Proline transport in Leishmania donovani amastigotes: dependence on pH gradients and membrane potential.

PubMed

Glaser, T A; Mukkada, A J

1992-03-01

Amastigotes of Leishmania donovani develop and multiply within the acidic phagolysosomes of mammalian macrophages. Isolated amastigotes are acidophilic; they catabolize substrates and synthesize macromolecules optimally at pH 5.5. Substrate transport in amastigotes has not been characterized. Here we show that amastigotes exhibit an uphill transport of proline (active transport) with an acid pH optimum (pH 5.5). It is dependent upon metabolic energy and is driven by proton motive force. Agents which selectively disturb the component forces of proton motive force, such as carbonyl cyanide chlorophenylhydrazone, nigericin and valinomycin, inhibit proline transport. Transport is sensitive to dicyclohexylcarbodiimide and insensitive to ouabain, demonstrating the involvement of a proton ATPase in the maintenance of proton motive force. It is suggested that the plasma membrane pH gradient probably makes the greatest contribution to proton motive force that drives substrate transport in the amastigote stage.

Lower limb joint angles and ground reaction forces in forefoot strike and rearfoot strike runners during overground downhill and uphill running.

PubMed

Kowalski, Erik; Li, Jing Xian

2016-11-01

This study investigated the normal and parallel ground reaction forces during downhill and uphill running in habitual forefoot strike and habitual rearfoot strike (RFS) runners. Fifteen habitual forefoot strike and 15 habitual RFS recreational male runners ran at 3 m/s ± 5% during level, uphill and downhill overground running on a ramp mounted at 6° and 9°. Results showed that forefoot strike runners had no visible impact peak in all running conditions, while the impact peaks only decreased during the uphill conditions in RFS runners. Active peaks decreased during the downhill conditions in forefoot strike runners while active loading rates increased during downhill conditions in RFS runners. Compared to the level condition, parallel braking peaks were larger during downhill conditions and parallel propulsive peaks were larger during uphill conditions. Combined with previous biomechanics studies, our findings suggest that forefoot strike running may be an effective strategy to reduce impacts, especially during downhill running. These findings may have further implications towards injury management and prevention.

Ouabain-insensitive salt and water movements in duck red cells. I. Kinetics of cation transport under hypertonic conditions

PubMed Central

Schmidt III, WF; McManus, TJ

1977-01-01

Duck red cells in hypertonic media experience rapid osmotic shrinkage followed by gradual reswelling back toward their original volume. This uptake of salt and water is self limiting and demands a specific ionic composition of the external solution. Although ouabain (10(-4)M) alters the pattern of cation accumulation from predominantly potassium to sodium, it does not affect the rate of the reaction, or the total amount of salt or water taken up. To study the response without the complications of active Na-K transport, ouabain was added to most incubations. All water accumulated by the cells can be accounted for by net salt uptake. Specific external cation requirements for reswelling include: sufficient sodium (more than 23 mM), and elevated potassium (more than 7 mM). In the absence of external potassium cells lose potassium without gaining sodium and continue to shrink instead of reswelling. Adding rubidium to the potassium- free solution promotes an even greater loss of cell potassium, yet causes swelling due to a net uptake of sodium and rubidium followed by chloride. The diuretic furosemide (10(-3)M) inhibits net sodium uptake which depends on potassium (or rubidium), as well as inhibits net sodium uptake which depends on sodium. As a result, cell volume is stabilized in the presence of this drug by inhibition of shrinkage, at low, and of swelling at high external potassium. The response has a high apparent energy of activation (15-20 kcal/mol). We propose that net salt and water movements in hypertonic solutions containing ouabain are mediated by direct coupling or cis-interaction, between sodium and potassium so that the uphill movement of one is driven by the downhill movement of the other in the same direction. PMID:894251

How Arch Support Insoles Help Persons with Flatfoot on Uphill and Downhill Walking.

PubMed

Huang, Yu-Ping; Kim, Kwantae; Song, Chen-Yi; Chen, Yat-Hon; Peng, Hsien-Te

2017-01-01

The main purpose of this study was to investigate the effect of arch support insoles on uphill and downhill walking of persons with flatfoot. Sixteen healthy college students with flatfoot were recruited in this study. Their heart rate, peak oxygen uptake (VO 2 ), and median frequency (MDF) of surface electromyogram were recorded and analyzed. Nonparametric Wilcoxon signed-rank test was used for statistical analysis. The main results were as follows: (a) peak VO 2 significantly decreased with arch support insoles compared with flat insoles during uphill and downhill walking (arch support insole versus flat insole: uphill walking, 20.7 ± 3.6 versus 31.6 ± 5.5; downhill walking, 10.9 ± 2.3 versus 16.9 ± 4.2); (b) arch support insoles could reduce the fatigue of the rectus femoris muscle during downhill walking (MDF slope of arch support insole: 0.03 ± 1.17, flat insole: -6.56 ± 23.07); (c) insole hardness would increase not only the physical sensory input but also the fatigue of lower-limb muscles particularly for the rectus femoris muscle (MDF slope of arch support insole: -1.90 ± 1.60, flat insole: -0.83 ± 1.10) in persons with flatfoot during uphill walking. The research results show that arch support insoles could effectively be applied to persons with flatfoot to aid them during uphill and downhill walking.

Influence of the world's most challenging mountain ultra-marathon on energy cost and running mechanics.

PubMed

Vernillo, Gianluca; Savoldelli, Aldo; Zignoli, Andrea; Trabucchi, Pietro; Pellegrini, Barbara; Millet, Grégoire P; Schena, Federico

2014-05-01

To examine the effects of the world's most challenging mountain ultra-marathon (Tor des Géants(®) 2012) on the energy cost of three types of locomotion (cycling, level and uphill running) and running kinematics. Before (pre-) and immediately after (post-) the competition, a group of ten male experienced ultra-marathon runners performed in random order three submaximal 4-min exercise trials: cycling at a power of 1.5 W kg(-1) body mass; level running at 9 km h(-1) and uphill running at 6 km h(-1) at an inclination of +15 % on a motorized treadmill. Two video cameras recorded running mechanics at different sampling rates. Between pre- and post-, the uphill-running energy cost decreased by 13.8 % (P = 0.004); no change was noted in the energy cost of level running or cycling (NS). There was an increase in contact time (+10.3 %, P = 0.019) and duty factor (+8.1 %, P = 0.001) and a decrease in swing time (-6.4 %, P = 0.008) in the uphill-running condition. After this extreme mountain ultra-marathon, the subjects modified only their uphill-running patterns for a more economical step mechanics.

Concentric and eccentric exercise, glycemic responses to a postexercise meal, and inflammation in women with high versus low waist circumference.

PubMed

Miles, Mary P; Horrigan, Laura C; Jay, Sara E; Brown, Karen M; Porter, Jay W; Steward, Andrea N

2016-12-01

Carbohydrate ingestion and level of concentric versus eccentric muscle activity may alter exercise-induced health benefits for individuals who have high waist circumference as a metabolic risk factor. The purpose of this study was to determine whether metabolic and inflammation responses to an exercise recovery meal differ between women with lower (Lo-WC, <80 cm) compared with higher (Hi-WC) waist circumference when the exercise is primarily concentric (uphill walking; UPHILL) versus primarily eccentric (downhill walking; DOWNHILL). Recreationally active women (age, 18-39 years; body mass index, 19-35.4 m·kg -2 ; Lo-WC, n = 13; Hi-WC, n = 10) completed UPHILL, DOWNHILL, and resting (CONTROL) conditions followed 30 min later by a mixed meal tolerance test (MMTT) with carbohydrates to protein ratio of 4:1, and blood glucose, insulin, and inflammation markers were compared across conditions. Compared with Lo-WC, the Hi-WC group had higher (p < 0.05) (i) insulin during the MMTT in CONTROL (mean ± SE; 48.5 ± 8.2 vs 22.9 ± 2.8 pmol·L -1 ), (ii) baseline (0.7 ± 0.4 vs 2.0 ± 1.7 pg·mL -1 ) interleukin-6 (IL-6), and (iii) IL-6 responses 8 h after UPHILL and CONTROL. Both groups had (i) increases in IL-6 at 0 h after UPHILL and at 8 h after DOWNHILL, and (ii) lower glycemic responses in UPHILL. Women with Hi-WC had higher IL-6 at rest and delayed increases in IL-6 after a high-carbohydrate meal in all conditions. This is consistent with an inflammation response to the meal and or uphill walking exercise. However, both concentrically and eccentrically biased exercises offered benefits to insulin responses to a high carbohydrate meal for Hi-WC.

Does apical membrane GLUT2 have a role in intestinal glucose uptake?

PubMed

Naftalin, Richard J

2014-01-01

It has been proposed that the non-saturable component of intestinal glucose absorption, apparent following prolonged exposure to high intraluminal glucose concentrations, is mediated via the low affinity glucose and fructose transporter, GLUT2, upregulated within the small intestinal apical border. The evidence that the non-saturable transport component is mediated via an apical membrane sugar transporter is that it is inhibited by phloretin, after exposure to phloridzin. Since the other apical membrane sugar transporter, GLUT5, is insensitive to inhibition by either cytochalasin B, or phloretin, GLUT2 was deduced to be the low affinity sugar transport route. As in its uninhibited state, polarized intestinal glucose absorption depends both on coupled entry of glucose and sodium across the brush border membrane and on the enterocyte cytosolic glucose concentration exceeding that in both luminal and submucosal interstitial fluids, upregulation of GLUT2 within the intestinal brush border will usually stimulate downhill glucose reflux to the intestinal lumen from the enterocytes; thereby reducing, rather than enhancing net glucose absorption across the luminal surface. These states are simulated with a computer model generating solutions to the differential equations for glucose, Na and water flows between luminal, cell, interstitial and capillary compartments. The model demonstrates that uphill glucose transport via SGLT1 into enterocytes, when short-circuited by any passive glucose carrier in the apical membrane, such as GLUT2, will reduce transcellular glucose absorption and thereby lead to increased paracellular flow. The model also illustrates that apical GLUT2 may usefully act as an osmoregulator to prevent excessive enterocyte volume change with altered luminal glucose concentrations.

Does apical membrane GLUT2 have a role in intestinal glucose uptake?

PubMed Central

Naftalin, Richard J

2014-01-01

It has been proposed that the non-saturable component of intestinal glucose absorption, apparent following prolonged exposure to high intraluminal glucose concentrations, is mediated via the low affinity glucose and fructose transporter, GLUT2, upregulated within the small intestinal apical border. The evidence that the non-saturable transport component is mediated via an apical membrane sugar transporter is that it is inhibited by phloretin, after exposure to phloridzin. Since the other apical membrane sugar transporter, GLUT5, is insensitive to inhibition by either cytochalasin B, or phloretin, GLUT2 was deduced to be the low affinity sugar transport route. As in its uninhibited state, polarized intestinal glucose absorption depends both on coupled entry of glucose and sodium across the brush border membrane and on the enterocyte cytosolic glucose concentration exceeding that in both luminal and submucosal interstitial fluids, upregulation of GLUT2 within the intestinal brush border will usually stimulate downhill glucose reflux to the intestinal lumen from the enterocytes; thereby reducing, rather than enhancing net glucose absorption across the luminal surface. These states are simulated with a computer model generating solutions to the differential equations for glucose, Na and water flows between luminal, cell, interstitial and capillary compartments. The model demonstrates that uphill glucose transport via SGLT1 into enterocytes, when short-circuited by any passive glucose carrier in the apical membrane, such as GLUT2, will reduce transcellular glucose absorption and thereby lead to increased paracellular flow. The model also illustrates that apical GLUT2 may usefully act as an osmoregulator to prevent excessive enterocyte volume change with altered luminal glucose concentrations. PMID:25671087

Fatigue associated with prolonged graded running.

PubMed

Giandolini, Marlene; Vernillo, Gianluca; Samozino, Pierre; Horvais, Nicolas; Edwards, W Brent; Morin, Jean-Benoît; Millet, Guillaume Y

2016-10-01

Scientific experiments on running mainly consider level running. However, the magnitude and etiology of fatigue depend on the exercise under consideration, particularly the predominant type of contraction, which differs between level, uphill, and downhill running. The purpose of this review is to comprehensively summarize the neurophysiological and biomechanical changes due to fatigue in graded running. When comparing prolonged hilly running (i.e., a combination of uphill and downhill running) to level running, it is found that (1) the general shape of the neuromuscular fatigue-exercise duration curve as well as the etiology of fatigue in knee extensor and plantar flexor muscles are similar and (2) the biomechanical consequences are also relatively comparable, suggesting that duration rather than elevation changes affects neuromuscular function and running patterns. However, 'pure' uphill or downhill running has several fatigue-related intrinsic features compared with the level running. Downhill running induces severe lower limb tissue damage, indirectly evidenced by massive increases in plasma creatine kinase/myoglobin concentration or inflammatory markers. In addition, low-frequency fatigue (i.e., excitation-contraction coupling failure) is systematically observed after downhill running, although it has also been found in high-intensity uphill running for different reasons. Indeed, low-frequency fatigue in downhill running is attributed to mechanical stress at the interface sarcoplasmic reticulum/T-tubule, while the inorganic phosphate accumulation probably plays a central role in intense uphill running. Other fatigue-related specificities of graded running such as strategies to minimize the deleterious effects of downhill running on muscle function, the difference of energy cost versus heat storage or muscle activity changes in downhill, level, and uphill running are also discussed.

Streaks on Opportunity Solar Panel After Uphill Drive

NASA Image and Video Library

2016-03-31

This image from the navigation camera on the mast of NASA Mars Exploration Rover Opportunity shows streaks of dust or sand on the vehicle rear solar panel after a series of drives during which the rover was pointed steeply uphill.

Heart rate profiles and energy cost of locomotion during cross-country skiing races.

PubMed

Mognoni, P; Rossi, G; Gastaldelli, F; Canclini, A; Cotelli, F

2001-07-01

The purpose of this study was to compare heart rate responses and speed in two cross-country skiing races, which were run by seven male and seven female subjects by using classic and free style. Heart rates and skiing velocities were analyzed over flat, uphill and downhill sections, which were run from one to three times. Heart rates were higher in uphill sections than in flat sections; a steady-state heart rate was never reached in the downhill section. When the same uphill section was repeated, the heart rate tended to increase but the speed to decrease. Oxygen uptake (VO2) was calculated from heart rate:VO2 ratio, measured during uphill walking with the aid of poles. The mean (SD) energy cost of locomotion (i.e., the ratio between net VO2 and speed) was 162.1 (9.4) ml.km(-1).kg(-1) and 147.7 (7.1) ml.km(-1).kg(-1) when male subjects ran the flat section after first downhill by using classic and free style, respectively. Females had lower values for VO2 and speed, but similar energy costs. In general, the variability of the energy cost of locomotion in skiers of a similar competitive level is of the same order as that found in uphill walking on a treadmill.

DE LAVAUD CHARGING FROM WEST (UPHILL), TREATING LANCE WITH CALCIUM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DE LAVAUD CHARGING FROM WEST (UPHILL), TREATING LANCE WITH CALCIUM CARBONATE IN CENTER & CASTING PIPE TO THE RIGHT. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

Analysis of Classical Time-Trial Performance and Technique-Specific Physiological Determinants in Elite Female Cross-Country Skiers.

PubMed

Sandbakk, Øyvind; Losnegard, Thomas; Skattebo, Øyvind; Hegge, Ann M; Tønnessen, Espen; Kocbach, Jan

2016-01-01

The present study investigated the contribution of performance on uphill, flat, and downhill sections to overall performance in an international 10-km classical time-trial in elite female cross-country skiers, as well as the relationships between performance on snow and laboratory-measured physiological variables in the double poling (DP) and diagonal (DIA) techniques. Ten elite female cross-country skiers were continuously measured by a global positioning system device during an international 10-km cross-country skiing time-trial in the classical technique. One month prior to the race, all skiers performed a 5-min submaximal and 3-min self-paced performance test while roller skiing on a treadmill, both in the DP and DIA techniques. The time spent on uphill (r = 0.98) and flat (r = 0.91) sections of the race correlated most strongly with the overall 10-km performance (both p < 0.05). Approximately 56% of the racing time was spent uphill, and stepwise multiple regression revealed that uphill time explained 95.5% of the variance in overall performance (p < 0.001). Distance covered during the 3-min roller-skiing test and body-mass normalized peak oxygen uptake (VO2peak) in both techniques showed the strongest correlations with overall time-trial performance (r = 0.66-0.78), with DP capacity tending to have greatest impact on the flat and DIA capacity on uphill terrain (all p < 0.05). Our present findings reveal that the time spent uphill most strongly determine classical time-trial performance, and that the major portion of the performance differences among elite female cross-country skiers can be explained by variations in technique-specific aerobic power.

Analysis of Classical Time-Trial Performance and Technique-Specific Physiological Determinants in Elite Female Cross-Country Skiers

PubMed Central

Sandbakk, Øyvind; Losnegard, Thomas; Skattebo, Øyvind; Hegge, Ann M.; Tønnessen, Espen; Kocbach, Jan

2016-01-01

The present study investigated the contribution of performance on uphill, flat, and downhill sections to overall performance in an international 10-km classical time-trial in elite female cross-country skiers, as well as the relationships between performance on snow and laboratory-measured physiological variables in the double poling (DP) and diagonal (DIA) techniques. Ten elite female cross-country skiers were continuously measured by a global positioning system device during an international 10-km cross-country skiing time-trial in the classical technique. One month prior to the race, all skiers performed a 5-min submaximal and 3-min self-paced performance test while roller skiing on a treadmill, both in the DP and DIA techniques. The time spent on uphill (r = 0.98) and flat (r = 0.91) sections of the race correlated most strongly with the overall 10-km performance (both p < 0.05). Approximately 56% of the racing time was spent uphill, and stepwise multiple regression revealed that uphill time explained 95.5% of the variance in overall performance (p < 0.001). Distance covered during the 3-min roller-skiing test and body-mass normalized peak oxygen uptake (VO2peak) in both techniques showed the strongest correlations with overall time-trial performance (r = 0.66–0.78), with DP capacity tending to have greatest impact on the flat and DIA capacity on uphill terrain (all p < 0.05). Our present findings reveal that the time spent uphill most strongly determine classical time-trial performance, and that the major portion of the performance differences among elite female cross-country skiers can be explained by variations in technique-specific aerobic power. PMID:27536245

A Puzzle in Elementary Ballistics.

ERIC Educational Resources Information Center

Haugland, Ole Anton

1983-01-01

Provides an answer to the question of why it is easy to miss when shooting uphill or downhill. Experimental results indicate that when shooting uphill or downhill, sight should not be adjusted to actual distance but to distance multiplied by the cosine of the inclination angle. (JN)

Quantifying the total cost of infrastructure to enable environmentally preferable decisions: the case of urban roadway design

NASA Astrophysics Data System (ADS)

Gosse, Conrad A.; Clarens, Andres F.

2013-03-01

Efforts to reduce the environmental impacts of transportation infrastructure have generally overlooked many of the efficiencies that can be obtained by considering the relevant engineering and economic aspects as a system. Here, we present a framework for quantifying the burdens of ground transportation in urban settings that incorporates travel time, vehicle fuel and pavement maintenance costs. A Pareto set of bi-directional lane configurations for two-lane roadways yields non-dominated combinations of lane width, bicycle lanes and curb parking. Probabilistic analysis and microsimulation both show dramatic mobility reductions on road segments of insufficient width for heavy vehicles to pass bicycles without encroaching on oncoming traffic. This delay is positively correlated with uphill grades and increasing traffic volumes and inversely proportional to total pavement width. The response is nonlinear with grade and yields mixed uphill/downhill optimal lane configurations. Increasing bicycle mode share is negatively correlated with total costs and emissions for lane configurations allowing motor vehicles to safely pass bicycles, while the opposite is true for configurations that fail to facilitate passing. Spatial impacts on mobility also dictate that curb parking exhibits significant spatial opportunity costs related to the total cost Pareto curve. The proposed framework provides a means to evaluate relatively inexpensive lane reconfiguration options in response to changing modal share and priorities. These results provide quantitative evidence that efforts to reallocate limited pavement space to bicycles, like those being adopted in several US cities, could appreciably reduce costs for all users.

Impact of Incline, Sex and Level of Performance on Kinematics During a Distance Race in Classical Cross-Country Skiing.

PubMed

Stöggl, Thomas; Welde, Boye; Supej, Matej; Zoppirolli, Chiara; Rolland, Carsten G; Holmberg, Hans-Christer; Pellegrini, Barbara

2018-03-01

Here, female and male elite cross-country (XC) skiers were compared on varying terrain during an official 10-km (women) and 15-km (men) Norwegian championship race. On the basis of race performance, 82 skiers were classified as fast (FS) (20 women, 20 men) or slower (SS) (21, 21) skiers. All were video recorded on flat (0°), intermediate (3.5°), uphill (7.1°) and steep uphill (11°) terrain during the race at a distance of 0.8, 1.2, 2.1 and 7.1 km from the start, respectively. All skiers employed exclusively double-poling (DP) on the flat section and, except for the male winner, exclusively diagonal stride (DIA) on the uphill sections. On the intermediate section, more men than women utilized DP and fewer DIA (p = 0.001), with no difference in kick double-poling (DPK). More FS than SS utilized DPK and fewer DIA (p = 0.001), with similar usage of DP. Males skied with faster and longer cycles but lower cycle rate compared with females (p < 0.001), with largest absolute sex differences on flat terrain (p < 0.001) and largest relative differences for cycle velocity and length on intermediate and uphill terrain. External power output rose with increasing incline, being higher for men and FS (p < 0.001). Cycle velocity on flat terrain was the best predictor of mean race velocity for the men, while cycle velocity on steep uphill was the best predictor for the women (both p < 0.001). In conclusion, incline, sex and level of performance influenced cycle characteristics and power output. Greatest absolute sex gap was on flat terrain, whereas the relative difference was greatest on intermediate and steep uphill terrain. We recommend usage of more DP and/or DPK, and less DIA and fewer transitions between techniques on intermediate terrain. Predictors of race performance are sex specific with greatest potential for enhancing performance on flat terrain for men and on steep uphill terrain for women.

Uncoupling and Turnover in a Cl−/H+ Exchange Transporter

PubMed Central

Walden, Michael; Accardi, Alessio; Wu, Fang; Xu, Chen; Williams, Carole; Miller, Christopher

2007-01-01

The CLC-family protein CLC-ec1, a bacterial homologue of known structure, stoichiometrically exchanges two Cl− for one H+ via an unknown membrane transport mechanism. This study examines mutations at a conserved tyrosine residue, Y445, that directly coordinates a Cl− ion located near the center of the membrane. Mutations at this position lead to “uncoupling,” such that the H+/Cl− transport ratio decreases roughly with the volume of the substituted side chain. The uncoupled proteins are still able to pump protons uphill when driven by a Cl− gradient, but the extent and rate of this H+ pumping is weaker in the more uncoupled variants. Uncoupling is accompanied by conductive Cl− transport that is not linked to counter-movement of H+, i.e., a “leak.” The unitary Cl− transport rate, measured in reconstituted liposomes by both a conventional initial-velocity method and a novel Poisson dilution approach, is ∼4,000 s−1 for wild-type protein, and the uncoupled mutants transport Cl− at similar rates. PMID:17389248

Impact of Incline, Sex and Level of Performance on Kinematics During a Distance Race in Classical Cross-Country Skiing

PubMed Central

Stöggl, Thomas; Welde, Boye; Supej, Matej; Zoppirolli, Chiara; Rolland, Carsten G.; Holmberg, Hans-Christer; Pellegrini, Barbara

2018-01-01

Here, female and male elite cross-country (XC) skiers were compared on varying terrain during an official 10-km (women) and 15-km (men) Norwegian championship race. On the basis of race performance, 82 skiers were classified as fast (FS) (20 women, 20 men) or slower (SS) (21, 21) skiers. All were video recorded on flat (0°), intermediate (3.5°), uphill (7.1°) and steep uphill (11°) terrain during the race at a distance of 0.8, 1.2, 2.1 and 7.1 km from the start, respectively. All skiers employed exclusively double-poling (DP) on the flat section and, except for the male winner, exclusively diagonal stride (DIA) on the uphill sections. On the intermediate section, more men than women utilized DP and fewer DIA (p = 0.001), with no difference in kick double-poling (DPK). More FS than SS utilized DPK and fewer DIA (p = 0.001), with similar usage of DP. Males skied with faster and longer cycles but lower cycle rate compared with females (p < 0.001), with largest absolute sex differences on flat terrain (p < 0.001) and largest relative differences for cycle velocity and length on intermediate and uphill terrain. External power output rose with increasing incline, being higher for men and FS (p < 0.001). Cycle velocity on flat terrain was the best predictor of mean race velocity for the men, while cycle velocity on steep uphill was the best predictor for the women (both p < 0.001). In conclusion, incline, sex and level of performance influenced cycle characteristics and power output. Greatest absolute sex gap was on flat terrain, whereas the relative difference was greatest on intermediate and steep uphill terrain. We recommend usage of more DP and/or DPK, and less DIA and fewer transitions between techniques on intermediate terrain. Predictors of race performance are sex specific with greatest potential for enhancing performance on flat terrain for men and on steep uphill terrain for women. Key points There was a main effect of sex and level of performance, with longer and more rapid cycles by male than female skiers and by faster than slower skiers. The largest absolute sex differences in cycle velocity and length were observed on flat terrain, with these differences narrowing as the incline rose. However, the greatest relative sex differences were in cycle velocity on the intermediate terrain (23.3%) and for cycle length on steep uphill terrain (27.0%). The men employed DP and DPK to a greater extent and with fewer transitions on intermediate terrain than the women. Faster skiers (especially women) employed DPK to a greater and DIA to a lesser extent than the slower skiers, with approximately equal usage of DP. Cycle velocity on flat terrain was the best predictor of mean race velocity for the men, while cycle velocity on steep uphill terrain was the best predictor in the case of the women. As the incline increased, cycle velocity, cycle length and pole swing time were reduced, while poling time and external power output rose. A J-shaped pattern with respect to cycle rate was observed, with the lowest values on intermediate and highest on steep uphill terrain. PMID:29535586

Energetics and biomechanics of locomotion by red kangaroos (Macropus rufus).

PubMed

Kram, R; Dawson, T J

1998-05-01

As red kangaroos hop faster over level ground, their rate of oxygen consumption (indicating metabolic energy consumption) remains nearly the same. This phenomenon has been attributed to exceptional elastic energy storage and recovery via long compliant tendons in the legs. Alternatively, red kangaroos may have exceptionally efficient muscles. To estimate efficiency, we measured the metabolic cost of uphill hopping, where muscle fibers must perform mechanical work against gravity. We found that uphill hopping was much more expensive than level hopping. The maximal rate of oxygen consumption measured (3 ml O2 kg-1 s-1) exceeds all but a few vertebrate species. However, efficiency values were normal, approximately 30%. At faster level hopping speeds the effective mechanical advantage of the extensor muscles of the ankle joint remained the same. Thus, kangaroos generate the same muscular force at all speeds but do so more rapidly at faster hopping speeds. This contradicts a recent hypothesis for what sets the cost of locomotion. The cost of transport (J kg-1 m-1) decreases at faster hopping speeds, yet red kangaroos prefer to use relatively slow speeds that avoid high levels of tendon stress.

Progress toward an explicit mechanistic model for the light-driven pump, bacteriorhodopsin

NASA Technical Reports Server (NTRS)

Lanyi, J. K.

1999-01-01

Recent crystallographic information about the structure of bacteriorhodopsin and some of its photointermediates, together with a large amount of spectroscopic and mutational data, suggest a mechanistic model for how this protein couples light energy to the translocation of protons across the membrane. Now nearing completion, this detailed molecular model will describe the nature of the steric and electrostatic conflicts at the photoisomerized retinal, as well as the means by which it induces proton transfers in the two half-channels leading to the two membrane surfaces, thereby causing unidirectional, uphill transport.

Mechanical Paradox: The Uphill Roller

ERIC Educational Resources Information Center

Cortes, Emilio; Cortes-Poza, D.

2011-01-01

We analyse in detail the dynamics of a mechanical system which is a rigid body with the geometry of a double cone. This double cone is apparently able to spontaneously roll uphill along inclined rails. The experiment has been known for some centuries, and because of its peculiar behaviour, it has been named "mechanical paradox". Although this…

Nonequilibrium two-dimensional Ising model with stationary uphill diffusion.

PubMed

Colangeli, Matteo; Giardinà, Cristian; Giberti, Claudio; Vernia, Cecilia

2018-03-01

Usually, in a nonequilibrium setting, a current brings mass from the highest density regions to the lowest density ones. Although rare, the opposite phenomenon (known as "uphill diffusion") has also been observed in multicomponent systems, where it appears as an artificial effect of the interaction among components. We show here that uphill diffusion can be a substantial effect, i.e., it may occur even in single component systems as a consequence of some external work. To this aim we consider the two-dimensional ferromagnetic Ising model in contact with two reservoirs that fix, at the left and the right boundaries, magnetizations of the same magnitude but of opposite signs.We provide numerical evidence that a class of nonequilibrium steady states exists in which, by tuning the reservoir magnetizations, the current in the system changes from "downhill" to "uphill". Moreover, we also show that, in such nonequilibrium setup, the current vanishes when the reservoir magnetization attains a value approaching, in the large volume limit, the magnetization of the equilibrium dynamics, thus establishing a relation between equilibrium and nonequilibrium properties.

Nonequilibrium two-dimensional Ising model with stationary uphill diffusion

NASA Astrophysics Data System (ADS)

Colangeli, Matteo; Giardinà, Cristian; Giberti, Claudio; Vernia, Cecilia

2018-03-01

Usually, in a nonequilibrium setting, a current brings mass from the highest density regions to the lowest density ones. Although rare, the opposite phenomenon (known as "uphill diffusion") has also been observed in multicomponent systems, where it appears as an artificial effect of the interaction among components. We show here that uphill diffusion can be a substantial effect, i.e., it may occur even in single component systems as a consequence of some external work. To this aim we consider the two-dimensional ferromagnetic Ising model in contact with two reservoirs that fix, at the left and the right boundaries, magnetizations of the same magnitude but of opposite signs.We provide numerical evidence that a class of nonequilibrium steady states exists in which, by tuning the reservoir magnetizations, the current in the system changes from "downhill" to "uphill". Moreover, we also show that, in such nonequilibrium setup, the current vanishes when the reservoir magnetization attains a value approaching, in the large volume limit, the magnetization of the equilibrium dynamics, thus establishing a relation between equilibrium and nonequilibrium properties.

Measuring Cycling Effort.

ERIC Educational Resources Information Center

Jahnke, Thomas; Hamson, Mike

1999-01-01

Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

Uphill and Downhill in a Flat World: The Conceptual Topography of the Yupno House

ERIC Educational Resources Information Center

Cooperrider, Kensy; Slotta, James; Núñez, Rafael

2017-01-01

Speakers of many languages around the world rely on body-based contrasts (e.g., "left/right") for spatial communication and cognition. Speakers of Yupno, a language of Papua New Guinea's mountainous interior, rely instead on an environment-based "uphill/downhill" contrast. Body-based contrasts are as easy to use indoors as…

Investigation of nitrogen transport in active screen plasma nitriding processes - Uphill diffusion effect

NASA Astrophysics Data System (ADS)

Jasinski, J. J.; Fraczek, T.; Kurpaska, L.; Lubas, M.; Sitarz, M.

2018-07-01

The paper presents a structure of a nitrided layer formed with active screen plasma nitriding (ASPN) technique, which is a modification of plasma nitriding. The model investigated material was Fe Armco. The nitriding processes were carried out at 773 K for 6 h and 150 Pa. The main objective of this study was to confirm nitrogen migration effect and its influence on the nitride layer formation in different area of the layer interfaces (ε/ε+γ‧/γ‧). The results of the tests were evaluated using scanning electron microscopy (SEM, SEM/EBSD), transmission electron microscopy - electron energy loss spectroscopy (TEM-EFTEM), secondary ion mass spectroscopy (SIMS) and Wavelength Dispersive X-Ray Spectrometry (WDS). The analysis of the results suggests that the structures of the nitrided layers and nitrides morphology differ for various parameters and are dependent on the surface layer saturation mechanism for each of the temperatures and process parameters. New approaches in diffusion of nitrogen and carbon atoms and optimizing process were also analyzed. Nitrogen and also carbon transport in the sublayer was observed by several effects i.e. uphill diffusion effect which confirmed migration of the atoms in diffusive layer towards top surface (ε/ε+γ‧ interface) and stress change effect in the nitrogen saturation area of the (Fe(C,N)+γ‧) layer. Results showed in the paper might be used both for optimization of ASPN processes, modeling of nitrided layers formation mechanism and for controlling the nitrided layers morphology when nitriding different Fe based materials.

Utilizing Tritium and CFC-12 to Determine Groundwater Sources in an Unconfined Aquifer Within the Abalone Cove Landslide, Palos Verdes, California

NASA Astrophysics Data System (ADS)

Difilippo, E. L.; Hammond, D. E.; Douglas, R.; Clark, J. F.; Avisar, D.; Dunker, R.

2004-12-01

The Abalone Cove landslide occupies 80 acres of an ancient landslide complex on the Palos Verdes peninsula, and was re-activated in 1979. The uphill portion of the ancient landslide complex has remained stable in historic times. Water infiltration into the slide is a short term catalyst for mass movement in the area, so it is important to determine the sources of groundwater throughout the slide mass. Water may enter the slide mass through direct percolation of recent precipitation, inflow along the head scarp of the ancient landslide or by rising through the slide plane from a deeper aquifer. The objective of this contribution is to use geochemical tracers (tritium and CFC-12) in combination with numerical modeling to constrain the importance of each of these sources. Numerical models were constructed to predict geochemical tracer concentrations throughout the basin, assuming that the only source of water to the slide mass is percolation of recent precipitation. Predicted concentrations were then compared to measured tracer values. In the ancient landslide, predicted and measured tracer concentrations are in good agreement, indicating that most of the water in this area is recent precipitation falling within the basin. Groundwater recharged uphill of the ancient landslide contributes minor flow into the complex through the head scarp, with the majority of this water flowing beneath the ancient slide plane. However, predicted tracer concentrations in the toe of the Abalone Cove landslide are not consistent with measured values. Both CFC-12 and tritium concentrations indicate that water is older than predicted and communication between the slide mass and the aquifer beneath the slide plane must occur in this area. Infiltration of this deep circulating water may exert upward hydraulic pressure on the landslide slip surface, increasing the potential for movement. This hypothesis is consistent with the observation that current movement is only occurring in the area in which tracers indicate communication with the deeper aquifer.

Effect of Divalent Cations on RED Performance and Cation Exchange Membrane Selection to Enhance Power Densities.

PubMed

Rijnaarts, Timon; Huerta, Elisa; van Baak, Willem; Nijmeijer, Kitty

2017-11-07

Reverse electrodialysis (RED) is a membrane-based renewable energy technology that can harvest energy from salinity gradients. The anticipated feed streams are natural river and seawater, both of which contain not only monovalent ions but also divalent ions. However, RED using feed streams containing divalent ions experiences lower power densities because of both uphill transport and increased membrane resistance. In this study, we investigate the effects of divalent cations (Mg 2+ and Ca 2+ ) on RED and demonstrate the mitigation of those effects using both novel and existing commercial cation exchange membranes (CEMs). Monovalent-selective Neosepta CMS is known to block divalent cations transport and can therefore mitigate reductions in stack voltage. The new multivalent-permeable Fuji T1 is able to transport divalent cations without a major increase in resistance. Both strategies significantly improve power densities compared to standard-grade CEMs when performing RED using streams containing divalent cations.

Speed and heart-rate profiles in skating and classical cross-country skiing competitions.

PubMed

Bolger, Conor M; Kocbach, Jan; Hegge, Ann Magdalen; Sandbakk, Øyvind

2015-10-01

To compare the speed and heart-rate profiles during international skating and classical competitions in male and female world-class cross-country skiers. Four male and 5 female skiers performed individual time trials of 15 km (men) and 10 km (women) in the skating and classical techniques on 2 consecutive days. Races were performed on the same 5-km course. The course was mapped with GPS and a barometer to provide a valid course and elevation profile. Time, speed, and heart rate were determined for uphill, flat, and downhill terrains throughout the entire competition by wearing a GPS and a heart-rate monitor. Times in uphill, flat, and downhill terrain were ~55%, 15-20%, and 25-30%, respectively, of the total race time for both techniques and genders. The average speed differences between skating and classical skiing were 9% and 11% for men and women, respectively, and these values were 12% and 15% for uphill, 8% and 13% for flat (all P < .05), and 2% and 1% for downhill terrain. The average speeds for men were 9% and 11% faster than for women in skating and classical, respectively, with corresponding numbers of 11% and 14% for uphill, 6% and 11% for flat, and 4% and 5% for downhill terrain (all P < .05). Heart-rate profiles were relatively independent of technique and gender. The greatest performance differences between the skating and classical techniques and between the 2 genders were found on uphill terrain. Therefore, these speed differences could not be explained by variations in exercise intensity.

Uphill walking with a simple exoskeleton: plantarflexion assistance leads to proximal adaptations.

PubMed

Galle, S; Malcolm, P; Derave, W; De Clercq, D

2015-01-01

While level walking with a pneumatic ankle-foot exoskeleton is studied extensively, less is known on uphill walking. The goals of this study were to get a better understanding of the biomechanical adaptations and the influence of actuation timing on metabolic cost during uphill walking with a plantarflexion assisting exoskeleton. Seven female subjects walked on a treadmill with 15% inclination at 1.36 ms(-1) in five conditions (4 min): one condition with an unpowered exoskeleton and four with a powered exoskeleton with onset of pneumatic muscle actuation at 19, 26, 34 and 41% of stride. During uphill walking the metabolic cost was more than 10% lower for all powered conditions compared to the unpowered condition. When actuation onset was in between 26 and 34% of the stride, metabolic cost was suggested to be minimal. While it was expected that exoskeleton assistance would reduce muscular activity of the plantarflexors during push-off, subjects used the additional power to raise the body centre of mass in the beginning of each step to a higher point compared to unpowered walking. This reduced the muscular activity in the m. vastus lateralis and the m. biceps femoris as less effort was necessary to reach the highest body centre of mass position in the single support phase. In conclusion, subjects can use plantarflexion assistance during the push-off to reduce muscular activity in more proximal joints in order to minimize energy cost during uphill locomotion. Kinetic data seem necessary to fully understand this mechanism, which highlights the complexity of human-exoskeleton interaction. Copyright © 2014 Elsevier B.V. All rights reserved.

Electroneutral, HCO3(-)-independent, pH gradient-dependent uphill transport of Cl- by ileal brush-border membrane vesicles. Possible role in the pathogenesis of chloridorrhea.

PubMed Central

Vasseur, M; Caüzac, M; Alvarado, F

1989-01-01

By applying a rapid filtration technique to isolated brush border membrane vesicles from guinea pig ileum, 36Cl uptake was quantified in the presence and absence of electrical, pH and alkali-metal ion gradients. A mixture of 20 mM-Hepes and 40 mM-citric acid, adjusted to the desired pH with Tris base, was found to be the most suitable buffer. Malate and Mes could be used to replace the citrate, but succinate, acetate and maleate proved to be unsuitable. In the absence of a pH gradient (pHout:pHin = 7.5:7.5), Cl- uptake increased slightly when an inside-positive membrane potential was applied, but uphill transport was never observed. A pH gradient (pHout:pHin = 5.0:7.5) induced both a 400% increase in the initial Cl- influx rate and a long-lasting (20 to 300 s) overshoot, indicating that a proton gradient can furnish the driving force for uphill Cl- transport. Under pH gradient conditions, initial Cl- entry rates had the following characteristics. (1) They were unaffected by cis-Na+ and/or -K+, indicating the absence of Cl-/K+, Cl-/Na+ or Cl-/K+/Na+ symport activity. (2) Inhibition by 20-100 mM-trans-Na+ and/or -K+ occurred, independent of the existence of an ion gradient. (3) Cl- entry was practically unaffected by short-circuiting the membrane potential with equilibrated potassium and valinomycin. (4) Carbonyl cyanide m-chlorophenylhydrazone was strongly inhibitory and so, to a lesser extent, was 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid [(SITS)], independent of the sign and size of the membrane potential. (5) Cl- entry was negligibly increased (less than 30%) by either trans-Cl- or -HCO3-, indicating the absence of an obligatory Cl-/anion antiport activity. In contrast, the height of the overshoot at 60 s was increased by trans-Cl-, indicating time-dependent inhibition of 36Cl efflux. That competitive inhibition of 36Cl fluxes by anions is involved here is supported by initial influx rate experiments demonstrating: (1) the saturability of Cl- influx, which was found to exhibit Michaelis-Menten kinetics; and (2) competitive inhibition of influx by cis-Cl- and -Br-. Quantitatively, the conclusion is warranted that over 85% of the total initial Cl- uptake energized by a pH gradient involves an electroneutral Cl-/H+ symporter or its physicochemical equivalent, a Cl-/OH- antiporter, exhibiting little Cl- uniport and either Cl-/Cl- or Cl-/HCO3- antiport activities.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2597129

Development of Hot Exhaust Emission Factors for Iranian-Made Euro-2 Certified Light-Duty Vehicles.

PubMed

Banitalebi, Ehsan; Hosseini, Vahid

2016-01-05

Emission factors (EFs) are fundamental, necessary data for air pollution research and scenario implementation. With the vision of generating national EFs of the Iranian transportation system, a portable emission measurement system (PEMS) was used to develop the basic EFs for a statistically significant sample of Iranian gasoline-fueled privately owned light duty vehicles (LDVs) operated in Tehran. A smaller sample size of the same fleet was examined by chassis dynamometer (CD) bag emission measurement tests to quantify the systematic differences between the PEMS and CD methods. The selected fleet was tested over four different routes of uphill highways, flat highways, uphill urban streets, and flat urban streets. Real driving emissions (RDEs) and fuel consumption (FC) rates were calculated by weighted averaging of the results from each route. The activity of the fleet over each route type was assumed as a weighting factor. The activity data were obtained from a Tehran traffic model. The RDEs of the selected fleet were considerably higher than the certified emission levels of all vehicles. Differences between Tehran real driving cycles and the New European Driving Cycle (NEDC) was attributed to the lower loading of NEDC. A table of EFs based on RDEs was developed for the sample fleet.

The changes of lumbar muscle flexion-relaxation phenomenon due to antero-posteriorly slanted ground surfaces.

PubMed

Hu, Boyi; Ning, Xiaopeng; Dai, Fei; Almuhaidib, Ibrahim

2016-09-01

Uneven ground surface is a common occupational injury risk factor in industries such as agriculture, fishing, transportation and construction. Studies have shown that antero-posteriorly slanted ground surfaces could reduce spinal stability and increase the risk of falling. In this study, the influence of antero-posteriorly slanted ground surfaces on lumbar flexion-relaxation responses was investigated. Fourteen healthy participants performed sagittally symmetric and asymmetric trunk bending motions on one flat and two antero-posteriorly slanted surfaces (-15° (uphill facing) and 15° (downhill facing)), while lumbar muscle electromyography and trunk kinematics were recorded. Results showed that standing on a downhill facing slanted surface delays the onset of lumbar muscle flexion-relaxation phenomenon (FRP), while standing on an uphill facing ground causes lumbar muscle FRP to occur earlier. In addition, compared to symmetric bending, when performing asymmetric bending, FRP occurred earlier on the contralateral side of lumbar muscles and significantly smaller maximum lumbar flexion and trunk inclination angles were observed. Practitioner Summary: Uneven ground surface is a common risk factor among a number of industries. In this study, we investigated the influence of antero-posteriorly slanted ground surface on trunk biomechanics during trunk bending. Results showed the slanted surface alters the lumbar tissue load-sharing mechanism in both sagittally symmetric and asymmetric bending.

The Effects of 3 Weeks of Uphill and Downhill Walking on Blood Lipids and Glucose Metabolism in Pre-Diabetic Men: A Pilot Study.

PubMed

Philippe, Marc; Gatterer, Hannes; Eder, Erika Maria; Dzien, Alexander; Somavilla, Matthias; Melmer, Andreas; Ebenbichler, Christoph; Müller, Tom; Burtscher, Martin

2017-03-01

The prevention of type 2 diabetes in persons at risk for diabetes is of utmost importance. Physical activity in general and even exercises at moderate intensities such as walking significantly reduce the risk of the development of type 2 diabetes. However, it is still a matter of debate whether lipids and glucose metabolism are differently affected by regular concentric (e.g., uphill walking) and eccentric (e.g., downhill walking) endurance exercise. The aim of this study was to investigate the effects of short-term (3 weeks) uphill and downhill walking on glucose metabolism and blood lipids in pre-diabetic middle-aged men in a real world setting. The study was designed as an investigator-initiated 2 group random selection pre-test post-test trial. Sixteen pre-diabetic men (age: 56.9 ± 5.1 years; BMI: 28.1 ± 2.3 kg·m -2 ) performed 9 uphill (n = 8) or 9 downhill (n = 8) walking sessions within 3 weeks. The primary outcomes were the markers of glucose metabolism and blood lipids measured before and after the training period. After uphill walking glucose tolerance (area under the curve of the oral glucose tolerance test: -43.25 ± 53.12 mg·dl -1 ; p = 0.05; effect size: 0.81), triglycerides (-48.75 ± 54.49 mg·dl -1 ; p = 0.036; effect size: 0.89), HDL-C (+7.86 ± 9.54 mg·dl -1 ; p = 0.05; effect size: 0.82) and total cholesterol/HDL-C ratio (-0.58 ± 0.41; p = 0.012; effect size: 1.39) had significantly improved. No significant metabolic adaptations were found after downhill walking. However, when adjusted for estimated energy expenditure, uphill and downhill walking had equal effects on almost all metabolic parameters. Moreover, the magnitude of the baseline impairments of glucose tolerance was significantly related to the extent of change in both groups. Depending on the fitness level and individual preferences both types of exercise may be useful for the prevention of type 2 diabetes and disorders in lipid metabolism.

Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.

PubMed

Stöggl, Thomas; Kampel, Wolfgang; Müller, Erich; Lindinger, Stefan

2010-01-01

The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques. Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed. The double-push skating technique was approximately 4.3% faster (P < 0.05) compared with the V2 skating technique and equally fast compared with the V1 skating technique. The double-push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P < 0.05), and equal poling frequencies and pole forces compared with the V1 technique. Cycle length, peak foot force, and knee extension ranges of motion and velocities were higher in the double-push technique compared with the V2 technique (all P values <0.05). Center of pressure was located more laterally in the double-push technique compared with the other two techniques (P < 0.05). All measured skiing speeds were drastically higher compared with former studies. The higher skiing speeds of the V1 and the double-push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.

Simulation of uphill/downhill running on a level treadmill using additional horizontal force.

PubMed

Gimenez, Philippe; Arnal, Pierrick J; Samozino, Pierre; Millet, Guillaume Y; Morin, Jean-Benoit

2014-07-18

Tilting treadmills allow a convenient study of biomechanics during uphill/downhill running, but they are not commonly available and there is even fewer tilting force-measuring treadmill. The aim of the present study was to compare uphill/downhill running on a treadmill (inclination of ± 8%) with running on a level treadmill using additional backward or forward pulling forces to simulate the effect of gravity. This comparison specifically focused on the energy cost of running, stride frequency (SF), electromyographic activity (EMG), leg and foot angles at foot strike, and ground impact shock. The main results are that SF, impact shock, and leg and foot angle parameters determined were very similar and significantly correlated between the two methods, the intercept and slope of the linear regression not differing significantly from zero and unity, respectively. The correlation of oxygen uptake (V̇O2) data between both methods was not significant during uphill running (r=0.42; P>0.05). V̇O2 data were correlated during downhill running (r=0.74; P<0.01) but there was a significant difference between the methods (bias=-2.51 ± 1.94 ml min(-1) kg(-1)). Linear regressions for EMG of vastus lateralis, biceps femoris, gastrocnemius lateralis, soleus and tibialis anterior were not different from the identity line but the systematic bias was elevated for this parameter. In conclusion, this method seems appropriate for the study of SF, leg and foot angle, impact shock parameters but is less applicable for physiological variables (EMG and energy cost) during uphill/downhill running when using a tilting force-measuring treadmill is not possible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Control of body's center of mass motion relative to center of pressure during uphill walking in the elderly.

PubMed

Hong, Shih-Wun; Leu, Tsai-Hsueh; Wang, Ting-Ming; Li, Jia-Da; Ho, Wei-Pin; Lu, Tung-Wu

2015-10-01

Uphill walking places more challenges on the locomotor system than level walking does when the two limbs work together to ensure the stability and continuous progression of the body over the base of support. With age-related degeneration older people may have more difficulty in maintaining balance during uphill walking, and may thus experience an increased risk of falling. The current study aimed to investigate using gait analysis techniques to determine the effects of age and slope angles on the control of the COM relative to the COP in terms of their inclination angles (IA) and the rate of change of IA (RCIA) during uphill walking. The elderly were found to show IAs similar to those of the young, but with reduced self-selected walking speed and RCIAs (P<0.05). After adjusting for walking speed differences, the elderly showed significantly greater excursions of IA in the sagittal plane (P<0.05) and increased RCIA at heel-strike and during single limb support (SLS) and double limb support (DLS) in the sagittal plane (P<0.05), and increased RCIA at heel-strike in the frontal plane (P<0.05). The RCIAs were significantly reduced with increasing slope angles (P<0.05). The current results show that the elderly adopted a control strategy different from the young during uphill walking, and that the IA and RCIA during walking provide a sensitive measure to differentiate individuals with different balance control abilities. The current results and findings may serve as baseline data for future clinical and ergonomic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of inclination angles on intra- and inter-limb load-sharing during uphill walking.

PubMed

Hong, Shih-Wun; Leu, Tsai-Hsueh; Li, Jia-Da; Wang, Ting-Ming; Ho, Wei-Ping; Lu, Tung-Wu

2014-01-01

Uphill walking is an inevitable part of daily living, placing more challenges on the locomotor system with greater risk of falls than level walking does. The current study aimed to investigate the effects of inclination angles on the inter-joint and inter-limb load-sharing during uphill walking in terms of total support moment and contributions of individual joint moments to the total support moment. Fifteen young adults walked up walkways with 0°, 5°, 10° and 15° of slope while kinematic and kinetic data were collected and analyzed. With increasing inclination angles, the first peak of the total support moment was increased with unaltered individual joint contributions, suggesting an unaltered inter-joint control pattern in the leading limb to meet the increased demands. The second peak of the total support moment remained unchanged with increasing inclination angles primarily through a compensatory redistribution of the hip and knee moments. During DLS, the leading limb shared the majority of the whole body support moments. The current results reveal basic intra- and inter-limb load-sharing patterns of uphill walking, which will be helpful for a better understanding of the control strategies adopted and for subsequent clinical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Sodium recognition by the Na+/Ca2+ exchanger in the outward-facing conformation

PubMed Central

Marinelli, Fabrizio; Almagor, Lior; Hiller, Reuben; Giladi, Moshe; Khananshvili, Daniel; Faraldo-Gómez, José D.

2014-01-01

Na+/Ca2+ exchangers (NCXs) are ubiquitous membrane transporters with a key role in Ca2+ homeostasis and signaling. NCXs mediate the bidirectional translocation of either Na+ or Ca2+, and thus can catalyze uphill Ca2+ transport driven by a Na+ gradient, or vice versa. In a major breakthrough, a prokaryotic NCX homolog (NCX_Mj) was recently isolated and its crystal structure determined at atomic resolution. The structure revealed an intriguing architecture consisting of two inverted-topology repeats, each comprising five transmembrane helices. These repeats adopt asymmetric conformations, yielding an outward-facing occluded state. The crystal structure also revealed four putative ion-binding sites, but the occupancy and specificity thereof could not be conclusively established. Here, we use molecular-dynamics simulations and free-energy calculations to identify the ion configuration that best corresponds to the crystallographic data and that is also thermodynamically optimal. In this most probable configuration, three Na+ ions occupy the so-called Sext, SCa, and Sint sites, whereas the Smid site is occupied by one water molecule and one H+, which protonates an adjacent aspartate side chain (D240). Experimental measurements of Na+/Ca2+ and Ca2+/Ca2+ exchange by wild-type and mutagenized NCX_Mj confirm that transport of both Na+ and Ca2+ requires protonation of D240, and that this side chain does not coordinate either ion at Smid. These results imply that the ion exchange stoichiometry of NCX_Mj is 3:1 and that translocation of Na+ across the membrane is electrogenic, whereas transport of Ca2+ is not. Altogether, these findings provide the basis for further experimental and computational studies of the conformational mechanism of this exchanger. PMID:25468964

Sodium recognition by the Na+/Ca2+ exchanger in the outward-facing conformation.

PubMed

Marinelli, Fabrizio; Almagor, Lior; Hiller, Reuben; Giladi, Moshe; Khananshvili, Daniel; Faraldo-Gómez, José D

2014-12-16

Na(+)/Ca(2+) exchangers (NCXs) are ubiquitous membrane transporters with a key role in Ca(2+) homeostasis and signaling. NCXs mediate the bidirectional translocation of either Na(+) or Ca(2+), and thus can catalyze uphill Ca(2+) transport driven by a Na(+) gradient, or vice versa. In a major breakthrough, a prokaryotic NCX homolog (NCX_Mj) was recently isolated and its crystal structure determined at atomic resolution. The structure revealed an intriguing architecture consisting of two inverted-topology repeats, each comprising five transmembrane helices. These repeats adopt asymmetric conformations, yielding an outward-facing occluded state. The crystal structure also revealed four putative ion-binding sites, but the occupancy and specificity thereof could not be conclusively established. Here, we use molecular-dynamics simulations and free-energy calculations to identify the ion configuration that best corresponds to the crystallographic data and that is also thermodynamically optimal. In this most probable configuration, three Na(+) ions occupy the so-called Sext, SCa, and Sint sites, whereas the Smid site is occupied by one water molecule and one H(+), which protonates an adjacent aspartate side chain (D240). Experimental measurements of Na(+)/Ca(2+) and Ca(2+)/Ca(2+) exchange by wild-type and mutagenized NCX_Mj confirm that transport of both Na(+) and Ca(2+) requires protonation of D240, and that this side chain does not coordinate either ion at Smid. These results imply that the ion exchange stoichiometry of NCX_Mj is 3:1 and that translocation of Na(+) across the membrane is electrogenic, whereas transport of Ca(2+) is not. Altogether, these findings provide the basis for further experimental and computational studies of the conformational mechanism of this exchanger.

Differential response of heat shock proteins to uphill and downhill exercise in heart, skeletal muscle, lung and kidney tissues.

PubMed

Lollo, Pablo C B; Moura, Carolina S; Morato, Priscila N; Amaya-Farfan, Jaime

2013-01-01

Running on a horizontal plane is known to increase the concentration of the stress biomarker heat-shock protein (HSP), but no comparison of the expression of HSP70 has yet been established between the uphill (predominantly concentric) and downhill (predominantly eccentric) muscle contractions exercise. The objective of the study was to investigate the relationships between eccentric and concentric contractions on the HSP70 response of the lung, kidney, gastrocnemius, soleus and heart. Twenty-four male Wistar weanling rats were divided into four groups: non-exercised and three different grades of treadmill exercise groups: horizontal, uphill (+7%) and downhill (-7% of inclination). At the optimal time-point of six hours after the exercise, serum uric acid, creatine kinase (CK) and lactate dehydrogenase (LDH) were determined by standard methods and HSP70 by the Western blot analysis. HSP70 responds differently to different types of running. For kidney, heart, soleus and gastrocnemius, the HSP70 expression increased, 230, 180, 150 and 120% respectively of the reference (horizontal). When the contraction was concentric (uphill) and compared to downhill the increase in response of HSP70 was greater in 80% for kidney, 75% for gastrocnemius, 60% for soleus and 280% for the heart. Uric acid was about 50% higher (0.64 ± 0.03 mg·dL(-1)) in the uphill group as compared to the horizontal or downhill groups. Similarly, the activities of serum CK and LDH were both 100% greater for both the uphill and downhill groups as compared to the horizontal group (2383 ± 253 and 647.00 ± 73 U/L, respectively). The responsiveness of HSP70 appeared to be quite different depending on the type of tissue, suggesting that the impact of exercise was not restricted to the muscles, but extended to the kidney tissue. The uphill exercise increases HSP70 beyond the eccentric type and the horizontal running was a lower HSP70 responsive stimulus. Key PointsExercise can induce increases in HSP70 in the lung, kidney and heart, and in the soleus and gastrocnemius muscles, probably due to systemic alterations such as hypoxia, increase in temperature and the production of free radicals.Predominantly concentric contractions (running uphill), seem to be the most efficient way of increasing the HSP70 concentrations in the different tissues, followed by eccentric contraction (downhill) and lastly the concentric-eccentric cycle (horizontal).The energy demand, already known to influence HSP70, appears not to be the only factor responsible for the response of these proteins, considering that for the kidney and the soleus muscle, downhill running was more efficient in raising the HSP70 response than horizontal running.Future research should explore the mechanisms by which the eccentric, concentric and eccentric-concentric contractions are capable of influencing the responses of the heat shock proteins, opening possibilities for increasing the levels of these proteins in desirable situations, such as to protect against excess free radicals or injuries.

[Secondary Full Title: Effects of high intensity interval training in plain and uphill regarding physical performance].

PubMed

Marterer, Natalie; Menz, Verena; Burtscher, Martin

2018-06-01

 As the number of HIITs is increasing in competitive and non-competitive sports, the risk of injuries and overload is increasing. There are no scientific data to support specific recommendations in regard to intensity, duration, number of intervals and gradient for HIIT that result in improved muscular parameters in athletes. Therefore the aim of this study was to compare HIIT in plain and uphill exercise, with respect to exercise tolerance and improvements in performance (VO 2max and 800 m running time in the plain and uphill).  17 well-trained sport students (10 females, 7 males; Ø VO 2max : 53.7 ml/min/kg) were randomly assigned to the plain group (plain; GE) (n = 8) or the uphill group (hill, GB) (n = 9). In the four weeks of training, all subjects completed 14 HIIT sessions. Each session consisted of 8 × 2 min running at 90 - 95 % of the maximal heart rate (HR max ), separated by 2 min recovery periods (work/rest ratio: 1:1). Before the intervention phase, subjects performed treadmill spirometry, a 800 m field test in the plain, as well as an 800 m uphill field test to determine baseline performance. One week after the intervention period, all subjects completed a retest of all measurements and tests. After the intervention, all subjects completed a questionnaire by giving their level of perceived exertion during training, using the BORG scale.  In GE, three subjects dropped out of the study because of overtraining. In GB, two subjects did not complete the study because of time constraints. The evaluation of the perceived exertion of the training in flat terrain showed a trend (p = 0.08; t = - 1.96) towards being perceived as more exhausting then in hilly terrain. A four week HIIT showed significant improvements in VO 2max by 5.2 % (p = 0.02; t = - 2.76), and a reduction in the running time in the plain by 4.6 % (p = 0.01; t = 3.48) and uphill by 6.3 % (p = 0.02; t = 2.77). No significant group effect was detected.  In this study, the application of HIIT leads to significant improvements in the performance of well-trained athletes. There is no evidence that the mode of training influenced the running improvements. However, uphill training tends to be better tolerated by the athletes. © Georg Thieme Verlag KG Stuttgart · New York.

Postphloem, Nonvascular Transfer in Citrus

PubMed Central

Koch, Karen E.; Avigne, Wayne T.

1990-01-01

Postphloem, nonvascular assimilate transport occurs over an unusually long area in citrus fruit and thus facilitates investigation of this process relative to sugar entry into many sink structures. Labeled photosynthates moving into juice tissues of grapefruit (Citrus paradisi Macf.) slowed dramatically after entering the postphloem transport path (parenchyma cells, narrow portions of segment epidermis, and hair-like, parenchymatous stalks of juice sacs). Kinetic, metabolic, and compositional data indicated that transfer through the nonvascular area was delayed many hours by temporary storage and/or equilibration with sugars in compartments along the postphloem path. Labeled assimilates were generally recovered as sucrose throughout the path, and extent of hexose formation enroute bore no apparent relationship to the assimilate transfer process. Even after 24 hours, radiolabel was restricted to discrete, highly localized areas directly between vascular bundles and juice sacs. Postphloem transfer occurred against an ascending sucrose concentration gradient in young fruit, whereas a descending gradient (favoring diffusion/cytoplasmic streaming) developed only later in maturation. Involvement of a postphloem bulk flow is complicated in the present instance by the extremely limited water loss from juice sacs either via transpiration or fluid backflow. Nonetheless, tissue expansion can account for a collective water inflow of at least 1.0 milliliter per day throughout the majority of juice sac development, thus providing a modest, but potentially important means of nonvascular solution flow. Overall, data indicate postphloem transfer (a) can follow highly localized paths through sizable nonvascular areas (up to 3.0 centimeters total), (b) appears to involve temporary storage and/or equilibration with compartmentalized sugars enroute, (c) can occur either against an overall up-hill sugar gradient (young tissues) or along a descending gradient (near full expansion), and (d) appears to involve at least some contribution by nonvascular mass flow accommodated by tissue expansion. Images Figure 1 Figure 4 PMID:16667632

9. View, oxidizer waste tanks and containment basin associated with ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. View, oxidizer waste tanks and containment basin associated with Components Test Laboratory (T-27) located directly uphill, looking north. Located uphill in the upper left portion of the photograph (from right to left) are the Oxidizer Conditioning Structure (T-28D), Long-Term Oxidizer Silo (T-28B), and Systems Integration Laboratory (T-28). - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Uphill and Downhill Walking in Multiple Sclerosis

PubMed Central

Samaei, Afshin; Hajihasani, Abdolhamid; Fatemi, Elham; Motaharinezhad, Fatemeh

2016-01-01

Background: Various exercise protocols have been recommended for patients with multiple sclerosis (MS). We investigated the effects of uphill and downhill walking exercise on mobility, functional activities, and muscle strength in MS patients. Methods: Thirty-four MS patients were randomly allocated to either the downhill or uphill treadmill walking group for 12 sessions (3 times/wk) of 30 minutes' walking on a 10% negative slope (n = 17) or a 10% positive slope (n = 17), respectively. Measurements were taken before and after the intervention and after 4-week follow-up and included fatigue by Modified Fatigue Impact Scale; mobility by Modified Rivermead Mobility Index; disability by Guy's Neurological Disability Scale; functional activities by 2-Minute Walk Test, Timed 25-Foot Walk test, and Timed Up and Go test; balance indices by Biodex Balance System; and quadriceps and hamstring isometric muscles by torque of left and right knee joints. Analysis of variance with repeated measures was used to investigate the intervention effects on the measurements. Results: After the intervention, significant improvement was found in the downhill group versus the uphill group in terms of fatigue, mobility, and disability indices; functional activities; balance indices; and quadriceps isometric torque (P < .05). The results were stable at 4-week follow-up. Conclusions: Downhill walking on a treadmill may improve muscle performance, functional activity, and balance control in MS patients. These findings support the idea of using eccentric exercise training in MS rehabilitation protocols. PMID:26917996

A comparison of slow, uphill and fast, level walking on lower extremity biomechanics and tibiofemoral joint loading in obese and nonobese adults.

PubMed

Haight, Derek J; Lerner, Zachary F; Board, Wayne J; Browning, Raymond C

2014-02-01

We determined if slow, uphill walking (0.75 m/s, 6°) reduced tibiofemoral (TF) loading compared to faster, level walking (1.50 m/s) in obese and nonobese adults. We collected kinematic, kinetic, and electromyographic data as 9 moderately obese and 10 nonobese participants walked on a dual-belt instrumented treadmill. We used OpenSim to scale a musculoskeletal model and calculate joint kinematics, kinetics, muscle forces, and TF forces. Compressive TF forces were greater in the obese adults during both speed/grade combinations. During level walking, obese participants walked with a straighter leg than nonobese participants, resulting in early stance vasti muscle forces that were similar in the obese and nonobese participants. Early stance peak compressive TF forces were reduced by 23% in obese (2,352 to 1,811 N) and 35% in nonobese (1,994 to 1,303 N) individuals during slow, uphill walking compared to brisk level walking. Late stance peak TF forces were similar across speeds/grades, but were greater in obese (∼2,900 N) compared to nonobese (∼1,700 N) individuals. Smaller early stance TF loads and loading rates suggest that slow, uphill walking may be appropriate exercise for obese individuals at risk for musculoskeletal pathology or pain. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker.

PubMed

Lindemann, Ulrich; Schwenk, Michael; Schmitt, Syn; Weyrich, Michael; Schlicht, Wolfgang; Becker, Clemens

2017-08-01

Wheeled walkers are recommended to improve walking performance in older persons and to encourage and assist participation in daily life. Nevertheless, using a wheeled walker can cause serious problems in the natural environment. This study aimed to compare uphill and downhill walking with walking level in geriatric patients using a wheeled walker. Furthermore, we investigated the effect of using a wheeled walker with respect to dual tasking when walking level. A total of 20 geriatric patients (median age 84.5 years) walked 10 m at their habitual pace along a level surface, uphill and downhill, with and without a standard wheeled walker. Gait speed, stride length and cadence were assessed by wearable sensors and the walk ratio was calculated. When using a wheeled walker while walking level the walk ratio improved (0.58 m/[steps/min] versus 0.57 m/[steps/min], p = 0.023) but gait speed decreased (1.07 m/s versus 1.12 m/s, p = 0.020) when compared to not using a wheeled walker. With respect to the walk ratio, uphill and downhill walking with a wheeled walker decreased walking performance when compared to level walking (0.54 m/[steps/min] versus 0.58 m/[steps/min], p = 0.023 and 0.55 m/[steps/min] versus 0.58 m/[steps/min], p = 0.001, respectively). At the same time, gait speed decreased (0.079 m/s versus 1.07 m/s, p < 0.0001) or was unaffected. The use of a wheeled walker improved the quality of level walking but the performance of uphill and downhill walking was worse compared to walking level when using a wheeled walker.

Pendular energy transduction within the step during human walking on slopes at different speeds

PubMed Central

Dewolf, Arthur H.; Ivanenko, Yuri P.; Lacquaniti, Francesco

2017-01-01

When ascending (descending) a slope, positive (negative) work must be performed to overcome changes in gravitational potential energy at the center of body mass (COM). This modifies the pendulum-like behavior of walking. The aim of this study is to analyze how energy exchange and mechanical work done vary within a step across slopes and speeds. Ten subjects walked on an instrumented treadmill at different slopes (from -9° to 9°), and speeds (between 0.56 and 2.22 m s-1). From the ground reaction forces, we evaluated energy of the COM, recovery (i.e. the potential-kinetic energy transduction) and pendular energy savings (i.e. the theoretical reduction in work due to this recovered energy) throughout the step. When walking uphill as compared to level, pendular energy savings increase during the first part of stance (when the COM is lifted) and decreases during the second part. Conversely in downhill walking, pendular energy savings decrease during the first part of stance and increase during the second part (when the COM is lowered). In uphill and downhill walking, the main phase of external work occurs around double support. Uphill, the positive work phase is extended during the beginning of single support to raise the body. Downhill, the negative work phase starts before double support, slowing the downward velocity of the body. Changes of the pendulum-like behavior as a function of slope can be illustrated by tilting the 'classical compass model' backwards (uphill) or forwards (downhill). PMID:29073208

Gradual downhill running improves age-related skeletal muscle and bone weakness: implication of autophagy and bone morphogenetic proteins.

PubMed

Kim, Jeong-Seok; Lee, Young-Hee; Yi, Ho-Keun

2016-12-01

What is the central question of this study? Exercise training by running has an effect on age-related muscle and bone wasting that improves physical activity and quality of life in the elderly. However, the effect of downhill running on age-related muscle and bone wasting, and its mechanisms, are unclear. What is the main finding and its importance? Gradual downhill running can improve skeletal muscle growth and bone formation by enhancing autophagy and bone morphogenetic protein signalling in aged rats. Therefore, downhill running exercise might be a practical intervention to improve skeletal muscle and bone protection in the elderly. Recent evidence suggests that autophagy and the bone morphogenetic protein (BMP) signalling pathway regulate skeletal muscle growth and bone formation in aged rats. However, the effect of downhill running on muscle growth and bone formation is not well understood. Thus, we investigated the effect of downhill and uphill running on age-related muscle and bone weakness. Young and late middle-aged rats were randomly assigned to control groups (young, YC; and late middle-aged, LMC) and two types of running training groups (late middle-aged downhill, LMD; and late middle-aged uphill, LMU). Training was progressively carried out on a treadmill at a speed of 21 m min -1 with a slope of +10 deg for uphill training versus 16 m min -1 with a slope of -16 deg for downhill training, both for 60 min day -1 , 5 days week -1 for 8 weeks. Downhill and uphill training increased autophagy-related protein 5, microtubule-associated protein light chain, Beclin-1 and p62 proteins in aged rats. In addition, superoxide dismutase, haem oxygenase-1 and the BMP signalling pathway were elevated. Phosphorylation of mammalian target of rapamycin and myogenic differentiation were increased significantly in the LMD and LMU groups. Consequently, in the femur, BMP-2, BMP-7 and autophagy molecules were highly expressed in the LMD and LMU groups. These results suggest that both downhill and uphill training appear to have a positive effect on expression of autophagy molecules and BMPs. In particular, these physiological adaptations from gradual downhill exercise have an effect on bone morphological changes and muscle quality similar to gradual uphill training interventions in ageing. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

The Effects of Permafrost Thaw on Organic Matter Quality and Availability Along a Hill Slope in Northeastern Siberia

NASA Astrophysics Data System (ADS)

Connolly, C. T.; Spawn, S.; Ludwig, S.; Schade, J. D.; Natali, S.

2014-12-01

Climate warming and permafrost thaw in northeastern Siberia are expected to change the quantity and quality of organic matter (OM) transported through watersheds, releasing previously frozen carbon (C) to biologically available pool. Hill slopes have shown to influence the distribution of OM, resulting in a downhill accumulation of available C and nutrients relative to uphill. Here we examine how future permafrost thaw will change OM quality and availability along a hill slope in a larch-dominated watershed. We collected soils from the thawed organic and mineral layers, and 1m deep permafrost cores for dissolved organic C (DOC) and total dissolved N (TDN), C composition from measures of colored dissolved organic matter (CDOM), DOC lability from biodegradable DOC (BDOC) incubations, C and nutrient availability from extracellular-enzyme assays (EEA's), and microbial respiration from aerobic soil incubations. Here we show that organic soils (O), in comparison to mineral soils (M) and permafrost (P) are the most abundant source of C (avg O DOC: 51.6mg/L), exhibiting low molecular complexity (avg O SUVA254: 4.05) and high quality. Evidence suggests permafrost OM may be an equally abundant, and more labile source of C than mineral soils (highest P DOC: 16.1 mg/L, lowest P SUVA254: 6.32; median M DOC: 18.5 mg/L, median M SUVA254: 24.0). Furthermore, we demonstrate that there may be a positive relationship in the rate of C mineralization and distance downhill, showing 15-30% greater CO2 production/gC downhill relative to uphill. Evidence also supports a similar relationship in permafrost DOC content and molecular complexity, showing more DOC of a lower complexity further downhill. This indicates DOC transport may have been occurring through the active layer and downhill during ice-rich permafrost formation, and may supply a labile source of carbon to lowland areas and adjacent stream networks upon thaw.

Electron Flow in Multiheme Bacterial Cytochromes is a Balancing Act Between Heme Electronic Interaction and Redox Potentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breuer, Marian; Rosso, Kevin M.; Blumberger, Jochen

The naturally widespread process of electron transfer from metal reducing bacteria to extracellular solid metal oxides entails unique biomolecular machinery optimized for long-range electron transport. To perform this function efficiently microorganisms have adapted multi-heme c-type cytochromes to arrange heme cofactors into wires that cooperatively span the cellular envelope, transmitting electrons along distances greater than 100 Angstroms. Implications and opportunities for bionanotechnological device design are self-evident. However, at the molecular level how these proteins shuttle electrons along their heme wires, navigating intraprotein intersections and interprotein interfaces effciently, remains a mystery so far inaccessible to experiment. To shed light on this criticalmore » topic, we carried out extensive computer simulations to calculate Marcus theory quantities for electron transfer along the ten heme cofactors in the recently crystallized outer membrane cytochrome MtrF. The combination of electronic coupling matrix elements with free energy calculations of heme redox potentials and reorganization energies for heme-to-heme electron transfer allows the step-wise and overall electron transfer rate to be estimated and understood in terms of structural and dynamical characteristics of the protein. By solving a master equation for electron hopping, we estimate an intrinsic, maximum possible electron flux through solvated MtrF of 104-105 s-1, consistent with recently measured rates for the related MtrCAB protein complex. Intriguingly, this flux must navigate thermodynamically uphill steps past low potential hemes. Our calculations show that the rapid electron transport through MtrF is the result of a clear correlation between heme redox potential and the strength of electronic coupling along the wire: Thermodynamically uphill steps occur only between electronically well connected stacked heme pairs. This suggests that the protein evolved to harbor low potential hemes, presumably necessary for reduction of certain soluble substrates, without slowing down electron ow. These findings are particularly profound in light of the apparently well conserved staggered cross heme wire structural motif in functionally related outer-membrane proteins.« less

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking

PubMed Central

Seay, Joseph F.; Gregorczyk, Karen N.; Hasselquist, Leif

2016-01-01

Abstract Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions. Double support percentage increased with load and inclination change from uphill to level walking, with a 0.4% stance greater increase at the 20 kg condition compared to 00 kg. As inclination changed from uphill to downhill, the step rate increased more overground (4.3 ± 3.5 steps/min) than during treadmill walking (1.7 ± 2.3 steps/min). For the 40 kg condition, the standard deviations were larger than the 00 kg condition for both the step rate and double support percentage. There was no change between modes for step rate standard deviation. For overground compared to treadmill walking, standard deviation for stride length and double support percentage increased and decreased, respectively. Changes in the load of up to 40 kg, inclination of 6% grade away from the level (i.e., uphill or downhill) and mode (treadmill and overground) produced small, yet statistically significant changes in spatiotemporal parameters. Variability, as assessed by standard deviation, was not systematically lower during treadmill walking compared to overground walking. Due to the small magnitude of changes, treadmill walking appears to replicate the spatiotemporal parameters of overground walking. PMID:28149338

A pilot study of the effect of Kinesiology tape on knee proprioception after physical activity in healthy women.

PubMed

Hosp, Simona; Bottoni, Giuliamarta; Heinrich, Dieter; Kofler, Philipp; Hasler, Michael; Nachbauer, Werner

2015-11-01

Kinesiology tape has gained significant popularity in recent years and is widely used as an adjunct for treatment and prevention of musculoskeletal injuries. However, evidence regarding its influence on knee proprioception is scarce. The purpose of this study was to evaluate the effect of Kinesiology tape on knee proprioception after physical activity in healthy women. It was hypothesized that Kinesiology tape enhances knee proprioception. Longitudinal analysis, pretest-posttest design. Twelve young women with healthy knees were tested for knee proprioception without the use of Kinesiology tape and wearing Kinesiology tape at the knee. The joint position sense was measured at the start and after a 30-min uphill walking protocol on a treadmill. Outcome was the knee angle deviation. No significant difference of proprioceptive performance between the application with Kinesiology tape and without Kinesiology tape was found after uphill walking (p > 0.05). However, when the participants' results for knee angle deviation were graded into good (< 6.1°) and poor ( > 6.1°), Kinesiology tape significantly enhanced those with poor proprioceptive ability after uphill walking, compared to the untaped knee (p = 0.002). This study has shown that the application of Kinesiology tape did not improve knee proprioception in a group of healthy young women. However, it also has demonstrated that Kinesiology tape provided significant proprioceptive enhancement at the knee joint after uphill walking in healthy women with poor proprioceptive ability. This may support its use in sports medicine for preventing knee injuries. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of Afforestation and Natural Revegetation on Soil Moisture Dynamics in Paired Watersheds in the Loess Plateau of China

NASA Astrophysics Data System (ADS)

Jin, Z.; Guo, L.; Lin, H.; Wang, Y.; Chu, G.

2017-12-01

In this study, a paired of small watersheds, which are artificial forestland and natural grassland, respectively, were selected. The two watersheds have been set up since 1954 and the time of revegetation is more than 60 years. Their differences in event and seasonal dynamics of soil moisture were investigated and the effects of vegetation and landform were analyzed. Results showed that consecutive small events higher than 22 mm and single events higher than 16.6 mm could recharge the soil moisture of the two watersheds, but no rainfall event was observed to recharge the soil moisture of 100 cm within 2 weeks after rainfall initiation. Moreover, the two contrasting watersheds showed no difference in rainfall threshold for effective soil moisture replenishment and also had similar patterns of soil water increment with the increase of initial soil water content and rainfall intensity. The changing vegetation cover and coverage at different landforms (uphill slope land and downhill gully) showed the most significant impact on event and seasonal dynamics of soil moisture. The strong interception, evaporation and transpiration of tree canopy and understory vegetation in the gully of the forestland showed the most negative impacts on soil moisture replenishment. Moreover, dense surface grass biomass (living and dead) in the grassland also showed negative impacts on effective soil moisture recharge. Landform itself showed no significant impact on event soil moisture dynamics through changing the initial soil water content and soil texture, while site differences in slope gradient and soil temperature could affect the seasonal soil water content. During the growing season of May-October, the forestland showed 1.3% higher soil water content than that of the grassland in the landform of uphill slope land; while in the landform of downhill gully, the grassland showed 4.3% higher soil water content than that of the forestland. Many studies have predicted that there will be more extreme precipitation in the global and local dry regions in the 21st century, and thus the threshold and mechanisms of effective rainfall replenishment should be strengthened. Keywords: Soil water monitoring; paired watersheds; afforestation; natural recovery; landform Corresponding author: Prof. Dr. Zhao Jin, jinzhao@ieecas.cn

Mudstone Mineralogy from Curiosity CheMin, 2013 to 2016

NASA Image and Video Library

2016-12-13

This series of pie charts shows similarities and differences in the mineral compositions of mudstones at 10 sites where NASA's Curiosity Mars rover collected rock-powder samples and analyzed them with the rover's Chemistry and Mineralogy (CheMin) instrument. The charts are arrayed in chronological order, with an indication of relative elevation as the rover first sampled two sites on the floor of Gale Crater in 2013 and later began climbing the crater's central mound, Mount Sharp. The pie chart farthest to the right and uphill shows composition at the "Sebina" target, sampled in October 2016. Five non-mudstone rock targets that the rover drilled and analyzed within this time frame are not included. The mineralogical variations in these mudstones may be due to differences in any or all of these factors: the source materials deposited by water that entered lakes, the processes of sedimentation and rock forming, and how the rocks were later altered. One trend that stands out is that the mineral jarosite -- shown in purple -- was more prominent in the "Pahrump Hills" area of lower Mount Sharp than at sites examined either earlier or later. Jarosite is an indicator of acidic water. Mudstone layers uphill from Pahrump Hills have barely detectable amounts of jarosite, indicating a shift away from acidic conditions in these overlying -- thus younger -- layers. Clay minerals, shown as green, declined in abundance at sites midway through this series, then came back as the rover climbed higher. Each drilled-and-analyzed target is identified with a two-letter abbreviation: JK for "John Klein," CB for "Cumberland." CH for "Confidence Hills," MJ for "Mojave," TP for "Telegraph Peak," BK for "Buckskin," OD for "Oudam," MB for "Marimba," QL for "Quela," and SB for Sebina. http://photojournal.jpl.nasa.gov/catalog/PIA21146

Footwear traction and three-dimensional kinematics of level, downhill, uphill and cross-slope walking.

PubMed

Wannop, John W; Worobets, Jay T; Ruiz, Rodrigo; Stefanyshyn, Darren J

2014-01-01

Outdoor activities are a popular form of recreation, with hiking being the most popular outdoor activity as well as being the most prevalent in terms of injury. Over the duration of a hike, trekkers will encounter many different sloped terrains. Not much is known about the required traction or foot-floor kinematics during locomotion on these sloped surfaces, therefore, the purpose was to determine the three-dimensional foot-floor kinematics and required traction during level, downhill, uphill and cross-slope walking. Ten participants performed level, uphill, downhill and cross-slope walking along a 19° inclined walkway. Ground reaction force data as well as 3D positions of retro reflective markers attached to the shoe were recorded using a Motion Analysis System. Peak traction coefficients and foot-floor kinematics during sloped walking were compared to level walking. When walking along different sloped surfaces, the required traction coefficients at touchdown were not different from level walking, therefore, the increased likelihood of heel slipping during hiking is potentially due to the presence of loose material (rocks, dirt) on hiking slopes, rather than the overall lack of traction. Differences in required traction were seen at takeoff, with uphill and cross-sloped walking requiring a greater amount of traction compared to level walking. Changes in sagittal plane, frontal plane and transverse plane foot-floor angles were seen while walking on the sloped surfaces. Rapid foot-floor eversion was observed during cross-slope walking which could place the hiker at risk of injury with a misstep or if there was a slight slip. Copyright © 2014 Elsevier B.V. All rights reserved.

Protonation-dependent conformational dynamics of the multidrug transporter EmrE

PubMed Central

Dastvan, Reza; Mishra, Smriti; Meiler, Jens; Mchaourab, Hassane S.

2016-01-01

The small multidrug transporter from Escherichia coli, EmrE, couples the energetically uphill extrusion of hydrophobic cations out of the cell to the transport of two protons down their electrochemical gradient. Although principal mechanistic elements of proton/substrate antiport have been described, the structural record is limited to the conformation of the substrate-bound state, which has been shown to undergo isoenergetic alternating access. A central but missing link in the structure/mechanism relationship is a description of the proton-bound state, which is an obligatory intermediate in the transport cycle. Here we report a systematic spin labeling and double electron electron resonance (DEER) study that uncovers the conformational changes of EmrE subsequent to protonation of critical acidic residues in the context of a global description of ligand-induced structural rearrangements. We find that protonation of E14 leads to extensive rotation and tilt of transmembrane helices 1–3 in conjunction with repacking of loops, conformational changes that alter the coordination of the bound substrate and modulate its access to the binding site from the lipid bilayer. The transport model that emerges from our data posits a proton-bound, but occluded, resting state. Substrate binding from the inner leaflet of the bilayer releases the protons and triggers alternating access between inward- and outward-facing conformations of the substrate-loaded transporter, thus enabling antiport without dissipation of the proton gradient. PMID:26787875

Active urea transport in lower vertebrates and mammals.

PubMed

Bankir, Lise

2014-01-01

Some unicellular organisms can take up urea from the surrounding fluids by an uphill pumping mechanism. Several active (energy-dependent) urea transporters (AUTs) have been cloned in these organisms. Functional studies show that active urea transport also occurs in elasmobranchs, amphibians, and mammals. In the two former groups, active urea transport may serve to conserve urea in body fluids in order to balance external high ambient osmolarity or prevent desiccation. In mammals, active urea transport may be associated with the need to either store and/or reuse nitrogen in the case of low nitrogen supply, or to excrete nitrogen efficiently in the case of excess nitrogen intake. There are probably two different families of AUTs, one with a high capacity able to establish only a relatively modest transepithelial concentration difference (renal tubule of some frogs, pars recta of the mammalian kidney, early inner medullary collecting duct in some mammals eating protein-poor diets) and others with a low capacity but able to maintain a high transepithelial concentration difference that has been created by another mechanism or in another organ (elasmobranch gills, ventral skin of some toads, and maybe mammalian urinary bladder). Functional characterization of these transporters shows that some are coupled to sodium (symports or antiports) while others are sodium-independent. In humans, only one genetic anomaly, with a mild phenotype (familial azotemia), is suspected to concern one of these transporters. In spite of abundant functional evidence for such transporters in higher organisms, none have been molecularly identified yet.

Water ascent in trees and lianas: the cohesion-tension theory revisited in the wake of Otto Renner.

PubMed

Bentrup, Friedrich-Wilhelm

2017-03-01

The cohesion-tension theory of water ascent (C-T) has been challenged over the past decades by a large body of experimental evidence obtained by means of several minimum or non-invasive techniques. The evidence strongly suggests that land plants acquire water through interplay of several mechanisms covered by the multi-force theory of (U. Zimmermann et al. New Phytologist 162: 575-615, 2004). The diversity of mechanisms includes, for instance, water acquisition by inverse transpiration and thermodynamically uphill transmembrane water secretion by cation-chloride cotransporters (L.H. Wegner, Progress in Botany 76:109-141, 2014). This whole plant perspective was opened by Otto Renner at the beginning of the last century who supported experimentally the strictly xylem-bound C-T mechanism, yet anticipated that the water ascent involves both the xylem conduit and parenchyma tissues. The survey also illustrates the known paradigm that new techniques generate new insights, as well as a paradigm experienced by Max Planck that a new scientific idea is not welcomed by the community instantly.

Local dynamic stability of lower extremity joints in lower limb amputees during slope walking.

PubMed

Chen, Jin-Ling; Gu, Dong-Yun

2013-01-01

Lower limb amputees have a higher fall risk during slope walking compared with non-amputees. However, studies on amputees' slope walking were not well addressed. The aim of this study was to identify the difference of slope walking between amputees and non-amputees. Lyapunov exponents λS was used to estimate the local dynamic stability of 7 transtibial amputees' and 7 controls' lower extremity joint kinematics during uphill and downhill walking. Compared with the controls, amputees exhibited significantly lower λS in hip (P=0.04) and ankle (P=0.01) joints of the sound limb, and hip joints (P=0.01) of the prosthetic limb during uphill walking, while they exhibited significantly lower λS in knee (P=0.02) and ankle (P=0.03) joints of the sound limb, and hip joints (P=0.03) of the prosthetic limb during downhill walking. Compared with amputees level walking, they exhibited significantly lower λS in ankle joints of the sound limb during both uphill (P=0.01) and downhill walking (P=0.01). We hypothesized that the better local dynamic stability of amputees was caused by compensation strategy during slope walking.

A late Holocene pollen record from proglacial Oblong Tarn, Mount Kenya.

PubMed

Courtney Mustaphi, Colin J; Gajewski, Konrad; Marchant, Rob; Rosqvist, Gunhild

2017-01-01

High-elevation ecosystems, such as those on Mount Kenya are undergoing significant changes, with accelerated glacial ice losses over the twentieth century creating new space for alpine plants to establish. These ecosystems respond rapidly to climatic variability and within decades of glacial retreat, Afroalpine pioneering taxa stabilize barren land and facilitate soil development, promoting complex patches of alpine vegetation. Periglacial lake sediment records can be used to examine centennial and millennial scale variations in alpine and montane vegetation compositions. Here we present a 5300-year composite pollen record from an alpine tarn (4370 m asl) in the Hausberg Valley of Mount Kenya. Overall, the record shows little apparent variation in the pollen assemblage through time with abundant montane forest taxa derived and transported from mid elevations, notably high abundances of aerophilous Podocarpus pollen. Afroalpine taxa included Alchemilla, Helichrysum and Dendrosenecio-type, reflecting local vegetation cover. Pollen from the ericaceous zone was present throughout the record and Poaceae percentages were high, similar to other high elevation pollen records from eastern Africa. The Oblong Tarn record pollen assemblage composition and abundances of Podocarpus and Poaceae since the late Holocene (~4000 cal yr BP-present) are similar to pollen records from mid-to-high elevation sites of nearby high mountains such as Mount Elgon and Kilimanjaro. These results suggest a significant amount of uphill pollen transport with only minor apparent variation in local taxa. Slight decreasing trends in alpine and ericaceous taxonomic groups show a long-term response to global late Holocene cooling and a step decrease in rate of change estimated from the pollen assemblages at 3100 cal yr BP in response to regional hydroclimatic variability. Changes in the principal component axis scores of the pollen assemblage were coherent with an independent mid-elevation temperature reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300-3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs.

The Effect of Uphill and Downhill Slopes on Weight Transfer, Alignment and Shot Outcome in Golf.

PubMed

Blenkinsop, Glen M; Liang, Ying; Gallimore, Nicholas J; Hiley, Michael J

2018-04-13

The aim of the study was to examine changes in weight transfer, alignment and shot outcome during golf shots from flat, uphill, and downhill slopes. Twelve elite male golfers hit 30 shots with a six-iron from a computer assisted rehabilitation environment (CAREN) used to create 5° slopes while collecting 3D kinematics and kinetics of the swing. A launch monitor measured performance outcomes. A shift in the centre of pressure was found throughout the swing when performed on a slope, with the mean position moving approximately 9% closer to the lower foot. The golfers attempted to remain perpendicular to the slope, resulting in the weight transfer towards the lower foot. The golfers adopted a wider stance in the sloped conditions and moved the ball towards the higher foot at address. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. As predicted by the coaching literature, golfers were more likely to hit shots to the left from an uphill slope and to the right for a downhill slope. No consistent compensatory adjustments in alignment at address or azimuth were found, with the change in final shot dispersion due to the lateral spin of the ball.

Curiosity is Ready for Clay (Highlighted)

NASA Image and Video Library

2018-03-22

This mosaic taken by NASA's Mars Curiosity rover looks uphill at Mount Sharp, which Curiosity has been climbing. Highlighted in white is an area with clay-bearing rocks that scientists are eager to explore; it could shed additional light on the role of water in creating Mount Sharp. The mosaic was assembled from dozens of images taken by Curiosity's Mast Camera (Mastcam). It was taken on Sol 1931 back in January. Mount Sharp stands in the middle of Gale Crater, which is 96 miles (154 kilometers) in diameter. This mound, which Curiosity has been climbing since 2014, likely formed in the presence of water at various points of time in Mars ancient history. That makes it an ideal place to study how water influenced the habitability of Mars billions of years ago. The scene has been white-balanced so the colors of the rock materials resemble how they would appear under daytime lighting conditions on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22312

Curiosity is Ready for Clay

NASA Image and Video Library

2018-03-22

This mosaic taken by NASA's Mars Curiosity rover looks uphill at Mount Sharp, which Curiosity has been climbing. Spanning the center of the image is an area with clay-bearing rocks that scientists are eager to explore; it could shed additional light on the role of water in creating Mount Sharp. The mosaic was assembled from dozens of images taken by Curiosity's Mast Camera (Mastcam). It was taken on Sol 1931 back in January. Mount Sharp stands in the middle of Gale Crater, which is 96 miles (154 kilometers) in diameter. This mound, which Curiosity has been climbing since 2014, likely formed in the presence of water at various points of time in Mars ancient history. That makes it an ideal place to study how water influenced the habitability of Mars billions of years ago. The scene has been white-balanced so the colors of the rock materials resemble how they would appear under daytime lighting conditions on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22313

Protection against fire in the mountainous forests of Greece case study: forest complex of W. Nestos

NASA Astrophysics Data System (ADS)

Drosos, Vasileios C.; Giannoulas, Vasileios J.; Stergiadou, Anastasia; Karagiannis, Evaggelos; Doukas, Aristotelis-Kosmas G.

2014-08-01

Forest fires are an ancient phenomenon. Appear, however, with devastating frequency and intensity over the last 30 years. In our country, the climatic conditions in combination with the intense relief, favor their rapid spread. Considering the fact that environmental conditions provided for decades even worse (increased temperature, drought and vegetation), then the problem of forest fires in our country, is expected to become more intense. The work focuses on the optimization model of the opening up of the forest mountain areas taking into account the prevention and suppression of forest fires. Research area is the mountain forest complex of W. Nestos of Drama Prefecture. The percentage of forest protection area is examined under the light whether the total hose length corresponds to the actual operational capacity to reach a fire source. For this reason are decided to present a three case study concerning area of the forest being protected by fire extinguishing vehicles. The first one corresponds to a fire suppression bandwidth (buffer zone) with a capacity radius of 150m uphill and 250m downhill from the origin point where the fire extinguishing vehicle stands. The second one corresponds to a fire suppression capacity of 200m uphill and 400m downhill and the third one corresponds to a fire suppression capacity of 300m uphill and 500m downhill. The most important forest technical infrastructures to prevent fire are roads network (opening up) for fire protection and buffer zones. Patrols of small and agile 4 × 4 appropriately equipped (pipe length of 500 meters and putting pressure on uphill to 300 meters) for the first attack of the fire in the summer months coupled with early warning of fire observatories adequately cover the forest protection of W. Nestos complex. But spatial distribution needed improvements to a road density of the optimum economic Dec, both forest protection and for better management (skidding) of woody capital.

Mars manned transportation vehicle

NASA Technical Reports Server (NTRS)

Perez-Davis, Marla E.; Faymon, Karl A.

1987-01-01

A viable power system technology for a surface transportation vehicle to explore the planet Mars is presented. A number of power traction systems were investigated, and it was found that a regenerative hydrogen-oxygen fuel cell appears to be attractive for a manned Mars rover application. Mission requirements were obtained from the Manned Mars Mission Working Group. Power systems weights, power, and reactants requirements were determined as a function of vehicle weights for vehicles weighing from 6,000 to 16,000 lb (2,722 to 7,257 kg), (Earth weight). The vehicle performance requirements were: velocity, 10 km/hr; range, 100 km; slope climbing capability, 30 deg uphill for 50 km; mission duration, 5 days; and crew, 5. Power requirements for the operation of scientific equipment and support system capabilities were also specified and included in this study. The concept developed here would also be applicable to a Lunar based vehicle for Lunar exploration. The reduced gravity on the Lunar surface, (over that on the Martian surface), would result in an increased range or capability over that of the Mars vehicle since many of the power and energy requirements for the vehicle are gravity dependent.

Multi-field plasma sandpile model in tokamaks and applications

NASA Astrophysics Data System (ADS)

Peng, X. D.; Xu, J. Q.

2016-08-01

A multi-field sandpile model of tokamak plasmas is formulated for the first time to simulate the dynamic process with interaction between avalanche events on the fast/micro time-scale and diffusive transports on the slow/macro time-scale. The main characteristics of the model are that both particle and energy avalanches of sand grains are taken into account simultaneously. New redistribution rules of a sand-relaxing process are defined according to the transport properties of special turbulence which allows the uphill particle transport. Applying the model, we first simulate the steady-state plasma profile self-sustained by drift wave turbulences in the Ohmic discharge of a tokamak. A scaling law as f = a q0 b + c for the relation of both center-density n ( 0 ) and electron (ion) temperatures T e ( 0 ) ( T i ( 0 ) ) with the center-safety-factor q 0 is found. Then interesting work about the nonlocal transport phenomenon observed in tokamak experiments proceeds. It is found that the core electron temperature increases rapidly in response to the edge cold pulse and inversely it decreases in response to the edge heat pulse. The results show that the nonlocal response of core electron temperature depending on the amplitudes of background plasma density and temperature is more remarkable in a range of gas injection rate. Analyses indicate that the avalanche transport caused by plasma drift instabilities with thresholds is a possible physical mechanism for the nonlocal transport in tokamaks. It is believed that the model is capable of being applied to more extensive questions occurring in the transport field.

Modeling water quality effects of structural and operational changes to Scoggins Dam and Henry Hagg Lake, Oregon

USGS Publications Warehouse

Sullivan, Annett B.; Rounds, Stewart A.

2006-01-01

To meet water quality targets and the municipal and industrial water needs of a growing population in the Tualatin River Basin in northwestern Oregon, an expansion of Henry Hagg Lake is under consideration. Hagg Lake is the basin's primary storage reservoir and provides water during western Oregon's typically dry summers. Potential modifications include raising the dam height by 6.1 meters (20 feet), 7.6 meters (25 feet), or 12.2 meters (40 feet); installing additional outlets (possibly including a selective withdrawal tower); and adding additional inflows to provide greater reliability of filling the enlarged reservoir. One method of providing additional inflows is to route water from the upper Tualatin River through a tunnel and into Sain Creek, a tributary to the lake. Another option is to pump water from the Tualatin River (downstream of the lake) uphill and into the reservoir during the winter--the 'pump-back' option. A calibrated CE-QUAL-W2 model of Henry Hagg Lake's hydrodynamics, temperature, and water quality was used to examine the effect of these proposed changes on water quality in the lake and downstream. Most model scenarios were run with the calibrated model for 2002, a typical water year; a few scenarios were run for 2001, a drought year. More...

Surprising features of particle dynamics in channel-facilitated transport

NASA Astrophysics Data System (ADS)

Berezhkovskii, Alexander M.; Bezrukov, Sergey M.

2007-06-01

We analyze the consequences of interactions between the pore and the translocating molecule within the framework of a continuous diffusion model using the Smoluchowski equation with the radiation boundary conditions. We describe the solute-pore interaction in terms of the potential of mean force. Several of our analytical findings are quite counterintuitive. Three of the examples to be discussed here are: (i) "Sticking" to the channel slows down translocation (a particle spends more time in the channel) but increases the flux; (ii) If the potential well modeling the particle-channel interaction occupies only a part of the channel length, the average translocation time is non-monotonic in the width of the potential well, first increasing and then decreasing; (iii) At a finite potential bias applied to the channel, the mean "up-hill" and "downhill" particle translocation times (and their distributions) are identical.

Lactose carrier mutants of Escherichia coli with changes in sugar recognition (lactose versus melibiose).

PubMed

Varela, M F; Brooker, R J; Wilson, T H

1997-09-01

The purpose of this research was to identify amino acid residues that mediate substrate recognition in the lactose carrier of Escherichia coli. The lactose carrier transports the alpha-galactoside sugar melibiose as well as the beta-galactoside sugar lactose. Mutants from cells containing the lac genes on an F factor were selected by the ability to grow on succinate in the presence of the toxic galactoside beta-thio-o-nitrophenylgalactoside. Mutants that grew on melibiose minimal plates but failed to grow on lactose minimal plates were picked. In sugar transport assays, mutant cells showed the striking result of having low levels of lactose downhill transport but high levels of melibiose downhill transport. Accumulation (uphill) of melibiose was completely defective in all of the mutants. Kinetic analysis of melibiose transport in the mutants showed either no change or a greater than normal apparent affinity for melibiose. PCR was used to amplify the lacY DNA of each mutant, which was then sequenced by the Sanger method. The following six mutations were found in the lacY structural genes of individual mutants: Tyr-26-->Asp, Phe-27-->Tyr, Phe-29-->Leu, Asp-240-->Val, Leu-321-->Gln, and His-322-->Tyr. We conclude from these experiments that Tyr-26, Phe-27, Phe-29 (helix 1), Asp-240 (helix 7), Leu-321, and His-322 (helix 10) either directly or indirectly mediate sugar recognition in the lactose carrier of E. coli.

The discovery of slowness: low-capacity transport and slow anion channel gating by the glutamate transporter EAAT5.

PubMed

Gameiro, Armanda; Braams, Simona; Rauen, Thomas; Grewer, Christof

2011-06-08

Excitatory amino acid transporters (EAATs) control the glutamate concentration in the synaptic cleft by glial and neuronal glutamate uptake. Uphill glutamate transport is achieved by the co-/countertransport of Na(+) and other ions down their concentration gradients. Glutamate transporters also display an anion conductance that is activated by the binding of Na(+) and glutamate but is not thermodynamically coupled to the transport process. Of the five known glutamate transporter subtypes, the retina-specific subtype EAAT5 has the largest conductance relative to glutamate uptake activity. Our results suggest that EAAT5 behaves as a slow-gated anion channel with little glutamate transport activity. At steady state, EAAT5 was activated by glutamate, with a K(m)= 61 ± 11 μM. Binding of Na(+) to the empty transporter is associated with a K(m) = 229 ± 37 mM, and binding to the glutamate-bound form is associated with a K(m) = 76 ± 40 mM. Using laser-pulse photolysis of caged glutamate, we determined the pre-steady-state kinetics of the glutamate-induced anion current of EAAT5. This was characterized by two exponential components with time constants of 30 ± 1 ms and 200 ± 15 ms, which is an order of magnitude slower than those observed in other glutamate transporters. A voltage-jump analysis of the anion currents indicates that the slow activation behavior is caused by two slow, rate-limiting steps in the transport cycle, Na(+) binding to the empty transporter, and translocation of the fully loaded transporter. We propose a kinetic transport scheme that includes these two slow steps and can account for the experimentally observed data. Overall, our results suggest that EAAT5 may not act as a classical high-capacity glutamate transporter in the retina; rather, it may function as a slow-gated glutamate receptor and/or glutamate buffering system. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Hydrogeological characterization of shallow-depth zone for CO2 injection and leak test at a CO2 environmental monitoring site in Korea

NASA Astrophysics Data System (ADS)

Lee, S. S.; Kim, T. W.; Kim, H. H.; Ha, S. W.; Jeon, W. T.; Lee, K. K.

2015-12-01

The main goal of the this study is to evaluate the importance of heterogeneities in controlling the field-scale transport of CO2 are originated from the CO2 injected at saturated zone below the water table for monitoring and prediction of CO2 leakage from a reservoir. Hydrogeological and geophysical data are collected to characterize the site, prior to conducting CO2 injection experiment at the CO2 environmental monitoring site at Eumseong, Korea. The geophysical data were acquired from borehole electromagnetic flowmeter tests, while the hydraulic data were obtained from pumping tests, slug tests, and falling head permeability tests. Total of 13 wells to perform hydraulic and geophysical test are established along groundwater flow direction in regular sequence, revealed by the results of borehole electromagnetic flowmeter test. The results of geophysical tests indicated that hydraulic gradient is not identical with the topographic gradient. Groundwater flows toward the uphill direction in the study area. Then, the hydraulic tests were conducted to identify the hydraulic properties of the study site. According to the results of pumping and slug tests at the study site, the hydraulic conductivity values show ranges between 4.75 x 10-5 cm/day and 9.74 x 10-5 cm/day. In addition, a portable multi-level sampling and monitoring packer device which remains inflated condition for a long period developed and used to isolate designated depths to identify vertical distribution of hydrogeological characteristics. Hydrogeological information obtained from this study will be used to decide the injection test interval of CO2-infused water and gaseous CO2. Acknowledgement: Financial support was provided by "R&D Project on Environmental Mangement of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003).

A late Holocene pollen record from proglacial Oblong Tarn, Mount Kenya

PubMed Central

Gajewski, Konrad; Marchant, Rob; Rosqvist, Gunhild

2017-01-01

High-elevation ecosystems, such as those on Mount Kenya are undergoing significant changes, with accelerated glacial ice losses over the twentieth century creating new space for alpine plants to establish. These ecosystems respond rapidly to climatic variability and within decades of glacial retreat, Afroalpine pioneering taxa stabilize barren land and facilitate soil development, promoting complex patches of alpine vegetation. Periglacial lake sediment records can be used to examine centennial and millennial scale variations in alpine and montane vegetation compositions. Here we present a 5300-year composite pollen record from an alpine tarn (4370 m asl) in the Hausberg Valley of Mount Kenya. Overall, the record shows little apparent variation in the pollen assemblage through time with abundant montane forest taxa derived and transported from mid elevations, notably high abundances of aerophilous Podocarpus pollen. Afroalpine taxa included Alchemilla, Helichrysum and Dendrosenecio-type, reflecting local vegetation cover. Pollen from the ericaceous zone was present throughout the record and Poaceae percentages were high, similar to other high elevation pollen records from eastern Africa. The Oblong Tarn record pollen assemblage composition and abundances of Podocarpus and Poaceae since the late Holocene (~4000 cal yr BP-present) are similar to pollen records from mid-to-high elevation sites of nearby high mountains such as Mount Elgon and Kilimanjaro. These results suggest a significant amount of uphill pollen transport with only minor apparent variation in local taxa. Slight decreasing trends in alpine and ericaceous taxonomic groups show a long-term response to global late Holocene cooling and a step decrease in rate of change estimated from the pollen assemblages at 3100 cal yr BP in response to regional hydroclimatic variability. Changes in the principal component axis scores of the pollen assemblage were coherent with an independent mid-elevation temperature reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300–3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs. PMID:28926642

Uphill energy transfer from long-wavelength absorbing chlorophylls to PS II in Ostreobium sp. is functional in carbon assimilation.

PubMed

Wilhelm, Christian; Jakob, Torsten

2006-03-01

From the algal genus Ostrobium two species are known which express a chlorophyll antenna absorbing between 710 and 725 nm to a different extent. In a comparative study with these two species it is shown that quanta absorbed by this long wavelength antenna can be transferred to PS II leading to significant PS II-related electron transfer. It is documented that under monochromatic far red light illumination growth continues with rather high efficiency. The data show that the uphill-energy transfer to PS II reduces the quantum yield under white light significantly. It is discussed that this strategy of energy conversion might play a role in special environments where far red light is the predominant energy source.

A hierarchical transition state search algorithm

NASA Astrophysics Data System (ADS)

del Campo, Jorge M.; Köster, Andreas M.

2008-07-01

A hierarchical transition state search algorithm is developed and its implementation in the density functional theory program deMon2k is described. This search algorithm combines the double ended saddle interpolation method with local uphill trust region optimization. A new formalism for the incorporation of the distance constrain in the saddle interpolation method is derived. The similarities between the constrained optimizations in the local trust region method and the saddle interpolation are highlighted. The saddle interpolation and local uphill trust region optimizations are validated on a test set of 28 representative reactions. The hierarchical transition state search algorithm is applied to an intramolecular Diels-Alder reaction with several internal rotors, which makes automatic transition state search rather challenging. The obtained reaction mechanism is discussed in the context of the experimentally observed product distribution.

Studies on the lithium transport across the red cell membrane. II. Characterization of ouabain-sensitive and ouabain-insensitive Li+ transport. Effects of bicarbonate and dipyridamole.

PubMed

Duhm, J; Becker, B F

1977-01-17

In studies on Li+ net-transport across the human red cell membrane following results were obtained: 1. In K+- and Na+-free choline chloride media, Li+ is transported into the erythrocytes against an electrochemical gradient. This Li+ uphill transport as well as Li+ downhill transport into the cells is inhibited by ouabain, ATP-depletion, and by external K+ and Na+. The effects of K+ and Na+ are relieved at high Li+ concentrations. 2. Ouabain-sensitive Li+ uptake, determined at 10 mM external Na+, does not obey simple Michaelis-Menten kinetics and exhibits a maximum at about pH 7. 3. Ouabain-resistant Li+ downhill transport into erythrocytes increases with rising pH. It is comprised of a saturating component and a component linearly dependent on external Li+. The linear component is partly inhibited by dipyridamole and accelerated by bicarbonate. The bicarbonate effect can be completely blocked by dipyridamole, phlorizin and phenylbutazone. 4. Li+ release is not inhibited by ouabain, ATP-depletion and external K+. It increases with external Na+ concentration, tending to saturate at 150 mM Na+. Na+-independent Li+ release is stimulated by bicarbonate. It is concluded that ouabain-sensitive Li+ uptake is mediated at the K+-site(s) of the Na+-K+ pump. Li+, K+ and Na+ appear to compete for a common site (or sites). The stimulation of Li+ transfer by bicarbonate and the inhibition by dipyridamole suggest a participation of anionic species in ouabain-resistant Li+ transfer. The Na+-dependent Li+ release and the "saturating component" of Li+ uptake are ascribed to the Na+-dependent Li+ countertransport system.

Review of samples of water, sediment, tailings, and biota at the Little Bonanza mercury mine, San Luis Obispo County, California

USGS Publications Warehouse

Rytuba, James J.; Hothem, Roger L.; Goldstein, Daniel N.; Brussee, Brianne E.; May, Jason T.

2011-01-01

Sample Sites and Methods Samples were collected to assess the concentrations of Hg and biogeochemically relevant constituents in tailings and wasterock piles at the Little Bonanza Hg mine. Tailings are present adjacent to a three-pipe retort used to process the Hg ore. The tailings occur in the upper 15 cm of the soil adjacent to the retort and slag from the retort is present on the surface. An area of disturbed soil and rock uphill from the retort was likely formed during construction of a dam that provided water for mining activities. Wasterock in these piles was sampled. The largest amount of tailings is exposed to the west of the retort in the bank of WF Las Tablas Creek. Water, sediment, and biota were sampled from WF Las Tablas Creek, which flows through the mine area. Sample-site locations are shown in figures 10 and 11 and listed in table 1. Samples were collected when streamflow was low and no precipitation had occurred.

Give your heart a workout

MedlinePlus

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Muscle coordination in cycling: effect of surface incline and posture.

PubMed

Li, L; Caldwell, G E

1998-09-01

The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.

Diffusive exchange of trace elements between alkaline melts: Implications for element fractionation and timescale estimations during magma mixing

NASA Astrophysics Data System (ADS)

González-Garcia, Diego; Petrelli, Maurizio; Behrens, Harald; Vetere, Francesco; Fischer, Lennart A.; Morgavi, Daniele; Perugini, Diego

2018-07-01

The diffusive exchange of 30 trace elements (Cs, Rb, Ba, Sr, Co, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, V, Cr, Pb, Th, U, Zr, Hf, Sn and Nb) during the interaction of natural mafic and silicic alkaline melts was experimentally studied at conditions relevant to shallow magmatic systems. In detail, a set of 12 diffusion couple experiments have been performed between natural shoshonitic and rhyolitic melts from the Vulcano Island (Aeolian archipelago, Italy) at a temperature of 1200 °C, pressures from 50 to 500 MPa, and water contents ranging from nominally dry to ca. 2 wt.%. Concentration-distance profiles, measured by Laser Ablation ICP-MS, highlight different behaviours, and trace elements were divided into two groups: (1) elements with normal diffusion profiles (13 elements, mainly low field strength and transition elements), and (2) elements showing uphill diffusion (17 elements including Y, Zr, Nb, Pb and rare earth elements, except Eu). For the elements showing normal diffusion profiles, chemical diffusion coefficients were estimated using a concentration-dependent evaluation method, and values are given at four intermediate compositions (SiO2 equal to 58, 62, 66 and 70 wt.%, respectively). A general coupling of diffusion coefficients to silica diffusivity is observed, and variations in systematics are observed between mafic and silicic compositions. Results show that water plays a decisive role on diffusive rates in the studied conditions, producing an enhancement between 0.4 and 0.7 log units per 1 wt.% of added H2O. Particularly notable is the behaviour of the trivalent-only REEs (La to Nd and Gd to Lu), with strong uphill diffusion minima, diminishing from light to heavy REEs. Modelling of REE profiles by a modified effective binary diffusion model indicates that activity gradients induced by the SiO2 concentration contrast are responsible for their development, inducing a transient partitioning of REEs towards the shoshonitic melt. These results indicate that diffusive fractionation of trace elements is possible during magma mixing events, especially in the more silicic melts, and that the presence of water in such events can lead to enhanced chemical diffusive mixing efficiency, affecting also the estimation of mixing to eruption timescales.

FLYING-WATER Renewables-H2-H2O TERRAFORMING: PERMANENT Drought(s)-Elimination FOREVER!!!

NASA Astrophysics Data System (ADS)

Lyons, M.; Siegel, E.

2010-03-01

``Water water everywhere; ne'er a drop to drink''[Coleridg(1798)]; now:``Hydrogen hydrogen everywhere;STILL ne'er a drop to drink'': ONLY H2 can be ``FLYING-WATER''/``chemical-rain-in-pipelines''/ ``Hindenberg-effect (H2-UP;H2O-DOWN): atomic-weights ratio: O/H2O=[16]/[18]˜90%; O already in air uphill; NO H2O pumping need! In water-starved glacial-melting world, rescue ONLY by Siegel[3rd Intl.Conf.Alt.Energy,Hemisphere/Springer(1980)- vol.5/ p.459]Renewables-H2-H2O purposely flexible versatile agile customizable scaleable retrofitable integrated operating- system. Rosenfeld[Sci.315,1396(3/9/2007)]-Biello[Sci.Am.(3/9/ 2007)]crucial geomorphology which ONLY maximal-buoyancy light- est-element H2 can exploit, to again make ``Mountains into Fount- ains": Siegel ``terra-forming''(and ocean-rebasificaton!!!) long pre-``Holdren''-``Ciccerine" ``geo-enginering'', only via Siegel proprietary magnetic-hydrogen-valve permits H2 flow in already in-ground dense BCC/ferritic-steels pipelines-network (NO new infrastructure) counters Tromp[Sci.300,1740(03)]global-pandemics (cancers/blindness/famine)dire-warning about H2-(ALONE)economy CATASTROPHIC H2 ozone-layer destruction sobering cavat to dangerous H2-automotion-economy panacea hype!

Microscopic models for uphill diffusion

NASA Astrophysics Data System (ADS)

Colangeli, Matteo; De Masi, Anna; Presutti, Errico

2017-10-01

We study a system of particles which jump on the sites of the interval [1, L] of { Z} . The density at the boundaries is kept fixed to simulate the action of mass reservoirs. The evolution depends on two parameters \

Can variation in risk of nest predation explain altitudinal migration in tropical birds?

PubMed

Boyle, W Alice

2008-03-01

Migration is among the best studied of animal behaviors, yet few empirical studies have tested hypotheses explaining the ultimate causes of these cyclical annual movements. Fretwell's (1980) hypothesis predicts that if nest predation explains why many tropical birds migrate uphill to breed, then predation risk must be negatively associated with elevation. Data from 385 artificial nests spanning 2,740 m of elevation on the Atlantic slope of Costa Rica show an overall decline in predation with increasing elevation. However, nest predation risk was highest at intermediate elevations (500-650 m), not at lowest elevations. The proportion of nests depredated by different types of predators differed among elevations. These results imply that over half of the altitudinal migrant bird species in this region migrate to safer breeding areas than their non-breeding areas, suggesting that variation in nest predation risk could be an important benefit of uphill migrations of many species.

Energy cost and lower leg muscle activities during erect bipedal locomotion under hyperoxia.

PubMed

Abe, Daijiro; Fukuoka, Yoshiyuki; Maeda, Takafumi; Horiuchi, Masahiro

2018-06-19

Energy cost of transport per unit distance (CoT) against speed shows U-shaped fashion in walking and linear fashion in running, indicating that there exists a specific walking speed minimizing the CoT, being defined as economical speed (ES). Another specific gait speed is the intersection speed between both fashions, being called energetically optimal transition speed (EOTS). We measured the ES, EOTS, and muscle activities during walking and running at the EOTS under hyperoxia (40% fraction of inspired oxygen) on the level and uphill gradients (+ 5%). Oxygen consumption [Formula: see text] and carbon dioxide output [Formula: see text] were measured to calculate the CoT values at eight walking speeds (2.4-7.3 km h -1 ) and four running speeds (7.3-9.4 km h - 1 ) in 17 young males. Electromyography was recorded from gastrocnemius medialis, gastrocnemius lateralis (GL), and tibialis anterior (TA) to evaluate muscle activities. Mean power frequency (MPF) was obtained to compare motor unit recruitment patterns between walking and running. [Formula: see text], [Formula: see text], and CoT values were lower under hyperoxia than normoxia at faster walking speeds and any running speeds. A faster ES on the uphill gradient and slower EOTS on both gradients were observed under hyperoxia than normoxia. GL and TA activities became lower when switching from walking to running at the EOTS under both FiO 2 conditions on both gradients, so did the MPF in the TA. ES and EOTS were influenced by reduced metabolic demands induced by hyperoxia. GL and TA activities in association with a lower shift of motor unit recruitment patterns in the TA would be related to the gait selection when walking or running at the EOTS. UMIN000017690 ( R000020501 ). Registered May 26, 2015, before the first trial.

Accuracy of indirect estimation of power output from uphill performance in cycling.

PubMed

Millet, Grégoire P; Tronche, Cyrille; Grappe, Frédéric

2014-09-01

To use measurement by cycling power meters (Pmes) to evaluate the accuracy of commonly used models for estimating uphill cycling power (Pest). Experiments were designed to explore the influence of wind speed and steepness of climb on accuracy of Pest. The authors hypothesized that the random error in Pest would be largely influenced by the windy conditions, the bias would be diminished in steeper climbs, and windy conditions would induce larger bias in Pest. Sixteen well-trained cyclists performed 15 uphill-cycling trials (range: length 1.3-6.3 km, slope 4.4-10.7%) in a random order. Trials included different riding position in a group (lead or follow) and different wind speeds. Pmes was quantified using a power meter, and Pest was calculated with a methodology used by journalists reporting on the Tour de France. Overall, the difference between Pmes and Pest was -0.95% (95%CI: -10.4%, +8.5%) for all trials and 0.24% (-6.1%, +6.6%) in conditions without wind (<2 m/s). The relationship between percent slope and the error between Pest and Pmes were considered trivial. Aerodynamic drag (affected by wind velocity and orientation, frontal area, drafting, and speed) is the most confounding factor. The mean estimated values are close to the power-output values measured by power meters, but the random error is between ±6% and ±10%. Moreover, at the power outputs (>400 W) produced by professional riders, this error is likely to be higher. This observation calls into question the validity of releasing individual values without reporting the range of random errors.

The influence of incline and speed on work rate, gross efficiency and kinematics of roller ski skating.

PubMed

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2012-08-01

During competitions, elite cross-country skiers produce higher external work rates on uphill than on flat terrain. However, it is not presently known whether this reflects solely higher energy expenditure. Furthermore, the kinematic factors associated with these higher rates of uphill work have not yet been examined. Therefore, in the present investigation the work rate and associated kinematic parameters at similar metabolic rates during roller ski skating on flat and uphill terrains have been compared. Seven elite male skiers performed six 5-min sub-maximal exercise bouts at the same low, moderate and high metabolic rates on 2 and 8% inclines, while roller skiing on a treadmill employing the G3 skating technique. The work rate was calculated as work against gravity and friction, whereas the energetic equivalent of VO(2) was taken as the metabolic rate. Gross efficiency was defined as work rate divided by metabolic rate. Kinematic parameters were analyzed in three dimensions. At the same metabolic rate, the work rate, cycle rate, work per cycle and relative duration of propulsive phases during a cycle of movement were all higher on the 8% than on the 2% incline at all speeds (all P < 0.05). At similar work rates, gross efficiency was greater on the 8% incline (P < 0.05). In conclusion, these elite skiers consistently demonstrated higher work rates on the 8% incline. To achieve the higher work rates on the steeper incline, these elite skiers employed higher cycle rates and performed more work per cycle, in association with a longer relative propulsive phase.

Effect of walking speed on lower extremity joint loading in graded ramp walking.

PubMed

Schwameder, Hermann; Lindenhofer, Elke; Müller, Erich

2005-07-01

Lower extremity joint loading during walking is strongly affected by the steepness of the slope and might cause pain and injuries in lower extremity joint structures. One feasible measure to reduce joint loading is the reduction of walking speed. Positive effects have been shown for level walking, but not for graded walking or hiking conditions. The aim of the study was to quantify the effect of walking speed (separated into the two components, step length and cadence) on the joint power of the hip, knee and ankle and to determine the knee joint forces in uphill and downhill walking. Ten participants walked up and down a ramp with step lengths of 0.46, 0.575 and 0.69 m and cadences of 80, 100 and 120 steps per minute. The ramp was equipped with a force platform and the locomotion was filmed with a 60 Hz video camera. Loading of the lower extremity joints was determined using inverse dynamics. A two-dimensional knee model was used to calculate forces in the knee structures during the stance phase. Walking speed affected lower extremity joint loading substantially and significantly. Change of step length caused much greater loading changes for all joints compared with change of cadence; the effects were more distinct in downhill than in uphill walking. The results indicate that lower extremity joint loading can be effectively controlled by varying step length and cadence during graded uphill and downhill walking. Hikers can avoid or reduce pain and injuries by reducing walking speed, particularly in downhill walking.

Effects of prolonged strenuous endurance exercise on plasma myosin heavy chain fragments and other muscular proteins. Cycling vs running.

PubMed

Koller, A; Mair, J; Schobersberger, W; Wohlfarter, T; Haid, C; Mayr, M; Villiger, B; Frey, W; Puschendorf, B

1998-03-01

This study evaluates creatine kinase, myosin heavy chain, and cardiac troponin blood levels following three types of exercise: 1) short-distance uphill or downhill running; 2) alpine ultramarathon; and 3) alpine long-distance cycling. Comparative field study; follow-up up to 10 days. Department of Sports Medicine. All biochemical markers were analysed at the Department of Medical Chemistry and Biochemistry. Subjects included healthy, trained males (N = 53). All subjects were nonsmokers and free from medication prior to and during the study. Each volunteer was an experienced runner or cyclist, who had at least once successfully finished the Swiss Alpine Marathon of Davos or the Otztal-Radmarathon before. Running or cycling. Plasma concentrations of creatine kinase, myosin heavy chain fragments and cardiac troponins were measured to diagnose skeletal and cardiac muscle damage, respectively. Skeletal muscle protein release is markedly different between uphill and downhill running, with very little evidence for muscle damage in the uphill runners. There is considerable muscle protein leakage in the ultramarathoners (67 km distance; 30 km downhill running). In contrast, only modest amounts of skeletal muscle damage are found after alpine long-distance cycling (230 km distance). This study proves that there is slow-twitch skeletal muscle fiber damage after prolonged strenuous endurance exercise and short-distance downhill running. Exhaustive endurance exercise involving downhill running and short-distance downhill running lead to more pronounced injury than strenuous endurance exercise involving concentric actions. From our results there is no reason for suggesting that prolonged intense exercise may induce myocardial injury in symptom-less athletes without cardiac deseases.

Achilles tendon rupture - aftercare

MedlinePlus

... to go from walking to running, or to running uphill Tripped and fell, or had another accident Played a sport like tennis or basketball, with a lot of stopping and sharp turns Most injuries can be diagnosed during a physical exam. You ...

Certainty is Illusion: The Myth of Strategic Guidance

DTIC Science & Technology

2015-06-21

faced an uphill battle with the British. Outlining the American position, Eisenhower wrote that Gymnast was “strategically unsound as an operation...Certainty is Illusion: The Myth of Strategic Guidance A Monograph by Lieutenant Colonel Matthew C. Gaetke United States...

5. View, oxidizer waste tanks and containment basin in foreground ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. View, oxidizer waste tanks and containment basin in foreground with Systems Integration Laboratory (T-28) uphill in background, looking northeast. - Air Force Plant PJKS, Systems Integration Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Length-Displacement Scaling of Lunar Thrust Faults and the Formation of Uphill-Facing Scarps

NASA Astrophysics Data System (ADS)

Hiesinger, Harald; Roggon, Lars; Hetzel, Ralf; Clark, Jaclyn D.; Hampel, Andrea; van der Bogert, Carolyn H.

2017-04-01

Lobate scarps are straight to curvilinear positive-relief landforms that occur on all terrestrial bodies [e.g., 1-3]. They are the surface manifestation of thrust faults that cut through and offset the upper part of the crust. Fault scarps on planetary surfaces provide the opportunity to study the growth of faults under a wide range of environmental conditions (e.g., gravity, temperature, pore pressure) [4]. We studied four lunar thrust-fault scarps (Simpelius-1, Morozov (S1), Fowler, Racah X-1) ranging in length from 1.3 km to 15.4 km [5] and found that their maximum total displacements are linearly correlated with length over one order of magnitude. We propose that during the progressive accumulation of slip, lunar faults propagate laterally and increase in length. On the basis of our measurements, the ratio of maximum displacement, D, to fault length, L, ranges from 0.017 to 0.028 with a mean value of 0.023 (or 2.3%). This is an order of magnitude higher than the value of 0.1% derived by theoretical considerations [4], and about twice as large as the value of 0.012-0.013 estimated by [6,7]. Our results, in addition to recently published findings for other lunar scarps [2,8], indicate that the D/L ratios of lunar thrust faults are similar to those of faults on Mercury and Mars (e.g., 1, 9-11], and almost as high as the average D/L ratio of 3% for faults on Earth [16,23]. Three of the investigated thrust fault scarps (Simpelius-1, Morozov (S1), Fowler) are uphill-facing scarps generated by slip on faults that dip in the same direction as the local topography. Thrust faults with such a geometry are common ( 60% of 97 studied scarps) on the Moon [e.g., 2,5,7]. To test our hypothesis that the surface topography plays an important role in the formation of uphill-facing fault scarps by controlling the vertical load on a fault plane, we simulated thrust faulting and its relation to topography with two-dimensional finite-element models using the commercial code ABAQUS (version 6.14). Our model results indicate that the onset of faulting in our 200-km-long model is a function of the surface topography [5]. Our numerical model indicates that uphill-facing scarps form earlier and grow faster than downhill-facing scarps under otherwise similar conditions. Thrust faults which dip in the same general direction as the topography (forming an uphill-facing scarp), start to slip earlier (4.2 Ma) after the onset of shortening and reach a total slip of 5.8 m after 70 Ma. In contrast, slip on faults that leads to the generation of a downhill-facing scarp initiates much later (i.e., after 20 Ma of elapsed model time) and attains a total slip of only 1.8 m in 70 Ma. If the surface of the model is horizontal, faulting on both fault structures starts after 4.4 Ma, but faulting proceeds at a lower rate than for fault, which generated the uphill-facing scarp. Although the absolute ages for fault initiation (as well as the total fault slip) depend on the arbitrarily chosen shortening rate (as well as on the size of the model and the elastic parameters), this relative timing of fault activation was consistently observed irrespective of the chosen shortening rate. Thus, the model results demonstrate that, for all other factors being equal, the differing weight of the hanging wall above the two modeled faults is responsible for the different timing of fault initiation and the difference in total slip. In conclusion, we present new quantitative estimates of the maximum total displacements of lunar lobate scarps and offer a new model to explain the origin of uphill-facing scarps that is also of importance for understanding the formation of the Lee-Lincoln scarp at the Apollo 17 landing site. [1] Watters et al., 2000, Geophys. Res. Lett. 27; [2] Williams et al., 2013, J. Geophys. Res. 118; [3] Massironi et al., 2015, Encycl. Planet. Landf., pp. 1255-1262; [4] Schultz et al., 2006, J. Struct. Geol. 28; [5] Roggon et al. (2017) Icarus, in press; [6] Watters and Johnson, 2010, Planetary Tectonics, pp. 121-182; [7] Banks et al., 2012, J. Geophys. Res. 117; [8] Banks et al., 2013, LPSC 44, 3042; [9] Hauber and Kronberg, 2005, J. Geophys. Res. 110; [10] Hauber et al., 2013, EPSC2013-987; [11] Byrne et al., 2014, Nature Geosci. 7

Lower limb joint work and joint work contribution during downhill and uphill walking at different inclinations.

PubMed

Alexander, Nathalie; Strutzenberger, Gerda; Ameshofer, Lisa Maria; Schwameder, Hermann

2017-08-16

Work performance and individual joint contribution to total work are important information for creating training protocols, but were not assessed so far for sloped walking. Therefore, the purpose of this study was to analyze lower limb joint work and joint contribution of the hip, knee and ankle to total lower limb work during sloped walking in a healthy population. Eighteen male participants (27.0±4.7yrs, 1.80±0.05m, 74.5±8.2kg) walked on an instrumented ramp at inclination angles of 0°, ±6°, ±12° and ±18° at 1.1m/s. Kinematic and kinetic data were captured using a motion-capture system (Vicon) and two force plates (AMTI). Joint power curves, joint work (positive, negative, absolute) and each joint's contribution to total lower limb work were analyzed throughout the stance phase using an ANOVA with repeated measures. With increasing inclination positive joint work increased for the ankle and hip joint and in total during uphill walking. Negative joint work increased for each joint and in total work during downhill walking. Absolute work was increased during both uphill (all joints) and downhill (ankle & knee) walking. Knee joint contribution to total negative and absolute work increased during downhill walking while hip and ankle contributions decreased. This study identified, that, when switching from level to a 6° and from 6° to a 12° inclination the gain of individual joint work is more pronounced compared to switching from 12° to an 18° inclination. The results might be used for training recommendations and specific training intervention with respect to sloped walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Near-Infrared Spectroscopy: More Accurate Than Heart Rate for Monitoring Intensity in Running in Hilly Terrain.

PubMed

Born, Dennis-Peter; Stöggl, Thomas; Swarén, Mikael; Björklund, Glenn

2017-04-01

To investigate the cardiorespiratory and metabolic response of trail running and evaluate whether heart rate (HR) adequately reflects the exercise intensity or if the tissue-saturation index (TSI) could provide a more accurate measure during running in hilly terrain. Seventeen competitive runners (4 women, V̇O 2 max, 55 ± 6 mL · kg -1 · min -1 ; 13 men, V̇O 2 max, 68 ± 6 mL · kg -1 · min -1 ) performed a time trial on an off-road trail course. The course was made up of 2 laps covering a total distance of 7 km and included 6 steep uphill and downhill sections with an elevation gain of 486 m. All runners were equipped with a portable breath-by-breath gas analyzer, HR belt, global positioning system receiver, and near-infrared spectroscopy (NIRS) device to measure the TSI. During the trail run, the exercise intensity in the uphill and downhill sections was 94% ± 2% and 91% ± 3% of maximal heart rate, respectively, and 84% ± 8% and 68% ± 7% of V̇O 2 max, respectively. The oxygen uptake (V̇O 2 ) increased in the uphill sections and decreased in the downhill sections (P < .01). Although HR was unaffected by the altering slope conditions, the TSI was inversely correlated to the changes in V̇O 2 (r = -.70, P < .05). HR was unaffected by the continuously changing exercise intensity; however, TSI reflected the alternations in V̇O 2 . Recently used exclusively for scientific purposes, this NIRS-based variable may offer a more accurate alternative than HR to monitor running intensity in the future, especially for training and competition in hilly terrain.

Comparison of particle mass and solid particle number (SPN) emissions from a heavy-duty diesel vehicle under on-road driving conditions and a standard testing cycle.

PubMed

Zheng, Zhongqing; Durbin, Thomas D; Xue, Jian; Johnson, Kent C; Li, Yang; Hu, Shaohua; Huai, Tao; Ayala, Alberto; Kittelson, David B; Jung, Heejung S

2014-01-01

It is important to understand the differences between emissions from standard laboratory testing cycles and those from actual on-road driving conditions, especially for solid particle number (SPN) emissions now being regulated in Europe. This study compared particle mass and SPN emissions from a heavy-duty diesel vehicle operating over the urban dynamometer driving schedule (UDDS) and actual on-road driving conditions. Particle mass emissions were calculated using the integrated particle size distribution (IPSD) method and called MIPSD. The MIPSD emissions for the UDDS and on-road tests were more than 6 times lower than the U.S. 2007 heavy-duty particulate matter (PM) mass standard. The MIPSD emissions for the UDDS fell between those for the on-road uphill and downhill driving. SPN and MIPSD measurements were dominated by nucleation particles for the UDDS and uphill driving and by accumulation mode particles for cruise and downhill driving. The SPN emissions were ∼ 3 times lower than the Euro 6 heavy-duty SPN limit for the UDDS and downhill driving and ∼ 4-5 times higher than the Euro 6 SPN limit for the more aggressive uphill driving; however, it is likely that most of the "solid" particles measured under these conditions were associated with a combination release of stored sulfates and enhanced sulfate formation associated with high exhaust temperatures, leading to growth of volatile particles into the solid particle counting range above 23 nm. Except for these conditions, a linear relationship was found between SPN and accumulation mode MIPSD. The coefficient of variation (COV) of SPN emissions of particles >23 nm ranged from 8 to 26% for the UDDS and on-road tests.

How do ants make sense of gravity? A Boltzmann Walker analysis of Lasius niger trajectories on various inclines.

PubMed

Khuong, Anaïs; Lecheval, Valentin; Fournier, Richard; Blanco, Stéphane; Weitz, Sébastian; Bezian, Jean-Jacques; Gautrais, Jacques

2013-01-01

The goal of this study is to describe accurately how the directional information given by support inclinations affects the ant Lasius niger motion in terms of a behavioral decision. To this end, we have tracked the spontaneous motion of 345 ants walking on a 0.5×0.5 m plane canvas, which was tilted with 5 various inclinations by [Formula: see text] rad ([Formula: see text] data points). At the population scale, support inclination favors dispersal along uphill and downhill directions. An ant's decision making process is modeled using a version of the Boltzmann Walker model, which describes an ant's random walk as a series of straight segments separated by reorientation events, and was extended to take directional influence into account. From the data segmented accordingly ([Formula: see text] segments), this extension allows us to test separately how average speed, segments lengths and reorientation decisions are affected by support inclination and current walking direction of the ant. We found that support inclination had a major effect on average speed, which appeared approximately three times slower on the [Formula: see text] incline. However, we found no effect of the walking direction on speed. Contrastingly, we found that ants tend to walk longer in the same direction when they move uphill or downhill, and also that they preferentially adopt new uphill or downhill headings at turning points. We conclude that ants continuously adapt their decision making about where to go, and how long to persist in the same direction, depending on how they are aligned with the line of maximum declivity gradient. Hence, their behavioral decision process appears to combine klinokinesis with geomenotaxis. The extended Boltzmann Walker model parameterized by these effects gives a fair account of the directional dispersal of ants on inclines.

The effect of mountain bike suspensions on vibrations and off-road uphill performance.

PubMed

Faiss, R; Praz, M; Meichtry, A; Gobelet, C; Deriaz, O

2007-06-01

This study evaluates the effect of front suspension (FS) and dual suspension (DS) mountain-bike on performance and vibrations during off-road uphill riding. Thirteen male cyclists (27+/-5 years, 70+/-6 kg, VO(2max)59+/-6 mL.kg(-1).min(-1), mean+/-SD) performed, in a random sequence, at their lactate threshold, an off-road uphill course (1.69 km, 212 m elevation gain) with both type of bicycles. Variable measured: a) VO(2) consumption (K4b2 analyzer, Cosmed), b) power output (SRM) c) gain in altitude and d) 3-D accelerations under the saddle and at the wheel (Physilog, EPFL, Switzerland). Power spectral analy- sis (Fourier) was performed from the vertical acceleration data. Respectively for the FS and DS mountain bike: speed amounted to 7.5+/-0.7 km.h(-1) and 7.4+/-0.8 km.h(-1), (NS), energy expenditure 1.39+/-0.16 kW and 1.38+/-0.18, (NS), gross efficiency 0.161+/-0.013 and 0.159+/-0.013, (NS), peak frequency of vibration under the saddle 4.78+/-2.85 Hz and 2.27+/-0.2 Hz (P<0.01) and median-frequency of vertical displacements of the saddle 9.41+/-1.47 Hz and 5.78+/-2.27 Hz (P<0.01). Vibrations at the saddle level of the DS bike are of low frequencies whereas those of the FS bike are mostly of high frequencies. In the DS bike, the torque produced by the cyclist at the pedal level may generate low frequency vibrations. We conclude that the DS bike absorbs more high frequency vibrations, is more comfortable and performs as well as the FS bicycle.

How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines

PubMed Central

Khuong, Anaïs; Lecheval, Valentin; Fournier, Richard; Blanco, Stéphane; Weitz, Sébastian; Bezian, Jean-Jacques; Gautrais, Jacques

2013-01-01

The goal of this study is to describe accurately how the directional information given by support inclinations affects the ant Lasius niger motion in terms of a behavioral decision. To this end, we have tracked the spontaneous motion of 345 ants walking on a 0.5×0.5 m plane canvas, which was tilted with 5 various inclinations by rad ( data points). At the population scale, support inclination favors dispersal along uphill and downhill directions. An ant's decision making process is modeled using a version of the Boltzmann Walker model, which describes an ant's random walk as a series of straight segments separated by reorientation events, and was extended to take directional influence into account. From the data segmented accordingly ( segments), this extension allows us to test separately how average speed, segments lengths and reorientation decisions are affected by support inclination and current walking direction of the ant. We found that support inclination had a major effect on average speed, which appeared approximately three times slower on the incline. However, we found no effect of the walking direction on speed. Contrastingly, we found that ants tend to walk longer in the same direction when they move uphill or downhill, and also that they preferentially adopt new uphill or downhill headings at turning points. We conclude that ants continuously adapt their decision making about where to go, and how long to persist in the same direction, depending on how they are aligned with the line of maximum declivity gradient. Hence, their behavioral decision process appears to combine klinokinesis with geomenotaxis. The extended Boltzmann Walker model parameterized by these effects gives a fair account of the directional dispersal of ants on inclines. PMID:24204636

(Virtual) Water Flows Uphill toward Money.

PubMed

Wang, Ranran; Hertwich, Edgar; Zimmerman, Julie B

2016-11-15

This study provides a more precise understanding of the main driving forces of anthropogenic water use across countries. The anthropogenic water use was distinguished as blue water (i.e., fresh surface and groundwater) and total water (i.e. blue + green water; green water is rainwater insofar as it does not become runoff) used for producing, consuming, exporting, and importing of primary and manufactured goods and services, measured on a per country and per capita basis. The population effect on national blue water consumption associated with producing and consuming was found to be bigger than what the commonly assumed unitary population elasticity indicates. Distinct from the homogeneous affluence-water relationships conventionally assumed, this study revealed varying and potentially opposite effects affluence can have depending on the water use account of interest (e.g., production-based or consumption-based, blue or green) and the income level. Affluence, not the availability of freshwater resources, was found to be the most critical driver of virtual water imports. And a more affluent lifestyle in high-income countries was still associated with greater blue water consumption. With each doubling of income, blue water embedded in the goods and services a nation consumed and imported on a per capita basis increased by 82% and 86%, respectively, across the 110 countries analyzed for 2007. In comparison to affluence, the varying per capita water consumption accounts across the nations were much less sensitive to food consumption patterns. Given its critical role for water, land, and energy use shown by this and previous studies, affluence should be taken as a critical factor in future studies to better understand and leverage the water-energy-food-land nexus.

Conductivity gradients as inferred by electromagnetic-induction meter (EM38) readings within a salt-affected wetland in Saskatchewan, Canada

NASA Astrophysics Data System (ADS)

Mirck, Jaconette; Schroeder, William

2018-01-01

The change from deep-rooted grass and shrub vegetation to annual-cropping dryland farming has contributed to serious soil salinization challenges on the semi-arid North American Great Plains. In some cases, cultivation of the Great Plains has increased the availability of water, causing dominant sulfate salts to travel from the uphill areas to depressions where it will surface when water evaporates at the soil surface. A potential solution could include the replanting of the native deep-rooted vegetation, which requires knowledge of the spatial distribution of soil salinity. This study tested the soil factors influencing electromagnetic-induction meter (EM38) readings of soil salinity distribution around wetlands. The objectives were to: (1) predict growth and survival of Salix dasyclados Wimm. (cv. `India') along a salinity gradient in a small wetland, and (2) investigate whether newly established willows affected water-table fluctuations, which would indicate their phreatophytic nature or their ability to obtain their water supply from the zone of saturation. Results indicated significantly lower salinity values for sampling points with EM38 readings above 175 and 250 mS m-1 for height and survival, respectively. In addition, diurnal fluxes of the water table in areas of good willow growth and lower salinity indicated that cultivar `India' was phreatophytic in these areas and therefore has great potential for being used to combat saline seeps.

Conductivity gradients as inferred by electromagnetic-induction meter (EM38) readings within a salt-affected wetland in Saskatchewan, Canada

NASA Astrophysics Data System (ADS)

Mirck, Jaconette; Schroeder, William

2018-06-01

The change from deep-rooted grass and shrub vegetation to annual-cropping dryland farming has contributed to serious soil salinization challenges on the semi-arid North American Great Plains. In some cases, cultivation of the Great Plains has increased the availability of water, causing dominant sulfate salts to travel from the uphill areas to depressions where it will surface when water evaporates at the soil surface. A potential solution could include the replanting of the native deep-rooted vegetation, which requires knowledge of the spatial distribution of soil salinity. This study tested the soil factors influencing electromagnetic-induction meter (EM38) readings of soil salinity distribution around wetlands. The objectives were to: (1) predict growth and survival of Salix dasyclados Wimm. (cv. `India') along a salinity gradient in a small wetland, and (2) investigate whether newly established willows affected water-table fluctuations, which would indicate their phreatophytic nature or their ability to obtain their water supply from the zone of saturation. Results indicated significantly lower salinity values for sampling points with EM38 readings above 175 and 250 mS m-1 for height and survival, respectively. In addition, diurnal fluxes of the water table in areas of good willow growth and lower salinity indicated that cultivar `India' was phreatophytic in these areas and therefore has great potential for being used to combat saline seeps.

Development of a model to predict ash transport and water pollution risk in fire-affected environments

NASA Astrophysics Data System (ADS)

Neris, Jonay; Elliot, William J.; Doerr, Stefan H.; Robichaud, Peter R.

2017-04-01

An estimated that 15% of the world's population lives in volcanic areas. Recent catastrophic erosion events following wildfires in volcanic terrain have highlighted the geomorphological instability of this soil type under disturbed conditions and steep slopes. Predicting the hydrological and erosional response of this soils in the post-fire period is the first step to design and develop adequate actions to minimize risks in the post-fire period. In this work we apply, for the first time, the Water Erosion Prediction Project model for predicting erosion and runoff events in fire-affected volcanic soils in Europe. Two areas affected by wildfires in 2015 were selected in Tenerife (Spain) representative of different fire behaviour (downhill surface fire with long residence time vs uphill crown fire with short residence time), severity (moderate soil burn severity vs light soil burn severity) and climatic conditions (average annual precipitation of 750 and 210 mm respectively). The actual erosion processes were monitored in the field using silt fences. Rainfall and rill simulations were conducted to determine hydrologic, interrill and rill erosion parameters. The soils were sampled and key properties used as model input, evaluated. During the first 18 months after the fire 7 storms produced runoff and erosion in the selected areas. Sediment delivery reached 5.4 and 2.5 Mg ha-1 respectively in the first rainfall event monitored after the fire, figures comparable to those reported for fire-affected areas of the western USA with similar climatic conditions but lower than those showed by wetter environments. The validation of the WEPP model using field data showed reasonable estimates of hillslope sediment delivery in the post-fire period and, therefore, it is suggested that this model can support land managers in volcanic areas in Europe in predicting post-fire hydrological and erosional risks and designing suitable mitigation treatments.

The Uphill Climb

ERIC Educational Resources Information Center

Stewart, Pearl

2012-01-01

Despite decades of research and recommendations, a revolving door continues to cycle Black and Hispanic faculty into and out of predominantly White higher education institutions. Interviews with the scholars and researchers who have examined this issue in recent years suggest that, although some institutions have ramped up their recruitment and…

8. View, fuel waste tanks and containment basin associated with ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. View, fuel waste tanks and containment basin associated with Components Test Laboratory (T-27) located uphill to the left, looking northwest. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Monitoring and analysis of frozen debris lobes using remote sensing : final report.

DOT National Transportation Integrated Search

2016-01-01

Frozen debris lobes (FDLs) are slow-moving landslides within permafrost on slopes located in : the Brooks Range of Alaska. Forty-three FDLs are located within the Dalton Highway corridor, : with 23 occurring less than one mile uphill of the Dalton Hi...

Laboratory versus outdoor cycling conditions: differences in pedaling biomechanics.

PubMed

Bertucci, William; Grappe, Frederic; Groslambert, Alain

2007-05-01

The aim of our study was to compare crank torque profile and perceived exertion between the Monark ergometer (818 E) and two outdoor cycling conditions: level ground and uphill road cycling. Seven male cyclists performed seven tests in seated position at different pedaling cadences: (a) in the laboratory at 60, 80, and 100 rpm; (b) on level terrain at 80 and 100 rpm; and (c) on uphill terrain (9.25% grade) at 60 and 80 rpm. The cyclists exercised for 1 min at their maximal aerobic power. The Monark ergometer and the bicycle were equipped with the SRM Training System (Schoberer, Germany) for the measurement of power output (W), torque (Nxm), pedaling cadence (rpm), and cycling velocity (kmxh-1). The most important findings of this study indicate that at maximal aerobic power the crank torque profiles in the Monark ergometer (818 E) were significantly different (especially on dead points of the crank cycle) and generate a higher perceived exertion compared with road cycling conditions.

Mechanical Design and Testing of an Instrumented Rocker-Bogie Mobility System for the Kapvik Micro-Rover

NASA Astrophysics Data System (ADS)

Setterfield, T.

The rocker-bogie mobility system is a six-wheeled mobility system with the ability to equilibrate ground pressure amongst its wheels and traverse obstacles up to one wheel diameter in height; it has been used previously on NASA's Sojourner, Spirit, Opportunity and Curiosity rovers. This paper presents the mechanical design of an instrumented rocker-bogie mobility system for Kapvik, a 30 kg planetary micro-rover prototype developed for the Canadian Space Agency. The design of the wheel drive system is presented, including: motor selection, gear train selection, and performance limits. The design of a differential mechanism, which minimizes the pitch angle of the rover body, is provided. Design considerations for the integration of single-axis force sensors above the wheel hubs are presented. Structural analysis of the rocker and bogie links is outlined. The cross-hill and uphill-downhill static stability of Kapvik is investigated. Load cell and joint position data from testing during obstacle negotiation and uphill operation are presented.

Method comparisons of vehicle emissions measurements in the fort mchenry and Tuscarora mountain tunnels

NASA Astrophysics Data System (ADS)

Bishop, Gary A.; McLaren, Scott E.; Stedman, Donald H.; Pierson, William R.; Zweidinger, Roy B.; Ray, William D.

Experiments were conducted in the Fort McHenry Tunnel in Baltimore, MD, and in the Tuscarora Mountain Tunnel in Pennsylvania, during the summer of 1992 to evaluate real-world automotive emissions. Included in these experiments were the first reported measurements of individual vehicle exhaust in tunnels by a remote sensing device (RSD). Results are compared to integrated emission measurements carried out by analysis of concurrent collections of tunnel air into bags, canisters, and adsorbent traps and by conventional Fourier transform infrared (FTIR) spectroscopy. The vehicles using these highway tunnels proved to be lower emitting than vehicles usually measured by remote sensing in urban areas. At Fort McHenry the RSD-measured CO/CO2 ratios were, on average, high compared to either the bag or FTIR measurements (by a factor of 1.4 ± 0.2) for the four runs monitored. RSD hydrocarbon data were obtained only at the uphill location ( + 3.76% grade). RSD HC/CO2 ratios were lower on average, but statistically indistinguishable when compared with either the FTIR or the integrated uphill measurements. At Tuscarora, the RSD-measured CO/CO2 ratios were in agreement with the CO/CO2 ratios in the tunnel bag measurements and FTIR measurements (within a factor of 1.00 ± 0.16 by one method and 0.82 ± 0.32 by a second, when traffic was dominated by light-duty spark-ignition vehicles). The RSD HC/CO2 ratios were, however, higher than the light-duty vehicle estimates from the integrated (bag/canister/Tenax) tunnel measurements by a factor of 3, and higher than the FTIR Δ HC/Δ CO2 ratios by an even higher factor, mostly owing to water vapor interferences in the low average RSD measurements. For the first time RSD measurements were collected from a small sample of heavy-duty diesels; comparisons to the heavy-duty emissions contributions for CO and HC were favorable. Analysis of emissions data for vehicle variability at Fort McHenry revealed that low CO emitting vehicles tended to be consistently low but that the minority that were high emitters ( > 2.5% CO) were more likely to be high only at the uphill location. Vehicle mileage information was collected at a toll booth in the case of Fort McHenry and at a service plaza in the case of Tuscarora for comparison against the RSD emissions measurements. This comparison showed little conventional deterioration of CO or HC emissions with mileage. The trend consisted of an increased frequency of high emitters with mileage, rather than an increase in emissions from all vehicles with increasing mileage.

Enhanced Droplet Control by Transition Boiling

PubMed Central

Grounds, Alex; Still, Richard; Takashina, Kei

2012-01-01

A droplet of water on a heated surface can levitate over a film of gas produced by its own evaporation in the Leidenfrost effect. When the surface is prepared with ratchet-like saw-teeth topography, these droplets can self-propel and can even climb uphill. However, the extent to which the droplets can be controlled is limited by the physics of the Leidenfrost effect. Here, we show that transition boiling can be induced even at very high surface temperatures and provide additional control over the droplets. Ratchets with acute protrusions enable droplets to climb steeper inclines while ratchets with sub-structures enable their direction of motion to be controlled by varying the temperature of the surface. The droplets' departure from the Leidenfrost regime is assessed by analysing the sound produced by their boiling. We anticipate these techniques will enable the development of more sophisticated methods for controlling small droplets and heat transfer. PMID:23056912

Enhanced Droplet Control by Transition Boiling

NASA Astrophysics Data System (ADS)

Grounds, Alex; Still, Richard; Takashina, Kei

2012-10-01

A droplet of water on a heated surface can levitate over a film of gas produced by its own evaporation in the Leidenfrost effect. When the surface is prepared with ratchet-like saw-teeth topography, these droplets can self-propel and can even climb uphill. However, the extent to which the droplets can be controlled is limited by the physics of the Leidenfrost effect. Here, we show that transition boiling can be induced even at very high surface temperatures and provide additional control over the droplets. Ratchets with acute protrusions enable droplets to climb steeper inclines while ratchets with sub-structures enable their direction of motion to be controlled by varying the temperature of the surface. The droplets' departure from the Leidenfrost regime is assessed by analysing the sound produced by their boiling. We anticipate these techniques will enable the development of more sophisticated methods for controlling small droplets and heat transfer.

sedFlow - a tool for simulating fractional bedload transport and longitudinal profile evolution in mountain streams

NASA Astrophysics Data System (ADS)

Heimann, F. U. M.; Rickenmann, D.; Turowski, J. M.; Kirchner, J. W.

2015-01-01

Especially in mountainous environments, the prediction of sediment dynamics is important for managing natural hazards, assessing in-stream habitats and understanding geomorphic evolution. We present the new modelling tool {sedFlow} for simulating fractional bedload transport dynamics in mountain streams. sedFlow is a one-dimensional model that aims to realistically reproduce the total transport volumes and overall morphodynamic changes resulting from sediment transport events such as major floods. The model is intended for temporal scales from the individual event (several hours to few days) up to longer-term evolution of stream channels (several years). The envisaged spatial scale covers complete catchments at a spatial discretisation of several tens of metres to a few hundreds of metres. sedFlow can deal with the effects of streambeds that slope uphill in a downstream direction and uses recently proposed and tested approaches for quantifying macro-roughness effects in steep channels. sedFlow offers different options for bedload transport equations, flow-resistance relationships and other elements which can be selected to fit the current application in a particular catchment. Local grain-size distributions are dynamically adjusted according to the transport dynamics of each grain-size fraction. sedFlow features fast calculations and straightforward pre- and postprocessing of simulation data. The high simulation speed allows for simulations of several years, which can be used, e.g., to assess the long-term impact of river engineering works or climate change effects. In combination with the straightforward pre- and postprocessing, the fast calculations facilitate efficient workflows for the simulation of individual flood events, because the modeller gets the immediate results as direct feedback to the selected parameter inputs. The model is provided together with its complete source code free of charge under the terms of the GNU General Public License (GPL) (www.wsl.ch/sedFlow). Examples of the application of sedFlow are given in a companion article by Heimann et al. (2015).

A Service-Learning Exercise in Building Civil Engagement in Teacher Education

ERIC Educational Resources Information Center

Moguel, David L.

2003-01-01

Service learning can be a vehicle to promote democracy in the teacher education classroom. Incorporating service learning into a teacher education program is an uphill battle: teacher candidates lead complicated lives with professional and family responsibilities, some continue long-standing volunteer commitments to their communities, and course…

The New Zealand-Born Chinese Community of Auckland: Aspects of Language Maintenance and Shift.

ERIC Educational Resources Information Center

Sun, Susan

1999-01-01

Examines the Chinese immigrant community in Auckland, New Zealand and how they address the question of first language maintenance in their largely new English-speaking environment. Shows that language maintenance, especially the written language is going to be an uphill struggle. (Author/VWL)

Be Active Your Way: A Guide for Adults

MedlinePlus

... try): ❑ Aerobic dance ❑ Basketball ❑ Fast dancing ❑ Jumping rope ❑ Martial arts (such as karate) ❑ Race walking, jogging, or running ❑ ... Heavy gardening (digging,hoeing) • Hiking uphill • Jumping rope • Martial arts (such as karate) • Race walking,jogging,or running • ...

Rolling Uphill

ERIC Educational Resources Information Center

Cross, Rod

2017-01-01

In a recent letter to this journal, Mungan noted that translational energy can be converted into gravitational potential energy when an object is projected vertically, but rotational energy is not usually converted in this manner. As an exception, he gave an example where "a ball initially rolling without slipping will travel higher up a…

A Full Plate for Schools.

ERIC Educational Resources Information Center

Marlowe, John

2002-01-01

As of summer 2001, at least 12 states are deep-sixing junk foods in schools. Schools face an uphill battle on nutrition education. Commercials promoting junk food seem ubiquitous, and children are spending too many inactive hours watching television. Major challenges include the open-campus lunch period and cash-strapped schools using profits from…

Changes in ground beetle assemblages above and below the treeline of the Dolomites after almost 30 years (1980/2009)

PubMed Central

Pizzolotto, Roberto; Gobbi, Mauro; Brandmayr, Pietro

2014-01-01

Very little is known about the changes of ground beetle assemblages in the last few decades in the Alps, and different responses to climate change of animal populations living above and below the treeline have not been estimated yet. This study focuses on an altitudinal habitat sequence from subalpine spruce forest to alpine grassland in a low disturbance area of the southeastern Dolomites in Italy, the Paneveggio Regional Park. We compared the ground beetle (Carabidae) populations sampled in 1980 in six stands below and above the treeline (1650–2250 m a.s.l.) with those sampled in the same sites almost 30 years later (2008/9). Quantitative data (species richness and abundance) have been compared by means of several diversity indexes and with a new index, the Index of Rank-abundance Change (IRC). Our work shows that species richness and abundance have changed after almost 30 years as a consequence of local extinctions, uphill increment of abundance and uphill shift of distribution range. The overall species number dropped from 36 to 27, while in the sites above the treeline, species richness and abundance changed more than in the forest sites. Two microtherm characteristic species of the pioneer cushion grass mats, Nebria germari and Trechus dolomitanus, became extinct or showed strong abundance reduction. In Nardetum pastures, several hygrophilic species disappeared, and xerophilic zoophytophagous elements raised their population density. In forest ecosystems, the precipitation reduction caused deep soil texture and watering changes, driving a transformation from Sphagnum-rich (peaty) to humus-rich soil, and as a consequence, soil invertebrate biomass strongly increased and thermophilic carabids enriched the species structure. In three decades, Carabid assemblages changed consistently with the hypothesis that climate change is one of the main factors triggering natural environment modifications. Furthermore, the level of human disturbance could enhance the sensitivity of mountain ecosystems to climate change. PMID:24834326

Changes in ground beetle assemblages above and below the treeline of the Dolomites after almost 30 years (1980/2009).

PubMed

Pizzolotto, Roberto; Gobbi, Mauro; Brandmayr, Pietro

2014-04-01

Very little is known about the changes of ground beetle assemblages in the last few decades in the Alps, and different responses to climate change of animal populations living above and below the treeline have not been estimated yet. This study focuses on an altitudinal habitat sequence from subalpine spruce forest to alpine grassland in a low disturbance area of the southeastern Dolomites in Italy, the Paneveggio Regional Park. We compared the ground beetle (Carabidae) populations sampled in 1980 in six stands below and above the treeline (1650-2250 m a.s.l.) with those sampled in the same sites almost 30 years later (2008/9). Quantitative data (species richness and abundance) have been compared by means of several diversity indexes and with a new index, the Index of Rank-abundance Change (IRC). Our work shows that species richness and abundance have changed after almost 30 years as a consequence of local extinctions, uphill increment of abundance and uphill shift of distribution range. The overall species number dropped from 36 to 27, while in the sites above the treeline, species richness and abundance changed more than in the forest sites. Two microtherm characteristic species of the pioneer cushion grass mats, Nebria germari and Trechus dolomitanus, became extinct or showed strong abundance reduction. In Nardetum pastures, several hygrophilic species disappeared, and xerophilic zoophytophagous elements raised their population density. In forest ecosystems, the precipitation reduction caused deep soil texture and watering changes, driving a transformation from Sphagnum-rich (peaty) to humus-rich soil, and as a consequence, soil invertebrate biomass strongly increased and thermophilic carabids enriched the species structure. In three decades, Carabid assemblages changed consistently with the hypothesis that climate change is one of the main factors triggering natural environment modifications. Furthermore, the level of human disturbance could enhance the sensitivity of mountain ecosystems to climate change.

Environmental controls on sap flow in black locust forest in Loess Plateau, China.

PubMed

Ma, Changkun; Luo, Yi; Shao, Mingan; Li, Xiangdong; Sun, Lin; Jia, Xiaoxu

2017-10-13

Black locust accounts for over 90% of artificial forests in China's Loess Plateau region. However, water use of black locust is an uphill challenge for this semi-arid region. To accurately quantify tree water use and to explain the related hydrological processes, it is important to collect reliable data for application in the estimation of sap flow and its response to environmental factors. This study measured sap flow in black locust in the 2015 and 2016 growth seasons using the thermal dissipation probes technique and laboratory-calibrated Granier's equation. The study showed that the laboratory calibrated coefficient α was much larger than the original value presented by Granier, while the coefficient β was similar to the original one. The average daily transpiration was 2.1 mm day -1 for 2015 and 1.6 mm day -1 for 2016. Net solar radiation (Rn) was the key meteorological factor controlling sap flow, followed by vapor pressure deficit (VPD) and then temperature (T). VPD had a threshold control on sap flow at threshold values of 1.9 kPa for 2015 and 1.6 kPa for 2016. The effects of diurnal hysteresis of Rn, VPD and T on sap flow were evident, indicating that black locust water use was conservative.

Family Science and Community-Based Learning: Using Speed Networking

ERIC Educational Resources Information Center

Payne, Pamela B.; Hubler, Daniel S.

2017-01-01

Students in Family Science often feel that they have an uphill battle to finding career opportunities that maximize their experiences from degree programs. The hallmark of successful programs in Family Science needs to be the development and maintenance of high-quality field experiences for students that align with national standards and…

Survey Shows Blacks Not Concerned Enough about Kidney Disease

ERIC Educational Resources Information Center

Black Issues in Higher Education, 2004

2004-01-01

Health officials may have an uphill battle in educating Blacks about a disease that's being called a "silent killer," a recent survey shows. Kidney disease is an illness that's become more prevalent, especially in the nation's Black population, but a survey conducted in Jackson, Atlanta, Baltimore and Cleveland shows only 15 percent of those…

No Such Word as "Can't": The Uphill Struggle of the Black Classical Singer.

ERIC Educational Resources Information Center

Verdino-Sullwold, Carla Maria

1991-01-01

Although the difficulties encountered during the first half of the twentieth century by such singers as Paul Robeson, Marian Anderson, and Roland Hayes are history, the recent struggles of black classical singers for recognition illustrate current barriers. Several prominent black opera and concert artists recount their experiences. (SLD)

Self-Help and Community Education. Courier No. 28.

ERIC Educational Resources Information Center

ASPBAE Courier, 1983

1983-01-01

This journal consists of eight articles dealing with self-help and community education. Included in the volume are the following articles: "An Uphill Struggle--Self-Help in Bangladesh," by S. Harrison and Judy Saul; "How Not to Help a Local Community: A Case from South India," by Nora Sammut and Maria Theresa; "The High…

Perspectives / The Uphill Climb

ERIC Educational Resources Information Center

Scherer, Marge

2013-01-01

The video "Wealth Inequality in America" sets forth a compelling animated chart depicting three ideas: (1) how Americans think wealth is distributed in the United States;(2) how they believe wealth ideally should be distributed; and (3) how the estimated $54 trillion of U.S. wealth is really divided. The hard-to-miss conclusion of the…

Guidelines and Advice for Successful Publication Provided by Journal Editors

ERIC Educational Resources Information Center

Miller, Luke T.; Smith, Alice; Labach, Elaine

2010-01-01

Journal publication is an important indicator of research productivity for individual researchers, as well as academic institutions. However, for novice faculty members, the publication process can appear equivocal and daunting. If the academic does not actively engage themselves early in this process, then her or his career becomes an uphill (and…

Cerro Xalapaxco: An Unusual Tuff Cone with Multiple Explosion Craters, in Central Mexico (Puebla)

NASA Technical Reports Server (NTRS)

Abrams, M. J.; Siebe, C.

1994-01-01

The Xalapaxco tuff cone is located on the northeast flank of La Malinche stratovolcano in central Mexico. An unusually large number (10) of explosion craters, concentrated on the central and on the uphill side of the cone, expose alternating beds of stratified surge deposits and massive fall deposits.

Old Habits Die Hard: An Uphill Struggle against Rules without Reason in Mathematics Teacher Education

ERIC Educational Resources Information Center

O'Meara, Niamh; Fitzmaurice, Olivia; Johnson, Patrick

2017-01-01

Mathematics teacher educators in the University of Limerick became aware of a lack of conceptual understanding of key mathematics concepts of prospective secondary mathematics teachers through observation on teaching placement and in pedagogy lectures. A pilot study to enhance the conceptual understanding of prospective teachers was carried out…

The Teaching Penalty: An Update through 2010. EPI Issue Brief #298

ERIC Educational Resources Information Center

Allegretto, Sylvia A.; Corcoran, Sean P.; Mishel, Lawrence

2011-01-01

Effective teachers are demonstrably the most important resource schools have for improving the academic success of their students. Yet for many school leaders, recruiting and retaining talented and effective classroom teachers remains an uphill battle. Whether teacher salaries are sufficient to attract the best graduates into teaching remains an…

Developing a Stakeholder Approach for Recruiting Top-Level Sales Students

ERIC Educational Resources Information Center

Agnihotri, Raj; Bonney, Leff; Dixon, Andrea Leigh; Erffmeyer, Robert; Pullins, Ellen Bolman; Sojka, Jane Z.; West, Vicki

2014-01-01

With growing industry demand for sales professionals, recruitment at colleges and universities that have a sales education focus has increased remarkably over the past few years. However, results indicate that hiring organizations face an uphill task in filling sales positions. Recruiters and students struggle to build critical person-job fit…

Quality in Higher Education: United Arab Emirates Perspective

ERIC Educational Resources Information Center

Soomro, Tariq Rahim; Ahmad, Reyaz

2012-01-01

Quality in higher education is the major concern among researchers. Managing quality in higher education in a multicultural population with different approaches is not only challenging but an uphill task. This paper will focus on quality concern in higher education keeping in view, the United Arab Emirates (UAE) perspectives. A model to maintain…

Do Maximal Roller Skiing Speed and Double Poling Performance Predict Youth Cross-Country Skiing Performance?

PubMed Central

Stöggl, Roland; Müller, Erich; Stöggl, Thomas

2017-01-01

The aims of the current study were to analyze whether specific roller skiing tests and cycle length are determinants of youth cross-country (XC) skiing performance, and to evaluate sex specific differences by applying non-invasive diagnostics. Forty-nine young XC skiers (33 boys; 13.8 ± 0.6 yrs and 16 girls; 13.4 ± 0.9 yrs) performed roller skiing tests consisting of both shorter (50 m) and longer durations (575 m). Test results were correlated with on snow XC skiing performance (PXC) based on 3 skating and 3 classical distance competitions (3 to 6 km). The main findings of the current study were: 1) Anthropometrics and maturity status were related to boys’, but not to girls’ PXC; 2) Significant moderate to acceptable correlations between girls’ and boys’ short duration maximal roller skiing speed (double poling, V2 skating, leg skating) and PXC were found; 3) Boys’ PXC was best predicted by double poling test performance on flat and uphill, while girls’ performance was mainly predicted by uphill double poling test performance; 4) When controlling for maturity offset, boys’ PXC was still highly associated with the roller skiing tests. The use of simple non-invasive roller skiing tests for determination of PXC represents practicable support for ski clubs, schools or skiing federations in the guidance and evaluation of young talent. Key points Double poling tests on flat and uphill terrain and short duration maximal speed tests were the highest cross-country skiing predicting factors in girls and boys. Only in the boys there was an effect of maturation on the performance outcomes, pointing out that girls seem to be almost fully matured at the age of 13 in contrast to the boys. Roller skiing tests over short distance (50-m) and longer distance 225 m and 350 m are stable and valid measures and suitable for performance prediction in youth cross-country skiers. PMID:28912656

Treadmill training with an incline reduces ankle joint stiffness and improves active range of movement during gait in adults with cerebral palsy.

PubMed

Lorentzen, Jakob; Kirk, Henrik; Fernandez-Lago, Helena; Frisk, Rasmus; Scharff Nielsen, Nanna; Jorsal, Martin; Nielsen, Jens Bo

2017-05-01

We investigated if 30 min of daily treadmill training with an incline for 6 weeks would reduce ankle joint stiffness and improve active range of movement in adults with cerebral palsy (CP). The study was designed as a randomized controlled clinical trial including 32 adults with CP (GMFCS 1-3) aged 38.1 SD 12 years. The training group (n = 16) performed uphill treadmill training at home daily for 30 min for 6 weeks in addition to their usual activities. Passive and reflex mediated stiffness and range of motion (ROM) of the ankle joint, kinematic and functional measures of gait were obtained before and after the intervention/control period. Intervention subjects trained 31.4 SD 10.1 days for 29.0 SD 2.3 min (total) 15.2 h. Passive ankle joint stiffness was reduced (F = 5.1; p = 0.031), maximal gait speed increased (F = 42.8, p < 0.001), amplitude of toe lift prior to heel strike increased (F = 5.3, p < 0.03) and ankle angle at heel strike was decreased (F = 12.5; p < 0.001) significant in the training group as compared to controls. Daily treadmill training with an incline for 6 weeks reduces ankle joint stiffness and increases active ROM during gait in adults with CP. Intensive gait training may thus be beneficial in preventing and reducing contractures and help to maintain functional gait ability in adults with CP. Implications for rehabilitation Uphill gait training is an effective way to reduce ankle joint stiffness in adult with contractures. 6 weeks of daily uphill gait training improves functional gait parameters such as gait speed and dorsal flexion during gait in adults with cerebral palsy.

Multisegment Foot Kinematic and Kinetic Compensations in Level and Uphill Walking Following Tibiotalar Arthrodesis.

PubMed

Bruening, Dustin A; Cooney, Timothy E; Ray, Matthew S; Daut, Gregory A; Cooney, Kevin M; Galey, Stephanie M

2016-10-01

Foot and ankle movement alterations following ankle arthrodesis are still not well understood, particularly those that might contribute to the documented increase in adjacent joint arthritis. Generalized tarsal hypermobility has long been postulated, but not confirmed in gait or functional movements. The purpose of this study was to more thoroughly evaluate compensation mechanisms used by arthrodesis patients during level and uphill gait through a variety of measurement modalities and a detailed breakdown of gait phases. Level ground and uphill gait of 14 unilateral tibiotalar arthrodesis patients and 14 matched controls was analyzed using motion capture, force, and pressure measurements in conjunction with a kinetic multisegment foot model. The affected limb exhibited several marked differences compared to the controls and to the unaffected limb. In loading response, ankle eversion was reduced but without a reduction in tibial rotation. During the second rocker, ankle dorsiflexion was reduced, yet was still considerable, suggesting compensatory talar articulation (subtalar and talonavicular) motion since no differences were seen at the midtarsal joint. Also during the second rocker, subjects abnormally internally rotated the tibia while moving their center of pressure laterally. Third rocker plantarflexion motion, moments, and powers were substantially reduced on the affected side and to a lesser extent on the unaffected side. Sagittal plane hypermobility is probable during the second rocker in the talar articulations following tibiotalar fusion, but is unlikely in other midfoot joints. The normal coupling between frontal plane hindfoot motion and tibial rotation in early and mid stance was also clearly disrupted. These alterations reflect a complex compensatory movement pattern that undoubtedly affects the function of arthrodesis patients, likely alters the arthrokinematics of the talar joints (which may be a mechanism for arthritis development), and should be considered in future arthrodesis as well as arthroplasty research. Level III, comparative study. © The Author(s) 2016.

Ice in Channels and Ice-Rock Mixtures in Valleys on Mars: Did They Slide on Deformable Rubble Like Antarctic Ice Streams?

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1997-01-01

Recent studies of ice streams in Antarctica reveal a mechanism of basal motion that may apply to channels and valleys on Mars. The mechanism is sliding of the ice on deformable water-saturated till under high pore pressures. It has been suggested by Lucchitta that ice was present in outflow channels on Mars and gave them their distinctive morphology. This ice may have slid like Antarctic ice streams but on rubbly weathering products rather than till. However, to generate water under high pore pressures, elevated heatflow is needed to melt the base of the ice. Either volcanism or higher heatflow more than 2 b.y. ago could have raised the basal temperature. Regarding valley networks, higher heatflow 3 b.y. ago could have allowed sliding of ice-saturated overburden at a few hundred meters depth. If the original, pristine valleys were somewhat deeper than they are now, they could have formed by the same mechanism. Recent sounding of the seafloor in front of the Ross Ice Shelf in Antarctica reveals large persistent patterns of longitudinal megaflutes and drumlinoid forms, which bear remarkable resemblance to longitudinal grooves and highly elongated streamlined islands found on the floors of martian outflow channels. The flutes are interpreted to have formed at the base of ice streams during the last glacial advance. Additional similarities of Antarctic ice streams with martian outflow channels are apparent. Antarctic ice streams are 30 to 80 km wide and hundreds of kilometers long. Martian outflow channels have similar dimensions. Ice stream beds are below sea level. Carr determined that most common floor elevations of martian outflow channels lie below martian datum, which may have been close to or below past martian sea levels. The Antarctic ice stream bed gradient is flat and locally may go uphill, and surface slopes are exceptionally. Martian channels also have floor gradients that are shallow or go uphill locally and have low surface gradients. The depth to the bed in ice streams is 1 to 1.5 km. At bankful stage, the depth of the fluid in outflow channels was 1 to 2 km, according to the height of bordering scarps. The similarity between Antarctic ice streams and martian outflow channels suggests that ice may have flowed through and shaped the outflow channels, and that perhaps the mechanism of motion of Antarctic ice streams also operated in outflow channels. In addition, sliding on deformable rubble may explain the formation of small valley networks. The large Siple Coast Antarctic ice streams are thought to slide over longitudinally grooved, deforming till, where much of the movement is within the till. The till is saturated with water at high pore pressures that nearly supports all of the weight of the ice. The small differential between overburden pressure and pore pressure at the bed is more important than the volume of water, but water needs to be supplied to the till interface. For pore pressures to remain high, the ice streams have to act as a seal that blocks the flow of water through them, and the rock underneath has to be of low permeability to prevent the water from draining away.

The Western North Carolina Technology Consortium: A Collaborative Approach to Bridging the Digital Divide

ERIC Educational Resources Information Center

Sink, David W.; Jackson, Karen Luke; Boham, Kenneth A.; Shockley, David

2004-01-01

Community college presidents face an uphill struggle in preparing their institutions for the rapidly changing technological learning environment. Visionary presidents in rural community colleges are presented with yet another challenge: that of finding themselves on the wrong side of the digital divide. This article describes how presidents of 12…

"Find the Strength in Every Teacher": Urban Middle School Teachers' Perceptions of Effective Change Leadership

ERIC Educational Resources Information Center

Allen, Timothy Clancy

2013-01-01

Urban middle schools face many accountability measures which often create the need for school improvement. Leading urban middle schools through the change process is extremely challenging for principals. The combination of leading change, leading urban schools, and leading middle schools is an uphill climb. Teachers' perceptions of leadership…

Letting the Cat out of the Bag: EFL College Students' Attitudes towards Learning English Idioms

ERIC Educational Resources Information Center

Al-Houti, Shorouq K.; Aldaihani, Sultan M.

2018-01-01

Learning idioms is an uphill battle for many language learners. Thus, this quantitative study aims to shed light on English as Foreign Language (EFL) college students' attitudes towards idiom learning. Specifically, the study is interested in revealing their attitudes towards (1) the importance of idiom learning, (2) the difficulties of idiom…

Operational test of the prototype peewee yarder.

Treesearch

Charles N. Mann; Ronald W. Mifflin

1979-01-01

An operational test of a small, prototype running skyline yarder was conducted early in 1978. Test results indicate that this yarder concept promises a low cost, high performance system for harvesting small logs where skyline methods are indicated. Timber harvest by thinning took place on 12 uphill and 2 downhill skyline roads, and clearcut harvesting was performed on...

Is Retaining Students in the Early Grades Self-Defeating? CCF Brief #49

ERIC Educational Resources Information Center

West, Martin R.

2012-01-01

Whether a child is a proficient reader by the third grade is an important indicator of their future academic success. Indeed, substantial evidence indicates that unless students establish basic reading skills by that time, the rest of their education will be an uphill struggle. This evidence has spurred efforts to ensure that all students receive…

CTE Funding: An Uphill Battle

ERIC Educational Resources Information Center

Baxter, Jamie

2012-01-01

For the last decade, career and technical education (CTE) funding has seen some ups, but mostly downs. While it received a modest increase in 2002, that increase was swept away in 2008 due to across-the-board cuts. It was difficult for CTE to receive another increase in the early 2000s because every year the Bush Administration proposed to either…

Change Forces: Probing the Depths of Educational Reform. School Development and the Management of Change Series: 10.

ERIC Educational Resources Information Center

Fullan, Michael

Debunking popular reform efforts, this book argues that education reformers are fighting a fruitless uphill battle. Neither top-down regulation nor locally based reforms will transform schooling. The insurmountable problem is juxtaposing a continuous change theme with a continuous, conservative system that defies change. In partnership with all…

Trunk and root sprouting on residual trees after thinning a Quercus chrysolepis stand

Treesearch

Timothy E. Paysen; Marcia G. Narog; Robert G. Tissell; Melody A. Lardner

1991-01-01

Canyon live oak (Quercus chrysolepis Liebm.) showed sprouting patterns on root and trunk zones foUowing forest thinning. Root sprouting was heaviest on north and east (downhill) sides of residual trees; bole sprouts were concentrated on the south and west (uphill). Root and bole sprouting appeared to be responding to different stimuli, or...

The Pursuit of Gender Equality: An Uphill Battle

ERIC Educational Resources Information Center

OECD Publishing, 2017

2017-01-01

Gender inequalities persist in all areas of social and economic life and across countries. Young women in OECD countries generally obtain more years of schooling than young men, but women are less likely than men to engage in paid work. Gaps widen with age, as motherhood typically has marked negative effects on gender pay gaps and career…

Keeping an Uphill Edge: Managing Cleaning Behaviors at a Ski Shop

ERIC Educational Resources Information Center

Doll, Jessica; Livesey, Josh; McHaffie, Elizabeth; Ludwig, Timothy D.

2007-01-01

Several behaviors in a ski shop were identified as being deficient using Austin's Performance Diagnostic Checklist (2000) and Daniels and Daniels' PIC/NIC Analysis (2004). During a 4-week baseline, 7 cleaning behaviors were monitored and 5 were subsequently targeted in an intervention package using an ABC design. The intervention included: a task…

Running uphill: urbanization, conflict, and visitor use at Kennesaw Mountain National Battlefield Park

Treesearch

Julie A. Strack; Craig A. Miller

2008-01-01

At the Kennesaw Mountain National Battlefield, operated by the National Park Service (NPS) near Atlanta, differing uses--including walking for fitness, horseback riding, and organized crosscountry running team practices on the trails--conflict with the NPS mission to protect the historic resources of the site and lead to conflicts among visitors. NPS managers at...

Nurse Refresher Students Get a Hand from Handhelds

ERIC Educational Resources Information Center

Colevins, Helen; Bond, Diana; Clark, Kathy

2006-01-01

Returning registered nurses face an uphill challenge when re-entering their field. To help ease the technology shock for nurses who have been out of the field for more than 5 years, info pros in one medical library collaborated with administrators of a nursing education program to purchase Personal Digital Assistants (PDAs) and load them with…

The Bicyclist's Paradox

ERIC Educational Resources Information Center

Knight, Randy

2008-01-01

It's a situation every avid cyclist knows only too well. If you cycle up a hill and then back down with no net change in elevation, it seems as if your slower uphill speed and faster downhill speed should offset each other. But they don't. Your average speed is less than it would have been had you cycled the same distance on a level road.…

Cost and production analysis of the Bitterroot Miniyarder on an Appalachian hardwood site

Treesearch

John E. Baumgras; Penn A. Peters; Penn A. Peters

1985-01-01

An 18-horsepower skyline yarder was studied on a steep slope clearcut, yarding small hardwood trees uphill for fuelwood. Yarding cycle characteristics sampled include: total cycle time including delays, 5.20 minutes; yarding distance, 208 feet (350 feet maximum); turn volume, 11.6 cubic feet (24 cubic feet maximum); pieces per turn, 2.3. Cost analysis shows yarding...

Simple Models to Explore Deterrence and More General Influence in the War with al-Qaeda

DTIC Science & Technology

2010-01-01

Academy of Sciences, 1996).9 Regrettably, few of these enrichments come to most people’s minds when the term “deter- rence” is used. Instead, they...may flour - ish. Efforts to reduce the root-cause factors using “influence” will, in most cases, be uphill and long-term in nature. Moreover, it is

Building Schools in a Tight Economy? Do Your Homework

ERIC Educational Resources Information Center

Watts, Chris

2009-01-01

With unemployment rising and the public more concerned about the economy than at any other time in recent memory, the idea of a municipality deciding to spend millions of dollars to build or refurbish a school seems an uphill challenge to say the least. In the best of times, voter approval for school construction projects is difficult to get;…

Staying on Course: Three-Year Results of the National Guard Youth ChalleNGe Evaluation. Executive Summary

ERIC Educational Resources Information Center

Millenky, Megan; Bloom, Dan; Muller-Ravett, Sara; Broadus, Joseph

2011-01-01

High school dropouts face an uphill battle in a labor market that increasingly rewards skills and postsecondary credentials: they are more likely than their peers to need public assistance, be arrested or incarcerated, and less likely to marry. This executive summary summarizes results from a rigorous evaluation of the National Guard Youth…

4. View, fuel waste tanks and containment basin in foreground ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. View, fuel waste tanks and containment basin in foreground with Systems Integration Laboratory (T-28) uphill in background, looking southeast. At the extreme right is the Long-Term Oxidizer Silo (T-28B) and the Oxidizer Conditioning Structure (T-28D). - Air Force Plant PJKS, Systems Integration Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

6. View, flare and oxygen burner pad near southwest side ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. View, flare and oxygen burner pad near southwest side of Components Test Laboratory (T-27), looking northeast. Uphill and to the left of the flare is the Oxidizer Conditioning Structure (T-28D) and the Long-Term Oxidizer Silo (T-28B). - Air Force Plant PJKS, Systems Integration Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Preserving the Promise of Higher Education in an Era of Fiscal Challenges

ERIC Educational Resources Information Center

Academe, 2005

2005-01-01

As several articles in the July-August 2004 issue of Academe discuss, recent patterns in state funding have hurt higher education. Although there are some signs that state budgets are beginning to recover from "the worst fiscal crisis in the last sixty years," officials still expect "an uphill battle," according to the Fiscal Survey of the States…

Academic and Social Integration: A Phenomenological Study of First-Generation, Female Student Experience and Persistence in Community College TRiO Programs

ERIC Educational Resources Information Center

Parsons, Brianna Bates

2012-01-01

First-generation, female college students often face an uphill battle in their quest for degree attainment. Literature suggests several areas in which first-generation college students struggle, but there are programs designed to help this demographic of student; specifically the TRiO program, a federally-funded operation that specializes in…

Up, down, and across the Land: Landscape Terms, Place Names, and Spatial Language in Tzeltal

ERIC Educational Resources Information Center

Brown, Penelope

2008-01-01

The Tzeltal language is spoken in a mountainous region of southern Mexico by some 280,000 Mayan corn farmers. This paper focuses on landscape and place vocabulary in the Tzeltal municipio of Tenejapa, where speakers use an absolute system of spatial reckoning based on the overall uphill (southward)/downhill (northward) slope of the land. The paper…

8. SECOND IMAGE OF THE PANORAMIC SERIES LOOKING WEST FROM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. SECOND IMAGE OF THE PANORAMIC SERIES LOOKING WEST FROM THE UPHILL SIDE OF THE MILL. THE ORE RECEIVING HOUSE AND THE ORE DELIVERY TRESTLE IS IMAGE RIGHT, THE MILL BUILDING AND ANCILLARY STRUCTURE ARE IMAGE CENTER AND THE TOWN OF BODIE IS IMAGE BACKGROUND RIGHT. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

Beyond Socioeconomic Status: The Impact of Principal Leadership in Urban and High-Poverty Turnaround Schools

ERIC Educational Resources Information Center

Adejumo, Mojisola

2017-01-01

The quest to transform failing urban and high-poverty schools in America has been a slippery uphill battle since the banner of war was raised against the many schools serving impoverished children. As battle rages, a few are schools leading their students, teachers, parents, and community to victory by turning their once-failing schools into…

Up by upwest: Is slope like north?

PubMed

Weisberg, Steven M; Nardi, Daniele; Newcombe, Nora S; Shipley, Thomas F

2014-10-01

Terrain slope can be used to encode the location of a goal. However, this directional information may be encoded using a conceptual north (i.e., invariantly with respect to the environment), or in an observer-relative fashion (i.e., varying depending on the direction one faces when learning the goal). This study examines which representation is used, whether the sensory modality in which slope is encoded (visual, kinaesthetic, or both) influences representations, and whether use of slope varies for men and women. In a square room, with a sloped floor explicitly pointed out as the only useful cue, participants encoded the corner in which a goal was hidden. Without direct sensory access to slope cues, participants used a dial to point to the goal. For each trial, the goal was hidden uphill or downhill, and the participants were informed whether they faced uphill or downhill when pointing. In support of observer-relative representations, participants pointed more accurately and quickly when facing concordantly with the hiding position. There was no effect of sensory modality, providing support for functional equivalence. Sex did not interact with the findings on modality or reference frame, but spatial measures correlated with success on the slope task differently for each sex.

Modelling of seasonal dynamics of Wetland-Groundwater flow interaction in the Canadian Prairies

NASA Astrophysics Data System (ADS)

Ali, Melkamu; Nussbaumer, Raphaël; Ireson, Andrew; Keim, Dawn

2015-04-01

Wetland-shallow groundwater interaction is studied at the St. Denis National Wildlife Area in Saskatchewan, Canada, located within the northern glaciated prairies of North America. Ponds in the Canadian Prairies are intermittently connected by fill-spill processes in the spring and growing season of some wetter years. The contribution of the ponds and wetlands to groundwater is still a significant research challenge. The objective of this study is to evaluate model's ability to reproduce observed effects of groundwater-wetland interactions including seasonal pattern of shallow groundwater table, intended flow direction and to quantify the depression induced infiltration from the wetland to the surrounding uplands. The integrated surface-wetland-shallow groundwater processes and the changes in land-energy and water balances caused by the flow interaction are simulated using ParFlow-CLM at a small watershed of 1km2 containing both permanent and seasonal wetland complexes. We compare simulated water table depth with piezometers reading monitored by level loggers at the watershed. We also present the strengths and limitations of the model in reproducing observed behaviour of the groundwater table response to the spring snowmelt and summer rainfall. Simulations indicate that the shallow water table at the uphill recovers quickly after major rainfall events in early summer that generates lateral flow to the pond. In late summer, the wetland supplies water to the surrounding upland when the evapotranspiration is higher than the precipitation in which more water from the root zone is up taken by plants. Results also show that Parflow-CLM is able to reasonably simulate the water table patterns response to summer rainfall, while it is insufficient to reproduce the spring snowmelt infiltration which is the most dominant hydrological process in the Prairies.

Direct determination of the driving forces for taurocholate uptake into rat liver plasma membrane vesicles.

PubMed

Duffy, M C; Blitzer, B L; Boyer, J L

1983-10-01

To determine directly the driving forces for bile acid entry into the hepatocyte, the uptake of [3H]taurocholic acid into rat liver plasma membrane vesicles was studied. The membrane preparation contained predominantly right-side-out vesicles, and was highly enriched in plasma membrane marker enzymes. The uptake of taurocholate at equilibrium was inversely related to medium osmolarity, indicating transport into an osmotically sensitive space. In the presence of an inwardly directed sodium gradient (NaCl or sodium gluconate), the initial rate of uptake was rapid and taurocholate was transiently accumulated at a concentration twice that at equilibrium (overshoot). Other inwardly directed cation gradients (K+, Li+, choline+) or the presence of sodium in the absence of a gradient (Na+ equilibrated) resulted in a slower initial uptake rate and did not sustain an overshoot. Bile acids inhibited sodium-dependent taurocholate uptake, whereas bromsulphthalein inhibited both sodium-dependent and sodium-independent uptake and D-glucose had no effect on uptake. Uptake was temperature dependent, with maximal overshoots occurring at 25 degrees C. Imposition of a proton gradient across the vesicle (pHo less than pHi) in the absence of a sodium gradient failed to enhance taurocholate uptake, indicating that double ion exchange (Na+-H+, OH- -anion) is unlikely. Creation of a negative intravesicular potential by altering accompanying anions or by valinomycin-induced K+-diffusion potentials did not enhance taurocholate uptake, suggesting an electroneutral transport mechanism. The kinetics of taurocholate uptake demonstrated saturability with a Michaelis constant at 52 microM and maximum velocity of 4.5 nmol X mg-1 X protein X min-1. These studies provide definitive evidence for a sodium gradient-dependent, carrier-mediated, electrically neutral transport mechanism for hepatic taurocholate uptake. These findings are consistent with a model for bile secretion in which the basolateral enzyme Na+,K+-ATPase provides the driving force for "uphill" bile acid transport by establishing a trans-membrane sodium gradient.

Ecological and life-history traits explain recent boundary shifts in elevation and latitude of western North American songbirds

Treesearch

Sonya K. Auer; David I. King

2014-01-01

Species are expected to move uphill or poleward in response to climate change, yet their distributions show idiosyncratic responses; many species are moving in the predicted direction, but others are not shifting at all or are shifting downhill or towards the equator. Fundamental questions remain about the causes of interspecific variation in range responses and...

Do You Need More Officers? A Comprehensive Benchmarking Formula that Can Help You Make the Case

ERIC Educational Resources Information Center

Sammons, Gregory

2008-01-01

Many campus law enforcement administrators reach a point where they need to request additional staff. Unless the department is awash in extra funding or is in the wake of a major incident that brought significant attention to current manpower, they're likely fighting an uphill battle for growth. The effectiveness of formulas that analyze the size…

Women in Combat: Issues for Congress

DTIC Science & Technology

2015-12-03

report suggested that these changes might have the benefit of expanding career opportunities for women, while increasing flexibility for field...Squad Assessment Tasks Day 1:  Hike 1 kilometer uphill with 28-pound assault pack and personal weapon.  Scramble over 8-foot shipping container...Allow engineers to move forward and fire two breaching shots with Bangalore torpedoes. Day 2:  Hike 7 kilometers with weapons and 59-pound

Language and spatial frames of reference in mind and brain.

PubMed

Gallistel, C R.

2002-08-01

Some language communities routinely use allocentric reference directions (e.g. 'uphill-downhill') where speakers of European languages would use egocentric references ('left-right'). Previous experiments have suggested that the different language groups use different reference frames in non-linguistic tasks involving the recreation of oriented arrays. However, a recent paper argues that manipulating test conditions produces similar effects in monolingual English speakers, and in animals.

In Search of Remedy to Secondary School Dropout Pandemic in Kenya: Role of the Principal

ERIC Educational Resources Information Center

Achoka, J. S. K.

2007-01-01

As a nation, Kenya hopes to achieve Education for All (EFA) by the year 2015. This is an uphill task given the various challenges in the education sector. The year 2015 is also significant globally because it is the target year for the fulfillment of the eight-millennium goals. Kenya looks forward to have her people achieve the millennium goals…

2D Si island nucleation on the Si(111) surface at initial and late growth stages: On the role of step permeability in pyramidlike growth

NASA Astrophysics Data System (ADS)

Rogilo, D. I.; Fedina, L. I.; Kosolobov, S. S.; Ranguelov, B. S.; Latyshev, A. V.

2017-01-01

Initial and late stages of 2D Si island nucleation and growth (2DNG) on extra-large ( 100 μm) and medium size (1-10 μm) atomically flat Si(111)-(7×7) terraces bordered by step bunches have been studied by in situ REM at T =600-750 °С. At first, the layer-by-layer 2DNG takes place on whole terraces and 2D island concentration dependence on deposition rate R corresponds to critical nucleus size i =1. Continuous 2DNG triggers morphological instabilities: elongated pyramidlike waves and separate pyramids emerge on all terraces at T ≤720 °С and T =750 °С, respectively. Both instabilities arise due to the imbalance of uphill/downhill adatom currents related with large Ehrlich-Schwöbel (ES) barriers and permeability of straight [ 11 bar 2 ] -type step edges. However, the first one is initiated by dominant downhill adatom current to distant sinks: bunches, wave's step edges, and "vacancy" islands emerging on terraces due to 2D island coalescence. As a result, top layer size decreases to the critical terrace width λ where 2DNG takes place. From the analysis of λ ∝ R - χ / 2 scaling at T =650 °C, we have found that i increases from i =2 on a three-layer wave to i =6-8 on a six-layer wave. This authenticates the significance of downhill adatom sink to distant steps related to the step permeability. The second instability type at T >720 °C is related to the raising of uphill adatom current due to slightly larger ES barrier for step-up attachment comparing to the step-down one (EES- 0.9 eV [Phys. Rev. Lett. 111 (2013) 036105]). This leads to "second layer" 2D nucleation on top layers, which triggers the growth of separate pyramids. Because of small difference between ES barriers, net uphill/downhill adatom currents are nearly equivalent, and therefore layer coverage distributions of both instabilities display similar linear slopes.

The Chlordecone crisis in the French West Indies : Its fate in soils and water

NASA Astrophysics Data System (ADS)

Voltz, Marc; Cattan, Philippe; Saison, Carine; Berns, Anne E.; Colin, François; Crabit, Armand; Crevoisier, David; Fernandez-Bayo, Jesus; Levillain, Joseph; Pak, Lai-Ting; Samouelian, Anatja; Cabidoche, Yves-Marie

2013-04-01

In the French West Indies, chlordecone (CLD), an organochlorine pesticide, which is highly persistent in the environment, was applied in banana plantations from 1972 to 1993 against the banana weevil Cosmopolites sordidus. Pollution surveys conducted in 2001 by the French Department of Health revealed the presence of chlordecone in soils, rivers, springs over large areas in Guadeloupe and Martinique islands. Contamination of drinking water, food crops, aquatic species by CLD has been observed as well as its presence in blood of men, pregnant women and newborns. There is therefore a large social concern about the extent and evolution of CLD pollution in the French West Indies and its impact on human health and ecosystems. From 2008 to 2012 a multidisciplinary project CHLORDEXCO took place to study the CLD fate in water, soils and the contamination characteristics of aquatic species and food crops. Here, we summarize results obtained on the processes controlling the spatial and temporal patterns of soil and water contamination at the scale of the banana cropping area in Guadeloupe and of the Perou catchment. The main soils in the contaminated areas are andosols and nitisols and formed from the weathering of volcanic ashes. They have a high organic carbon content and high content of secondary minerals, allophane for andosols and halloysite for nitisols. An analysis of the spatial distribution of CLD in soil over 1045 field plots showed that the soil type had a strong impact. Andosols, with a high sorption capacity (Koc 20 000 L/kg), had the highest CLD concentrations and stocks, unlike Nitisols, which had 10-fold lower sorption capacities. A significant « farm effect », due to between-farm variations of application times and amounts, was also noticed. The observed stocks of CLD clearly correspond to the accumulation in soil of successive treatments and thereby confirm the high persistence of CLD in soil also observed in incubation studies in soil microcosms. Soil column studies of the transport of aged CLD however showed that CLD concentration in percolation water varied little (5 to 10 μg/L) and were of same magnitude for both soils although their sorption properties and hydrodynamic behaviours differed with larger macropore flow in the andosols. At catchment scale, contamination of surface waters was permanent with CLD concentrations one order of magnitude less than in percolation water. Temporal variations of contamination were due to dilution effects caused by water from uncontaminated uphill areas. CLD concentrations were highest in base flow indicating that the main pathway of applied CLD to surface waters is by percolation and groundwater flow. In conclusion, contamination of soil and water in the banana cropped areas of the French West Indies is general and permanent. If no soil remediation strategies can be elaborated this severe environmental contamination will last over centuries as estimated by Cabidoche et al. (2009, Environ. Poll., 57, 1697-1705). Since CLD propagates mainly by subsurface flow, buffer strips, usually recommended in many regions to limit the pollution of water by pesticides, will not be useful.

Geographic location, network patterns and population distribution of rural settlements in Greece

NASA Astrophysics Data System (ADS)

Asimakopoulos, Avraam; Mogios, Emmanuel; Xenikos, Dimitrios G.

2016-10-01

Our work addresses the problem of how social networks are embedded in space, by studying the spread of human population over complex geomorphological terrain. We focus on villages or small cities up to a few thousand inhabitants located in mountainous areas in Greece. This terrain presents a familiar tree-like structure of valleys and land plateaus. Cities are found more often at lower altitudes and exhibit preference on south orientation. Furthermore, the population generally avoids flat land plateaus and river beds, preferring locations slightly uphill, away from the plateau edge. Despite the location diversity regarding geomorphological parameters, we find certain quantitative norms when we examine location and population distributions relative to the (man-made) transportation network. In particular, settlements at radial distance ℓ away from road network junctions have the same mean altitude, practically independent of ℓ ranging from a few meters to 10 km. Similarly, the distribution of the settlement population at any given ℓ is the same for all ℓ. Finally, the cumulative distribution of the number of rural cities n(ℓ) is fitted to the Weibull distribution, suggesting that human decisions for creating settlements could be paralleled to mechanisms typically attributed to this particular statistical distribution.

Problems of older persons using a wheeled walker.

PubMed

Lindemann, Ulrich; Schwenk, Michael; Klenk, Jochen; Kessler, Max; Weyrich, Michael; Kurz, Franziska; Becker, Clemens

2016-04-01

Wheeled walkers (WWs) are used to improve mobility and for fall prevention in older persons, but not all users are satisfied with the usability of WWs. Intelligent WWs are being developed to improve the usability. The aim of this study was to support the development of intelligent WWs by investigating possible problems of using a WW. This study investigated 22 geriatric in-patients (median age 82 years) with and without their WW while opening a door against the direction of walking and passing through. Other possible problems when using WWs were identified by interview. Walking through the door was faster without than with using the WW (8.71 versus 12.86 s, p < 0.001), while interference between door and WW was documented in 41 of 44 (93 %) cases. Backward walking performance was better when using a WW with regard to gait speed, step width and walk ratio (all p < 0.002). Most referred problems when using a WW were walking downhill (83 %) and uphill (77 %) and obstacle crossing in general (77 %). Problems with opening a door against the direction of walking and the optimization of downhill and uphill walking as well as obstacle crossing should be regarded when developing an intelligent WW.

Lattice Boltzmann modeling of self-propelled Leidenfrost droplets on ratchet surfaces

DOE PAGES

Li, Qing; Kang, Qinjun J.; Francois, Marianne M.; ...

2016-10-09

Here in this paper, the self-propelled motion of Leidenfrost droplets on ratchet surfaces is numerically investigated with a thermal multiphase lattice Boltzmann model with liquid-vapor phase change. The capability of the model for simulating evaporation is validated via the D 2 law. Using the model, we first study the performances of Leidenfrost droplets on horizontal ratchet surfaces. It is numerically shown that the motion of self-propelled Leidenfrost droplets on ratchet surfaces is owing to the asymmetry of the ratchets and the vapor flows beneath the droplets. It is found that the Leidenfrost droplets move in the direction toward the slowlymore » inclined side from the ratchet peaks, which agrees with the direction of droplet motion in experiments [Linke et al., Phys. Rev. Lett., 2006, 96, 154502]. Moreover, the influences of the ratchet aspect ratio are investigated. For the considered ratchet surfaces, a critical value of the ratchet aspect ratio is approximately found, which corresponds to the maximum droplet moving velocity. Furthermore, the processes that the Leidenfrost droplets climb uphill on inclined ratchet surfaces are also studied. Lastly, numerical results show that the maximum inclination angle at which a Leidenfrost droplet can still climb uphill successfully is affected by the initial radius of the droplet.« less

Lattice Boltzmann modeling of self-propelled Leidenfrost droplets on ratchet surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Qing; Kang, Qinjun J.; Francois, Marianne M.

Here in this paper, the self-propelled motion of Leidenfrost droplets on ratchet surfaces is numerically investigated with a thermal multiphase lattice Boltzmann model with liquid-vapor phase change. The capability of the model for simulating evaporation is validated via the D 2 law. Using the model, we first study the performances of Leidenfrost droplets on horizontal ratchet surfaces. It is numerically shown that the motion of self-propelled Leidenfrost droplets on ratchet surfaces is owing to the asymmetry of the ratchets and the vapor flows beneath the droplets. It is found that the Leidenfrost droplets move in the direction toward the slowlymore » inclined side from the ratchet peaks, which agrees with the direction of droplet motion in experiments [Linke et al., Phys. Rev. Lett., 2006, 96, 154502]. Moreover, the influences of the ratchet aspect ratio are investigated. For the considered ratchet surfaces, a critical value of the ratchet aspect ratio is approximately found, which corresponds to the maximum droplet moving velocity. Furthermore, the processes that the Leidenfrost droplets climb uphill on inclined ratchet surfaces are also studied. Lastly, numerical results show that the maximum inclination angle at which a Leidenfrost droplet can still climb uphill successfully is affected by the initial radius of the droplet.« less

Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding

PubMed Central

Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank

2012-01-01

Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power. PMID:23112598

Harvesting energy from the counterbalancing (weaving) movement in bicycle riding.

PubMed

Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank

2012-01-01

Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

High Intensity Interval Training Improves Physical Performance and Frailty in Aged Mice.

PubMed

Seldeen, Kenneth Ladd; Lasky, Ginger; Leiker, Merced Marie; Pang, Manhui; Personius, Kirkwood Ely; Troen, Bruce Robert

2018-03-14

Sarcopenia and frailty are highly prevalent in older individuals, increasing the risk of disability and loss of independence. High intensity interval training (HIIT) may provide a robust intervention for both sarcopenia and frailty by achieving both strength and endurance benefits with lower time commitments than other exercise regimens. To better understand the impacts of HIIT during aging, we compared 24-month-old C57BL/6J sedentary mice with those that were administered 10-minute uphill treadmill HIIT sessions three times per week over 16 weeks. Baseline and end point assessments included body composition, physical performance, and frailty based on criteria from the Fried physical frailty scale. HIIT-trained mice demonstrated dramatic improvement in grip strength (HIIT 10.9% vs -3.9% in sedentary mice), treadmill endurance (32.6% vs -2.0%), and gait speed (107.0% vs 39.0%). Muscles from HIIT mice also exhibited greater mass, larger fiber size, and an increase in mitochondrial biomass. Furthermore, HIIT exercise led to a dramatic reduction in frailty scores in five of six mice that were frail or prefrail at baseline, with four ultimately becoming nonfrail. The uphill treadmill HIIT exercise sessions were well tolerated by aged mice and led to performance gains, improvement in underlying muscle physiology, and reduction in frailty.

Shake, Rupture And Flow: Hydraulic Constraints On The Formation Of Europa’s Chaos

NASA Astrophysics Data System (ADS)

Schmidt, Britney E.; Gooch, B. T.; Blankenship, D. D.; Soderlund, K. M.

2012-10-01

Europa’s chaos terrains may have formed above shallow water lenses formed by melting of the upper ice shell with ascending thermo-compositional plumes. A key factor in the creation of chaos terrain may be dramatic disruption and collapse of the ice lid above the forming melt lens along with potentially violent mixing upon its rupture; this is analogous to the collapse of terrestrial ice shelves in which massive ice bodies disintegrate in a few days. At Thera Macula, there is evidence for modification by water immediately external to the scarp that bounds the collapsed region. Since water runs either subaerially down hill or from high pressure to low when below or within ice, the swollen appearance of bands entering Thera Macula, which are uphill in terms of hydraulic and topographic gradients, raises the possibility that this steep scarp represents the place where the lens initially broke. As the ice lid ruptures, the overpressure within the lens may create sufficient pressure within the fracture to drive water through it, allowing water to escape into and modify surrounding terrain. Similar effects are seen when aquifers or subglacial water sources are tapped: water flows up the pipe until the pressure in the water body is relieved and the hydraulic “pressure head” in the pipe is lowered. We have modeled the hydraulic potential associated with a rupturing lens in order to investigate the range of parameters for overpressure, fracture width, and lid thickness that could produce such modification as is observed at Thera Macula. These place important constraints on the pressure within the lens and the energetics of a collapse event. These estimates may explain how ice masses within chaos are initially disrupted and provide a means for quantifying the vigor of surface-subsurface mixing that could be critical to Europa’s habitability.

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

PubMed

Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

2017-09-19

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox processes of their own. We dissect the thermodynamics and kinetics of electron bifurcation in Nfn and find that the key features of electron bifurcation are (1) spatially separated transfer pathways that diverge from a two-electron donor, (2) one thermodynamically uphill and one downhill redox pathway, with a large negative shift in the donor's reduction potential after departure of the first electron, and (3) electron tunneling and activation factors that enable bifurcation, producing a 1:1 partitioning of electrons onto the two pathways. Electron bifurcation is found in the CO 2 reducing pathways of methanogenic archaea, in the hydrogen pathways of hydrogenases, in the nitrogen fixing pathway of Fix, and in the mitochondrial charge transfer chain of complex III, cytochrome bc 1 . While crossed potentials may offer the biological advantage of producing tightly regulated high energy reactive species, neither kinetic nor thermodynamic considerations mandate crossed potentials to generate successful electron bifurcation. Taken together, the theoretical framework established here, focusing on the underpinning electron tunneling barriers and activation free energies, explains the logic of electron bifurcation that enables energy conversion and conservation in Nfn, points toward bioinspired schemes to execute multielectron redox chemistry, and establishes a roadmap for examining novel electron bifurcation networks in nature.

A thermodynamic study of electroneutral K-Cl cotransport in pH- and volume-clamped low K sheep erythrocytes with normal and low internal magnesium.

PubMed

Lauf, P K; Adragna, N C

1996-10-01

Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K-Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato-2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl.

A thermodynamic study of electroneutral K-Cl cotransport in pH- and volume-clamped low K sheep erythrocytes with normal and low internal magnesium

PubMed Central

1996-01-01

Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K- Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato- 2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl. PMID:8894982

STATISTICAL RELATIONAL LEARNING AND SCRIPT INDUCTION FOR TEXTUAL INFERENCE

DTIC Science & Technology

2017-12-01

E 23rd St Austin , TX 78712 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) Air Force Research ...Processing (EMNLP), Austin , TX , 2016. 
 Pichotta, K. and Mooney, R.J., “Using Sentence-Level LSTM Language Models for Script Inference,” Proceedings of the...on Uphill Battles in Language Processing, Austin , TX , 2016. 
 Rajani, N., and Mooney, R. J., “Stacked Ensembles of Information Extractors for

The efficiency coefficient of the rat heart and muscular system after physical training and hypokinesia

NASA Technical Reports Server (NTRS)

Alyukhin, Y. S.; Davydov, A. F.

1982-01-01

The efficiency of an isolated heart did not change after prolonged physical training of rats for an extreme load. The increase in oxygen consumption by the entire organism in 'uphill' running as compared to the resting level in the trained rats was 14% lower than in the control animals. Prolonged hypokinesia of the rats did not elicit a change in the efficiency of the isolated heart.

The Battle of Attu and the Aleutian Island Campaign

DTIC Science & Technology

2014-05-22

minutes. The Americans, however, had quickly relocated to high ground above Holtz Bay. Colonel Hartl called for a barrage of naval gunfire from the...destroyer Phelps followed by close air support from the aircraft carrier Nassau. Hartl pushed Northern Force uphill through heavy gunfire attacking the...Northern Force was able to drive the enemy back. Hartl sent a message to General Brown stating, “Have captured last high ground before West Arm of

FLYING-WATER Renewables-H2-H2O TERRAFORMING: PERMANENT Drought(s)-Elimination FOREVER!!!

NASA Astrophysics Data System (ADS)

Ertl, G.; Alefeld, G.; Youdelis, W.; Radd, H.; Oertle, G.; Siegel, Edward

2011-03-01

"H2O H2O everywhere; ne'er a drop to drink"[Coleridge(1798)]; now: "H2 H2 everywhere; STILL ne'er a drop to drink": ONLY H2 (or methane CH4) can be FLYING-WATER(F-W) chemical-rain-in-pipelines Hindenberg-effect (H2-UP;H2O-DOWN): {O/H2O}=[16]/[18] 90 % ; O already in air uphill; NO H2O pumping need! In global-warming driven H2O-starved glacial-melting world, rescue is possible ONLY by Siegel [{3rd Intl. Conf. Alt.-Energy }(1980)-vol.5/p.459!!!] Renewables-H2-H2O purposely flexible versatile agile customizable scaleable retrofitable integrated operating-system. Rosenfeld[Science 315,1396(3/9/2007)]-Biello [Sci.Am.(3/9/2007)] crucial geomorph-ology which ONLY maximal-buoyancy H2 can exploit, to again make "Mountains into Fountains", ``upthrust rocks trapping the clouds to precipitate their rain/snow/H2O'': "terraforming"(and ocean-rebasificaton!!!) Siegel proprietary magnetic-hydrogen-valve (MHV) permits H2 flow in already in-ground dense BCC/ferritic-steels pipelines-network (NO new infrastructure) counters Tromp[Science 300,1740(2003)] dire warning of global-pandemics (cancers/ blindness/famine) Hydrogen-economy CATASTROPHIC H2 ozone-layer destruction sobering cavat to dangerous H2-automotion-economy panacea hype!!!

Warming and the dependence of limber pine (Pinus flexilis) establishment on summer soil moisture within and above its current elevation range

USGS Publications Warehouse

Moyes, Andrew B.; Castanha, Cristina; Germino, Matthew J.; Kueppers, Lara M.

2013-01-01

Continued changes in climate are projected to alter the geographic distributions of plant species, in part by affecting where individuals can establish from seed. We tested the hypothesis that warming promotes uphill redistribution of subalpine tree populations by reducing cold limitation at high elevation and enhancing drought stress at low elevation. We seeded limber pine (Pinus flexilis) into plots with combinations of infrared heating and water addition treatments, at sites positioned in lower subalpine forest, the treeline ecotone, and alpine tundra. In 2010, first-year seedlings were assessed for physiological performance and survival over the snow-free growing season. Seedlings emerged in midsummer, about 5–8 weeks after snowmelt. Low temperature was not observed to limit seedling photosynthesis or respiration between emergence and October, and thus experimental warming did not appear to reduce cold limitation at high elevation. Instead, gas exchange and water potential from all sites indicated a prevailing effect of summer moisture stress on photosynthesis and carbon balance. Infrared heaters raised soil growing degree days (base 5 °C, p p 3 m-3 consistently corresponded with moderate and severe indications of drought stress in midday stem water potential, stomatal conductance, photosynthesis, and respiration. Seedling survival was greater in watered plots than in heated plots (p = 0.01), and negatively related to soil growing degree days and duration of exposure to θ 3 m-3 in a stepwise linear regression model (p < 0.0001). We concluded that seasonal moisture stress and high soil surface temperature imposed a strong limitation to limber pine seedling establishment across a broad elevation gradient, including at treeline, and that these limitations are likely to be enhanced by further climate warming.

Rapid water transportation through narrow one-dimensional channels by restricted hydrogen bonds.

PubMed

Ohba, Tomonori; Kaneko, Katsumi; Endo, Morinobu; Hata, Kenji; Kanoh, Hirofumi

2013-01-29

Water plays an important role in controlling chemical reactions and bioactivities. For example, water transportation through water channels in a biomembrane is a key factor in bioactivities. However, molecular-level mechanisms of water transportation are as yet unknown. Here, we investigate water transportation through narrow and wide one-dimensional (1D) channels on the basis of water-vapor adsorption rates and those determined by molecular dynamics simulations. We observed that water in narrow 1D channels was transported 3-5 times faster than that in wide 1D channels, although the narrow 1D channels provide fewer free nanospaces for water transportation. This rapid transportation is attributed to the formation of fewer hydrogen bonds between water molecules adsorbed in narrow 1D channels. The water-transportation mechanism provides the possibility of rapid communication through 1D channels and will be useful in controlling reactions and activities in water systems.

Climatotherapy in Japan: a pilot study

NASA Astrophysics Data System (ADS)

Kanayama, Hitomi; Kusaka, Yukinori; Hirai, Takayoshi; Inoue, Hiroyuki; Agishi, Yuko; Schuh, Angela

2017-12-01

Twenty-nine urban inhabitants participated in a half-day climatotherapy programme at the moderate mountain area and lowland area in the northwest part of the main island of Japan. The current study was aimed to investigate physically and mentally the objective and subjective influence of our short programme, which was a prospective pilot study of single intervention. Blood pressure was significantly descended during terrain cure at the uphill mountain path and returned after fresh-air rest cure, while there was no significant change throughout the programme at lowland flat path. Heart rate was significantly ascended and descended at both area, and more clearly changed at the mountain path. Profile of Mood Status brief form Japanese version administered before and after our half-day programme. Age adjusted T score of negative subscales, `tension-anxiety', `depression', `anger-hostility', `fatigue' and `confusion' were significantly lower after climatotherapy at both sites. Whereas, there was no significant change concerning `vigour' score. This short-version climatotherapy programme has been designed for people without enough time for long stay at health resort. It turned out our half-day climatotherapy programme contribute to mood status improvement. In addition, repeated practice of our short-version programme including endurance exercise with cool body shell using uphill path can be expected that blood pressure will go toward the normal range and heart rate will decrease both in usual time and during exercise. Therefore, health benefits can be expected of this climatotherapy programme.

Biomechanical pole and leg characteristics during uphill diagonal roller skiing.

PubMed

Lindinger, Stefan Josef; Göpfert, Caroline; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-11-01

Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9 degrees; 11 km/h). Performance was correlated to cycle length (r = 0.77; P < 0.05), relative leg swing (r = 0.71), and gliding time (r = 0.74), hip flexion range of motion (ROM) during swing (r = 0.73) and knee extension ROM during gliding (r = 0.71). Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r= -0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.

Electric bicycles as a new active transportation modality to promote health.

PubMed

Gojanovic, Boris; Welker, Joris; Iglesias, Katia; Daucourt, Chantal; Gremion, Gérald

2011-11-01

Electrically assisted bicycles (EAB) are an emerging transportation modality favored for environmental reasons. Some physical effort is required to activate the supporting engine, making it a potential active commuting option. We hypothesized that using an EAB in a hilly city allows sedentary subjects to commute comfortably, while providing a sufficient effort for health-enhancing purposes. Sedentary subjects performed four different trips at a self-selected pace: walking 1.7 km uphill from the train station to the hospital (WALK), biking 5.1 km from the lower part of town to the hospital with a regular bike (BIKE), or EAB at two different power assistance settings (EAB high, EAB std). HR, oxygen consumption, and need to shower were recorded. Eighteen sedentary subjects (12 female, 6 male) age 36 ± 10 yr were included, with V·O 2max of 39.4 ± 5.4 mL·min(-1)·kg(-1). Time to complete the course was 22 (WALK), 19 (EAB high), 21 (EAB std), and 30 (BIKE) min. Mean %V·O 2max was 59.0%, 54.9%, 65.7%, and 72.8%. Mean %HRmax was 71.5%, 74.5%, 80.3%, and 84.0%. There was no significant difference between WALK and EAB high, but all other comparisons were different (P < 0.05). Two subjects needed to shower after EAB high, 3 needed to shower after WALK, 8 needed to shower after EAB std, and all 18 needed to shower after BIKE. WALK and EAB high elicited 6.5 and 6.1 METs (no difference), whereas it was 7.3 and 8.2 for EAB std and BIKE. EAB is a comfortable and ecological transportation modality, helping sedentary people commute to work and meet physical activity guidelines. Subjects appreciated ease of use and mild effort needed to activate the engine support climbing hills, without the need to shower at work. EAB can be promoted in a challenging urban environment to promote physical activity and mitigate pollution issues.

Water pumps.

PubMed

Loo, Donald D F; Wright, Ernest M; Zeuthen, Thomas

2002-07-01

The transport of water across epithelia has remained an enigma ever since it was discovered over 100 years ago that water was transported across the isolated small intestine in the absence of osmotic and hydrostatic pressure gradients. While it is accepted that water transport is linked to solute transport, the actual mechanisms are not well understood. Current dogma holds that active ion transport sets up local osmotic gradients in the spaces between epithelial cells, the lateral intercellular spaces, and this in turn drives water transport by local osmosis. In the case of the small intestine, which in humans absorbs about 8 l of water a day, there is no direct evidence for either local osmosis or aquaporin gene expression in enterocytes. Intestinal water absorption is greatly enhanced by glucose, and this is the basis for oral rehydration therapy in patients with secretory diarrhoea. In our studies of the intestinal brush border Na+-glucose cotransporter we have obtained evidence that there is a direct link between the transport of Na+, glucose and water transport, i.e. there is cotransport of water along with Na+ and sugar, that will account for about 50 % of the total water transport across the human intestinal brush border membrane. In this short review we summarize the evidence for water cotransport and propose how this occurs during the enzymatic turnover of the transporter. This is a general property of cotransporters and so we expect that this may have wider implications in the transport of water and other small polar molecules across cell membranes in animals and plants.

Water pumps

PubMed Central

Loo, Donald D F; Wright, Ernest M; Zeuthen, Thomas

2002-01-01

The transport of water across epithelia has remained an enigma ever since it was discovered over 100 years ago that water was transported across the isolated small intestine in the absence of osmotic and hydrostatic pressure gradients. While it is accepted that water transport is linked to solute transport, the actual mechanisms are not well understood. Current dogma holds that active ion transport sets up local osmotic gradients in the spaces between epithelial cells, the lateral intercellular spaces, and this in turn drives water transport by local osmosis. In the case of the small intestine, which in humans absorbs about 8 l of water a day, there is no direct evidence for either local osmosis or aquaporin gene expression in enterocytes. Intestinal water absorption is greatly enhanced by glucose, and this is the basis for oral rehydration therapy in patients with secretory diarrhoea. In our studies of the intestinal brush border Na+-glucose cotransporter we have obtained evidence that there is a direct link between the transport of Na+, glucose and water transport, i.e. there is cotransport of water along with Na+ and sugar, that will account for about 50 % of the total water transport across the human intestinal brush border membrane. In this short review we summarize the evidence for water cotransport and propose how this occurs during the enzymatic turnover of the transporter. This is a general property of cotransporters and so we expect that this may have wider implications in the transport of water and other small polar molecules across cell membranes in animals and plants. PMID:12096049

Effect of Compression Garments on Physiological Responses After Uphill Running.

PubMed

Struhár, Ivan; Kumstát, Michal; Králová, Dagmar Moc

2018-03-01

Limited practical recommendations related to wearing compression garments for athletes can be drawn from the literature at the present time. We aimed to identify the effects of compression garments on physiological and perceptual measures of performance and recovery after uphill running with different pressure and distributions of applied compression. In a random, double blinded study, 10 trained male runners undertook three 8 km treadmill runs at a 6% elevation rate, with the intensity of 75% VO2max while wearing low, medium grade compression garments and high reverse grade compression. In all the trials, compression garments were worn during 4 hours post run. Creatine kinase, measurements of muscle soreness, ankle strength of plantar/dorsal flexors and mean performance time were then measured. The best mean performance time was observed in the medium grade compression garments with the time difference being: medium grade compression garments vs. high reverse grade compression garments. A positive trend in increasing peak torque of plantar flexion (60º·s-1, 120º·s-1) was found in the medium grade compression garments: a difference between 24 and 48 hours post run. The highest pain tolerance shift in the gastrocnemius muscle was the medium grade compression garments, 24 hour post run, with the shift being +11.37% for the lateral head and 6.63% for the medial head. In conclusion, a beneficial trend in the promotion of running performance and decreasing muscle soreness within 24 hour post exercise was apparent in medium grade compression garments.

The aerobic respiratory chain of the acidophilic archaeon Ferroplasma acidiphilum: A membrane-bound complex oxidizing ferrous iron.

PubMed

Castelle, Cindy J; Roger, Magali; Bauzan, Marielle; Brugna, Myriam; Lignon, Sabrina; Nimtz, Manfred; Golyshina, Olga V; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne

2015-08-01

The extremely acidophilic archaeon Ferroplasma acidiphilum is found in iron-rich biomining environments and is an important micro-organism in naturally occurring microbial communities in acid mine drainage. F. acidiphilum is an iron oxidizer that belongs to the order Thermoplasmatales (Euryarchaeota), which harbors the most extremely acidophilic micro-organisms known so far. At present, little is known about the nature or the structural and functional organization of the proteins in F. acidiphilum that impact the iron biogeochemical cycle. We combine here biochemical and biophysical techniques such as enzyme purification, activity measurements, proteomics and spectroscopy to characterize the iron oxidation pathway(s) in F. acidiphilum. We isolated two respiratory membrane protein complexes: a 850 kDa complex containing an aa3-type cytochrome oxidase and a blue copper protein, which directly oxidizes ferrous iron and reduces molecular oxygen, and a 150 kDa cytochrome ba complex likely composed of a di-heme cytochrome and a Rieske protein. We tentatively propose that both of these complexes are involved in iron oxidation respiratory chains, functioning in the so-called uphill and downhill electron flow pathways, consistent with autotrophic life. The cytochrome ba complex could possibly play a role in regenerating reducing equivalents by a reverse ('uphill') electron flow. This study constitutes the first detailed biochemical investigation of the metalloproteins that are potentially directly involved in iron-mediated energy conservation in a member of the acidophilic archaea of the genus Ferroplasma. Copyright © 2015 Elsevier B.V. All rights reserved.

Judgments of visually perceived eye level (VPEL) in outdoor scenes: effects of slope and height.

PubMed

O'Shea, Robert P; Ross, Helen E

2007-01-01

When one looks up a hill from below, its peak appears lower than it is; when one looks at a hill across a valley from another peak, the peak of that hill appears higher than it is. These illusions have sometimes been explained by assuming that the subjective horizontal is assimilated to the nearby slope: when looking up a slope, the subjective horizontal is raised, diminishing the height of the peak above the subjective horizontal, and making the peak appear lower than it is. When looking down a slope towards another hill, the subjective horizontal is lowered, increasing the height of that hill above the subjective horizontal, and making its peak appear higher than it is. To determine subjective horizontals we measured visually perceived eye levels (VPELs) in 21 real-world scenes on a range of slopes. We found that VPEL indeed assimilates by about 40% to slopes between 7 degrees downhill and 7 degrees uphill. For larger uphill slopes up to 23 degrees, VPEL asymptotes at about 4.5 degrees. For larger downhill slopes, the assimilation of VPEL diminishes, and at 23 degrees is raised by about 1 degree. These results are consistent with the assimilation explanation of the illusions if we assume that steep downhill slopes lose their effectiveness by being out of view. We also found that VPEL was raised when viewing from a height, in comparison with ground-level views, perhaps because the perceived slope increases with viewing height.

Does water content or flow rate control colloid transport in unsaturated porous media?

PubMed

Knappenberger, Thorsten; Flury, Markus; Mattson, Earl D; Harsh, James B

2014-04-01

Mobile colloids can play an important role in contaminant transport in soils: many contaminants exist in colloidal form, and colloids can facilitate transport of otherwise immobile contaminants. In unsaturated soils, colloid transport is, among other factors, affected by water content and flow rate. Our objective was to determine whether water content or flow rate is more important for colloid transport. We passed negatively charged polystyrene colloids (220 nm diameter) through unsaturated sand-filled columns under steady-state flow at different water contents (effective water saturations Se ranging from 0.1 to 1.0, with Se = (θ - θr)/(θs - θr)) and flow rates (pore water velocities v of 5 and 10 cm/min). Water content was the dominant factor in our experiments. Colloid transport decreased with decreasing water content, and below a critical water content (Se < 0.1), colloid transport was inhibited, and colloids were strained in water films. Pendular ring and water film thickness calculations indicated that colloids can move only when pendular rings are interconnected. The flow rate affected retention of colloids in the secondary energy minimum, with less colloids being trapped when the flow rate increased. These results confirm the importance of both water content and flow rate for colloid transport in unsaturated porous media and highlight the dominant role of water content.

FLYING-WATER Renewables-H2-H2O TERRAFORMING: PERMANENT ETERNAL Drought(s)-Elimination FOREVER!!!

NASA Astrophysics Data System (ADS)

Wignall, J.; Lyons, Marv; Ertl, G.; Alefeld, Georg; Youdelis, W.; Radd, H.; Oertle, G.; Siegel, Edward

2013-03-01

''H2O H2O everywhere; ne'er a drop to drink''[Coleridge(1798)] now: ''H2 H2 everywhere; STILL ne'er a drop to drink'': ONLY H2 (or methane CH4) can be FLYING-WATER(F-W) chemical-rain-in-pipelines Hindenberg-effect (H2-UP;H2O-DOWN): { ∖{}O/H2O{ ∖}} =[16]/[18] ∖sim 90{ ∖%} O already in air uphill; NO H2O pumping need! In global-warming driven H2O-starved glacial-melting world, rescue is possible ONLY by Siegel [ ∖underline {3rd Intl. Conf. Alt.-Energy }(1980)-vol.5/p.459!!!] Renewables-H2-H2O purposely flexible versatile agile customizable scaleable retrofitable integrated operating-system. Rosenfeld[Science 315,1396(3/9/2007)]-Biello [Sci.Am.(3/9 /2007)] crucial geomorphology which ONLY maximal-buoyancy H2 can exploit, to again make ''Mountains into Fountains'', ``upthrust rocks trapping the clouds to precipitate their rain/snow/H2O'': ''terraforming''(and ocean-rebasificaton!!!) ONLY VIA Siegel[APS March MTGS.:1960s-2000ss) DIFFUSIVE-MAGNETORESISTANCE (DMR) proprietary MAGNETIC-HYDROGEN-VALVE(MHV) ALL-IMPORTANT PRECLUDED RADIAL-diffusion, permitting ONLY AXIAL-H2-BALLISTIC-flow (``G.A''.''/DoE''/''Terrapower''/''Intellectual-Ventures''/ ''Gileland''/ ''Myhrvold''/''Gates'' ``ARCHIMEDES'') in ALREADY IN-ground dense BCC/ferritic-steels pipelines-network (NO new infrastructure) counters Tromp[Science 300,1740(2003)] dire warning of global-pandemics (cancers/ blindness/ famine)

The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study.

PubMed

Kao, Huei Chu; Lin, Chiuhsiang Joe; Lee, Yung Hui; Chen, Su Huang

2015-01-01

The purpose of this study was to explore the effects of direction of exertion (DOE) (pushing, pulling), path (walking in a straight line, turning left, walking uphill), and load placement (LP) (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis) on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull), 3 paths, and 18 load placements (indicated by X, Y and Z axes). A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG) data of four muscles collected bilaterally as follows: Left (L) and right (R) trapezius (TR), flexor digitorum superficialis (FDS), extensor digitorum (ED), and erector spinae (ES) and subjective ratings of perceived exertion (RPE). Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7%) than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%). A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of backward pulling, and that uphill paths should be avoided in the design of work environments. In terms of distribution of the load in a nursing cart, heavier materials should be positioned at bottom of the cabinet, centered on the horizontal plane and close to the handle, to reduce the physical load of the nursing staff.

The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study

PubMed Central

Kao, Huei Chu; Lin, Chiuhsiang Joe; Lee, Yung Hui; Chen, Su Huang

2015-01-01

The purpose of this study was to explore the effects of direction of exertion (DOE) (pushing, pulling), path (walking in a straight line, turning left, walking uphill), and load placement (LP) (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis) on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull), 3 paths, and 18 load placements (indicated by X, Y and Z axes). A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG) data of four muscles collected bilaterally as follows: Left (L) and right (R) trapezius (TR), flexor digitorum superficialis (FDS), extensor digitorum (ED), and erector spinae (ES) and subjective ratings of perceived exertion (RPE). Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7%) than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%). A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of backward pulling, and that uphill paths should be avoided in the design of work environments. In terms of distribution of the load in a nursing cart, heavier materials should be positioned at bottom of the cabinet, centered on the horizontal plane and close to the handle, to reduce the physical load of the nursing staff. PMID:26485039

Secondary health conditions and spinal cord injury: an uphill battle in the journey of care.

PubMed

Guilcher, Sara J T; Craven, B Cathy; Lemieux-Charles, Louise; Casciaro, Tiziana; McColl, Mary Ann; Jaglal, Susan B

2013-06-01

To understand the journey of care in the prevention and management of secondary health conditions (SHCs) following spinal cord injury (SCI). This was a case study design with 'Ontario' as the case. The Network Episode Model was used as the conceptual framework. Data sources included in depth interviews with persons with SCI, care providers, and policy and decision makers. Document analysis was also conducted on relevant materials and policies. Key informants were selected by purposeful sampling as well as snowball sampling to provide maximum variation. Data analysis was an iterative process and involved descriptive and interpretive analyses. A coding structure was developed based on the conceptual framework which allowed for free nodes when emerging ideas or themes were identified. Twenty-eight individuals were interviewed (14 persons with SCI and 14 persons representing care providers, community advocacy organization representatives, system service delivery administrators and policy-makers). A major over-arching domain that emerged from the data was the concept of 'fighting'. Eleven themes were identified: at the micro-individual level: (i) social isolation and system abandonment, (ii) funding and equitable care, (iii) bounded freedom and self-management; at the meso care provider level: (iv) gender and caregiving strain, (v) help versus disempowerment, (vi) holistic care-thinking outside the box, (vii) poor communication and coordination of care; and at the macro health system level: (viii) fight for access and availability, (ix) models of care tensions, (x) private versus public tensions and (xi) rigid rules and policies. Findings suggest that the journey is challenging and a persistent uphill struggle for persons with SCI, care providers, and community-based advocates. If we are to make significant gains in minimizing the incidence and severity of SHCs, we need to tailor efforts at the health system level. • Secondary health conditions are problematic for individuals with a spinal cord injury (SCI). • This study aimed to understand the journey of care in the prevention and management of secondary health conditions (SHCs) following SCI. • Findings suggest that the journey is challenging and a persistent uphill struggle for persons with SCI, care providers, and community-based advocates. • All stakeholders involved recognized the disparities in access to care and resources that exist within the system. We recommend that if we are to make significant gains in minimizing the incidence and severity of SHCs, we need to tailor efforts at the health system level.

The Mechanism of Isotonic Water Transport

PubMed Central

Diamond, Jared M.

1964-01-01

The mechanism by which active solute transport causes water transport in isotonic proportions across epithelial membranes has been investigated. The principle of the experiments was to measure the osmolarity of the transported fluid when the osmolarity of the bathing solution was varied over an eightfold range by varying the NaCl concentration or by adding impermeant non-electrolytes. An in vitro preparation of rabbit gall bladder was suspended in moist oxygen without an outer bathing solution, and the pure transported fluid was collected as it dripped off the serosal surface. Under all conditions the transported fluid was found to approximate an NaCl solution isotonic to whatever bathing solution used. This finding means that the mechanism of isotonic water transport in the gall bladder is neither the double membrane effect nor co-diffusion but rather local osmosis. In other words, active NaCl transport maintains a locally high concentration of solute in some restricted space in the vicinity of the cell membrane, and water follows NaCl in response to this local osmotic gradient. An equation has been derived enabling one to calculate whether the passive water permeability of an organ is high enough to account for complete osmotic equilibration of actively transported solute. By application of this equation, water transport associated with active NaCl transport in the gall bladder cannot go through the channels for water flow under passive conditions, since these channels are grossly too impermeable. Furthermore, solute-linked water transport fails to produce the streaming potentials expected for water flow through these passive channels. Hence solute-linked water transport does not occur in the passive channels but instead involves special structures in the cell membrane, which remain to be identified. PMID:14212146

Structure-dependent water transport across nanopores of carbon nanotubes: toward selective gating upon temperature regulation.

PubMed

Zhao, Kuiwen; Wu, Huiying

2015-04-28

Determining water structure in nanopores and its influence on water transport behaviour is of great importance for understanding and regulating the transport across nanopores. Here we report an ultrafast-slow flow transition phenomenon for water transport across nanopores of carbon nanotubes owing to the change in water structure in nanopores induced by temperature. By performing extensive molecular dynamics simulations, we show the dependence of water transport behaviours on water structures. Our results indicate that owing to the change in water structure in nanopores, water flux across nanopores with certain pore sizes decreases sharply (nearly 3 orders of magnitude) with the decreasing temperature. This phenomenon is very sensitive to the pore size. The threshold temperatures for the occurrence of the ultrafast-slow flow transition for water transport are also determined for various pore sizes. These findings suggest a novel protocol for selective gating of water and proton conduction across nanopores and temperature-controlled drug release.

Hydrologic behavior of a steep forested slope prone to shallow landsliding

NASA Astrophysics Data System (ADS)

Berti, Matteo; Simoni, Alessandro

2015-04-01

Over the past ten years, the frequency of debris flows in the Northern Apennines of Italy has significantly increased. Gravitational movements in the area are dominated by slow-moving landslides involving fine-grained soils and, to a lesser extent, by shallow slips in weathered arenaceous rocks. During the past 5 years, at least 20 debris flow events were triggered by exceptional rainfall events. Although no fatalities of injuries resulted from these landslides, the appearance of this new danger generated great concern among local communities. The Civil Protection Agency of the Emilia-Romagna region therefore decided to produce a debris flow susceptibility map to target high-risk zones and to help local authorities in emergency planning. This task, however, is particularly difficult due to the lack of historical data required to apply heuristic or statistical methods. In this context we installed a monitoring system on a representative slope in order to investigate the hydrologic response to rainfall and to support the choice of a suitable deterministic model. The selected slope is close to the village of Porretta Terme (Province of Bologna, Italy) at an elevation of 510 m asl. The slope has an inclination of about 30° and consists of a thin soil cover (0.5-1 thickness) lying over a fractured arenaceous bedrock. The soil is a well-graded sand with silt, gravel, cobbles, and weathered rock blocks. The slope is densely vegetated with grass, shrubs and mature trees. Part of the slope failed on the 30th November 2008 after a rainfall of 140 mm in 24 hours. A shallow slide of the soil mantle rapidly mobilized into debris flow leaving the bedrock exposed in the source area. The monitoring system is located on an unfailed slope close to the initiation area. The system consists of three stations aligned along the maximum slope at a distance of 15-20 m. Each station is equipped with: i) an open-standpipe piezometer installed near the soil-rock interface (1 m deep); ii) three tensiometers installed in the soil cover at different depths (0.2, 0.5 and 0.8 m); iii) three soil moisture capacitance sensors installed beside the tensiometer probes. The uphill station also includes an ultrasonic sensor for measuring snow depth and a barometric/temperature sensor. A tipping-bucket rain gage is installed in an area free of tree vegetation located 50 m further uphill. All the data are recorded every 10 minutes and stored on site. The monitoring system was installed in September 2012 and the first two years of data provide a consistent picture of slope hydrology. During all the dry season (from June to September) the sandy soil is essentially dry with strong negative pore pressures (less than -80 kPa). Occasional summer rainfall causes the infiltration of water into the unsaturated soil but the soil never approaches the saturation, nor groundwater is accumulated at the soil-rock interface. With the start of the wet season (around October) the soil water content progressively increases and the pore pressure rises to values detectable by the tensiometers (higher than 80 kPa). The soil, however, remains generally unsaturated with negative pore pressures in the order of -20/-30 kPa. Full saturation is temporarily reached in response to intense rainfall events. Rainfall water induce fast, transient pore pressure increases in the soil mantle and moves vertically toward the soil-rock interface, eventually leading to the development of a transient perched water table during the heaviest rainfall events. The thickness of the perched water table is clearly related to rainfall intensity (very intense rainfall may saturate up to 80% of the soil profile) while the contribution of lateral flow is less evident probably because it is dominated by macropores or because because bedrock fractures favour deeper circulation.

Membrane separation technology in the 1980s

NASA Technical Reports Server (NTRS)

Lonsdale, H. K.

1982-01-01

The current status of membrane technology is assessed and industrial processes in which membrane technology could effect energy savings or other advantages are identified. The extension of current trends is recommended; i.e., the development of ultrathin and highly permselective membranes, the use of specific carriers to enhance permselectivity and permit 'uphill' diffusion, and the improvement of separation efficiency. Membranes are predicted to be important in biotechnology and in the production of solar energy. Guidelines indicating where and how to look for opportunities where evolving membrane technology might fit are provided.

7. THE BEGINNING OF A PANORAMIC SERIES VIEW LOOKING WEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. THE BEGINNING OF A PANORAMIC SERIES VIEW LOOKING WEST NORTHWEST FROM THE UPHILL SIDE OF THE MILL. THE ORE RECEIVING HOUSE IS IN THE IMAGE CENTER, THE ORE DELIVERY TRESTLE EXTENDS FROM THE RECEIVING HOUSE TO THE MILL BUILDING IN THE BACKGROUND LEFT. IN THE MID-GROUND LEFT IS A CYLINDRICAL STRUCTURE BELIEVE TO BE A SETTLING TANK FROM A LATER CHEMICAL RETREATMENT OF THE TAILINGS IN THE FOREGROUND RIGHT IS AN EXTANT ORE BUCKET. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

Water and solute transport across the peritoneal membrane.

PubMed

Morelle, Johann; Devuyst, Olivier

2015-09-01

We review the molecular mechanisms of peritoneal transport and discuss how a better understanding of these mechanisms is relevant for dialysis therapy. Peritoneal dialysis involves diffusion and osmosis through the highly vascularized peritoneal membrane. Computer simulations, expression studies and functional analyses in Aqp1 knockout mice demonstrated the critical role of the water channel aquaporin-1 (AQP1) in water removal during peritoneal dialysis. Pharmacologic regulation of AQP1, either through increased expression or gating, is associated with increased water transport in rodent models of peritoneal dialysis. Water transport is impaired during acute peritonitis, despite unchanged expression of AQP1, resulting from the increased microvascular area that dissipates the osmotic gradient across the membrane. In long-term peritoneal dialysis patients, the fibrotic interstitium also impairs water transport, resulting in ultrafiltration failure. Recent data suggest that stroke and drug intoxications might benefit from peritoneal dialysis and could represent novel applications of peritoneal transport in the future. A better understanding of the regulation of osmotic water transport across the peritoneum offers novel insights into the role of water channels in microvascular endothelia, the functional importance of structural changes in the peritoneal interstitium and the transport of water and solutes across biological membranes in general.

Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit

PubMed Central

Zeuthen, T; Meinild, A-K; Loo, D D F; Wright, E M; Klaerke, D A

2001-01-01

In order to study its role in steady state water transport, the Na+-glucose cotransporter (SGLT1) was expressed in Xenopus laevis oocytes; both the human and the rabbit clones were tested. The transport activity was monitored as a clamp current and the flux of water followed optically as the change in oocyte volume. SGLT1 has two modes of water transport. First, it acts as a molecular water pump: for each 2 Na+ and 1 sugar molecule 264 water molecules were cotransported in the human SGLT1 (hSGLT1), 424 for the rabbit SGLT1 (rSGLT1). Second, it acts as a water channel. The cotransport of water was tightly coupled to the sugar-induced clamp current. Instantaneous changes in clamp current induced by changes in clamp voltage were accompanied by instantaneous changes in the rate of water transport. The cotransported solution was predicted to be hypertonic, and an osmotic gradient built up across the oocyte membrane with continued transport; this resulted in an additional osmotic influx of water. After 5-10 min a steady state was achieved in which the total influx was predicted to be isotonic with the intracellular solution. With the given expression levels, the steady state water transport was divided about equally between cotransport, osmosis across the SGLT1 and osmosis across the native oocyte membrane. Coexpression of AQP1 with the SGLT1 increased the water permeability more than 10-fold and steady state isotonic transport was achieved after less than 2 s of sugar activation. One-third of the water was cotransported, and the remainder was osmotically driven through the AQP1. The data suggest that SGLT1 has three roles in isotonic water transport: it cotransports water directly, it supplies a passive pathway for osmotic water transport, and it generates an osmotic driving force that can be employed by other pathways, for example aquaporins. PMID:11251046

41 CFR 302-10.5 - May I transport a mobile home over water?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false May I transport a mobile home over water? 302-10.5 Section 302-10.5 Public Contracts and Property Management Federal Travel... transport a mobile home over water? Yes, you may transport a mobile home over water when both the points of...

41 CFR 302-10.5 - May I transport a mobile home over water?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 4 2011-07-01 2011-07-01 false May I transport a mobile home over water? 302-10.5 Section 302-10.5 Public Contracts and Property Management Federal Travel... transport a mobile home over water? Yes, you may transport a mobile home over water when both the points of...

Habitat stability and occurrences of malaria vector larvae in western Kenya highlands.

PubMed

Himeidan, Yousif E; Zhou, Guofa; Yakob, Laith; Afrane, Yaw; Munga, Stephen; Atieli, Harrysone; El-Rayah, El-Amin; Githeko, Andrew K; Yan, Guiyun

2009-10-21

Although the occurrence of malaria vector larvae in the valleys of western Kenya highlands is well documented, knowledge of larval habitats in the uphill sites is lacking. Given that most inhabitants of the highlands actually dwell in the uphill regions, it is important to develop understanding of mosquito breeding habitat stability in these sites in order to determine their potential for larval control. A total of 128 potential larval habitats were identified in hilltops and along the seasonal streams in the Sigalagala area of Kakamega district, western Kenya. Water availability in the habitats was followed up daily from August 3, 2006 to February 23, 2007. A habitat is defined as stable when it remains aquatic continuously for at least 12 d. Mosquito larvae were observed weekly. Frequencies of aquatic, stable and larvae positive habitats were compared between the hilltop and seasonal stream area using chi2-test. Factors affecting the presence/absence of Anopheles gambiae larvae in the highlands were determined using multiple logistic regression analysis. Topography significantly affected habitat availability and stability. The occurrence of aquatic habitats in the hilltop was more sporadic than in the stream area. The percentage of habitat occurrences that were classified as stable during the rainy season is 48.76% and 80.79% respectively for the hilltop and stream area. Corresponding frequencies of larvae positive habitats were 0% in the hilltop and 5.91% in the stream area. After the rainy season, only 23.42% of habitat occurrences were stable and 0.01% larvae positive habitats were found in the hilltops, whereas 89.75% of occurrences remained stable in the stream area resulting in a frequency of 12.21% larvae positive habitats. The logistic regression analysis confirmed the association between habitat stability and larval occurrence and indicated that habitat surface area was negatively affecting the occurrence of An. gambiae larvae. While An. gambiae and An. funestus larvae occurred throughout the study period along the streams, a total of only 15 An. gambiae larvae were counted in the hilltops, and no An. funestus were found. Moreover, no larvae managed to develop into adults in the hilltops, and the density of adult An. gambiae was consistently low, averaging at 0.06 females per house per survey. The occurrence of malaria vector larvae in the hilltop area was uncommon as a result of the low availability and high instability of habitats. To optimize the cost-effectiveness of malaria interventions in the western Kenya highlands, larval control should be focused primarily along the streams, as these are likely the only productive habitats at high altitude.

Atmospheric River Importance to Extratropical Climate and Hydrology

NASA Astrophysics Data System (ADS)

Nash, D.; Waliser, D. E.; Guan, B.; Ye, H.; Ralph, F. M.

2017-12-01

Atmospheric Rivers (ARs) are narrow, long, water vapor rich corridors of the atmosphere that are responsible for over 90% of the poleward moisture transport across mid-latitudes and into high latitudes. This suggests a crucial role for ARs in helping establish the extra-tropical atmospheric water budget and hydroclimate variability. However, the contribution of ARs to the extra-tropical atmospheric water budget has yet to be quantified, including impacts on water vapor transport and storage, and precipitation. This study characterizes the roles of AR related atmospheric transport on combined and individual atmospheric water budget variables over extratropical regions of both hemispheres based on MERRA2 reanalysis products during 1997-2014. Results show that poleward water vapor transport related to ARs is strongly related to changes in water vapor storage and especially precipitation in higher latitudes in both hemispheres, with the relationship dependent on averaging period. For example, for the annual cycle climatology, both AR transport and local evaporation support the variation in precipitation. However, on monthly time scales, the water budget at higher latitudes tends to be dominated by the balance between AR transport and precipitation. On pentad and daily time scales, AR transport is related to both precipitation and water vapor storage changes. These results indicate the important role of the episodic, extreme moisture transports associated with ARs in helping establish the high latitude water and energy cycles, and associated hydroclimate.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

NASA Astrophysics Data System (ADS)

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Time and Space in Tzeltal: Is the Future Uphill?

PubMed Central

Brown, Penelope

2012-01-01

Linguistic expressions of time often draw on spatial language, which raises the question of whether cultural specificity in spatial language and cognition is reflected in thinking about time. In the Mayan language Tzeltal, spatial language relies heavily on an absolute frame of reference utilizing the overall slope of the land, distinguishing an “uphill/downhill” axis oriented from south to north, and an orthogonal “crossways” axis (sunrise-set) on the basis of which objects at all scales are located. Does this absolute system for calculating spatial relations carry over into construals of temporal relations? This question was explored in a study where Tzeltal consultants produced temporal expressions and performed two different non-linguistic temporal ordering tasks. The results show that at least five distinct schemata for conceptualizing time underlie Tzeltal linguistic expressions: (i) deictic ego-centered time, (ii) time as an ordered sequence (e.g., “first”/“later”), (iii) cyclic time (times of the day, seasons), (iv) time as spatial extension or location (e.g., “entering/exiting July”), and (v) a time vector extending uphillwards into the future. The non-linguistic task results showed that the “time moves uphillwards” metaphor, based on the absolute frame of reference prevalent in Tzeltal spatial language and thinking and important as well in the linguistic expressions for time, is not strongly reflected in responses on these tasks. It is argued that systematic and consistent use of spatial language in an absolute frame of reference does not necessarily transfer to consistent absolute time conceptualization in non-linguistic tasks; time appears to be more open to alternative construals. PMID:22787451

Effect of added mass on treadmill performance and pulmonary function.

PubMed

Walker, Rachel E; Swain, David P; Ringleb, Stacie I; Colberg, Sheri R

2015-04-01

Military personnel engage in strenuous physical activity and load carriage. This study evaluated the role of body mass and of added mass on aerobic performance (uphill treadmill exercise) and pulmonary function. Performance on a traditional unloaded run test (4.8 km) was compared with performance on loaded tasks. Subjects performed an outdoor 4.8-km run and 4 maximal treadmill tests wearing loads of 0, 10, 20, and 30 kg. Subjects' pulmonary function (forced expired volume in 1 second [FEV1], forced vital capacity [FVC], and maximal voluntary ventilation [MVV]) was tested with each load, and peak values of heart rate, oxygen consumption ((Equation is included in full-text article.)), ventilation (VE), and respiratory exchange ratio (RER) were measured during each treadmill test. Performance on the 4.8-km run was correlated with treadmill performance, measured as time to exhaustion (TTE), with the strength of the correlation decreasing with load (r = 0.87 for 0 kg to 0.76 for 30 kg). Body mass was not correlated with TTE, other than among men with the 30-kg load (r = 0.48). During treadmill exercise, all peak responses other than RER decreased with load. Pulmonary function measures (FEV1, FVC, and MVV) decreased with load. Body mass was poorly correlated with treadmill performance, but added mass decreased performance. The decreased performance may be in part because of decreased pulmonary function. Unloaded 4.8-km run performance was correlated to unloaded uphill treadmill performance, but less so as load increased. Therefore, traditional run tests may not be an effective means of evaluating aerobic performance for military field operations.

Influence of standing position on mechanical and energy costs in uphill cycling.

PubMed

Bouillod, Anthony; Pinot, Julien; Valade, Aurélien; Cassirame, Johan; Soto-Romero, Georges; Grappe, Frédéric

2018-04-27

This study was designed to examine the influence of standing position (vs. seated) during uphill cycling on both mechanical cost (MC) and energy cost (EC) in elite cyclists. For the study, thirteen elite cyclists (VO 2max : 71.4 ± 8.0 ml·min -1 ·kg -1 ) performed, in a randomised order, three sets of exercises. Each set comprised 2 min of exercise, alternating every 30 s between seated and standing postures, using different slopes and intensity levels on a motorised treadmill. MC was calculated from the measurement of power output and speed, whereas EC was calculated from the measurement of oxygen consumption and speed. MC was significantly higher (+4.3%, p < 0.001) in standing position compared to seated position when all slopes and intensities were considered. However, EC was not significantly affected by the change in position. The standing position also induced a significant increase in rolling resistance power (p < 0.001), rolling resistance coefficient (p < 0.001) and lateral sways (p < 0.001). The significant increase in MC observed in standing position was due to a higher rolling resistance induced by bicycle sways and a shift forward of the centre of mass compared to seated position. This result should lead bicycle tire manufacturers to reduce the increase in rolling resistance between the two positions. Considering the relationship observed between the MC and bicycle sways, cyclists would be well advised to decrease the bicycle sways in order to reduce the MC of locomotion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Overview of Models Used in Land Treatment of Wastewater

DTIC Science & Technology

1982-03-01

The limitation of the ratio of fecal califorms to total coliphage as a water pollution index. Water Resources, vol. 10, p. 745-748. Bouma, J. (1981...predicting.Ar water and salt transport in soils, 2)-nitrogen transport and transformations, 3) phosphorus transport and transformations, 4r-virus...1 Models for planning, site selection and cost analysis .......... 2 Models for predicting water and salt transport in soils

Different stages and status of vertical transporting process of Cu in Jiaozhou Bay

NASA Astrophysics Data System (ADS)

Yang, Dongfang; Li, Haixia; Wang, Qi; Zhang, Xiaolong; Ding, Jun

2017-12-01

Understanding the stages and status of vertical transporting process of pollutant in marine bay is essential to pollution control. This paper analyzed the stages and status of Cu’s vertical transporting process in waters in Jiaozhou Bay. Results showed that the vertical transporting process in waters in Jiaozhou Bay included four stages of 1) Cu was imported to the bay by major sources, 2) Cu was transported to surface waters, 3) Cu was transported from surface waters to sediment in sea bottom, and 4) Cu was fixed and buried in sediment. Furthermore, Cu’s vertical transporting process could be divided into seven status in detail, and he characteristics of the vertical transport process of Cu were also analyzed.

Effect of Provision of Feed and Water during Transport on the Welfare of Weaned Pigs

PubMed Central

Garcia, Arlene; Pirner, Glenna; Picinin, Guilherme; May, Matthew; Guay, Kimberly; Backus, Brittany; Sutherland, Mhairi; McGlone, John

2015-01-01

Simple Summary Transportation is a complex stressor, which has the potential to negatively impact the health and welfare of weaned pigs. Transport duration and withdrawal from feed and water are two factors that could potentially adversely affect the welfare of pigs transported at weaning. In this study, the effect of a 32 h transport period and the provision of feed and water on the welfare of weaned pigs was investigated using a multi-disciplinary approach. Body weight decreased in weaned pigs over time and this response was exacerbated by exposing pigs to a 32 h transport period and withdrawing feed and water. The greatest changes in body weight loss were observed after 8 h of transport or weaning. Furthermore, the neutrophil to lymphocyte ratio (N:L) stress measure was elevated in pigs in response to an 8 h transport period or 8 h after weaning alone. With the exception of weaned pigs provided with feed and water, transported and weaned pigs continued to be different from control pigs until 16 h after weaning or exposure to a 16 h transport period. These findings suggest that pigs experience an acute stress response due to transport and weaning, but these two stressors do not appear to be additive. Overall, transportation had a negative effect on performance, physiology and behavior of weaned and transported pigs, especially if not provided with feed and water for more than 24 h. Abstract Transportation is a complex stressor made up of factors including weaning itself and withdrawal from feed and water. Therefore, transportation has the potential to negatively impact the health and welfare of weaned pigs. Pigs were transported for 32 h and measures of performance, physiology, and behavior were taken to assess piglet welfare. Treatment groups included pigs not weaned or transported (CON), weaned pigs provided with feed and water (WEAN+), weaned pigs not provided with feed and water (WEAN−), weaned and transported pigs provided with feed and water (TRANS+), and weaned and transported pigs not provided with feed and water (TRANS−). Body weight loss was different among treatments (p < 0.01). CON pigs had a 6.5% ± 0.45% gain in body weight after 32 h. WEAN+, WEAN−, TRANS+, and TRANS− groups all had a loss in body weight of 5.9% ± 0.45%, 7.8% ± 0.45%, 6.5% ± 0.45% and 9.1% ± 0.46%, respectively. The N:L was greater in all weaned pigs at 8 h compared to CON pigs (p < 0.01). WEAN− and transported pigs had significantly higher N:L than CON pigs from 8 h through 16 h, however, all treatment groups were similar to CON pigs after 16 h irrespective of provision of feed and water. Blood glucose levels were lower in transported and/or weaned pigs than CON pigs after 16 h irrespective of the provision of feed and water. TRANS+ females had higher creatine kinase (CK) levels than males (p < 0.05). After a 16 h transport period, TRANS− pigs had higher total plasma protein (TP) levels than all other treatment groups (p < 0.05). Significant changes in behavior were observed during and after transportation, which could also be indicative of stress. Overall, transportation and weaning had a negative effect on performance, physiology and behavior (both during and post-weaning) of pigs, especially when feed and water was not provided. Transporting pigs without feed and water for more than 24 h was a welfare concern as indicated by changes in body weight and physiology measures of stress. PMID:26479242

49 CFR 230.55 - Tubular type water and lubricator glasses and shields.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Tubular type water and lubricator glasses and shields. 230.55 Section 230.55 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Water...

49 CFR 230.55 - Tubular type water and lubricator glasses and shields.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Tubular type water and lubricator glasses and shields. 230.55 Section 230.55 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Water...

49 CFR 230.55 - Tubular type water and lubricator glasses and shields.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Tubular type water and lubricator glasses and shields. 230.55 Section 230.55 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Water...

Composite Transport Model and Water and Solute Transport across Plant Roots: An Update.

PubMed

Kim, Yangmin X; Ranathunge, Kosala; Lee, Seulbi; Lee, Yejin; Lee, Deogbae; Sung, Jwakyung

2018-01-01

The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM). It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots - apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs), which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic). Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle). The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

Nano and Mesoscale Ion and Water Transport in Perfluorosulfonic AcidMembranes

DTIC Science & Technology

2017-10-01

Nano- and Mesoscale Ion and Water Transport in Perfluorosulfonic-Acid Membranes A. R. Crothers a,b , C. J. Radke a,b , A. Z. Weber a a...Berkeley, CA 94720, USA Water and aqueous cations transport along multiple length scales in perfluorosulfonic-acid membranes. Molecular interactions...as a function of hydration. A resistor network upscales the nanoscale properties to predict effective membrane ion and water transport and their

Can Free Water Transport Be Used as a Clinical Parameter for Peritoneal Fibrosis in Long-Term PD Patients?

PubMed Central

Krediet, Raymond T.; Barreto, Deirisa Lopes; Struijk, Dirk G.

2016-01-01

Sodium sieving in peritoneal dialysis (PD) occurs in a situation with high osmotically-driven ultrafiltration rates. This dilutional phenomenon is caused by free water transport through the water channel aquaporin-1. It has recently been described that encapsulating peritoneal fibrosis is associated with impaired free water transport, despite normal expression of aquaporin-1. In this review, it will be argued that free water transport can be used for assessment of fibrotic peritoneal alterations, due to the water-binding capacity of collagen. Finally, the consequences for clinical practice will be discussed. PMID:26475849

Mathematical model of water transport in Bacon and alkaline matrix-type hydrogen-oxygen fuel cells

NASA Technical Reports Server (NTRS)

Prokopius, P. R.; Easter, R. W.

1972-01-01

Based on general mass continuity and diffusive transport equations, a mathematical model was developed that simulates the transport of water in Bacon and alkaline-matrix fuel cells. The derived model was validated by using it to analytically reproduce various Bacon and matrix-cell experimental water transport transients.

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

Well-to-Wheels Water Consumption: Tracking the Virtual Flow of Water into Transportation

NASA Astrophysics Data System (ADS)

Lampert, D. J.; Elgowainy, A.; Hao, C.

2015-12-01

Water and energy resources are fundamental to life on Earth and essential for the production of consumer goods and services in the economy. Energy and water resources are heavily interdependent—energy production consumes water, while water treatment and distribution consume energy. One example of this so-called energy-water nexus is the consumption of water associated with the production of transportation fuels. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can be used to compare the environmental impacts of different transportation fuels on a consistent basis. In this presentation, the expansion of GREET to perform life cycle water accounting or the "virtual flow" of water into transportation and other energy sectors and the associated implications will be discussed. The results indicate that increased usage of alternative fuels may increase freshwater resource consumption. The increased water consumption must be weighed against the benefits of decreased greenhouse gas and fossil energy consumption. Our analysis highlights the importance of regionality, co-product allocation, and consistent system boundaries when comparing the water intensity of alternative transportation fuel production pathways such as ethanol, biodiesel, compressed natural gas, hydrogen, and electricity with conventional petroleum-based fuels such as diesel and gasoline.

Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei

PubMed Central

Nakamura, Itsumi; Meyer, Carl G.; Sato, Katsufumi

2015-01-01

We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei) in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200–300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200–300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes), indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath) or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats. PMID:26061525

Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei.

PubMed

Nakamura, Itsumi; Meyer, Carl G; Sato, Katsufumi

2015-01-01

We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei) in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200-300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200-300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes), indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath) or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats.

Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions.

PubMed

Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M

2015-09-01

Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of warming and associated soil drying on C assimilation across an entire growing season. Moisture and temperature limitations were each estimated to reduce potential growing season C gain from a theoretical upper limit by 15-30% (c. 50% combined). Warming above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Dancing drops over vibrating substrates

NASA Astrophysics Data System (ADS)

Borcia, Rodica; Borcia, Ion Dan; Helbig, Markus; Meier, Martin; Egbers, Christoph; Bestehorn, Michael

2017-04-01

We study the motion of a liquid drop on a solid plate simultaneously submitted to horizontal and vertical harmonic vibrations. The investigation is done via a phase field model earlier developed for describing static and dynamic contact angles. The density field is nearly constant in every bulk region (ρ = 1 in the liquid phase, ρ ≈ 0 in the vapor phase) and varies continuously from one phase to the other with a rapid but smooth variation across the interfaces. Complicated explicit boundary conditions along the interface are avoided and captured implicitly by gradient terms of ρ in the hydrodynamic basic equations. The contact angle θ is controlled through the density at the solid substrate ρ S , a free parameter varying between 0 and 1 [R. Borcia, I.D. Borcia, M. Bestehorn, Phys. Rev. E 78, 066307 (2008)]. We emphasize the swaying and the spreading modes, earlier theoretically identified by Benilov and Billingham via a shallow-water model for drops climbing uphill along an inclined plane oscillating vertically [E.S. Benilov, J. Billingham, J. Fluid Mech. 674, 93 (2011)]. The numerical phase field simulations will be completed by experiments. Some ways to prevent the release of the dancing drops along a hydrophobic surface into the gas atmosphere are also discussed in this paper.

2. View, structures in Systems Integration Laboratory complex, looking north. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. View, structures in Systems Integration Laboratory complex, looking north. The Components Test Laboratory (T-27) is located in the immediate foreground. Immediately uphill to the left of T-27 is the Boiler Chiller Plant (T-28H). To the left of T-28H is the Oxidizer Conditioning Structure (T-28D). Behind the T-28D is the Long-Term Oxidizer Silo (T-28B). The twin gantry structure at the left is the Systems Integration Laboratory (T-28). - Air Force Plant PJKS, Systems Integration Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Photocatalytic CO 2 Reduction by Trigonal-Bipyramidal Cobalt(II) Polypyridyl Complexes: The Nature of Cobalt(I) and Cobalt(0) Complexes upon Their Reactions with CO 2, CO, or Proton

DOE PAGES

Shimoda, Tomoe; Morishima, Takeshi; Kodama, Koichi; ...

2018-04-26

Trigonal-bipyramidal Co(II) complexes are used for photochemical carbon dioxide (CO 2) reduction with Ru(bpy) 3 2+ as a photosensitizer, tri-p-tolylamine (TTA) as a reversible quencher, and triethylamine (TEA) as a sacrificial electron donor to produce carbon monoxide and dihydrogen. Here, the CO 2 reduction is slow because of the large structural changes, spin flipping in the cobalt catalytic intermediates, and an uphill reaction for reduction to catalytically active Co(0) by the photoproduced [Ru(bpy) 3] +.

Physics of X-ray Multilayer Structures: Summaries of Papers Presented at the Physics of X-ray Multilayer Structures Topical Meeting Held in Jackson Hole, Wyoming on March 2-5, 1992. (1992 Technical Digest Series Volume 7).

DTIC Science & Technology

1992-03-01

Synchrotron Radiation Facility, France. A novel method for depositing large size multilayers is de - GRAND ROOM scribed. A plasma produced by distributed...explained by the uphill diffusion of metal Univ. Paris, France. The Born approximation is applied to de - atoms. (p. 27) scribe the diffractive properties of...D. G. TuAl Roughness evolution in films and multilayer struc- Steams, Lawrence Livermore National Laboratory. The de - tuns, M. G. Lagally, Univ

Photocatalytic CO 2 Reduction by Trigonal-Bipyramidal Cobalt(II) Polypyridyl Complexes: The Nature of Cobalt(I) and Cobalt(0) Complexes upon Their Reactions with CO 2, CO, or Proton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimoda, Tomoe; Morishima, Takeshi; Kodama, Koichi

Trigonal-bipyramidal Co(II) complexes are used for photochemical carbon dioxide (CO 2) reduction with Ru(bpy) 3 2+ as a photosensitizer, tri-p-tolylamine (TTA) as a reversible quencher, and triethylamine (TEA) as a sacrificial electron donor to produce carbon monoxide and dihydrogen. Here, the CO 2 reduction is slow because of the large structural changes, spin flipping in the cobalt catalytic intermediates, and an uphill reaction for reduction to catalytically active Co(0) by the photoproduced [Ru(bpy) 3] +.

DYNAMICS OF WATER TRANSPORT AND STORAGE IN CONIFERS STUDIED WITH DEUTERIUM AND HEAT TRACING TECHNIQUES

EPA Science Inventory

The volume and complexity of their vascular systems make the dynamics of long-distance water transport difficult to study. We used heat and deuterated water (D2O) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the co...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lampert, David J.; Cai, Hao; Wang, Zhichao

The production of all forms of energy consumes water. To meet increased energy demands, it is essential to quantify the amount of water consumed in the production of different forms of energy. By analyzing the water consumed in different technologies, it is possible to identify areas for improvement in water conservation and reduce water stress in energy-producing regions. The transportation sector is a major consumer of energy in the United States. Because of the relationships between water and energy, the sustainability of transportation is tied to management of water resources. Assessment of water consumption throughout the life cycle of amore » fuel is necessary to understand its water resource implications. To perform a comparative life cycle assessment of transportation fuels, it is necessary first to develop an inventory of the water consumed in each process in each production supply chain. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can used to estimate the full life-cycle environmental impacts of various transportation fuel pathways from wells to wheels. GREET is currently being expanded to include water consumption as a sustainability metric. The purpose of this report was to document data sources and methodologies to estimate water consumption factors (WCF) for the various transportation fuel pathways in GREET. WCFs reflect the quantity of freshwater directly consumed per unit production for various production processes in GREET. These factors do not include consumption of precipitation or low-quality water (e.g., seawater) and reflect only water that is consumed (i.e., not returned to the source from which it was withdrawn). The data in the report can be combined with GREET to compare the life cycle water consumption for different transportation fuels.« less

Influence of transport conditions and pre-slaughter water shower spray during summer on protein characteristics and water distribution of broiler breast meat.

PubMed

Xing, Tong; Li, Yun Han; Li, Ming; Jiang, Nan Nan; Xu, Xing Lian; Zhou, Guang Hong

2016-11-01

This study investigated the effects of pre-slaughter transport during summer and subsequent water shower spray on broiler meat quality and protein characteristics. Arbor Acres broiler chickens (n = 126, 42 days old, mixed sex, 2.5-3 kg) were randomly categorized into three treatments: (i) control group without transport (C); (ii) 30 min transport (T); and (iii) 30 min transport followed by 10 min water shower spray and 20 min lairage (T/W). Each treatment consisted of six replicates with seven birds each. Ambient temperature was 32-35°C during transportation. Results indicated that transport during high ambient temperature denatured myosin and sarcoplasmic proteins, led to decreased protein solubility and resulted in glycogen phosphorylase precipitated to the myofibrillar fraction. Furthermore, meat quality in the transport group showed a pale, soft and exudative (PSE)-like syndrome. Water shower spray during lairage after transport reduced the degree of protein denaturation and lessened the deterioration of meat quality. © 2016 Japanese Society of Animal Science.

Comparative study of transport processes of nitrogen, phosphorus, and herbicides to streams in five agricultural basins, USA

USGS Publications Warehouse

Domagalski, Joseph L.; Ator, S.; Coupe, R.; McCarthy, K.; Lampe, D.; Sandstrom, M.; Baker, N.

2008-01-01

Agricultural chemical transport to surface water and the linkage to other hydrological compartments, principally ground water, was investigated at five watersheds in semiarid to humid climatic settings. Chemical transport was affected by storm water runoff, soil drainage, irrigation, and how streams were linked to shallow ground water systems. Irrigation practices and timing of chemical use greatly affected nutrient and pesticide transport in the semiarid basins. Irrigation with imported water tended to increase ground water and chemical transport, whereas the use of locally pumped irrigation water may eliminate connections between streams and ground water, resulting in lower annual loads. Drainage pathways in humid environments are important because the loads may be transported in tile drains, or through varying combinations of ground water discharge, and overland flow. In most cases, overland flow contributed the greatest loads, but a significant portion of the annual load of nitrate and some pesticide degradates can be transported under base-flow conditions. The highest basin yields for nitrate were measured in a semiarid irrigated system that used imported water and in a stream dominated by tile drainage in a humid environment. Pesticide loads, as a percent of actual use (LAPU), showed the effects of climate and geohydrologic conditions. The LAPU values in the semiarid study basin in Washington were generally low because most of the load was transported in ground water discharge to the stream. When herbicides are applied during the rainy season in a semiarid setting, such as simazine in the California basin, LAPU values are similar to those in the Midwest basins. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

Treesearch

F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

2006-01-01

The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

9 CFR 3.63 - Food and water requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Food and water requirements. 3.63... Transportation of Rabbits Transportation Standards § 3.63 Food and water requirements. (a) If live rabbits are to be transported for a period of more than 6 hours, they shall have access to food and water or a type...

9 CFR 3.63 - Food and water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Food and water requirements. 3.63... Transportation of Rabbits Transportation Standards § 3.63 Food and water requirements. (a) If live rabbits are to be transported for a period of more than 6 hours, they shall have access to food and water or a type...

9 CFR 3.63 - Food and water requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Food and water requirements. 3.63... Transportation of Rabbits Transportation Standards § 3.63 Food and water requirements. (a) If live rabbits are to be transported for a period of more than 6 hours, they shall have access to food and water or a type...

9 CFR 3.63 - Food and water requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Food and water requirements. 3.63... Transportation of Rabbits Transportation Standards § 3.63 Food and water requirements. (a) If live rabbits are to be transported for a period of more than 6 hours, they shall have access to food and water or a type...

9 CFR 3.63 - Food and water requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Food and water requirements. 3.63... Transportation of Rabbits Transportation Standards § 3.63 Food and water requirements. (a) If live rabbits are to be transported for a period of more than 6 hours, they shall have access to food and water or a type...

Comparative assessment of water use and environmental implications of coal slurry pipelines

USGS Publications Warehouse

Palmer, Richard N.; James II, I. C.; Hirsch, R.M.

1977-01-01

With other studies conducted by the U.S. Geological Survey of water use in the conversion and transportation of the West 's coal, an analysis of water use and environmental implications of coal-slurry pipeline transport is presented. Simulations of a hypothetical slurry pipeline of 1000-mile length transporting 12.5 million tons per year indicate that pipeline costs and energy requirements are quite sensitive to the coal-to-water ratio. For realistic water prices, the optimal ratio will not vary far from the 50/50 ratio by weight. In comparison to other methods of energy conversion and transport, coal-slurry pipeline utilize about 1/3 the amount of water required for coal gasification, and about 1/5 the amount required for on-site electrical generation. An analysis of net energy output from operating alternative energy transportation systems for the assumed conditions indicates that both slurry pipeline and rail shipment require approximately 4.5 percent of the potential electrical energy output of the coal transported, and high-voltage, direct-current transportation requires approximately 6.5 percent. The environmental impacts of the different transports options are so substantially different that a common basis for comparison does not exist. (Woodard-USGS)

Visible light water splitting using dye-sensitized oxide semiconductors.

PubMed

Youngblood, W Justin; Lee, Seung-Hyun Anna; Maeda, Kazuhiko; Mallouk, Thomas E

2009-12-21

Researchers are intensively investigating photochemical water splitting as a means of converting solar to chemical energy in the form of fuels. Hydrogen is a key solar fuel because it can be used directly in combustion engines or fuel cells, or combined catalytically with CO(2) to make carbon containing fuels. Different approaches to solar water splitting include semiconductor particles as photocatalysts and photoelectrodes, molecular donor-acceptor systems linked to catalysts for hydrogen and oxygen evolution, and photovoltaic cells coupled directly or indirectly to electrocatalysts. Despite several decades of research, solar hydrogen generation is efficient only in systems that use expensive photovoltaic cells to power water electrolysis. Direct photocatalytic water splitting is a challenging problem because the reaction is thermodynamically uphill. Light absorption results in the formation of energetic charge-separated states in both molecular donor-acceptor systems and semiconductor particles. Unfortunately, energetically favorable charge recombination reactions tend to be much faster than the slow multielectron processes of water oxidation and reduction. Consequently, visible light water splitting has only recently been achieved in semiconductor-based photocatalytic systems and remains an inefficient process. This Account describes our approach to two problems in solar water splitting: the organization of molecules into assemblies that promote long-lived charge separation, and catalysis of the electrolysis reactions, in particular the four-electron oxidation of water. The building blocks of our artificial photosynthetic systems are wide band gap semiconductor particles, photosensitizer and electron relay molecules, and nanoparticle catalysts. We intercalate layered metal oxide semiconductors with metal nanoparticles. These intercalation compounds, when sensitized with [Ru(bpy)(3)](2+) derivatives, catalyze the photoproduction of hydrogen from sacrificial electron donors (EDTA(2-)) or non-sacrificial donors (I(-)). Through exfoliation of layered metal oxide semiconductors, we construct multilayer electron donor-acceptor thin films or sensitized colloids in which individual nanosheets mediate light-driven electron transfer reactions. When sensitizer molecules are "wired" to IrO(2).nH(2)O nanoparticles, a dye-sensitized TiO(2) electrode becomes the photoanode of a water-splitting photoelectrochemical cell. Although this system is an interesting proof-of-concept, the performance of these cells is still poor (approximately 1% quantum yield) and the dye photodegrades rapidly. We can understand the quantum efficiency and degradation in terms of competing kinetic pathways for water oxidation, back electron transfer, and decomposition of the oxidized dye molecules. Laser flash photolysis experiments allow us to measure these competing rates and, in principle, to improve the performance of the cell by changing the architecture of the electron transfer chain.

Suberized transport barriers in Arabidopsis, barley and rice roots: From the model plant to crop species.

PubMed

Kreszies, Tino; Schreiber, Lukas; Ranathunge, Kosala

2018-02-07

Water is the most important prerequisite for life and plays a major role during uptake and transport of nutrients. Roots are the plant organs that take up the major part of water, from the surrounding soil. Water uptake is related to the root system architecture, root growth, age and species dependent complex developmental changes in the anatomical structures. The latter is mainly attributed to the deposition of suberized barriers in certain layers of cell walls, such as endo- and exodermis. With respect to water permeability, changes in the suberization of roots are most relevant. Water transport or hydraulic conductivity of roots (Lp r ) can be described by the composite transport model and is known to be very variable between plant species and growth conditions and root developmental states. In this review, we summarize how anatomical structures and apoplastic barriers of roots can diversely affect water transport, comparing the model plant Arabidopsis with crop plants, such as barley and rice. Results comparing the suberin amounts and water transport properties indicate that the common assumption that suberin amount negatively correlates with water and solute transport through roots may not always be true. The composition, microstructure and localization of suberin may also have a great impact on the formation of efficient barriers to water and solutes. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

78 FR 71724 - Recordations, Water Carrier Tariffs, and Agricultural Contract Summaries

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-29

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board Recordations, Water Carrier Tariffs, and Agricultural Contract Summaries AGENCY: Surface Transportation Board, DOT. ACTION: Notice of OMB Approval of..., Control Number 2140-0025 (2) Water Carrier Tariffs, Control Number 2140-26 (3) Agricultural Contract...

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

NASA Astrophysics Data System (ADS)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-03-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

NASA Technical Reports Server (NTRS)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-01-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

Temperature influence on water transport in hardened cement pastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drouet, Emeline; Poyet, Stéphane, E-mail: stephane.poyet@cea.fr; Torrenti, Jean-Michel

2015-10-15

Describing water transport in concrete is an important issue for the durability assessment of radioactive waste management reinforced concrete structures. Due to the waste thermal output such structures would be submitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature on water transport within hardened cement pastes of four different formulations. Using a simplified approach (describing only the permeation of liquid water) we characterized the properties needed to describe water transport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presented and discussed.

Water transport across biological membranes: Overton, water channels, and peritoneal dialysis.

PubMed

Devuyst, O

2010-01-01

Peritoneal dialysis involves diffusive and convective transports and osmosis through the highly vascularized peritoneal membrane. Several lines of evidence have demonstrated that the water channel aquaporin-1 (AQP1) corresponds to the ultrasmall pore predicted by the modelization of peritoneal transport. Proof-of-principle studies have shown that upregulation of the expression of AQP1 in peritoneal capillaries is reflected by increased water permeability and ultrafiltration, without affecting the osmotic gradient and the permeability for small solutes. Inversely, studies in Aqp1 mice have shown that haplo-insufficiency in AQP1 is reflected by significant attenuation of water transport. Recent studies have identified lead compounds that could act as agonists of aquaporins, as well as putative binding sites and potential mechanisms of gating the water channel. By modulating water transport, these pharmacological agents could have clinically relevant effects in targeting specific tissues or disease states. These studies on the peritoneal membrane also provide an experimental framework to investigate the role of water channels in the endothelium and various cell types.

Generation of Combat Power by Insurgents: An Historical Analysis

DTIC Science & Technology

2013-06-13

the concept of operations. Transportation incorporates military, commercial, and multinational assets. Transportation includes motor , rail, air...and water modes. Transportation nodes include motor , rail, air, and water terminal operations. Transportation also includes movement control and

Water and heat transport in boreal soils: Implications for soil response to climate change

USGS Publications Warehouse

Fan, Z.; Neff, J.C.; Harden, J.W.; Zhang, T.; Veldhuis, H.; Czimczik, C.I.; Winston, G.C.; O'Donnell, J. A.

2011-01-01

Soil water content strongly affects permafrost dynamics by changing the soil thermal properties. However, the movement of liquid water, which plays an important role in the heat transport of temperate soils, has been under-represented in boreal studies. Two different heat transport models with and without convective heat transport were compared to measurements of soil temperatures in four boreal sites with different stand ages and drainage classes. Overall, soil temperatures during the growing season tended to be over-estimated by 2-4??C when movement of liquid water and water vapor was not represented in the model. The role of heat transport in water has broad implications for site responses to warming and suggests reduced vulnerability of permafrost to thaw at drier sites. This result is consistent with field observations of faster thaw in response to warming in wet sites compared to drier sites over the past 30. years in Canadian boreal forests. These results highlight that representation of water flow in heat transport models is important to simulate future soil thermal or permafrost dynamics under a changing climate. ?? 2011 Elsevier B.V.

Water and heat transport in boreal soils: Implications for soil response to climate change

USGS Publications Warehouse

Fan, Zhaosheng; Harden, Jennifer W.; Winston, G.C.; O'Donnell, Jonathan A.; Neff, Jason C.; Zhang, Tingjun; Veldhuis, Hugo; Czimczik, C.I.

2011-01-01

Soil water content strongly affects permafrost dynamics by changing the soil thermal properties. However, the movement of liquid water, which plays an important role in the heat transport of temperate soils, has been under-represented in boreal studies. Two different heat transport models with and without convective heat transport were compared to measurements of soil temperatures in four boreal sites with different stand ages and drainage classes. Overall, soil temperatures during the growing season tended to be over-estimated by 2–4 °C when movement of liquid water and water vapor was not represented in the model. The role of heat transport in water has broad implications for site responses to warming and suggests reduced vulnerability of permafrost to thaw at drier sites. This result is consistent with field observations of faster thaw in response to warming in wet sites compared to drier sites over the past 30 years in Canadian boreal forests. These results highlight that representation of water flow in heat transport models is important to simulate future soil thermal or permafrost dynamics under a changing climate.

Design of Nano Screw Pump for Water Transport and its Mechanisms

PubMed Central

Wang, LiYa; Wu, HengAn; Wang, FengChao

2017-01-01

Nanopumps conducting fluids through nanochannels have attracted considerable interest for their potential applications in nanofiltration, water desalination and drug delivery. Here, we demonstrate by molecular dynamics (MD) simulations that a nano screw pump is designed with helical nanowires embedded in a nanochannel, which can be used to drive unidirectional water flow. Such helical nanowires have been successfully synthesized in many experiments. By investigating the water transport mechanism through nano screw pumps with different configuration parameters, three transport modes were observed: cluster-by-cluster, pseudo-continuous, and linear-continuous, in which the water flux increases linearly with the rotating speed. The influences of the nanowires’ surface energy and the screw’s diameter on water transport were also investigated. Results showed that the water flux rate increases as the decreasing wettability of helical nanowires. The deviation in water flux in screw pumps with smaller radius is attributed to the weak hydrogen bonding due to space confinement and the hydrophobic blade. Moreover, we also proposed that such screw pumps with appropriate diameter and screw pitch can be used for water desalination. The study provides an insight into the design of multifunctional nanodevices for not only water transport but water desalination in practical applications. PMID:28155898

Lagrangian study of transport of subarctic water across the Subpolar Front in the Japan Sea

NASA Astrophysics Data System (ADS)

Prants, Sergey V.; Uleysky, Michael Yu.; Budyansky, Maxim V.

2018-06-01

The southward near-surface transport of transformed subarctic water across the Subpolar Front in the Japan Sea is simulated and analyzed based on altimeter data from January 1, 1993 to December 31, 2017. Computing Lagrangian indicators for a large number of synthetic particles, advected by the AVISO velocity field, we find preferred transport pathways across the Subpolar Front. The southward transport occurs mainly in the central part of the frontal zone due to suitable dispositions of mesoscale eddies promoting propagation of subarctic water to the south. It is documented with the help of Lagrangian origin and L-maps and verified by the tracks of available drifters. The transport of transformed subarctic water to the south is compared with the transport of transformed subtropical water to the north simulated by Prants et al. (Nonlinear Process Geophys 24(1):89-99, 2017c).

Lagrangian study of transport of subarctic water across the Subpolar Front in the Japan Sea

NASA Astrophysics Data System (ADS)

Prants, Sergey V.; Uleysky, Michael Yu.; Budyansky, Maxim V.

2018-05-01

The southward near-surface transport of transformed subarctic water across the Subpolar Front in the Japan Sea is simulated and analyzed based on altimeter data from January 1, 1993 to December 31, 2017. Computing Lagrangian indicators for a large number of synthetic particles, advected by the AVISO velocity field, we find preferred transport pathways across the Subpolar Front. The southward transport occurs mainly in the central part of the frontal zone due to suitable dispositions of mesoscale eddies promoting propagation of subarctic water to the south. It is documented with the help of Lagrangian origin and L-maps and verified by the tracks of available drifters. The transport of transformed subarctic water to the south is compared with the transport of transformed subtropical water to the north simulated by Prants et al. (Nonlinear Process Geophys 24(1):89-99, 2017c).

Moving Uphill: Microbial Facilitation at the Leading Edge of Plant Species Distributional Shifts

NASA Astrophysics Data System (ADS)

Suding, K.; Farrer, E.; Spasojevic, M.; Porazinska, D.; Bueno de Mesquita, C.; Schmidt, S. K.

2016-12-01

Climate change is expected to influence species distributions and reshuffle patterns of biodiversity. A key challenge to our understanding of these effects is that biotic interactions - new species to compete with, new stressors that increase dependence on facilitation, new prey or predators - will likely affect the ability of species to track climate at the leading edges of their distributional range. While it is well established that soil biota strongly influence plant abundance and diversity, it has been difficult to quantify the key belowground dynamics. This presentation will investigate the influence of one key biotic interaction, between plants and soil microbiota, on the ability of plant species to track climate change and expand their range uphill in a high montane system in the Front Range of Colorado. High-resolution photography from 1972 and 2008 indicate colonization of tundra vegetation in formerly unvegetated areas. Observational work on the distributions patterns of both plants and soil microbiota (bacteria, fungi and nematodes) in a spatially-explicit grid at the upper edge of plant distributions indicate strong, mostly positive, associations between plant species and soil taxa. Abiotic factors, while important, consistently underpredicted the occurrence of plant species and, in nine of the 12 most common tundra plants, co-occurring microbial taxa were important predictors of plant occurrence. Comparison of plant and microbial distributional patterns in 2007 and 2015 indicate the influence of microbial community composition on assembly and beta-diversity of the plant community over time. Plant colonization patterns in this region previously devoid of vegetation will likely influence carbon, nitrogen and phosphorus dynamics, with downstream consequences on nutrient limitation and phytoplankton composition in alpine lakes.

Uphill walking: Biomechanical demand on the lower extremities of obese adolescents.

PubMed

Strutzenberger, Gerda; Alexander, Nathalie; Bamboschek, Dominik; Claas, Elisabeth; Langhof, Helmut; Schwameder, Hermann

2017-05-01

The number of obesity prevalence in adolescents is still increasing. Obesity treatment programs typically include physical activity with walking being recommended as appropriate activity, but limited information exists on the demand uphill walking places on the joint loading and power of obese adolescents. Therefore, the purpose of this study was to investigate the effect of different inclinations on step characteristics, sagittal and frontal joint angles, joint moments and joint power of obese adolescents in comparison to their normal-weight peers. Eleven obese (14.5±1.41 years, BMI: 31.1±3.5kg/m 2 ) and eleven normal-weight adolescents (14.3±1.86 years, BMI: 19.0±1.7kg/m 2 ) walked with 1.11m/s on a ramp with two imbedded force plates (AMTI, 1000Hz) at three inclinations (level, 6°, 12°). Kinematic data were collected via an infrared-camera motion system (Vicon, 250Hz). The two-way (inclination, group) ANOVA indicated a significant effect of inclination on almost all variables analysed, with the hip joint being the most affected by inclination, followed by the knee and ankle joint. The obese participants additionally spent less time in swing phase, walked with an increased knee flexion and valgus angle and an increased peak hip flexion and adduction moment. Hip joint power of obese adolescents was especially in the steepest inclination significantly increased compared to their normal-weight peers. Obese adolescents demonstrate increased joint loading compared to their normal-weight peers and in combination with a musculoskeletal malalignment they might be prone to an increased overuse injury risk. Copyright © 2017 Elsevier B.V. All rights reserved.

Uphill energy transfer in photosystem I from Chlamydomonas reinhardtii. Time-resolved fluorescence measurements at 77 K.

PubMed

Giera, Wojciech; Szewczyk, Sebastian; McConnell, Michael D; Redding, Kevin E; van Grondelle, Rienk; Gibasiewicz, Krzysztof

2018-04-04

Energetic properties of chlorophylls in photosynthetic complexes are strongly modulated by their interaction with the protein matrix and by inter-pigment coupling. This spectral tuning is especially striking in photosystem I (PSI) complexes that contain low-energy chlorophylls emitting above 700 nm. Such low-energy chlorophylls have been observed in cyanobacterial PSI, algal and plant PSI-LHCI complexes, and individual light-harvesting complex I (LHCI) proteins. However, there has been no direct evidence of their presence in algal PSI core complexes lacking LHCI. In order to determine the lowest-energy states of chlorophylls and their dynamics in algal PSI antenna systems, we performed time-resolved fluorescence measurements at 77 K for PSI core and PSI-LHCI complexes isolated from the green alga Chlamydomonas reinhardtii. The pool of low-energy chlorophylls observed in PSI cores is generally smaller and less red-shifted than that observed in PSI-LHCI complexes. Excitation energy equilibration between bulk and low-energy chlorophylls in the PSI-LHCI complexes at 77 K leads to population of excited states that are less red-shifted (by ~ 12 nm) than at room temperature. On the other hand, analysis of the detection wavelength dependence of the effective trapping time of bulk excitations in the PSI core at 77 K provided evidence for an energy threshold at ~ 675 nm, above which trapping slows down. Based on these observations, we postulate that excitation energy transfer from bulk to low-energy chlorophylls and from bulk to reaction center chlorophylls are thermally activated uphill processes that likely occur via higher excitonic states of energy accepting chlorophylls.

A study of the 1963 Vajont landslide zonation by means of Lagrangian block modelling

NASA Astrophysics Data System (ADS)

Zaniboni, Filippo; Ausilia Paparo, Maria; Tinti, Stefano

2017-04-01

The 1963 landslide detaching from Mt. Toc (North-East Italy), that crashing on the underlying Vajont reservoir caused a huge wave that killed over 2000 people, is a well-known event that has been extensively and deeply investigated. Recently, studies appeared in the literature suggesting that the landslide dynamics can be explained in terms of a zonation of the moving mass. In this work, an additional support to the zonation hypothesis is given by focusing on the friction coefficient of the sliding surface, which is one of the chief parameters influencing the slide motion. Numerical simulations of the Vajont slide found in the literature assumed a homogenous value of the friction coefficient. We have systematically investigated a set of heterogeneous configurations. More specifically, we have divided the sliding surface into a number N of zones, and let the corresponding friction coefficient vary in the range 0-0.5. For each configuration we have run the numerical simulation via the Lagrangian block-based code UBO-BLOCK2 and have evaluated the configuration goodness by computing the misfit between the observed and the simulated deposits. The number of simulations required by this approach increases exponentially with the number N of zones. The main finding of this research is that a 4-sector zonation provides the best results in terms of deposit misfit. The zones can be roughly described as west-downhill (WD), west uphill (WU), east downhill (ED) and east uphill (EU). It is found that motion is mainly determined by friction in zones WD and EU, that friction coefficients in zone WD is remarkably smaller than in zone EU and that misfit is rather insensitive to the values of the friction coefficients in zones WU and ED.

The effect of uphill and downhill walking on gait parameters: A self-paced treadmill study.

PubMed

Kimel-Naor, Shani; Gottlieb, Amihai; Plotnik, Meir

2017-07-26

It has been shown that gait parameters vary systematically with the slope of the surface when walking uphill (UH) or downhill (DH) (Andriacchi et al., 1977; Crowe et al., 1996; Kawamura et al., 1991; Kirtley et al., 1985; McIntosh et al., 2006; Sun et al., 1996). However, gait trials performed on inclined surfaces have been subject to certain technical limitations including using fixed speed treadmills (TMs) or, alternatively, sampling only a few gait cycles on inclined ramps. Further, prior work has not analyzed upper body kinematics. This study aims to investigate effects of slope on gait parameters using a self-paced TM (SPTM) which facilitates more natural walking, including measuring upper body kinematics and gait coordination parameters. Gait of 11 young healthy participants was sampled during walking in steady state speed. Measurements were made at slopes of +10°, 0° and -10°. Force plates and a motion capture system were used to reconstruct twenty spatiotemporal gait parameters. For validation, previously described parameters were compared with the literature, and novel parameters measuring upper body kinematics and bilateral gait coordination were also analyzed. Results showed that most lower and upper body gait parameters were affected by walking slope angle. Specifically, UH walking had a higher impact on gait kinematics than DH walking. However, gait coordination parameters were not affected by walking slope, suggesting that gait asymmetry, left-right coordination and gait variability are robust characteristics of walking. The findings of the study are discussed in reference to a potential combined effect of slope and gait speed. Follow-up studies are needed to explore the relative effects of each of these factors. Copyright © 2017. Published by Elsevier Ltd.

Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere-fire numerical model

NASA Astrophysics Data System (ADS)

Simpson, C. C.; Sharples, J. J.; Evans, J. P.

2014-05-01

Fire channelling is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep lee-facing slope in a direction transverse to the background winds, and is often accompanied by a downwind extension of the active flaming region and extreme pyro-convection. Recent work using the WRF-Fire coupled atmosphere-fire model has demonstrated that fire channelling can be characterised as vorticity-driven lateral fire spread (VDLS). In this study, 16 simulations are conducted using WRF-Fire to examine the sensitivity of resolving VDLS to spatial resolution and atmosphere-fire coupling within the WRF-Fire model framework. The horizontal grid spacing is varied between 25 and 90 m, and the two-way atmosphere-fire coupling is either enabled or disabled. At high spatial resolution, the atmosphere-fire coupling increases the peak uphill and lateral spread rate by a factor of up to 2.7 and 9.5. The enhancement of the uphill and lateral spread rate diminishes at coarser spatial resolution, and VDLS is not modelled for a horizontal grid spacing of 90 m. The laterally spreading fire fronts become the dominant contributors of the extreme pyro-convection. The resolved fire-induced vortices responsible for driving the lateral spread in the coupled simulations have non-zero vorticity along each unit vector direction, and develop due to an interaction between the background winds and vertical return circulations generated at the flank of the fire front as part of the pyro-convective updraft. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere-fire coupling are required to reproduce VDLS within the current WRF-Fire model framework.

Transference of 3D accelerations during cross country mountain biking.

PubMed

Macdermid, Paul W; Fink, Philip W; Stannard, Stephen R

2014-06-03

Investigations into the work demands of Olympic format cross country mountain biking suggest an incongruent relationship between work done and physiological strain experienced by participants. A likely but unsubstantiated cause is the extra work demand of muscle damping of terrain/surface induced vibrations. The purpose of this study was to describe the relationship between vibration mechanics and their interaction with terrain, bicycle and rider during a race pace effort on a cross country mountain bike track, on both 26″ and 29″ wheels. Participants completed one lap of a cross country track using 26″ and 29″ wheels, at race pace. Power, cadence, speed, heart rate and geographical position were sampled and logged every second for control purposes. Tri-axial accelerometers located on the bicycle and rider, recorded accelerations (128Hz) and were used to quantify vibrations experienced during the whole lap and over terrain sections (uphill and downhill). While there were no differences in power output (p=0.3062) and heart rate (p=0.8423), time to complete the lap was significantly (p=0.0061) faster on the 29″ wheels despite increased vibrations in the larger wheels (p=0.0020). Overall accelerometer data (RMS) showed location differences (p<0.0001), specifically between the point of interface of bike-body compared to those experienced at the lower back and head. The reduction in accelerations at both the lower back and head are imperative for injury prevention and demonstrates an additional non-propulsive, muscular, challenge to riding. Stress was greatest during downhill sections as acceleration differences between locations were greater when compared to uphill sections, and thus possibly prevent the recovery processes that may occur during non-propulsive load. Copyright © 2014 Elsevier Ltd. All rights reserved.

Water footprint of U.S. transportation fuels.

PubMed

Scown, Corinne D; Horvath, Arpad; McKone, Thomas E

2011-04-01

In the modern global economy, water and energy are fundamentally connected. Water already plays a major role in electricity generation and, with biofuels and electricity poised to gain a significant share of the transportation fuel market, water will become significantly more important for transportation energy as well. This research provides insight into the potential changes in water use resulting from increased biofuel or electricity production for transportation energy, as well as the greenhouse gas and freshwater implications. It is shown that when characterizing the water impact of transportation energy, incorporating indirect water use and defensible allocation techniques have a major impact on the final results, with anywhere between an 82% increase and a 250% decrease in the water footprint if evaporative losses from hydroelectric power are excluded. The greenhouse gas impact results indicate that placing cellulosic biorefineries in areas where water must be supplied using alternative means, such as desalination, wastewater recycling, or importation can increase the fuel's total greenhouse gas footprint by up to 47%. The results also show that the production of ethanol and petroleum fuels burden already overpumped aquifers, whereas electricity production is far less dependent on groundwater.

Risk assessment of pesticide transport with water erosion: A conceptual model

NASA Astrophysics Data System (ADS)

Yang, Xiaomei; Van Der Zee, Sjoerd E. A. T. M.; Gai, Lingtong; Wesseling, Jan G.; Ritsema, Coen J.; Geissen, Violette

2017-04-01

Pesticides are widely used in agriculture, horticulture, and forestry, and pesticide pollution has become an important issue worldwide. Entraining in runoff and being attached to eroded soil particles, posing a risk to water and soil quality and human health. In order to assess the risk of pesticide during water erosion processes, a simple integrative model of pesticide transport by runoff and erosion was developed. Taking soil hydrological and pesticide behaviour into account, such as water infiltration, erosion, runoff, and pesticide transport and degradation in soil, the conceptual framework was based on the known assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. A sensitivity analysis was conducted and the results indicated that the total amount of pesticide related to soil eroded by water washing increased with slope gradient, rainfall intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became obviously and the time from pesticide sprayed to erosion occurring associated with pesticide degradation negatively influenced the total amount of transported pesticide. The mechanisms involved in pesticide transport, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, thus can be well accounted for pesticide risk assessment especially in the region with intensive pesticide use and soil water erosion events.

Evaluation of factors that influence estimated zones of transport for six municipal wells in Clark County, Washington

USGS Publications Warehouse

Orzol, L.L.; Truini, Margot

1999-01-01

Sensitivity of the zones of transport to change in the discharge rate of the selected well, porosity, and hydraulic conductivity, as well as to the presence or absence of interfering wells, was evaluated at six well sites to evaluate the effect of uncertainties in these factors on the size and shape of zones of transport. Uncertainty in porosity contributed the most to the uncertainty in delineating the zones of transport. Uncertainty in other factors, such as well discharge rate and horizontal hydraulic conductivity, had measurable effects on the zones of transport, but errors introduced through these factors were less significant. Insight into the causes of the changes in the size and shape of the zones of transport to varying conditions was gained by evaluating the simulated water budget and ground-water levels in the vicinity of the well. Changes in the simulated water budget and ground-water levels provided information to better understand the effects of uncertainties in the data on simulation results.The results of this study suggest that ground-water velocity is the underlying control on the size of the zones of transport. The regional hydraulic gradient is the most significant factor controlling the shape and orientation of the zones of transport. Spatial variation in recharge, discharge, and hydraulic properties can also affect the shape of the zones of transport, however. Underestimation of porosity or overestimation of horizontal hydraulic conductivity leads to overestimation of ground-water velocity and overestimation of the size of zones of transport. Overestimation of porosity or underestimation of horizontal hydraulic conductivity leads to underestimation of ground-water velocity and underestimation of the size of zones of transport. Well discharge rate affects ground-water velocities near the well. Underestimation of discharge (and therefore velocities) will result in underestimation of the size of the zones of transport. The sensitivity of estimated zones of transport to uncertainty in parameters such as porosity and horizontal hydraulic conductivity is a function of the well discharge rate and the proximity of the well to boundaries, such as streams and rivers.

Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: Moloch horridus)

NASA Astrophysics Data System (ADS)

Comanns, Philipp; Esser, Falk J.; Kappel, Peter H.; Baumgartner, Werner; Shaw, Jeremy; Withers, Philip C.

2017-09-01

Moisture-harvesting lizards, such as the Australian thorny devil Moloch horridus, have remarkable adaptations for inhabiting arid regions. Their microstructured skin surface, with channels in between overlapping scales, enables them to collect water by capillarity and passively transport it to the mouth for ingestion. We characterized this capillary water transport for live thorny devils using high-speed video analyses. Comparison with preserved specimens showed that live lizards are required for detailed studies of skin water transport. For thorny devils, there was no directionality in cutaneous water transport (unlike Phrynosoma) as 7 µl water droplets applied to the skin were transported radially over more than 9.2 mm. We calculated the total capillary volume as 5.76 µl cm-2 (dorsal) and 4.45 µl cm-2 (ventral), which is reduced to 50% filling by the time transportation ceases. Using micro-computed tomography and scanning electron microscopy of shed skin to investigate capillary morphology, we found that the channels are hierarchically structured as a large channel between the scales that is sub-divided by protrusions into smaller sub-capillaries. The large channel quickly absorbs water whereas the sub-capillary structure extends the transport distance by about 39% and potentially reduces the water volume required for drinking. An adapted dynamics function, which closely reflects the channel morphology, includes that ecological role.

Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: Moloch horridus).

PubMed

Comanns, Philipp; Esser, Falk J; Kappel, Peter H; Baumgartner, Werner; Shaw, Jeremy; Withers, Philip C

2017-09-01

Moisture-harvesting lizards, such as the Australian thorny devil Moloch horridus , have remarkable adaptations for inhabiting arid regions. Their microstructured skin surface, with channels in between overlapping scales, enables them to collect water by capillarity and passively transport it to the mouth for ingestion. We characterized this capillary water transport for live thorny devils using high-speed video analyses. Comparison with preserved specimens showed that live lizards are required for detailed studies of skin water transport. For thorny devils, there was no directionality in cutaneous water transport (unlike Phrynosoma ) as 7 µl water droplets applied to the skin were transported radially over more than 9.2 mm. We calculated the total capillary volume as 5.76 µl cm -2 (dorsal) and 4.45 µl cm -2 (ventral), which is reduced to 50% filling by the time transportation ceases. Using micro-computed tomography and scanning electron microscopy of shed skin to investigate capillary morphology, we found that the channels are hierarchically structured as a large channel between the scales that is sub-divided by protrusions into smaller sub-capillaries. The large channel quickly absorbs water whereas the sub-capillary structure extends the transport distance by about 39% and potentially reduces the water volume required for drinking. An adapted dynamics function, which closely reflects the channel morphology, includes that ecological role.

Water induced sediment levitation enhances downslope transport on Mars.

PubMed

Raack, Jan; Conway, Susan J; Herny, Clémence; Balme, Matthew R; Carpy, Sabrina; Patel, Manish R

2017-10-27

On Mars, locally warm surface temperatures (~293 K) occur, leading to the possibility of (transient) liquid water on the surface. However, water exposed to the martian atmosphere will boil, and the sediment transport capacity of such unstable water is not well understood. Here, we present laboratory studies of a newly recognized transport mechanism: "levitation" of saturated sediment bodies on a cushion of vapor released by boiling. Sediment transport where this mechanism is active is about nine times greater than without this effect, reducing the amount of water required to transport comparable sediment volumes by nearly an order of magnitude. Our calculations show that the effect of levitation could persist up to ~48 times longer under reduced martian gravity. Sediment levitation must therefore be considered when evaluating the formation of recent and present-day martian mass wasting features, as much less water may be required to form such features than previously thought.

Theoretical monochromatic-wave-induced currents in intermediate water with viscosity and nonzero mass transport

NASA Technical Reports Server (NTRS)

Talay, T. A.

1975-01-01

Wave-induced mass-transport current theories with both zero and nonzero net mass (or volume) transport of the water column are reviewed. A relationship based on the Longuet-Higgens theory is derived for wave-induced, nonzero mass-transport currents in intermediate water depths for a viscous fluid. The relationship is in a form useful for experimental applications; therefore, some design criteria for experimental wave-tank tests are also presented. Sample parametric cases for typical wave-tank conditions and a typical ocean swell were assessed by using the relation in conjunction with an equation developed by Unluata and Mei for the maximum wave-induced volume transport. Calculations indicate that substantial changes in the wave-induced mass-transport current profiles may exist dependent upon the assumed net volume transport. A maximum volume transport, corresponding to an infinite channel or idealized ocean condition, produces the largest wave-induced mass-transport currents. These calculations suggest that wave-induced mass-transport currents may have considerable effects on pollution and suspended-sediments transport as well as buoy drift, the surface and midlayer water-column currents caused by waves increasing with increasing net volume transports. Some of these effects are discussed.

75 FR 8412 - Office of New Reactors: Interim Staff Guidance on Assessing Ground Water Flow and Transport of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... NUCLEAR REGULATORY COMMISSION [NRC-2010-0047] Office of New Reactors: Interim Staff Guidance on Assessing Ground Water Flow and Transport of Accidental Radionuclide Releases; Solicitation of Public... ground water flow and transport of accidental radionuclide releases necessary to demonstrate compliance...

Abscisic acid accumulation modulates auxin transport in the root tip to enhance proton secretion for maintaining root growth under moderate water stress.

PubMed

Xu, Weifeng; Jia, Liguo; Shi, Weiming; Liang, Jiansheng; Zhou, Feng; Li, Qianfeng; Zhang, Jianhua

2013-01-01

Maintenance of root growth is essential for plant adaptation to soil drying. Here, we tested the hypothesis that auxin transport is involved in mediating ABA's modulation by activating proton secretion in the root tip to maintain root growth under moderate water stress. Rice and Arabidopsis plants were raised under a hydroponic system and subjected to moderate water stress (-0.47 MPa) with polyethylene glycol (PEG). ABA accumulation, auxin transport and plasma membrane H(+)-ATPase activity at the root tip were monitored in addition to the primary root elongation and root hair density. We found that moderate water stress increases ABA accumulation and auxin transport in the root apex. Additionally, ABA modulation is involved in the regulation of auxin transport in the root tip. The transported auxin activates the plasma membrane H(+)-ATPase to release more protons along the root tip in its adaption to moderate water stress. The proton secretion in the root tip is essential in maintaining or promoting primary root elongation and root hair development under moderate water stress. These results suggest that ABA accumulation modulates auxin transport in the root tip, which enhances proton secretion for maintaining root growth under moderate water stress. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Prediction of water loss and viscoelastic deformation of apple tissue using a multiscale model.

PubMed

Aregawi, Wondwosen A; Abera, Metadel K; Fanta, Solomon W; Verboven, Pieter; Nicolai, Bart

2014-11-19

A two-dimensional multiscale water transport and mechanical model was developed to predict the water loss and deformation of apple tissue (Malus × domestica Borkh. cv. 'Jonagold') during dehydration. At the macroscopic level, a continuum approach was used to construct a coupled water transport and mechanical model. Water transport in the tissue was simulated using a phenomenological approach using Fick's second law of diffusion. Mechanical deformation due to shrinkage was based on a structural mechanics model consisting of two parts: Yeoh strain energy functions to account for non-linearity and Maxwell's rheological model of visco-elasticity. Apparent parameters of the macroscale model were computed from a microscale model. The latter accounted for water exchange between different microscopic structures of the tissue (intercellular space, the cell wall network and cytoplasm) using transport laws with the water potential as the driving force for water exchange between different compartments of tissue. The microscale deformation mechanics were computed using a model where the cells were represented as a closed thin walled structure. The predicted apparent water transport properties of apple cortex tissue from the microscale model showed good agreement with the experimentally measured values. Deviations between calculated and measured mechanical properties of apple tissue were observed at strains larger than 3%, and were attributed to differences in water transport behavior between the experimental compression tests and the simulated dehydration-deformation behavior. Tissue dehydration and deformation in the high relative humidity range ( > 97% RH) could, however, be accurately predicted by the multiscale model. The multiscale model helped to understand the dynamics of the dehydration process and the importance of the different microstructural compartments (intercellular space, cell wall, membrane and cytoplasm) for water transport and mechanical deformation.

Water transport and energy.

PubMed

Fricke, Wieland

2017-06-01

Water transport in plants occurs along various paths and is driven by gradients in its free energy. It is generally considered that the mode of transport, being either diffusion or bulk flow, is a passive process, although energy may be required to sustain the forces driving water flow. This review aims at putting water flow at the various organisational levels (cell, organ, plant) in the context of the energy that is required to maintain these flows. In addition, the question is addressed (1) whether water can be transported against a difference in its chemical free energy, 'water potential' (Ψ), through, directly or indirectly, active processes; and (2) whether the energy released when water is flowing down a gradient in its energy, for example during day-time transpiration and cell expansive growth, is significant compared to the energy budget of plant and cell. The overall aim of review is not so much to provide a definite 'Yes' and 'No' to these questions, but rather to stimulate discussion and raise awareness that water transport in plants has its real, associated, energy costs and potential energy gains. © 2016 John Wiley & Sons Ltd.

Analysing the mechanisms of soil water and vapour transport in the desert vadose zone of the extremely arid region of northern China

NASA Astrophysics Data System (ADS)

Du, Chaoyang; Yu, Jingjie; Wang, Ping; Zhang, Yichi

2018-03-01

The transport of water and vapour in the desert vadose zone plays a critical role in the overall water and energy balances of near-surface environments in arid regions. However, field measurements in extremely dry environments face many difficulties and challenges, so few studies have examined water and vapour transport processes in the desert vadose zone. The main objective of this study is to analyse the mechanisms of soil water and vapour transport in the desert vadose zone (depth of ∼350 cm) by using measured and modelled data in an extremely arid environment. The field experiments are implemented in an area of the Gobi desert in northwestern China to measure the soil properties, daily soil moisture and temperature, daily water-table depth and temperature, and daily meteorological records from DOYs (Days of Year) 114-212 in 2014 (growing season). The Hydrus-1D model, which simulates the coupled transport of water, vapour and heat in the vadose zone, is employed to simulate the layered soil moisture and temperature regimes and analyse the transport processes of soil water and vapour. The measured results show that the soil water and temperatures near the land surface have visible daily fluctuations across the entire soil profile. Thermal vapour movement is the most important component of the total water flux and the soil temperature gradient is the major driving factor that affects vapour transport in the desert vadose zone. The most active water and heat exchange occurs in the upper soil layer (depths of 0-25 cm). The matric potential change from the precipitation mainly re-draws the spatio-temporal distribution of the isothermal liquid water in the soil near the land surface. The matric potential has little effect on the isothermal vapour and thermal liquid water flux. These findings offer new insights into the liquid water and vapour movement processes in the extremely arid environment.

Bioinspired one-dimensional materials for directional liquid transport.

PubMed

Ju, Jie; Zheng, Yongmei; Jiang, Lei

2014-08-19

One-dimensional materials (1D) capable of transporting liquid droplets directionally, such as spider silks and cactus spines, have recently been gathering scientists' attention due to their potential applications in microfluidics, textile dyeing, filtration, and smog removal. This remarkable property comes from the arrangement of the micro- and nanostructures on these organisms' surfaces, which have inspired chemists to develop methods to prepare surfaces with similar directional liquid transport ability. In this Account, we report our recent progress in understanding how this directional transport works, as well our advances in the design and fabrication of bioinspired 1D materials capable of transporting liquid droplets directionally. To begin, we first discuss some basic theories on droplet directional movement. Then, we discuss the mechanism of directional transport of water droplets on natural spider silks. Upon contact with water droplets, the spider silk undergoes what is known as a wet-rebuilt, which forms periodic spindle-knots and joints. We found that the resulting gradient of Laplace pressure and surface free energy between the spindle-knots and joints account for the cooperative driving forces to transport water droplets directionally. Next, we discuss the directional transport of water droplets on desert cactus. The integration of multilevel structures of the cactus and the resulting integration of multiple functions together allow the cactus spine to transport water droplets continuously from tip to base. Based on our studies of natural spider silks and cactus spines, we have prepared a series of artificial spider silks (A-SSs) and artificial cactus spines (A-CSs) with various methods. By changing the surface roughness and chemical compositions of the artificial spider silks' spindle-knots, or by introducing stimulus-responsive molecules, such as thermal-responsive and photoresponsive molecules, onto the spindle-knots, we can reversibly manipulate the direction of water droplet's movement on the prepared A-SSs. In addition, the A-SSs with nonuniform spindle-knots, such as multilevel sized spindle-knots and gradient spindle-knots, further demonstrate integrated directional transport ability for water droplets. Through mimicking the main principle of cactus spines in transporting water droplets, we were able to fabricate both single and array A-CSs, which are able to transport liquid droplets directionally both in air and under water. Lastly, we demonstrated some applications of this directional liquid transport, from aspects of efficient fog collection to oil/water separation. In addition, we showed some potential applications in smart catalysis, tracer substance enrichment, smog removal, and drug delivery.

Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications.

PubMed

Hajigholizadeh, Mohammad; Melesse, Assefa M; Fuentes, Hector R

2018-03-14

The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability.

Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications

PubMed Central

Fuentes, Hector R.

2018-01-01

The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability. PMID:29538335

Extended friction elucidates the breakdown of fast water transport in graphene oxide membranes

NASA Astrophysics Data System (ADS)

Montessori, A.; Amadei, C. A.; Falcucci, G.; Sega, M.; Vecitis, C. D.; Succi, S.

2016-12-01

The understanding of water transport in graphene oxide (GO) membranes stands out as a major theoretical problem in graphene research. Notwithstanding the intense efforts devoted to the subject in the recent years, a consolidated picture of water transport in GO membranes is yet to emerge. By performing mesoscale simulations of water transport in ultrathin GO membranes, we show that even small amounts of oxygen functionalities can lead to a dramatic drop of the GO permeability, in line with experimental findings. The coexistence of bulk viscous dissipation and spatially extended molecular friction results in a major decrease of both slip and bulk flow, thereby suppressing the fast water transport regime observed in pristine graphene nanochannels. Inspection of the flow structure reveals an inverted curvature in the near-wall region, which connects smoothly with a parabolic profile in the bulk region. Such inverted curvature is a distinctive signature of the coexistence between single-particle zero-temperature (noiseless) Langevin friction and collective hydrodynamics. The present mesoscopic model with spatially extended friction may offer a computationally efficient tool for future simulations of water transport in nanomaterials.

49 CFR 1090.3 - Use of TOFC/COFC service by motor and water carriers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 8 2012-10-01 2012-10-01 false Use of TOFC/COFC service by motor and water carriers. 1090.3 Section 1090.3 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION GENERAL RULES AND REGULATIONS PRACTICES OF CARRIERS INVOLVED IN THE INTERMODAL MOVEMENT OF...

49 CFR 1090.3 - Use of TOFC/COFC service by motor and water carriers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 8 2014-10-01 2014-10-01 false Use of TOFC/COFC service by motor and water carriers. 1090.3 Section 1090.3 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION GENERAL RULES AND REGULATIONS PRACTICES OF CARRIERS INVOLVED IN THE INTERMODAL MOVEMENT OF...

49 CFR 1090.3 - Use of TOFC/COFC service by motor and water carriers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 8 2011-10-01 2011-10-01 false Use of TOFC/COFC service by motor and water carriers. 1090.3 Section 1090.3 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION GENERAL RULES AND REGULATIONS PRACTICES OF CARRIERS INVOLVED IN THE INTERMODAL MOVEMENT OF...

49 CFR 1090.3 - Use of TOFC/COFC service by motor and water carriers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 8 2013-10-01 2013-10-01 false Use of TOFC/COFC service by motor and water carriers. 1090.3 Section 1090.3 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION GENERAL RULES AND REGULATIONS PRACTICES OF CARRIERS INVOLVED IN THE INTERMODAL MOVEMENT OF...

Anatomical features associated with water transport in imperforate tracheary elements of vessel-bearing angiosperms

PubMed Central

Sano, Yuzou; Morris, Hugh; Shimada, Hiroshi; Ronse De Craene, Louis P.; Jansen, Steven

2011-01-01

Background and Aims Imperforate tracheary elements (ITEs) in wood of vessel-bearing angiosperms may or may not transport water. Despite the significance of hydraulic transport for defining ITE types, the combination of cell structure with water transport visualization in planta has received little attention. This study provides a quantitative analysis of structural features associated with the conductive vs. non-conductive nature of ITEs. Methods Visualization of water transport was studied in 15 angiosperm species by dye injection and cryo-scanning electron microscopy. Structural features of ITEs were examined using light and electron microscopy. Key Results ITEs connected to each other by pit pairs with complete pit membranes contributed to water transport, while cells showing pit membranes with perforations up to 2 µm were hydraulically not functional. A close relationship was found between pit diameter and pit density, with both characters significantly higher in conductive than in non-conductive cells. In species with both conductive and non-conductive ITEs, a larger diameter was characteristic of the conductive cells. Water transport showed no apparent relationship with the length of ITEs and vessel grouping. Conclusions The structure and density of pits between ITEs represent the main anatomical characters determining water transport. The pit membrane structure of ITEs provides a reliable, but practically challenging, criterion to determine their conductive status. It is suggested that the term tracheids should strictly be used for conductive ITEs, while fibre-tracheids and libriform fibres are non-conductive. PMID:21385773

76 FR 27935 - Small Business Size Standards: Transportation and Warehousing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

... within NAICS Industry Group 4883 (Support Activities for Water Transportation), in this rule, SBA also... for Water 488310, 488320, 48830, 488390. Transportation. 4884 Support Activities for Road 488410... 27936

Connection Analysis of Different Modes in Multimodal Transport

NASA Astrophysics Data System (ADS)

Zhao, Zhi; Lu, Ya Ya; Liu, Xing Hua; Jiang, Ying; Zhang, Yan Zhou

2018-06-01

As the most advanced way of transport organization, container multimodal transport provides high quality and efficient systematic logistics transportation services in a wide range of freight transport activities. So it has been widely promoted worldwide. China is in a period of sustained and rapid economic development, which needs greater support from logistics, while the rationalization of multimodal transport enables the best transport area of each transportation mode to be reflected. This paper makes an analysis of the connection between united transportation of railway and highway, rail and water transport and untied transportation of highway and water.

Ion channels versus ion pumps: the principal difference, in principle.

PubMed

Gadsby, David C

2009-05-01

The incessant traffic of ions across cell membranes is controlled by two kinds of border guards: ion channels and ion pumps. Open channels let selected ions diffuse rapidly down electrical and concentration gradients, whereas ion pumps labour tirelessly to maintain the gradients by consuming energy to slowly move ions thermodynamically uphill. Because of the diametrically opposed tasks and the divergent speeds of channels and pumps, they have traditionally been viewed as completely different entities, as alike as chalk and cheese. But new structural and mechanistic information about both of these classes of molecular machines challenges this comfortable separation and forces its re-evaluation.

A geometric framework for dynamics with unilateral constraints and friction, illustrated by an example of self-organized locomotion

NASA Astrophysics Data System (ADS)

Ghosh, Shankar; Merin, A. P.; Bhattacharya, S.; Nitsure, Nitin

2018-04-01

We present a geometric framework to deal with mechanical systems which have unilateral constraints, and are subject to damping/friction, which cannot be treated within usual classical mechanics. In this new framework, the dynamical evolution of the system takes place on a multidimensional curvilinear polyhedron, and energetics near the corners of the polyhedron leads to qualitative behaviour such as stable entrapment and bifurcation. We illustrate this by an experiment in which dumbbells, placed inside a tilted hollow cylindrical drum that rotates slowly around its axis, climb uphill by forming dynamically stable pairs, seemingly against the pull of gravity.

Culture: what is its effect on stress in the military?

PubMed

Langston, Victoria; Gould, Matthew; Greenberg, Neil

2007-09-01

Culture provides the unwritten rules that inform and shape expected behaviors. To date, little research has been conducted into the attitudes or opinions that service personnel hold toward mental health issues. This article examines current literature and research into the recognition of mental health problems in the military and potential organizational barriers to care including stigma and the specific characteristics of a military culture such as the significant reliance on buddy support. We conclude that the barriers to care which operate in both military and civilian populations are not insignificant. Western militaries in fact currently face an uphill struggle to combat the substantial barriers to care that exist.

Agricultural terraces montoring and modeling: a field survey in Chianti region, Firenze, Italy – Second part

NASA Astrophysics Data System (ADS)

Preti, Federico; Caruso, Marco; Dani, Andrea; Cassiani, Giorgio; Romano, Nunzio; Tarolli, Paolo

2015-04-01

The two abstracts present the design and set-up of an experimental campaign which aims at sup-porting the modeling (conceptual and numerical) of water circulation in a terraced slope, and its in-fluence on stability of retaining dry stone walls. The case study is located at "Fattoria di Lamole" (Greve in Chianti, Firenze, Italy). At Lamole site both ancient and recently restored or rebuilt (with different techniques) dry stone walls are present. Furthermore the intense vineyards cultivation makes it very representative in terms of range of external stresses that affect both hillslopes and wall. The survey is developed within the bigger framework of landscape preservation as a way to prevent hydrogeological instabilities and landslide risks. Second Part A second effort is devoted to couple hydrological, hydraulic and geotechnical modeling: - Flow directions and the drainage area have been derived from DTM (high-resolution digital terrain model obtained by a terrestrial laser scanner.), and served for the RPII index calcula-tion (Tarolli et al., 2013), that is coherent with the critical spots observed in situ and marked with GPS. - Direct shear test on undisturbed and reconstituted soil samples will offer an estimation of the Mohr-Coulomb failure envelope parameters (friction angle and cohesion). - Retention curves related with different depths have been derived. - Geoelectric analysis in order to locate the bedrock and to determine the subterranean water flows originated from controlled infitration tests (1 l/s discharge). - A simple dry-wall stability model has been carried out; this model analyses the wall stability with finite elements method, evaluating pressures derived from uphill water infiltration, stone friction and buoyancy in retaining wall layers: simulated deformation are suitable with the observed ones. Acknowledgements Italian Research Project of Relevant Interest (PRIN2010-2011), prot. 20104ALME4, National network for monitoring, modeling, and sustainable management of erosion processes in agricultural land and hilly-mountainous area

Tidally averaged water and salt transport velocities and their distributions in the Pearl River Estuary

NASA Astrophysics Data System (ADS)

Zhu, Shouxian; Sheng, Jinyu; Ji, Xiaomei

2016-09-01

Tidally averaged transports of water and substance are important physical quantities over estuarine, coastal, and shelf waters, but they have been indistinguishably expressed in terms of the Eulerian residual current (ERC) or Lagrangian residual current (LRC) in many previous studies. In this study, the tidally averaged transport velocities for water (TA-WTV) and substance (TA-STV) are considered based on residual fluxes. The main advantage of these newly defined transport velocities is that they can be used to quantify differences in amplitude and direction between the tidally averaged water and substance transports. The two-dimensional TA-STV is interpreted as the transport due to the residual flow of water, tidal pumping, and vertical shear. The three-dimensional TA-STV includes transports from the residual flow of water and tidal pumping. Numerical results of sea surface elevations, currents, and salinity produced by a triply nested coastal ocean model for the Pearl River Estuary (PRE) are used to calculate the TA-WTV and TA-STV for salt (TA-STVsa). The general features of the TA-WTV and TA-STVsa are similar over the most part of the PRE but differ significantly in amplitude and direction over the salinity frontal zone. The ERC and LRC calculated from model results are also significantly different from the TA-STVsa over the salinity frontal zone.

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND...

49 CFR 179.201-10 - Water capacity marking.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Water capacity marking. 179.201-10 Section 179.201-10 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks ...

49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Arch tubes, water bar tubes, circulators and thermic siphons. 230.61 Section 230.61 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Arch tubes, water bar tubes, circulators and thermic siphons. 230.61 Section 230.61 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Arch tubes, water bar tubes, circulators and thermic siphons. 230.61 Section 230.61 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND...

Water and Carbon Footprints for Sustainability Analysis of Urban Infrastructure

EPA Science Inventory

Water and transportation infrastructures define spatial distribution of urban population and economic activities. In this context, energy and water consumed per capita are tangible measures of how efficient water and transportation systems are constructed and operated. At a hig...

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more...

Ground-water models for water resource planning

USGS Publications Warehouse

Moore, J.E.

1983-01-01

In the past decade hydrogeologists have emphasized the development of computer-based mathematical models to aid in the understanding of flow, the transport of solutes, transport of heat, and deformation in the ground-water system. These models have been used to provide information and predictions for water managers. Too frequently, ground-water was neglected in water resource planning because managers believed that it could not be adequately evaluated in terms of availability, quality, and effect of development on surface-water supplies. Now, however, with newly developed digital ground-water models, effects of development can be predicted. Such models have been used to predict hydrologic and quality changes under different stresses. These models have grown in complexity over the last ten years from simple one-layer models to three-dimensional simulations of ground-water flow, which may include solute transport, heat transport, effects of land subsidence, and encroachment of saltwater. Case histories illustrate how predictive ground-water models have provided the information needed for the sound planning and management of water resources in the USA. ?? 1983 D. Reidel Publishing Company.

Cirrus and Water Vapor Transport in the Tropical Tropopause Layer

NASA Astrophysics Data System (ADS)

Dinh, Tra Phuong

Simulations of tropical-tropopause-layer (TTL) cirrus under the influence of a large-scale equatorial Kelvin wave have been performed in two dimensions. These simulations show that, even under the influence of the large-scale wave, radiatively induced dynamics in TTL cirrus plays an important role in the transport of water vapor in the vertical direction. In a typical TTL cirrus, the heating that results from absorption of radiation by ice crystals induces a mesoscale circulation. Advection of ice and water vapor by the radiatively induced circulation leads to the persistence of the cloud and upward advection of the cloudy air. Upward advection of the cloudy air is equivalent to upward transport of water vapor when the air above the cloud is drier than the cloudy air, and downward transport otherwise. In TTL cirrus, microphysical processes also contribute to transport of water vapor in the vertical direction. Ice nucleation and growth, followed by sedimentation and sublimation, always lead to downward transport of water vapor. The magnitude of the downward transport by microphysical processes increases with the relative humidity of the air surrounding the cloud. Moisture in the surrounding environment is important because there is continuous interactions between the cloudy and environmental air throughout the cloud boundary. In our simulations, when the air surrounding the cloud is subsaturated, hence drier than the cloudy air, the magnitude of the downward transport due to microphysical processes is smaller than that of the upward transport due to the radiatively induced advection of water vapor. The net result is upward transport of water vapor, and equivalently hydration of the lower stratosphere. On the other hand, when the surrounding air is supersaturated, hence moister than the cloudy air, microphysical and radiatively induced dynamical processes work in concert to induce downward transport of water vapor, that is dehydration of the lower stratosphere. TTL cirrus processes also depend sensitively on the deposition coefficient of water vapor on ice crystals. The deposition coefficient determines the depositional growth rate of ice crystals, hence microphysical and radiative properties of the cloud. In our simulations, larger values of the deposition coefficient correspond to less ice crystals nucleated during homogeneous freezing, larger ice crystal sizes, faster ice sedimentation, smaller radiative heating rate and weaker dynamics. These results indicate that detailed observations of the relative humidity in the vicinity of TTL cirrus and accurate laboratory measurements of the deposition coefficient are necessary to quantify the impact of TTL cirrus in the dehydration of the stratosphere. This research highlights the complex role of microphysical, radiative and dynamical processes in the transport of water vapor within TTL cirrus. It shows that under certain realistic conditions, TTL cirrus may lead to upward transport of water vapor, which results in moistening of the lower stratosphere. Thus it is not accurate to always associate TTL cirrus with stratospheric dehydration.

The upside-down water collection system of Syntrichia caninervis.

PubMed

Pan, Zhao; Pitt, William G; Zhang, Yuanming; Wu, Nan; Tao, Ye; Truscott, Tadd T

2016-06-06

Desert plants possess highly evolved water conservation and transport systems, from the root structures that maximize absorption of scarce ground water(1-5), to the minimization of leaf surface area(6) to enhance water retention. Recent attention has focused on leaf structures that are adapted to collect water and promote nucleation from humid air(7-9). Syntrichia caninervis Mitt. (Pottiaceae) is one of the most abundant desert mosses in the world and thrives in an extreme environment with multiple but limited water resources (such as dew, fog, snow and rain), yet the mechanisms for water collection and transport have never been completely revealed. S. caninervis has a unique adaptation: it uses a tiny hair (awn) on the end of each leaf to collect water, in addition to that collected by the leaves themselves. Here we show that the unique multiscale structures of the hair are equipped to collect and transport water in four modes: nucleation of water droplets and films on the leaf hair from humid atmospheres; collection of fog droplets on leaf hairs; collection of splash water from raindrops; and transportation of the acquired water to the leaf itself. Fluid nucleation is accomplished in nanostructures, whereas fog droplets are gathered in areas where a high density of small barbs are present and then quickly transported to the leaf at the base of the hair. Our observations reveal nature's optimization of water collection by coupling relevant multiscale physical plant structures with multiscale sources of water.

West-Antarctic Ice Streams: Analog to Ice Flow in Channels on Mars

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1997-01-01

Sounding of the sea floor in front of the Ross Ice Shelf in Antarctica recently revealed large persistent patterns of longitudinal megaflutes and drumlinoid forms, which are interpreted to have formed at the base of ice streams during the list glacial advance. The flutes bear remarkable resemblance to longitudinal grooves and highly elongated streamlined islands found on the floors of some large martian channels, called outflow channels. ln addition, other similarities exist between Antarctic ice streams and outflow channels. Ice streams are 30 to 80 km wide and hundreds of kilometers long, as are the martian channels. Ice stream beds are below sea level. Floors of many martian outflow channels lie below martian datum, which may have been close to or below past martian sea levels. The Antarctic ice stream bed gradient is flat and locally may go uphill, and surface slopes are exceptionally low. So are gradients of martian channels. The depth to the bed in ice streams is 1 to 1.5 km. At bankful stage, the depth of the fluid in outflow channels would have been 1 to 2 km. These similarities suggest that the martian outflow channels, whose origin is commonly attributed to gigantic catastrophic floods, were locally filled by ice that left a conspicuous morphologic imprint. Unlike the West-Antarctic-ice streams, which discharge ice from an ice sheet, ice in the martian channels came from water erupting from the ground. In the cold martian environment, this water, if of moderate volume, would eventually freeze. Thus it may have formed icings on springs, ice dams and jams on constrictions in the channel path, or frozen pools. Given sufficient thickness and downhill surface gradient, these ice masses would have moved; and given the right conditions, they could have moved like Antarctic ice streams.

Early establishment of trees at the alpine treeline: idiosyncratic species responses to temperature-moisture interactions

PubMed Central

Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y.

2016-01-01

On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, tree species ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline tree populations and will depend differently on climatic conditions than adult trees. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline tree species were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia. In addition, we monitored the germination response of three of these species to low temperatures under controlled conditions in growth chambers. The early establishment of these trees at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly species-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each species. We show that temperature and water availability are both important contributors to establishment patterns of treeline trees and hence to species-specific forms and positions of alpine treelines. The observed idiosyncratic species responses highlight the need for studies including several species and life-stages to create predictive power concerning future treeline dynamics. PMID:27402618

Early establishment of trees at the alpine treeline: idiosyncratic species responses to temperature-moisture interactions.

PubMed

Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y

2016-01-01

On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, tree species ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline tree populations and will depend differently on climatic conditions than adult trees. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline tree species were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia In addition, we monitored the germination response of three of these species to low temperatures under controlled conditions in growth chambers. The early establishment of these trees at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly species-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each species. We show that temperature and water availability are both important contributors to establishment patterns of treeline trees and hence to species-specific forms and positions of alpine treelines. The observed idiosyncratic species responses highlight the need for studies including several species and life-stages to create predictive power concerning future treeline dynamics. © The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

The comparative analysis of pre-flood season precipitation and water vapor transportation over guangdong before and after “Hiatus”

NASA Astrophysics Data System (ADS)

Fan, Lingli

2018-02-01

Relation between pre-flood season precipitation and water vapor transport in Guangdong was analysed by using the monthly observed precipitation data, reanalysis data of ERA, NCEP/NCAR, and OAFlux during 1979-2015, and the differences between before/after global warming “hiatus” were studied. Results showed that, after “hiatus”, during the pre-flood season, skin-temperature, evaporation, and the absolute humidity over the ocean near to Southern China was decreasing, and over land was increasing. So, the water cycle over the ocean had slowed down and over land had speed up. The absolute humidity difference between the ocean and the land was reduced. However, at the same time, the total wind speed in Southern China had decreased. So, the water vapor transport from the ocean to the land had reduced. The Eastern Guangdong had an anomalous convergence of meridional water vapor transport, led to increased precipitation; but in Western Guangdong, there was no meridional water vapor transport, so precipitation had a decrease.

Transport and Thermohaline Structure in the Western Tropical North Pacific

NASA Astrophysics Data System (ADS)

Schonau, Martha Coakley

Transport and thermohaline structure of water masses and their respective variability are observed and modeled in the western tropical North Pacific using autonomous underwater gliders, Argo climatology and a numerical ocean state estimate. The North Equatorial Current (NEC) advects subtropical and subpolar water masses into the region that are transported equatorward by the Mindanao Current (MC). Continuous glider observations of these two currents from June 2009 to December 2013 provide absolute geostrophic velocity, water mass structure, and transport. The observations are compared to Argo climatology (Roemmich and Gilson, 2009), wind and precipitation to assess forcing, and annual and interannual variability. Observations are assimilated into a regional ocean state estimate (1/6°) to examine regional transport variability and its relationship to the El Nino-Southern Oscillation phenomena (ENSO). The NEC, described in Chapter 1, is observed along 134.3°E, from 8.5°N to 16.5°N. NEC thermocline transport is relatively constant, with a variable subthermocline transport that is distinguished by countercurrents centered at 9.6°N and 13.1°N. Correlation between thermocline and subthermocline transport is strong. Isopycnals with subducted water masses, the North Pacific Tropical Water and North Pacific Intermediate Water, have the greatest fine-scale thermohaline variance. The NEC advects water masses into the MC, described in Chapter 2, that flows equatorward along the coast of Mindanao. Gliders observed the MC at a mean latitude of 8.5°N. The Mindanao Undercurrent (MUC) persists in the subthermocline offshore of the MC, with a net poleward transport of intermediate water typical of South Pacific origin. The variable subthermocline transport in the MC/MUC has an inverse linear relationship with the Nino 3.4 index and strongly impacts total transport variability. For each the MC and NEC, surface salinity and thermocline depth have a strong relationship with ENSO, and there is relationship between the fine-scale and large-scale isopycnal thermohaline structure. In Chapter 3, a numerical ocean state estimates shows strong interannual variability of regional transport with ENSO. Prior to mature ENSO events, transport in each the NEC, MC and North Equatorial Counter Current (NECC) increase. The increase is from meridional gradients in isopycnal depth related to interannual wind anomalies.

Water Vapor Transport Over the Tropical Oceans During ENSO as Diagnosed from TRMM and SSM/I Data

NASA Technical Reports Server (NTRS)

Robertson, Franklin R.; Smith, Eric A.; Sohn, Byung-Ju

2000-01-01

Traditionally, large-scale water vapor transport [div Q] has been derived directly from circulation statistics in which transport processes are often depicted by mean and eddy motions. Thus detailed and accurate calculations of moisture transport terms over the globe are required. Notably, the lack of systematically spaced conventional measurements of meteorological variables over oceans has hindered understanding of the distribution and transport of water vapor. This motivates the use of indirect calculation methods in which horizontal divergence of water vapor is balanced by the evaporation minus precipitation, assuming the rate of changes of precipitable water and condensates is small over a sufficiently long time period. In order to obtain the water vapor transport, we need evaporation rate minus precipitation (E-P). Focussing on the differences in water vapor transport between El Nino and La Nina periods and their influences on atmospheric circulations, we study January, February, and March of 1998 and 1999 periods which represent El Nino and La Nina respectively. SSM/I-derived precipitation and evaporation rate from SSM/I wind and total precipitable water, in conjunction with NCEP SST and surface air temperature, are used for the calculation of the transport potential function. For the retrieval of evaporation we use a stability-dependent aerodynamic bulk scheme developed by Chou (1993). It was tested against aircraft covariance fluxes measured during cold air outbreaks over the North Atlantic Ocean. Chou et al. (1997) reported that the SSM/I retrieved latent heat flux over the western Pacific warm pool area were found to be comparable with daily mean fluxes of a ship measurements during TOGA/COARE.

Reactive solute transport in an asymmetrical fracture-rock matrix system

NASA Astrophysics Data System (ADS)

Zhou, Renjie; Zhan, Hongbin

2018-02-01

The understanding of reactive solute transport in a single fracture-rock matrix system is the foundation of studying transport behavior in the complex fractured porous media. When transport properties are asymmetrically distributed in the adjacent rock matrixes, reactive solute transport has to be considered as a coupled three-domain problem, which is more complex than the symmetric case with identical transport properties in the adjacent rock matrixes. This study deals with the transport problem in a single fracture-rock matrix system with asymmetrical distribution of transport properties in the rock matrixes. Mathematical models are developed for such a problem under the first-type and the third-type boundary conditions to analyze the spatio-temporal concentration and mass distribution in the fracture and rock matrix with the help of Laplace transform technique and de Hoog numerical inverse Laplace algorithm. The newly acquired solutions are then tested extensively against previous analytical and numerical solutions and are proven to be robust and accurate. Furthermore, a water flushing phase is imposed on the left boundary of system after a certain time. The diffusive mass exchange along the fracture/rock matrixes interfaces and the relative masses stored in each of three domains (fracture, upper rock matrix, and lower rock matrix) after the water flushing provide great insights of transport with asymmetric distribution of transport properties. This study has the following findings: 1) Asymmetric distribution of transport properties imposes greater controls on solute transport in the rock matrixes. However, transport in the fracture is mildly influenced. 2) The mass stored in the fracture responses quickly to water flushing, while the mass stored in the rock matrix is much less sensitive to the water flushing. 3) The diffusive mass exchange during the water flushing phase has similar patterns under symmetric and asymmetric cases. 4) The characteristic distance which refers to the zero diffusion between the fracture and the rock matrix during the water flushing phase is closely associated with dispersive process in the fracture.

Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: implications for a regional risk assessment.

PubMed

Li, Huizhen; Wei, Yanli; Lydy, Michael J; You, Jing

2014-07-01

The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air-water flux, including air-water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air-water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. Copyright © 2014 Elsevier Ltd. All rights reserved.

Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

NASA Astrophysics Data System (ADS)

Muirhead, Daniel

In this thesis, the relative humidity (RH) of the cathode reactant gas was investigated as a factor which influences gas diffusion layer (GDL) liquid water accumulation and mass transport-related efficiency losses over a range of operating current densities in a polymer electrolyte membrane (PEM) fuel cell. Limiting current measurements were used to characterize fuel cell oxygen transport resistance while simultaneous measurements of liquid water accumulation were conducted using synchrotron X-ray radiography. GDL porosity distributions were characterized with micro-computed tomography (microCT). The work presented here can be used by researchers to develop improved numerical models to predict GDL liquid water accumulation and to inform the design of next-generation GDL materials to mitigate mass transport-related efficiency losses. This work also contributes an extensive set of concurrent performance and liquid water visualization data to the PEM fuel cell field that can be used for validating multiphase transport models.

Water and Carbon Footprints for Sustainability Analysis of Urban Infrastructure - abstract

EPA Science Inventory

Water and transportation infrastructures define spatial distribution of urban population and economic activities. In this context, energy and water consumed per capita are tangible measures of how efficient water and transportation systems are constructed and operated. At a hig...

Influence of water and membrane microstructure on the transport properties of proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Siu, Ana Rosa

Proton transport in proton exchange membranes (PEMs) depends on interaction between water and acid groups covalently bound to the polymer. Although the presence of water is important in maintaining the PEM's functions, a thorough understanding of this topic is still lacking. The objective of this work is to provide a better understanding of how the nature water, confined to ionic domains of the polymer, influences the membrane's ability to transport protons, methanol and water. Understanding this topic will facilitate development of new materials with favorable transport properties for fuel cells use. Five classes of polymer membranes were used in this work: polyacrylonitrile-graft-poly(styrenesulfonic) acid (PAN-g-macPSSA); poly(vinylidene difluoride) irradiation-graft-poly(styrenesulfonic) acid (PVDF-g-PSSA); poly(ethylenetetrafluoroethylene) irradiation-graft-poly(styrenesulfonic) acid (ETFE-gPSSA); PVDF-g-PSSA with hydroxyethylmethacrylate (HEMA); and perfluorosulfonic acid membrane (Nafion). The nature of water within the polymers (freezable versus non-freezable states) was measured by systematically freezing samples, and observing the temperature at which water freezes and the amount of heat released in the process. Freezing water-swollen membranes resulted in a 4-fold decrease in the proton conductivity of the PEM. Activation energies of proton transport before and after freezing were ˜ 0.15 eV and 0.5 eV, consistent with proton transport through liquid water and bound water, respectively. Reducing the content of water in membrane samples decreased the amount of freezable and non-freezable water. Calorimetric measurements of membranes in various degrees of hydration showed that water molecules became non-freezable when lambda, (water molecules per sulfonic acid group) was less than ˜14. Proton conduction through membranes containing only non-freezable water was demonstrated to be feasible. Diffusion experiments showed that the permeability of methanol decreased when the content of free water in the membranes decreased. Variation in permeability trends observed for the different polymer classes of the same content of free water was explained on the basis of tortuosity and interaction of methanol within the ionic network. Finally, a novel set of polymers containing non-ionic hydrophilic segments were examined for enhanced water transport in order to see if such domains might offset the flux of water due to electro-osmosis.

ESTCP Cost and Performance Report (ER-200742) Open Burn/Open Detonation (OBOD) Area Management Using Lime for Explosives Transformation and Metals Immobilization

DTIC Science & Technology

2011-10-01

vertical transport of water on the APG OD area. ............................................................... 33  Table 5. Runoff water and leachate ...untreated control soil (study average). There was an insignificant change in leachate pH from Day 1 to Day 9 showing that, while the increase was...explosives from OB/OD area soils have occurred through horizontal transport in surface water and vertical leachate water transport. These pathways

Vapour pressure deficit control in relation to water transport and water productivity in greenhouse tomato production during summer

PubMed Central

Zhang, Dalong; Du, Qingjie; Zhang, Zhi; Jiao, Xiaocong; Song, Xiaoming; Li, Jianming

2017-01-01

Although atmospheric vapour pressure deficit (VPD) has been widely recognized as the evaporative driving force for water transport, the potential to reduce plant water consumption and improve water productivity by regulating VPD is highly uncertain. To bridge this gap, water transport in combination with plant productivity was examined in tomato (Solanum lycopersicum L.) plants grown under contrasting VPD gradients. The driving force for water transport was substantially reduced in low-VPD treatment, which consequently decreased water loss rate and moderated plant water stress: leaf desiccation, hydraulic limitation and excessive negative water potential were prevented by maintaining water balance. Alleviation in water stress by reducing VPD sustained stomatal function and photosynthesis, with concomitant improvements in biomass and fruit production. From physiological perspectives, suppression of the driving force and water flow rate substantially reduced cumulative transpiration by 19.9%. In accordance with physiological principles, irrigation water use efficiency as criterions of biomass and fruit yield in low-VPD treatment was significantly increased by 36.8% and 39.1%, respectively. The reduction in irrigation was counterbalanced by input of fogging water to some extent. Net water saving can be increased by enabling greater planting densities and improving the evaporative efficiency of the mechanical system. PMID:28266524

Osmotic water transport in aquaporins: evidence for a stochastic mechanism

PubMed Central

Zeuthen, Thomas; Alsterfjord, Magnus; Beitz, Eric; MacAulay, Nanna

2013-01-01

We test a novel, stochastic model of osmotic water transport in aquaporins. A solute molecule present at the pore mouth can either be reflected or permeate the pore. We assume that only reflected solute molecules induce osmotic transport of water through the pore, while permeating solute molecules give rise to no water transport. Accordingly, the rate of water transport is proportional to the reflection coefficient σ, while the solute permeability, PS, is proportional to 1 –σ. The model was tested in aquaporins heterologously expressed in Xenopus oocytes. A variety of aquaporin channel sizes and geometries were obtained with the two aquaporins AQP1 and AQP9 and mutant versions of these. Osmotic water transport was generated by adding 20 mm of a range of different-sized osmolytes to the outer solution. The osmotic water permeability and the reflection coefficient were measured optically at high resolution and compared to the solute permeability obtained from short-term uptake of radio-labelled solute under isotonic conditions. For each type of aquaporin there was a linear relationship between solute permeability and reflection coefficient, in accordance with the model. We found no evidence for coupling between water and solute fluxes in the pore. In confirmation of molecular dynamic simulations, we conclude that the magnitude of the osmotic water permeability and the reflection coefficient are determined by processes at the arginine selectivity filter located at the outward-facing end of the pore. PMID:23959676

Finite Difference Formulation for Prediction of Water Pollution

NASA Astrophysics Data System (ADS)

Johari, Hanani; Rusli, Nursalasawati; Yahya, Zainab

2018-03-01

Water is an important component of the earth. Human being and living organisms are demand for the quality of water. Human activity is one of the causes of the water pollution. The pollution happened give bad effect to the physical and characteristic of water contents. It is not practical to monitor all aspects of water flow and transport distribution. So, in order to help people to access to the polluted area, a prediction of water pollution concentration must be modelled. This study proposed a one-dimensional advection diffusion equation for predicting the water pollution concentration transport. The numerical modelling will be produced in order to predict the transportation of water pollution concentration. In order to approximate the advection diffusion equation, the implicit Crank Nicolson is used. For the purpose of the simulation, the boundary condition and initial condition, the spatial steps and time steps as well as the approximations of the advection diffusion equation have been encoded. The results of one dimensional advection diffusion equation have successfully been used to predict the transportation of water pollution concentration by manipulating the velocity and diffusion parameters.

Characterizing the transplanar and in-plane water transport properties of fabrics under different sweat rate: Forced Flow Water Transport Tester

PubMed Central

Tang, K. P. M.; Chau, K. H.; Kan, C. W.; Fan, J. T.

2015-01-01

The water absorption and transport properties of fabrics are critical to wear comfort, especially for sportswear and protective clothing. A new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking properties of fabrics based on gravimetric and image analysis technique. The uniqueness of this instrument is that the rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities. This instrument is versatile in terms of the types of fabrics that can be tested. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Additionally, two graphic methods were proposed to map the direction of liquid transport and its relation to skin wetness, which provides easy and direct comparison among different fabrics. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument. PMID:26593699

Active water transport in unicellular algae: where, why, and how.

PubMed

Raven, John A; Doblin, Martina A

2014-12-01

The occurrence of active water transport (net transport against a free energy gradient) in photosynthetic organisms has been debated for several decades. Here, active water transport is considered in terms of its roles, where it is found, and the mechanisms by which it could occur. First there is a brief consideration of the possibility of active water transport into plant xylem in the generation of root pressure and the refilling of embolized xylem elements, and from an unsaturated atmosphere into terrestrial organisms living in habitats with limited availability of liquid water. There is then a more detailed consideration of volume and osmotic regulation in wall-less freshwater unicells, and the possibility of generation of buoyancy in marine phytoplankton such as large-celled diatoms. Calculations show that active water transport is a plausible mechanism to assist cells in upwards vertical movements, requires less energy than synthesis of low-density organic solutes, and potentially on a par with excluding certain ions from the vacuole. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Characterizing the transplanar and in-plane water transport properties of fabrics under different sweat rate: Forced Flow Water Transport Tester

NASA Astrophysics Data System (ADS)

Tang, K. P. M.; Chau, K. H.; Kan, C. W.; Fan, J. T.

2015-11-01

The water absorption and transport properties of fabrics are critical to wear comfort, especially for sportswear and protective clothing. A new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking properties of fabrics based on gravimetric and image analysis technique. The uniqueness of this instrument is that the rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities. This instrument is versatile in terms of the types of fabrics that can be tested. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Additionally, two graphic methods were proposed to map the direction of liquid transport and its relation to skin wetness, which provides easy and direct comparison among different fabrics. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument.

Characterizing the transplanar and in-plane water transport properties of fabrics under different sweat rate: Forced Flow Water Transport Tester.

PubMed

Tang, K P M; Chau, K H; Kan, C W; Fan, J T

2015-11-23

The water absorption and transport properties of fabrics are critical to wear comfort, especially for sportswear and protective clothing. A new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking properties of fabrics based on gravimetric and image analysis technique. The uniqueness of this instrument is that the rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities. This instrument is versatile in terms of the types of fabrics that can be tested. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Additionally, two graphic methods were proposed to map the direction of liquid transport and its relation to skin wetness, which provides easy and direct comparison among different fabrics. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument.

Photoacoustic monitoring of water transport process in calcareous stone coated with biopolymers

NASA Astrophysics Data System (ADS)

May-Crespo, J.; Ortega-Morales, B. O.; Camacho-Chab, J. C.; Quintana, P.; Alvarado-Gil, J. J.; Gonzalez-García, G.; Reyes-Estebanez, M.; Chan-Bacab, M. J.

2016-12-01

Moisture is a critical control of chemical and physical processes leading to stone deterioration. These processes can be enhanced by microbial biofilms and associated exopolymers (EPS). There is limited current understanding of the water transport process across rocks covered by EPS. In the present work, we employed the photoacoustic technique to study the influence of three biopolymers (xanthan, microbactan and arabic gum) in the water transport process of two types of limestone rock of similar mineralogy but contrasting porosity. Both controls of RL (low porosity) and RP (high porosity) presented the higher values of water diffusion coefficient ( D) than biopolymer-coated samples, indicating that biopolymer layers slowed down the transport of water. This trend was steeper for RP samples as water was transported seven times faster than in the more porous rock. Important differences of D values were observed among samples coated by different biopolymers. Scanning electron microscopy and optical microscopy showed that surface topography was different between both types of rocks; adherence of coatings was seen predominantly in the less porous rocks samples. FTIR and NMR analysis showed the presence of pyruvate and acetate in microbactan and xanthan gum, suggesting their participation on adherence to the calcareous surfaces, sealing surface pores. These results indicate that water transport at rock interfaces is dependent on the chemistry of biopolymer and surface porosity. The implications for reduced water transport in stone conservation under the influence of biopolymers include both enhanced and lower deterioration rates along with altered efficiency of biocide treatment of epilithic biofilms.

Nine years of mass transport data in the eastern boundary of the North Atlantic Subtropical Gyre

NASA Astrophysics Data System (ADS)

Fraile-Nuez, Eugenio; MachíN, Francisco; VéLez-Belchí, Pedro; López-Laatzen, Federico; Borges, Rafael; BeníTez-Barrios, Verónica; HernáNdez-Guerra, Alonso

2010-09-01

One of the longest current meter time series in the Lanzarote Passage in the eastern boundary of the North Atlantic Subtropical Gyre has been used to determine and quantify the 9-year mean transport, the inter-annual and seasonal mass transport variability for the three water masses present in the area. Results show North Atlantic Central Water (NACW) flowing southward in the upper levels with a mean mass transport of -0.81 ± 1.48 Sv, Antarctic Intermediate Water (AAIW) flowing northward at intermediate levels with a mean transport of +0.09 ± 0.57 Sv and Mediterranean Water (MW) flowing southward in the deep part of the passage with a mean transport of -0.05 ± 0.17 Sv. Harmonic and wavelet analysis show the presence of a seasonal pattern in the passage for the three water masses. A maximum southward transport in winter and spring has been observed for the NACW followed by a minimum in summer and fall. Near zero values during winter and spring are found for AAIW, with a maximum northward value in summer and a negative value in fall, when this water mass reverses its flow. MW has a similar seasonal pattern to NACW. The vertical structure in the Lanzarote Passage can be approximated by four significant oscillatory modes which cumulatively explain 86.4% of the variance. The strong transport fluctuation found at the seasonal and inter-annual timescales demonstrates that the Eastern Boundary Current transport has a strong impact on meridional overturning estimates, thus indicating that to understand Meridional Overturning Circulation variability, these transport estimates at the eastern Atlantic margin are necessary.

33 CFR 336.2 - Transportation of dredged material for the purpose of disposal into ocean waters.

Code of Federal Regulations, 2013 CFR

2013-07-01

... material for the purpose of disposal into ocean waters. 336.2 Section 336.2 Navigation and Navigable Waters... WATERS OF THE U.S. AND OCEAN WATERS § 336.2 Transportation of dredged material for the purpose of disposal into ocean waters. (a) Applicable law. Section 103(a) of the ODA provides that the Corps of...

33 CFR 336.2 - Transportation of dredged material for the purpose of disposal into ocean waters.

Code of Federal Regulations, 2014 CFR

2014-07-01

... material for the purpose of disposal into ocean waters. 336.2 Section 336.2 Navigation and Navigable Waters... WATERS OF THE U.S. AND OCEAN WATERS § 336.2 Transportation of dredged material for the purpose of disposal into ocean waters. (a) Applicable law. Section 103(a) of the ODA provides that the Corps of...

Simulating the impact of water storage on agricultural intensification and deforestation in Northern Thailand

NASA Astrophysics Data System (ADS)

Gower, D.; Zeng, Z.; Caylor, K. K.; Wood, E. F.

2017-12-01

In the Nan province of Thailand, agriculture provides a livelihood for much of the population. In the province's lowlands, farmers grow rice, typically with access to irrigation from rivers draining the surrounding mountains. In the uplands, farmers grow rainfed maize, with very little irrigation. Soil erosion from these slopes quickly leads to soil degradation, decreasing yields and forcing farmers to cut down forests to create new farmland. Over the past decades, this practice has led to extensive deforestation throughout the uplands, including within the province's national parks. In response to these issues, the local administration has proposed building upland reservoirs that will provide farmers with greater access to irrigation water and allow them to intensify agricultural production, thus decreasing the need to expand into forested areas. Concerns have been raised, however, about the benefits of such plans as water may need to be pumped uphill from the reservoirs in some cases and soil erosion will remain a problem on the steepest slopes. Such concerns must be investigated before implementation to avoid wasting money on fruitless interventions. This project addresses the above concerns using an agent-based model (ABM) to simulate agricultural production and farmer decision-making in an upland catchment of the Nan province. Here we use HydroBlocks, a field scale land surface model, to simulate soil moisture and runoff at daily-30m resolution. These hydrological variables are integrated in an ABM framework to simulate agricultural production, reservoir capacity and farmer decision-making. As part of the framework, farmers may irrigate their crops using reservoir water but must pay pumping costs that depend on the location of their fields relative to the reservoir. At the end of each growing season, farmers sell their produce and may choose to plant the same crop on the same land, plant a different crop or clear more land for more crops. These decisions change the landscape, feeding back into the HydroBlocks model in subsequent years as changes to the land cover parameters. In this way, the model predicts the long-term impacts of reservoir construction on farmer livelihoods and forest cover in the province.

The Sodium Glucose Cotransporter SGLT1 Is an Extremely Efficient Facilitator of Passive Water Transport.

PubMed

Erokhova, Liudmila; Horner, Andreas; Ollinger, Nicole; Siligan, Christine; Pohl, Peter

2016-04-29

The small intestine is void of aquaporins adept at facilitating vectorial water transport, and yet it reabsorbs ∼8 liters of fluid daily. Implications of the sodium glucose cotransporter SGLT1 in either pumping water or passively channeling water contrast with its reported water transporting capacity, which lags behind that of aquaporin-1 by 3 orders of magnitude. Here we overexpressed SGLT1 in MDCK cell monolayers and reconstituted the purified transporter into proteoliposomes. We observed the rate of osmotic proteoliposome deflation by light scattering. Fluorescence correlation spectroscopy served to assess (i) SGLT1 abundance in both vesicles and plasma membranes and (ii) flow-mediated dilution of an aqueous dye adjacent to the cell monolayer. Calculation of the unitary water channel permeability, pf, yielded similar values for cell and proteoliposome experiments. Neither the absence of glucose or Na(+), nor the lack of membrane voltage in vesicles, nor the directionality of water flow grossly altered pf Such weak dependence on protein conformation indicates that a water-impermeable occluded state (glucose and Na(+) in their binding pockets) lasts for only a minor fraction of the transport cycle or, alternatively, that occlusion of the substrate does not render the transporter water-impermeable as was suggested by computational studies of the bacterial homologue vSGLT. Although the similarity between the pf values of SGLT1 and aquaporin-1 makes a transcellular pathway plausible, it renders water pumping physiologically negligible because the passive flux would be orders of magnitude larger. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Assessment the effect of homogenized soil on soil hydraulic properties and soil water transport

NASA Astrophysics Data System (ADS)

Mohawesh, O.; Janssen, M.; Maaitah, O.; Lennartz, B.

2017-09-01

Soil hydraulic properties play a crucial role in simulating water flow and contaminant transport. Soil hydraulic properties are commonly measured using homogenized soil samples. However, soil structure has a significant effect on the soil ability to retain and to conduct water, particularly in aggregated soils. In order to determine the effect of soil homogenization on soil hydraulic properties and soil water transport, undisturbed soil samples were carefully collected. Five different soil structures were identified: Angular-blocky, Crumble, Angular-blocky (different soil texture), Granular, and subangular-blocky. The soil hydraulic properties were determined for undisturbed and homogenized soil samples for each soil structure. The soil hydraulic properties were used to model soil water transport using HYDRUS-1D.The homogenized soil samples showed a significant increase in wide pores (wCP) and a decrease in narrow pores (nCP). The wCP increased by 95.6, 141.2, 391.6, 3.9, 261.3%, and nCP decreased by 69.5, 10.5, 33.8, 72.7, and 39.3% for homogenized soil samples compared to undisturbed soil samples. The soil water retention curves exhibited a significant decrease in water holding capacity for homogenized soil samples compared with the undisturbed soil samples. The homogenized soil samples showed also a decrease in soil hydraulic conductivity. The simulated results showed that water movement and distribution were affected by soil homogenizing. Moreover, soil homogenizing affected soil hydraulic properties and soil water transport. However, field studies are being needed to find the effect of these differences on water, chemical, and pollutant transport under several scenarios.

Water transport by Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS). The dependence of substrate size studied at high resolution

PubMed Central

Zeuthen*, Thomas; Belhage, Bo; Zeuthen, Emil

2006-01-01

The relation between substrate and water transport was studied in Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS) expressed in Xenopus oocytes. The water transport was monitored from changes in oocyte volume at a resolution of 20 pl, more than one order of magnitude better than previous investigations. The rate of cotransport was monitored as the clamp current obtained from two-electrode voltage clamp. The high resolution data demonstrated a fixed ratio between the turn-over of the cotransporter and the rate of water transport. This applied to experiments in which the rate of cotransport was changed by isosmotic application of substrate, by rapid changes in clamp voltage, or by poisoning. Transport of larger substrates gave rise to less water transport. For the rabbit SGLT1, 378 ± 20 (n = 18 oocytes) water molecules were cotransported along with the 2 Na+ ions and the glucose-analogue α-MDG (MW 194); using the larger sugar arbutin (MW 272) this number was reduced by a factor of at least 0.86 ± 0.03 (15). For the human SGLT1 the respective numbers were 234 ± 12 (18) and 0.85 ± 0.8 (7). For NIS, 253 ± 16 (12) water molecules were cotransported for each 2 Na+ and 1 thiocyanate (SCN−, MW 58), with I− as anion (MW 127) only 162 ± 11 (19) water molecules were cotransported. The effect of substrate size suggests a molecular mechanism for water cotransport and is opposite to what would be expected from unstirred layer effects. Data were analysed by a model which combined cotransport and osmosis at the membrane with diffusion in the cytoplasm. The combination of high resolution measurements and precise modelling showed that water transport across the membrane can be explained by cotransport of water in the membrane proteins and that intracellular unstirred layers effects are minute. PMID:16322051

Computational modeling of transport and electrochemical reactions in proton-exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Um, Sukkee

A comprehensive, multi-physics computational fuel cell dynamics (CFCD) model integrating electrochemical kinetics, charge transport, mass transport (particularly water transport), and flow dynamics is developed in this thesis. The numerical model is validated against published experimental data and utilized to generate results that reveal the internal operation of a PEM fuel cell. A number of model applications are demonstrated in the present work. First, the CFCD model is applied to explore hydrogen dilution effects in the anode feed. Detailed two-dimensional electrochemical and flow/transport simulations are provided to examine substantial anode concentration polarization due to hydrogen depletion at the reaction sites. A transient simulation of the cell current response to a step change in cell voltage is also attempted to elucidate characteristics of the dynamic response of a fuel cell for the first time. After the two-dimensional computational study, the CFCD model is applied to illustrate three-dimensional interactions between mass transfer and electrochemical kinetics. Emphasis is placed on obtaining a fundamental understanding of fully three-dimensional flow in the air cathode with interdigitated flowfield design and how it impacts the transport and electrochemical reaction processes. The innovative design concept for enhanced oxygen transport to, and effective water removal from the cathode, is explored numerically. Next, an analytical study of water transport is performed to investigate various water transport regimes of practical interest. The axial locations characteristic of anode water loss and cathode flooding are predicted theoretically and compared with numerical results. A continuous stirred fuel cell reactor (CSFCR) model is also proposed for the limiting situation where the anode and cathode sides reach equilibrium in water concentration with a thin ionomer membrane in between. In addition to the analytical solutions, a detailed water transport model extending the CFCD framework is developed in which a unified water equation is arrived at using the equilibrium water uptake curve between the gas and membrane phases. Various modes of water transport, i.e. diffusion, convection, and electro-osmotic drag, are incorporated in the unified water transport equation. This water transport model is then applied to elucidate water management in three-dimensional fuel cells with dry to low humidified inlet gases after its validation against available experimental data with dry oxidant and fuel streams. An internal circulation of water with the aid of counter-flow design is found to be essential for low-humidity operation, for example, in portable application of a PEM fuel cell without external humidifier. Finally, to handle the most important issue associated with PEM fuel cells using reformate gas, namely the CO poisoning anode Pt catalysts, a major modification of the present CFCD model is made to include CO oxidation processes. A four-step CO poisoning mechanism is implemented here and anode species equation for CO is added to model the electro- and chemical-oxidation processes on the anode. Numerical results of CO poisoning effects using a commercial package, STAR-CD, are presented. Basic features of CO poisoning are delineated and discussed. Future research areas of the fuel cell modeling are also indicated. As an example, preliminary results of extending the CFCD model to include heat transfer using a commercial package, FLUENTRTM, are given to demonstrate the need for careful thermal management in a multi-cell stack design.

Models for coupling of salt and water transport; Proximal tubular reabsorption in Necturus kidney.

PubMed

Sackin, H; Boulpaep, E L

1975-12-01

Models for coupling of salt and water transport are developed with two important assumptions appropriate for leaky epithelia. (a) The tight junction is permeable to both sale and water. (b) Active Na transport into the lateral speces is assumed to occur uniformly along the length of the channel. The proposed models deal specifically with the intraepithelial mechanism of proximal tubular resbsorption in the Necturus kidney although they have implications for epithelial transport in the gallbladder and small intestine as well. The first model (continuous version) is similar to the standing gradient model devised by Diamond and Bossert but used different boundary conditions. In contrast to Diamond and Bossert's model, the predicted concentration profiles are relatively flat with no sizable gradients along the interspace. The second model (compartment version) expands Curran's model of epithelial salt and water transport by including additional compartments and considering both electrical and chemical driving forces for individual Na and Cl ions as well as hydraulic and osmotic driving forces for water. In both models, ion and water fluxes are investigated as a function of the transport parameters. The behavior of the models is consistent with previously suggested mechanisms for the control of net transport, particularly during saline diuresis. Under all conditions the predicted ratio of net solute to solvent flux, or emergent concentration, deviates from exact isotonicity (except when the basement membrane has an appreciable salt reflection coefficient). However, the degree of hypertonicity may be small enough to be experimentally indistinguishable from isotonic transport.

Climatic Analysis of Oceanic Water Vapor Transports Based on Satellite E-P Datasets

NASA Technical Reports Server (NTRS)

Smith, Eric A.; Sohn, Byung-Ju; Mehta, Vikram

2004-01-01

Understanding the climatically varying properties of water vapor transports from a robust observational perspective is an essential step in calibrating climate models. This is tantamount to measuring year-to-year changes of monthly- or seasonally-averaged, divergent water vapor transport distributions. This cannot be done effectively with conventional radiosonde data over ocean regions where sounding data are generally sparse. This talk describes how a methodology designed to derive atmospheric water vapor transports over the world oceans from satellite-retrieved precipitation (P) and evaporation (E) datasets circumvents the problem of inadequate sampling. Ultimately, the method is intended to take advantage of the relatively complete and consistent coverage, as well as continuity in sampling, associated with E and P datasets obtained from satellite measurements. Independent P and E retrievals from Special Sensor Microwave Imager (SSM/I) measurements, along with P retrievals from Tropical Rainfall Measuring Mission (TRMM) measurements, are used to obtain transports by solving a potential function for the divergence of water vapor transport as balanced by large scale E - P conditions.

Land Ecological on Public Transport Infrastructure Development In Indonesia

NASA Astrophysics Data System (ADS)

Sari, N.

2017-10-01

The development of public transport infrastructure in Indonesia has been growing rapidly since the last five years. The utilization of area as public transport infrastructure, for example bus depot, bus Station and terminal requires wide area and influences many elements, such as land ecological quality, water supplies, power supplies, and environmental balance. However the development of public transport infrastructure now days is less considering on environmental approach, especially for green and catchment area for water conservation (water balance).This paper aims to propose the concept of Public Transport Infrastructure using green concept. The green design concept is using GBCI (Green Building Council Indonesia) standard, which contains seven categories: land ecological enhancement, movement and connectivity, water management and conservation, solid waste and material, community wellbeing strategy, building and energy, and also innovation and future development. The result is, by using the GBCI standard for the green design of Public Transport Infrastructure, the land ecological impact could be decreased. The effective areas that required are at least 5000 m2, from which the green areas for public increase 36% and 76% of areas could be used as catchment area for water conservation.

Influence of coal ash and slag dumping on dump waste waters of the Kostolac power plants (Serbia)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popovic, A.; Djinovic, J.

2006-10-01

The content of selected trace and major elements in the river water used for transport, as well as in the subcategories of the waste waters (overflow and drainage) were analyzed in order to establish the influence of transport and dumping of coal ash and slag from the 'Kostolac A' and 'Kostolac B' power plants located 100 km from Belgrade (Serbia). It was found that during transport of coal ash and slag to the dump, the water used for transport becomes enriched with manganese, nickel, zinc, chromium, vanadium, titanium, cobalt, arsenic, aluminum, and silicon, while more calcium, iron, cadmium, and leadmore » are adsorbed by the ash and slag than is released from them. There is also an equilibrium between the release and adsorption processes of copper and magnesium during transport. The vertical penetration of the water used for transport results in a release of calcium, magnesium, manganese, and cadmium to the environment, while iron, nickel, zinc, chromium, copper, lead, vanadium, titanium, cobalt, and arsenic are adsorbed by the fractions of coal ash and slag in the dump.« less

9 CFR 3.38 - Food and water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Food and water requirements. 3.38... Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.38 Food and water requirements. (a) If... have access to food and water or a type of food, which provides the requirements for food and water in...

9 CFR 3.38 - Food and water requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Food and water requirements. 3.38... Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.38 Food and water requirements. (a) If... have access to food and water or a type of food, which provides the requirements for food and water in...

9 CFR 3.38 - Food and water requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Food and water requirements. 3.38... Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.38 Food and water requirements. (a) If... have access to food and water or a type of food, which provides the requirements for food and water in...

9 CFR 3.38 - Food and water requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Food and water requirements. 3.38... Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.38 Food and water requirements. (a) If... have access to food and water or a type of food, which provides the requirements for food and water in...

Identification of significant transport processes for organic micropollutant classes during soil aquifer treatment (SAT) - a controlled field experiment

NASA Astrophysics Data System (ADS)

Nödler, Karsten; Licha, Tobias; Sauter, Martin

2010-05-01

Supplementing existing water resources with alternative sources of water is a challenge in semi-arid areas, as deterioration of water quality must be avoided. Soil aquifer treatment (SAT) can greatly improve the quality of the injected water by attenuation of organic pollutants via sorption and degradation processes. However, only little is known about the specific transport processes of organic micropollutants under artificial recharge conditions. Organic micropollutants such as pharmaceuticals and their metabolites exhibit a wide range of chemical properties and may undergo very different environmental processes resulting in specific reactions within specified environments. In the presented study fate and transport processes of 25 organic micropollutants (iodinated contrast media, antihypertensive agents, antibiotics, anticonvulsants, lipid regulators, anti-inflammatories, antihistamines and analgesics) were investigated under SAT conditions in a controlled field experiment. Secondary treated effluent (STE) containing the compounds of interest was introduced into the aquifer by an infiltration pond and shallow wells in the vicinity were used for water quality monitoring. By means of strategic sampling procedure and a specialized multi-residue analytical method based on high-performance liquid chromatography / tandem mass spectrometry (LC/MS-MS) 3 main transport processes were identified: 1. Transport of non-polar compounds according to their respective octanol-water distribution coefficient (Kow) 2. Cation exchange 3. Colloidal transport Identification of transport processes 2 & 3 was not expected to act as a transport controlling process. Results of the positively charged beta-blockers sotalol, atenolol and metoprolol gave clear evidence for cation exchange processes of the compounds with the aquifer material. Correlation of turbidity and concentrations of macrolide antibiotics (clarithromycin, erythromycin and roxithromycin) demonstrated the colloidal transport of the respective compounds. Concentrations of almost all micropollutants decreased with increasing soil passage. However, since compounds transported by processes 2 & 3 can be re-mobilized by changing water chemistry, the importance of a diligent characterisation of aquifer material and raw water is apparent for risk assessment. The experiments were conducted within the context of the project GABARDINE, funded by the European Commission.

Plant–Water Relations (1): Uptake and Transport

PubMed Central

2014-01-01

Summary Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow tracheary elements are just one of many adaptations that enable plants to cope with a very dry atmosphere. This lecture examines the physical laws that govern water uptake and transport, the biological properties of cells and plant tissues that facilitate it, and the strategies that enable plants to survive in diverse environments

9 CFR 3.139 - Food and water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Food and water requirements. 3.139..., and Marine Mammals Transportation Standards § 3.139 Food and water requirements. (a) All live animals shall be offered potable water within 4 hours prior to being transported in commerce. Dealers...

9 CFR 3.139 - Food and water requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Food and water requirements. 3.139..., and Marine Mammals Transportation Standards § 3.139 Food and water requirements. (a) All live animals shall be offered potable water within 4 hours prior to being transported in commerce. Dealers...

40 CFR 63.11507 - What are my standards and management practices?

Code of Federal Regulations, 2011 CFR

2011-07-01

... distilled/de-ionized water, water filtration, pre-cleaning of parts to be plated, and thorough rinsing of... emissions from the thermal spraying process and transports the emissions to a water curtain, fabric filter... and transports the emissions to a water curtain, fabric filter, cartridge, or HEPA filter, according...

Students' Conceptions of Water Transport

ERIC Educational Resources Information Center

Rundgren, Carl-Johan; Rundgren, Shu-Nu Chang; Schonborn, Konrad J.

2010-01-01

Understanding diffusion of water into and out of the cell through osmosis is fundamental to the learning and teaching of biology. Although this process is thought of as occurring directly across the lipid bilayer, the majority of water transport is actually mediated by specialised transmembrane water-channels called aquaporins. This study…

A genetic fuzzy analytical hierarchy process based projection pursuit method for selecting schemes of water transportation projects

NASA Astrophysics Data System (ADS)

Jin, Juliang; Li, Lei; Wang, Wensheng; Zhang, Ming

2006-10-01

The optimal selection of schemes of water transportation projects is a process of choosing a relatively optimal scheme from a number of schemes of water transportation programming and management projects, which is of importance in both theory and practice in water resource systems engineering. In order to achieve consistency and eliminate the dimensions of fuzzy qualitative and fuzzy quantitative evaluation indexes, to determine the weights of the indexes objectively, and to increase the differences among the comprehensive evaluation index values of water transportation project schemes, a projection pursuit method, named FPRM-PP for short, was developed in this work for selecting the optimal water transportation project scheme based on the fuzzy preference relation matrix. The research results show that FPRM-PP is intuitive and practical, the correction range of the fuzzy preference relation matrix A it produces is relatively small, and the result obtained is both stable and accurate; therefore FPRM-PP can be widely used in the optimal selection of different multi-factor decision-making schemes.

Trade-offs between water transport capacity and drought resistance in neotropical canopy liana and tree species.

PubMed

De Guzman, Mark E; Santiago, Louis S; Schnitzer, Stefan A; Álvarez-Cansino, Leonor

2017-10-01

In tropical forest canopies, it is critical for upper shoots to efficiently provide water to leaves for physiological function while safely preventing loss of hydraulic conductivity due to cavitation during periods of soil water deficit or high evaporative demand. We compared hydraulic physiology of upper canopy trees and lianas in a seasonally dry tropical forest to test whether trade-offs between safety and efficiency of water transport shape differences in hydraulic function between these two major tropical woody growth forms. We found that lianas showed greater maximum stem-specific hydraulic conductivity than trees, but lost hydraulic conductivity at less negative water potentials than trees, resulting in a negative correlation and trade-off between safety and efficiency of water transport. Lianas also exhibited greater diurnal changes in leaf water potential than trees. The magnitude of diurnal water potential change was negatively correlated with sapwood capacitance, indicating that lianas are highly reliant on conducting capability to maintain leaf water status, whereas trees relied more on stored water in stems to maintain leaf water status. Leaf nitrogen concentration was related to maximum leaf-specific hydraulic conductivity only for lianas suggesting that greater water transport capacity is more tied to leaf processes in lianas compared to trees. Our results are consistent with a trade-off between safety and efficiency of water transport and may have implications for increasing liana abundance in neotropical forests. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Water Permeation through the Sodium-Dependent Galactose Cotransporter vSGLT

PubMed Central

Choe, Seungho; Rosenberg, John M.; Abramson, Jeff; Wright, Ernest M.; Grabe, Michael

2010-01-01

It is well accepted that cotransporters facilitate water movement by two independent mechanisms: osmotic flow through a water channel in the protein and flow driven by ion/substrate cotransport. However, the molecular mechanism of transport-linked water flow is controversial. Some researchers believe that it occurs via cotransport, in which water is pumped along with the transported cargo, while others believe that flow is osmotic in response to an increase in intracellular osmolarity. In this letter, we report the results of a 200-ns molecular dynamics simulation of the sodium-dependent galactose cotransporter vSGLT. Our simulation shows that a significant number of water molecules cross the protein through the sugar-binding site in the presence as well as the absence of galactose, and 70–80 water molecules accompany galactose as it moves from the binding site into the intracellular space. During this event, the majority of water molecules in the pathway are unable to diffuse around the galactose, resulting in water in the inner half of the transporter being pushed into the intracellular space and replaced by extracellular water. Thus, our simulation supports the notion that cotransporters act as both passive water channels and active water pumps with the transported substrate acting as a piston to rectify the motion of water. PMID:20923633

A Better MOC Index: AMOC-θ/S in the North Atlantic Ocean: Spatial Circulation, Water-mass Transformation and Heat Transport on the Temperature/Salinity Plane

NASA Astrophysics Data System (ADS)

Rhines, P. B.; Xu, X.; Chassignet, E.; Schmitz, W. J., Jr.

2016-02-01

An eddy-resolving HYCOM circulation model (driven by a reanalysis atmosphere) shows the structure of the North Atlantic meridional overturning circulation (AMOC), heat transport (MHT) and freshwater transport (MFWT). We project the zonal-mean lateral volume transport, called V(θ,S,y), onto the potential temperature/salinity (θ/S-) plane, and `collapse' V into four zonally integrated volume-transport stream-functions with respect to potential density σ, θ, S and vertical coordinate. The figure shows V(θ,S,y) at 4 latitudes, y, labeled a-d, with northward volume transport in red, southward in blue; Sverdrups of transport are inscribed in σ-bands. Collapsing V onto overturning streamfunctions loses the connection with classic water masses, the hydrologic cycle and convective mode-water production. It is essential that the model resolve boundary currents and the dense northern overflows: model and observations show the dominance of basin-scale AMOC in both MHT and MFWT with potential density, σ, as the vertical coordinate... but much less so with z as a vertical coordinate. With adequate resolution of deep sinking, the Lower North Atlantic Deep Water contributes significantly to MHT. Time-mean MHT and MFWT are dominated by 5-year mean-fields: contributions from annual cycles of velocity and θ are surprisingly small. Quantitative comparison between model and observations at 26N and in the subpolar gyre is supportive of these results. Yet isopycnal processes involving lateral gyres and wind forcing are important. They concentrate the activity of the MOC near western boundaries where essential water-mass transformation (WMT) takes place. V(θ,S,y) transport adds thermohaline `spice' to the MOC, revealing both isopycnal and diapycnal mixing and transport and connects directly with classical water masses. 3-dimensional maps of diapycnal and isopycnal mixing/transport connect internal and externally driven WMT and transports. Particularly important transformation sites are the downslope overflow regions, boundary current extensions (Gulf Stream/North Atlantic Current), mode-water convection sites, deep western boundary currents where topographic transitions occur, and frontal regions (Newfoundland Basin) where northward and southward AMOC branches brush against one another.

Ground-water models for water resources planning

USGS Publications Warehouse

Moore, John E.

1980-01-01

In the past decade hydrologists have emphasized the development of computer-based mathematical models to aid in the understanding of flow, the transport of solutes, transport of heat, and deformation in the groundwater system. These models have been used to provide information and predictions for water managers. Too frequently, groundwater was neglected in water-resource planning because managers believed that it could not be adequately evaluated in terms of availability, quality, and effect of development on surface water supplies. Now, however, with newly developed digital groundwater models, effects of development can be predicted. Such models have been used to predict hydrologic and quality changes under different stresses. These models have grown in complexity over the last 10 years from simple one-layer flow models to three-dimensional simulations of groundwater flow which may include solute transport, heat transport, effects of land subsidence, and encroachment of salt water. This paper illustrates, through case histories, how predictive groundwater models have provided the information needed for the sound planning and management of water resources in the United States. (USGS)

A road damage and life-cycle greenhouse gas comparison of trucking and pipeline water delivery systems for hydraulically fractured oil and gas field development in Colorado

PubMed Central

Duthu, Ray C.

2017-01-01

The process of hydraulic fracturing for recovery of oil and natural gas uses large amounts of fresh water and produces a comparable amount of wastewater, much of which is typically transported by truck. Truck transport of water is an expensive and energy-intensive process with significant external costs including roads damages, and pollution. The integrated development plan (IDP) is the industry nomenclature for an integrated oil and gas infrastructure system incorporating pipeline-based transport of water and wastewater, centralized water treatment, and high rates of wastewater recycling. These IDP have been proposed as an alternative to truck transport systems so as to mitigate many of the economic and environmental problems associated with natural gas production, but the economic and environmental performance of these systems have not been analyzed to date. This study presents a quantification of lifecycle greenhouse gas (GHG) emissions and road damages of a generic oil and gas field, and of an oil and gas development sited in the Denver-Julesburg basin in the northern Colorado region of the US. Results demonstrate that a reduction in economic and environmental externalities can be derived from the development of these IDP-based pipeline water transportation systems. IDPs have marginal utility in reducing GHG emissions and road damage when they are used to replace in-field water transport, but can reduce GHG emissions and road damage by factors of as much as 6 and 7 respectively, when used to replace fresh water transport and waste-disposal routes for exemplar Northern Colorado oil and gas fields. PMID:28686682

A road damage and life-cycle greenhouse gas comparison of trucking and pipeline water delivery systems for hydraulically fractured oil and gas field development in Colorado.

PubMed

Duthu, Ray C; Bradley, Thomas H

2017-01-01

The process of hydraulic fracturing for recovery of oil and natural gas uses large amounts of fresh water and produces a comparable amount of wastewater, much of which is typically transported by truck. Truck transport of water is an expensive and energy-intensive process with significant external costs including roads damages, and pollution. The integrated development plan (IDP) is the industry nomenclature for an integrated oil and gas infrastructure system incorporating pipeline-based transport of water and wastewater, centralized water treatment, and high rates of wastewater recycling. These IDP have been proposed as an alternative to truck transport systems so as to mitigate many of the economic and environmental problems associated with natural gas production, but the economic and environmental performance of these systems have not been analyzed to date. This study presents a quantification of lifecycle greenhouse gas (GHG) emissions and road damages of a generic oil and gas field, and of an oil and gas development sited in the Denver-Julesburg basin in the northern Colorado region of the US. Results demonstrate that a reduction in economic and environmental externalities can be derived from the development of these IDP-based pipeline water transportation systems. IDPs have marginal utility in reducing GHG emissions and road damage when they are used to replace in-field water transport, but can reduce GHG emissions and road damage by factors of as much as 6 and 7 respectively, when used to replace fresh water transport and waste-disposal routes for exemplar Northern Colorado oil and gas fields.

SUPERFUND GROUNDWATER ISSUE - FACILITATED TRANSPORT

EPA Science Inventory

The Regional Superfund Ground Water Forum is a group of ground-water scientists representing EPA's Regional Superfund Offices, organized to exchange up to date information related to ground-water remediation at Superfund sites. Facilitated transport is an issue identified by the ...

VS2DRTI: Simulating Heat and Reactive Solute Transport in Variably Saturated Porous Media.

PubMed

Healy, Richard W; Haile, Sosina S; Parkhurst, David L; Charlton, Scott R

2018-01-29

Variably saturated groundwater flow, heat transport, and solute transport are important processes in environmental phenomena, such as the natural evolution of water chemistry of aquifers and streams, the storage of radioactive waste in a geologic repository, the contamination of water resources from acid-rock drainage, and the geologic sequestration of carbon dioxide. Up to now, our ability to simulate these processes simultaneously with fully coupled reactive transport models has been limited to complex and often difficult-to-use models. To address the need for a simple and easy-to-use model, the VS2DRTI software package has been developed for simulating water flow, heat transport, and reactive solute transport through variably saturated porous media. The underlying numerical model, VS2DRT, was created by coupling the flow and transport capabilities of the VS2DT and VS2DH models with the equilibrium and kinetic reaction capabilities of PhreeqcRM. Flow capabilities include two-dimensional, constant-density, variably saturated flow; transport capabilities include both heat and multicomponent solute transport; and the reaction capabilities are a complete implementation of geochemical reactions of PHREEQC. The graphical user interface includes a preprocessor for building simulations and a postprocessor for visual display of simulation results. To demonstrate the simulation of multiple processes, the model is applied to a hypothetical example of injection of heated waste water to an aquifer with temperature-dependent cation exchange. VS2DRTI is freely available public domain software. © 2018, National Ground Water Association.

Kinetic Theory and Simulation of Single-Channel Water Transport

NASA Astrophysics Data System (ADS)

Tajkhorshid, Emad; Zhu, Fangqiang; Schulten, Klaus

Water translocation between various compartments of a system is a fundamental process in biology of all living cells and in a wide variety of technological problems. The process is of interest in different fields of physiology, physical chemistry, and physics, and many scientists have tried to describe the process through physical models. Owing to advances in computer simulation of molecular processes at an atomic level, water transport has been studied in a variety of molecular systems ranging from biological water channels to artificial nanotubes. While simulations have successfully described various kinetic aspects of water transport, offering a simple, unified model to describe trans-channel translocation of water turned out to be a nontrivial task.

Carbonate-periplatform sedimentation by density flows: A mechanism for rapid off-bank and vertical transport of shallow-water fines

USGS Publications Warehouse

Wilson, P.A.; Roberts, Harry H.

1993-01-01

Existing theories of off-bank sediment transport cannot account for rapid rates of sedimentation observed in Bahama bank and Florida shelf periplatform environments. Analysis of the physical processes operating during winter cold fronts suggests that accelerated off-bank transport of shallow-water mud may be achieved by sinking off-bank flows of sediment-charged hyperpycnal (super-dense) platform waters.

Response of the water status of soybean to changes in soil water potentials controlled by the water pressure in microporous tubes.

PubMed

Steinberg, S L; Henninger, D L

1997-12-01

Water transport through a microporous tube-soil-plant system was investigated by measuring the response of soil and plant water status to step change reductions in the water pressure within the tubes. Soybeans were germinated and grown in a porous ceramic 'soil' at a porous tube water pressure of -0.5 kpa for 28 d. During this time, the soil matric potential was nearly in equilibrium with tube water pressure. Water pressure in the porous tubes was then reduced to either -1.0, -1.5 or -2.0 kPa. Sap flow rates, leaf conductance and soil, root and leaf water potentials were measured before and after this change. A reduction in porous tube water pressure from -0.5 to -1.0 or -1.5 kPa did not result in any significant change in soil or plant water status. A reduction in porous tube water pressure to -2.0 kPa resulted in significant reductions in sap flow, leaf conductance, and soil, root and leaf water potentials. Hydraulic conductance, calculated as the transpiration rate/delta psi between two points in the water transport pathway, was used to analyse water transport through the tube-soil-plant continuum. At porous tube water pressures of -0.5 to-1.5 kPa soil moisture was readily available and hydraulic conductance of the plant limited water transport. At -2.0 kPa, hydraulic conductance of the bulk soil was the dominant factor in water movement.

Response of the water status of soybean to changes in soil water potentials controlled by the water pressure in microporous tubes

NASA Technical Reports Server (NTRS)

Steinberg, S. L.; Henninger, D. L.

1997-01-01

Water transport through a microporous tube-soil-plant system was investigated by measuring the response of soil and plant water status to step change reductions in the water pressure within the tubes. Soybeans were germinated and grown in a porous ceramic 'soil' at a porous tube water pressure of -0.5 kpa for 28 d. During this time, the soil matric potential was nearly in equilibrium with tube water pressure. Water pressure in the porous tubes was then reduced to either -1.0, -1.5 or -2.0 kPa. Sap flow rates, leaf conductance and soil, root and leaf water potentials were measured before and after this change. A reduction in porous tube water pressure from -0.5 to -1.0 or -1.5 kPa did not result in any significant change in soil or plant water status. A reduction in porous tube water pressure to -2.0 kPa resulted in significant reductions in sap flow, leaf conductance, and soil, root and leaf water potentials. Hydraulic conductance, calculated as the transpiration rate/delta psi between two points in the water transport pathway, was used to analyse water transport through the tube-soil-plant continuum. At porous tube water pressures of -0.5 to-1.5 kPa soil moisture was readily available and hydraulic conductance of the plant limited water transport. At -2.0 kPa, hydraulic conductance of the bulk soil was the dominant factor in water movement.

Ocean Transport Pathways to a World Heritage Fringing Coral Reef: Ningaloo Reef, Western Australia.

PubMed

Xu, Jiangtao; Lowe, Ryan J; Ivey, Gregory N; Jones, Nicole L; Zhang, Zhenlin

2016-01-01

A Lagrangian particle tracking model driven by a regional ocean circulation model was used to investigate the seasonally varying connectivity patterns within the shelf circulation surrounding the 300 km long Ningaloo Reef in Western Australia (WA) during 2009-2010. Forward-in-time simulations revealed that surface water was transported equatorward and offshore in summer due to the upwelling-favorable winds. In winter, however, water was transported polewards down the WA coast due to the seasonally strong Leeuwin Current. Using backward-in-time simulations, the subsurface transport pathways revealed two main source regions of shelf water reaching Ningaloo Reef: (1) a year-round source to the northeast in the upper 100 m of water column; and (2) during the summer, an additional source offshore and to the west of Ningaloo in depths between ~30 and ~150 m. Transient wind-driven coastal upwelling, onshore geostrophic transport and stirring by offshore eddies were identified as the important mechanisms influencing the source water origins. The identification of these highly time-dependent transport pathways and source water locations is an essential step towards quantifying how key material (e.g., nutrients, larvae, contaminants, etc.) is exchanged between Ningaloo Reef and the surrounding shelf ocean, and how this is mechanistically coupled to the complex ocean dynamics in this region.

Ebullition, Plant-Mediated Transport, and Subsurface Horizontal Water Flow Dominate Methane Transport in an Arctic Sphagnum Bog

NASA Astrophysics Data System (ADS)

Wehr, R. A.; McCalley, C. K.; Logan, T. A.; Chanton, J.; Crill, P. M.; Rich, V. I.; Saleska, S. R.

2017-12-01

Emission of the greenhouse gas methane from wetlands is of prime concern in the prediction of climate change - especially emission associated with thawing permafrost, which may drive a positive feedback loop of emission and warming. In addition to the biochemistry of methane production and consumption, wetland methane emission depends critically on the transport mechanisms by which methane moves through and out of the ecosystem. We therefore developed a model of methane biochemistry and transport for a sphagnum bog representing an intermediate permafrost thaw stage in Stordalen Mire, Sweden. In order to simultaneously reproduce measured profiles of both the concentrations and isotopic compositions of both methane and carbon dioxide in the peat pore water (Fig. 1) - as well as the surface methane emission - it was necessary for the model to include ebullition, plant-mediated transport via aerenchyma, and subsurface horizontal water flow. Diffusion of gas through the pore water was relatively unimportant. As a result, 90% of the produced methane escaped the wetland rather than being consumed by methanotrophic organisms in the near-surface pore water. Our model provides a comprehensive picture of methane emission from this bog site by quantifying the vertical profiles of: acetoclastic methanogenesis, hydrogenotrophic methanogenesis, methane oxidation, aerobic respiration, ebullition, plant-mediated transport, subsurface horizontal water flow, and diffusion.

Ocean Transport Pathways to a World Heritage Fringing Coral Reef: Ningaloo Reef, Western Australia

PubMed Central

Xu, Jiangtao; Lowe, Ryan J.; Ivey, Gregory N.; Jones, Nicole L.; Zhang, Zhenlin

2016-01-01

A Lagrangian particle tracking model driven by a regional ocean circulation model was used to investigate the seasonally varying connectivity patterns within the shelf circulation surrounding the 300 km long Ningaloo Reef in Western Australia (WA) during 2009–2010. Forward-in-time simulations revealed that surface water was transported equatorward and offshore in summer due to the upwelling-favorable winds. In winter, however, water was transported polewards down the WA coast due to the seasonally strong Leeuwin Current. Using backward-in-time simulations, the subsurface transport pathways revealed two main source regions of shelf water reaching Ningaloo Reef: (1) a year-round source to the northeast in the upper 100 m of water column; and (2) during the summer, an additional source offshore and to the west of Ningaloo in depths between ~30 and ~150 m. Transient wind-driven coastal upwelling, onshore geostrophic transport and stirring by offshore eddies were identified as the important mechanisms influencing the source water origins. The identification of these highly time-dependent transport pathways and source water locations is an essential step towards quantifying how key material (e.g., nutrients, larvae, contaminants, etc.) is exchanged between Ningaloo Reef and the surrounding shelf ocean, and how this is mechanistically coupled to the complex ocean dynamics in this region. PMID:26790154

Sap flow and sugar transport in plants

NASA Astrophysics Data System (ADS)

Jensen, K. H.; Berg-Sørensen, K.; Bruus, H.; Holbrook, N. M.; Liesche, J.; Schulz, A.; Zwieniecki, M. A.; Bohr, T.

2016-07-01

Green plants are Earth's primary solar energy collectors. They harvest the energy of the Sun by converting light energy into chemical energy stored in the bonds of sugar molecules. A multitude of carefully orchestrated transport processes are needed to move water and minerals from the soil to sites of photosynthesis and to distribute energy-rich sugars throughout the plant body to support metabolism and growth. The long-distance transport happens in the plants' vascular system, where water and solutes are moved along the entire length of the plant. In this review, the current understanding of the mechanism and the quantitative description of these flows are discussed, connecting theory and experiments as far as possible. The article begins with an overview of low-Reynolds-number transport processes, followed by an introduction to the anatomy and physiology of vascular transport in the phloem and xylem. Next, sugar transport in the phloem is explored with attention given to experimental results as well as the fluid mechanics of osmotically driven flows. Then water transport in the xylem is discussed with a focus on embolism dynamics, conduit optimization, and couplings between water and sugar transport. Finally, remarks are given on some of the open questions of this research field.

Models for coupling of salt and water transport; Proximal tubular reabsorption in Necturus kidney

PubMed Central

Sackin, H; Boulpaep, EL

1975-01-01

Models for coupling of salt and water transport are developed with two important assumptions appropriate for leaky epithelia. (a) The tight junction is permeable to both sale and water. (b) Active Na transport into the lateral speces is assumed to occur uniformly along the length of the channel. The proposed models deal specifically with the intraepithelial mechanism of proximal tubular resbsorption in the Necturus kidney although they have implications for epithelial transport in the gallbladder and small intestine as well. The first model (continuous version) is similar to the standing gradient model devised by Diamond and Bossert but used different boundary conditions. In contrast to Diamond and Bossert's model, the predicted concentration profiles are relatively flat with no sizable gradients along the interspace. The second model (compartment version) expands Curran's model of epithelial salt and water transport by including additional compartments and considering both electrical and chemical driving forces for individual Na and Cl ions as well as hydraulic and osmotic driving forces for water. In both models, ion and water fluxes are investigated as a function of the transport parameters. The behavior of the models is consistent with previously suggested mechanisms for the control of net transport, particularly during saline diuresis. Under all conditions the predicted ratio of net solute to solvent flux, or emergent concentration, deviates from exact isotonicity (except when the basement membrane has an appreciable salt reflection coefficient). However, the degree of hypertonicity may be small enough to be experimentally indistinguishable from isotonic transport. PMID:1104761

STAND, A DYNAMIC MODEL FOR SEDIMENT TRANSPORT AND WATER QUALITY. (R825758)

EPA Science Inventory

We introduce a new model–STAND (Sediment-Transport-Associated Nutrient Dynamics)–for simulating stream flow, sediment transport, and the interactions of sediment with other attributes of water quality. In contrast to other models, STAND employs a fully dynamic ba...

Continuous directional water transport on the peristome surface of Nepenthes alata

NASA Astrophysics Data System (ADS)

Chen, Huawei; Zhang, Pengfei; Zhang, Liwen; Liu, Hongliang; Jiang, Ying; Zhang, Deyuan; Han, Zhiwu; Jiang, Lei

2016-04-01

Numerous natural systems contain surfaces or threads that enable directional water transport. This behaviour is usually ascribed to hierarchical structural features at the microscale and nanoscale, with gradients in surface energy and gradients in Laplace pressure thought to be the main driving forces. Here we study the prey-trapping pitcher organs of the carnivorous plant Nepenthes alata. We find that continuous, directional water transport occurs on the surface of the ‘peristome’—the rim of the pitcher—because of its multiscale structure, which optimizes and enhances capillary rise in the transport direction, and prevents backflow by pinning in place any water front that is moving in the reverse direction. This results not only in unidirectional flow despite the absence of any surface-energy gradient, but also in a transport speed that is much higher than previously thought. We anticipate that the basic ‘design’ principles underlying this behaviour could be used to develop artificial fluid-transport systems with practical applications.

A coupled hydrodynamic-hydrochemical modeling for predicting mineral transport in a natural acid drainage system.

NASA Astrophysics Data System (ADS)

Zegers Risopatron, G., Sr.; Navarro, L.; Montserrat, S., Sr.; McPhee, J. P.; Niño, Y.

2017-12-01

The geochemistry of water and sediments, coupled with hydrodynamic transport in mountainous channels, is of particular interest in central Chilean Andes due to natural occurrence of acid waters. In this paper, we present a coupled transport and geochemical model to estimate and understand transport processes and fate of minerals at the Yerba Loca Basin, located near Santiago, Chile. In the upper zone, water presentes low pH ( 3) and high concentrations of iron, aluminum, copper, manganese and zinc. Acidity and minerals are the consequence of water-rock interactions in hydrothermal alteration zones, rich in sulphides and sulphates, covered by seasonal snow and glaciers. Downstream, as a consequence of neutral to alkaline lateral water contributions (pH >7) along the river, pH increases and concentration of solutes decreases. The mineral transport model has three components: (i) a hydrodynamic model, where we use HEC-RAS to solve 1D Saint-Venant equations, (ii) a sediment transport model to estimate erosion and sedimentation rates, which quantify minerals transference between water and riverbed and (iii) a solute transport model, based on the 1D OTIS model which takes into account the temporal delay in solutes transport that typically is observed in natural channels (transient storage). Hydrochemistry is solved using PHREEQC, a software for speciation and batch reaction. Our results show that correlation between mineral precipitation and dissolution according to pH values changes along the river. Based on pH measurements (and according to literature) we inferred that main minerals in the water system are brochantite, ferrihydrite, hydrobasaluminite and schwertmannite. Results show that our model can predict the transport and fate of minerals and metals in the Yerba Loca Basin. Mineral dissolution and precipitation process occur for limited ranges of pH values. When pH values are increased, iron minerals (schwertmannite) are the first to precipitate ( 2.5

Antigravity hills are visual illusions.

PubMed

Bressan, Paola; Garlaschelli, Luigi; Barracano, Monica

2003-09-01

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.

Quantum dynamics modeled by interacting trajectories

NASA Astrophysics Data System (ADS)

Cruz-Rodríguez, L.; Uranga-Piña, L.; Martínez-Mesa, A.; Meier, C.

2018-03-01

We present quantum dynamical simulations based on the propagation of interacting trajectories where the effect of the quantum potential is mimicked by effective pseudo-particle interactions. The method is applied to several quantum systems, both for bound and scattering problems. For the bound systems, the quantum ground state density and zero point energy are shown to be perfectly obtained by the interacting trajectories. In the case of time-dependent quantum scattering, the Eckart barrier and uphill ramp are considered, with transmission coefficients in very good agreement with standard quantum calculations. Finally, we show that via wave function synthesis along the trajectories, correlation functions and energy spectra can be obtained based on the dynamics of interacting trajectories.

Photodisproportionation of (. mu. -oxo)bis((tetraphenylporphinato)iron(III))

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richman, R.M.; Peterson, M.W.

1982-10-20

This report proposes an alternative strategy for photochemical solar energy conversion in which the photocatalyst dissociates from an excited state that may react in the strong coupling limit or even predissociate. The key requirement for uphill thermodynamics is that one photoproduct be either a stronger oxidant or a stronger reductant than the starting compound. The requirement for the potential to recycle as a catalyst is that the products not be reactive radicals. A reaction likely to meet these criteria is a photodisproportionation of the form M-O-M ..-->../sup hv/ MVertical BarO + M. This paper reports the first recognized example ofmore » this mechanism for potentially storing energy.« less

Use of oral polio vaccine for polio eradication.

PubMed

Bhatnagar, Pankaj; Bahl, Sunil; Biswal, P

2005-12-01

The experience in three of the world's six WHO Regions (the Americas, the European and the Western Pacific Regions) shows that OPV is the right choice for stopping wild poliovirus transmission. Polio can be eradicated by carrying out SIAs to supplement routine vaccination and by placing added emphasis on reaching every child during every polio round. Monovalent OPV will be key tool in helping us to achieve the goal of polio eradication. The task of global eradication of poliomyelitis is uphill but well within our reach. A strong will and political commitment by the Government of India and effective contributions by each one of us will make our nation polio-free world in the near future.

77 FR 60479 - Burnup Credit in the Criticality Safety Analyses of Pressurized Water Reactor Spent Fuel in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-03

... Pressurized Water Reactor Spent Fuel in Transportation and Storage Casks AGENCY: Nuclear Regulatory Commission... 3, entitled, ``Burnup Credit in the Criticality Safety Analyses of PWR [Pressurized Water Reactor... water reactor spent nuclear fuel (SNF) in transportation packages and storage casks. SFST-ISG-8...

9 CFR 3.89 - Food and water requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... enclosure through the food or water opening. (Approved by the Office of Management and Budget under control... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Food and water requirements. 3.89... Transportation of Nonhuman Primates 2 Transportation Standards § 3.89 Food and water requirements. (a) Each...

Whole-tree water transport scales with sapwood capacitance in tropical forest canopy trees.

Treesearch

F.C. Meinzer; S.A. James; G. Goldstein; D. Woodruff

2003-01-01

The present study examines the manner in which several whole-tree water transport properties scale with species specific variation in sapwood water storage capacity. The hypothesis that constraints on relationships between sapwood capacitance and other water relations characteristics lead to predictable scaling relationships between intrinsic capacitance and whole-tree...

9 CFR 3.89 - Food and water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Food and water requirements. 3.89... Transportation of Nonhuman Primates 2 Transportation Standards § 3.89 Food and water requirements. (a) Each... nonhuman primate must be offered potable water at least once every 12 hours. These time periods apply to...

The Role of Subsurface Properties on Transport of Water and Trace Gases: 1D Simulations at Selected Mars Landing Sites.

NASA Astrophysics Data System (ADS)

Karatekin, O.; Gloesener, E.; Dehant, V. M. A.

2017-12-01

In this work, water ice stability and water vapour transport through porous martian subsurface are studied using a 1D diffusive model. The role of adsorption on water transfer in martian conditions is investigated as well as the range of parameters that have the largest effect on gas transport. In addition, adsorption kinetics is considered to examine its influence on the water vapor exchange between the subsurface and the atmosphere. As methane has been detected in the martian atmosphere, the subsurface model is then used to study methane diffusion in the CH4/CO2/H2O system from variable depths under the surface. The results of subsurface gas transport at selected locations/landing sites are shown and implications for present/future observations are discussed.

Impacts of transportation infrastructure on storm water and surfaces waters in Chittenden County, Vermont, USA.

DOT National Transportation Integrated Search

2014-06-01

Transportation infrastructure is a major source of stormwater runoff that can alter hydrology and : contribute significant loading of nutrients, sediment, and other pollutants to surface waters. These : increased loads can contribute to impairment of...

Shapes of Magnetically Controlled Electron Density Structures in the Dayside Martian Ionosphere

NASA Astrophysics Data System (ADS)

Diéval, C.; Kopf, A. J.; Wild, J. A.

2018-05-01

Nonhorizontal localized electron density structures associated with regions of near-radial crustal magnetic fields are routinely detected via radar oblique echoes on the dayside of Mars with the ionospheric sounding mode of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) radar onboard Mars Express. Previous studies mostly investigated these structures at a fixed plasma frequency and assumed that the larger apparent altitude of the structures compared to the normal surrounding ionosphere implied that they are bulges. However, the signal is subjected to dispersion when it propagates through the plasma, so interpretations based on the apparent altitude should be treated with caution. We go further by investigating the frequency dependence (i.e., the altitude dependence) of the shape of 48 density structure events, using time series of MARSIS electron density profiles corrected for signal dispersion. Four possible simplest shapes are detected in these time series, which can give oblique echoes: bulges, dips, downhill slopes, and uphill slopes. The altitude differences between the density structures and their edges are, in absolute value, larger at low frequency (high altitude) than at high frequency (low altitude), going from a few tens of kilometers to a few kilometers as frequency increases. Bulges dominate in numbers in most of the frequency range. Finally, the geographical extension of the density structures covers a wide range of crustal magnetic fields orientations, with near-vertical fields toward their center and near-horizontal fields toward their edges, as expected. Transport processes are suggested to be a key driver for these density structures.

Molecular determinants for the thermodynamic and functional divergence of uniporter GLUT1 and proton symporter XylE

PubMed Central

Ke, Meng; Jiang, Xin; Yan, Nieng

2017-01-01

GLUT1 facilitates the down-gradient translocation of D-glucose across cell membrane in mammals. XylE, an Escherichia coli homolog of GLUT1, utilizes proton gradient as an energy source to drive uphill D-xylose transport. Previous studies of XylE and GLUT1 suggest that the variation between an acidic residue (Asp27 in XylE) and a neutral one (Asn29 in GLUT1) is a key element for their mechanistic divergence. In this work, we combined computational and biochemical approaches to investigate the mechanism of proton coupling by XylE and the functional divergence between GLUT1 and XylE. Using molecular dynamics simulations, we evaluated the free energy profiles of the transition between inward- and outward-facing conformations for the apo proteins. Our results revealed the correlation between the protonation state and conformational preference in XylE, which is supported by the crystal structures. In addition, our simulations suggested a thermodynamic difference between XylE and GLUT1 that cannot be explained by the single residue variation at the protonation site. To understand the molecular basis, we applied Bayesian network models to analyze the alteration in the architecture of the hydrogen bond networks during conformational transition. The models and subsequent experimental validation suggest that multiple residue substitutions are required to produce the thermodynamic and functional distinction between XylE and GLUT1. Despite the lack of simulation studies with substrates, these computational and biochemical characterizations provide unprecedented insight into the mechanistic difference between proton symporters and uniporters. PMID:28617850

The emerging structure of vacuolar ATPases.

PubMed

Drory, Omri; Nelson, Nathan

2006-10-01

Bioenergetics and physiology of primary pumps have been revitalized by new insights into the mechanism of energizing biomembranes. Structural information is becoming available, and the three-dimensional structure of F-ATPase is being resolved. The growing understanding of the fundamental mechanism of energy coupling may revolutionize our view of biological processes. The F- and V-ATPases (vacuolar-type ATPase) exhibit a common mechanical design in which nucleotide-binding on the catalytic sector, through a cycle of conformation changes, drives the transmembrane passage of protons by turning a membrane-embedded rotor. This motor can run in forward or reverse directions, hydrolyzing ATP as it pumps protons uphill or creating ATP as protons flow downhill. In contrast to F-ATPases, whose primary function in eukaryotic cells is to form ATP at the expense of the proton-motive force (pmf), V-ATPases function exclusively as an ATP-dependent proton pump. The pmf generated by V-ATPases in organelles and membranes of eukaryotic cells is utilized as a driving force for numerous secondary transport processes. V- and F-ATPases have similar structure and mechanism of action, and several of their subunits evolved from common ancestors. Electron microscopy studies of V-ATPase revealed its general structure at low resolution. Recently, several structures of V-ATPase subunits, solved by X-ray crystallography with atomic resolution, were published. This, together with electron microscopy low-resolution maps of the whole complex, and biochemistry cross-linking experiments, allows construction of a structural model for a part of the complex that may be used as a working hypothesis for future research.

Stratospheric Water Vapor and the Asian Monsoon: An Adjoint Model Investigation

NASA Technical Reports Server (NTRS)

Olsen, Mark A.; Andrews, Arlyn E.

2003-01-01

A new adjoint model of the Goddard Parameterized Chemistry and Transport Model is used to investigate the role that the Asian monsoon plays in transporting water to the stratosphere. The adjoint model provides a unique perspective compared to non-diffusive and non-mixing Lagrangian trajectory analysis. The quantity of water vapor transported from the monsoon and the pathways into the stratosphere are examined. The emphasis is on the amount of water originating from the monsoon that contributes to the tropical tape recorder signal. The cross-tropopause flux of water from the monsoon to the midlatitude lower stratosphere will also be discussed.

Electro-osmotic transport in wet processing of textiles

DOEpatents

Cooper, John F.

1998-01-01

Electro-osmotic (or electrokinetic) transport is used to efficiently force a solution (or water) through the interior of the fibers or yarns of textile materials for wet processing of textiles. The textile material is passed between electrodes that apply an electric field across the fabric. Used alone or in parallel with conventional hydraulic washing (forced convection), electro-osmotic transport greatly reduces the amount of water used in wet processing. The amount of water required to achieve a fixed level of rinsing of tint can be reduced, for example, to 1-5 lbs water per pound of fabric from an industry benchmark of 20 lbs water/lb fabric.

Electro-osmotic transport in wet processing of textiles

DOEpatents

Cooper, J.F.

1998-09-22

Electro-osmotic (or electrokinetic) transport is used to efficiently force a solution (or water) through the interior of the fibers or yarns of textile materials for wet processing of textiles. The textile material is passed between electrodes that apply an electric field across the fabric. Used alone or in parallel with conventional hydraulic washing (forced convection), electro-osmotic transport greatly reduces the amount of water used in wet processing. The amount of water required to achieve a fixed level of rinsing of tint can be reduced, for example, to 1--5 lbs water per pound of fabric from an industry benchmark of 20 lbs water/lb fabric. 5 figs.

Magnetic resonance imaging of mass transport and structure inside a phototrophic biofilm.

PubMed

Ramanan, Baheerathan; Holmes, William M; Sloan, William T; Phoenix, Vernon R

2013-05-01

The aim of this study was to utilize magnetic resonance imaging (MRI) to image structural heterogeneity and mass transport inside a biofilm which was too thick for photon based imaging. MRI was used to map water diffusion and image the transport of the paramagnetically tagged macromolecule, Gd-DTPA, inside a 2.5 mm thick cyanobacterial biofilm. The structural heterogeneity of the biofilm was imaged at resolutions down to 22 × 22 μm, enabling the impact of biofilm architecture on the mass transport of both water and Gd-DTPA to be investigated. Higher density areas of the biofilm correlated with areas exhibiting lower relative water diffusion coefficients and slower transport of Gd-DTPA, highlighting the impact of biofilm structure on mass transport phenomena. This approach has potential for shedding light on heterogeneous mass transport of a range of molecular mass molecules in biofilms.

18 CFR 284.267 - Intrastate pipeline emergency transportation rates.

Code of Federal Regulations, 2010 CFR

2010-04-01

... POLICY ACT OF 1978 AND RELATED AUTHORITIES Emergency Natural Gas Sale, Transportation, and Exchange... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Intrastate pipeline emergency transportation rates. 284.267 Section 284.267 Conservation of Power and Water Resources FEDERAL...

Mathematical modelling of fluid transport and its regulation at multiple scales.

PubMed

Chara, Osvaldo; Brusch, Lutz

2015-04-01

Living matter equals water, to a first approximation, and water transport across barriers such as membranes and epithelia is vital. Water serves two competing functions. On the one hand, it is the fundamental solvent enabling random mobility of solutes and therefore biochemical reactions and intracellular signal propagation. Homeostasis of the intracellular water volume is required such that messenger concentration encodes the stimulus and not inverse volume fluctuations. On the other hand, water flow is needed for transport of solutes to and away from cells in a directed manner, threatening volume homeostasis and signal transduction fidelity of cells. Feedback regulation of fluid transport reconciles these competing objectives. The regulatory mechanisms often span across multiple spatial scales from cellular interactions up to the architecture of organs. Open questions relate to the dependency of water fluxes and steady state volumes on control parameters and stimuli. We here review selected mathematical models of feedback regulation of fluid transport at the cell scale and identify a general "core-shell" structure of such models. We propose that fluid transport models at other spatial scales can be constructed in a generalised core-shell framework, in which the core accounts for the biophysical effects of fluid transport whilst the shell reflects the regulatory mechanisms. We demonstrate the applicability of this framework for tissue lumen growth and suggest future experiments in zebrafish to test lumen size regulation mechanisms. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Open Burn/Open Detonation (OBOD) Area Management Using Lime for Explosives Transformation and Metals Immobilization

DTIC Science & Technology

2011-10-01

33  Table 5. Runoff water and leachate estimations as calculated by the HELP model for...was an insignificant change in leachate pH from Day 1 to Day 9 showing that, while the increase was stable, the lime transport, as indicated by pH...horizontal transport in surface water and vertical leachate water transport. These pathways provide a means by which limitations to OB/OD

A New Poisson-Nernst-Planck Model with Ion-Water Interactions for Charge Transport in Ion Channels.

PubMed

Chen, Duan

2016-08-01

In this work, we propose a new Poisson-Nernst-Planck (PNP) model with ion-water interactions for biological charge transport in ion channels. Due to narrow geometries of these membrane proteins, ion-water interaction is critical for both dielectric property of water molecules in channel pore and transport dynamics of mobile ions. We model the ion-water interaction energy based on realistic experimental observations in an efficient mean-field approach. Variation of a total energy functional of the biological system yields a new PNP-type continuum model. Numerical simulations show that the proposed model with ion-water interaction energy has the new features that quantitatively describe dielectric properties of water molecules in narrow pores and are possible to model the selectivity of some ion channels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilmes, Anja, E-mail: Anja.Wilmes@i-med.ac.at; Aschauer, Lydia; Limonciel, Alice

Claudins are the major proteins of the tight junctions and the composition of claudin subtypes is decisive for the selective permeability of the paracellular route and thus tissue specific function. Their regulation is complex and subject to interference by several factors, including oxidative stress. Here we show that exposure of cultured human proximal tubule cells (RPTEC/TERT1) to the immunosuppressive drug cyclosporine A (CsA) induces an increase in transepithelial electrical resistance (TEER), a decrease in dome formation (on solid growth supports) and a decrease in water transport (on microporous growth supports). In addition, CsA induced a dramatic decrease in the mRNAmore » for the pore forming claudins -2 and -10, and the main subunits of the Na{sup +}/K{sup +} ATPase. Knock down of claudin 2 by shRNA had no discernable effect on TEER or dome formation but severely attenuated apical to basolateral water reabsorption when cultured on microporous filters. Generation of an osmotic gradient in the basolateral compartment rescued water transport in claudin 2 knock down cells. Inhibition of Na{sup +}/K{sup +} ATPase with ouabain prevented dome formation in both cell types. Taken together these results provide strong evidence that dome formation is primarily due to transcellular water transport following a solute osmotic gradient. However, in RPTEC/TERT1 cells cultured on filters under iso-osmotic conditions, water transport is primarily paracellular, most likely due to local increases in osmolarity in the intercellular space. In conclusion, this study provides strong evidence that claudin 2 is involved in paracellular water transport and that claudin 2 expression is sensitive to compound induced cellular stress. - Highlights: • Cyclosporine A increased TEER and decreased water transport in RPTEC/TERT1 cells. • Claudins 2 and 10 were decreased in response to cyclosporine A. • Knock down of claudin 2 inhibited water transport in proximal tubular cells. • We propose that claudin 2 is a nephrotoxin sensitive water channel.« less

Recent Approaches to Modeling Transport of Mercury in Surface Water and Groundwater - Case Study in Upper East Fork Poplar Creek, Oak Ridge, TN - 13349

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bostick, Kent; Daniel, Anamary; Tachiev, Georgio

2013-07-01

In this case study, groundwater/surface water modeling was used to determine efficacy of stabilization in place with hydrologic isolation for remediation of mercury contaminated areas in the Upper East Fork Poplar Creek (UEFPC) Watershed in Oak Ridge, TN. The modeling simulates the potential for mercury in soil to contaminate groundwater above industrial use risk standards and to contribute to surface water contamination. The modeling approach is unique in that it couples watershed hydrology with the total mercury transport and provides a tool for analysis of changes in mercury load related to daily precipitation, evaporation, and runoff from storms. The modelmore » also allows for simulation of colloidal transport of total mercury in surface water. Previous models for the watershed only simulated average yearly conditions and dissolved concentrations that are not sufficient for predicting mercury flux under variable flow conditions that control colloidal transport of mercury in the watershed. The transport of mercury from groundwater to surface water from mercury sources identified from information in the Oak Ridge Environmental Information System was simulated using a watershed scale model calibrated to match observed daily creek flow, total suspended solids and mercury fluxes. Mercury sources at the former Building 81-10 area, where mercury was previously retorted, were modeled using a telescopic refined mesh with boundary conditions extracted from the watershed model. Modeling on a watershed scale indicated that only source excavation for soils/sediment in the vicinity of UEFPC had any effect on mercury flux in surface water. The simulations showed that colloidal transport contributed 85 percent of the total mercury flux leaving the UEFPC watershed under high flow conditions. Simulation of dissolved mercury transport from liquid elemental mercury and adsorbed sources in soil at former Building 81-10 indicated that dissolved concentrations are orders of magnitude below a target industrial groundwater concentration beneath the source and would not influence concentrations in surface water at Station 17. This analysis addressed only shallow concentrations in soil and the shallow groundwater flow path in soil and unconsolidated sediments to UEFPC. Other mercury sources may occur in bedrock and transport though bedrock to UEFPC may contribute to the mercury flux at Station 17. Generally mercury in the source areas adjacent to the stream and in sediment that is eroding can contribute to the flux of mercury in surface water. Because colloidally adsorbed mercury can be transported in surface water, actions that trap colloids and or hydrologically isolate surface water runoff from source areas would reduce the flux of mercury in surface water. Mercury in soil is highly adsorbed and transport in the groundwater system is very limited under porous media conditions. (authors)« less

First Principles Study for Proton Transport and Diffusion Behavior in Hydrous Hexagonal WO3

NASA Astrophysics Data System (ADS)

Liu, Chi-Ping; Zhou, Fei; Ozolins, Vidvuds; QPAM Team

2013-03-01

Proton transport is of great importance in biological species and energy storage and conversion systems. Previous studies have shown fast proton conduction in liquids and polymers but seldom in inorganic materials. In this work, first principles density functional theory (DFT) reveals that the formation of hydronium and water chains inside the hexagonal channels plays the key roles for the anomalously fast proton transport, by following modified Grotthuss mechanism. Our DFT study shows the detailed microscopic proton diffusion mechanism along the channel in hydrous WO3 with 50% water composition, which is proper for water chain formation. The water chain in the channel serves as a possible diffusion media for hydronium (H3O +) . With the continuous formation and cleavage of hydrogen bonds in the channel, the hydronium diffuses by hydrogen bonds exchange between water molecules. This mechanism is very similar with Grotthuss relay mechanism for proton transport in liquid. The possible proton diffusion were studied for hydronium is either far away from the water chain bond defect or next to H2O defect at the end of water chain. The diffusion barriers for both conditions are around 150 meV to 200 meV, and water defects reorganization in the chain is the rate-limited step for proton diffusion. These small diffusion barriers could explain the fast 1-D proton transport in hydrous WO3 channel. Further studies about fast proton transport in other inorganic materials could be an important topic in not only biochemistry but also clean energy applications like fuel cell applications.

Control of the Water Transport Activity of Barley HvTIP3;1 Specifically Expressed in Seeds.

PubMed

Utsugi, Shigeko; Shibasaka, Mineo; Maekawa, Masahiko; Katsuhara, Maki

2015-09-01

Tonoplast intrinsic proteins (TIPs) are involved in the transport and storage of water, and control intracellular osmotic pressure by transporting material related to the water potential of cells. In the present study, we focused on HvTIP3;1 during the periods of seed development and desiccation in barley. HvTIP3;1 was specifically expressed in seeds. An immunochemical analysis showed that HvTIP3;1 strongly accumulated in the aleurone layers and outer layers of barley seeds. The water transport activities of HvTIP3;1 and HvTIP1;2, which also accumulated in seeds, were measured in the heterologous expression system of Xenopus oocytes. When they were expressed individually, HvTIP1;2 transported water, whereas HvTIP3;1 did not. However, HvTIP3;1 exhibited water transport activity when co-expressed with HvTIP1;2 in oocytes, and this activity was higher than when HvTIP1;2 was expressed alone. This is the first report to demonstrate that the water permeability of a TIP aquaporin was activated when co-expressed with another TIP. The split-yellow fluorescent protein (YFP) system in onion cells revealed that HvTIP3;1 interacted with HvTIP1;2 to form a heterotetramer in plants. These results suggest that HvTIP3;1 functions as an active water channel to regulate water movement through tissues during the periods of seed development and desiccation. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A High-Resolution Model of Water Mass Transformation and Transport in the Weddell Sea

NASA Astrophysics Data System (ADS)

Hazel, J.; Stewart, A.

2016-12-01

The ocean circulation around the Antarctic margins has a pronounced impact on the global ocean and climate system. One of these impacts includes closing the global meridional overturning circulation (MOC) via formation of dense Antarctic Bottom Water (AABW), which ventilates a large fraction of the subsurface ocean. AABW is also partially composed of modified Circumpolar Deep Water (CDW), a warm, mid-depth water mass whose transport towards the continent has the potential to induce rapid retreat of marine-terminating glaciers. Previous studies suggest that these water mass exchanges may be strongly influenced by high-frequency processes such as downslope gravity currents, tidal flows, and mesoscale/submesoscale eddy transport. However, evaluating the relative contributions of these processes to near-Antarctic water mass transports is hindered by the region's relatively small scales of motion and the logistical difficulties in taking measurements beneath sea ice.In this study we develop a regional model of the Weddell Sea, the largest established source of AABW. The model is forced by an annually-repeating atmospheric state constructed from the Antarctic Mesoscale Prediction System data and by annually-repeating lateral boundary conditions constructed from the Southern Ocean State Estimate. The model incorporates the full Filchner-Ronne cavity and simulates the thermodynamics and dynamics of sea ice. To analyze the role of high-frequency processes in the transport and transformation of water masses, we compute the model's overturning circulation, water mass transformations, and ice sheet basal melt at model horizontal grid resolutions ranging from 1/2 degree to 1/24 degree. We temporally decompose the high-resolution (1/24 degree) model circulation into components due to mean, eddy and tidal flows and discuss the geographical dependence of these processes and their impact on water mass transformation and transport.

Water transport dynamics in trees and stands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pallardy, S.G.; Cermak, J.; Ewers, F.W.

1995-07-01

Water transport dynamics in trees and stands of conifers have certain features that are characteristic of this group and are at least rare among angiosperms. Among these features is the xylem transport system that is dependent on tracheids for long-distance water transport. Tracheid-containing xylem is relatively inefficient, a property that can reduce submaximum allowable rates of gas exchange, but tracheids also offer substantial capacity for water storage and high resistance to freezing-induced dysfunction. Thus, they are quite compatible with the typical evergreen habit and long transpiration season of conifers. At the stand level, canopy transpiration in conifers is primarily controlledmore » by stomatal conductance. In contrast, in dense canopies of angio-sperms, particularly those of tropical forests with limited air mixing, stand transpiration is limited by radiation input rather than by stomatal control. Because of their evergreen habit a greater proportion of evapotranspiration in conifer forests is associated with evaporation of water intercepted by the tree crowns. Other features of transport dynamics are characteristic of most conifers, but are not unique to this group. Among these features are typically shallow root systems that often must supply water in winter to replace transpiration needs of evergreen species, common occurrence of mycorrhizae that enhance mineral and water uptake, and drought tolerance adaptations that include elements of both dehydration avoidance (e.g., stomatal closure under water stress, shifts in allocation of dry matter to below-ground sinks) and dehydration tolerance (e.g., capacity for acclimation of photosynthetic apparatus to drought, osmotic adjustment). Transpiration rates from conifer foliage often are lower than those of deciduous angiosperms, probably because of the lower maximum capacity of tracheid-bearing xylem to transport water.« less

Water permeation through the sodium-dependent galactose cotransporter vSGLT.

PubMed

Choe, Seungho; Rosenberg, John M; Abramson, Jeff; Wright, Ernest M; Grabe, Michael

2010-10-06

It is well accepted that cotransporters facilitate water movement by two independent mechanisms: osmotic flow through a water channel in the protein and flow driven by ion/substrate cotransport. However, the molecular mechanism of transport-linked water flow is controversial. Some researchers believe that it occurs via cotransport, in which water is pumped along with the transported cargo, while others believe that flow is osmotic in response to an increase in intracellular osmolarity. In this letter, we report the results of a 200-ns molecular dynamics simulation of the sodium-dependent galactose cotransporter vSGLT. Our simulation shows that a significant number of water molecules cross the protein through the sugar-binding site in the presence as well as the absence of galactose, and 70-80 water molecules accompany galactose as it moves from the binding site into the intracellular space. During this event, the majority of water molecules in the pathway are unable to diffuse around the galactose, resulting in water in the inner half of the transporter being pushed into the intracellular space and replaced by extracellular water. Thus, our simulation supports the notion that cotransporters act as both passive water channels and active water pumps with the transported substrate acting as a piston to rectify the motion of water. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

23 CFR 645.105 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... to the utility's accounts, if retained for reuse. State transportation department—the transportation..., electricity, light, heat, gas, oil, crude products, water, steam, waste, storm water not connected with...

WASP7 Stream Transport - Model Theory and User's Guide: Supplement to Water Quality Analysis Simulation Program (WASP) User Documentation

EPA Science Inventory

The standard WASP7 stream transport model calculates water flow through a branching stream network that may include both free-flowing and ponded segments. This supplemental user manual documents the hydraulic algorithms, including the transport and hydrogeometry equations, the m...

Comparison of contaminant transport in agricultural drainage water and urban stormwater runoff

USDA-ARS?s Scientific Manuscript database

Transport of nitrogen and phosphorus from agricultural and urban landscapes to surface water bodies can cause adverse environmental impacts including hypoxia and harmful algal blooms. The main objective of this long-term study was to quantify and compare contaminant transport from a subsurface-drain...

Transport of tylosin and tylosin-resistance genes in subsurface drainage water from manured fields

USDA-ARS?s Scientific Manuscript database

Animal agriculture appears to contribute to the spread of antibiotic resistance genes, but few studies have quantified gene transport in agricultural fields. The transport of tylosin, tylosin-resistance genes (erm B, F, A) and tylosin-resistant Enterococcus were measured in tile drainage water from ...

46 CFR 68.33 - Privileges of a limited coastwise endorsement.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Certain Vessels for Oil Spill Cleanup § 68.33 Privileges of a limited coastwise endorsement. (a) A vessel...) To recover oil discharged into the water. (2) To transport oil discharged into the water. (3) To transport and deploy equipment, supplies, and personnel for recovering and transporting oil discharged into...

46 CFR 68.33 - Privileges of a limited coastwise endorsement.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Certain Vessels for Oil Spill Cleanup § 68.33 Privileges of a limited coastwise endorsement. (a) A vessel...) To recover oil discharged into the water. (2) To transport oil discharged into the water. (3) To transport and deploy equipment, supplies, and personnel for recovering and transporting oil discharged into...

46 CFR 68.33 - Privileges of a limited coastwise endorsement.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Certain Vessels for Oil Spill Cleanup § 68.33 Privileges of a limited coastwise endorsement. (a) A vessel...) To recover oil discharged into the water. (2) To transport oil discharged into the water. (3) To transport and deploy equipment, supplies, and personnel for recovering and transporting oil discharged into...

Water uptake and transport in lianas and co-occurring trees of a seasonally dry tropical forest.

Treesearch

José Luis Andrade; Frederick C. Meinzer; Guillermo Goldstein; Stefan A. Schnitzer

2005-01-01

Water uptake and transport were studied in eight liana species in a seasonally dry tropical forest on Barro Colorado Island, Panama. Stable hydrogen isotope composition (δD) of xylem and soil water, soil volumetric water content (θv), and basal sap flow were measured during the 1997 and...

Water transport in human aquaporin-4: molecular dynamics (MD) simulations.

PubMed

Cui, Yubao; Bastien, David A

2011-09-09

Aquaporin-4 (AQP4) is the predominant water channel in the central nervous system, where it has been reported to be involved in many pathophysiological roles including water transport. In this paper, the AQP4 tetramer was modeled from its PDB structure file, embedded in a palmitoyl-oleoyl-phosphatidyl-choline (POPC) lipid bilayer, solvated in water, then minimized and equilibrated by means of molecular dynamics simulations. Analysis of the equilibrated structure showed that the central pore along the fourfold axis of the tetramers is formed with hydrophobic amino acid residues. In particular, Phe-195, Leu-191 and Leu-75, form the narrowest part of the pore. Therefore water molecules are not expected to transport through the central pore, which was confirmed by MD simulations. Each monomer of the AQP4 tetramers forms a channel whose walls consist mostly of hydrophilic residues. There are eight water molecules in single file observed in each of the four channels, transporting through the selectivity filter containing Arg-216, His-201, Phe-77, Ala-210, and the two conserved Asn-Pro-Ala (NPA) motifs containing Asn-213 and Asn-97. By using Brownian dynamics fluctuation-dissipation-theorem (BD-FDT), the overall free-energy profile was obtained for water transporting through AQP4 for the first time, which gives a complete map of the entire channel of water permeation. Copyright © 2011. Published by Elsevier Inc.

Channel morphology effect on water transport through graphene bilayers.

PubMed

Liu, Bo; Wu, Renbing; Law, Adrian Wing-Keung; Feng, Xi-Qiao; Bai, Lichun; Zhou, Kun

2016-12-08

The application of few-layered graphene-derived functional thin films for molecular filtration and separation has recently attracted intensive interests. In practice, the morphology of the nanochannel formed by the graphene (GE) layers is not ideally flat and can be affected by various factors. This work investigates the effect of channel morphology on the water transport behaviors through the GE bilayers via molecular dynamics simulations. The simulation results show that the water flow velocity and transport resistance highly depend on the curvature of the graphene layers, particularly when they are curved in non-synergic patterns. To understand the channel morphology effect, the distributions of water density, dipole moment orientation and hydrogen bonds inside the channel are investigated, and the potential energy surface with different distances to the basal GE layer is analyzed. It shows that the channel morphology significantly changes the distribution of the water molecules and their orientation and interaction inside the channel. The energy barrier for water molecules transport through the channel also significantly depends on the channel morphology.

Channel morphology effect on water transport through graphene bilayers

PubMed Central

Liu, Bo; Wu, Renbing; Law, Adrian Wing-Keung; Feng, Xi-Qiao; Bai, Lichun; Zhou, Kun

2016-01-01

The application of few-layered graphene-derived functional thin films for molecular filtration and separation has recently attracted intensive interests. In practice, the morphology of the nanochannel formed by the graphene (GE) layers is not ideally flat and can be affected by various factors. This work investigates the effect of channel morphology on the water transport behaviors through the GE bilayers via molecular dynamics simulations. The simulation results show that the water flow velocity and transport resistance highly depend on the curvature of the graphene layers, particularly when they are curved in non-synergic patterns. To understand the channel morphology effect, the distributions of water density, dipole moment orientation and hydrogen bonds inside the channel are investigated, and the potential energy surface with different distances to the basal GE layer is analyzed. It shows that the channel morphology significantly changes the distribution of the water molecules and their orientation and interaction inside the channel. The energy barrier for water molecules transport through the channel also significantly depends on the channel morphology. PMID:27929106

Ground-water age and atmospheric tracers: Simulation studies and analysis of field data from the Mirror Lake site, New Hampshire

USGS Publications Warehouse

Goode, Daniel J.

1998-01-01

The use of environmental tracers in characterization of ground-water systems is investigated through mathematical modeling of ground-water age and atmospheric tracer transport, and by a field study at the Mirror Lake site, New Hampshire. Theory is presented for modeling ground-water age using the advective-dispersive transport equation. The transport equation includes a zero-order source of unit strength, corresponding to the rate of aging, and can accommodate matrix diffusion and other exchange processes. The effect of temperature fluctuations and layered soils on transport of atmospheric gases to the water table is investigated using a one-dimensional numerical model of chlorofluorocarbon (CFC-11) transport. The nonlinear relation between temperature and Henry's Law coefficient (reflecting air/water phase partitioning) can cause the apparent recharge temperature to be elevated above the annual mean temperature where the water table is shallow. In addition, fine-grained soils can isolate the air phase in the unsaturated zone from the atmosphere. At the USGS' Mirror Lake, New Hampshire fractured-rock research site CFC concentrations near the water table are depleted where dissolved oxygen is low. CFC-11 and CFC-113 are completely absent under anaerobic conditions, while CFC-12 is as low as one-third of modern concentrations. Anaerobic biodegradation apparently consumes CFC's near the water table at this site. One area of active degradation appears to be associated with streamflow loss to ground water. Soil gas concentrations are generally close to atmospheric levels, although some spatial correlation is observed between depleted concentrations of CFC-11 and CFC-113 in soil gas and water-table samples. Results of unsaturated-zone monitoring indicate that recharge occurs throughout the year in the watershed, even during summer evapotranspiration periods, and that seasonal temperature fluctuations occur as much as 5 meters below land surface. Application of ground-water age and CFC-11 transport models to the large-scale ground-water system at Mirror Lake illustrates the similarities between age and chemical transport. Generally, bedrock porosities required to match observed apparent ages from CFC concentrations are high relative to porosities measured on cores. Although matrix diffusion has no effect on steady-state age, it can significantly reduce CFC concentrations in fractured rock in which the effective porosity is low.

Terrestrial water cycle induced meridional overturning circulation variability over the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Hsu, C. W.; Velicogna, I.

2016-12-01

Terrestrial water cycle has a significant role in the long-term changes of Atlantic meridional overturning circulation (AMOC). With the fresh water input over the ocean from the river runoff or ice melting at the higher latitude, AMOC transport has been predicted to slow down at the end of the century. We compare ocean bottom pressure measured from the GRACE satellite data with the conventional density derived transport observations from the RAPID MOC/MOCHA array to study the impact of the terrestrial water cycle on the seasonal and inter annual AMOC variability detected by the RAPID MOC/MOCHA array observations. We propose that the observed short-term variability is due to coupling of wind driven and terrestrial water cycle changes. We show that the proposed mechanism explains a significant portion of the transport variance and we present new possible mechanism that can explain the residual transport signal in AMOC.

Surface-Water to Groundwater Transport of Pharmaceuticals in a Wastewater-Impacted Stream in the U.S.

NASA Astrophysics Data System (ADS)

Bradley, P. M.; Barber, L. B.; Duris, J. W.; Foreman, W. T.; Furlong, E. T.; Hubbard, L. E.; Hutchinson, K. J.; Keefe, S. H.; Kolpin, D. W.

2014-12-01

Wastewater pharmaceutical contamination of shallow groundwater is a substantial concern in effluent-dominated streams, due to aqueous mobility and designed bioactivity of pharmaceuticals and due to effluent-driven hydraulic gradients. Improved understanding of the environmental fate and transport of wastewater-derived pharmaceuticals is essential for effective protection of vital aquatic ecosystem services, environmental health, and drinking-water supplies. Substantial longitudinal (downstream) transport of pharmaceutical contaminants has been documented in effluent-impacted streams. The comparative lack of information on vertical and lateral transport (infiltration) of wastewater contaminants from surface-water to hyporheic and shallow groundwater compartments is a critical scientific data gap, given the potential for contamination of groundwater supplies in effluent-impacted systems. Growing dependencies on bank filtration and artificial recharge applications for release of wastewater to the environment and for pretreatment of poor-quality surface-water for drinking water emphasize the critical need to better understand the exchange of wastewater contaminants, like pharmaceuticals, between surface-water and groundwater compartments. The potential transport of effluent-derived pharmaceutical contaminants from surface-water to hyporheic-water and shallow groundwater compartments was examined in a wastewater-treatment-facility (WWTF) impacted stream in Ankeny, Iowa under effluent-dominated (71-99% of downstream flow) conditions. Strong hydraulic gradients and hydrologic connectivity were evident between surface-water and shallow-groundwater compartments in the vicinity of the WWTF outfall. Carbamazepine, sulfamethoxazole, and immunologically-related compounds were detected in groundwater 10-20 meters from the stream bank. Direct aqueous-injection HPLC-MS/MS revealed high percentage detections of pharmaceuticals (110 total analytes) in surface-water and groundwater samples. The results demonstrate the importance of effluent discharge as a driver of local hydrologic conditions in an effluent-impacted stream and thus as a fundamental control on surface-water to groundwater transport of effluent-derived pharmaceutical contaminants.

Mountain waves modulate the water vapor distribution in the UTLS

NASA Astrophysics Data System (ADS)

Heller, Romy; Voigt, Christiane; Beaton, Stuart; Dörnbrack, Andreas; Giez, Andreas; Kaufmann, Stefan; Mallaun, Christian; Schlager, Hans; Wagner, Johannes; Young, Kate; Rapp, Markus

2017-12-01

The water vapor distribution in the upper troposphere-lower stratosphere (UTLS) region has a strong impact on the atmospheric radiation budget. Transport and mixing processes on different scales mainly determine the water vapor concentration in the UTLS. Here, we investigate the effect of mountain waves on the vertical transport and mixing of water vapor. For this purpose we analyze measurements of water vapor and meteorological parameters recorded by the DLR Falcon and NSF/NCAR Gulfstream V research aircraft taken during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) in New Zealand. By combining different methods, we develop a new approach to quantify location, direction and irreversibility of the water vapor transport during a strong mountain wave event on 4 July 2014. A large positive vertical water vapor flux is detected above the Southern Alps extending from the troposphere to the stratosphere in the altitude range between 7.7 and 13.0 km. Wavelet analysis for the 8.9 km altitude level shows that the enhanced upward water vapor transport above the mountains is caused by mountain waves with horizontal wavelengths between 22 and 60 km. A downward transport of water vapor with 22 km wavelength is observed in the lee-side of the mountain ridge. While it is a priori not clear whether the observed fluxes are irreversible, low Richardson numbers derived from dropsonde data indicate enhanced turbulence in the tropopause region related to the mountain wave event. Together with the analysis of the water vapor to ozone correlation, we find indications for vertical transport followed by irreversible mixing of water vapor. For our case study, we further estimate greater than 1 W m-2 radiative forcing by the increased water vapor concentrations in the UTLS above the Southern Alps of New Zealand, resulting from mountain waves relative to unperturbed conditions. Hence, mountain waves have a great potential to affect the water vapor distribution in the UTLS. Our regional study may motivate further investigations of the global effects of mountain waves on the UTLS water vapor distributions and its radiative effects.

River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone: U TRANSPORT IN A GROUNDWATER-SURFACE WATER TRANSITION ZONE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachara, John M.; Chen, Xingyuan; Murray, Chris

A tightly spaced well-field within a groundwater uranium (U) plume in the groundwater-surface water transition zone was monitored for a three year period for groundwater elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from mountain snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (Uaq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time series trendsmore » for Uaq and SpC were complex and displayed large temporal well-to well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common temporal behaviors resulting from the intrusion dynamics of river water and the location of source terms. Concentration hot spots were observed in groundwater that varied in location with increasing water table elevation. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While uranium time-series concentration trends varied significantly from year to year as a result of climate-caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of the river water intrusion event.« less

A quantitative approach to aquifer vulnerability mapping

NASA Astrophysics Data System (ADS)

Connell, L. D.; Daele, Gerd van den

2003-05-01

This paper presents a procedure for calculating the transport to groundwater of surface-released contaminants. The approach is derived from a series of analytical and semi-analytical solutions to the advection-dispersion equation that include root zone and unsaturated water movement effects on the transport process. The steady-state form of these equations provides an efficient means of calculating the maximum concentration at the watertable and therefore has potential for use in vulnerability mapping. A two-layer approach is used in the solutions to represent the unsaturated profile, with the root zone corresponding to the upper layer where evapotranspiration can occur and transport properties can be in contrast to the rest of the profile. A novel transformation is applied to the advection-dispersion equation that considerably simplifies the way in which water movement is represented. To provide a combined flow and transport model an approximate procedure for water movement, using averages of the infiltration and transpiration rates with a novel, simple, quasi-steady state solution, is presented that can be used in conjunction with the solutions to the advection-dispersion equation. This quasi-steady state approximation for water movement allows for layering in the soil profile and root water uptake. Results from the combined quasi-steady state water movement and semi-analytical solute transport procedure compare well with numerical solutions to the coupled unsaturated flow and solute transport equations in a series of hypothetical simulations.

Modeling preferential water flow and solute transport in unsaturated soil using the active region model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, F.; Wang, K.; Zhang, R.

2009-03-15

Preferential flow and solute transport are common processes in the unsaturated soil, in which distributions of soil water content and solute concentrations are often characterized as fractal patterns. An active region model (ARM) was recently proposed to describe the preferential flow and transport patterns. In this study, ARM governing equations were derived to model the preferential soil water flow and solute transport processes. To evaluate the ARM equations, dye infiltration experiments were conducted, in which distributions of soil water content and Cl{sup -} concentration were measured. Predicted results using the ARM and the mobile-immobile region model (MIM) were compared withmore » the measured distributions of soil water content and Cl{sup -} concentration. Although both the ARM and the MIM are two-region models, they are fundamental different in terms of treatments of the flow region. The models were evaluated based on the modeling efficiency (ME). The MIM provided relatively poor prediction results of the preferential flow and transport with negative ME values or positive ME values less than 0.4. On the contrary, predicted distributions of soil water content and Cl- concentration using the ARM agreed reasonably well with the experimental data with ME values higher than 0.8. The results indicated that the ARM successfully captured the macroscopic behavior of preferential flow and solute transport in the unsaturated soil.« less

Transport of oxytetracycline, chlortetracycline, and ivermectin in surface runoff from irrigated pasture.

PubMed

Bair, Daniel A; Popova, Ina E; Tate, Kenneth W; Parikh, Sanjai J

2017-09-02

The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.

Evaluation of processes affecting 1,2-dibromo-3-chloropropane (DBCP) concentrations in ground water in the eastern San Joaquin Valley, California : analysis of chemical data and ground-water flow and transport simulations

USGS Publications Warehouse

Burow, Karen R.; Panshin, Sandra Y.; Dubrovsky, Neil H.; Vanbrocklin, David; Fogg, Graham E.

1999-01-01

A conceptual two-dimensional numerical flow and transport modeling approach was used to test hypotheses addressing dispersion, transformation rate, and in a relative sense, the effects of ground- water pumping and reapplication of irrigation water on DBCP concentrations in the aquifer. The flow and transport simulations, which represent hypothetical steady-state flow conditions in the aquifer, were used to refine the conceptual understanding of the aquifer system rather than to predict future concentrations of DBCP. Results indicate that dispersion reduces peak concentrations, but this process alone does not account for the apparent decrease in DBCP concentrations in ground water in the eastern San Joaquin Valley. Ground-water pumping and reapplication of irrigation water may affect DBCP concentrations to the extent that this process can be simulated indirectly using first-order decay. Transport simulation results indicate that the in situ 'effective' half-life of DBCP caused by processes other than dispersion and transformation to BAA could be on the order of 6 years.

Water transport inside carbon nanotubes mediated by phonon-induced oscillating friction.

PubMed

Ma, Ming; Grey, François; Shen, Luming; Urbakh, Michael; Wu, Shuai; Liu, Jefferson Zhe; Liu, Yilun; Zheng, Quanshui

2015-08-01

The emergence of the field of nanofluidics in the last decade has led to the development of important applications including water desalination, ultrafiltration and osmotic energy conversion. Most applications make use of carbon nanotubes, boron nitride nanotubes, graphene and graphene oxide. In particular, understanding water transport in carbon nanotubes is key for designing ultrafiltration devices and energy-efficient water filters. However, although theoretical studies based on molecular dynamics simulations have revealed many mechanistic features of water transport at the molecular level, further advances in this direction are limited by the fact that the lowest flow velocities accessible by simulations are orders of magnitude higher than those measured experimentally. Here, we extend molecular dynamics studies of water transport through carbon nanotubes to flow velocities comparable with experimental ones using massive crowd-sourced computing power. We observe previously undetected oscillations in the friction force between water and carbon nanotubes and show that these oscillations result from the coupling between confined water molecules and the longitudinal phonon modes of the nanotube. This coupling can enhance the diffusion of confined water by more than 300%. Our results may serve as a theoretical framework for the design of new devices for more efficient water filtration and osmotic energy conversion devices.

Optimum design for effective water transport through a double-layered porous hydrogel inspired by plant leaves

NASA Astrophysics Data System (ADS)

Kim, Hyejeong; Kim, Hyeonjeong; Huh, Hyungkyu; Hwang, Hyung Ju; Lee, Sang Joon

2014-11-01

Plant leaves are generally known to have optimized morphological structure in response to environmental changes for efficient water usage. However, the advantageous features of plant leaves are not fully utilized in engineering fields yet, since the optimum design in internal structure of plant leaves is unclear. In this study, the tissue organization of the hydraulic pathways inside plant leaves was investigated. Water transport through double-layered porous hydrogel models analogous to mesophyll cells was experimentally observed. In addition, computational experiment and theoretical analysis were applied to the model systems to find the optimal design for efficient water transport. As a result, the models with lower porosity or with pores distributed widely in the structure exhibit efficient mass transport. Our theoretical prediction supports that structural features of plant leaves guarantee sufficient water supply as survival strategy. This study may provide a new framework for investigating the biophysical principles governing the morphological optimization of plant leaves and for designing microfluidic devices to enhance mass transport ability. This study was supported by the National Research Foundation of Korea and funded by the Korean government.

Hydrocyclonic separation of invasive New Zealand mudsnails from an aquaculture water source

USGS Publications Warehouse

Nielson, R. Jordan; Moffitt, Christine M.; Watten, Barnaby J.

2012-01-01

Invasive New Zealand mudsnails (Potamopyrgus antipodarum, NZMS) have infested freshwater aquaculture facilities in the western United States and disrupted stocking or fish transportation activities because of the risk of transporting NZMS to naive locations. We tested the efficacy of a gravity-fed, hydrocyclonicseparation system to remove NZMS from an aquaculture water source at two design flows: 367 L/min and 257 L/min. The hydrocyclone effectively filtered all sizes of snails (including newly emerged neonates) from inflows. We modeled cumulative recovery of three sizes of snails, and determined that both juvenile and adult sized snails were transported similarly through the filtration system, but the transit of neonates was faster and similar to the transport of water particles. We found that transit times through the filtration system were different between the two flows regardless of snail size, and the hydrocyclone filter operated more as a plug flow system with dispersion, especially when transporting and removing the larger sized adult and juvenile sized snails. Our study supports hydrocyclonic filtration as an important tool to provide snail free water for aquaculture operations that require uninfested water sources.

Distributed source pollutant transport module based on BTOPMC: a case study of the Laixi River basin in the Sichuan province of southwest China

NASA Astrophysics Data System (ADS)

Zhang, Hongbo; Ao, Tianqi; Gusyev, Maksym; Ishidaira, Hiroshi; Magome, Jun; Takeuchi, Kuniyoshi

2018-06-01

Nitrogen and phosphorus concentrations in Chinese river catchments are contributed by agricultural non-point and industrial point sources causing deterioration of river water quality and degradation of ecosystem functioning for a long distance downstream. To evaluate these impacts, a distributed pollutant transport module was developed on the basis of BTOPMC (Block-Wise Use of TOPMODEL with Muskingum-Cunge Method), a grid-based distributed hydrological model, using the water flow routing process of BTOPMC as the carrier of pollutant transport due a direct runoff. The pollutant flux at each grid is simulated based on mass balance of pollutants within the grid and surface water transport of these pollutants occurs between grids in the direction of the water flow on daily time steps. The model was tested in the study area of the Lu county area situated in the Laixi River basin in the Sichuan province of southwest China. The simulated concentrations of nitrogen and phosphorus are compared with the available monthly data at several water quality stations. These results demonstrate a greater pollutant concentration in the beginning of high flow period indicating the main mechanism of pollution transport. From these preliminary results, we suggest that the distributed pollutant transport model can reflect the characteristics of the pollutant transport and reach the expected target.

Three-dimensional, high-resolution skeletal kinematics of the avian wing and shoulder during ascending flapping flight and uphill flap-running.

PubMed

Baier, David B; Gatesy, Stephen M; Dial, Kenneth P

2013-01-01

Past studies have shown that birds use their wings not only for flight, but also when ascending steep inclines. Uphill flap-running or wing-assisted incline running (WAIR) is used by both flight-incapable fledglings and flight-capable adults to retreat to an elevated refuge. Despite the broadly varying direction of travel during WAIR, level, and descending flight, recent studies have found that the basic wing path remains relatively invariant with reference to gravity. If so, joints undergo disparate motions to maintain a consistent wing path during those specific flapping modes. The underlying skeletal motions, however, are masked by feathers and skin. To improve our understanding of the form-functional relationship of the skeletal apparatus and joint morphology with a corresponding locomotor behavior, we used XROMM (X-ray Reconstruction of Moving Morphology) to quantify 3-D skeletal kinematics in chukars (Alectoris chukar) during WAIR (ascending with legs and wings) and ascending flight (AF, ascending with wings only) along comparable trajectories. Evidence here from the wing joints demonstrates that the glenohumeral joint controls the vast majority of wing movements. More distal joints are primarily involved in modifying wing shape. All bones are in relatively similar orientations at the top of upstroke during both behaviors, but then diverge through downstroke. Total excursion of the wing is much smaller during WAIR and the tip of the manus follows a more vertical path. The WAIR stroke appears "truncated" relative to ascending flight, primarily stemming from ca. 50% reduction in humeral depression. Additionally, the elbow and wrist exhibit reduced ranges of angular excursions during WAIR. The glenohumeral joint moves in a pattern congruent with being constrained by the acrocoracohumeral ligament. Finally, we found pronounced lateral bending of the furcula during the wingbeat cycle during ascending flight only, though the phasic pattern in chukars is opposite of that observed in starlings (Sturnus vulgaris).

The influence of increased distal loading on metabolic cost, efficiency, and kinematics of roller ski skating.

PubMed

Bolger, Conor M; Bessone, Veronica; Federolf, Peter; Ettema, Gertjan; Sandbakk, Øyvind

2018-01-01

The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P<0.001 and P = 0.002). At 5% incline, no change in metabolic rate or gross efficiency was found (P = 0.89 and P = 0.11). Rating of perceived exertion (RPE) increased gradually with added weight at both inclines (P>0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.

Energy requirements of tire pulling.

PubMed

Fredriksen, Per M; Mamen, Asgeir

2017-10-01

We have investigated the effect using walking poles and pulling tires at 4 and 6 km·h-1 (1.11 and 1.67 m·s-1) speeds on oxygen uptake (V̇O2) and heart rate. Eleven subjects, 6 males, with a mean (SD) age of 25.2 (6.9) years participated in field tests involving walking without poles, walking with poles and tire pulling with poles. Increasing the load caused the largest increases in energy demand, more than 4 MET. Speed increase also caused substantial energy increase, approximately 4 MET. Increasing the inclination only modestly increased the oxygen uptake, approximately 2 MET. In both level walking and uphill walking, using poles marginally increased oxygen uptake compared to working without poles. Pulling one tire (12.5 kg) required an oxygen uptake of 27 (4) mL·kg-1·min-1 at 4 km·h-1 and 0% inclination. Adding one more tire (6 kg) drove the oxygen uptake further up to 39 (4) mL·kg-1·min-1. This is close to the requirement of level running at 10.5 km·h-1. Pulling both tires at 6 km·h-1 and 5% inclination required a V̇O2 of 54 (6) mL·kg-1·min-1, equal to running uphill at 5% inclination and 12.5 km·h-1 speed. Heart rate rose comparably with oxygen uptake. At 4 km·h-1 and 0% inclination the increase was 29 bpm, from 134 (21) to 163 (22) bpm when going from pulling one tire to two tires. In the hardest exercise, 6 km·h-1 and 5% inclination, heart rate reached 174 (14) bpm. The study showed that tire pulling even at slow speeds has an energy requirement that is so large that the activity may be feasible as endurance training.

Anatomic single-bundle anterior cruciate ligament reconstruction improves walking economy: hamstrings tendon versus patellar tendon grafts.

PubMed

Iliopoulos, Efthymios; Galanis, Nikiforos; Zafeiridis, Andreas; Iosifidis, Michael; Papadopoulos, Pericles; Potoupnis, Michael; Geladas, Nikolaos; Vrabas, Ioannis S; Kirkos, John

2017-10-01

Anterior cruciate ligament (ACL) injury is associated with a pathologic gait pattern and increased energy cost during locomotion. ACL reconstruction could improve the gait pattern. Hamstrings tendon (HAM) and bone-patellar tendon-bone (BPTB) grafts are usually used for reconstruction. The aim of this study was to compare the efficacy of anatomic ACL reconstruction with HAM and BPTB grafts on improving and normalizing the energy cost and physiologic reserves during flat, uphill, and downhill walking. Twenty male subjects with unilateral ACL injuries were randomly assigned to ACL reconstruction with a HAM (n = 10) or BPTB (n = 10) graft. Ten matched controls were also enrolled. All participants performed three 8-min walking tasks at 0, +10, and -10 % gradients before and 9 months after surgery. Energy cost (oxygen consumption, VO 2 ), heart rate (HR), and ventilation (VE) were measured. Lysholm/IKDC scores were recorded. Pre-operatively, VO 2 , HR, and VE were higher in the HAM and BPTB groups than in controls during walking at 0, +10, and -10 % gradients (p < 0.001-0.01). Post-operatively, both HAM and BPTB groups showed reduced VO 2 , HR, and VE during the three walking tasks (p < 0.001-0.01). Although the post-operative VO 2 in both surgical groups reached 90-95 % of the normative (control) value during walking, it remained elevated against the value observed in controls (p < 0.001-0.01). The HAM and BPTB groups showed no differences in post-surgical VO 2 or HR during walking at all three gradients. Anatomic ACL reconstruction with either HAM or BPTB graft resulted in similar short-term improvements in energy cost and nearly normalized locomotion economy and cardiorespiratory reserves during flat, uphill, and downhill walking. The improved locomotion economy is an additional benefit of anatomic ACL reconstruction, irrespective of the type of graft used, that the orthopaedic surgeons should consider. II.

Anterior cruciate ligament deficiency reduces walking economy in "copers" and "non-copers".

PubMed

Iliopoulos, Efthymios; Galanis, Nikiforos; Iosifidis, Michael; Zafeiridis, Andreas; Papadopoulos, Pericles; Potoupnis, Michael; Geladas, Nikolaos; Vrabas, Ioannis S; Kirkos, John

2017-05-01

Patients with ACL injury requiring surgical treatment (non-copers) demonstrate altered neuromuscular control and gait pattern compared with those returning to their pre-injury activities without surgery (copers). Pathological gait pattern may increase the energy cost of walking. We compared the energy cost of flat, uphill, and downhill walking between ACL-deficient and healthy individuals and between "copers" and "non-copers". Nineteen young males with unilateral ACL injury were allocated into "copers" and "non-copers" according to their ability to return to pre-injury activity without ACL reconstruction. Lysholm and IKDC scales were recorded, and a control group (n = 10) matched for physical characteristics and activity levels was included. All participants performed 8-min walking tasks at 0, +10, and -10 % gradients. Energy cost was assessed by measurement of oxygen consumption (VO 2 ). HR and ventilation (VE), respiratory exchange ratio (RER), and VE/VO 2 were also measured. VO 2 and HR were higher in ACL-deficient patients than in controls during walking at 0, +10, and -10 % gradients (p < 0.01-0.05). There were no differences between "copers" and "non-copers" in VO 2 and HR for any gradient. No differences were observed in VE, RER, and VE/VO 2 among the three groups. The walking economy of level, uphill, and downhill walking is reduced in ACL-deficient patients. Despite the improved functional and clinical outcome of "copers", their walking economy appears similar to that of "non-copers" but impaired compared with healthy individuals. The higher energy demand and effort during locomotion in "copers" and "non-copers" has clinical implications for designing safer rehabilitation programmes. The increased energy cost in "copers" may be another parameter to consider when deciding on the most appropriate therapeutic intervention (operative and non-operative), particularly for athletes. II.

Pacing during an ultramarathon running event in hilly terrain

PubMed Central

Cole-Hunter, Tom; Wiegand, Aaron N.; Solomon, Colin

2016-01-01

Purpose The dynamics of speed selection as a function of distance, or pacing, are used in recreational, competitive, and scientific research situations as an indirect measure of the psycho-physiological status of an individual. The purpose of this study was to determine pacing on level, uphill and downhill sections of participants in a long (>80 km) ultramarathon performed on trails in hilly terrain. Methods Fifteen ultramarathon runners competed in a  173 km event (five finished at  103 km) carrying a Global-Positioning System (GPS) device. Using the GPS data, we determined the speed, relative to average total speed, in level (LEV), uphill (UH) and downhill (DH) gradient categories as a function of total distance, as well as the correlation between overall performance and speed variability, speed loss, and total time stopped. Results There were no significant differences in normality, variances or means in the relative speed in 173-km and 103-km participants. Relative speed decreased in LEV, UH and DH. The main component of speed loss occurred between 5% and 50% of the event distance in LEV, and between 5% and 95% in UH and DH. There were no significant correlations between overall performance and speed loss, the variability of speed, or total time stopped. Conclusions Positive pacing was observed at all gradients, with the main component of speed loss occurring earlier (mixed pacing) in LEV compared to UH and DH. A speed reserve (increased speed in the last section) was observed in LEV and UH. The decrease in speed and variability of speed were more important in LEV and DH than in UH. The absence of a significant correlation between overall performance and descriptors of pacing is novel and indicates that pacing in ultramarathons in trails and hilly terrain differs to other types of running events. PMID:27812406

Modeling CO2 degassing and pH in a stream-aquifer system

USGS Publications Warehouse

Choi, J.; Hulseapple, S.M.; Conklin, M.H.; Harvey, J.W.

1998-01-01

Pinal Creek, Arizona receives an inflow of ground water with high dissolved inorganic carbon (57-75 mg/l) and low pH (5.8-6.3). There is an observed increase of in-stream pH from approximately 6.0-7.8 over the 3 km downstream of the point of groundwater inflow. We hypothesized that CO2 gas-exchange was the most important factor causing the pH increase in this stream-aquifer system. An existing transport model, for coupled ground water-surface water systems (OTIS), was modified to include carbonate equilibria and CO2 degassing, used to simulate alkalinity, total dissolved inorganic carbon (C(T)), and pH in Pinal Creek. Because of the non-linear relation between pH and C(T), the modified transport model used the numerical iteration method to solve the non-linearity. The transport model parameters were determined by the injection of two tracers, bromide and propane. The resulting simulations of alkalinity, C(T) and pH reproduced, without fitting, the overall trends in downstream concentrations. A multi-parametric sensitivity analysis (MPSA) was used to identify the relative sensitivities of the predictions to six of the physical and chemical parameters used in the transport model. MPSA results implied that C(T) and pH in stream water were controlled by the mixing of ground water with stream water and CO2 degassing. The relative importance of these two processes varied spatially depending on the hydrologic conditions, such as stream flow velocity and whether a reach gained or lost stream water caused by the interaction with the ground water. The coupled transport model with CO2 degassing and generalized sensitivity analysis presented in this study can be applied to evaluate carbon transport and pH in other coupled stream-ground water systems.An existing transport model for coupled groundwater-surface water systems was modified to include carbonate equilibria and CO2 degassing. The modified model was used to simulate alkalinity, total dissolved inorganic carbon (CT) and pH in Pinal Creek. The model used the numerical iteration method to solve the nonlinear relation between pH and CT. A multi-parametric sensitivity analysis (MPSA) was used to identify the relative sensitivities of the predictions to six of the physical and chemical parameters used in the transport model. MPSA results implied that CT and pH in the stream water were controlled by the mixing of groundwater with stream water and CO2 degassing.

A charge-driven molecular water pump.

PubMed

Gong, Xiaojing; Li, Jingyuan; Lu, Hangjun; Wan, Rongzheng; Li, Jichen; Hu, Jun; Fang, Haiping

2007-11-01

Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications, including the desalination of seawater. Nanopumps driven by electric or magnetic fields can transport ions and magnetic quanta, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient.

Scaling behaviour for the water transport in nanoconfined geometries

PubMed Central

Chiavazzo, Eliodoro; Fasano, Matteo; Asinari, Pietro; Decuzzi, Paolo

2014-01-01

The transport of water in nanoconfined geometries is different from bulk phase and has tremendous implications in nanotechnology and biotechnology. Here molecular dynamics is used to compute the self-diffusion coefficient D of water within nanopores, around nanoparticles, carbon nanotubes and proteins. For almost 60 different cases, D is found to scale linearly with the sole parameter θ as D(θ)=DB[1+(DC/DB−1)θ], with DB and DC the bulk and totally confined diffusion of water, respectively. The parameter θ is primarily influenced by geometry and represents the ratio between the confined and total water volumes. The D(θ) relationship is interpreted within the thermodynamics of supercooled water. As an example, such relationship is shown to accurately predict the relaxometric response of contrast agents for magnetic resonance imaging. The D(θ) relationship can help in interpreting the transport of water molecules under nanoconfined conditions and tailoring nanostructures with precise modulation of water mobility. PMID:24699509

Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic

NASA Astrophysics Data System (ADS)

García-Ibáñez, Maribel I.; Pérez, Fiz F.; Lherminier, Pascale; Zunino, Patricia; Mercier, Herlé; Tréguer, Paul

2018-04-01

We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP) analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW) dominated the upper part of the GEOTRACES-GA01 section. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland-Scotland Overflow Water (ISOW) and North-East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014 OVIDE line (Portugal to Greenland section) by combining the water mass fractions resulting from the eOMP analysis with the absolute geostrophic velocity field estimated through a box inverse model. This allowed us to assess the relative contribution of each water mass to the transport across the section. Finally, we discuss the changes in the distribution and transport of water masses between the 2014 OVIDE line and the 2002-2010 mean state. At the upper and intermediate water levels, colder end-members of the water masses replaced the warmer ones in 2014 with respect to 2002-2010, in agreement with the long-term cooling of the North Atlantic Subpolar Gyre that started in the mid-2000s. Below 2000 dbar, ISOW increased its contribution in 2014 with respect to 2002-2010, with the increase being consistent with other estimates of ISOW transports along 58-59° N. We also observed an increase in SPMW in the East Greenland Irminger Current in 2014 with respect to 2002-2010, which supports the recent deep convection events in the Irminger Sea. From the assessment of the relative water mass contribution to the Atlantic Meridional Overturning Circulation (AMOC) across the OVIDE line, we conclude that the larger AMOC intensity in 2014 compared to the 2002-2010 mean was related to both the increase in the northward transport of Central Waters in the AMOC upper limb and to the increase in the southward flow of Irminger Basin SPMW and ISOW in the AMOC lower limb.

Development and application of the microbial fate and transport module for the Agricultural Policy/Environmental eXtender (APEX) model

NASA Astrophysics Data System (ADS)

Hong, E.; Park, Y.; Muirhead, R.; Jeong, J.; Pachepsky, Y. A.

2017-12-01

Pathogenic microorganisms in recreational and irrigation waters remain the subject of concern. Water quality models are used to estimate microbial quality of water sources, to evaluate microbial contamination-related risks, to guide the microbial water quality monitoring, and to evaluate the effect of agricultural management on the microbial water quality. The Agricultural Policy/Environmental eXtender (APEX) is the watershed-scale water quality model that includes highly detailed representation of agricultural management. The APEX currently does not have microbial fate and transport simulation capabilities. The objective of this work was to develop the first APEX microbial fate and transport module that could use the APEX conceptual model of manure removal together with recently introduced conceptualizations of the in-stream microbial fate and transport. The module utilizes manure erosion rates found in the APEX. Bacteria survival in soil-manure mixing layer was simulated with the two-stage survival model. Individual survival patterns were simulated for each manure application date. Simulated in-stream microbial fate and transport processes included the reach-scale passive release of bacteria with resuspended bottom sediment during high flow events, the transport of bacteria from bottom sediment due to the hyporheic exchange during low flow periods, the deposition with settling sediment, and the two-stage survival. Default parameter values were available from recently published databases. The APEX model with the newly developed microbial fate and transport module was applied to simulate seven years of monitoring data for the Toenepi watershed in New Zealand. Based on calibration and testing results, the APEX with the microbe module reproduced well the monitored pattern of E. coli concentrations at the watershed outlet. The APEX with the microbial fate and transport module will be utilized for predicting microbial quality of water under various agricultural practices, evaluating monitoring protocols, and supporting the selection of management practices based on regulations that rely on fecal indicator bacteria concentrations.

The impacts of water stress on phloem transport in Douglas-fir trees

Treesearch

David Woodruff

2014-01-01

Despite the critical role that phloem plays in a number of plant functional processes and the potential impact of water stress on phloem structural and phloem sap compositional characteristics, little research has been done to examine how water stress influences phloem transport. The objectives of this study were to develop a more accurate understanding of how water...

Structure-function relationships in sapwood water transport and storage.

Treesearch

Barbara L. Gartner; Frederick C. Meinzer

2005-01-01

Primary production by plants requires the loss of substantial quantities of water when the stomata are open for carbon assimilation. The delivery of that water to the leaves occurs through the xylem. The structure, condition, and quantity of the xylem control not only the transport efficiency but also the release of water from storage. For example, if there is high...

Significance of plasmalemma aquaporins for water-transport in Arabidopsis thaliana.

PubMed

Kaldenhoff, R; Grote, K; Zhu, J J; Zimmermann, U

1998-04-01

The plant plasma membrane intrinsic protein, PIP1b, facilitates water transport. These features were characterized in Xenopus oocytes and it has asked whether aquaporins are relevant for water transport in plants. In order to elucidate this uncertainty Arabidopsis thaliana was transformed with an anti-sense construct targeted to the PIP1b gene. Molecular analysis revealed that the anti-sense lines have reduced steady-state levels of PIP1b and the highly homologous PIP1a mRNA. The cell membrane water permeability was analyzed by swelling of protoplasts, which had been transferred into hypotonic conditions. The results indicate that the reduced expression of the specific aquaporins decreases the cellular osmotic water permeability coefficient approximately three times. The morphology and development of the anti-sense lines resembles that of control plants, with the exception of the root system, which is five times as abundant as that of control plants. Xylem pressure measurement suggests that the increase of root mass compensates the reduced cellular water permeability in order to ensure a sufficient water supply to the plant. The results obtained by this study, therefore, clearly demonstrate that aquaporins are important for plant water transport.

Fate and transport of glyphosate and aminomethylphosphonic acid in surface waters of agricultural basins

USGS Publications Warehouse

Gregoire, Caroline; Capel, Paul D.; Coupe, Richard H.; Kalkhoff, Stephen J.

2011-01-01

CONCLUSIONS: Glyphosate use in a watershed results in some occurrence in surface water; however, the watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff and a flow route that does not include transport through the soil.

9 CFR 3.16 - Food and water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Transportation of Dogs and Cats 1 Transportation Standards § 3.16 Food and water requirements. (a) Each dog and... kittens less than 16 weeks of age must be offered food at least once every 12 hours. Each dog and cat must..., exhibitors, research facilities. including Federal research facilities, who transport dogs and cats in their...

Modeling E. Coli release and transport in a creek during artificial high-flow events

USDA-ARS?s Scientific Manuscript database

In-stream fate and transport of E. Coli, is a leading indicator of microbial contamination of natural waters, and so needs to be understood to eventually minimize surface water contamination by microbial organisms. The objective of this work was to simulate E. Coli release and transport from soil se...

9 CFR 3.38 - Food and water requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.38 Food and water requirements. (a) If live guinea pigs or hamsters are to be transported for a period of more than 6 hours, the animals shall..., research facility, exhibitor or operator of an auction sale offering any live guinea pig or hamster to any...

9 CFR 3.16 - Food and water requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Transportation of Dogs and Cats 1 Transportation Standards § 3.16 Food and water requirements. (a) Each dog and... kittens less than 16 weeks of age must be offered food at least once every 12 hours. Each dog and cat must..., exhibitors, research facilities. including Federal research facilities, who transport dogs and cats in their...

Transport of terrigenous polycyclic aromatic hydrocarbons affected by the coastal upwelling in the northwestern coast of South China Sea.

PubMed

Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

2017-10-01

Coastal upwelling prevails in the coast of Hainan Island, the northern South China Sea (SCS) during summer. We studied the influences of the upwelling on the horizontal and vertical transport of terrigenous polycyclic aromatic hydrocarbons (PAHs). PAHs in dissolved and suspended particulate phase of water samples were determined in the upper (depth < 1 m) and water column (depth > 10 m). PAH levels decreased sharply from inshore to offshore to open sea. The results showed that terrestrial input was the main source of coastal PAHs. Perylene, an important indicator of land plant-derived PAH, showed the significant correlation with PAHs (p < 0.005). This implied that fluvial transport was the primary pathway of terrigenous PAHs into the coast of northern SCS. Variations of the concentrations, compositions and diagnostic ratios of PAHs, accompanied the partition equilibrium in the water column, could indicate the selective degradation of PAHs by the plankton affected by upwelling. Different from the "traditional" transport pathway of PAHs in the water column (surface enrichment-depth depletion distribution), the upwelling could provide the original driver to elevate the upward diffusion of sediment entrained contaminants towards the intermediate even the upper waters. It could also enhance the outward diffusion of terrigenous PAHs accompanied by the offshore transport of the upper waters. Therefore, the transport pathway of PAHs can be summarized by the coastal upwelling rising PAHs with their subsequent transport offshore and settling in the adjacent open sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulating contaminant attenuation, double-porosity exchange, and water age in aquifers using MOC3D

USGS Publications Warehouse

Goode, Daniel J.

1999-01-01

MOC3D is a general-purpose computer model developed by the U.S. Geological Survey (USGS) for simulation of three-dimensional solute transport in ground water (Konikow and others, 1996). The model is an update to the widely used USGS two-dimensional solute-transport model (MOC) and is implemented as an optional “package” for the ground-water flow model MODFLOW (Harbaugh and McDonald, 1996). Directly coupling the time-tested MOC transport algorithms with the widely used MODFLOW program makes MOC3D a powerful tool for simulation of solute transport in ground water in many hydrogeologic settings. The model simulates transport processes that include:Advection - Transport of dissolved solutes at the same rate as the average ground-water flow velocity.Diffusion - Spreading of solute from areas of high concentration to areas of low concentration, caused by “random” molecular motionDispersion - Diffusion-like spreading of solute that is caused primarily by spatial variability in aquifer properties, which results in spatial variability in transport velocity.Retardation - Reduction in the apparent solute velocity, compared to the ground-water velocity, caused by linear equilibrium sorption on aquifer materials.Decay - Disappearance of solute caused by reactions such as radioactive decay or biodegradation that are proportional to concentration.Growth - Creation (or disappearance) of solute mass caused by reactions that proceed independent of the solute concentration, such as some cases of biodegradationDouble-porosity exchange - rate-limited exchange of solute mass between mobile and immobile zones; for example, between fractures and the rock matrix.

Greenhouse Gas Emissions Driven by the Transportation of Goods Associated with French Consumption.

PubMed

Hawkins, Troy R; Dente, Sebastien M R

2010-11-15

The transportation of goods plays a significant role in the overall greenhouse gas emissions from consumption. This study investigates the connections between French household consumption and production and transportation-related emissions throughout product supply chains. Here a two-region, environmentally extended input-output model is combined with a novel detailed, physical-unit transportation model to examine the connection between product, location of production, choice of transport mode, and greenhouse gas emissions. Total emissions associated with French household consumption are estimated to be 627 MtCO2e, or 11 tCO2e per capita. Of these, 3% are associated with the transportation of goods within France and 10% with transport of goods outside or into France. We find that most transport originating in northern Europe is by road, whereas most transport from other regions is conducted by sea and ocean transport. Rail, inland water, and air transportation play only a minor role in terms of mass, tonne-kilometers, and greenhouse gas emissions. By product, transport of coal and coke and intermediate goods make the largest contribution to overall freight transport emissions associated with French household consumption. In terms of mass, most goods are transported by road while in terms of tonne-kilometers, sea and ocean transport plays the largest role. Road transport contributes the highest share to the transport of all goods with the exceptions of coal and coke and petroleum. We examine the potential for emissions reductions associated with shifting 10% of direct imports by air freight to sea and ocean or road transport and find that the potential reductions are less than 0.03% of total emissions associated with French consumption. We also consider shifting 10% of direct imports by road transport to rail or inland water and find potential reductions on the order of 0.4−0.5% of the total or 3−4% of the freight transport emissions associated with French consumption. The greatest reductions are achieved by shifting from road transport to rail or inland water for direct imports from northern European countries. This suggests a potential environmental benefit associated with improving rail and inland water infrastructures in Europe.

9 CFR 3.115 - Food and drinking water requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Food and drinking water requirements..., and Transportation of Marine Mammals Transportation Standards § 3.115 Food and drinking water... commerce must be offered food as often as necessary and appropriate for the species involved or as...

9 CFR 3.115 - Food and drinking water requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Food and drinking water requirements..., and Transportation of Marine Mammals Transportation Standards § 3.115 Food and drinking water... commerce must be offered food as often as necessary and appropriate for the species involved or as...

9 CFR 3.115 - Food and drinking water requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Food and drinking water requirements..., and Transportation of Marine Mammals Transportation Standards § 3.115 Food and drinking water... commerce must be offered food as often as necessary and appropriate for the species involved or as...

9 CFR 3.115 - Food and drinking water requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Food and drinking water requirements..., and Transportation of Marine Mammals Transportation Standards § 3.115 Food and drinking water... commerce must be offered food as often as necessary and appropriate for the species involved or as...

MaSTiS, microorganism and solute transport in streams, model documentation and user manual

USDA-ARS?s Scientific Manuscript database

In-stream fate and transport of solutes and microorganisms need to be understood to evaluate suitability of waters for agricultural, recreational, and household uses and eventually minimize surface water contamination. Concerns over safety of this water resulted in development of predictive models f...

Letter from A & R Transport about Section 308 of the Clean Water Act Discharge of Perfluorinated Compounds

EPA Pesticide Factsheets

January 16, 2009 letter from Kenneth E. Pate, VP of Safety and Risk Management of A & R Transport, Inc. to EPA Clean Water Enforcement Branch, about an Information Request about the Section 308 of the Clean Water Act, discharge of pefluorinated compounds.

77 FR 26050 - Burnup Credit in the Criticality Safety Analyses of Pressurized Water Reactor Spent Fuel in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-02

... Pressurized Water Reactor Spent Fuel in Transportation and Storage Casks AGENCY: Nuclear Regulatory Commission... of pressurized water reactor spent nuclear fuel (SNF) in transportation packages and storage casks... for the licensing basis, (b) provide recommendations regarding advanced isotopic depletion and...

Does water transport scale universally with tree size?

Treesearch

F.C. Meinzer; B.J. Bond; J.M. Warren; D.R. Woodruff

2005-01-01

1. We employed standardized measurement techniques and protocols to describe the size dependence of whole-tree water use and cross-sectional area of conducting xylem (sapwood) among several species of angiosperms and conifers. 2. The results were not inconsistent with previously proposed 314-power scaling of water transport with estimated above-...

Transport and transformation of pharmaceuticals and other contaminants of emerging concern from wastewater discharge through surface water to drinking water intake and treatment

EPA Science Inventory

The ubiquitous presence of pharmaceuticals, hormones, and other contaminants of emerging concern (CECs) in surface-water resources have necessitated research that better elucidates pathways of transport and transformation for these compounds from their discharged wastewater, thro...

Flows of bottom water in fractures of the North Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Morozov, E. G.; Tarakanov, R. Yu.; Demidova, T. A.; Makarenko, N. I.

2017-06-01

It has been shown that the total transport of Antarctic Bottom Water (AABW) in the northern fractures (Kane, Cabo Verde, Marathon) are one order of magnitude smaller than in the southern fractures (Vema, Doldrums, Vernadsky). The estimates of AABW transport through this group of fractures based on measurements in 2014 were approximately 0.28 Sv, which is about 25% of the transport through the Vema Fracture Zone. However, the coldest water flows through the Vema Fracture Zone.

Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots1[OPEN

PubMed Central

Durand, Mickaël; Porcheron, Benoît; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

2016-01-01

Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. 14CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. PMID:26802041

Moored observations of the Deep Western Boundary Current in the NW Atlantic: 2004-2014

NASA Astrophysics Data System (ADS)

Toole, John M.; Andres, Magdalena; Le Bras, Isabela A.; Joyce, Terrence M.; McCartney, Michael S.

2017-09-01

A moored array spanning the continental slope southeast of Cape Cod sampled the equatorward-flowing Deep Western Boundary Current (DWBC) for a 10 year period: May 2004 to May 2014. Daily profiles of subinertial velocity, temperature, salinity, and neutral density are constructed for each mooring site and cross-line DWBC transport time series are derived for specified water mass layers. Time-averaged transports based on daily estimates of the flow and density fields in Stream coordinates are contrasted with those derived from the Eulerian-mean flow field, modes of DWBC transport variability are investigated through compositing, and comparisons are made to transport estimates for other latitudes. Integrating the daily velocity estimates over the neutral density range of 27.8-28.125 kg/m3 (encompassing Labrador Sea and Overflow Water layers), a mean equatorward DWBC transport of 22.8 × 106 ± 1.9 × 106 m3/s is obtained. Notably, a statistically significant trend of decreasing equatorward transport is observed in several of the DWBC components as well as the current as a whole. The largest linear change (a 4% decrease per year) is seen in the layer of Labrador Sea Water that was renewed by deep convection in the early 1990s whose transport fell from 9.0 × 106 m3/s at the beginning of the field program to 5.8 × 106 m3/s at its end. The corresponding linear fit to the combined Labrador Sea and Overflow Water DWBC transport decreases from 26.4 × 106 to 19.1 × 106 m3/s. In contrast, no long-term trend is observed in upper ocean Slope Water transport. These trends are discussed in the context of decadal observations of the North Atlantic circulation, and subpolar air-sea interaction/water mass transformation.

How will wind and water erosion change in drylands in the future?

NASA Astrophysics Data System (ADS)

Okin, G. S.; Sala, O.; Vivoni, E. R.

2017-12-01

Drylands are characterized as much by high spatial and temporal variability as they are by low precipitation. Cover that is patchy at multiple scales allows connectivity for wind and water transport. Vegetation dynamics at interannual scales occurs in the context of community change (including woody encroachment) at decadal scales. Periods of drought alternate with relatively wet periods. Future predictions for the world's drylands are that many will become more arid, but near all will experience greater climate variability. This work explores how future variability will affect transport by wind and water, both of which are crucial elements of biotic-abiotic feedbacks that control community change in drylands. This work is based on long-term observations from the Jornada Long Term Ecological Research (LTER), but with lessons that are applicable elsewhere. We find strong relationships between vegetation community, precipitation and aeolian transport related to changes in connectivity. We further identify strong, scale-dependent relationships between precipitation and runoff. Thus, aeolian transport decreases with increasing annual precipitation and transport by water increases with annual precipitation, with the combined effect that increased variability in annual precipitation is likely to increase both water and wind transport. The consequence of this is that feedbacks associated with community change are likely to strengthen in the future.

Insights into the subsurface transport of As(V) and Se(VI) in produced water from hydraulic fracturing using soil samples from Qingshankou Formation, Songliao Basin, China.

PubMed

Chen, Season S; Sun, Yuqing; Tsang, Daniel C W; Graham, Nigel J D; Ok, Yong Sik; Feng, Yujie; Li, Xiang-Dong

2017-04-01

Produced water is a type of wastewater generated from hydraulic fracturing, which may pose a risk to the environment and humans due to its high ionic strength and the presence of elevated concentrations of metals/metalloids that exceed maximum contamination levels. The mobilization of As(V) and Se(VI) in produced water and selected soils from Qingshankou Formation in the Songliao Basin in China were investigated using column experiments and synthetic produced water whose quality was representative of waters arising at different times after well creation. Temporal effects of produced water on metal/metalloid transport and sorption/desorption were investigated by using HYDRUS-1D transport modelling. Rapid breakthrough and long tailings of As(V) and Se(VI) transport were observed in Day 1 and Day 14 solutions, but were reduced in Day 90 solution probably due to the elevated ionic strength. The influence of produced water on the hydrogeological conditions (i.e., change between equilibrium and non-equilibrium transport) was evidenced by the change of tracer breakthrough curves before and after the leaching of produced water. This possibly resulted from the sorption of polyacrylamide (PAM (-CH 2 CHCONH 2 -) n ) onto soil surfaces, through its use as a friction reducer in fracturing solutions. The sorption was found to be reversible in this study. Minimal amounts of sorbed As(V) were desorbed whereas the majority of sorbed Se(VI) was readily leached out, to an extent which varied with the composition of the produced water. These results showed that the mobilization of As(V) and Se(VI) in soil largely depended on the solution pH and ionic strength. Understanding the differences in metal/metalloid transport in produced water is important for proper risk management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methane Bubbles Transport Particles From Contaminated Sediment to a Lake Surface

NASA Astrophysics Data System (ADS)

Delwiche, K.; Hemond, H.

2017-12-01

Methane bubbling from aquatic sediments has long been known to transport carbon to the atmosphere, but new evidence presented here suggests that methane bubbles also transport particulate matter to a lake surface. This transport pathway is of particular importance in lakes with contaminated sediments, as bubble transport could increase human exposure to toxic metals. The Upper Mystic Lake in Arlington, MA has a documented history of methane bubbling and sediment contamination by arsenic and other heavy metals, and we have conducted laboratory and field studies demonstrating that methane bubbles are capable of transporting sediment particles over depths as great as 15 m in Upper Mystic Lake. Methane bubble traps were used in-situ to capture particles adhered to bubble interfaces, and to relate particle mass transport to bubble flux. Laboratory studies were conducted in a custom-made 15 m tall water column to quantify the relationship between water column height and the mass of particulate transport. We then couple this particle transport data with historical estimates of ebullition from Upper Mystic Lake to quantify the significance of bubble-mediated particle transport to heavy metal cycling within the lake. Results suggest that methane bubbles can represent a significant pathway for contaminated sediment to reach surface waters even in relatively deep water bodies. Given the frequent co-occurrence of contaminated sediments and high bubble flux rates, and the potential for human exposure to heavy metals, it will be critical to study the significance of this transport pathway for a range of sediment and contaminant types.

On the development and benchmarking of an approach to model gas transport in fractured media with immobile water storage

NASA Astrophysics Data System (ADS)

Harp, D. R.; Ortiz, J. P.; Pandey, S.; Karra, S.; Viswanathan, H. S.; Stauffer, P. H.; Anderson, D. N.; Bradley, C. R.

2017-12-01

In unsaturated fractured media, the rate of gas transport is much greater than liquid transport in many applications (e.g., soil vapor extraction operations, methane leaks from hydraulic fracking, shallow CO2 transport from geologic sequestration operations, and later-time radionuclide gas transport from underground nuclear explosions). However, the relatively immobile pore water can inhibit or promote gas transport for soluble constituents by providing storage. In scenarios with constant pressure gradients, the gas transport will be retarded. In scenarios with reversing pressure gradients (i.e. barometric pressure variations) pore water storage can enhance gas transport by providing a ratcheting mechanism. Recognizing the computational efficiency that can be gained using a single-phase model and the necessity of considering pore water storage, we develop a Richard's solution approach that includes kinetic dissolution/volatilization of constituents. Henry's Law governs the equilibrium gaseous/aqueous phase partitioning in the approach. The approach is implemented in a development branch of the PFLOTRAN simulator. We verify the approach with analytical solutions of: (1) 1D gas diffusion, (2) 1D gas advection, (3) sinusoidal barometric pumping of a fracture, and (4) gas transport along a fracture with uniform flow and diffusive walls. We demonstrate the retardation of gas transport in cases with constant pressure gradients and the enhancement of gas transport with reversing pressure gradients. The figure presents the verification of our approach to the analytical solution of barometric pumping of a fracture from Nilson et al (1991) where the x-axis "Horizontal axis" is the distance into the matrix block from the fracture.

On the development and benchmarking of an approach to model gas transport in fractured media with immobile water storage

NASA Astrophysics Data System (ADS)

Harp, D. R.; Ortiz, J. P.; Pandey, S.; Karra, S.; Viswanathan, H. S.; Stauffer, P. H.; Anderson, D. N.; Bradley, C. R.

2016-12-01

In unsaturated fractured media, the rate of gas transport is much greater than liquid transport in many applications (e.g., soil vapor extraction operations, methane leaks from hydraulic fracking, shallow CO2 transport from geologic sequestration operations, and later-time radionuclide gas transport from underground nuclear explosions). However, the relatively immobile pore water can inhibit or promote gas transport for soluble constituents by providing storage. In scenarios with constant pressure gradients, the gas transport will be retarded. In scenarios with reversing pressure gradients (i.e. barometric pressure variations) pore water storage can enhance gas transport by providing a ratcheting mechanism. Recognizing the computational efficiency that can be gained using a single-phase model and the necessity of considering pore water storage, we develop a Richard's solution approach that includes kinetic dissolution/volatilization of constituents. Henry's Law governs the equilibrium gaseous/aqueous phase partitioning in the approach. The approach is implemented in a development branch of the PFLOTRAN simulator. We verify the approach with analytical solutions of: (1) 1D gas diffusion, (2) 1D gas advection, (3) sinusoidal barometric pumping of a fracture, and (4) gas transport along a fracture with uniform flow and diffusive walls. We demonstrate the retardation of gas transport in cases with constant pressure gradients and the enhancement of gas transport with reversing pressure gradients. The figure presents the verification of our approach to the analytical solution of barometric pumping of a fracture from Nilson et al (1991) where the x-axis "Horizontal axis" is the distance into the matrix block from the fracture.

Modes of sediment transport in channelized water flows with ramifications to the erosion of the Martian outflow channels

NASA Technical Reports Server (NTRS)

Komar, P. D.

1980-01-01

The paper discusses application to Martian water flows of the criteria that determine which grain-size ranges are transported as bed load, suspension, and wash load. The results show nearly all sand-sized material and finer would have been transported as wash load and that basalt pebbles and even cobbles could have been transported at rapid rates of suspension. An analysis of the threshold of sediment motion on Mars further indicates that the flows would have been highly competent, the larger flows having been able to transport boulder-sized material. Comparisons with terrestrial rivers which transport hyperconcentration levels of sediments suggest that the Martian water flows could have achieved sediment concentrations up to 70% in weight. Although it is possible that flows could have picked up enough sediment to convert to pseudolaminar mud flows, they probably remained at hyperconcentration levels and fully turbulent in flow character.

Cross-shelf transport into nearshore waters due to shoaling internal tides in San Pedro Bay, CA

USGS Publications Warehouse

Noble, Marlene A.; Burt Jones,; Peter Hamilton,; Xu, Jingping; George Robertson,; Rosenfeld, Leslie; John Largier,

2009-01-01

In the summer of 2001, a coastal ocean measurement program in the southeastern portion of San Pedro Bay, CA, was designed and carried out. One aim of the program was to determine the strength and effectiveness of local cross-shelf transport processes. A particular objective was to assess the ability of semidiurnal internal tidal currents to move suspended material a net distance across the shelf. Hence, a dense array of moorings was deployed across the shelf to monitor the transport patterns associated with fluctuations in currents, temperature and salinity. An associated hydrographic program periodically monitored synoptic changes in the spatial patterns of temperature, salinity, nutrients and bacteria. This set of measurements show that a series of energetic internal tides can, but do not always, transport subthermocline water, dissolved and suspended material from the middle of the shelf into the surfzone. Effective cross-shelf transport occurs only when (1) internal tides at the shelf break are strong and (2) subtidal currents flow strongly downcoast. The subtidal downcoast flow causes isotherms to tilt upward toward the coast, which allows energetic, nonlinear internal tidal currents to carry subthermocline waters into the surfzone. During these events, which may last for several days, the transported water remains in the surfzone until the internal tidal current pulses and/or the downcoast subtidal currents disappear. This nonlinear internal tide cross-shelf transport process was capable of carrying water and the associated suspended or dissolved material from the mid-shelf into the surfzone, but there were no observation of transport from the shelf break into the surfzone. Dissolved nutrients and suspended particulates (such as phytoplankton) transported from the mid-shelf into the nearshore region by nonlinear internal tides may contribute to nearshore algal blooms, including harmful algal blooms that occur off local beaches.

Reactive solute transport in streams: 1. Development of an equilibrium- based model

USGS Publications Warehouse

Runkel, Robert L.; Bencala, Kenneth E.; Broshears, Robert E.; Chapra, Steven C.

1996-01-01

An equilibrium-based solute transport model is developed for the simulation of trace metal fate and transport in streams. The model is formed by coupling a solute transport model with a chemical equilibrium submodel based on MINTEQ. The solute transport model considers the physical processes of advection, dispersion, lateral inflow, and transient storage, while the equilibrium submodel considers the speciation and complexation of aqueous species, precipitation/dissolution and sorption. Within the model, reactions in the water column may result in the formation of solid phases (precipitates and sorbed species) that are subject to downstream transport and settling processes. Solid phases on the streambed may also interact with the water column through dissolution and sorption/desorption reactions. Consideration of both mobile (water-borne) and immobile (streambed) solid phases requires a unique set of governing differential equations and solution techniques that are developed herein. The partial differential equations describing physical transport and the algebraic equations describing chemical equilibria are coupled using the sequential iteration approach.

Investigating water transport through the xylem network in vascular plants.

PubMed

Kim, Hae Koo; Park, Joonghyuk; Hwang, Ildoo

2014-04-01

Our understanding of physical and physiological mechanisms depends on the development of advanced technologies and tools to prove or re-evaluate established theories, and test new hypotheses. Water flow in land plants is a fascinating phenomenon, a vital component of the water cycle, and essential for life on Earth. The cohesion-tension theory (CTT), formulated more than a century ago and based on the physical properties of water, laid the foundation for our understanding of water transport in vascular plants. Numerous experimental tools have since been developed to evaluate various aspects of the CTT, such as the existence of negative hydrostatic pressure. This review focuses on the evolution of the experimental methods used to study water transport in plants, and summarizes the different ways to investigate the diversity of the xylem network structure and sap flow dynamics in various species. As water transport is documented at different scales, from the level of single conduits to entire plants, it is critical that new results be subjected to systematic cross-validation and that findings based on different organs be integrated at the whole-plant level. We also discuss the functional trade-offs between optimizing hydraulic efficiency and maintaining the safety of the entire transport system. Furthermore, we evaluate future directions in sap flow research and highlight the importance of integrating the combined effects of various levels of hydraulic regulation.

A regional modeling framework of phosphorus sources and transport in streams of the southeastern United States

USGS Publications Warehouse

Garcia, Ana Maria.; Hoos, Anne B.; Terziotti, Silvia

2011-01-01

We applied the SPARROW model to estimate phosphorus transport from catchments to stream reaches and subsequent delivery to major receiving water bodies in the Southeastern United States (U.S.). We show that six source variables and five land-to-water transport variables are significant (p < 0.05) in explaining 67% of the variability in long-term log-transformed mean annual phosphorus yields. Three land-to-water variables are a subset of landscape characteristics that have been used as transport factors in phosphorus indices developed by state agencies and are identified through experimental research as influencing land-to-water phosphorus transport at field and plot scales. Two land-to-water variables – soil organic matter and soil pH – are associated with phosphorus sorption, a significant finding given that most state-developed phosphorus indices do not explicitly contain variables for sorption processes. Our findings for Southeastern U.S. streams emphasize the importance of accounting for phosphorus present in the soil profile to predict attainable instream water quality. Regional estimates of phosphorus associated with soil-parent rock were highly significant in explaining instream phosphorus yield variability. Model predictions associate 31% of phosphorus delivered to receiving water bodies to geology and the highest total phosphorus yields in the Southeast were catchments with already high background levels that have been impacted by human activity.

A Regional Modeling Framework of Phosphorus Sources and Transport in Streams of the Southeastern United States

USGS Publications Warehouse

Garcia, A.M.; Hoos, A.B.; Terziotti, S.

2011-01-01

We applied the SPARROW model to estimate phosphorus transport from catchments to stream reaches and subsequent delivery to major receiving water bodies in the Southeastern United States (U.S.). We show that six source variables and five land-to-water transport variables are significant (p<0.05) in explaining 67% of the variability in long-term log-transformed mean annual phosphorus yields. Three land-to-water variables are a subset of landscape characteristics that have been used as transport factors in phosphorus indices developed by state agencies and are identified through experimental research as influencing land-to-water phosphorus transport at field and plot scales. Two land-to-water variables - soil organic matter and soil pH - are associated with phosphorus sorption, a significant finding given that most state-developed phosphorus indices do not explicitly contain variables for sorption processes. Our findings for Southeastern U.S. streams emphasize the importance of accounting for phosphorus present in the soil profile to predict attainable instream water quality. Regional estimates of phosphorus associated with soil-parent rock were highly significant in explaining instream phosphorus yield variability. Model predictions associate 31% of phosphorus delivered to receiving water bodies to geology and the highest total phosphorus yields in the Southeast were catchments with already high background levels that have been impacted by human activity. ?? 2011 American Water Resources Association. This article is a US Government work and is in the public domain in the USA.

Hydrology of the Bonneville Salt Flats, northwestern Utah, and simulation of ground-water flow and solute transport in the shallow-brine aquifer

USGS Publications Warehouse

Mason, James L.; Kipp, Kenneth L.

1998-01-01

This report describes the hydrologic system of the Bonneville Salt Flats with emphasis on the mechanisms of solute transport. Variable-density, three-dimensional computer simulations of the near-surface part of the ground-water system were done to quantify both the transport of salt dissolved in subsurface brine that leaves the salt-crust area and the salt dissolved and precipitated on the land surface. The study was designed to define the hydrology of the brine ground-water system and the natural and anthropogenic processes causing salt loss, and where feasible, to quantify these processes. Specific areas of study include the transport of salt in solution by ground-water flow and the transport of salt in solution by wind-driven ponds and the subsequent salt precipitation on the surface of the playa upon evaporation or seepage into the subsurface. In addition, hydraulic and chemical changes in the hydrologic system since previous studies were documented.

Canary Current and North Equatorial Current from an inverse box model

NASA Astrophysics Data System (ADS)

HernáNdez-Guerra, Alonso; Fraile-Nuez, Eugenio; López-Laatzen, Federico; MartíNez, Antonio; Parrilla, Gregorio; VéLez-Belchí, Pedro

2005-12-01

The large-scale Canary Basin circulation is estimated from a box inverse model applied to hydrographic data from a quasi-synoptic survey carried out in September 2003. The cruise consisted of 76 full depth CTD and oxygen stations. Circulation is required to nearly conserve mass and anomalies of salinity and heat within layers bounded by neutral surfaces. It permits advective and diffusive exchange between layers and an adjustment of the Ekman transport and the freshwater flux divergences. The Canary Current at the thermocline layer transports a net mass of 4.7 ± 0.8 Sv southward north of the Canary Islands from the African coast to 19°W. It is divided into a northward circulation at a rate of 1.1 ± 0.5 Sv between the African coast and Lanzarote Island and a southward transport of 5.8 ± 0.6 Sv. It transports North Atlantic Central Water and organic matters advected offshore by the filaments protruding from the upwelling system off northwest Africa. At 24°N, the Canary Current feeds the North Equatorial Current that transports a mixture of North and South Atlantic Central Waters westward. In the intermediate layer a southwestward flow of 1.2 ± 1.1 Sv transports Mediterranean Water to the Subtropical Gyre, though the highest salt flux is transported by a meddy. Oxygen distribution and mass transport suggest a northeastward deep flow of a water mass colder than 2.2°C consisting of diluted Antarctic Bottom Water. The heat and freshwater divergences and the average dianeutral velocity and diffusion between the sections and the African coast are negligible.

Axial and radial water transport and internal water storage in tropical forest canopy trees.

Treesearch

Shelley A. James; Frederick C. Meinzer; Guillermo Goldstein; David Woodruff; Timothy Jones; Teresa Restom; Monica Mejia; Michael Clearwater; Paula Campanello

2003-01-01

Heat and stable isotope tracers were used to study axial and radial water transport in relation to sapwood anatomical characteristics and internal water storage in four canopy tree species of a seasonally dry tropical forest in Panama. Anatomical characteristics of the wood and radial profiles of sap flow were measured at the base, upper trunk, and crown of a single...

A New Scheme for Considering Soil Water-Heat Transport Coupling Based on Community Land Model: Model Description and Preliminary Validation

NASA Astrophysics Data System (ADS)

Wang, Chenghai; Yang, Kai

2018-04-01

Land surface models (LSMs) have developed significantly over the past few decades, with the result that most LSMs can generally reproduce the characteristics of the land surface. However, LSMs fail to reproduce some details of soil water and heat transport during seasonal transition periods because they neglect the effects of interactions between water movement and heat transfer in the soil. Such effects are critical for a complete understanding of water-heat transport within a soil thermohydraulic regime. In this study, a fully coupled water-heat transport scheme (FCS) is incorporated into the Community Land Model (version 4.5) to replaces its original isothermal scheme, which is more complete in theory. Observational data from five sites are used to validate the performance of the FCS. The simulation results at both single-point and global scale show that the FCS improved the simulation of soil moisture and temperature. FCS better reproduced the characteristics of drier and colder surface layers in arid regions by considering the diffusion of soil water vapor, which is a nonnegligible process in soil, especially for soil surface layers, while its effects in cold regions are generally inverse. It also accounted for the sensible heat fluxes caused by liquid water flow, which can contribute to heat transfer in both surface and deep layers. The FCS affects the estimation of surface sensible heat (SH) and latent heat (LH) and provides the details of soil heat and water transportation, which benefits to understand the inner physical process of soil water-heat migration.

Ion pump as Brownian motor: theory of electroconformational coupling and proof of ratchet mechanism for Na,K-ATPase action

NASA Astrophysics Data System (ADS)

Tsong, Tian Yow; Chang, Cheng-Hung

2003-04-01

This article reviews some concepts of the Brownian Ratchet which are relevant to our discussion of mechanisms of action of Na,K-ATPase, a universal ion pump and an elemental motor protein of the biological cell. Under wide ranges of ionic compositions it can hydrolyze an ATP and use the γ-phosphorous bond energy of ATP to pump 3 Na + out of, and 2 K + into the cell, both being uphill transport. During the ATP-dependent pump cycle, the enzyme oscillates between E1 and E2 states. Our experiment replaces ATP with externally applied electric field of various waveforms, amplitudes, and frequencies. The field enforced-oscillation, or fluctuation of E1 and E2 states enables the enzyme to harvest energy from the applied field and convert it to the chemical gradient energy of cations. A theory of electroconformational coupling (TEC), which embodies all the essential features of the Brownian Ratchet, successfully simulates these experimental results. Our analysis based on a four-state TEC model indicates that the equilibrium and the rate constants of the transport system define the frequency and the amplitude of the field for the optimal activation. Waveform, frequency, and amplitude are three elements of signal. Thus, electric signal of the ion pump is found by TEC analysis of the experimental data. Electric noise (white) superimposed on an electric signal changes the pump efficiency and produces effects similar to the stochastic resonance reported in other biological systems. The TEC concept is compared with the most commonly used Michaelis-Menten enzyme mechanism (MME) for similarities and differences. Both MME and TEC are catalytic wheels, which recycle the catalyst in each turnover. However, a MME can only catalyze reaction of descending free energy while a TEC enzyme can catalyze reaction of ascending free energy by harvesting needed energy from an off-equilibrium electric noise. The TEC mechanism is shown to be applicable to other biological motors and engines, as well. Deterministic and non-deterministic noise is examined in reference to future extension of the TEC model for biological transduction of free energy.

The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

NASA Technical Reports Server (NTRS)

Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

2014-01-01

We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

Characteristics of photosynthesis and functions of the water-water cycle in rice (Oryza sativa) leaves in response to potassium deficiency.

PubMed

Weng, Xiao-Yan; Zheng, Chen-Juan; Xu, Hong-Xia; Sun, Jian-Yi

2007-12-01

The mechanisms of photoprotection of photosynthesis and dissipation of excitation energy in rice leaves in response to potassium (K) deficiency were investigated. Net photosynthetic rate and the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase decreased under K deficiency. Compared with the control, non-photochemical quenching of Chl fluorescence increased in K-deficient plant, whereas the efficiency of excitation transfer (F'(v)/F'(m)) and the photochemical quenching coefficient (q(P)) decreased. Thus, thermal dissipation of excitation energy increased as more excess electrons were accumulated in the photosynthetic chain. The electron transport rate through PSII (J(f)) was more sensitive to O2 concentration, and the fraction of electron transport rate required to sustain CO2 assimilation and photorespiration (J(g)/J(f)) was significantly decreased under K deficiency compared with the control. Furthermore, the alternative electron transport (J(a)/J(f)) was increased, indicating that a considerable amount of electrons had been transported to O2 during the water-water cycle in the K-deficient leaves. Although the fraction of electron transport to photorespiration (J(o)/J(f)) was also increased in the K-deficient leaves, it was less sensitive than that of the water-water cycle. With the generation of reactive oxygen species level, the activities of superoxide dismutase and ascorbate peroxidase, two of the key enzymes involved in scavenging of active oxygen species in the water-water cycle, also increased in K-deficient rice. Therefore, it is likely that a series of photoprotective mechanisms were initiated in rice plants in response to K deficiency and the water-water cycle might be critical for protecting photosynthetic apparatus under K deficiency in rice.

Spacebased Observation of Water Balance Over Global Oceans

NASA Astrophysics Data System (ADS)

Liu, W.; Xie, X.

2008-12-01

We demonstrated that ocean surface fresh water flux less the water discharge into the ocean from river and ice melt balances the mass loss in the ocean both in magnitude and in the phase of annual variation. The surface water flux was computed from the divergence of the water transport integrated over the depth of the atmosphere. The atmospheric water transport is estimated from the precipitable water measured by Special Sensor Microwave Imager, the surface wind vector by QuikSCAT, and the NOAA cloud drift wind through a statistical model. The transport has been extensively validated using global radiosonde and data and operational numerical weather prediction results. Its divergence has been shown to agree with the difference between evaporation estimated from the Advanced Microwave Scanning Radiometer data and the precipitation measured by Tropical Rain Measuring Mission over the global tropical and subtropical oceans both in magnitude and geographical distribution for temporal scales ranging from intraseasonal to interannual. The water loss rate in the ocean is estimated by two methods, one is from Gravity Recovery and Climate Experiment and the other is by subtracting the climatological steric change from the sea level change measured by radar altimeter on Jason. Only climatological river discharge and ice melt from in situ measurements are available and the lack of temporal variation may contribute to discrepancies in the balance. We have successfully used the spacebased surface fluxes to estimate to climatological mean heat transport in the Atlantic ocean and is attempting to estimate the meridional fresh water (or salt) transport from the surface flux. The approximate closure of the water balance gives a powerful indirect validation of the spacebased products.

Probabilistic cost estimation methods for treatment of water extracted during CO 2 storage and EOR

DOE PAGES

Graham, Enid J. Sullivan; Chu, Shaoping; Pawar, Rajesh J.

2015-08-08

Extraction and treatment of in situ water can minimize risk for large-scale CO 2 injection in saline aquifers during carbon capture, utilization, and storage (CCUS), and for enhanced oil recovery (EOR). Additionally, treatment and reuse of oil and gas produced waters for hydraulic fracturing will conserve scarce fresh-water resources. Each treatment step, including transportation and waste disposal, generates economic and engineering challenges and risks; these steps should be factored into a comprehensive assessment. We expand the water treatment model (WTM) coupled within the sequestration system model CO 2-PENS and use chemistry data from seawater and proposed injection sites in Wyoming,more » to demonstrate the relative importance of different water types on costs, including little-studied effects of organic pretreatment and transportation. We compare the WTM with an engineering water treatment model, utilizing energy costs and transportation costs. Specific energy costs for treatment of Madison Formation brackish and saline base cases and for seawater compared closely between the two models, with moderate differences for scenarios incorporating energy recovery. Transportation costs corresponded for all but low flow scenarios (<5000 m 3/d). Some processes that have high costs (e.g., truck transportation) do not contribute the most variance to overall costs. Other factors, including feed-water temperature and water storage costs, are more significant contributors to variance. These results imply that the WTM can provide good estimates of treatment and related process costs (AACEI equivalent level 5, concept screening, or level 4, study or feasibility), and the complex relationships between processes when extracted waters are evaluated for use during CCUS and EOR site development.« less

Mysterious Roving Rocks of Racetrack Playa

NASA Image and Video Library

2017-12-08

A small level is used to see if the trail is tilted upward or downward. In most cases where a rock has moved, the trail is tilted very slightly uphill, but the interns don't think this has a noticeable effect on the movement. The compass is included for scale. Photo credit: NASA/GSFC/Leva McIntire/LPSA intern To read a feature story on the Racetrack Playa go to: www.nasa.gov/topics/earth/features/roving-rocks.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Autonomous hip exoskeleton saves metabolic cost of walking uphill.

PubMed

Seo, Keehong; Lee, Jusuk; Park, Young Jin

2017-07-01

We have developed a hip joint exoskeleton to boost gait function in the elderly and rehabilitation of post-stroke patients. To quantitatively evaluate the impact of the power and mass of the exoskeleton, we measured the metabolic cost of walking on slopes of 0, 5, and 10% grade, once not wearing the exoskeleton and then wearing it. The exoskeleton reduced the metabolic cost by 13.5,15.5 and 9.8% (31.9, 51.6 and 45.6 W) at 0, 5, and 10% grade, respectively. The exoskeleton performance index was computed as 0.97, 1.24, and 1.24 at each grade, implicating that the hip exoskeleton was more effective on slopes than level ground in saving the metabolic cost.

THE IMPACT OF GROUND WATER-SURFACE WATER INTERACTIONS ON CONTAMINANT TRANSPORT AT CONTAMINATED SITES

EPA Science Inventory

The purpose of this document is to provide an overview of the dynamics of chemical processes that govern contaminant transport and speciation during water exchange across the GW/SW transition zone. A conceptual model of the GW/SW transition zone is defined to serve as a starting...

7 CFR 319.8-10 - Covers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... movement shall be made by an all-water route unless the bales are compressed to a density of 20 pounds or...-water transportation is not available. Such overland movement may be made only after approved surface... be required to be transported therefrom immediately in bond by an all-water route to a northern or...

Models of Fate and Transport of Pollutants in Surface Waters

ERIC Educational Resources Information Center

Okome, Gloria Eloho

2013-01-01

There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…