-average viscous shear rates suggested little potential for hemolysis when the hinge jets collided. However, the vortex motion near the occluder tips potentially provides a low-pressure environment for cavitation. PMID:12940907

Manning, Keefe B; Kini, Vinayak; Fontaine, Arnold A; Deutsch, Steven; Tarbell, John M

2003-09-01

151

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

PubMed

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

Sun, Hongyu; Wu, Shu Hui

2008-08-21

152

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

NASA Astrophysics Data System (ADS)

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

Gharun, Mana; Turnbull, Tarryn; Adams, Mark

2014-05-01

153

Characteristics of Water Ingress in Norwegian Subsea Tunnels  

NASA Astrophysics Data System (ADS)

Water ingress represents one of the main challenges in subsea tunnelling, particularly when this occurs in sections with poor rock mass quality. This paper is discussing the main characteristics of water ingress in subsea hard rock tunnels based on the experience from almost 50 such tunnels that have been built in Norway. Following a brief description of the geological conditions and the basic design of the subsea tunnels, pre-construction investigations and investigations during excavation are discussed with particular emphasis on prediction of water ingress. Two cases with particularly difficult conditions; the Bjorøy tunnel and the Atlantic Ocean tunnel, are discussed in detail. In these cases, large water inflow with pressure of up to 2.4 MPa was encountered at major faults/weakness zones during excavation, and special procedures were required to cope with the problems. Based on the experience from the Norwegian projects, it is concluded that continuous follow-up by experienced engineering geologists, probe drilling with the drilling jumbo and pre-grouting where required are the most important factors for coping with water ingress and ensuring stability.

Nilsen, Bjørn

2014-05-01

154

Characteristic Analysis of AC Plasma Arc in Water  

NASA Astrophysics Data System (ADS)

An experimental system of AC arc discharge in water was designed with pole-pole electrodes and a peak voltage of 1500 V and a test circuit was set up using virtual instrument technology. The mechanism of an AC plasma arc generated in water was analyzed. The voltage-current characteristic of the AC plasma arc was obtained from the waveform. The temperature characteristic was tested with a spectrum diagnosis system, and the effect of different electrode materials on the striking voltage and peak current was analyzed. The results show that when a power supply of 6 kW is applied on electrodes with a gap of 2 mm in water, the striking voltage is from 900 V to 1300 V, the arc voltage is from 40 V to 100 V, the arc current is from 2 A to 7 A, and the zero rest period is from 1 ms to 2 ms. In addition, the arc voltage and current are different for electrodes in aluminum, copper and stainless steel. The arc voltage is lower and the current is higher for an aluminum electrode than those for copper and stainless steel ones. The highest temperature of the arc is 7643 K.

Zhou, Enping; Yang, Jiaxiang; Ma, Fenglian

2011-02-01

155

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

156

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

PubMed

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

2010-03-01

157

Thrust Characteristics of Water Rocket and Their Improvement  

NASA Astrophysics Data System (ADS)

The propulsive characteristics of water rockets are analyzed theoretically and experimentally. The unsteady thrust force acting on a PET bottle and the air pressure inside the bottle are measured simultaneously by the thrust test stand we have developed. The semi-empirical thrust history is obtained utilizing the air pressure history and it is compared with the measured thrust history. The results show qualitative agreement. The observation of the flow inside bottle by a high-speed video camera shows that the air precedes water when it is about to be discharged entirely. We have developed a flow regulator attached to the nozzle cap to reduce the precursor air discharge that is considered as a result of the swirling flow inside the bottle. The experimental results show that the air discharge and the body vibration are suppressed effectively.

Watanabe, Rikio; Tomita, Nobuyuki; Takemae, Toshiaki

158

Measurement of "turbidity" and related characteristics of natural waters  

USGS Publications Warehouse

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

Pickering, R. J.

1976-01-01

159

Characteristics of Electrode-Water-Electrode Discharge and its Application to Water Treatment  

NASA Astrophysics Data System (ADS)

Atmospheric air discharge above the surface of water is an effective method for water treatment. The leakage current and Joule heating of water are reduced by the air gap, which raises the energy efficiency of the water treatment. However, the application of this kind of discharge is limited by a pair of conflicting factors: the chemical efficiency grows as the discharge gap distance decreases, while the spark breakdown voltage decreases as the gap distance decreases. To raise the spark breakdown voltage and the chemical efficiency of atmospheric pressure water surface discharge, both the high-voltage electrode and the ground electrode are suspended above the water surface to form an electrode-water-electrode discharge system. For this system, there are two potential discharge directions: from one electrode to another directly, and from the electrodes to the water surface. The first step in utilizing the electrode-water-electrode discharge is to find out the discharge direction transition criterion. In this paper, the discharge direction transition criterions of spark discharge and streamer discharge are presented. By comparing the discharge characteristics and the chemical efficiencies, the discharge propagating from the electrodes to the water surface is proved to be more suitable for water treatment than that propagating directly between the electrodes.

Wang, Xiaoping; Li, Zhongjian; Zhang, Xingwang; Lei, Lecheng

2014-05-01

160

Characteristic mega-basin water storage behavior using GRACE  

PubMed Central

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

Reager, J T; Famiglietti, James S

2013-01-01

161

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

PubMed

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

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

2001-09-01

162

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

PubMed

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

2014-09-01

163

Physiological responses of cobia Rachycentron canadum following exposure to low water and air exposure stress challenges  

Microsoft Academic Search

Prevention is the most viable disease management strategy in aquaculture, and prevention is primarily driven by strategies to avoid or minimize the effects of stress. Unfortunately, there is little information available regarding the stress physiology of emerging aquaculture species or appropriate experimental stressing protocols for these fishes, and thus very little context in which to evaluate mitigation strategies. Accordingly, the

J. Trushenski; M. Schwarz; R. Takeuchi; B. Delbos; L. A. Sampaio

2010-01-01

164

Physiological and morphological responses to water stress in two Acacia species from contrasting habitats  

Microsoft Academic Search

Summary Container-grown seedlings of Acacia tortilis Forsk. Hayne and A. xanthophloea Benth. were watered either every other day (well watered) or every 7 days (water-stressed) for 1 year in a greenhouse. Total plant dry mass (Tdm), carbon allocation and water relations were measured monthly. Differ- ences in leaf area (LA) accounted for differences in Tdm be- tween the species, and

D. O. OTIENO; M. W. T. SCHMIDT; S. ADIKU; J. TENHUNEN

165

Spectral characteristics analysis of red tide water in mesocosm experiment  

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

166

Definition and characteristics of the water abundant season in Korea  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

167

Physiological Adaptations of Salmonid Fishes (Salmo clarki henshawi, Salmo gairdneri, and Oncorhynchus kisutch) to Alkaline Saline Water and Its Toxic Effects.  

National Technical Information Service (NTIS)

Two studies were conducted to determine the physiological adaptations of 3 salmonid fishes to the alkaline, slightly saline waters of Pyramid Lake, NV, and their toxic effects. In the acclimation study, growth rates and blood parameters of fingerling Laho...

D. L. Koch J. Knoll J. Sommer L. Hoffman R. Knoll

1979-01-01

168

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

PubMed

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

2012-12-30

169

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

PubMed

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

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

2013-11-01

170

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.

2013-01-01

171

Optical Characteristics of Phosphorescent Materials with Water-Based Ceramics  

NASA Astrophysics Data System (ADS)

A composite coating approach has been employed to produce phosphorescent materials for emergency exit signs. The coating consists of a reflecting undercoat, a middle coating comprising phosphorescent pigments in a water based ceramic, and a final transparent silica topcoat. The effects of size and amount of pigments in the ceramic based coating on the luminance of the materials was assessed and compared with the Japanese Industrial Standard for safety signboards (JIS Z9107). The luminance increased with the amount of pigment in the coating, and samples with more than 20% exceeded the standard. Luminance 10 times higher than the JIS standard was obtained with 50% phosphorescent pigments. The luminance increased initially with the number of applications of the ceramic based coating but there was no further increase for more than 4 applications. The water-based phosphorescent ceramics developed here are superior in optical characteristics and made entirely of inorganic materials. It is considered that these are excellent materials for phosphorescent emergency exit signs. In addition, the materials can be applied at room temperature for example to metal substrates or by silkscreen printing on tiles, and then calcined at low temperature. This type of processing makes them suitable for a whole range of applications.

Fujita, Akihiro; Kagami, Shinya; Jones, Mark I.

172

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

Microsoft Academic Search

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

Norbert Uehlein

173

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

PubMed

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

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

2013-09-15

174

The effect of air permeability and water vapor permeability of cleanroom clothing on physiological responses and wear comfort.  

PubMed

The function of cleanroom clothing is to protect the product from contamination by people, and to dissipate electrostatic discharge. People in the cleanroom work environment often complain about the discomforts associated with the wearing of cleanroom clothing. The purpose of this study is to investigate the effect of air permeability and water vapor permeability of cleanroom clothing on the subject's physiological and subjective responses. Five male and five female subjects participated in this study. The experimental goal was to simulate the operator's regular tasks in a semiconductor manufacturing cleanroom. Each subject completed three treatment combinations with three different cleanroom clothing types. A three-factor experiment was designed (significance level p = 0.05). The independent variables included gender, cleanroom clothing, and duration. The dependent measures included heart rate, core temperature, skin temperature, micro-climate relative humidity, micro-climate temperature, and subjective responses. A total of 40 min was involved for each treatment condition. The results indicate that skin temperature, micro-climate temperature and micro-climate relative humidity were lower while wearing cleanroom clothing with high air permeability and high water vapor permeability. The significant gender difference was found in skin temperature. As the task time increased, the micro-climate temperature also increased but the micro-climate relative humidity decreased at first and then increased. In addition, the physiological responses showed significant positive correlations with the subjective perception of clothing comfort. The findings of this study may provide useful information for cleanroom clothing design and selection. PMID:24380506

Chen, Te-Hung; Chen, Wan-Ping; Wang, Mao-Jiun J

2014-01-01

175

Sensitivity of terrestrial water and energy budgets to CO2-physiological forcing: an investigation using an offline land model  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

176

Efficiency of Water Use as Influenced by Micrometeorological and Physiological Processes.  

National Technical Information Service (NTIS)

Water-use efficiency (net photosynthesis/evapotranspiration) was studied on sorghum treated with an antitranspirant, phenylmercuric acetate. Short-term studies of 3 to 4 days post-treatment showed that water use efficiency was reduced. Results show that d...

E. T. Kanemasu I. D. Teare W. L. Powers J. W. Sij L. J. Brun

1973-01-01

177

Physiological responses to water stress in Eucalyptus cloeziana and E. argophloia seedlings  

Microsoft Academic Search

Effects of water stress duration and intensity on gas exchange and leaf water potential were investigated in 7-month-old seedlings of a humid coastal provenance (Gympie) and a dry inland (Hungry Hills) provenance of E. cloeziana F. Muell. and in a dry inland (Chinchilla) provenance of E. argophloia Blakely supplied with 100% (T 100), 70% (T 70), 50% (T 50) of

Michael R. Ngugi; David Doley; Mark A. Hunt; Paul Ryan; Peter Dart

2004-01-01

178

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

Microsoft Academic Search

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

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

2003-01-01

179

Water source as a housing characteristic: Hedonic property valuation and willingness to pay for water  

NASA Astrophysics Data System (ADS)

Using data from a large representative sample of rural households in one region of the Philippines, we estimate the determinants of the rental value of dwellings using the bid-rent approach to the hedonic price model. Our particular interest is in the relative valuation these households place on owning a private source of water and distance to a public or communal source. We find that low-, middle-, and high-income households value an in-house piped water source highly relative to other characteristics of their homes. Middle- and high-income households value a deep well or piped water in the yard, although at a substantially lower level than piped water in the house. It is somewhat surprising to find that, except in the case of high-income families, households appear to gain little or no utility from having a communal source of water, such as a river, lake, or public tap, closer to their homes. As a consequence, public water policies that emphasize improving the quality and proximity of communal sources would be inappropriate for the region represented by this sample.

North, J. H.; Griffin, C. C.

1993-07-01

180

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

PubMed Central

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

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

2012-01-01

181

Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption  

PubMed Central

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

Boone, Michelle

2008-01-01

182

Physiological studies of native cyanobacterial species Lyngbya contorta and Phormidium foveolarum in sewage waste water.  

PubMed

A variety of Cyanobacterial species predominantly ensheathed forms occurs in sewage water receiving areas. A study was conducted to analyse the potential of using native Lyngbya contorta and Phormidium foveolarum isolated from sewage water irrigated soils, for biomass production under sewage waste water. The native Cyanobacterial strains were characterised and changes in their biochemical composition in response to different concentrations of sewage waste water were investigated. Results showed that biomass(3.5-6.6 mg 10 ml?¹, 2.6-5.6 mg 10 ml?¹) and photosynthetic pigment contents increased with incubation time (chlorophyll 1.21-3.09 µg ml?¹, 1.92-9.51 µg ml?¹; carotenoid 20.8-34.8 µg ml?¹, 16.4-32.8 µg ml?¹) and decreased thereafter as nutrients became limiting. On the other hand, soluble proteins, after showing a decline, recovered faster with maximum concentration (42.6-63.3 µg ml?¹ and 59-79.8 µg ml?¹) recorded on day 8. Total carbohydrate content also increased (19.27-31.45 µg ml?¹, 14.1-28.21 µg ml?¹) in response to various concentrations of sewage waste water. The overall response was better for 50% sewage waste water concentration which showed that these native strains were suitable candidates for cultivation after proper dilution. PMID:24813018

Rana, Lalita; Chhikara, Sunil; Dhankhar, Rajesh

2014-05-01

183

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

SciTech Connect

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

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

2000-01-14

184

A Physiological Stimulating Factor of Water Intake during and after Dry Forage Feeding in Large-type Goats  

PubMed Central

When ruminants consume dry forage, they also drink large volumes of water. The objective of this study was to clarify which factor produced when feed boluses enter the rumen is mainly responsible for the marked increase in water intake in the second hour of the 2 h feeding period in large-type goats fed on dry forage for 2 h twice daily. Six large-type male esophageal- and ruminal-fistulated goats (crossbred Japanese Saanen/Nubian, aged 2 to 6 years, weighing 85.1±4.89 kg) were used in two experiments. In experiment 1, the water deprivation (WD) control and the water availability (WA) treatment were conducted to compare changes in water intake during and after dry forage feeding. In experiment 2, a normal feeding conditions (NFC) control and a feed bolus removal (FBR) treatment were carried out to investigate whether decrease in circulating plasma volume or increase in plasma osmolality is mainly responsible for the marked increase in water intake in the second hour of the 2 h feeding period. The results of experiment 1 showed that in the WA treatment, small amounts of water were consumed during the first hour of feeding while the majority of water intake was observed during the second hour of the 2 h feeding period. Therefore, the amounts of water consumed in the second hour of the 2 h feeding period accounted for 82.8% of the total water intake. The results of experiment 2 indicated that in comparison with the NFC control, decrease in plasma volume in the FBR treatment, which was indicated by increase in hematocrit and plasma total protein concentrations, was higher (p<0.05) in the second hour of the 2 h feeding period. However, plasma osmolality in the FBR treatment was lower (p<0.05) than compared to the NFC control from 30 min after the start of feeding. Therefore, thirst level in the FBR treatment was 82.7% less (p<0.01) compared with that in the NFC control upon conclusion of the 30 min drinking period. The results of the study indicate that the increased plasma osmolality in the second hour of the 2 h feeding period is the main physiological stimulating factor of water intake during and after dry forage feeding in large-type goats.

Van Thang, Tran; Sunagawa, Katsunori; Nagamine, Itsuki; Kishi, Tetsuya; Ogura, Go

2012-01-01

185

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.

1994-01-01

186

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

PubMed

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

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

2009-04-01

187

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.

2009-05-01

188

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.

Wright, Patricia A.

2012-01-01

189

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

PubMed

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

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

2006-01-01

190

Studies on the Population Dynamics and Physiological Ecology of Four Species of Fresh-Water Isopods.  

National Technical Information Service (NTIS)

The comparative biology of four species of fresh-water isopods was investigated. Isopods are known to be part of the 'pollution fauna' that can inhabit badly polluted areas. The species studies inhabit a temporaty pond, a drainage ditch, a small permanent...

A. J. Seidenberg S. C. Kendeigh

1970-01-01

191

Effect of benzyl butyl phthalate on physiology and proteome characterization of water celery ( Ipomoea aquatica Forsk.)  

Microsoft Academic Search

This study examined the effect of benzyl butyl phthalate (BBP), a phthalate ester (PAE) and an endocrine disruptor, on water celery, Ipomoea aquatica Forsk., one of the most popular leaf vegetables in Taiwan. After 28 days of cultivation, treatment with 100mgL?1 BBP retarded plant growth and decreased biomass and number of mature leaves and caused the accumulation of proline in

Wen-Ching Chen; Han-Ching Huang; Yei-Shung Wang; Jui-Hung Yen

2011-01-01

192

Effect of benzyl butyl phthalate on physiology and proteome characterization of water celery (Ipomoea aquatica Forsk.).  

PubMed

This study examined the effect of benzyl butyl phthalate (BBP), a phthalate ester (PAE) and an endocrine disruptor, on water celery, Ipomoea aquatica Forsk., one of the most popular leaf vegetables in Taiwan. After 28 days of cultivation, treatment with 100 mgL?¹ BBP retarded plant growth and decreased biomass and number of mature leaves and caused the accumulation of proline in leaves of water celery, but the concentrations of chlorophyll a and b in the leaves remained constant. 2-D gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the proteome of leaf tissue revealed five protein spots with up- and down-regulated expression. The predicted protein XP_001417439 was down-regulated, which explained inhibition of plant growth, and the proteina XP_001417040, calreticulin, GAI-like protein 1, and (-)-linalool synthase were up-regulated, which indicates interference with the cell cycle and protein synthesis, as well as dwarfism of water celery. BBP is a stressor on the growth of water celery, and proteome analysis revealed the up- and down-regulation of genes involved in plant growth with BBP treatment. PMID:21496923

Chen, Wen-Ching; Huang, Han-Ching; Wang, Yei-Shung; Yen, Jui-Hung

2011-07-01

193

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

PubMed

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

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

1994-01-01

194

Characteristics of alveolar bone associated with physiological movement of molar in mice: a histological and histochemical study.  

PubMed

Mouse molars undergo distal movement, during which new bone is formed at the mesial side of the tooth root whereas the preexisting bone is resorbed at the distal side of the root. However, there is little detailed information available regarding which of the bones that surround the tooth root are involved in physiological tooth movement. In the present study, we therefore aimed to investigate the precise morphological differences of the alveolar bone between the bone formation side of the tooth root, using routine histological procedures including silver impregnation, as well as by immunohistochemical analysis of alkaline phosphatase and tartrate-resistant acid phosphatase activity, and immunohistochemical analysis of the expression of the osteocyte markers dentin matrix protein 1, sclerostin, and fibroblast growth factor 23. Histochemical analysis indicated that bone formation by osteoblasts and bone resorption by osteoclasts occurred at the bone formation side and the bone resorption side, respectively. Osteocyte marker immunoreactivity of osteocytes at the surface of the bone close to the periodontal ligament differed at the bone formation and bone resorption sides. We also showed different specific features of osteocytic lacunar canalicular systems at the bone formation and bone resorption sides by using silver staining. This study suggests that the alveolar bone is different in the osteocyte nature between the bone formation side and the bone resorption side due to physiological distal movement of the mouse molar. PMID:23263522

Matsuda, Kie; Haga-Tsujimura, Maiko; Yoshie, Sumio; Shimomura-Kuroki, Junko

2014-01-01

195

[The cellular mechanisms of the physiological action of iodobromide mineral waters].  

PubMed

The experiments on edible frogs have revealed the relationship between the effect of sodium chloride, skin potential difference and micro-components iodide and bromide present in the solution. The results obtained furnish the additional information on the synergistic action of mineral water iodide and bromide on the body. Iodide ions were found to act mainly through inhibition of sodium channels of cellular membranes, while bromide ions are likely to affect Na, K-ATPase. PMID:2336825

Serov, S I; Tereshin, S Iu

1990-01-01

196

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

Microsoft Academic Search

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

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

197

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

PubMed

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

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

2010-01-01

198

Germination characteristics of lakeshore plants under an artificially stabilized water regime  

Microsoft Academic Search

To examine the possibility of the failure of lakeshore plants to germinate under an anthropogenically controlled water regime, we investigated physiological germination responses to temperature and inundation among 25 lakeshore plant species from Lake Kasumigaura, Japan. The requirement of low temperature for dormancy breakage, which is common in spring-germinators, was seen in 14 species. Eight species showed sensitivity to temperature

Jun Nishihiro; Sachiko Araki; Nobuo Fujiwara; Izumi Washitani

2004-01-01

199

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

SciTech Connect

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

Tsai, Baolong.

1989-01-01

200

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

PubMed Central

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

2011-01-01

201

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

PubMed Central

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

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

2010-01-01

202

The thermochemical characteristics of solution of phenol and benzoic acid in water-dimethylsulfoxide and water-acetonitrile mixtures  

NASA Astrophysics Data System (ADS)

The solution of phenol and benzoic acid in water-dimethylsulfoxide (DMSO) and water-acetonitrile (AN) mixtures was studied. As distinct from benzoic acid, the thermodynamic characteristics of solution of phenol sharply change at concentrations corresponding to a change in the character of cluster formation in water-DMSO and water-AN mixtures. Differences in the solvation of phenol and benzoic acid are explained by different mechanisms of the interaction of the solutes with clusters existing in binary mixtures.

Zakharov, A. G.; Voronova, M. I.; Batov, D. V.; Smirnova, K. V.

2011-03-01

203

Relationships between characteristics of interfacial water and human bone tissues.  

PubMed

Water bound in human bone tissues healthy (sample S1) and affected by osteoporosis (sample S2) was investigated by using 1H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial waters at T< 273 K. The 1H NMR spectra of the bound water include two signals which can be assigned to strongly associated typical water (chemical shift of the proton resonance at delta(H) approximately 5 ppm) and weakly associated water at delta(H) approximately 1.4 ppm. Approximately, half of the bound water is in the weakly associated state in S1. A fraction of similar water in S2 is smaller because of the structural difference of the studied samples. The pore size distribution of S2 (in aqueous medium) calculated using the cryoporometry method is characterized by much larger intensity of mesopores and macropores in comparison with that of S1. The total porosity and the surface area of the biostructures (accessible for water molecules and estimated on the basis of the cryoporometry data using a model of cylindrical pores) are larger for S2. Weakly polar chloroform-d has a significant influence on the organization of water in a spongy component of bone tissue. This effect depends on the porosity of the bone matrix and the amounts of CDCl3. PMID:16959475

Gun'ko, V M; Turov, V V; Shpilko, A P; Leboda, R; Jablonski, M; Gorzelak, M; Jagiello-Wojtowicz, E

2006-11-01

204

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

PubMed Central

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

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

2011-01-01

205

Influence of Selected Water Quality Characteristics on the Toxicity of ?-Cyhalothrin and ?-Cyhalothrin to Hyalella azteca  

Microsoft Academic Search

This study was conducted to assess the influence of suspended solids, dissolved organic carbon, and phytoplankton (as chlorophyll\\u000a a) water quality characteristics on ?-cyhalothrin and ?-cyhalothrin aqueous toxicity to Hyalella azteca using natural water from 12 ponds and lakes in Mississippi, USA with varying water quality characteristics. H. azteca 48-h immobilization EC50 values ranged from 1.4 to 15.7 ng\\/L and 0.6

S. Smith Jr; R. E. Lizotte Jr

2007-01-01

206

Discharge and dynamic characteristics of boiling water in laval nozzles  

Microsoft Academic Search

The criterial processing of experimental results, obtained by studying the discharge of hot water into the atmosphere through a Laval nozzle, is proposed. The initial parameters of the water were varied over the range p0=4.9–17.6 bar and t0=119–204°C.

R. S. Gorelik; M. A. Koronkevich; N. S. Safarova; I. R. Shreiber

1978-01-01

207

Discharge and dynamic characteristics of boiling water in laval nozzles  

Microsoft Academic Search

The criterial processing of experimental results, obtained by studying the discharge of hot water into the atmosphere through a Laval nozzle, is proposed. The initial parameters of the water were varied over the range p0=4.9 17.6 bar and t0=119 204°C.

R. S. Gorelik; M. A. Koronkevich; N. S. Safarova; I. R. Shreiber

1978-01-01

208

Well characteristics influencing arsenic concentrations in ground water  

Microsoft Academic Search

Naturally occurring arsenic contamination is common in ground water in the upper Midwest. Arsenic is most likely to be present in glacial drift and shallow bedrock wells that lie within the footprint of northwest provenance Late Wisconsinan glacial drift. Elevated arsenic is more common in domestic wells and in monitoring wells than it is in public water system wells. Arsenic

Melinda L. Erickson; Randal J. Barnes

2005-01-01

209

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

2008-05-01

210

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

Microsoft Academic Search

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

J. S. Sperry; U. G. Hacke

2002-01-01

211

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

PubMed

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

Flerov, B A; Koroleva, E K

1999-01-01

212

Characteristics of the membrane utilized in a compact absorber for lithium bromide–water absorption chillers  

Microsoft Academic Search

This study aims at investigating experimentally and analytically the characteristics and properties of a membrane utilized to design compact absorbers for lithium bromide–water absorption chillers. The main focus of this study are the factors that influence the water vapor transfer flux into a lithium bromide–water solution in confined narrow channels under vacuum conditions, as well as the properties limits for

Ahmed Hamza H. Ali; Peter Schwerdt

2009-01-01

213

Changes of some anti-oxidative physiological indices under soil water deficits among 10 wheat ( Triticum aestivum L.) genotypes at tillering stage  

Microsoft Academic Search

Drought is one of the major ecological factors limiting crop production and food quality globally, especially in the arid and semi-arid areas of the world. Wheat is the staple food for more than 35% of world population and wheat cultivation is mainly restricted to such zones with scarcity of water, so wheat anti-drought physiology study is of importance to wheat

Hong-Bo Shao; Li-Ye Chu; Gang Wu; Jin-Heng Zhang; Zhao-Hua Lu; Ya-Chen Hu

2007-01-01

214

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

Microsoft Academic Search

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

Aaron Kimple; William Schuster

215

Mortality and physiological stress of year-classes of landlocked and migratory Atlantic salmon, brown trout and brook trout in acidic aluminium-rich soft water  

Microsoft Academic Search

Physiological stress, measured as changes in plasma chloride, and mortality were measured on different year-classes of landlocked and migratory Atlantic salmon, two strains of brown trout, and brook trout, in a flow-through system with acidic Al-rich soft water. The oldest year-classes of salmon were smolts. Water from Lake Byglandsfjord (pH = 5.9), was enriched 1 th inorganic Al (as AlCl3)

B. O. Rosselind; O. K. Skogheim; F. Kroglund; E. Hoell

1986-01-01

216

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

Microsoft Academic Search

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

H. Arthur Woods; Jon F. Harrison

2001-01-01

217

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

2005-01-01

218

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.

0002-11-30

219

DEVELOPING JOINT PROBABILITY DISTRIBUTIONS OF SOIL WATER RETENTION CHARACTERISTICS  

EPA Science Inventory

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

220

WATER TEMPERATURE CHARACTERISTICS OF LAKES SUBJECTED TO CLIMATE CHANGE  

EPA Science Inventory

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

221

Combustion characteristics of heavy oil-water emulsions  

Microsoft Academic Search

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

Javier M. Ballester; Norberto Fueyo; César Dopazo

1996-01-01

222

Partitioning Characteristics of Perfluorooctane Sulfonate Between Water and Foods  

Microsoft Academic Search

As a persistent, bioaccumulative, and toxic organic pollutant, perfluorooctane sulfonate (PFOS) has been found ubiquitously\\u000a in the environment, including in tap water. For the first time, we studied PFOS sorption from water to foods (nine commonly\\u000a consumed vegetables, three meats, and cereals) at two temperatures to estimate the daily intake of PFOS attributable to cooking\\u000a and food preparation. The values

Feng Xiao; Matt F. Simcik; John S. Gulliver

223

Altered hMSC functional characteristics in short-term culture and when placed in low oxygen environments: implications for cell retention at physiologic sites.  

PubMed

Background: It is very difficult to conserve critical cell characteristics during expansion in culture, particularly those of adult mesenchymal stromal cells (MSCs), whose characteristics can change rapidly even within a short period of expansion. Aim: In this study our aim was to measure cell characteristics that are critical for retention at the injury site after therapeutic delivery. Cells were cultured under conditions typical of current standard best practice. The impact of passage number was assessed and assays were performed in low oxygen (2%) as an in vitro model of physiologic oxygen tension at injury sites. The effect of chemokine preconditioning with SDF1 was also assessed. Materials & methods: Bone marrow mononuclear cells from patients recruited to the REGENERATE Phase II clinical trials, along with MSCs from healthy volunteers subjected to a short period of expansion, were assessed for attachment and migration ability. Using MSCs from healthy donors, the effect of reduced oxygen was also assessed. Results: Short-term expansion resulted in increased cell attachment but decreased rate of migration, whereas attachment and migration of patient-derived bone marrow mononuclear cells was highly heterogeneous. Reduced oxygen impaired MSC attachment but not migration. Finally, SDF1 did not improve any of the responses. Conclusion: The basic functional responses of MSCs required for retention and engraftment alter rapidly even over a relatively short expansion period. This needs careful consideration when expanding cells to achieve clinical quantities for therapy. PMID:24750057

Bain, Owen; Detela, Giulia; Kim, Hae-Won; Mason, Chris; Mathur, Anthony; Wall, Ivan B

2014-03-01

224

Comparison of leaf saturation isothermal remanent magnetisation (SIRM) with anatomical, morphological and physiological tree leaf characteristics for assessing urban habitat quality.  

PubMed

Leaf saturation isothermal remanent magnetisation (SIRM) is known as a good proxy of atmospheric, traffic related particulate matter (PM) concentration. In this study, we compared leaf SIRM with Leaf area (LA), leaf dry weight (LDW), specific leaf area (SLA), stomatal density (SD), relative chlorophyll content (RCC), chlorophyll fluorescence parameters (Fv/Fm and PI) for three urban tree types in the city of Ghent, Belgium. A negative significant relationship of LA, LDW and Fv/Fm, and a positive significant relationship of SLA with leaf SIRM was observed. Among all considered parameters, leaf SIRM had the highest potential for discrimination between contrasting land use classes. It was concluded that urban habitat quality can be monitored with leaf SIRM, independent of the other above mentioned plant parameters. The anatomical, morphological and physiological tree leaf characteristics considered are not good indicators for atmospheric PM, but might be interesting bio-indicators of other air pollutants than PM. PMID:23266296

Kardel, Fatemeh; Wuyts, Karen; Khavaninzhadeh, Ali Reza; Wuytack, Tatiana; Babanezhad, Manoochehr; Samson, Roeland

2013-12-01

225

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

226

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

227

LabHorta: a controlled aquarium system for monitoring physiological characteristics of the hydrothermal vent mussel Bathymodiolus azoricus  

Microsoft Academic Search

LabHorta is a facility composed of laboratories and retrievable deep-sea\\u000a cages created to support and expand the capabilities of research\\u000a cruises. It also enhances the ability to conduct experimental studies\\u000a with organisms from deep-sea hydrothermal vents and other deep-sea\\u000a environments, while keeping them under controlled conditions of pressure\\u000a and water chemistry. This paper presents a case study with the vent

Ana Colaco; Raul Bettencourt; Valentina Costa; Silvia Lino; Humberto Lopes; Ines Martins; Luis Pires; Catarina Prieto; Ricardo Serrao Santos

2011-01-01

228

Acoustical characteristics of leak signals in plastic water distribution pipes  

Microsoft Academic Search

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

Osama Hunaidi; Wing T. Chu

1999-01-01

229

Characteristics of pipe system failures in light water reactors  

Microsoft Academic Search

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

S. L. Basin; E. T. Burns

1977-01-01

230

Release of glycosaminoglycans in physiological saline and water by wet-spun chitin--acid glycosaminoglycan fibers.  

PubMed

The present study sought to prepare novel chitin- acid glycosaminoglycan fibers that released a portion of the glycosaminoglycans in animal body fluids for use as novel biocompatible dressing materials (artificial skin) in the veterinary and clinical fields. A clear solution of sodium N-acetylchitosan salt (alkaline chitin) mixed with sodium hyaluronate, sodium heparin, sodium chondroitin 4-sulfate, sodium chondroitin 6-sulfate, or sodium dermatan sulfate in 14% aqueous NaOH was spun through a viscose-type spinneret into a 10% aqueous H(2)SO(4) solution saturated with (NH(4))(2)SO(4) at room temperature. The result was chitin fibers containing 5--33% glycosaminoglycans. In a dry state these fibers were white and had a soft feel but they were mechanically weak (0.31--0.69 g/denier tenacity and 3.1--10.6% elongation). Portions (85--97%) of the glycosaminoglycans were released from the fibers by soaking them in physiological saline or distilled water. Scanning electron microscopy analyses revealed a smooth striped surface on the original filaments, and a scaly surface appeared on the chitin filament after soaking. PMID:11400133

Hirano, S; Zhang, M; Nakagawa, M

2001-09-15

231

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

PubMed Central

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.

Aarts, Mark G. M.

2014-01-01

232

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

PubMed

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

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

2014-02-01

233

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

PubMed

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

2013-02-01

234

Characteristics of thermal conductivity in classical water models  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

235

Water relation characteristics of Alhagi sparsifolia and consequences for a sustainable management  

Microsoft Academic Search

Water relation characteristics of the desert legumeAlhagi sparsifolia were investigated during the vegetation period from April to September 1999 in the foreland of Qira oasis at the southern\\u000a fringe of the Taklamakan Desert, Xinjiang Uygur Autonomous Region of China. The seasonal variation of predawn water potentials\\u000a and of diurnal water potential indicated thatAlhagi plants were well water supplied over the

Fanjiang Zeng; Ximing Zhang; A. Foetzki; Xiangyi Li; Xiaoming Li; M. Runge

2002-01-01

236

Genotypic differences in physiological characteristics in the tolerance to drought and salinity combined stress between Tibetan wild and cultivated barley.  

PubMed

Greenhouse pot experiments were conducted to investigate genotypic differences in response to individual and combined stresses of drought and salinity between Tibetan wild barley genotypes (XZ5, drought-tolerant; XZ16, salinity/aluminum tolerant) and cv. CM72 (salinity-tolerant). Either drought (D) or salinity (S) alone and in combination (D + S) stresses significantly decreased plant growth, chlorophyll content, net photosynthetic rate (Pn), maximal photochemical efficiency of PSII (Fv/Fm), water potential and osmotic potential, with the largest suppression under combined stress, and two wild genotypes showing more tolerance than CM72. Water use efficiency (WUE) increased significantly in XZ5 and XZ16 after D + S, but no significant change in CM72. XZ5 and XZ16 showed 30.9% and 12.1% higher K(+) level and 30.5% and 24.1% lower Na(+)/K(+) ratio in plants, compared with CM72, with increased metal nutrients as Ca, Fe and Mn under D + S. The peak accumulation in proline and glycine-beatine was recorded in combined stress with larger accumulation in two wild genotypes. Moreover, larger increases in the level of ASA and GSH, and the activities of Ca(2+)Mg(2+)-ATPase, and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), guaiacol peroxidase (POD) and glutathione reductase (GR) under D + S vs control were observed in XZ5 and XZ16 than CM72, with less accumulation of H(2)O(2) and malondialdehyde. These results suggest that high tolerance to D + S stress of XZ5 and XZ16 is closely related to lower Na(+)/K(+) ratio and enhanced Ca(2+)Mg(2+)-ATPase, proline, glycine-beatine and WUE, and improved capacity of antioxidative performance to scavenge reactive oxygen species and thus suppressed level of lipid peroxidation. PMID:23232247

Ahmed, Imrul Mosaddek; Dai, Huaxin; Zheng, Weite; Cao, Fangbin; Zhang, Guoping; Sun, Dongfa; Wu, Feibo

2013-02-01

237

[The medium chain fat acids. Content in food. Physiology, characteristics of metabolism and application in clinical practice].  

PubMed

It is rational, according to biology laws and purposes for which cells use fatty acids, to distinguish between saturated (without double bonds in chain), monoene (with one bond), unsaturated (with 2 and 3 double bonds) and polyene (with 4, 5 and 6 double bonds) acids. The saturated and monoene fatty acids are mainly the substratum for oxygenation and working out of energy by cells. The unsaturated fatty acids are the substratum for formation of membranes. The polyene fatty acids are the predecessors of synthesis of eicosanoids and aminophosphotides. With subject to characteristics of metabolism and transfer in vivo, the fatty acids are subdivided into short chain C4 - C8 and medium chain C-10 - C-14 fatty acids. The etherification occurs with glycerin into "short" triglycerides which are not bounded with apoproteins. The long chain fatty acids form "long" triglycerides which in enterocytes are structured by apoprotein B-48 into composition of chylomicrons. It is possible to validly consider that difference in outflow from enterocytes to veins of portal system (which includes veins of omentum) of medium chain fatty acids in the form of short triglycerides can directly input into pathogenesis of syndrome of isolated omental obesity and metabolic syndrome. The another input into the mentioned conditions is the secretion through ductus thoracicus into large veins of greater systemic circulation of long chain fatty acids in the form of triglycerides in the content of chylomicrons. The omental obesity is the only specific symptom of metabolic syndrome. PMID:24340938

Arkhipovski?, A V; Titov, V N

2013-06-01

238

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

EPA Science Inventory

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

239

Settling characteristics of problem algae in the water treatment process.  

PubMed

The settling velocity or removal rates of problem algae in the water treatment process and their flocculants were measured with settling column (SETCOL) and fluorometric method. Our research who were centred on the algal density and shape affecting the settling. The settling velocities of large algae ranged from 0.1 cm/h to 2.6 cm/h, whereas those of small algae were below 1.0 cm/h. The settlings of algae in the stationary growth phase significantly increased and dead algae corresponded with the declining algae. The extent of deformation, which was expressed as the coefficient of form resistance of the algae had the great influences upon the settling. The most extreme deformed algae were needle-shaped ones like Synedra acus, which was known to be a problem in water treatment processes in Korea. Changes in the settling velocity of algae were correlated with algal volume and morphology rather than cell density. PMID:16752771

Choi, S K; Lee, J Y; Kwon, D Y; Cho, K J

2006-01-01

240

Characteristics of hydrogen nanobubbles in solutions obtained with water electrolysis  

Microsoft Academic Search

A solution supersaturated with hydrogen obtained by water electrolysis was studied using cyclic voltammetry. The cyclic voltammogram of the solution supersaturated with hydrogen gave a peak current at ?0.1V vs. Ag?AgCl. No peak current in a solution saturated with hydrogen was observed by bubbling hydrogen gas through the solution. The peak current was influenced by the temperature and ion type

Kenji Kikuchi; Shoichi Nagata; Yoshinori Tanaka; Yasuhiro Saihara; Zempachi Ogumi

2007-01-01

241

Developing joint probability distributions of soil water retention characteristics  

Microsoft Academic Search

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

Robert F. Carsel; Rudolph S. Parrish

1988-01-01

242

Fouling characteristics of cooling tower water containing corrosion inhibitors  

Microsoft Academic Search

Corrosion inhibitors investigated included zinc-chromate and phosphates. In addition, additives including polyacrylate and phosphonate (HEDP and AMP) were used to determine their effectiveness as antifoulants. The tests were conducted in a simulated cooling tower water system. The parameters investigated were: test section surface temperature 130, 145 and 160°F, velocity in test section 3.0, 5.5 and 8.5 ft\\/sec, pH 6.0 -8.0,

Santoso

1987-01-01

243

Characteristics of electrolyzed anode water as a display cleaning medium  

Microsoft Academic Search

RCA cleaning has been intensively studied, and during the last ten years has been modified to meet high integration and environmental\\u000a requirements. Ozonized, hydrogenised, or electrolyzed water cleaning technologies are being developed in order to fulfil these\\u000a requirements. However, to date, the proposed approaches have not broken through the RCA paradigm such as SC1 and SC2 steps.\\u000a In this work,

Kunkul Ryoo

2005-01-01

244

The emission characteristics of low-pressure water vapor discharge UV emitters  

Microsoft Academic Search

We have studied the characteristics of UV emission sources operating on low-pressure normal (H2O) and heavy (D2O) water vapor excited by periodic-pulsed and glow discharges. The emission in a 300–330 nm wavelength interval has been studied\\u000a in detail for water vapor pressures ranging from 50 to 2500 Pa. A comparison of the characteristics of emission from discharge\\u000a plasma at low

A. K. Shuaibov; A. A. General; V. A. Kel’man; I. V. Shevera

2008-01-01

245

The emission characteristics of low-pressure water vapor discharge UV emitters  

Microsoft Academic Search

We have studied the characteristics of UV emission sources operating on low-pressure normal (H2O) and heavy (D2O) water vapor excited by periodic-pulsed and glow discharges. The emission in a 300 330 nm wavelength interval has been studied in detail for water vapor pressures ranging from 50 to 2500 Pa. A comparison of the characteristics of emission from discharge plasma at

A. K. Shuaibov; A. A. General; V. A. Kel'Man; I. V. Shevera

2008-01-01

246

Adsorption characteristics of water vapor on honeycomb adsorbents  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

247

Spatial, Spectral, and Temporal Characteristics of Stimulated Light Scattering in Water  

Microsoft Academic Search

Spatial, temporal, and spectral characteristics of stimulated light scattering (SS) in water were investigated in both nano- and picosecond ranges under different experimental conditions and compared with the analogous characteristics of stimulated light scattering in other liquids. Stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) of light were studied. The results obtained provide useful information on the structure of

A. D. Kudryavtseva; N. V. Tcherniega

2002-01-01

248

Water quality of the Anabar River indicated by phytoplankton structure and hydrochemical characteristics  

Microsoft Academic Search

This is the first study of phytoplankton structure and physicochemical characteristics of the full length of the Anabar River—a\\u000a large river in the Arctic basin. The study has revealed characteristics of phytoplankton assemblages and hydrochemistry of\\u000a the reaches of the river. Water quality was found to decrease where mineral resources industry operates. The data on phytoplankton\\u000a structure and physicochemical characteristics

V. A. Gabyshev; O. I. Gabysheva

2010-01-01

249

Tropine forming tropinone reductase gene from Withania somnifera (Ashwagandha): biochemical characteristics of the recombinant enzyme and novel physiological overtones of tissue-wide gene expression patterns.  

PubMed

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

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

2013-01-01

250

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

Microsoft Academic Search

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

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

251

Water removal characteristics of proton exchange membrane fuel cells using a dry gas purging method  

Microsoft Academic Search

Water removal from proton exchange membrane fuel cells (PEMFC) is of great importance to improve start-up ability and mitigate cell degradation when the fuel cell operates at subfreezing temperatures. In this study, we report water removal characteristics under various shut down conditions including a dry gas-purging step. In order to estimate the dehydration level of the electrolyte membrane, the high

Sang-Yeop Lee; Sang-Uk Kim; Hyoung-Juhn Kim; Jong Hyun Jang; In-Hwan Oh; Eun Ae Cho; Seong-Ahn Hong; Jaejun Ko; Tae-Won Lim; Kwan-Young Lee; Tae-Hoon Lim

2008-01-01

252

Behavioral and biochemical characteristics of rats preferring ethanol or water  

SciTech Connect

Considering that learning and memory processes are largely determined by the intensity of RNA synthesis in specific brain structure, the authors study the relationship between learning ability of rats preferring ethanol or water and the level of RNA-synthesizing activity of brain cell nuclei. RNA-synthesizing activity of cell nuclei from cortical gray matter of the animals was determined one month after selection by measuring incorporation of deuterium-uridine triphosphate. The numerical results were subjected to statistical analysis by Student's test at P 0.05. It is shown that the altered behavior of animals preferring ethanol is evidently based on disturbed interaction between mediator and genetic structures of brain cells.

Kulikova, O.G.; Borodkin, Y.S.; Razumovskaya, N.I.; Shabanov, P.D.; Sokolovskaya, N.E.

1985-05-01

253

Explosion characteristics of intense femtosecond-laser-driven water droplets  

SciTech Connect

An efficient acceleration of energetic ions is observed when small heavy-water droplets of {approx}20 {mu}m diameter are exposed to ultrafast ({approx}40 fs) Ti:sapphire laser pulses of up to 10{sup 19} W/cm{sup 2} intensity. Quantitative measurements of deuteron and neutron spectra were done, allowing one to analyze the outward and inward directed deuteron acceleration from the droplet. Neutron spectroscopy based on the D(d,n) fusion reaction was accomplished in four different spatial directions. The energy shifts of those fusion neutrons produced inside the exploding droplet reflect a remaining deuteron acceleration inside the irradiated droplet along the axis of the incident laser beam. The overall neutron yield of the microdroplets is relatively small as a result of the dominant outward directed acceleration of the deuterons with 1200 neutrons/shot. Relying on the 'explosionlike' acceleration of such spherical droplet targets we have developed a spray target consisting of heavy-water microspheres with diameters of 150 nm. Both the high deuteron energies of up to 1 MeV resulting from the irradiation intensity of {approx}10{sup 19} W/cm{sup 2} as well as the collisions between the deuterons and the surrounding spray delivered about one order of magnitude more neutrons than the single-droplet system. The {approx}6x10{sup 3} neutrons per laser pulse from the spray can be attributed to an efficient deuteron release from a significantly smaller laser excited volume as from deuterium-cluster targets.

Schnuerer, M.; Ter-Avetisyan, S.; Busch, S.; Kalachnikov, M.; Stiel, H.; Nickles, P.V.; Sandner, W. [Max-Born-Institut, Max-Born-Strasse 2a, D-12489 Berlin (Germany); Hilscher, D.; Jahnke, U. [Hahn-Meitner-Institut, Glienickerstrasse 100, D-14109 Berlin (Germany)

2004-11-01

254

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

2007-01-01

255

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

PubMed

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

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

2013-01-01

256

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

USGS Publications Warehouse

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

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

1999-01-01

257

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.

1976-01-01

258

Physiological response, time-motion characteristics, and reproducibility of various speed-endurance drills in elite youth soccer players: small-sided games versus generic running.  

PubMed

Purpose: To quantify the physiological responses, time-motion characteristics, and reproducibility of various speed-endurance-production (SEP) and speed-endurance-maintenance (SEM) drills. Methods: Sixteen elite male youth soccer players completed 4 drills: SEP 1 v 1 small-sided game (SSG), SEP running drill, SEM 2 v 2 SSG, and SEM running drill. Heart-rate response, blood lactate concentration, subjective rating of perceived exertion (RPE), and time-motion characteristics were recorded for each drill. Results: The SEP and SEM running drills elicited greater (P < .05) heart-rate responses, blood lactate concentrations, and RPE than the respective SSGs (ES 1.1-1.4 and 1.0-3.2). Players covered less (P < .01) total distance and high-intensity distance in the SEP and SEM SSGs than in the respective running drills (ES 6.0-22.1 and 3.0-18.4). Greater distances (P < .01) were covered in high to maximum acceleration/deceleration bands during the SEP and SEM SSGs than the respective running drills (ES 2.6-4.6 and 2.3-4.8). The SEP SSG and generic running protocols produced greater (P < .05) blood lactate concentrations than the respective SEM protocols (ES 1.2-1.7). Small to moderate test-retest variability was observed for heart-rate response (CV 0.9-1.9%), RPE (CV 2.9-5.7%), and blood lactate concentration (CV 9.9-14.4%); moderate to large test-retest variability was observed for high-intensity-running parameters (CV > 11.3%) and the majority of accelerations/deceleration distances (CV > 9.8%) for each drill. Conclusions: The data demonstrate the potential to tax the anaerobic energy system to different extents using speed-endurance SSGs and that SSGs elicit greater acceleration/deceleration load than generic running drills. PMID:24755972

Ade, Jack D; Harley, Jamie A; Bradley, Paul S

2014-05-01

259

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

PubMed

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

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

2013-12-01

260

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

261

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

PubMed

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

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

2006-05-01

262

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

PubMed

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

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

2012-10-15

263

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

2006-01-01

264

Rowing Physiology.  

ERIC Educational Resources Information Center

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

Spinks, W. L.

265

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

NASA Astrophysics Data System (ADS)

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

Li, Hongshou; Wang, Wanfu; Liu, Benli

2014-06-01

266

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

Microsoft Academic Search

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

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

2011-01-01

267

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

SciTech Connect

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

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

1989-06-01

268

Simulation investigation on fluid characteristics of jet pipe water hydraulic servo valve based on CFD  

Microsoft Academic Search

Simulation investigation on fluid characteristics of the water hydraulic jet pipe servo valve (WHJPSV) is conducted through\\u000a a commercial computational fluid dynamics (CFD) software package FLUENT. In particular, the factors to fluid characteristics\\u000a of WHJPSV are addressed, which include diameter combination of jet pipe and receiver pipe, jet pipe nozzle clearance, angle\\u000a between two jet receiver pipes and deflection angle

Ru-ping Li; Song-lin Nie; Meng-lin Yi; Jun Ruan

2011-01-01

269

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

Microsoft Academic Search

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

Daniel Ballesteros; Christina Walters

2007-01-01

270

The emission characteristics of low-pressure water vapor discharge UV emitters  

NASA Astrophysics Data System (ADS)

We have studied the characteristics of UV emission sources operating on low-pressure normal (H2O) and heavy (D2O) water vapor excited by periodic-pulsed and glow discharges. The emission in a 300 330 nm wavelength interval has been studied in detail for water vapor pressures ranging from 50 to 2500 Pa. A comparison of the characteristics of emission from discharge plasma at low (50 150 Pa) and elevated (2.0 2.5 kPa) water vapor pressures reveals significant differences in the character of emission spectra, which can be related to the different types of emitting species (hydroxy radicals versus small clusters of such radicals and water molecules). Discharge current and emission intensity pulses in the periodic-pulsed discharge regime have been measured.

Shuaibov, A. K.; General, A. A.; Kel'Man, V. A.; Shevera, I. V.

2008-07-01

271

Mapping QTLs for seedling characteristics under different water supply conditions in rice (Oryza sativa).  

PubMed

A greater understanding of the genetics of responses to water deficit/drought may be helpful in improving water-deficit resistance in the early stages of growth in rice. A recombinant inbred population derived from a cross between Zhenshan 97 and Minghui 63 was grown in hydroponic culture to characterize the responses of seedlings to water deficit imposed by PEG 6000 and to identify quantitative trait loci (QTLs) for seedling characteristics under both well-watered and water-deficit conditions. Generally, the two parents showed significant differences in plant height (PH), maximum root length (MRL), shoot fresh weight (SFW), root fresh weight (RFW), number of roots and root:shoot ratio based on fresh weight under both well-watered and water-deficit conditions. For two parents, PH and SFW were significantly inhibited under water deficit. However, the other four traits had larger values under water deficit. Among 26 and 34 QTLs detected for the six traits studied under the well-watered and water-deficit conditions, respectively, a total of 14 QTLs for SFW, PH, RFW and MRL (23% of total QTLs detected) were detected in similar or tight linkage regions in both conditions. Among 11 intervals on 7 chromosomes identified to harbor multiple QTLs, 8 intervals were found to affect related traits under the two water supply conditions and 3 intervals were observed to be water supply-specific regions and had effects only under well-watered conditions, suggesting that water supply-specific regions or QTLs may be closely associated with the responses of lines to water deficit in the study. Several regions for the traits studied were also found to affect the root-related traits in previous studies and might be used in marker-assisted selection for drought-resistant rice in breeding programs. PMID:18251870

Cui, Kehui; Huang, Jianliang; Xing, Yongzhong; Yu, Sibin; Xu, Caiguo; Peng, Shaobing

2008-01-01

272

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

PubMed

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

Ou, Yang; Wang, Xiaoyan

2011-01-01

273

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

USGS Publications Warehouse

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

Cummings, T. Ray

1980-01-01

274

Statistical assessment of soil-water characteristic curve models for geotechnical engineering  

Microsoft Academic Search

A number of empirical equations have been proposed for the soil-water characteristic curve. A nonlinear, least squares method was used to determine best-fit parameters for several empirical equations that were best-fit to 230 water content versus soil suction data sets. In addition, two proposed correction methods to accommodate high soil suctions up to 1 000 000 kPa were applied to

W. Scott Sillers; Delwyn G. Fredlund

2001-01-01

275

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

Microsoft Academic Search

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

Jose A. Marengo

2005-01-01

276

Numerical study on heat transfer and resistance characteristics of supercritical water inside internally-ribbed tube  

NASA Astrophysics Data System (ADS)

The effects of structural parameters for internally-ribbed tube on heat transfer and flow characteristics of supercritical water were studied numerically. The results show that the heat transfer and pressure loss increases with the increase of mass flow or heat flux. The Heat transfer and resistance coefficients of supercritical water increase with the spiral rising angle decrease or rib height increase, while rib width has a weak influence on heat transfer and pressure drop.

Zhao, Zhenxing; Wang, Xiangyu; Che, Defu

2014-04-01

277

FRICTION CHARACTERISTICS OF WATER, R-134a, AND AIR IN SMALL TUBES  

Microsoft Academic Search

This manuscript provides a systematic test of friction characteristic for air, water, and liquid refrigerant R-134a in 10 tubes with inside diameters from 0.173 to 4.01 mm. The test results show that the conventional minor losses correlations for large tubes may be adequately used to estimate the related inlet, exit and acceleration components for water, refrigerant, and low-speed air flow

Chien-Yuh Yang

2003-01-01

278

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

2014-08-01

279

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.

2014-01-01

280

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

Microsoft Academic Search

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

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

2002-01-01

281

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

NASA Technical Reports Server (NTRS)

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

Evans, D. G.

1973-01-01

282

Parametric Study on Thermal-Hydraulic Characteristics of High Conversion Light Water Reactor.  

National Technical Information Service (NTIS)

To assess the feasibility of high conversion light water reactors (HCLWRs) from the thermal-hydraulic viewpoint, parametric study on thermal-hydraulic characteristics of HCLWR has been carried out by using a unit cell model. It is assumed that a HCLWR cor...

T. Mori M. Nakagawa S. Fujii

1988-01-01

283

Thermal-Hydraulic Characteristics of Double Flat Core HCLWR (High Conversion Light Water Reactor).  

National Technical Information Service (NTIS)

A thermal-hydraulic characteristics of double flat core high conversion light water reactor (HCLWR) is described. The concept of flat core proposed by Ishiguro et al. is to achieve negative void reactivity coefficient in tight lattice core, and at the sam...

J. Sugimoto T. Iwamura T. Okubo Y. Murao

1989-01-01

284

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

Microsoft Academic Search

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

Li Mo; Xia Huanga

2003-01-01

285

Characteristics of contaminants in water and sediment of a constructed wetland treating piggery wastewater effluent  

Microsoft Academic Search

Constructed wetland (CW) is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary effluent of livestock wastewater treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil layer and to

Soyoung Lee; Marla C. Maniquiz; Lee-Hyung Kim

2010-01-01

286

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

EPA Science Inventory

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

287

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

Microsoft Academic Search

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

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

2005-01-01

288

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

Microsoft Academic Search

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

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

2006-01-01

289

The Characteristics Improvement of Ozone Water Production by Multi-layer Electrodes at Water Electrolysis Cell by Solid Polymer Electrolyte  

NASA Astrophysics Data System (ADS)

Ozone is recently used for many purposes as an environmental friendly oxidant, so the ozone production device with high ozone concentration and low production energy is desired. One of the candidates for such device is the ozone water production by water electrolysis cell using the solid polymer electrolyte with PbO2 anode catalyst, which has merits to be compact and to produce high-concentration ozone water directly by the deionized water electrolysis. In this study, we have tested ozone water production by changing electrodes and electrolytes constitution in order to improve the ozone production performance. Tested two electrolytes are Nafion117 and a membrane-electrode assembly (MEA) with Pt catalyst on cathode side of Nafion117. Tested two electrodes are mono-layer of Ti expanded metal and four different mesh layers of Ti expanded metal. Ozone water production tests are performed under long-term operations changing temperature and flow rate to optimize experimental conditions. The voltage-current characteristic for electrolysis cell have been improved significantly, when the electrode is four layers of Ti metal and the electrolyte is the MEA with Pt catalyst. The stable ozone water concentration has been obtained by operating the cell for about 8 hours. The optimum temperature and water flow rate for ozone water production are 25˜30° and 33L/h, respectively. Furthermore, the optimum overpotential was measured by a reference electrode at the cathode-side MEA, and the anode catalyst suitable for ozone water production was identified to be ?PbO2 by the X ray diffraction pattern.

Ohba, Takahiro; Kusunoki, Hironobu; Sunakawa, Daisuke; Araki, Takuto; Onda, Kazuo

290

Rhizosphere water dynamics: role of exudates in mediating water retention and flow characteristics  

NASA Astrophysics Data System (ADS)

In recent years, significant amount of literature showed that rhizosphere's physical and chemical properties markedly differ from those of the bulk soil. Plants invest large portion of their photosynthetic carbon in developing root architecture that optimally exploits water and nutrient distributions in the soil. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we investigated the role of root exudates on rhizosphere water dynamics using analog system. Glass beads were used to represent loose soil and dilute solutions of polygalacutronic acid (PGA) to mimic exudates (0, 1, 5, 15 and 29 g/L). The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. On the other hand, sand samples were saturated with PGA at the same concentration used to study the effect of exudates on water evaporation rate. The effect of root exudates on soil water retention can be attributed to at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent with visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly limited to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in <- 1 bar suction. At the same time, the osmotic potential results from these organic exudates play an important role in reducing the evaporation rate. These results will provide direct quantitative evidence of how rhizosphere organic matter helps plant-soil relations.

Albalasmeh, Ammar; Ghezzehei, Teamrat

2013-04-01

291

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

USGS Publications Warehouse

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

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

2004-01-01

292

Physiological, anatomical and leaf hydraulic effects on leaf water delta18O enrichment in different plant species  

Microsoft Academic Search

Stable oxygen isotope ratios (delta18O) of plant and source waters are valuable tools in the analysis of water and carbon fluxes at leaf, plant, and ecosystem scales. Recent improvements in mechanistic models have significantly advanced the understanding of isotopic leaf water enrichment, which is an important source of delta18O variability in plants and ecosystems. However, the marked variability in leaf

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

2007-01-01

293

Comparison of selected cultural, physical, and water-quality characteristics of lakes in Washington  

USGS Publications Warehouse

The report presents comparisons and a graphical overview of the relative magnitude and regional and statewide distribution of 19 selected cultural, physical, and water-quality characteristics measured in a reconnaissance study of several hundred lakes in Washington. Statewide, mean depth of almost one-fourth of the lakes is shallow (2.0 meters or less), and only 7 percent of the lakes have mean depths greater than 20 meters. About one-third of the lakes had Secchi-disc readings of 2.0 meters or less, a value often considered characteristic of eutrophic lakes. The poorest water clarity was observed in the Columbia Plateau, where 68 percent of the lakes had Secchi-disc readings of less than 2.0 meters. More than one-third of the lakes in the State had total phosphorus concentrations that exceeded 30 micrograms per liter, a concentration that is often considered characteristic of eutrophic lakes. (Woodard-USGS)

Bortleson, Gilbert Carl; Dion, N. P.

1979-01-01

294

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

USGS Publications Warehouse

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

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

2000-01-01

295

[Effects of irrigation and planting pattern on winter wheat water consumption characteristics and dry matter production].  

PubMed

Taking high-yield winter wheat cultivar 'Jimai 22' as test material, a field experiment was conducted in 2008-2010 to study the effects of different irrigation and planting modes on the water consumption characteristics and dry matter accumulation and distribution of winter wheat. Three planting patterns (uniform row, wide-narrow row, and furrow) and four irrigation schedules (no irrigation, W0; irrigation at jointing stage, W1; irrigation at jointing and anthesis stages, W2; and irrigation at jointing, anthesis, and milking stages, W3; with 60 mm per irrigation) were installed. With increasing amount of irrigation, the total water consumption and the ratio of irrigation water to total water consumption under different planting patterns all increased, while the soil water consumption and its ratio to total water consumption decreased significantly. As compared with W0, the other three irrigation schedules had a higher dry matter accumulation after anthesis and a higher grain yield, but a lower water use efficiency (WUE). Under the same irrigation schedules, furrow pattern had higher water consumption ratio, grain yield, and WUE. Taking the grain yield and WUE into consideration, furrow pattern combined with irrigation at jointing and anthesis stages would be the optimal water-saving and planting modes for the winter wheat production in North China Plain. PMID:24175516

Dong, Hao; Chen, Yu-Hai; Zhou, Xun-Bo

2013-07-01

296

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

2006-09-01

297

The relationship between phytoplankton distribution and water column characteristics in North West European shelf sea waters.  

PubMed

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

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

2012-01-01

298

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

Microsoft Academic Search

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

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

2004-01-01

299

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.

2013-12-01

300

Regulatory Physiology  

NASA Technical Reports Server (NTRS)

As noted elsewhere in this report, a central goal of the Extended Duration Orbiter Medical Project (EDOMP) was to ensure that cardiovascular and muscle function were adequate to perform an emergency egress after 16 days of spaceflight. The goals of the Regulatory Physiology component of the EDOMP were to identify and subsequently ameliorate those biochemical and nutritional factors that deplete physiological reserves or increase risk for disease, and to facilitate the development of effective muscle, exercise, and cardiovascular countermeasures. The component investigations designed to meet these goals focused on biochemical and physiological aspects of nutrition and metabolism, the risk of renal (kidney) stone formation, gastrointestinal function, and sleep in space. Investigations involved both ground-based protocols to validate proposed methods and flight studies to test those methods. Two hardware tests were also completed.

Lane, Helen W.; Whitson, Peggy A.; Putcha, Lakshmi; Baker, Ellen; Smith, Scott M.; Stewart, Karen; Gretebeck, Randall; Nimmagudda, R. R.; Schoeller, Dale A.; Davis-Street, Janis

1999-01-01

301

Water characteristics associated with the occurrence of Legionella pneumophila in dental units.  

PubMed

This study evaluated the incidence of Legionella pneumophila in dental unit water samples and investigated how the occurrence of these bacteria may be related to some physical, chemical and bacteriological characteristics of the water. The samples were taken from the incoming tap water, oral rinsing cup, air-water syringe, ultrasonic scaler, and the turbine of 23 dental units of private and public institutions. Apart from L. pneumophila (serogroup 1 and 3) isolated in 22 out of the 101 (21.8%) water samples tested, two other species were found: L. bozemanii and L. dumoffii. The highest densities and frequency of L. pneumophila were observed in the water coming into the units and in the dental units of public institutions. A negative association between L. pneumophila and 36 degrees C and 22 degrees C heterotrophic total plate counts and other gram-negative bacteria was found. An inverse association between the concentration of L. pneumophila and water temperature was also observed. The values of pH and total hardness did not show any significant difference in the L. pneumophila-positive and -negative dental unit waters. Finally, the chemical oxygen demand (COD) and residual chlorine were found to correlate positively with L. pneumophila. PMID:10706473

Zanetti, F; Stampi, S; De Luca, G; Fateh-Moghadam, P; Antonietta, M; Sabattini, B; Checchi, L

2000-02-01

302

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 resource conflicts among different sectors. In this research, the VWC of rice, a major crop in China, is taken as the research object. China covers a vast land area, and the VWC of rice varies widely between different regions. The VWC of rice in China is assessed and the spatial characteristics are also analysed. The total VWC is the total volume of freshwater both consumed and affected by pollution during the crop production process, including both direct and indirect water use. Prior calculation frameworks of the VWC of crops did not contain all of the virtual water content of crops. 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 an input-output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were found to be 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a roughly three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water usage were mainly concentrated in Southeast and Southwest China, while the 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.

2014-06-01

303

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

NASA Astrophysics Data System (ADS)

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

Casper, A. F.

2005-05-01

304

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

Microsoft Academic Search

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

Valter Tucci; Andrea Hardy; Patrick M. Nolan

2006-01-01

305

PHYSIOLOGICAL RESPONSES AND LIFERAFT MICROCLIMATES DURING A FOUR DAY SURVIVAL TRIAL IN 20MAN CANOPIED RAFTS IN TROPICAL WATERS  

Microsoft Academic Search

To survive when water is scarce one must excrete as little water as possible, and above all one must not sweat. Liferaft survivors seek to achieve these aims by eating a ration that minimises the solutes to be excreted in the urine, and by using inflatable rafts that have a double-skinned canopy to shade them from the sun. This paper

G M Budd

306

[Functional characteristics of bacterioplankton with reference to its aggregation in water bodies of different types].  

PubMed

The functional characteristics of bacterioplankton have been studied with reference to its aggregation in water bodies of different types. Several methods were used for calculation of the total numbers of bacteria and proportion of aggregated cells. Analysis of the experimental data has shown a relationship between the functional characteristics of bacterioplankton, such as bacterial production, destruction of organic matter, and energy coefficient, and the proportion of aggregated bacteria. It has been shown that as this proportion increases, the production per cell and energy coefficients also increase. PMID:12400376

Shchur, L A; Aponasenko, A D; Lopatin, V N; Makarskaia, G V

2002-01-01

307

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

PubMed

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

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

2013-07-01

308

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

PubMed

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

Kerkhof, L; Santoro, M; Garland, J

2000-03-01

309

Water-quality characteristics of Everglades National Park, 1959-77, with reference to the effects of water management  

USGS Publications Warehouse

The U.S. Geological Survey has collected water-quality data in the Everglades National Park since 1959. Major ions, macronutrients, trace elements, and pesticides are the primary chemical groups analyzed. The period of record and frequency of sampling vary for each chemical group, with the longest record for the major ions and the shortest for the macronutrients. Within the park there are three major drainageways: Big Cypress Swamp, Shark River Slough, and Taylor Slough. Each drainageway exhibits unique hydrologic conditions, yet there is a high degree of homogeneity in water-quality characteristics among these areas. Seasonal changes in major-ion, trace-element, and macronutrient concentrations are marked in the shallow marsh. Concentrations generally increase in the dry season due to evapotranspiration, changes in chemical equilibria, and precipitation. Water-management practices in south Florida have changed the water quality in the Shark River Slough. Most major-ion, dissolved-solid, and iron concentrations and color levels have steadily increased since 1963. The water quality in the other two drainageways has not changed since sampling began. Chlorinated-hydrocarbon insecticide residues in bottom material were found in low concentration at every sampling station in the park. (USGS)

Waller, Bradley G.

1982-01-01

310

Effect of Ionic Soil Stabilizers on Soil-Water Characteristic of Special Clay  

NASA Astrophysics Data System (ADS)

The engineering properties of special clay are conventionally improved through the use of chemical additive such as ionic soil stabilizer (ISS). Such special clays are often referred to as stabilized or treated clays. The soil-water characteristic curves (SWCC) of special clays from Henan province and Hubei province were measured both in natural and stabilized conditions using the pressure plate apparatus in the suction range of 0-500 kPa. The SWCC results are used to interpret the special clays behavior due to stabilizer treatment. In addition, relationships were developed between the basic clay and stabilized properties such as specific surface area and pore size distribution. The analysis showed that specific surface area decreases, cumulative pore volume and average pore size diameter decrease, dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. The research data and interpretation analysis presented here can be extended to understand the water film change behaviors influencing the mechanical and physical properties of stabilized special clay soils. KEY WORDS: ionic soil stabilizer, special clay, pore size diameter, specific surface area, soil water characteristic curve, water film

Cui, D.; Xiang, W.

2011-12-01

311

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

PubMed

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

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

2004-01-01

312

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.

2000-01-01

313

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

2000-01-01

314

Water Vopar Desorption Characteristics of Powder Type Organic Sorbent in an Air Fluidized Bed  

NASA Astrophysics Data System (ADS)

This paper has dealt with water vapor desorption characteristics of powder type organic sorbent in an air fluidized bed. The Powder type organic sorbent was fluidized in a rectangular vessel by a humid air flow. The desorption rate of vapor and the variation in temperature in the sorbent bed were measured under various air temperature and humidity conditions. It was found that the air pressure loss of the fluidized sorbent layer increased with in an increase in water vapor concentration. Finally Sherwood number for mass transfer was correlated by means of Reynolds number,modified Stefan number. The ratio of sorbent particle diameter to the fluidized bed height and Schmidt number.

Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kameda, Kiyohiro; Okamoto, Tamio

315

Water Vapor Desorption Characteristics of Honeycomb Type Sorption Element Composed of Organic Sorbent  

NASA Astrophysics Data System (ADS)

This paper describes the water vapor desorption characteristics of honeycomb shape type sorbent element containing new organic sorbent of the bridged complex of sodium polyacrylate. The transient experiments in which the dry air was passed into the honeycomb type sorbent element sorbed water vapor were carried out under various conditions of air velocity, temperature, relative humidity and honeycomb length. The obtained data for desorption process were compared with those for sorption process. Finally, Sherwood number of mass transfer of the organic sorbent for desorption process was derived in terms of Reynolds number, modified Stefan number and non-dimensional honeycomb length.

Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kaneda, Makoto; Okamoto, Tamio; Seo, Jeong-Kyun

316

An experimental investigation of the burning characteristics of water-oil emulsions  

SciTech Connect

An experimental investigation was conducted on the combustion characteristics of droplets of n-heptane, n-decane, n-dodecane, n-hexadecane and iso-octane emulsified with various amount of water and freely falling in a furnace of controlled temperature. Results demonstrate the intricate influences of water emulsification on the ignition, extinction and micro-explosion of the droplet response, and that the droplet burning time can be significantly reduced through judicious fuel blending so as to minimize the ignition delay and advance the onset of micro-explosion.

Wang, C.H.; Chen, J.T. [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering] [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering

1996-10-01

317

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

NASA Astrophysics Data System (ADS)

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

Saikia, Dip

2008-04-01

318

Reproductive physiology  

USGS Publications Warehouse

Conclusions: Although the general pattern of avian physiology applies to cranes, we have identified many physiological mechanisms (e.g., effects of disturbance) that need further study. Studies with cranes are expensive compared to those done with domestic fowl because of the crane's larger size, low reproductive rate, and delayed sexual maturity. To summarize, the crane reproductive system is composed of physiological and anatomical elements whose function is controlled by an integrated neural-endocrine system. Males generally produce semen at a younger age than when females lay eggs. Eggs are laid in clutches of two (1 to 3), and females will lay additional clutches if the preceding clutches are removed. Both sexes build nests and incubate the eggs. Molt begins during incubation and body molt may be completed annually in breeding pairs. However, remiges are replaced sequentially over 2 to 3 years, or abruptly every 2 to 3 years in other species. Most immature birds replace their juvenal remiges over a 2 to 3 year period. Stress interferes with reproduction in cranes by reducing egg production or terminating the reproductive effort. In other birds, stress elevates corticosterone levels and decreases LHRH release. We know little about the physiological response of cranes to stress.

Gee, G.F.; Russman, S.E.

1996-01-01

319

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

1992-01-01

320

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.

2013-12-01

321

Characteristics of streamer discharge development between the dielectric-coated sphere-plane electrodes in water  

SciTech Connect

This paper presents the characteristics of the streamer discharge development between the dielectric-coated sphere-plane electrodes in water. In order to study the streamer propagation mechanism, the factors such as polarities, water conductivity, and ambient pressure were taken into consideration. Experimental results demonstrate that the water conductivity and amplitude of applied voltage both have a great influence on mean velocity and brightness of the streamer. When the ambient pressure decreases from 0.1 to 0.0065 MPa, the pressure has little influence on the mean velocities of the streamer in both distilled and tap water for fast streamer. The existence of dielectric coating causes a lower initiation voltage of the streamer for negative polarity than that for positive one. Also, the 10% breakdown voltage (U{sub 10%}) is decreased by 20% under the pressure of 0.0065 MPa than that under the pressure of 0.1 MPa in distilled water, while the U{sub 10%} is almost the same under different pressures in tap water. Based on the analysis of the discharge images and current waveforms as well as the above experimental results, it can be concluded that the streamer propagation is composed of the generation of the microbubbles and the discharge in the bubbles. For subsonic streamer, the generation of the bubbles is more likely a thermal process, whereas for supersonic streamer, the ionization and dissociation of water molecules in high electric field are involved in the bubble generation process.

Zhu Taiyun; Yang Lanjun; Jia Zhijie; Zhang Qiaogen [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, 28 West Xianning Road, Xi'an 710049 (China)

2008-12-01

322

[Contamination characteristics of polycyclic aromatic hydrocarbons (PAHs) in surface water from Jialing River in Chongqing].  

PubMed

To understand the composition, sources and contamination characteristics of PAHs in surface water from Jialing River in Chongqing, water samples were collected from 8 different sections in August 2009 and the concentrations of the 16 priority PAHs were determined using GC-MS. The results indicated that the concentration of Sigma PAHs (the total PAHs) in the water body ranged from 467.13 to 987.97 ng x L(-1), with an average concentration of 702.91 ng x L(-1). PAHs concentrations in surface waters were positively correlated with the dissolved organic carbon content. The predominant PAHs in the water body were 2-3 ring PAHs, accounting for 68.90% of Sigma PAHs. The ratios of specific PAHs revealed that the main PAHs source in Cuntan was the combustion of wood and coal, the origin of PAHs in Caotianmen was mostly petrogenic; whereas the main PAHs source in other sampling sections of Jialing River in Chongqing was petroleum combustion. Compared with other areas in China, the PAHs contamination in Jialing River around Chongqing was at a relatively low level, however, the concentrations of BaP in the surface water of 5 sampling sites exceeded the environmental quality standards for surface water in China. PMID:23002611

Cai, Wen-Liang; Luo, Gu-Yuan; Xu, Xiao-Yi; Du, Xian

2012-07-01

323

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

PubMed

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

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

2006-06-01

324

Physiological stress of high NH (4) (+) concentration in water column on the submersed macrophyte Vallisneria Natans L.  

PubMed

The submersed macrophyte, Vallisneria natans L., was cultured in laboratory with NH (4) (+) -enriched tap water (1 mg L(-1) NH(4)-N) for 2 months and the stressful effects of high ammonium (NH (4) (+) ) concentrations in the water column on this species was evaluated. The plant growth was severely inhibited by the NH (4) (+) supplement in the water column. The plant carbon and nitrogen metabolisms were disturbed by the NH (4) (+) supplement as indicated by the accumulation of free amino acids and the depletion of soluble carbohydrates in the plant tissues. The results suggested that high NH (4) (+) concentrations in the water column may hamper the restoration of submersed vegetation in eutrophic lakes. PMID:18941702

Cao, Te; Xie, Ping; Li, Zhongqiang; Ni, Leyi; Zhang, Meng; Xu, Jun

2009-03-01

325

Application of thermal flux for establishing soil–water characteristic curve of kaolin  

Microsoft Academic Search

Application of field and laboratory insertion tensiometers, pressure membrane extractor, PME, a dew point potentiameter, WP4, and a geotechnical centrifuge for establishing soil–water characteristic curve (SWCC) of fine-grained soils is well established. However, these techniques are quite elaborate, cumbersome to follow and resort to invasive and destructive techniques for moisture content determination. This calls for development of an alternate technique

B. Hanumantha Rao; D. N. Singh

2010-01-01

326

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

USGS Publications Warehouse

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

Fisher, J. C.

1982-01-01

327

Adsorptive characteristics of ionogenic aromatic pesticides in water on powdered activated carbon  

Microsoft Academic Search

The adsorptive characteristics of ionogenic pesticides on powdered activated carbon were described. The effects of pH on the adsorbabilities of MCPB (an acidic pesticide) and imazalil (a basic pesticide) onto powdered activated carbon (PAC) were evaluated by correlating 1-octanol-water partition coefficients (logPow) with the Freundlich adsorption constants over a pH range of 3?9. After being corrected with pH, the values

Jian-ying Hu; Takako Aizawa; Yutaka Ookubo; Takeshi Morita; Yasumoto Magara

1998-01-01

328

Convective heat transfer and flow characteristics of Cu-water nanofluid  

Microsoft Academic Search

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

Qiang Li; Yimin Xuan

2002-01-01

329

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

Microsoft Academic Search

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

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

2007-01-01

330

[Analysis on characteristics of red tide in Fujian coastal waters during the last 10 years].  

PubMed

There were 161 red tide events collected during the last 10 years from 2001 to 2010 in Fujian coastal waters. Comprehensive analysis was performed using statistical methods and the results indicated the following characteristics of the temporal and spatial distribution of red tide in Fujian coastal waters: (1) Outbreaks of red tide often occurred between April and September, and the peak period was in May and June. Most red tide events lasted for 2 to 4 days, and the affected area was below 50 square kilometers. The first outbreak of red tide tended to occur earlier in recent years, and the lasting time became longer. (2) There were 20 species of organisms causing the red tides in Fujian coastal waters, among which 10 species were Bacillariophyta, 9 species were Dinophyta and 1 species was Protozoa. Prorocentrum donghaiense was the most frequent cause of red tides, followed by Noctiluca scintillans, Skeletonema costatum and Chaetoceros sp.. The species caused red tides obeyed the succession law and there were always new species involved. (2) In terms of spatial distribution, outbreaks of red tides mainly occurred in the coastal waters of Ningde, Fuzhou and Xiamen. The species causing red tides were Prorocentrum donghaiense and Noctiluca in the coastal waters in the north of Pingtan, Fujian Province, Skeletonema costatum and Chaetoceros in the coastal waters in the south of Pingtan, Fujian Province. The comprehensive analysis of the characteristics of red tides during the last 10 years is expected to provide scientific and reasonable basis for the prevention, reduction and forecast of red tides in Fujian coastal waters. PMID:23002593

Li, Xue-Ding

2012-07-01

331

Chemical characteristics of waters in Karst Formations at the Oak Ridge Y-12 Plant  

SciTech Connect

Several waste disposal sites are located adjacent to or on a karst aquifer composed of the Cambrian Maynardville Limestone (Cmn) and the Cambrian Copper Ridge Dolomite (Ccr) at the U.S. Department of Energy Oak Ridge Y-12 Plant in Oak Ridge, TN. Highly variable chemical characteristics (i.e., hardness) can indicate that the portion of the aquifer tapped by a particular well is subject to a significant quick-flow component where recharge to the system is rapid and water levels and water quality change rapidly in response to precipitation events. Water zones in wells at the Y-12 Plant that exhibit quick-flow behavior (i.e., high hydraulic conductivity) are identified based on their geochemical characteristics and variability in geochemical parameters, and observations made during drilling of the wells. The chemical data used in this study consist of between one and 20 chemical analyses for each of 102 wells and multipart monitoring zones. Of these 102 water zones, 10 were consistently undersaturated with respect to calcite suggesting active dissolution. Repeat sampling of water zones shows that both supersaturation and undersaturation with respect to dolomite occurs in 46 water zones. Twelve of the zones had partial pressure of CO{sub 2} near atmospheric values suggesting limited interaction between recharge waters and the gases and solids in the vadose zone and aquifer, and hence, relatively short residence times. The preliminary data suggest that the Cmn is composed of a complicated network of interconnected, perhaps anastomosing, cavities. The degree of interconnection between the identified cavities is yet to be determined, although it is expected that there is a significant vertical and lateral interconnection between the cavities located at shallow depths in the Cnm throughout Bear Creek Valley and the Y-12 Plant area.

Shevenell, L.A. [Univ. of Nevada, Reno, NV (United States). Nevada Bureau of Mines and Geology

1994-11-01

332

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

PubMed Central

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

Taha, Mohd Raihan

2014-01-01

333

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

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

2012-01-01

334

Nitric oxide physiological responses and delivery mechanisms probed by water-soluble Roussin's red ester and {Fe(NO)2}10 DNIC.  

PubMed

Dinitrosyl-iron complexes (DNICs) are stable carriers for nitric oxide (NO), an important biological signaling molecule and regulator. However, the insolubility of synthetic DNICs, such as Roussin's red ester (RRE), in water has impaired efforts to unravel their biological functions. Here, we report a water-soluble and structurally well-characterized RRE [Fe(mu-SC2H4COOH)(NO)2]2 (DNIC-1) and a {Fe(NO)2}(10) DNIC [(PPh2(Ph-3-SO3Na))2Fe(NO)2] (DNIC-2), their NO-induced protein regulation, and their cellular uptake mechanism using immortalized vascular endothelial cells as a model. Compared with the most common NO donor, S-nitroso-N-acetyl-penicillamine (SNAP), the in vitro NO release assay showed that both DNICs acted as much slower yet higher stoichiometric NO-release agents with low cytotoxicity (IC50 > 1 mM). Furthermore, L-cysteine facilitated NO release from SNAP and DNIC-1, but not DNIC-2, in a dose- and time-dependent manner. EPR spectroscopic analysis showed, for the first time, that intact DNIC-1 can either diffuse or be transported into cells independently and can transform to either paramagnetic protein bound DNIC in the presence of serum or [DNIC-(Cys)2] with excess L-cysteine under serum-free conditions. Both DNICs subsequently induced NO-dependent upregulation of cellular heat shock protein 70 and in vivo protein S-nitrosylation. We conclude that both novel water-soluble DNICs have potential to release physiologically relevant quantities of NO and can be a good model for deciphering how iron-sulfur-nitrosyl compounds permeate into the cell membrane and for elucidating their physiological significance. PMID:18661983

Chen, Yi-Ju; Ku, Wei-Chi; Feng, Li-Ting; Tsai, Ming-Li; Hsieh, Chung-Hung; Hsu, Wen-Hwei; Liaw, Wen-Feng; Hung, Chen-Hsiung; Chen, Yu-Ju

2008-08-20

335

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.

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

2012-01-01

336

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

USGS Publications Warehouse

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

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

1995-01-01

337

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

Microsoft Academic Search

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

K. R. Reddy; W. F. Debusk

1984-01-01

338

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

SciTech Connect

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

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

1988-11-01

339

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

PubMed

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

2012-03-01

340

Physiological Interactions  

Microsoft Academic Search

\\u000a Improvement in both temporal and spatial resolution of MDCT has brought the ability to explore both the heart and lung within\\u000a a single examination and opened the field of functional evaluation. However, interactions between heart and lung have long\\u000a been identified as important physiological phenomena in pathology (Pinsky 2005). For the radiologist, they are involved in difficulties of interpretation in

Francois Laurent; Michel Montaudon

341

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

PubMed

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

2014-02-01

342

A new cadmium reduction device for the microplate determination of nitrate in water, soil, plant tissue, and physiological fluids.  

PubMed

A reusable catalytic reductor consisting of 96 copperized-cadmium pins attached to a microplate lid was developed to simultaneously reduce nitrate (NO3-) to nitrite (NO2-) in all wells of a standard microplate. The resulting NO2- is analyzed colorimetrically by the Griess reaction using a microplate reader. Nitrate data from groundwater samples analyzed using the new device correlated well with data obtained by ion chromatography (r2 = 0.9959). Soil and plant tissue samples previously analyzed for NO3- in an interlaboratory validation study sponsored by the Soil Science Society of America were also analyzed using the new technique. For the soil sample set, the data are shown to correlate well with the other methods used (r2 = 0.9976). Plant data correlated less well, especially for samples containing low concentrations of NO3-. Reasons for these discrepancies are discussed, and new techniques to increase the accuracy of the analysis are explored. In addition, a method is presented for analyzing NO3- in physiological fluids (blood serum and urine) after matrix modification with Somogyi's reagent. A protocol for statistical validation of data when analyzing samples with complex matrixes is also established. The simplicity, adaptability, and low cost of the device indicate its potential for widespread application. PMID:22320098

Crutchfield, James D; Grove, John H

2011-01-01

343

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

PubMed

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

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

2004-03-01

344

The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans  

PubMed Central

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.

Adeva-Andany, Maria M.; Carneiro-Freire, Natalia; Donapetry-Garcia, Cristobal; Ranal-Muino, Eva; Lopez-Pereiro, Yosua

2014-01-01

345

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.

2014-01-01

346

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

NASA Astrophysics Data System (ADS)

In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these unpredictable rainfall conditions, plant hydraulic traits (xylem and stomatal response to water availability) and morphological features (leaf and sapwood areas) must be coordinated - thus providing an ecohydrological interpretation of observed coordination (or homeostasis) among hydraulic traits. Moreover, the combinations of hydraulic traits and responses to drought that are optimal are found to depend on both total rainfall and its distribution during the growing season. Both drier conditions and more intense rainfall events interspaced by longer dry periods favor plants with high resistance to cavitation and delayed stomatal closure as soils dry. In contrast, plants in mesic conditions benefit from cavitation prevention through earlier stomatal closure. The proposed ecohydrological optimality criteria can be used as analytical tools to interpret variability in plant water use and predict trends in plant productivity and species composition under future climates.

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

2013-12-01

347

Pathologic and physiologic phimosis  

PubMed Central

OBJECTIVE To review the differences between physiologic and pathologic phimosis, review proper foreskin care, and discuss when it is appropriate to seek consultation regarding a phimotic foreskin. SOURCES OF INFORMATION This paper is based on selected findings from a MEDLINE search for literature on phimosis and circumcision referrals and on our experience at the Children’s Hospital of Eastern Ontario Urology Clinic. MeSH headings used in our MEDLINE search included “phimosis,” “referral and consultation,” and “circumcision.” Most of the available articles about phimosis and foreskin referrals were retrospective reviews and cohort studies (levels II and III evidence). MAIN MESSAGE Phimosis is defined as the inability to retract the foreskin. Differentiating between physiologic and pathologic phimosis is important, as the former is managed conservatively and the latter requires surgical intervention. Great anxiety exists among patients and parentsregarding non-retractile foreskins. Most phimosis referrals seen in pediatric urology clinics are normal physiologically phimotic foreskins. Referrals of patients with physiologic phimosis to urology clinics can create anxiety about the need for surgery among patients and parents, while unnecessarily expanding the waiting list for specialty assessment. Uncircumcised penises require no special care. With normal washing, using soap and water, and gentle retraction during urination and bathing, most foreskins will become retractile over time. CONCLUSION Physiologic phimosis is often seen by family physicians. These patients and their parents require reassurance of normalcy and reinforcement of proper preputial hygiene. Consultation should be sought when evidence of pathologic phimosis is present, as this requires surgical management.

McGregor, Thomas B.; Pike, John G.; Leonard, Michael P.

2007-01-01

348

Interference of Origanum vulgare L. essential oil on the growth and some physiological characteristics of Staphylococcus aureus strains isolated from foods  

Microsoft Academic Search

The aim of this study was to investigate the chemical composition of Origanum vulgare L. essential oil, the inhibitory effect of the oil on the cell viability of Staphylococcus aureus strains isolated from foods, and the influence of sub-inhibitory concentrations of the oil on some physiological attributes of these strains. GC–MS analysis showed that carvacrol (57.71%) was the most prevalent

Jefferson Carneiro de Barros; Maria Lúcia da Conceição; Nelson Justino Gomes Neto; Ana Caroliny Vieira da Costa; José Pinto Siqueira; Irinaldo Diniz Basílio; Evandro Leite de Souza

2009-01-01

349

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

PubMed

Adjustment of pH from 6.4 to neutrality improved gelling ability and water-holding capacity of twice water-washed, minced chicken-breast muscle significantly at physiological ionic strength, at which the majority of the myofibrillar proteins, including myosin, are not soluble. A strain value of 2.2 was obtained at neutral pH. Myofibrils were the main components of the gel network at both pH 6.4 and 7.0; however, the myofibrillar distribution varied with the pH value. At pH 6.4, myofibrils formed a network of localized aggregates leaving large voids between, whereas at neutral pH, an evenly distributed network of myofibrils was formed. In addition, at neutral pH, a network of fine strands was found within the network of myofibrils. The network was much less developed at pH 6.4. The thin and thick filaments within each myofibrillar structure were disorganized at both pH values. The intramyofibrillar spaces were larger at neutral pH than at pH 6.4. It was proposed that adjustment of pH to neutrality increased electrostatic repulsion leading to a more even distribution of the myofibrillar proteins, a key factor responsible for the improved gel strength and water-holding capacity. PMID:11513691

Feng, Y; Hultin, H O

2001-08-01

350

Comparative studies on physiological and biochemical adaptation of Taxodium distichum and Taxodium ascendens seedlings to different soil water regimes  

Microsoft Academic Search

Responses of baldcypress (Taxodium distichum) and pondcypress (Taxodium ascendens) seedlings in leaf gas exchange and root metabolism to a wide range of hydrological regimes were studied. Four water treatments\\u000a included control (C), mild drought (MD), wet soil (WS) and flooding (FL). Both species showed no significant change in net\\u000a photosynthetic rate (Pn) in response to flooding in contrast to significant

Changxiao Li; Zhangcheng Zhong; Yanghui Geng; Rebecca Schneider

2010-01-01

351

Predicting stream-water quality using catchment and soil chemical characteristics.  

PubMed

The distribution and chemistry of soils in 10 upland catchments in NE Scotland have been used to develop a means of predicting minimum, maximum and mean concentrations of calcium and hydrogen ions in streams. The approach is based on the control of stream-water chemistry by soil chemical properties. Stream-water chemistry was monitored over a two-year period. Each catchment was surveyed and soils sampled to characterize the chemistry of the main soil units. Stream-water chemical parameters are related to the chemical characteristics of the upper and lower soil horizons in the catchments. The contribution of each soil unit is assessed using randomly generated flow paths. Soil chemistry is weighted according to the distribution of soils in the immediate vicinity of the stream. In this paper the approach is largely confined to the prediction of minimum, maximum and mean concentrations of calcium ions in stream waters. In the longer term, the approach may have the potential to predict what effects changes in soil chemistry and management practice (drainage, ploughing) will have on water quality in upland catchments. PMID:15091967

Billett, M F; Cresser, M S

1992-01-01

352

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

PubMed

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

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

2010-01-01

353

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.

1972-01-01

354

Freezing Characteristics of Layered Air-Water Flow in a Horizontal Circular Tube  

NASA Astrophysics Data System (ADS)

An experimental study has been performed to investigate characteristics of the freezing heat transfer of layered air-water flow in a circular tube, in which cooled air and water co-flow. The experiments were carried out under a variety of conditions of water discharge, water temperature, tube-wall temperature, air discharge, and water level. Particular attention was focused on photographic visual observations of the developing ice layer along the tube wall. It was in general observed that there were two different regions characterizing the ice formation, one of which was the freeze-off region, and the other was the steady-state region. The onset of freeze-off was found to be predicted by the equation Fo=1.85Rew0.142Rea-0.03?c-1.01(H/D)1.31. It was also found that the mean Nusselt number might be described as the following equation : Num=2.26×10-1Rew0.80Rea-0.03thetac-0.788(H/D)0.331.

Fukusako, Shoichiro; Takahashi, Masato

355

Freezing Characteristics of Molding Sand with Water by Cold Air Flow for Freeze Mold  

NASA Astrophysics Data System (ADS)

This paper reports the freezing characteristics of sand molded with "the freeze mold method". The freeze mold method is the casting process where little water is added to cast sand then they are frozen and become harden as a mold. Instead of using organic hardener, this molding technology possibly reduces resources and environment loading. We aimed at the practical application of the freeze mold method and chose cold airflow as the medium taking heat away from the mold. At first the sand with water was filled into a rectangular container that is the test section. Then cold air flowed into the container. Consequently, the mold was cooled and frozen by the cold airflow. The freezing behavior of the sample by cold airflow was investigated experimentally under the conditions of added water amount, superficial velocity, inflow air temperature and fixed bed height. As a result, the freezing completion time becomes long as the added water amount increases. However, an increase in the added water amount doesn't influence the pressure loss of the test section so much. Moreover, the empirical equation was derived to predict the freezing completion time.

Horibe, Akihiko; Inaba, Hideo; Haruki, Naoto; Miyagawa, Yasunori

356

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

NASA Astrophysics Data System (ADS)

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

La Baugh, James W.

1986-10-01

357

Water mass characteristics in the deep layers of the western Ionian Basin observed during May 2003  

NASA Astrophysics Data System (ADS)

CTD measurements carried out in the southern Adriatic Sea and in the western Ionian basin (Eurafrican Mediterranean Sea) during May 2003 by the German research vessel Poseidon (Poseidon cruise 298) and numerical simulations are used to elucidate aspects of the abyssal circulation of this oceanic region. The observations reveal that dense waters of Adriatic origin were strongly diluted along their way on the Italian continental slope, whilst their characteristics remained better preserved in a region located further east. Numerical simulations carried out by means of a nonlinear, reduced-gravity plume model confirm the observations and contribute to explain their cause: The very steep topographic slope along the Italian shelf in the region of the Gulf of Taranto induces strong entrainment of intermediate waters in the bottom layers. Instead, the bottom waters of Adriatic origin which, along their path further east, encounter gentler topographic variations, are weakly diluted by turbulent mixing and, therefore, better preserve their original characteristics. The remarkable differences in the simulated turbulent mixing along these two different paths are accentuated by the presence of a noticeable zonal gradient of potential density existing in the near-bottom layers of the northern Ionian basin.

Hainbucher, D.; Rubino, A.; Klein, B.

2006-03-01

358

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

NASA Technical Reports Server (NTRS)

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

1966-01-01

359

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

PubMed Central

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

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

2007-01-01

360

Characteristics of melt water discharge in the Glacier No. 1 basin, headwater of Urumqi River  

NASA Astrophysics Data System (ADS)

Characteristics of the daily melt water discharge cycle and the relation between melt water discharge, air temperature, and precipitation are analyzed based on observation data during 2001-2005 in the Glacier No. 1 basin at the headwater of the Urumqi River, Tianshan Mountains (hereafter, Glacier No. 1). The results indicate that the daytime and nighttime discharges were less during the preliminary stage of melting in May, and became strong following the ablation period (July-August). The daytime and nighttime discharges in the same month varied year-over-year, and the daily discharge cycles in different months of the summer were dissimilar. The mean daytime/nighttime discharges were somewhat related to the mean nighttime air temperature (Tn), but were not significantly related to the amount of precipitation. In the daily cycle of average discharges in the summer months during 2001-2005, the maximum discharges occurred in the afternoons and evenings, and the minimum discharges occurred in the mornings. The daily discharge peaks lagged behind the time of maximum melting (maximum air temperature) on selected clear-weather days in different months in different years. This was related to the melt water flow distance inside and underneath the glacier and the structure of the internal drainage net, and may also have been influenced by the weather prior to and after the observed consecutive clear-weather days. The monthly mean daytime discharge was generally greater than the nighttime discharge, primarily because cloudy and rainy weather and lower air temperatures led to less melt water, and precipitation could not make up the loss of discharge from melt water. Daytime melt water contributed only slightly to nighttime discharge due to the short time lag caused by melt water flow distance.

Mingjie, Gao; Tianding, Han; Baisheng, Ye; Keqin, Jiao

2013-05-01

361

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

PubMed

Penicillium glabrum is a ubiquitous fungus distributed world wide. This fungus is a frequent contaminant in the food manufacturing industry. Environmental factors such as temperature, water activity and pH have a great influence on fungal development. In this study, a strain of P. glabrum referenced to as LCP 08.5568, has been isolated from a bottle of aromatized mineral water. The effects of temperature, a(w) and pH on radial growth rate were assessed on Czapeck Yeast Agar (CYA) medium. Models derived from the cardinal model with inflection [Rosso et al., 1993 An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. J. Theor. Bio. 162, 447-463.] were used to fit the experimental data and determine for each factor, the cardinal parameters (minimum, optimum and maximum). Precise characterisation of the growth conditions for such a fungal contaminant, has an evident interest to understand and to prevent spoilage of food products. PMID:19233496

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

2009-04-15

362

The characteristics of fluid flow in beds of small glass particles spouted with water  

Microsoft Academic Search

The characteristics of beds of small glass particles 0.28, 0.46 and 0.77mm in diameter spouted with water were studied in\\u000a a half-cylindrical column 51mm in diameter with inlet tube diameter of 3.2mm. The minimum spouting velocity, bed pressure\\u000a drop at minimum spouting and spout diameter were measured. Assuming Darcy flow, the fluid flow in the annulus is modeled and\\u000a shown

Seung Jai Kim

1984-01-01

363

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

USGS Publications Warehouse

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

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

1995-01-01

364

Characteristics of water use in Fagus crenata among 3 sites throughout Japan  

NASA Astrophysics Data System (ADS)

Japanese beech is widely distributed throughout Japan, and investigating adaptation of Japanese beech to the variety of atmospheric and soil water conditions is important to understand gas exchange of forest ecosystems under climate exchange. Therefore, the purpose of this study is to clarify geographical variation in control transpiration of Japanese beech trees under various climate conditions. Toward this goal, canopy stomatal conductance at tree level and hydraulic conductivity of the trees were evaluated in 3 beech stands. Stomata of beech trees with high hydraulic conductivity have high gas exchange ability, and its stomata respond to D sensitively to avoid loss more water and cavitations at high D. On the other hand, beech trees in SH have smaller hydraulic conductivity with low sensitivity to D to keep stomata opened under high D condition. The relationship between transpiration characteristics and morphological differences among sites will be discussed.

Tateishi, M.; Kumagai, T.; Utsumi, Y.; Suyama, Y.; Hiura, T.

2009-12-01

365

Dynamic characteristics of laser-induced vapor bubble formation in water based on high speed camera  

NASA Astrophysics Data System (ADS)

In clinical practice, laser ablation usually works under liquid environment such as water, blood or their mixture. Laser-induced vapor bubble or bubble formation and its consequent dynamics were believed to have important influence on tissue ablation. In the paper, the dynamic process of vapor bubble formation and consequently collapse induced by pulsed Ho:YAG laser in static water was investigated by using high-speed camera. The results showed that vapor channel / bubble can be produced with pulsed Ho:YAG laser, and the whole dynamic process of vapor bubble formation, pulsation and consequently collapse can be monitored by using high-speed camera. The dynamic characteristics of vapor bubble, such as pulsation period, the maximum depth and width were determined. The dependence of above dynamic parameters on incident radiant exposure was also presented. Based on which, the influence of vapor bubble on hard tissue ablation was discussed.

Zhang, Xian-zeng; Guo, Wenqing; Zhan, Zhenlin; Xie, Shusen

2013-08-01

366

No tillage effect on water retention characteristics of soil aggregates in rainfed semiarid conditions.  

NASA Astrophysics Data System (ADS)

The evaluation of changes in soil moisture retention characteristics associated to alterations in soil structure is of great interest in tillage studies. Most of these studies have evaluated soil properties in samples of total soil but not in individual aggregates. However, soil behavior at a macroscale level depends on the aggregate properties. A better knowledge of aggregate characteristics, as the water retention properties, will help to explain, for example, the response of soil to tillage, compaction and crop growth, and hence, to plan adequate soil management practices. In this study we determine the water retention curve of soil aggregates of different sizes from a soil under two tillage systems (conventional and no tillage). The study was carried out in a silty clay loam soil of semiarid Aragon (NE Spain). Two tillage systems were compared: no tillage (NT) and conventional tillage with mouldboard plough (CT). Water retention curves (WRC) were determined for soil surface aggregates (0-5 cm) of three different sizes (8-4, 4-2 and 2-1 mm in diameter) by using the TDR-pressure cell (Moret et al. 2008. Soil Till. Res, 100, 114-119). The TDR-pressure cell is a non-destructive method which permits determining WRC with the only one and same soil sample. Thus, the pressure cell was filled with aggregates up to 4 cm height, weighted and wetted to saturation from the bottom. Pressure steps were sequentially applied at -0.5, -1.5, -3, -5, -10, -33, -100, -300 kPa, and water content of each aggregate sample was measured gravimetrically and by TDR 24 h after starting each pressure head step. The volume of the sample within the cell was also determined at this moment in order to obtain the bulk density and thus calculate the volumetric water content. A good relationship was obtained between the volumetric water content calculated from the gravimetric water content and the corresponding values measured by TDR (r2=0.907; p?0.05). Within the same tillage treatment, no significant differences in WRC were found among soil aggregate sizes. Soil aggregates under CT retained more water at lower pressure heads in all aggregate sizes; in contrast the retention was more effective in those from NT at high pressure level. The extensive structural degradation of the CT aggregates observed during wetting with the consequent decrease in the soil volume within the transparent cell, can help to explain the different behaviour of both soils. The CT aggregates were probably disintegrated by slaking, causing a reduction in water drainage and, therefore, an increase in soil water content at low pressure heads. This idea was also confirmed with the application of the double exponential function proposed by Dexter et al. (2008. Geoderma 173, 243-253). The WRC curves measured by TDR were successfully fitted to the theoretical model proposed by Dexter (r2=0.986; p?0.05). Thus, the model estimated that the large porosity between aggregates retain slightly more water under CT (0.36-0.39 m3 m-3) than under NT (0.31-0.35 m3 m-3). On the contrary, pores inside the aggregates tend to storage more water in NT (0.16-0.20 m3 m-3vs. 0.13-0.17 m3 m-3 in CT). These results show the suitability of NT to reduce the risk of soil crusting and compaction in agricultural lands of Aragón.

Blanco-Moure, Nuria; López, M. Victoria; Moret, David

2010-05-01

367

Disease-associated pathophysiologic structures in pediatric rheumatic diseases show characteristics of scale-free networks seen in physiologic systems: implications for pathogenesis and treatment  

PubMed Central

Background While standard reductionist approaches have provided some insights into specific gene polymorphisms and molecular pathways involved in disease pathogenesis, our understanding of complex traits such as atherosclerosis or type 2 diabetes remains incomplete. Gene expression profiling provides an unprecedented opportunity to understand complex human diseases by providing a global view of the multiple interactions across the genome that are likely to contribute to disease pathogenesis. Thus, the goal of gene expression profiling is not to generate lists of differentially expressed genes, but to identify the physiologic or pathogenic processes and structures represented in the expression profile. Methods RNA was separately extracted from peripheral blood neutrophils and mononuclear leukocytes, labeled, and hybridized to genome level microarrays to generate expression profiles of children with polyarticular juvenile idiopathic arthritis, juvenile dermatomyositis relative to childhood controls. Statistically significantly differentially expressed genes were identified from samples of each disease relative to controls. Functional network analysis identified interactions between products of these differentially expressed genes. Results In silico models of both diseases demonstrated similar features with properties of scale-free networks previously described in physiologic systems. These networks were observable in both cells of the innate immune system (neutrophils) and cells of the adaptive immune system (peripheral blood mononuclear cells). Conclusion Genome-level transcriptional profiling from childhood onset rheumatic diseases suggested complex interactions in two arms of the immune system in both diseases. The disease associated networks showed scale-free network patterns similar to those reported in normal physiology. We postulate that these features have important implications for therapy as such networks are relatively resistant to perturbation.

Frank, Mark Barton; Wang, Shirley; Aggarwal, Amita; Knowlton, Nicholas; Jiang, Kaiyu; Chen, Yanmin; McKee, Ryan; Chaser, Brad; McGhee, Timothy; Osban, Jeanette; Jarvis, James N

2009-01-01

368

Carotenoid supplementation and GnRH challenges influence female endocrine physiology, immune function, and egg-yolk characteristics in Japanese quail (Coturnix japonica).  

PubMed

Androgens and carotenoids circulating in plasma affect the physiology and behavior of vertebrates. Much is known about control mechanisms and functions of each of these substances, yet their interactive effects are not well understood. Here we examine possible additive, multiplicative, and interactive effects of testosterone and carotenoids on female endocrine physiology, immunocompetence, and investment in eggs by simultaneously manipulating levels of testosterone [via gonadotropin releasing hormone (GnRH) challenges] and carotenoids (via diet supplementation) in captive female Japanese quail (Coturnix japonica). Females were randomly assigned to one of four treatments: carotenoid supplementation, GnRH challenge, GnRH challenge + carotenoid supplementation, or control. Carotenoid supplementation significantly increased circulating plasma carotenoid levels and acquired immune system performance, but not innate immunity. GnRH challenges elevated circulating testosterone and carotenoid levels, and induced immunosuppression in females. However, females in the GnRH challenge + carotenoid supplementation treatment had higher cell-mediated immune responses than control females and similar responses to those of carotenoid-supplemented females. Hence, availability of carotenoids in female quail seemed to counteract immunosuppressive effects of GnRH challenges. Our results provide further evidence for synergistic effects of carotenoids and testosterone on endocrine physiology and immune function in female birds. Elevated plasma testosterone or carotenoids levels resulted in increased deposition of those compounds to eggs, respectively. Furthermore, because we found that concentrations of testosterone and carotenoids in yolks were correlated within each treatment group, differential deposition of hormones and carotenoids in eggs may not only respond to surrounding social and environmental conditions, but also to other components of the egg. PMID:22237302

Peluc, Susana I; Reed, Wendy L; McGraw, Kevin J; Gibbs, Penelope

2012-07-01

369

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

370

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

NASA Astrophysics Data System (ADS)

ELECTRIC DISCHARGE IN THE WATER: PHYSICS OF FORMATION AND RADIATIVE CHARACTERISTICS 2.10. Lighting plasmas. 2.26. Other plasma topics. A.M.Anpilov, E.M.Barkhudarov, Yu.N.Kozlov, I.A.Kossyi, V.P.Silakov and S.M.Temchin Two types of electric discharge in the water have been investigated: discharge between two electrodes and multielectrode gliding surface discharge. Results are presented from experimental studies of the prebreakdown phase of an electric discharge between the point (anode) and plane (cathode) electrodes immersed in the water with different initial conductivity. When a high-voltage pulse is applied, the induced conductivity is detected in the discharge gap. Its value is one order of magnitude higher than the initial one. It is shown that the induced conductivity increases almost linearly with initial conductivity. The induced conductivity correlates with the UV emission from the cathode surface. A qualitative analysis of the experimental results is performed. Investigations of a spectrum of radiation of discharge in water have been carried out. On the base of broadening and shifting of atomic hydrogen and oxygen lines electron density in a prebreakdown as well as breakdown stages has been determined. Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190 £l£430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the gliding surface discharge in water for its disinfection is analysed.

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

2004-09-01

371

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

PubMed

In this study, we investigated adsorption characteristics of nine selected micropollutants (six pharmaceuticals, two pesticides, and one endocrine disruptor) in water using an activated carbon. The effects of carbon dosage, contact time, pH, DOM (dissolved organic matter), and temperature on the adsorption removal of micropollutants were examined. Increasing carbon dosage and contact time enhanced the removal of micropollutants. Sorption coefficients of hydrophilic compounds (caffeine, acetaminophen, sulfamethoxazole, and sulfamethazine) fit a linear isotherm and hydrophobic compounds (naproxen, diclofenac, 2, 4-D, triclocarban, and atrazine) fit a Freundlich isotherm. The removal of hydrophobic pollutants and caffeine were independent of pH changes, but acetaminophen, sulfamethazine, and sulfamethoxazole were adsorbed by mainly electrostatic interaction with activated carbon and so were affected by pH. The decrease in adsorption removal in surface water samples was observed and this decrease was more significant for hydrophobic than hydrophilic compounds. The decline in the adsorption capacity in surface water samples is caused by the competitive inhibition of DOM with micropollutants onto activated carbon. Low temperature (5°C) also decreased the adsorption removal of micropollutants, and affected hydrophobic compounds more than hydrophilic compounds. The results obtained in this study can be applied to optimize the adsorption capacities of micropollutants using activated carbon in water treatment process. PMID:24572271

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

2014-04-15

372

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

SciTech Connect

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. 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. 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. 44 refs., 1 fig., 8 tabs.

Bradfield, A.D.

1986-01-01

373

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

SciTech Connect

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

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

2008-04-15

374

Population Characteristics of the Channel, Flathead, and Blue Catfish in the Indiana Illinois Interjurisdictional Waters of the Wabash River.  

National Technical Information Service (NTIS)

The objective of this project was to describe the population characteristics of the channel (Ictalurus punctatus), flathead (Pylodictis olivaris) and blue (Ictalurus furcatus) catfish in the Indiana-Illinois interjurisdictional waters of the Wabash River....

T. E. Lauer

1999-01-01

375

Environmental Characteristics and Water Quality of Hydrologic Benchmark Network Stations in the Eastern United States, 1963-95.  

National Technical Information Service (NTIS)

The report describes the environmental characteristics and water quality at 16 benchmark basins in the Eastern United States. The basins and physiographic provinces are as follows: the Wild River, Maine, in the New England Province; Esopus Creek, New York...

M. A. Mast J. T. Turk

1999-01-01

376

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.

1993-01-01

377

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

378

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

Microsoft Academic Search

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

David B. Herbst

2001-01-01

379

[Spatial distribution characteristics and environmental effect of N and P in water body of Taihu Lake].  

PubMed

The characteristics of spatial distribution of nitrogen and phosphorus in water were studied. The results showed that concentrations of total nitrogen/phosphorus in water from Meiliang Bay, Zhusan Bay, Gonghu Bay, West and Central Taihu Lake were obviously higher than those from any other region of Taihu Lake. The spatial distribution of dissolved nitrogen/phosphorus and detritus nitrogen/phosphorus was consistent with that of total nitrogen/phosphorus. The concentrations of dissolved nitrogen and detritus nitrogen significantly correlated with those of total nitrogen with rDN = 0.8192 and rDeN = 0.6969, respectively; the concentrations of dissolved and detritus phosphorus in water also significantly correlated with that of total phosphorus with rDP = 0.7477 and rDeP = 0.9260, respectively. The discrepancy in spatial distribution of chlorophyll a (Chla) in water was distinctly obvious, the highest level appeared in West Taihu Lake (179.2 microg x L(-1) +/- 25.9 microg x L(-1)), and the lowest in East Taihu Lake (11.3 microg x L(-1) +/- 2.7 microg x L(-1)). There were significantly linear relationships between total nitrogen, detritus nitrogen, total phosphorus, dissolved phosphorus, detritus phosphorus, permanganate index, pH value and suspended solids and the content of Chla with rTN = 0.6622, rDeN = 0.8739, rTP = 0.8130, rDP = 0.4077 and rDeP = 0.8781, rCOD = 0.8689, rpH = 0.5173 and rSS = 0.5334, respectively; while dissolved nitrogen, electric conductivity and alkalinity did not affect Chla in water from Taihu Lake. PMID:19256372

Deng, Jian-cai; Chen, Qiao; Zhai, Shui-jing; Yang, Xu-chang; Han, Hong-juan; Hu, Wei-ping

2008-12-01

380

[Characteristics and comparative study of a new drinking-water defluoridation adsorbent Bio-F].  

PubMed

To evaluate the application potentiality pf a new type drinking-water defluoridation adsorbent Bio-F, comparative study on the defluoridation characteristics of common adsorbents activated alumina (AA), bone char (BC), activated clinoptilolite (AC) with Bio-F was conducted. The defluoridation characteristics under different conditions, such as particle diameter, pH, retention time, fluorine concentration, regeneration stability, were investigated by continuous-flow column experiments and static tests. The defluoridation efficiency of high fluoride underground water by four types of adsorbents was also compared. The results showed that F(-) adsorption kinetics of Bio-F fitted the Lagergren First-order equation (R2 = 0.9580). F(-) adsorption by Bio-F was found to fit the Langmuir adsorption isotherm (R2 = 0.9992). The results indicated that the static defluoridation capacity (DC) of Bio-F was 4.0883 mg x g(-1), which was about 1.8 folds and 5.8 folds of those of AA and AC respectively. DC of all four adsorbents was positively correlated with F(-) concentration and negatively correlated with particle size. High concentration of CO3(2-) and HCO3(-) reduced the DC of Bio-F (p < 0.05), while high concentration of Ca2+, NO3(-), HPO4(2-) favored defluoridation by Bio-F (p < 0.001). The optimal retention time of Bio-F was 3-4 min, which was less than that of AC (20 min) and AA (11 min). The DC of Bio-F remained relatively stable in pH 4.0-9.0 and in regeneration since the DC variation was not more than 15%. The above results indicated that Bio-F was superior to AA, BC and AC in drinking-water defluoridation. PMID:19545002

Zhu, Chi; Zhao, Liang-Yuan; Yuan, Heng; Yang, Han-Ying; Li, Ang; Wang, Peng; Yang, Shao

2009-04-15

381

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

PubMed

This paper presents an experimental investigation on the convective heat transfer and friction factor characteristics of CNT/water nanofluid through a circular tube fitted with helical screw tape inserts with constant heat flux under laminar flow condition. Nanofluids of 0.1% and 0.2% volume fractions are prepared by two step method. Thermo-physical properties like thermal conductivity and viscosity are measured by using KD2 thermal property analyzer and Brooke field cone and plate viscometer respectively. From the measurements, it is found that the viscosity increase is substantially higher than the increase in the thermal conductivity. The helical screw tape insets with twist ratios Y = 3, 2.44 and 1.78 are used to study the convective heat transfer and friction factor characteristics under laminar flow in the Reynolds number range of 520-2500. It is observed that, in a plain tube, maximum enhancement in Nusselt number for 0.1% and 0.2% volume fractions of nanofluids compared to pure water is 15% and 32% respectively. With the use of inserts, maximum enhancement in Nusselt number corresponding to twist ratios of 1.78, 2.44 and 3 are obtained as 8%, 16% and 4.6% for 0.1% volume fraction of nanofluid and 5%, 4% and 12% for 0.2% volume fraction of nanofluid when compared with water in plain tube. Thermal performance factor evaluation revealed that the values at all Reynolds number for all twist ratios and both concentration of CNT nanofluid are greater than unity which indicates that helical screw tape inserts with twist ratios considered are feasible in terms of energy saving in laminar flow. PMID:24745238

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

2014-03-01

382

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)

2009-07-15

383

Physical and Water-Quality Characteristics Affecting Trout-Spawning Habitat in the Quashnet River, Cape Cod, Massachusetts.  

National Technical Information Service (NTIS)

The report presents the results of a reconnaissance study of the physical and water-quality characteristics of the Quashnet River by the U.S. Geological Survey, in cooperation with the Mashpee Water District, in 1988 and 1989. The concerns are that the de...

Y. H. Baevsky

1991-01-01

384

The characteristics of expansins in wheat coleoptiles and their responses to water stress.  

PubMed

As the key regulators of cell wall extension during plant growth, expansins play an important role in regulating the development and response of plants to adverse environment. The characteristics of expansins in wheat coleoptiles and their responses to water stress were studied. Expansin proteins were extracted from wheat coleoptiles by the methods of Hepes or SDS. The activities of expansins were measured with an improved extensometer and the amount of expansins was measured by immunoblot analysis with the expansin antibody. The results showed that in coleoptiles, the extension of native cell walls depended on acidic pH, and the expansins were found to be located at cell walls by location analysis. Expansins from wheat coleoptiles could induce cell wall extension both of cucumber hypocotyls and coleoptiles, and vice versa, albeit with differences noted in extension activity. The changes in activity and abundance of expansins in wheat coleoptiles in response to water stress suggest that expansins may play a significant role in the tolerance of wheat plants to water stress. PMID:17960043

Gao, Qiang; Guo, Qi-Fang; Xing, Shi-Chao; Zhao, Mei-Rong; Li, Feng; Wang, Wei

2007-10-01

385

Spatial and seasonal characteristics of river water chemistry in the Taizi River in Northeast China.  

PubMed

Anthropogenic activities have led to water quality deterioration in many parts of the world, especially in Northeast China. The current work investigated the spatiotemporal variations of water quality in the Taizi River by multivariate statistical analysis of data from the 67 sampling sites in the mainstream and major tributaries of the river during dry and rainy seasons. One-way analysis of variance indicated that the 20 measured variables (except pH, 5-day biological oxygen demand, permanganate index, and chloride, orthophosphate, and total phosphorus concentrations) showed significant seasonal (p???0.05) and spatial (p?characteristics of water chemistry, organic pollution, phosphorous pollution, denitrification effect, and nitrogen pollution. The results indicate that river pollution in Northeast China was mainly from natural and/or anthropogenic sources, e.g., rainfall, domestic wastewater, agricultural runoff, and industrial discharge. PMID:24477615

Bu, Hongmei; Meng, Wei; Zhang, Yuan

2014-06-01

386

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

2014-05-01

387

Receiver Operating Characteristic Curve Analysis of Beach Water Quality Indicator Variables  

PubMed Central

Receiver operating characteristic (ROC) curve analysis is a simple and effective means to compare the accuracies of indicator variables of bacterial beach water quality. The indicator variables examined in this study were previous day's Enterococcus density and antecedent rainfall at 24, 48, and 96 h. Daily Enterococcus densities and 15-min rainfall values were collected during a 5-year (1996 to 2000) study of four Boston Harbor beaches. The indicator variables were assessed for their ability to correctly classify water as suitable or unsuitable for swimming at a maximum threshold Enterococcus density of 104 CFU/100 ml. Sensitivity and specificity values were determined for each unique previous day's Enterococcus density and antecedent rainfall volume and used to construct ROC curves. The area under the ROC curve was used to compare the accuracies of the indicator variables. Twenty-four-hour antecedent rainfall classified elevated Enterococcus densities more accurately than previous day's Enterococcus density (P = 0.079). An empirically derived threshold for 48-h antecedent rainfall, corresponding to a sensitivity of 0.75, was determined from the 1996 to 2000 data and evaluated to ascertain if the threshold would produce a 0.75 sensitivity with independent water quality data collected in 2001 from the same beaches.

Morrison, Ann Michelle; Coughlin, Kelly; Shine, James P.; Coull, Brent A.; Rex, Andrea C.

2003-01-01

388

A Comparison of the Physiological Condition, and Fishway Passage Time and Success of Migrant Adult Sockeye Salmon at Seton River Dam, British Columbia, under Three Operational Water Discharge Rates  

Microsoft Academic Search

We investigated the effect of changes in water discharge from the Seton River Dam, British Columbia, on the physiological condition, passage time, and passage success of adult migrant sockeye salmon Oncorhynchus nerka. Sockeye salmon were intercepted and nonlethally biopsied for blood plasma and energy status. A subset of these fish were fitted with radio transmitters and tracked under three different

L. B. Pon; S. G. Hinch; S. J. Cooke; D. A. Patterson; A. P. Farrell

2009-01-01

389

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

PubMed

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 60days prior to sampling, total precipitation 10days 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

2014-08-15

390

Water absorption characteristics and cytotoxic and biological evaluation of bone cements formulated with a novel activator.  

PubMed

A novel activator, N,N,Dimethylamino 4-benzyl laurate (DML) was used in the curing of acrylic bone cements, based on poly(methylmethacrylate). The water absorption characteristics were studied, and the behavior was found to be similar to commercial bone cements. The net amount of solubles were also in the same range as obtained for commercial cements cured with conventional activators. Biocompatibility tests were conducted on the neat activator (DML) and cured cements. The present study indicated that there were no toxic effects; furthermore, osteoblast-like cells were seen to proliferate and differentiate more readily on DML containing cements. The analysis of the effect of leachables from cements into the media showed continued cell proliferation and cell viability. PMID:10490688

Deb, S; Silvio, L D; Vazquez, B; San Roman, J

1999-01-01

391

Pressure Drop Characteristics in Tight-Lattice Bundles for Reduced-Moderation Water Reactors  

NASA Astrophysics Data System (ADS)

The reduced-moderation water reactor (RMWR) consists of several distinctive structures; a triangular tight-lattice configuration and a double-flat core. In order to design the RMWR core from the point of view of thermal-hydraulics, an evaluation method on pressure drop characteristics in the rod bundles at the tight-lattice configuration is required. In this study, calculated results by the Martinelli-Nelson's and Hancox's correlations were compared with experimental results in 4×5 rod bundles and seven-rod bundles. Consequently, the friction loss in two-phase flows becomes smaller at the tight-lattice configuration with the hydraulic diameter less than about 3mm. This reason is due to the difference of the configuration between the multi-rod bundle and the circular tube and due to the effect of the small hydraulic diameter on the two-phase multiplier.

Tamai, Hidesada; Kureta, Masatoshi; Yoshida, Hiroyuki; Akimoto, Hajime

392

The chemical/physical and microbiological characteristics of typical bath and laundry waste waters. [waste water reclamation during manned space flight  

NASA Technical Reports Server (NTRS)

Chemical/physical and microbiological characteristics are studied of typical bath and laundry waters collected during a 12 day test in which the untreated waste waters were reused for toilet flush. Most significant changes were found for ammonia, color, methylene blue active substances, phosphates, sodium, sulfates, total organic carbon, total solids, and turbidity in comparison with tap water baseline. The mean total number of microorganisms detected in the waste waters ranged from 1 million to 10 to the 7th power cells/m1 and the mean number of possible coliforms ranged from 10 to the 5th power to 1 million. An accumulation of particulates and an objectible odor were detected in the tankage used during the 12 day reuse of the untreated waste waters. The combined bath and laundry waste waters from a family of four provided 91 percent of the toilet flush water for the same family.

Hypes, W. D.; Batten, C. E.; Wilkins, J. R.

1974-01-01

393

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

394

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 con