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Sample records for cycles age effects

  1. Effect of cycled combustion ageing on a cordierite burner plate

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Eugenio [Instituto de Ceramica y Vidrio, CSIC, c/ Kelsen 5, Campus de Cantoblanco, 28049 Madrid (Spain); Gancedo, J. Ramon [Instituto de Quimica Fisica ' Rocasolano' , CSIC, c/ Serrano 119, 28006 Madrid (Spain); Gracia, Mercedes, E-mail: rocgracia@iqfr.csic.es [Instituto de Quimica Fisica ' Rocasolano' , CSIC, c/ Serrano 119, 28006 Madrid (Spain)

    2010-11-15

    A combination of {sup 57}Fe-Moessbauer spectroscopy and X-ray Powder Diffraction analysis has been employed to study modifications in chemical and mechanical stability occurring in a cordierite burner aged under combustion conditions which simulate the working of domestic boilers. Moessbauer study shows that Fe is distributed into the structural sites of the cordierite lattice as Fe{sup 2+} and Fe{sup 3+} ions located mostly at octahedral sites. Ferric oxide impurities, mainly hematite, are also present in the starting cordierite material accounting for {approx_equal}40% of the total iron phases. From Moessbauer and X-ray diffraction data it can be deduced that, under the combustion conditions used, new crystalline phases were formed, some of the substitutional Fe{sup 3+} ions existing in the cordierite lattice were reduced to Fe{sup 2+}, and ferric oxides underwent a sintering process which results in hematite with higher particle size. All these findings were detected in the burner zone located in the proximity of the flame and were related to possible chemical reactions which might explain the observed deterioration of the burner material. Research Highlights: {yields}Depth profile analyses used as a probe to understand changes in refractory structure. {yields}All changes take place in the uppermost surface of the burner, close to the flame. {yields}Reduction to Fe{sup 2+} of substitutional Fe{sup 3+} ions and partial cordierite decomposition. {yields}Heating-cooling cycling induces a sintering of the existing iron oxide particles. {yields}Chemical changes can explain the alterations observed in the material microstructure.

  2. Effect of dynamic strain aging on isotropic hardening in low cycle fatigue for carbon manganese steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhi Yong, E-mail: huangzy@scu.edu.cn [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Chaboche, Jean-Louis [ONERA, DMSM, 29 avenue de la Division Lecerc, F-92320 Chatillon (France); Wang, Qing Yuan [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle; Bathias, Claude [Université ParisOuest Nanterre La Défense (France)

    2014-01-01

    Carbon–manganese steel A48 (French standard) is used in steam generator pipes of nuclear reactor pressure vessels at high temperatures (about 200 °C). The steel is sensitive to dynamic strain aging in monotonic tensile test and low cycle fatigue test at certain temperature range and strain rate. Its isotropic hardening behavior observed from experiments has a hardening, softening and hardening evolution with the effect of dynamic strain aging. The isotropic hardening model is improved by coupling the dislocation and dynamic strain aging theory to describe the behavior of A48 at 200 °C.

  3. Effects of aging and training status on ventilatory response during incremental cycling exercise.

    Science.gov (United States)

    Lenti, Mauro; De Vito, Giuseppe; Scotto di Palumbo, Alessandro; Sbriccoli, Paola; Quattrini, Filippo M; Sacchetti, Massimo

    2011-05-01

    The aim of this study was to examine the effect of aging and training status on ventilatory response during incremental cycling exercise. Eight young (24 ± 5 years) and 8 older (64 ± 3 years) competitive cyclists together with 8 young (27 ± 4 years) and 8 older (63 ± 2 years) untrained individuals underwent a continuous incremental cycling test to exhaustion to determine ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen uptake (VO₂max). In addition, the isocapnic buffering (IB) phase was calculated together with the hypocapnic hyperventilation. Ventilatory threshold occurred at similar relative exercise intensities in all groups, whereas RCP was recorded at higher intensities in young and older cyclists compared to the untrained subjects. The IB phase, reported as the difference between VT and RCP and expressed either in absolute (ml·min⁻¹·kg⁻¹ VO₂) or in relative terms, was greater (p < 0.01) in both young and older trained cyclists than in untrained subjects, who were also characterized by a lower exercise capacity. Isocapnic buffering was particularly small in the older untrained volunteers. Although young untrained and older trained subjects had a similar level of VO₂max, older athletes exhibited a larger IB. In addition, a higher absolute but similar relative IB was observed in young vs. older cyclists, despite a higher VO₂max in the former. In conclusion, the present study shows that aging is associated with a reduction of the IB phase recorded during an incremental exercise test. Moreover, endurance training induces adaptations that result in an enlargement of the IB phase independent of age. This information can be used for the characterization and monitoring of the physiological adaptations induced by endurance training.

  4. Effects of creatine loading on electromyographic fatigue threshold during cycle ergometry in college-aged women

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    Cramer Joel T

    2007-11-01

    Full Text Available Abstract The purpose of this study was to examine the effects of 5 days of Creatine (Cr loading on the electromyographic fatigue threshold (EMGFT in college-aged women. Fifteen healthy college-aged women (mean ± SD = 22.3 ± 1.7 yrs volunteered to participate in this double-blind, placebo-controlled study and were randomly placed into either placebo (PL – 10 g of flavored dextrose powder; n = 8 or creatine (Cr – 5 g di-creatine citrate plus 10 g of flavored dextrose powder; n = 7; Creatine Edge, FSI Nutrition loading groups. Each group ingested one packet 4 times per day (total of 20 g/day for 5 days. Prior to and following supplementation, each subject performed a discontinuous incremental cycle ergometer test to determine their EMGFT value, using bipolar surface electrodes placed on the longitudinal axis of the right vastus lateralis. Subjects completed a total of four, 60 second work bouts (ranging from 100–350 W. The EMG amplitude was averaged over 10 second intervals and plotted over the 60 second work bout. The resulting slopes from each successive work bouts were used to calculate EMGFT. A two-way ANOVA (group [Cr vs. PL] × time [pre vs. post] resulted in a significant (p = 0.031 interaction. Furthermore, a dependent samples t-test showed a 14.5% ± 3.5% increase in EMGFT from pre- to post-supplementation with Cr (p = 0.009, but no change for the PL treatment (-2.2 ± 5.8%; p = 0.732. In addition, a significant increase (1.0 ± 0.34 kg; p = 0.049 in weight (kg was observed in the Cr group but no change for PL (-0.2 kg ± 0.2 kg. These findings suggest that 5 days of Cr loading in women may be an effective strategy for delaying the onset of neuromuscular fatigue during cycle ergometry.

  5. Response of tibialis anterior tendon to a chronic exposure of stretch-shortening cycles: age effects

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    Baker Brent B

    2009-06-01

    Full Text Available Abstract Background The purpose of the current study was to investigate the effects of aging on tendon response to repetitive exposures of stretch-shortening cycles (SSC's. Methods The left hind limb from young (3 mo, N = 4 and old (30 mo, N = 9 male Fisher 344 × Brown Norway rats were exposed to 80 maximal SSCs (60 deg/s, 50 deg range of motion 3x/week for 4.5 weeks in vivo. After the last exposure, tendons from the tibialis anterior muscle were isolated, stored at -80°C, and then tested using a micro-mechanical testing machine. Deformation of each tendon was evaluated using both relative grip-to-grip displacements and reference marks via a video system. Results At failure, the young control tendons had higher strain magnitude than the young exposed (p Conclusion The chronic protocol enhanced the elastic stiffness of young tendon and the loads in both the young and old tendons. The old exposed tendons were found to exhibit higher load capacity than their younger counterparts, which differed from our initial hypothesis.

  6. Improved effectiveness of artificial insemination of turkey hens associated with ahemeral light-dark cycles and age at photostimulation.

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    Siopes, T D

    1999-06-01

    In lighting studies with turkey hens, long ahemeral (AH; non-24 h) light-dark cycles have consistently resulted in greater, although not statistically significant, fertility than control 24 h light-dark cycles. The present study was designed to further evaluate AH lighting effects on fertility by an evaluation of the effectiveness of artificial insemination (AI) under less than optimal conditions for normal fertility, that is, single AI and early age at lighting. Turkey hens had greater percentage fertility of eggs when photostimulated at 30 wk (95.0) than 26 wk (76.3) of age following single, but not double, AI. Ahemeral lighting dramatically improved the effectiveness of a single AI of hens photostimulated at 26 wk of age as compared to controls (89.3 vs 76.3% fertility, respectively). However, with multiple AI, benefits of AH lighting on fertility exceeding that of control hens was not significant. It may be concluded that AH lighting can dramatically improve the effectiveness of AI under certain adverse conditions, such as early age at lighting and reduced exposure of the hen to sperm.

  7. Effect of Gaseous Impurities on Long-Term Thermal Cycling and Aging Properties of Complex Hydrides for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Dhanesh [Primary Contact; Lamb, Joshua; Chien, Wen-Ming; Talekar, Anjali; and Pal, Narendra

    2011-03-28

    This program was dedicated to understanding the effect of impurities on Long-Term Thermal Cycling and aging properties of Complex Hydrides for Hydrogen Storage. At the start of the program we found reversibility between Li2NH+LiH LiH+LiNH2 (yielding ~5.8 wt.%H capacity). Then we tested the effect of impurity in H2 gas by pressure cycling at 255°C; first with industrial gas containing ppm levels of O2 and H2O as major impurities. Both these impurities had a significant impact on the reversibility and decreased the capacity by 2.65 wt.%H. Further increase in number of cycles from 500 to 1100 showed only a 0.2 wt%H more weight loss, showing some capacity is still maintained after a significant number of cycles. The loss of capacity is attributed to the formation of ~55 wt% LiH and ~30% Li2O, as major contaminant phases, along with the hydride Li2NH phase; suggesting loss of nitrogen during cycling. The effect of 100 ppm H2O in H2 also showed a decrease of ~2.5 wt.%H (after 560 cycles), and 100ppm O2 in H2; a loss of ~4.1 wt.%. Methane impurity (100 ppm, 100cycles), showed a very small capacity loss of 0.9 wt.%H under similar conditions. However, when Li3N was pressure cycled with 100ppmN2-H2 there were beneficial effects were observed (255oC); the reversible capacity increased to 8.4wt.%H after 853 cycles. Furthermore, with 20 mol.%N2-H2 capacity increased to ~10 wt.%H after 516 cycles. We attribute this enhancement to the reaction of nitrogen with liquid lithium during cycling as the Gibbs free energy of formation of Li3N (Go = -98.7 kJ/mol) is more negative than that of LiH (Go = -50.3 kJ/mol). We propose that the mitigation of hydrogen capacity losses is due to the destabilization of the LiH phase that tends to accumulate during cycling. Also more Li2NH phase was found in the cycled product. Mixed Alanates (3LiNH2:Li3AlH6) showed that 7 wt% hydrogen desorbed under dynamic vacuum. Equilibrium experiments (maximum 12 bar H2) showed up to 4wt% hydrogen reversibly

  8. A low cycle fatigue model for low carbon manganese steel including the effect of dynamic strain aging

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    Huang, Zhi Yong, E-mail: huangzy@scu.edu.cn [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle [Université Paris Ouest Nanterre La Défense (France); Wang, Qing Yuan; Khan, Muhammad Kashif [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Chaboche, Jean–Louis [ONERA, DMSM, 29 avenue de la Division Lecerc, F-92320, Chatillon (France)

    2016-01-27

    Carbon–manganese steel A48 (French standards) is used in steam generator pipes of the nuclear power plant where it is subjected to the cyclic thermal load. The Dynamic Strain Aging (DSA) influences the mechanical behavior of the steel in low cycle fatigue (LCF) at favorable temperature and strain rate. The peak stress of A48 steel experiences hardening–softening–hardening (HSH) evolution at 200 °C and 0.4% s{sup −1} strain rate in fatigue loading. In this study, isotropic and kinematic hardening rules with DSA effect have been modified. The HSH evolution of cyclic stress associated with cumulative plastic deformation has also been estimated.

  9. Acute effects of a thermogenic nutritional supplement on cycling time to exhaustion and muscular strength in college-aged men

    Directory of Open Access Journals (Sweden)

    Beck Travis W

    2009-07-01

    Full Text Available Abstract Background The purpose of the present study was to examine the acute effects of a thermogenic nutritional supplement containing caffeine, capsaicin, bioperine, and niacin on muscular strength and endurance performance. Methods Twenty recreationally-active men (mean ± SD age = 21.5 ± 1.4 years; stature = 178.2 ± 6.3 cm; mass = 76.5 ± 9.9 kg; VO2 PEAK = 3.05 ± 0.59 L/min-1 volunteered to participate in this randomized, double-blinded, placebo-controlled, cross-over study. All testing took place over a three-week period, with each of the 3 laboratory visits separated by 7 days (± 2 hours. During the initial visit, a graded exercise test was performed on a Lode Corival cycle ergometer (Lode, Groningen, Netherlands until exhaustion (increase of 25 W every 2 min to determine the maximum power output (W at the VO2 PEAK (Parvo Medics TrueOne® 2400 Metabolic Measurement System, Sandy, Utah. In addition, one-repetition maximum (1-RM strength was assessed using the bench press (BP and leg press (LP exercises. During visits 2 and 3, the subjects were asked to consume a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin or the placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule 30 min prior to the testing. Testing included a time-to-exhaustion (TTE ride on a cycle ergometer at 80% of the previously-determined power output at VO2 PEAK followed by 1-RM LP and BP tests. Results There were no differences (p > 0.05 between the active and placebo trials for BP, LP, or TTE. However, for the BP and LP scores, the baseline values (visit 1 were less than the values recorded during visits 2 and 3 (p ≤ 0.05. Conclusion Our findings indicated that the active supplement containing caffeine, capsaicin, bioperine, and niacin did not alter muscular strength or cycling endurance when compared

  10. Ageing effects on knee and ankle joint angles at key events and phases of the gait cycle.

    Science.gov (United States)

    Begg, R K; Sparrow, W A

    2006-01-01

    The objective of this research was to determine whether joint angles at critical gait events and during major energy generation/absorption phases of the gait cycle would reliably discriminate age-related degeneration during unobstructed walking. The gaits of 24 healthy adults (12 young and 12 elderly) were analysed using the PEAK Motus motion analysis system. The elderly participants showed significantly greater single (60.3% versus 62.3%, p phase. The plantarflexing ankle joint motion during the stance to swing phase transition (A2) for the young group (31.3 degrees ) was about twice ( p gait to assist in weight acceptance. Reduced dorsiflexion by the elderly in the swing phase implies greater risk of toe contact with obstacles. Overall, the results suggest that joint angle measures at critical events/phases in the gait cycle provide a useful indication of age-related degeneration in the control of lower limb trajectories during unobstructed walking.

  11. Pseudoelastic cycling and ageing effects at ambient temperature in nanocrystalline Ni-rich NiTi wire

    Energy Technology Data Exchange (ETDEWEB)

    Yawny, A. [Centro Atomico Bariloche, CNEA and CONICET, 8400 S.C. de Bariloche (Argentina)], E-mail: yawny@cab.cnea.gov.ar; Olbricht, J. [Ruhr-Universitaet Bochum, Institut fuer Werkstoffe, 44780 Bochum (Germany); Sade, M. [Centro Atomico Bariloche, CNEA and CONICET, 8400 S.C. de Bariloche (Argentina); Eggeler, G. [Ruhr-Universitaet Bochum, Institut fuer Werkstoffe, 44780 Bochum (Germany)

    2008-05-25

    It is well known how the features of a stress-strain hysteresis during pseudoelastic pull-pull cycling of NiTi evolve: plateau stresses for the forward (loading) and reverse transformation (unloading) decrease, the width of the stress-strain hysteresis decreases and irreversible strain accumulates. This evolution is strong during early cycling. It is generally assumed that these effects, which saturate after about a hundred cycles, are associated with the elementary processes which govern dislocation plasticity and stress-induced martensitic transformations. Dislocations can do both, stabilize martensite (through their stress fields) and contribute to accumulation of irreversible strain. While it is accepted that dislocations may alter the cyclic stress-strain behavior during stress-induced martensitic transformations in NiTi, it is generally assumed that atomic reordering processes (which are known to significantly affect martensitic transformations in Cu-base shape memory alloys) play no role. In the present investigation we show that hold times in saturated stress-strain cycles show significant effects which are smaller than, but similar in type to those in Cu-base alloys. Further work is required to fully rationalize the microstructural origin of our findings.

  12. Differentiated effect of ageing on the enzymes of Krebs' cycle, electron transfer complexes and glutamate metabolism of non-synaptic and intra-synaptic mitochondria from cerebral cortex.

    Science.gov (United States)

    Villa, R F; Gorini, A; Hoyer, S

    2006-11-01

    The effect of ageing on the activity of enzymes linked to Krebs' cycle, electron transfer chain and glutamate metabolism was studied in three different types of mitochondria of cerebral cortex of 1-year old and 2-year old male Wistar rats. We assessed the maximum rate (V(max)) of the mitochondrial enzyme activities in non-synaptic perikaryal mitochondria, and in two populations of intra-synaptic mitochondria. The results indicated that: (i) in normal, steady-state cerebral cortex the values of the catalytic activities of the enzymes markedly differed in the various populations of mitochondria; (ii) in intra-synaptic mitochondria, ageing affected the catalytic properties of the enzymes linked to Krebs' cycle, electron transfer chain and glutamate metabolism; (iii) these changes were more evident in intra-synaptic "heavy" than "light" mitochondria. These results indicate a different age-related vulnerability of subpopulations of mitochondria in vivo located into synapses than non-synaptic ones.

  13. Effect of ageing and ischemia on enzymatic activities linked to Krebs' cycle, electron transfer chain, glutamate and aminoacids metabolism of free and intrasynaptic mitochondria of cerebral cortex.

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    Villa, Roberto Federico; Gorini, Antonella; Hoyer, Siegfried

    2009-12-01

    The effect of ageing and the relationships between the catalytic properties of enzymes linked to Krebs' cycle, electron transfer chain, glutamate and aminoacid metabolism of cerebral cortex, a functional area very sensitive to both age and ischemia, were studied on mitochondria of adult and aged rats, after complete ischemia of 15 minutes duration. The maximum rate (Vmax) of the following enzyme activities: citrate synthase, malate dehydrogenase, succinate dehydrogenase for Krebs' cycle; NADH-cytochrome c reductase as total (integrated activity of Complex I-III), rotenone sensitive (Complex I) and cytochrome oxidase (Complex IV) for electron transfer chain; glutamate dehydrogenase, glutamate-oxaloacetate-and glutamate-pyruvate transaminases for glutamate metabolism were assayed in non-synaptic, perikaryal mitochondria and in two populations of intra-synaptic mitochondria, i.e., the light and heavy mitochondrial fraction. The results indicate that in normal, steady-state cerebral cortex, the value of the same enzyme activity markedly differs according (a) to the different populations of mitochondria, i.e., non-synaptic or intra-synaptic light and heavy, (b) and respect to ageing. After 15 min of complete ischemia, the enzyme activities of mitochondria located near the nucleus (perikaryal mitochondria) and in synaptic structures (intra-synaptic mitochondria) of the cerebral tissue were substantially modified by ischemia. Non-synaptic mitochondria seem to be more affected by ischemia in adult and particularly in aged animals than the intra-synaptic light and heavy mitochondria. The observed modifications in enzyme activities reflect the metabolic state of the tissue at each specific experimental condition, as shown by comparative evaluation with respect to the content of energy-linked metabolites and substrates. The derangements in enzyme activities due to ischemia is greater in aged than in adult animals and especially the non-synaptic and the intra-synaptic light

  14. Effects of aging on the recycling via the pentose cycle and on the kinetics of glycogen and protein metabolism in various organs of the rat.

    Science.gov (United States)

    Niedermüller, H

    1986-12-01

    The rate of metabolic kinetics and the frequency of biological cycles may be correlated with the rate of aging and the maximum life-span potential. Therefore, investigations either into changes with age of such parameters within one species or into differences between species may give some information about the genetic programming of the aging process. Male Sprague-Dawley rats aged 3.5, 7, 12, 17, 23 and 33 months (m) were used to determine the changes with age of those metabolic pathways mentioned in the title, using the liver, kidney, brain, heart and the skeletal muscle. The maximum percentage of glucose utilization via the pentose pathway, compared to the total glucose utilization, was calculated after intravenous administration of D-[1-14C]- and D-[6-14C]glucose by the determination of the trioses (as lipids) 3 hours after the application. Glycogen kinetics was determined analogously. Total protein metabolism was observed using the essential amino acid L-[2,5-3H]histidine. The results indicate a decrease in the glucose utilization via the pentose pathway in the course of aging in liver, kidney, heart and skeletal muscle and a decrease from 3.5 months on in brain, a small but not significant change of the kinetics of glycogen metabolism (a lower turnover), and a reduced rate of protein synthesis in liver, kidney, heart and brain through an age of 23 months, followed by an elevated rate. Brain did not show any changes. The reduction of the pentose pathway may possibly be the cause of higher lipofuscin accumulation in the cells of some organs, lacking sufficient reduction equivalents for lipid metabolism. Furthermore, there could exist a connection with the reduced protein turnover, because less riboses are provided for the synthesis of nucleic acids.

  15. The reproductive-cell cycle theory of aging: an update.

    Science.gov (United States)

    Atwood, Craig S; Bowen, Richard L

    2011-01-01

    The Reproductive-Cell Cycle Theory posits that the hormones that regulate reproduction act in an antagonistic pleiotrophic manner to control aging via cell cycle signaling; promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence. Since reproduction is the most important function of an organism from the perspective of the survival of the species, if reproductive-cell cycle signaling factors determine the rate of growth, determine the rate of development, determine the rate of reproduction, and determine the rate of senescence, then by definition they determine the rate of aging and thus lifespan. The theory is able to explain: 1) the simultaneous regulation of the rate of aging and reproduction as evidenced by the fact that environmental conditions and experimental interventions known to extend longevity are associated with decreased reproductive-cell cycle signaling factors, thereby slowing aging and preserving fertility in a hostile reproductive environment; 2) two phenomena that are closely related to species lifespan-the rate of growth and development and the ultimate size of the animal; 3). the apparent paradox that size is directly proportional to lifespan and inversely proportional to fertility between species but vice versa within a species; 4). how differing rates of reproduction between species is associated with differences in their lifespan; 5). why we develop aging-related diseases; and 6). an evolutionarily credible reason for why and how aging occurs-these hormones act in an antagonistic pleiotrophic manner via cell cycle signaling; promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence (dyosis). In essence, the Reproductive-Cell Cycle Theory can explain aging in all sexually reproductive life

  16. The Effect of Cycling Intensity on Cycling Economy During Seated and Standing Cycling.

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    Arkesteijn, Marco; Jobson, Simon; Hopker, James; Passfield, Louis

    2016-10-01

    Previous research has shown that cycling in a standing position reduces cycling economy compared with seated cycling. It is unknown whether the cycling intensity moderates the reduction in cycling economy while standing. The aim was to determine whether the negative effect of standing on cycling economy would be decreased at a higher intensity. Ten cyclists cycled in 8 different conditions. Each condition was either at an intensity of 50% or 70% of maximal aerobic power at a gradient of 4% or 8% and in the seated or standing cycling position. Cycling economy and muscle activation level of 8 leg muscles were recorded. There was an interaction between cycling intensity and position for cycling economy (P = .03), the overall activation of the leg muscles (P = .02), and the activation of the lower leg muscles (P = .05). The interaction showed decreased cycling economy when standing compared with seated cycling, but the difference was reduced at higher intensity. The overall activation of the leg muscles and the lower leg muscles, respectively, increased and decreased, but the differences between standing and seated cycling were reduced at higher intensity. Cycling economy was lower during standing cycling than seated cycling, but the difference in economy diminishes when cycling intensity increases. Activation of the lower leg muscles did not explain the lower cycling economy while standing. The increased overall activation, therefore, suggests that increased activation of the upper leg muscles explains part of the lower cycling economy while standing.

  17. Packaging Reliability Effect of ENIG and ENEPIG Surface Finishes in Board Level Thermal Test under Long-Term Aging and Cycling.

    Science.gov (United States)

    Shen, Chaobo; Hai, Zhou; Zhao, Cong; Zhang, Jiawei; Evans, John L; Bozack, Michael J; Suhling, Jeffrey C

    2017-04-26

    This study illustrates test results and comparative literature data on the influence of isothermal aging and thermal cycling associated with Sn-1.0Ag-0.5Cu (SAC105) and Sn-3.0Ag-0.5Cu (SAC305) ball grid array (BGA) solder joints finished with ENIG and ENEPIG on the board side and ENIG on the package side compared with ImAg plating on both sides. The resulting degradation data suggests that the main concern for 0.4 mm pitch 10 mm package size BGA is package side surface finish, not board side. That is, ENIG performs better than immersion Ag for applications involving long-term isothermal aging. SAC305, with a higher relative fraction of Ag₃Sn IMC within the solder, performs better than SAC105. SEM and polarized light microscope analysis show cracks propagated from the corners to the center or even to solder bulk, which eventually causes fatigue failure. Three factors are discussed: IMC, grain structure, and Ag₃Sn particle. The continuous growth of Cu-Sn intermetallic compounds (IMC) and grains increase the risk of failure, while Ag₃Sn particles seem helpful in blocking the crack propagation.

  18. The influence of training status, age, and muscle fiber type on cycling efficiency and endurance performance.

    Science.gov (United States)

    Hopker, James G; Coleman, Damian A; Gregson, Hannah C; Jobson, Simon A; Von der Haar, Tobias; Wiles, Jonathan; Passfield, Louis

    2013-09-01

    The purpose of this study was to assess the influence of age, training status, and muscle fiber-type distribution on cycling efficiency. Forty men were recruited into one of four groups: young and old trained cyclists, and young and old untrained individuals. All participants completed an incremental ramp test to measure their peak O2 uptake, maximal heart rate, and maximal minute power output; a submaximal test of cycling gross efficiency (GE) at a series of absolute and relative work rates; and, in trained participants only, a 1-h cycling time trial. Finally, all participants underwent a muscle biopsy of their right vastus lateralis muscle. At relative work rates, a general linear model found significant main effects of age and training status on GE (P 0.05). Power output in the 1-h performance trial was predicted by average O2 uptake and GE, with standardized β-coefficients of 0.94 and 0.34, respectively, although some mathematical coupling is evident. These data demonstrate that muscle fiber type does not affect cycling efficiency and was not influenced by the aging process. Cycling efficiency and the percentage of type I muscle fibers were influenced by training status, but only GE at 120 revolutions/min was seen to predict cycling performance.

  19. Associations of menstrual cycle irregularities with age, obesity and phenotype in patients with polycystic ovary syndrome.

    Science.gov (United States)

    Panidis, Dimitrios; Tziomalos, Konstantinos; Papadakis, Efstathios; Chatzis, Panagiotis; Kandaraki, Eleni A; Tsourdi, Elena A; Macut, Djuro; Bjekic-Macut, Jelica; Marthopoulos, Apostolos; Katsikis, Ilias

    2015-01-01

    Limited data suggest that menstrual cycle abnormalities are more pronounced in younger and more obese patients with polycystic ovary syndrome (PCOS). We aimed to evaluate the association between menstrual cycle pattern and age, obesity and PCOS phenotype in a large population of women with PCOS. We studied 1,297 women with PCOS and divided them according to: a) age in ≤ 20, 21-30 and > 30 years old, b) body mass index in normal weight, overweight and obese and c) PCOS phenotype in phenotype 1 (anovulation, hyperandrogenemia and polycystic ovaries), 2 (anovulation and hyperandrogenemia without polycystic ovaries), 3 (hyperandrogenemia and polycystic ovaries without anovulation) and 4 (anovulation and polycystic ovaries without hyperandrogenemia). The proportion of women with regular menstrual cycles progressively increased in the older age groups, being 8.1, 10.5 and 12.7% in women ≤ 20, 21-30 and > 30 years old, respectively (p = 0.037). The proportion of women with regular menstrual cycles did not differ between normal weight and obese women but was higher in overweight women (9.3, 9.4 and 13%, respectively; p = 0.020). The proportion of women with regular cycles alternating with irregular cycles was highest in women with phenotype 4, intermediate in women with phenotype 2 and lowest in women with phenotype 1 (74.3, 69.4 and 61.7%, respectively; p = 0.027). Menstrual cycle pattern is more irregular in women with the "classic" PCOS phenotypes than in phenotype 4 but appears to normalize with ageing. On the other hand, obesity does not appear to have an important effect on menstrual cycle pattern in PCOS.

  20. In the aging housefly aconitase is the only citric acid cycle enzyme to decline significantly.

    Science.gov (United States)

    Yarian, Connie S; Sohal, Rajindar S

    2005-04-01

    The main objective of this study was to determine if the activities of the mitochondrial citric acid cycle enzymes are altered during the normal aging process. Flight muscle mitochondria of houseflies of different ages were used as a model system because of their apparent age-related decline in bioenergetic efficiency, evident as a failure of flying ability. The maximal activities of each of the citric acid cycle enzymes were determined in preparations of mitochondria from flies of relatively young, middle, and old age. Aconitase was the only enzyme exhibiting altered activity during aging. The maximal activity of aconitase from old flies was decreased by 44% compared to that from young flies while the other citric acid cycle enzymes showed no change in activity with age. It is suggested that the selective age-related decrease in aconitase activity is likely to contribute to a decline in the efficiency of mitochondrial bioenergetics, as well as result in secondary effects associated with accumulation of citrate and redox-active iron.

  1. Characteristics and Behavior of Cycled Aged Lithium Ion Cells

    Science.gov (United States)

    2010-01-01

    service cycle and provide the cornerstone for safety analysis. 18650 Cells with representative chemistry of cells contained in current Army procured...their relevance to this effort warrants inclusion. 1-3 EXPERIMENTAL Representative 18650 cells were cycled at different rates and environmental...conditions. The 18650 chemistry used in this effort is a LiCoO2 lithium ion electrochemical cell. The bulk of this effort was conducted with 1.5 Amp-hr

  2. The role of mitochondrial DNA mutations in aging and sarcopenia: implications for the mitochondrial vicious cycle theory of aging.

    Science.gov (United States)

    Hiona, Asimina; Leeuwenburgh, Christiaan

    2008-01-01

    Aging is associated with a progressive loss of skeletal muscle mass and strength and the mechanisms mediating these effects likely involve mitochondrial DNA (mtDNA) mutations, mitochondrial dysfunction and the activation of mitochondrial-mediated apoptosis. Because the mitochondrial genome is densely packed and close to the main generator of reactive oxygen species (ROS) in the cell, the electron transport chain (ETC), an important role for mtDNA mutations in aging has been proposed. Point mutations and deletions in mtDNA accumulate with age in a wide variety of tissues in mammals, including humans, and often coincide with significant tissue dysfunction. Here, we examine the evidence supporting a causative role for mtDNA mutations in aging and sarcopenia. We review experimental outcomes showing that mtDNA mutations, leading to mitochondrial dysfunction and possibly apoptosis, are causal to the process of sarcopenia. Moreover, we critically discuss and dispute an important part of the mitochondrial 'vicious cycle' theory of aging which proposes that accumulation of mtDNA mutations may lead to an enhanced mitochondrial ROS production and ever increasing oxidative stress which ultimately leads to tissue deterioration and aging. Potential mechanism(s) by which mtDNA mutations may mediate their pathological consequences in skeletal muscle are also discussed.

  3. Positive aging in demanding workplaces: The gain cycle between job satisfaction and work engagement

    Directory of Open Access Journals (Sweden)

    Dina Guglielmi

    2016-08-01

    Full Text Available Nowadays organizations have to cope with two related challenges: maintaining an engaged and highly performing workforce and, at the same time, protecting and increasing employees’ well-being and job satisfaction under conditions of a generalized increase of job overload, in an increasingly growing older population. According to the motivational process of the JD-R model, a work environment with many organizational resources will foster work engagement, which in turn will increase the likelihood of positive personal and organizational outcomes, such as job satisfaction, performance, and intention to stay. However, it is not clear how this motivational process could work in different age cohorts, as older workers may have different priorities to those of younger colleagues. Postulating the existence of a gain-cycle in the relationship between work engagement and outcomes, in this study we tested a longitudinal moderated mediation model in which job satisfaction increases over time through an increment in work engagement. We hypothesized that this process is moderated by job workload and aging. We collected data in public administrations in Northern Italy in order to measure work engagement and job satisfaction. 556 workers aged between 50 to 64 replied to the survey twice (the first time and eight months later. The findings confirmed a moderated mediation model, in which job satisfaction at time 1 increased work engagement, which in turn fostered job satisfaction eight months later, confirming the hypothesized gain-cycle. This relationship was shown to be moderated by the joint influence of job demand intensity and age: higher job demands and younger age are related to the maximum level of level gain cycle, while the same high level of job demands, when associated with older age, appears unable to stimulate a similar effect. The results confirm that, on one hand, older workers cannot be seen as a homogeneous group and, on the other hand, the

  4. Positive Aging in Demanding Workplaces: The Gain Cycle between Job Satisfaction and Work Engagement

    Science.gov (United States)

    Guglielmi, Dina; Avanzi, Lorenzo; Chiesa, Rita; Mariani, Marco G.; Bruni, Ilaria; Depolo, Marco

    2016-01-01

    Nowadays organizations have to cope with two related challenges: maintaining an engaged and highly performing workforce and, at the same time, protecting and increasing employees’ well-being and job satisfaction under conditions of a generalized increase of job demand, in an increasingly growing older population. According to the motivational process of the JD-R model, a work environment with many organizational resources will foster work engagement, which in turn will increase the likelihood of positive personal and organizational outcomes, such as job satisfaction, performance, and intention to stay. However, it is not clear how this motivational process could work in different age cohorts, as older workers may have different priorities to those of younger colleagues. Postulating the existence of a gain-cycle in the relationship between work engagement and outcomes, in this study we tested a longitudinal moderated mediation model in which job satisfaction increases over time through an increment in work engagement. We hypothesized that this process is moderated by job demand and aging. We collected data in public administrations in Northern Italy in order to measure work engagement and job satisfaction. 556 workers aged between 50 and 64 replied to the survey twice (the first time and 8 months later). The findings confirmed a moderated mediation model, in which job satisfaction at time 1 increased work engagement, which in turn fostered job satisfaction 8 months later, confirming the hypothesized gain-cycle. This relationship was shown to be moderated by the joint influence of job demand intensity and age: higher job demands and younger age are related to the maximum level of level gain cycle, while the same high level of job demands, when associated with older age, appears unable to stimulate a similar effect. The results confirm that, on one hand, older workers cannot be seen as a homogeneous group and, on the other hand, the importance of considering the

  5. Positive Aging in Demanding Workplaces: The Gain Cycle between Job Satisfaction and Work Engagement.

    Science.gov (United States)

    Guglielmi, Dina; Avanzi, Lorenzo; Chiesa, Rita; Mariani, Marco G; Bruni, Ilaria; Depolo, Marco

    2016-01-01

    Nowadays organizations have to cope with two related challenges: maintaining an engaged and highly performing workforce and, at the same time, protecting and increasing employees' well-being and job satisfaction under conditions of a generalized increase of job demand, in an increasingly growing older population. According to the motivational process of the JD-R model, a work environment with many organizational resources will foster work engagement, which in turn will increase the likelihood of positive personal and organizational outcomes, such as job satisfaction, performance, and intention to stay. However, it is not clear how this motivational process could work in different age cohorts, as older workers may have different priorities to those of younger colleagues. Postulating the existence of a gain-cycle in the relationship between work engagement and outcomes, in this study we tested a longitudinal moderated mediation model in which job satisfaction increases over time through an increment in work engagement. We hypothesized that this process is moderated by job demand and aging. We collected data in public administrations in Northern Italy in order to measure work engagement and job satisfaction. 556 workers aged between 50 and 64 replied to the survey twice (the first time and 8 months later). The findings confirmed a moderated mediation model, in which job satisfaction at time 1 increased work engagement, which in turn fostered job satisfaction 8 months later, confirming the hypothesized gain-cycle. This relationship was shown to be moderated by the joint influence of job demand intensity and age: higher job demands and younger age are related to the maximum level of level gain cycle, while the same high level of job demands, when associated with older age, appears unable to stimulate a similar effect. The results confirm that, on one hand, older workers cannot be seen as a homogeneous group and, on the other hand, the importance of considering the role

  6. Analysis of Ageing Effect on Li-Polymer Batteries.

    Science.gov (United States)

    Barcellona, Simone; Brenna, Morris; Foiadelli, Federica; Longo, Michela; Piegari, Luigi

    2015-01-01

    Lithium-ion batteries are a key technology for current and future energy storage in mobile and stationary application. In particular, they play an important role in the electrification of mobility and therefore the battery lifetime prediction is a fundamental aspect for successful market introduction. Numerous studies developed ageing models capable of predicting battery life span. Most of the previous works compared the effect of the ageing factors to a battery's cycle life. These cycles are identical, which is not the case for electric vehicles applications. Indeed, most of the available information is based on results from laboratory testing, under very controlled environments, and using ageing protocols, which may not correctly reflect the actual utilization. For this reason, it is important to link the effect of duty cycles with the ageing of the batteries. This paper proposes a simple method to investigate the effect of the duty cycle on the batteries lifetime through tests performed on different cells for different kinds of cycle. In this way, a generic complex cycle can be seen as a composition of elemental cycles by means of Rainflow procedures. Consequently, the ageing due to any cycle can be estimated starting from the knowledge of simpler cycles.

  7. Analysis of Ageing Effect on Li-Polymer Batteries

    Directory of Open Access Journals (Sweden)

    Simone Barcellona

    2015-01-01

    Full Text Available Lithium-ion batteries are a key technology for current and future energy storage in mobile and stationary application. In particular, they play an important role in the electrification of mobility and therefore the battery lifetime prediction is a fundamental aspect for successful market introduction. Numerous studies developed ageing models capable of predicting battery life span. Most of the previous works compared the effect of the ageing factors to a battery’s cycle life. These cycles are identical, which is not the case for electric vehicles applications. Indeed, most of the available information is based on results from laboratory testing, under very controlled environments, and using ageing protocols, which may not correctly reflect the actual utilization. For this reason, it is important to link the effect of duty cycles with the ageing of the batteries. This paper proposes a simple method to investigate the effect of the duty cycle on the batteries lifetime through tests performed on different cells for different kinds of cycle. In this way, a generic complex cycle can be seen as a composition of elemental cycles by means of Rainflow procedures. Consequently, the ageing due to any cycle can be estimated starting from the knowledge of simpler cycles.

  8. Tracer Cycles and Water Ages in Heterogeneous Catchments and Aquifers

    Science.gov (United States)

    Kirchner, J. W.; Jasechko, S.

    2015-12-01

    Estimates of catchment mean transit times are often based on seasonal cycles of stable isotope tracers in precipitation and streamflow. In many cases these transit time estimates are derived directly from sine-wave fitting to the observed seasonal isotope cycles. Broadly similar results are also obtained from time-domain convolutions or explicit tracer modeling, because here too the dominant tracer signal that these techniques seek to match is the seasonal isotopic cycle. Here I use simple benchmark tests to show that estimates of mean transit times based on seasonal tracer cycles will typically be wrong by several hundred percent, when applied to catchments with realistic degrees of spatial heterogeneity. This aggregation bias arises from the strong nonlinearity in the relationship between tracer cycle amplitude and mean travel time. A similar bias arises in estimates of mean transit times in nonstationary catchments. Since typical real-world catchments are both spatially heterogeneous and nonstationary, this analysis poses a fundamental challenge to tracer-based estimates of mean transit times. I propose an alternative storage metric, the fraction of "young water" in streamflow, defined as the fraction of runoff with transit times of less than roughly 0.2 years. I show that young water fractions are virtually free of aggregation bias; that is, they can be accurately estimated from tracer cycles in highly heterogeneous mixtures of subcatchments with strongly contrasting transit time distributions. They can also be reliably estimated in strongly nonstationary catchments. Young water fractions can be estimated separately for individual flow regimes, allowing direct determination of how shifts in hydraulic regime alter the fraction of water reaching the stream by fast flowpaths. One can also estimate the chemical composition of idealized "young water" and "old water" end-members, using relationships between young water fractions and solute concentrations across

  9. 年龄和移植胚胎数目对冻融胚胎移植周期结局的影响%Effect of age and embryo number transferred on outcomes of frozen-thawed cycles

    Institute of Scientific and Technical Information of China (English)

    刘琦; 张翠莲

    2012-01-01

    Objective To investigate the effect of age and embryo number transferred on clinical pregnancy rate,implantation rate and multiple pregnancy rates of frozen-thawed cycles (FET).Methods We retrieved 1251 patients underwent FET cycles from January 2010 to May 2012.These cycles were divided into 4 groups according female age:group A,< 30 years old,n =549 ; group B,30-34 years old,n =433; group C,35-38 years old,n =168; group D,≥39 years old,n =101.The clinical pregnancy rate,implantation rate and multiple pregnancy rate with 2 or 3 embryos transferred of each group were analyzed.Results The clinical pregnancy rate and implantation rate were decreased significantly with age of patients (P < 0.05),but there was no significant difference in multiple pregnancy rates (P > 0.05).The differences of clinical pregnancy rate,implantation rate with 2 or 3 embryos transferred in group A,B and C were not significant (P > 0.05).The clinical pregnancy rate with 3 embryo transferred was significantly higher than with 2 in group D (P < 0.05).The multiple pregnancy rates with 2 embryos transferred was significantly lower than with 3 in group A,but there was no significant difference in multiple pregnancy rate with 2 and 3 of group B,C and D.Conclusions In frozen-thawed embryo transfer cycles,ideal clinical pregnancy rate could be received from patients with age ≤38 years old and 2 embryos transferred; and for patients aged ≥39 years old,better pregnancy rate could be obtained when 3 embryos were transferred; it was inevitable that multiple pregnancy was got no matter 2 or 3 embryos were transferred.%目的 探讨冻融胚胎移植(FET)周期中年龄和移植胚胎数目对临床妊娠率、种植率和多胎妊娠率的影响.方法 回顾性分析河南省人民医院生殖医学中心2010年1月至2012年5月期间行FET治疗周期的患者1251例,按女方患者年龄分为4组:<30岁为A组(n=549),30~34岁为B组(n=433),35 ~ 38岁为C组(n=168),>39

  10. In vitro fertilization and embryo transfer in seminatural cycles for patients with ovarian aging.

    Science.gov (United States)

    Castelo Branco, Altina; Achour-Frydman, Nelly; Kadoch, Jacques; Fanchin, Renato; Tachdjian, Gerard; Frydman, René

    2005-10-01

    To investigate whether seminatural cycle is a reasonable management for ovarian aging patients. Prospective study. ART Unit, Clamart, France. Seventy-five women, 158 cycles. Infertile women who presented with ovarian aging (defined as low ovarian reserve and characterized by cycle day 3 high FSH, high E2, and/or low inhibin B and/or previous cycle cancellations due to poor ovarian response to COH) were studied. Patients were offered up to three cycles. Treatment was scheduled as follows. From cycle day 8 onward the selection of the dominant follicle was monitored by ultrasound and hormonal measurements. When the dominant follicle appeared, patients received GnRH antagonist and, thereafter, hMG to support further follicular development. Implantation rate and clinical pregnancy. Twenty-eight of 158 cycles were cancelled (17.7%). Oocyte pickups were performed in 119 (75.3%) cycles, 91 (57.6%) mature oocytes were retrieved, and 67 (42.4%) embryos transferred. Nineteen clinical pregnancies were obtained; the cumulative pregnancy rate per patient, after 3 cycles, was 35.2%. Use of a seminatural cycle is a reasonable management for patients with ovarian aging who have ovulatory menstrual cycles. It achieves a high implantation rate (28.3%).

  11. Mechanistic insights into aging, cell cycle progression, and stress response

    Directory of Open Access Journals (Sweden)

    Troy Anthony Alan Harkness

    2012-06-01

    Full Text Available The longevity of an organism depends on the health of its cells. Throughout life cells are exposed to numerous intrinsic and extrinsic stresses, such as free radicals, generated through mitochondrial electron transport, and ultraviolet irradiation. The cell has evolved numerous mechanisms to scavenge free radicals and repair damage induced by these insults. One mechanism employed by the yeast Saccharomyces cerevisiae to combat stress utilizes the Anaphase Promoting Complex (APC, an essential multi-subunit ubiquitin-protein ligase structurally and functionally conserved from yeast to humans that controls progression through mitosis and G1. We have observed that yeast cells expressing compromised APC subunits are sensitive to multiple stresses and have shorter replicative and chronological lifespans. In a pathway that runs parallel to that regulated by the APC, members of the Forkhead box (Fox transcription factor family also regulate stress responses. The yeast Fox orthologues Fkh1 and Fkh2 appear to drive the transcription of stress response factors and slow early G1 progression, while the APC seems to regulate chromatin structure, chromosome segregation, and resetting of the transcriptome in early G1. In contrast, under non-stress conditions, the Fkhs play a complex role in cell cycle progression, partially through activation of the APC. Direct and indirect interactions between the APC and the yeast Fkhs appear to be pivotal for lifespan determination. Here we explore the potential for these interactions to be evolutionarily conserved as a mechanism to balance cell cycle regulation with stress responses.

  12. Age and sex dependent changes in liver gene expression during the life cycle of the rat

    Directory of Open Access Journals (Sweden)

    Branham William S

    2010-11-01

    Full Text Available Abstract Background Age- and sex-related susceptibility to adverse drug reactions and disease is a key concern in understanding drug safety and disease progression. We hypothesize that the underlying suite of hepatic genes expressed at various life cycle stages will impact susceptibility to adverse drug reactions. Understanding the basal liver gene expression patterns is a necessary first step in addressing this hypothesis and will inform our assessments of adverse drug reactions as the liver plays a central role in drug metabolism and biotransformation. Untreated male and female F344 rats were sacrificed at 2, 5, 6, 8, 15, 21, 52, 78, and 104 weeks of age. Liver tissues were collected for histology and gene expression analysis. Whole-genome rat microarrays were used to query global expression profiles. Results An initial list of differentially expressed genes was selected using criteria based upon p-value (p Conclusions These results suggest an underlying role for genes in specific clusters in potentiating age- and sex-related differences in susceptibility to adverse health effects. Furthermore, such a comprehensive picture of life cycle changes in gene expression deepens our understanding and informs the utility of liver gene expression biomarkers.

  13. Firm age, business cycles and aggregate labor market dynamics

    NARCIS (Netherlands)

    P. Sedláček

    2011-01-01

    Job creation and destruction rates fall with a firm's age, young businesses have higher exit rates, conditional on survival they grow faster and given their employment shares they create relatively more jobs than older firms. In fact, recent studies show that the well established negative relationsh

  14. Age-related decrements in cycling and running perfor- mance

    African Journals Online (AJOL)

    Enrique

    while exercise can reduce the rate of decline in age-related exercise capacity ... a gradual increase in degenerative changes in both type I and type II fibres ..... ery of vertical jump height and heart rate vs. running speed after a 90 km foot race.

  15. First accelerated ageing cycling test on super capacitors for transportation applications: methodology, first results

    Energy Technology Data Exchange (ETDEWEB)

    Coquery, G.; Lallemand, R.; Kauv, J. [Institut National de Recherche sur les Transports et leur Securite (INRETS), Lab. des Technologies Nouvelles, 94 - Arcueil (France); Monts, A. de; Soucaze-Guillous, B. [Societe Nationale des Chemins de fer Francais (SNCF), Dir. de la Recherche, 75 - Paris (France); Chabas, J.; Darnault, A. [VALEO Electrical Energy Management, 94 - Creteil (France)

    2004-07-01

    Automotive and railway electrical traction systems are submitted to high power cycles due to the urban mission profiles. In order to increase the energy efficiency and to reduce global pollutant emission, the buffer energy storage by means super-capacitor offer major advantages to optimise the traction energy management with the highest level of regenerative braking energy. Super-capacitors are promising for the energy management between traction chain and electrical supplying systems. Because the effects of the charge-discharge cycles are a strong limitation of the batteries lifetime, it was decided to evaluate the capabilities of this technology concerning the ageing effects due to these strong cycling power stresses link to the urban traffic. Today, there are no publications to discuss about this phenomena, however it appears as a fundamental acknowledge to design the super-capacitors assembly. The first step was to establish a typical mission profile representative of the transportation working conditions, to propose a preliminary test plan, and to define a measurement methodology. The presented investigations are linked to research projects on automotive and railway applications. (authors)

  16. The Effect of Cycling Cadence on Subsequent 10km Running Performance in Well-Trained Triathletes

    OpenAIRE

    Tew, Garry A.

    2005-01-01

    The aim of this study was to examine the effects of different pedalling cadences on the performance of a subsequent 10km treadmill run. Eight male triathletes (age 38.9 ± 15.4 years, body mass 72.2 ± 5.2 kg, and stature 176 ± 6 cm; mean ± SD) completed a maximal cycling test, one isolated run (10km), and then three randomly ordered cycle-run sessions (65 minutes cycling + 10km run). During the cycling bout of the cycle-run sessions, subjects cycled at an intensity corresponding to 70% Pmax wh...

  17. Functional fatigue recovery of superelastic cycled NiTi wires based on near 100 °C aging treatments

    Directory of Open Access Journals (Sweden)

    Isalgue Antonio

    2015-01-01

    Full Text Available Functional fatigue affecting superelastic behaviour of NiTi wires includes an accumulation of residual strain and an uneven decrement of transformation stress on cycling. Although this evolution is observed to diminish asymptotically, it represents an important loss in the maximum recoverable strain level and in the hysteretic dissipative capacity of the material. In this work, the effect of moderate temperature aging treatment on the functionally degraded material properties was studied with two experimental setups. NiTi pseudoelastic wire samples of 0.5 and 2.46 mm diameter were subjected to different cycling programs intercalated by aging treatments of different durations up to 48 h at 100°C. Results show that important levels of recovery on the residual strains and the transformation stresses were attained after the aging treatments. The analysis indicates that the characteristics of the recovered cycles are rather independent from the treatment duration and from the reached condition before each treatment.

  18. Recovery from Age-Related Infertility under Environmental Light-Dark Cycles Adjusted to the Intrinsic Circadian Period

    OpenAIRE

    Nana N. Takasu; Takahiro J. Nakamura; Isao T. Tokuda; Takeshi Todo; Gene D. Block; Wataru Nakamura

    2015-01-01

    © 2015 The Authors. Female reproductive function changes during aging with the estrous cycle becoming more irregular during the transition to menopause. We found that intermittent shifts of the light-dark cycle disrupted regularity of estrous cycles in middle-aged female mice, whose estrous cycles were regular under unperturbed 24-hr light-dark cycles. Although female mice deficient in Cry1 or Cry2, the core components of the molecular circadian clock, exhibited regular estrous cycles during ...

  19. Age at menarche and menstrual cycle pattern among school adolescent girls in Central India.

    Science.gov (United States)

    Dambhare, Dharampal G; Wagh, Sanjay V; Dudhe, Jayesh Y

    2012-01-01

    The onset of menstruation is part of the maturation process. However, variability in menstrual cycle characteristics and menstrual disorders are common. The purpose of this study was to determine the age at menarche and patterns of menstruation among school adolescent girls and explore its variation across socio-economic and demographic factors. This is a cross-sectional descriptive study carried out on 1100 school adolescent girls in district Wardha, Central India. Data were collected using a self-administered structured questionnaire on menstruation. Data was entered and analyzed by using Epi Info 6.04 software package. Chi- square value was used for testing statistical significance. Mean ages of menarche were 13.51 + 1.04 years and 13.67 + 0.8 years for urban and rural areas respectively. Abnormal cycle length was common and affected 30.48%. The majority 56.15 experienced dysmenorrhoea and 56.16 percent had premenstrual syndrome. Self medication was practiced by 7.13% of the adolescent girls. The most common premenstrual symptom was headache 26.74%. Absenteeism from the school 13.9% was the effect of menstruation related problems on their daily routine. Dysmenorrhea and premenstrual symptoms were perceived as most distressing symptoms leading to school absenteeism. Majority of the girls 75.58% had discussed menstrual problems with someone, most commonly with their mothers 38.15%. There was a general lack of information about menstrual issues especially with regards to cycle length, duration of menses and age at menarche. Girls from families of high socio-economic class have significantly lower mean menarcheal age in both urban and rural area. The mean age of menarche was significantly higher in girls involved in vigorous sporting activity in urban area compared to their non-sporting counterparts. Age at menarche was delayed. The menstrual disorders among female adolescents are common. A school health education on menstrual problems targeting adolescent girls and

  20. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process.

    Science.gov (United States)

    Salminen, Antero; Kauppinen, Anu; Hiltunen, Mikko; Kaarniranta, Kai

    2014-07-01

    Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process.

  1. Aging, rhythms of physical performance, and adjustment to changes in the sleep-activity cycle.

    Science.gov (United States)

    Reilly, T; Waterhouse, J; Atkinson, G

    1997-11-01

    Shiftwork causes disturbances of the normal sleep-wake cycle and circadian rhythm. There is concern that aging workers have more problems than younger counterparts when the human body clock is disrupted. This review considers issues relating to aging, the circadian body clock, and adjustment to altered sleep-wake schedules. Reports on effects of aging on the human body clock were reviewed. Research concerned with adjustment to circadian phase shifts (as occurs in night work) was considered. With aging there is an increased tendency towards morningness which is linked with difficulties in sleeping. The peak time and amplitude of normal circadian rhythms are altered. Tolerance of shiftwork can be linked with social factors as well as adaptation of the body clock. People habituated to night work seem to have developed mechanisms which allow them to cope with disruptions to lifestyle and the endogenous body clock. Elderly people are more suited to phase advances, as occur in morning workshifts, than to phase delays such as nocturnal work.

  2. The use and risk of portable electronic devices while cycling among different age groups

    NARCIS (Netherlands)

    Goldenbeld, C.; Houtenbos, M.; Ehlers, E.; De Waard, D.

    Introduction: In the Netherlands, a survey was set up to monitor the extent of the use of portable, electronic devices while cycling amongst different age groups of cyclists and to estimate the possible consequences for safety. Method: The main research questions concerned age differences in the

  3. Tree Age Distributions Reveal Large-Scale Disturbance-Recovery Cycles in Three Tropical Forests

    Science.gov (United States)

    Vlam, Mart; van der Sleen, Peter; Groenendijk, Peter; Zuidema, Pieter A.

    2017-01-01

    Over the past few decades there has been a growing realization that a large share of apparently ‘virgin’ or ‘old-growth’ tropical forests carries a legacy of past natural or anthropogenic disturbances that have a substantial effect on present-day forest composition, structure and dynamics. Yet, direct evidence of such disturbances is scarce and comparisons of disturbance dynamics across regions even more so. Here we present a tree-ring based reconstruction of disturbance histories from three tropical forest sites in Bolivia, Cameroon, and Thailand. We studied temporal patterns in tree regeneration of shade-intolerant tree species, because establishment of these trees is indicative for canopy disturbance. In three large areas (140–300 ha), stem disks and increment cores were collected for a total of 1154 trees (>5 cm diameter) from 12 tree species to estimate the age of every tree. Using these age estimates we produced population age distributions, which were analyzed for evidence of past disturbance. Our approach allowed us to reconstruct patterns of tree establishment over a period of around 250 years. In Bolivia, we found continuous regeneration rates of three species and a peaked age distribution of a long-lived pioneer species. In both Cameroon and Thailand we found irregular age distributions, indicating strongly reduced regeneration rates over a period of 10–60 years. Past fires, windthrow events or anthropogenic disturbances all provide plausible explanations for the reported variation in tree age across the three sites. Our results support the recent idea that the long-term dynamics of tropical forests are impacted by large-scale disturbance-recovery cycles, similar to those driving temperate forest dynamics. PMID:28105034

  4. Size effects on miniature Stirling cycle cryocoolers

    Science.gov (United States)

    Yang, Xiaoqin; Chung, J. N.

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones.

  5. Size effects on miniature Stirling cycle cryocoolers

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoqin Yang; Chung, J.N. [Florida Univ., Dept. of Mechanical and Aerospace Engineering, Gainesville, FL (United States)

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones. (Author)

  6. Plasma Ghrelin Concentrations Were Altered with Oestrous Cycle Stage and Increasing Age in Reproductively Competent Wistar Females

    Science.gov (United States)

    Saffrey, M. Jill; Taylor, Victoria J.

    2016-01-01

    Changes in appetite occur during the ovarian cycle in female mammals. Research on appetite-regulatory gastrointestinal peptides in females is limited, because reproductive changes in steroid hormones present additional experimental factors to control for. This study aimed to explore possible changes in the orexigenic (appetite-stimulating) gastrointestinal peptide hormone ghrelin during the rodent oestrous cycle. Fed and fasted plasma and stomach tissue samples were taken from female Wistar rats (32–44 weeks of age) at each stage of the oestrous cycle for total ghrelin quantification using radioimmunoassay. Sampling occurred during the dark phase when most eating takes place in rats. Statistical analysis was by paired-samples t-test, one-way ANOVA on normally distributed data, with Tukey post-hoc tests, or Kruskal-Wallis if not. GLM univariate analysis was used to assess main effects and interactions in ghrelin concentrations in the fed or fasted state and during different stages of the ovarian cycle, with age as a covariate. No consistent fed to fasted ghrelin increases were measured in matched plasma samples from the same animals, contrary to expectations. Total ghrelin concentrations did not significantly change between cycle stages with ANOVA, in either fed or fasted plasma or in stomach tissue. This was despite significantly decreased fasted stomach contents at oestrus (P = 0.028), suggesting decreased food intake. There was however a significant interaction in ghrelin plasma concentrations between fed and fasted proestrus rats and a direct effect of age with rats over 37 weeks old having lower circulating concentrations of ghrelin in both fed and fasted states. The biological implications of altered ghrelin plasma concentrations from 37 weeks of age are as yet unknown, but warrant further investigation. Exploring peripheral ghrelin regulatory factor changes with increasing age in reproductively competent females may bring to light potential effects on

  7. Ageing of rice husk biochar along a freeze-thaw cycles

    OpenAIRE

    Miao Wei; Cheng Xiao Ying; Meng Jun; Tang Liang

    2016-01-01

    In order to elucidate the aging possess of biochar, the experiment with treatment biochar with soil were performed. For accelerating aging process, freeing-thawing cycle were conducted to simulate the changing process of the physical and chemical properties of biochar and explore the roles of biochar in the changes of the soil nutrition. Aging treatment has a significant impact on the physical and chemical properties of biochar. The pH values, element composition, oxidation of the surface, ab...

  8. Association between the number ofin vitro fertilization cycles and age at menopause

    Institute of Scientific and Technical Information of China (English)

    Philipp Pecnik; Gunda Poschalko; Alexander Just; Eva-Maria Fischer; Johannes Ott

    2012-01-01

    Objective:To assess the association of the number ofin-vitro fertilization(IVF) cycles and the age at menopause.Methods:A total of65 women who underwentIVF treatment in the years 1992-1995 were included and a questionnaire was performed.Results:Thirty-two women had spontaneously become menopausal until follow-up evaluation.Women who had undergone≥6 IVF-cycles had entered menopause significantly earlier than those who had undergone≤5 cycles [(46.9±1.8) years,n=11vs.(49.9±2.9) years,n=21;P=0.03)].Conclusions:Our data demonstrate a link between increasing number ofIVF cycles and ovarian aging.A direct influence ofIVF stimulation, the quality of oocytes at the time ofIVF as well as genetic factors might contribute to this phenomenon.

  9. Release of aged 14C-atrazine residues from soil facilitated by dry-wet cycles

    Science.gov (United States)

    Jablonowski, N. D.; Yu, K.; Koeppchen, S.; Burauel, P.

    2012-04-01

    Intermittent dry-wet cycles may have an important effect on soil structure and aged pesticide residues release (1). A laboratory study was conducted to assess the maximum potential of water extractable aged atrazine residues influenced by soil drying and wetting. The used soil was obtained from an outdoor lysimeter (gleyic cambisol; Corg: 1.45%), containing environmentally aged (22 years) 14C-atrazine residues. For the experiment, soil from 0-10 cm depth was used since most residual 14C activity was previously found in this layer (2,3). Triplicate soil samples with a residual water content of approx. 8% were either dried (45° C) prior water addition or directly mixed with distilled water (soil+water: 1+2, w:w). The samples were shaken (150 rmp, 60 min, at 21° C), centrifuged (approx. 2000 g), and the supernatants were filtered. Water-extracted residual 14C activity was detected via liquid scintillation counter. The total water-extracted 14C activity (the amount of residual 14C activity in a sample equals 100%) was significantly higher (p

  10. Effectiveness and safety of dydrogesterone in regularization of menstrual cycle: a post-marketing study.

    Science.gov (United States)

    Trivedi, Nilesh; Chauhan, Naveen; Vaidya, Vishal

    2016-08-01

    Oral administration of dydrogesterone during second half of menstrual cycle has been shown to reduce menstrual irregularities. This prospective, observational study aimed to determine continued effectiveness of dydrogesterone (prescribed between 1 and 6 cycles or longer) in menstrual cycle regularization in Indian women aged ≥18 years with irregular menstrual cycle for at least 3 months. Those achieving regular cycles (21 to 35 days, inclusive) during treatment were followed up for 6 months after cessation of dydrogesterone treatment. Of the 910 women completing dydrogesterone treatment, 880 (96.7%) achieved cycle regularization (pevent (appendicitis) and three non-serious adverse events were reported. Dydrogesterone regularizes and improves the duration of the menstrual cycle, reduces the amount of bleeding, relieves menstrual pain and prevents relapse of irregular cycles at six months after discontinuation of treatment.

  11. Effects of Indoor Cycling Associated with Diet on Body Composition and Serum Lipids

    Science.gov (United States)

    do Valle, Valeria S.; de Mello, Danielli B.; Fortes, Marcos de Sa R.; Dantas, Estelio H. M.

    2009-01-01

    Study aim: To determine the effects of indoor cycling training combined with restricted diet, lasting 12 weeks, on serum lipid concentrations in obese women. Material and methods: Twenty women aged 23.8 [plus or minus] 3.6 years were randomly assigned into two groups: control (C) and experimental (E), the latter subjected to indoor cycling at…

  12. Stretch-shortening cycle muscle power in women and men aged 18-81 years

    DEFF Research Database (Denmark)

    Edwén, C E; Thorlund, Jonas Bloch; Magnusson, Stig Peter;

    2014-01-01

    This study explored the age-related deterioration in stretch-shortening cycle (SSC) muscle power and concurrent force-velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18-81 years performed maximal countermovement jump...... on an instrumented force plate. Maximal SSC leg extension power expressed per kg body mass (Ppeak) was greater in men than in women across the adult age span (P ......This study explored the age-related deterioration in stretch-shortening cycle (SSC) muscle power and concurrent force-velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18-81 years performed maximal countermovement jumps...

  13. Circadian regulation of cell cycle: Molecular connections between aging and the circadian clock.

    Science.gov (United States)

    Khapre, Rohini V; Samsa, William E; Kondratov, Roman V

    2010-09-01

    The circadian clock generates oscillations in physiology and behavior, known as circadian rhythms. Links between the circadian clock genes Periods, Bmal1, and Cryptochromes and aging and cancer are emerging. Circadian clock gene expression is changed in human pathologies, and transgenic mice with mutations in clock genes develop cancer and premature aging. Control of genome integrity and cell proliferation play key roles in the development of age-associated pathologies and carcinogenesis. Here, we review recent data on the connection between the circadian clock and control of the cell cycle. The circadian clock regulates the activity and expression of several critical cell cycle and cell cycle check-point-related proteins, and in turn cell cycle-associated proteins regulate circadian clock proteins. DNA damage can reset the circadian clock, which provides a molecular mechanism for reciprocal regulation between the circadian clock and the cell cycle. This circadian clock-dependent control of cell proliferation, together with other known physiological functions of the circadian clock such as the control of metabolism, oxidative and genotoxic stress response, and DNA repair, opens new horizons for understanding the mechanisms behind aging and carcinogenesis.

  14. Global Age Distribution of Detrital Zircons, the Supercontinent Cycle, and Subduction Flux Through Time

    Science.gov (United States)

    Bradley, D. C.

    2014-12-01

    The global age distribution of detrital zircons (DZ) tracks the supercontinent cycle. Abundance of zircon ages in modern sands fluctuates through an order of magnitude, with maxima at ca. 2.7, 1.9, 1.0, and 0.45 Ga and minima at ca. 2.3, 1.6, 0.9, 0.7, 0.40, and 0.21 Ga. The age distribution is shaped by differences in zircon production at rifts, arcs, and collisional orogens; by preservation, exhumation, destruction, and recycling of zircons; and by methodological and regional sampling biases. The first-order age maxima and minima have been explained by two largely incompatible models. Model 1 holds that global subduction flux (area subducted per unit time) is constant, that DZ minima reflect destruction of intraoceanic arcs by subduction erosion, and that maxima correspond to times of greater preservation of zircon sources leading up to and during collision. In contrast, Model 2 holds that stepwise changes in global subduction flux—and thus in zircon production at convergent boundaries—are intrinsic to supercontinent cycles. This follows because convergent boundaries are extinguished during collision; hence supercontinent tenures correspond to zircon minima. Examination of >80 geologic secular trends reveals little empirical evidence bearing on these alternatives. The most telling evidence is provided by reconstructed sea levels. Model 1 implies no particular changes in sea level during supercontinent assembly. If plate motion were to cease across a collisional orogen, the same amount of convergence would begin elsewhere and the world population of ridges and ridge volume would be unaffected. In contrast, Model 2 predicts a drop in sea level triggered by supercontinent assembly because death of a collisional plate boundary would mean death of the corresponding ridge and consequent increase in room for seawater in the ocean basins. Reconstructions of global sea level show a major low centered in the Triassic, one that is not linked to glaciation. The sea level

  15. Effective risk management SOGO life cycle management

    OpenAIRE

    Ali, Mohamed Omar

    2012-01-01

    After new or upgrade projects the offshore installation gets maintenance or support through the life cycle management organization at Siemens. Small to medium modification projects are executed by the life cycle management. Risk assessment on these projects show different risks when it comes to estimation and pricing of projects, planning and executing, resource management, competence and knowledge.

  16. Effective risk management SOGO life cycle management

    OpenAIRE

    Ali, Mohamed Omar

    2012-01-01

    After new or upgrade projects the offshore installation gets maintenance or support through the life cycle management organization at Siemens. Small to medium modification projects are executed by the life cycle management. Risk assessment on these projects show different risks when it comes to estimation and pricing of projects, planning and executing, resource management, competence and knowledge.

  17. Stretch-shortening cycle muscle power in women and men aged 18-81 years: Influence of age and gender.

    Science.gov (United States)

    Edwén, C E; Thorlund, J B; Magnusson, S P; Slinde, F; Svantesson, U; Hulthén, L; Aagaard, P

    2014-08-01

    This study explored the age-related deterioration in stretch-shortening cycle (SSC) muscle power and concurrent force-velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18-81 years performed maximal countermovement jumps on an instrumented force plate. Maximal SSC leg extension power expressed per kg body mass (Ppeak) was greater in men than in women across the adult age span (P < 0.001); however, this gender difference was progressively reduced with increasing age, because men showed an ∼50% faster rate of decline in SSC power than women (P < 0.001). Velocity at peak power (VPpeak) was greater in men than in women (P < 0.001) but declined at a greater rate in men than in women (P = 0.002). Vertical ground reaction force at peak power (FPpeak) was higher in men than in women in younger adults only (P < 0.001) and the age-related decline was steeper in men than in women (P < 0.001). Men demonstrated a steeper rate of decline in Ppeak than women with progressive aging. This novel finding emerged as a result of greater age-related losses in men for both force and velocity. Consequently, maximal SSC power production was observed to converge between genders when approaching old age.

  18. Enhancement of volcanism and geothermal heat flux by ice-age cycling: A stress modeling study of Greenland

    Science.gov (United States)

    Stevens, Nathan T.; Parizek, Byron R.; Alley, Richard B.

    2016-08-01

    Ice-age cycling of the Greenland ice sheet likely contributed to locally elevated subglacial geothermal heat fluxes (GHFs), based on recent thermal modeling. Borehole and geophysical data indicate higher GHF in some areas than suggested by current knowledge of underlying geology, particularly at the head of the Northeast Greenland Ice Stream. Changes in lithospheric loading during ice-sheet growth and decay cycles produce large and geologically rapid changes in the effective stress state beneath and near the ice sheet. Oscillations in melt fraction from cyclic loading through multiple ice-age cycles will enhance upward magma migration through the nonlinear increase of melt migration velocity with melt fraction. We simulate periodic ice-sheet loading scenarios along an east-west transect across central Greenland on an Elastic Lithosphere, Relaxed Asthenosphere Earth model. Under likely parameter ranges, deviatoric stresses in the elastic lithosphere across widespread regions are sufficiently high to meaningfully enhance dike emplacement and also allow vug-wave propagation in some scenarios. Stress patterns migrate laterally in response to ice-sheet dynamics, favoring multistage magma ascent. If melt occurs at depth, our modeling suggests that ice-age cycling could help it migrate upward to shallow depth or erupt, contributing to the high observed GHF. Furthermore, shallow magma emplacement might feed hydrothermal systems exploiting enhanced faulting or fracturing from ice-age cycling, adding to elevated GHF. The preglacial passage of the Iceland-Jan Mayen hot spot could have sourced such magmas. Direct observations of these lithospheric processes needed to further constrain our models are limited, highlighting the value of more targeted geophysical studies informing future modeling.

  19. Krebs cycle dysfunction shapes epigenetic landscape of chromatin: novel insights into mitochondrial regulation of aging process.

    Science.gov (United States)

    Salminen, Antero; Kaarniranta, Kai; Hiltunen, Mikko; Kauppinen, Anu

    2014-07-01

    Although there is a substantial literature that mitochondria have a crucial role in the aging process, the mechanism has remained elusive. The role of reactive oxygen species, mitochondrial DNA injuries, and a decline in mitochondrial quality control has been proposed. Emerging studies have demonstrated that Krebs cycle intermediates, 2-oxoglutarate (also known as α-ketoglutarate), succinate and fumarate, can regulate the level of DNA and histone methylation. Moreover, citrate, also a Krebs cycle metabolite, can enhance histone acetylation. Genome-wide screening studies have revealed that the aging process is linked to significant epigenetic changes in the chromatin landscape, e.g. global demethylation of DNA and histones and increase in histone acetylation. Interestingly, recent studies have revealed that the demethylases of DNA (TET1-3) and histone lysines (KDM2-7) are members of 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzymes are activated by oxygen, iron and the major Krebs cycle intermediate, 2-oxoglutarate, whereas they are inhibited by succinate and fumarate. Considering the endosymbiont origin of mitochondria, it is not surprising that Krebs cycle metabolites can control the gene expression of host cell by modifying the epigenetic landscape of chromatin. It seems that age-related disturbances in mitochondrial metabolism can induce epigenetic reprogramming, which promotes the appearance of senescent phenotype and degenerative diseases.

  20. Mechanism of Silicon Electrode Aging upon Cycling in Full Lithium-Ion Batteries.

    Science.gov (United States)

    Delpuech, Nathalie; Dupre, Nicolas; Moreau, Philippe; Bridel, Jean-Sebastian; Gaubicher, Joel; Lestriez, Bernard; Guyomard, Dominique

    2016-04-21

    Understanding the aging mechanism of silicon-based negative electrodes for lithium-ion batteries upon cycling is essential to solve the problem of low coulombic efficiency and capacity fading and further to implement this new high-capacity material in commercial cells. Nevertheless, such studies have so far focused on half cells in which silicon is cycled versus an infinite reservoir of lithium. In the present work, the aging mechanism of silicon-based electrodes is studied upon cycling in a full Li-ion cell configuration with LiCoO2 as the positive electrode. Postmortem analyses of both electrodes clearly indicate that neither one of them contains lithium and that no discernible degradation results from the cycling. The aging mechanism can be explained by the reduction of solvent molecules. Electrons extracted from the positive electrode are responsible for an internal imbalance in the cell, which results in progressive slippage of the electrodes and reduces the compositional range of cyclable lithium ions for both electrodes.

  1. Sensitivity analysis in a life cycle assessment of an aged red wine production from Catalonia, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Meneses, M., E-mail: montse.meneses@uab.cat [Universitat Autònoma de Barcelona, Systems Engineering and Telecomunication Department, ESE, 08193 Bellaterra (Spain); Torres, C.M.; Castells, F. [Universitat Rovira i Virgili, Departament d' Enginyeria Química, Environmental Analysis and Management Group, AGA, Av. Paisos Catalans 26, 43007 Tarragona (Spain)

    2016-08-15

    Sustainability in agriculture and food processing is an issue with a clear growing interest; especially in products were consumers have particular awareness regarding its environmental profile. This is the case of wine industry depending on grape production, winemaking and bottling. Also viticulture and generally agricultural production is significantly affected by climate variations. The aim of this article is to determine the environmental load of an aged red wine from a winery in Catalonia, Spain, over its entire life cycle, including sensitivity analysis of the main parameters related to the cultivation, vinification and bottling. The life cycle assessment (LCA) methodology is used for the environmental analysis. In a first step, life cycle inventory (LCI) data were collected by questionnaires and interviews with the winemaker, all data are actual operating data and all the stages involved in the production have been taken into account (viticulture, vinification, bottling and the disposal subsystem). Data were then used to determine the environmental profile by a life cycle impact assessment using the ReCiPe method. Annual variability in environmental performance, stresses the importance of including timeline analysis in the wine sector. Because of that this study is accompanied with a sensitivity analysis carried out by a Monte Carlo simulation that takes into account the uncertainty and variability of the parameters used. In this manner, the results are presented with confidence intervals to provide a wider view of the environmental issues derived from the activities of the studied wine estate regardless of the eventualities of a specific harvesting year. Since the beverage packaging has an important influence in this case, a dataset for the production of green glass was adapted to reflect the actual recycling situation in Spain. Furthermore, a hypothetical variation of the glass-recycling rate in the glass production completes this article, as a key variable

  2. Deceleration of fusion-fission cycles improves mitochondrial quality control during aging.

    Directory of Open Access Journals (Sweden)

    Marc Thilo Figge

    Full Text Available Mitochondrial dynamics and mitophagy play a key role in ensuring mitochondrial quality control. Impairment thereof was proposed to be causative to neurodegenerative diseases, diabetes, and cancer. Accumulation of mitochondrial dysfunction was further linked to aging. Here we applied a probabilistic modeling approach integrating our current knowledge on mitochondrial biology allowing us to simulate mitochondrial function and quality control during aging in silico. We demonstrate that cycles of fusion and fission and mitophagy indeed are essential for ensuring a high average quality of mitochondria, even under conditions in which random molecular damage is present. Prompted by earlier observations that mitochondrial fission itself can cause a partial drop in mitochondrial membrane potential, we tested the consequences of mitochondrial dynamics being harmful on its own. Next to directly impairing mitochondrial function, pre-existing molecular damage may be propagated and enhanced across the mitochondrial population by content mixing. In this situation, such an infection-like phenomenon impairs mitochondrial quality control progressively. However, when imposing an age-dependent deceleration of cycles of fusion and fission, we observe a delay in the loss of average quality of mitochondria. This provides a rational why fusion and fission rates are reduced during aging and why loss of a mitochondrial fission factor can extend life span in fungi. We propose the 'mitochondrial infectious damage adaptation' (MIDA model according to which a deceleration of fusion-fission cycles reflects a systemic adaptation increasing life span.

  3. Effects of eccentric cycling and endurance training versus low cadence cycling and endurance training on muscle strength and cycling performance in trained individuals

    OpenAIRE

    Eidsheim, Hedda Øyeflaten

    2016-01-01

    Background: Recent studies have shown a positive effect of concurrent strength and endurance training on performance in cycling. Still, few studies have investigated the effect of eccentric cycling (ECC) and low cadence cycling (LCC) on muscle strength and determinants of cycling performance. Aim: Compare the effect of concurrent ECC and endurance training with concurrent LCC and endurance training on strength development, muscle thickness, and cycling performance in trained...

  4. Pacific carbon cycling constrained by organic matter size, age and composition relationships

    Science.gov (United States)

    Walker, Brett D.; Beaupré, Steven R.; Guilderson, Thomas P.; McCarthy, Matthew D.; Druffel, Ellen R. M.

    2016-12-01

    Marine organic matter is one of Earth’s largest actively cycling reservoirs of organic carbon and nitrogen. The processes controlling organic matter production and removal are important for carbon and nitrogen biogeochemical cycles, which regulate climate. However, the many possible cycling mechanisms have hindered our ability to quantify marine organic matter transformation, degradation and turnover rates. Here we analyse existing and new measurements of the carbon:nitrogen ratio and radiocarbon age of organic matter spanning sizes from large particulate organic matter to small dissolved organic molecules. We find that organic matter size is negatively correlated with radiocarbon age and carbon:nitrogen ratios in coastal, surface and deep waters of the Pacific Ocean. Our measurements suggest that organic matter is increasingly chemically degraded as it decreases in size, and that small particles and molecules persist in the ocean longer than their larger counterparts. Based on these correlations, we estimate the production rates of small, biologically recalcitrant dissolved organic matter molecules at 0.11-0.14 Gt of carbon and about 0.005 Gt of nitrogen per year in the deep ocean. Our results suggest that the preferential remineralization of large over small particles and molecules is a key process governing organic matter cycling and deep ocean carbon storage.

  5. On the nature of magnetic cycles at different ages of stars

    CERN Document Server

    Oláh, K; Petrovay, K; Soon, W; Baliunas, S; Kolláth, Z; Vida, K

    2016-01-01

    We study the different patterns of interannual magnetic variability in stars on or near the lower main sequence, approximately solar-type (G-K dwarf) stars in time series of 36 years from the Mount Wilson Observatory Ca\\,{\\sc ii}\\,H\\&K survey. Our main aim is to search for correlations between cycles, activity measures and ages. Time-frequency analysis has been used to discern and reveal patterns and morphology of stellar activity cycles, including multiple and changing cycles, in the datasets. Both the results from short-term Fourier transform and its refinement using the Choi-Williams distribution, with better frequency resolution, are presented in this study. Rotational periods of the stars were derived using multi-frequency Fourier analysis.From the studied 29 stars we found at least one activity cycle on 28 of them. Twelve stars, with longer rotational periods ($39.7\\pm6.0$ days) have simple, smooth cycles, and the rest of the stars, with on-average much faster rotation ($18.1\\pm12.2$ days) show comp...

  6. Hydrologic control of carbon cycling and aged carbon discharge in the Congo River basin

    Science.gov (United States)

    Schefuß, Enno; Eglinton, Timothy I.; Spencer-Jones, Charlotte L.; Rullkötter, Jürgen; de Pol-Holz, Ricardo; Talbot, Helen M.; Grootes, Pieter M.; Schneider, Ralph R.

    2016-09-01

    The age of organic material discharged by rivers provides information about its sources and carbon cycling processes within watersheds. Although elevated ages in fluvially transported organic matter are usually explained by erosion of soils and sedimentary deposits, it is commonly assumed that mainly young organic material is discharged from flat tropical watersheds due to their extensive plant cover and rapid carbon turnover. Here we present compound-specific radiocarbon data of terrigenous organic fractions from a sedimentary archive offshore the Congo River, in conjunction with molecular markers for methane-producing land cover reflecting wetland extent. We find that the Congo River has been discharging aged organic matter for several thousand years, with apparently increasing ages from the mid- to the Late Holocene. This suggests that aged organic matter in modern samples is concealed by radiocarbon from atmospheric nuclear weapons testing. By comparison to indicators for past rainfall changes we detect a systematic control of organic matter sequestration and release by continental hydrology, mediating temporary carbon storage in wetlands. As aridification also leads to exposure and rapid remineralization of large amounts of previously stored labile organic matter, we infer that this process may cause a profound direct climate feedback that is at present underestimated in carbon cycle assessments.

  7. Decline of Phosphotransfer and Substrate Supply Metabolic Circuits Hinders ATP Cycling in Aging Myocardium.

    Directory of Open Access Journals (Sweden)

    Emirhan Nemutlu

    Full Text Available Integration of mitochondria with cytosolic ATP-consuming/ATP-sensing and substrate supply processes is critical for muscle bioenergetics and electrical activity. Whether age-dependent muscle weakness and increased electrical instability depends on perturbations in cellular energetic circuits is unknown. To define energetic remodeling of aged atrial myocardium we tracked dynamics of ATP synthesis-utilization, substrate supply, and phosphotransfer circuits through adenylate kinase (AK, creatine kinase (CK, and glycolytic/glycogenolytic pathways using 18O stable isotope-based phosphometabolomic technology. Samples of intact atrial myocardium from adult and aged rats were subjected to 18O-labeling procedure at resting basal state, and analyzed using the 18O-assisted HPLC-GC/MS technique. Characteristics for aging atria were lower inorganic phosphate Pi[18O], γ-ATP[18O], β-ADP[18O], and creatine phosphate CrP[18O] 18O-labeling rates indicating diminished ATP utilization-synthesis and AK and CK phosphotransfer fluxes. Shift in dynamics of glycolytic phosphotransfer was reflected in the diminished G6P[18O] turnover with relatively constant glycogenolytic flux or G1P[18O] 18O-labeling. Labeling of G3P[18O], an indicator of G3P-shuttle activity and substrate supply to mitochondria, was depressed in aged myocardium. Aged atrial myocardium displayed reduced incorporation of 18O into second (18O2, third (18O3, and fourth (18O4 positions of Pi[18O] and a lower Pi[18O]/γ-ATP[18 O]-labeling ratio, indicating delayed energetic communication and ATP cycling between mitochondria and cellular ATPases. Adrenergic stress alleviated diminished CK flux, AK catalyzed β-ATP turnover and energetic communication in aging atria. Thus, 18O-assisted phosphometabolomics uncovered simultaneous phosphotransfer through AK, CK, and glycolytic pathways and G3P substrate shuttle deficits hindering energetic communication and ATP cycling, which may underlie energetic

  8. Sensitivity analysis in a life cycle assessment of an aged red wine production from Catalonia, Spain.

    Science.gov (United States)

    Meneses, M; Torres, C M; Castells, F

    2016-08-15

    Sustainability in agriculture and food processing is an issue with a clear growing interest; especially in products were consumers have particular awareness regarding its environmental profile. This is the case of wine industry depending on grape production, winemaking and bottling. Also viticulture and generally agricultural production is significantly affected by climate variations. The aim of this article is to determine the environmental load of an aged red wine from a winery in Catalonia, Spain, over its entire life cycle, including sensitivity analysis of the main parameters related to the cultivation, vinification and bottling. The life cycle assessment (LCA) methodology is used for the environmental analysis. In a first step, life cycle inventory (LCI) data were collected by questionnaires and interviews with the winemaker, all data are actual operating data and all the stages involved in the production have been taken into account (viticulture, vinification, bottling and the disposal subsystem). Data were then used to determine the environmental profile by a life cycle impact assessment using the ReCiPe method. Annual variability in environmental performance, stresses the importance of including timeline analysis in the wine sector. Because of that this study is accompanied with a sensitivity analysis carried out by a Monte Carlo simulation that takes into account the uncertainty and variability of the parameters used. In this manner, the results are presented with confidence intervals to provide a wider view of the environmental issues derived from the activities of the studied wine estate regardless of the eventualities of a specific harvesting year. Since the beverage packaging has an important influence in this case, a dataset for the production of green glass was adapted to reflect the actual recycling situation in Spain. Furthermore, a hypothetical variation of the glass-recycling rate in the glass production completes this article, as a key variable

  9. Aging women with polycystic ovary syndrome who achieve regular menstrual cycles have a smaller follicle cohort than those who continue to have irregular cycles

    NARCIS (Netherlands)

    Elting, Mariet W.; Kwee, Janet; Korsen, Ted J.M.; Rekers-Mombarg, Lyset T.M.; Schoemaker, Joop

    2003-01-01

    To examine whether follicle loss due to ovarian aging is responsible for the occurrence of regular menstrual cycles in aging women with polycystic ovary syndrome (PCOS), the size of the FSH-sensitive follicle cohort was estimated by the exogenous follicle-stimulating hormone ovarian reserve test (EF

  10. Recovery from Age-Related Infertility under Environmental Light-Dark Cycles Adjusted to the Intrinsic Circadian Period

    Directory of Open Access Journals (Sweden)

    Nana N. Takasu

    2015-09-01

    Full Text Available Female reproductive function changes during aging with the estrous cycle becoming more irregular during the transition to menopause. We found that intermittent shifts of the light-dark cycle disrupted regularity of estrous cycles in middle-aged female mice, whose estrous cycles were regular under unperturbed 24-hr light-dark cycles. Although female mice deficient in Cry1 or Cry2, the core components of the molecular circadian clock, exhibited regular estrous cycles during youth, they showed accelerated senescence characterized by irregular and unstable estrous cycles and resultant infertility in middle age. Notably, tuning the period length of the environmental light-dark cycles closely to the endogenous one inherent in the Cry-deficient females restored the regularity of the estrous cycles and, consequently, improved fertility in middle age. These results suggest that reproductive potential can be strongly influenced by age-related changes in the circadian system and normal reproductive functioning can be rescued by the manipulation of environmental timing signals.

  11. Recovery from Age-Related Infertility under Environmental Light-Dark Cycles Adjusted to the Intrinsic Circadian Period.

    Science.gov (United States)

    Takasu, Nana N; Nakamura, Takahiro J; Tokuda, Isao T; Todo, Takeshi; Block, Gene D; Nakamura, Wataru

    2015-09-01

    Female reproductive function changes during aging with the estrous cycle becoming more irregular during the transition to menopause. We found that intermittent shifts of the light-dark cycle disrupted regularity of estrous cycles in middle-aged female mice, whose estrous cycles were regular under unperturbed 24-hr light-dark cycles. Although female mice deficient in Cry1 or Cry2, the core components of the molecular circadian clock, exhibited regular estrous cycles during youth, they showed accelerated senescence characterized by irregular and unstable estrous cycles and resultant infertility in middle age. Notably, tuning the period length of the environmental light-dark cycles closely to the endogenous one inherent in the Cry-deficient females restored the regularity of the estrous cycles and, consequently, improved fertility in middle age. These results suggest that reproductive potential can be strongly influenced by age-related changes in the circadian system and normal reproductive functioning can be rescued by the manipulation of environmental timing signals.

  12. THERMAL CYCLING UNDER LOADING OF SINGLE CRYSTAL Cu-Al-Ni AFTER AGING

    Directory of Open Access Journals (Sweden)

    Ignacio Corro

    2016-06-01

    Full Text Available In this paper, a study of single crystal Cu-14.3Al-4.1Ni (%wt subjected to thermal cycling under loading is presented. Shape memory Cu-Al-Ni has low diffusion at temperatures above room temperature. Therefore, it is interesting to know your answer in working conditions and after being aged in this temperature range. Specimens were characterized before and after aging, using a device designed by the authors. Parameters such as critical temperatures and hysteresis width, the repeatability of the curves and the type of TM induced were analyzed. These parameters have changes then the aging or contribute to that may influence the design of applications.

  13. Glutathione maintenance mitigates age-related susceptibility to redox cycling agents

    Directory of Open Access Journals (Sweden)

    Nicholas O. Thomas

    2016-12-01

    Full Text Available Isolated hepatocytes from young (4–6 mo and old (24–26 mo F344 rats were exposed to increasing concentrations of menadione, a vitamin K derivative and redox cycling agent, to determine whether the age-related decline in Nrf2-mediated detoxification defenses resulted in heightened susceptibility to xenobiotic insult. An LC50 for each age group was established, which showed that aging resulted in a nearly 2-fold increase in susceptibility to menadione (LC50 for young: 405 μM; LC50 for old: 275 μM. Examination of the known Nrf2-regulated pathways associated with menadione detoxification revealed, surprisingly, that NAD(PH: quinone oxido-reductase 1 (NQO1 protein levels and activity were induced 9-fold and 4-fold with age, respectively (p=0.0019 and p=0.018; N=3, but glutathione peroxidase 4 (GPX4 declined by 70% (p=0.0043; N=3. These results indicate toxicity may stem from vulnerability to lipid peroxidation instead of inadequate reduction of menadione semi-quinone. Lipid peroxidation was 2-fold higher, and GSH declined by a 3-fold greater margin in old versus young rat cells given 300 µM menadione (p2-fold reduction in cell death, suggesting that the age-related increase in menadione susceptibility likely stems from attenuated GSH-dependent defenses. This data identifies cellular targets for intervention in order to limit age-related toxicological insults to menadione and potentially other redox cycling compounds.

  14. Frequencies of solar activity in laminated anhydrite of Upper Permian age (Zechstein-cycle 2)

    Science.gov (United States)

    Hiete, M.; Berner, U.

    2003-04-01

    Upper Permian Zechstein contains seven evaporitic cycles that were deposited in an epicontinental sea expanding from E-England to Poland. Zechstein-cycles 1 to 3 show a sequence of marine pelite, overlain by marine carbonate and evaporites (in the order sulfate, halite containing possibly anhydrite and potassium salts, and regressive sulphate at the top). Whereas the marginal facies of the lower sulphate horizon of Zechstein-cycle 2 (Stassfurt cycle) consists of massive anhydrite, its basin facies shows in the lower part a fine lamination of white anhydrite alternating with thin black organic carbon rich layers. These laminations are supposed to be annually deposited layers. The black laminae originate from the annual bloom of algae. Layer thickness is about 0.4 to 1.0 mm and increases from basin centre to more marginal positions. The individual layers can be traced over 300 km within the NW-German Basin. The previously described variability of layer thickness requires a forcing mechanism that is effective over long distances and must be also highly periodic. Also, varying layer thicknesses indicate varying anhydrite precipitation, i. e. probably changes in water temperatures which in turn point to climatic influences on the deposition of the layers. Here we re-examined records of cycle thickness (up to 700 laminae) determined by G. Richter-Bernburg in the 1950ties using modern techniques of time series analysis, e. g. wavelet analysis. We could detect cycles with periods of 10-14 years and 90 years which are close to known cycles of solar activity.

  15. Trends in Triathlon Performance: Effects of Sex and Age.

    Science.gov (United States)

    Lepers, Romuald; Knechtle, Beat; Stapley, Paul J

    2013-09-01

    The influences of sex and age upon endurance performance have previously been documented for both running and swimming. A number of recent studies have investigated how sex and age influence triathlon performance, a sport that combines three disciplines (swimming, cycling and running), with competitions commonly lasting between 2 (short distance: 1.5-km swim, 40-km cycle and 10-km run) and 8 h (Ironman distance: 3.8-km swim,180-km cycle and 42-km run) for elite triathletes. Age and sex influences upon performance have also been investigated for ultra-triathlons, with distances corresponding to several Ironman distances and lasting several days, and for off-road triathlons combining swimming, mountain biking and trail running. Triathlon represents an intriguing alternative model for analysing the effects of age and sex upon endurance and ultra-endurance ([6 h) performance because sex differences and age-related declines in performance can be analysed in the same individuals across the three separate disciplines. The relative participation of both females and masters athletes (age[40 years) in triathlon has increased consistently over the past 25 years. Sex differences in triathlon performance are also known to differ between the modes of locomotion adopted (swimming, cycling or running) for both elite and non-elite triathletes. Generally, time differences between sexes in swimming have been shown to be smaller on average than during cycling and running. Both physiological and morphological factors contribute to explaining these findings. Performance density (i.e. the time difference between the winner and tenth-placed competitor) has progressively improved (time differences have decreased) for international races over the past two decades for both males and females, with performance density now very similar for both sexes. For age-group triathletes, sex differences in total triathlon performance time increases with age. However,the possible difference in age

  16. Addressing the effect of social life cycle assessments

    DEFF Research Database (Denmark)

    Jørgensen, Andreas; Dreyer, Louise Camilla; Wangel, Arne

    2012-01-01

    Purpose: In the recently published ‘Guidelines for social life cycle assessment of products’, it is stated that the ultimate objective of developing the social life cycle assessment (SLCA) is to promote improvements of social conditions for the stakeholders in the life cycle. This article addresses...... how the SLCA should be developed so that its use promotes these improvements. Methods: Hypotheses of how the use of SLCA can promote improvement of social conditions in the life cycle are formulated, after which theories and empirical findings from relevant fields of research are used to address...... the validity of these hypotheses. Results: Three in some cases potentially overlapping SLCA approaches are presented, assumed to create a beneficial effect in the life cycle in different ways. However, empirical and theoretical findings show that the beneficial effects proposed to arise from the use of each...

  17. Transport attitudes, residential preferences, and urban form effects on cycling and car use

    DEFF Research Database (Denmark)

    (age 16-74) was conducted in fall 2011 – including socio-economic, demographic, attitude, policy, and residential preference measures. Measures of urban form within walking range - as well as a larger neighborhood scale were added based on respondents home address. Analysis focused on urban form......Transport attitudes, residential preferences, and urban form effects on cycling and car use. Promotion of walking and cycling is part of policies at multiple levels and reasoned in public health as well as environmental sustainability outcomes. Urban form and neighborhood characteristics...... important in explain cycling and walking – than in explaining car use. Geographical scale differences and differences in the importance of urban form points to indirect relations between levels of cycling/walking and levels of car use. Cycling may be encouraged by urban form without substituting car use...

  18. Incidences of menstrual cycle abnormalities in adolescence, and matches between the age at menarche and the development of menstrual cycle abnormalities.

    Science.gov (United States)

    Art, Mercedes Juliana; Doerfler, Daniela

    2010-08-01

    In this study the clinical data of all girls who visited the ambulance for paediatric and adolescent gynaecology at the university clinic for gynaecology and obstetrics in Vienna between 2001 and 2008 because of menstrual cycle abnormalities were used (n = 255). Most frequently, the girls suffered from dysmenorrhoea (29%), tempoanomaly (24%) and metrorrhagia (19%). For 57%, it was possible to find an underlying cause, mainly (24%) a hormonal one. The therapy was in 54% of all cases hormonal. In a second step, the study analyses matches between the age at menarche and the development of menstrual cycle abnormalities. Girls with primary amenorrhoea were excluded (n = 219). The study shows that every age of menarche has its special kind of menstrual cycle abnormality. Only if the menarche had set in at the age of 16, two kinds were named with equal frequency.

  19. Pension Funds' Asset Allocation and Participant Age : A Test of the Life-Cycle Model

    NARCIS (Netherlands)

    Bikker, J.A.; Broeders, D.W.G.A.; Hollanders, D.A.; Ponds, E.H.M.

    2009-01-01

    This paper examines the impact of participants’ age distribution on the asset allocation of Dutch pension funds, using a unique data set of pension fund investment plans for 2007. Theory predicts a negative effect of age on (strategic) equity exposures. We observe that pension funds do indeed take t

  20. Age group, menarche and regularity of menstrual cycles as efficiency predictors in the treatment of overweight.

    Science.gov (United States)

    Kuzmar, Isaac; Cortés, Ernesto; Rizo, Mercedes

    2014-10-30

    To evaluate if there is a relation between age groups, menarche, menstrual cycles and previous pregnancies with the success of weight loss in obese patients at a nutrition clinic. A clinical intervention study was conducted among overweight and obese patients who consulted a nutrition clinic in Barranquilla (Colombia) for the purpose of nutritional assessment. They were subject to a personalized weekly follow-up consultation over the course of 16 weeks in which food consumption patterns, anthropometric measures, body image and self-perception were registered. A total of 135 patients were evaluated. 41 (30,4%) of whom did not complete the study. 69,6% patients did lose weight and 83,7% did lose waist. These losses are lower in older ages (95,5% at. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  1. Effects of Antihormones on the Menstrual cycle

    Institute of Scientific and Technical Information of China (English)

    Marja-LiisaSwahn

    1992-01-01

    The effects of the antiprogestin RU 486 and the anti-estrogen Tamoxifen on theendometrial development may be of importanee for the development of newcontraceptive drugs. of interest in this respect is the anovulatory effect of RU 486during administration in the follicular please but the lon-term effects of continuous proliferative effect have to be clarified the bleding problem after treatment in the secttretory phase is a drawback/or using RU 486 as an anticoneeptive agent in thetuteat phase, but this could be solved by early luteal phase administration. Studies onthe eontraceptive effect afternew after treatment in the early luteal phase are ongoing. The find-ing that anti-estrogen disturbs the endometrial development in a similar pattern as RU 486 may, offer new ahernatives.for contraceptive treattment in the tuteat phase, and thee.effect of combined treatment with antiprogesterone and anti-estrogen deserves to beevaluated.

  2. Adequate dosing of micronutrients for different age groups in the life cycle.

    Science.gov (United States)

    Bienz, Denise; Cori, Hector; Hornig, Dietrich

    2003-09-01

    Many studies of micronutrient supplementation in developing countries have used single-nutrient supplements with either vitamins or minerals. However, people in these countries often suffer from multiple, rather than single, micronutrient deficiencies. The objective of this paper is to discuss the factors that go into determining the adequate dosing of vitamins and/or minerals for people of different ages. To elaborate on the adequacy of micronutrient doses in supplements, a model described by the US FNB was used, which calculates the difference between the mean observed intake for an individual and the estimated average requirement for a life stage and gender group. This model allows estimating the degree of confidence that a certain nutrient intake (from supplements and diet) is adequate. The US/Canadian DRI values have been used as the basis for these calculations, from which it can be concluded that a daily supplement of one RDA of each micronutrient is adequate to cover the personal requirements of all individuals in each respective age and gender group of the population, provided that 20 to 40% of an RDA is supplied by the diet--likely a realistic value for developing countries. DRI values vary significantly between different age groups, reflecting changing needs over a life cycle. With the objective of a supplement to be adequate and safe, the design of a one-for-all supplement covering all age groups is not realistic. Such a supplement would either underscore or surpass the required intake of some of the age groups. Additionally the dosage of certain micronutrients might exceed the upper level of intake for lower age groups. Therefore, it is suggested that three different supplements following the one RDA concept for all micronutrients be developed for research use in developing countries for the following age groups; 1 to 3 years, 4 to 13 years, and females > 14 years (excluding during pregnancy).

  3. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Directory of Open Access Journals (Sweden)

    Pieter Vansteenkiste

    Full Text Available Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  4. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Science.gov (United States)

    Vansteenkiste, Pieter; Van Hamme, David; Veelaert, Peter; Philippaerts, Renaat; Cardon, Greet; Lenoir, Matthieu

    2014-01-01

    Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  5. Anti cancer effects of curcumin: cycle of life and death

    Directory of Open Access Journals (Sweden)

    Das Tanya

    2008-10-01

    Full Text Available Abstract Increasing knowledge on the cell cycle deregulations in cancers has promoted the introduction of phytochemicals, which can either modulate signaling pathways leading to cell cycle regulation or directly alter cell cycle regulatory molecules, in cancer therapy. Most human malignancies are driven by chromosomal translocations or other genetic alterations that directly affect the function of critical cell cycle proteins such as cyclins as well as tumor suppressors, e.g., p53. In this respect, cell cycle regulation and its modulation by curcumin are gaining widespread attention in recent years. Extensive research has addressed the chemotherapeutic potential of curcumin (diferuloylmethane, a relatively non-toxic plant derived polyphenol. The mechanisms implicated are diverse and appear to involve a combination of cell signaling pathways at multiple levels. In the present review we discuss how alterations in the cell cycle control contribute to the malignant transformation and provide an overview of how curcumin targets cell cycle regulatory molecules to assert anti-proliferative and/or apoptotic effects in cancer cells. The purpose of the current article is to present an appraisal of the current level of knowledge regarding the potential of curcumin as an agent for the chemoprevention of cancer via an understanding of its mechanism of action at the level of cell cycle regulation. Taken together, this review seeks to summarize the unique properties of curcumin that may be exploited for successful clinical cancer prevention.

  6. Effect of the menstrual cycle and hormonal contraceptives on human papillomavirus detection in young, unscreened women.

    NARCIS (Netherlands)

    Schmeink, C.E.; Massuger, L.F.A.G.; Lenselink, C.H.; Quint, W.G.V.; Melchers, W.J.G.; Bekkers, R.L.M.

    2010-01-01

    OBJECTIVE: To estimate the effect of the menstrual cycle and oral contraceptive pill (OCP) use on the prevalence, incidence, and persistence of human papillomavirus (HPV). METHODS: A longitudinal study was conducted among 2,065 women aged 18-29 years. The women returned a self-collected

  7. Effect of the menstrual cycle and hormonal contraceptives on human papillomavirus detection in young, unscreened women.

    NARCIS (Netherlands)

    Schmeink, C.E.; Massuger, L.F.A.G.; Lenselink, C.H.; Quint, W.G.V.; Melchers, W.J.G.; Bekkers, R.L.M.

    2010-01-01

    OBJECTIVE: To estimate the effect of the menstrual cycle and oral contraceptive pill (OCP) use on the prevalence, incidence, and persistence of human papillomavirus (HPV). METHODS: A longitudinal study was conducted among 2,065 women aged 18-29 years. The women returned a self-collected cervicovagin

  8. Mesnice: Eating meat: A middle age name for winter big fat eating cycle

    Directory of Open Access Journals (Sweden)

    Bojanin Stanoje

    2009-01-01

    Full Text Available This paper discusses the usage and meaning of the expression mesnice, based on the source from the 15th century. This term is related to the period in between Christmas and big fat eating cycle, when it is allowed to consume animal products, especially meat. The research shows an existence of a concept different than those of the Church one, expressed in terms mesopust (meat and siropust (cheese which imply restraint in consuming meat and cheese in a diet. The testimony about the existence of the unique term mesnice, which included the whole period of meat consuming, points out to a significance of the winter big fat eating cycle preceding Great fasting, and which has a special place in the cyclical change of season errands in an agrarian based society. In turn, this allows us to assume the existence of certain behavior and activities such as carnival forms of celebration similar to those in the Catholic environments in the late middle age Europe or much later, in the documented folk inheritance of the 19th and 20th century, which, in turn, could point out to new fields of research in poorly documented folklore of the middle age Serbia. The term mesnice (and meat weeks, much more than the term mesopust, points out to a social significance of the period preceding the Great fasting and its interpretation within a laic culture, folk rituals, celebrations and fun.

  9. On the complex ageing characteristics of high-power LiFePO4/graphite battery cells cycled with high charge and discharge currents

    DEFF Research Database (Denmark)

    Groot, Jens; Swierczynski, Maciej Jozef; Stroe, Ana-Irina

    2015-01-01

    are demanding. The aim of the present work is to quantify the ageing in terms of capacity fade and impedance growth as a function of operating conditions typical to high-power automotive applications; high charge and discharge rate, elevated temperatures and wide state-of-charge windows. The cycle life of 34......Li-ion batteries are known to undergo complex ageing processes, where the operating conditions have a profound and non-linear effect on both calendar life and cycle life. This is especially a challenge for the automotive industry, where the requirements on product lifetime and reliability...... power-optimised LiFePO4/graphite cells was quantified by testing with charge and discharge rates between 1 and 4C-rate, temperatures between +23o C and +53o C, and a depth-of-discharge of either 100% or 60%. Although all cells show similar ageing pattern in general, the cycle life...

  10. Review of nanomaterial aging and transformations through the life cycle of nano-enhanced products.

    Science.gov (United States)

    Mitrano, Denise M; Motellier, Sylvie; Clavaguera, Simon; Nowack, Bernd

    2015-04-01

    In the context of assessing potential risks of engineered nanoparticles (ENPs), life cycle thinking can represent a holistic view on the impacts of ENPs through the entire value chain of nano-enhanced products from production, through use, and finally to disposal. Exposure to ENPs in consumer or environmental settings may either be to the original, pristine ENPs, or more likely, to ENPs that have been incorporated into products, released, aged and transformed. Here, key product-use related aging and transformation processes affecting ENPs are reviewed. The focus is on processes resulting in ENP release and on the transformation(s) the released particles undergo in the use and disposal phases of its product life cycle for several nanomaterials (Ag, ZnO, TiO2, carbon nanotubes, CeO2, SiO2 etc.). These include photochemical transformations, oxidation and reduction, dissolution, precipitation, adsorption and desorption, combustion, abrasion and biotransformation, among other biogeochemical processes. To date, few studies have tried to establish what changes the ENPs undergo when they are incorporated into, and released from, products. As a result there is major uncertainty as to the state of many ENPs following their release because much of current testing on pristine ENPs may not be fully relevant for risk assessment purposes. The goal of this present review is therefore to use knowledge on the life cycle of nano-products to derive possible transformations common ENPs in nano-products may undergo based on how these products will be used by the consumer and eventually discarded. By determining specific gaps in knowledge of the ENP transformation process, this approach should prove useful in narrowing the number of physical experiments that need to be conducted and illuminate where more focused effort can be placed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. A hybrid multi-effect distillation and adsorption cycle

    KAUST Repository

    Thu, Kyaw

    2013-04-01

    This paper describes the development of a simple hybrid desalination system of a Multi-Effect Distillation (MED) and an adsorption (AD) cycle operating at sub-atmospheric pressures and temperatures. By hybridizing the conventional MED with an AD cycle, there is a symbiotic enhancement of performances of both cycles. The performance enhancement is attributed to (i) the cascade of adsorbent\\'s regeneration temperature and this extended the usage of thermal energy emanating from the brine heater and (ii) the vapor extraction from the last MED stage by AD cycle which provides the effect of lowering saturation temperatures of all MED stages to the extent of 5°C, resulting in scavenging of heat leaks into the MED stages from the ambient. The combined effects of the hybrid cycles increase the water production capacity of the desalination plant by nearly twofolds.In this paper, we demonstrate a hybrid cycle by simulating an 8-stage MED cycle which is coupled to an adsorption cycle for direct vapor extraction from the last MED stage. The sorption properties of silica gel is utilized (acting as a mechanical vapor compressor) to reduce the saturation temperatures of MED stages. The modeling utilizes the adsorption isotherms and kinetics of the adsorbent. +. adsorbate (silica-gel. +. water) pair along with the governing equations of mass, energy and concentration. For a 8-stage MED and AD cycles operating at assorted temperatures of 65-90°C, the results show that the water production rate increases from 60% to twofolds when compared to the MED alone. The performance ratio (PR) and gain output ratio (GOR) also improve significantly. © 2012 Elsevier Ltd.

  12. The age-related performance decline in Ironman triathlon starts earlier in swimming than in cycling and running.

    Science.gov (United States)

    Käch, Ilja; Rüst, Christoph A; Nikolaidis, Pantelis T; Rosemann, Thomas; Knechtle, Beat

    2017-02-21

    In Ironman triathlon, the number of overall male and female finishers increased in the last 30 years, while an improvement in performance has been reported. Studies concluding these numbers only analysed the top ten athletes per age group instead of all finishers, therefore a selection bias might have occurred. The aim of the present study was to investigate participation, performance and the age-related performance decline of all pro and age group triathletes ranked in all Ironman triathlons held worldwide between 2002 and 2015. Split and overall race times of 329,066 (80%) male and 81,815 (20%) female athletes competing in 253 different Ironman triathlon races were analysed. The number of finishers increased in all age groups with exception of women in age group 75-79 years. In pro athletes, performance improved in all disciplines. In age group athletes, performance improved in younger age groups for running (18-24 to 40-44 years) and older age groups for swimming (50-54 to 65-69 years) and cycling (35-39 to 55-59 years), while it impaired in younger age groups for swimming (18-24 to 45-49 years) and cycling (18-24 to 30-34), and older age groups in running (45-49 to 70-74 years). The age-related performance decline started in women in age group 25-29 years in swimming and in age group 30-34 years in cycling, running and overall race time, whereas it started in men in age group 25-29 years in swimming and in age group 35-39 years in cycling, running and overall race time. For athletes and coaches, performance improved in younger age groups for running and older age groups for swimming and cycling and the age-related decline in performance started earlier in swimming than in cycling and running. In summary, women should start competing in Ironman triathlon before the age of 30 years and men before the age of 35 years to achieve their personal best Ironman race time.

  13. The effect of cycling cadence on subsequent 10km running performance in well-trained triathletes.

    Science.gov (United States)

    Tew, Garry

    2005-09-01

    The aim of this study was to examine the effects of different pedalling cadences on the performance of a subsequent 10km treadmill run. Eight male triathletes (age 38.9 ± 15.4 years, body mass 72.2 ± 5.2 kg, and stature 176 ± 6 cm; mean ± SD) completed a maximal cycling test, one isolated run (10km), and then three randomly ordered cycle-run sessions (65 minutes cycling + 10km run). During the cycling bout of the cycle-run sessions, subjects cycled at an intensity corresponding to 70% Pmax while maintaining one of three cadences, corresponding to preferred cadence (PC), PC+15% (fast cadence) and PC-15% (slow cadence). Slow, preferred and fast cadences were 71.8 ± 3.0, 84.5 ± 3.6, and 97.3 ± 4.3 rpm, respectively (mean ± SD). Physiological variables measured during the cycle-run and isolated run sessions were VO2, VE, RER, HR, RPE, and blood lactate. Biomechanical variables measured during the cycle-run and isolated run sessions were running velocity, stride length, stride frequency, and hip and knee angles at foot-strike and toe-off. Running performance times were also recorded. A significant effect of prior cycling exercise was found on 10km running time (p = 0.001) without any cadence effect (p = 0.801, ω(2) = 0.006) (49:58 ± 8:20, 49:09 ± 8:26, 49:28 ± 8:09, and 44:45 ± 6:27 min·s(-1) for the slow, preferred, fast, and isolated run conditions, respectively; mean ± SD). However, during the first 500 m of the run, running velocity was significantly higher after cycling at the preferred and fast cadences than after the slow cadence (p run. However, no significant effect of cycling cadence on running performance was observed within the cadence ranges usually used by triathletes. Key PointsCompared with an isolated run, completion of a cycling event impairs the performance of a subsequent run independently of the pedalling cadence.The choice of cadence within triathletes' usual range does not seem to influence the performance of a 10km run.The results

  14. Effective maintenance practices to manage system aging

    Science.gov (United States)

    Chockie, Alan; Bjorkelo, Kenneth

    A study for the Nuclear Regulatory Commission was recently undertaken to identify effective maintenance practices that could be adapted by the nuclear industry in the United States to assist in managing the aging degradation of plant systems and components. Four organizations were examined to assess the influence of maintenance programs on addressing the system and component aging degradation issues. An effective maintenance program was found to be essential to the management of system and component aging. Four key elements of an effective maintenance program that are important to an aging management were identified: (1) the selection of critical systems and components; (2) the development of an understanding of aging through the collection and analysis of equipment performance information; (3) the development of appropriate preventive and predictive maintenance tasks to manage equipment and system aging degradation; and (4) the use of feedback mechanisms to continuously improve the management of aging systems and components. These elements were found to be common to all four organizations.

  15. Effects of pre-aging treatments on the microstructures and properties before and after paint bake cycle for a 6016 aluminum alloy%预时效对6016铝合金烤漆前后组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    冯佳妮; 陈江华; 刘春辉; 廖元飞; 李祥亮

    2012-01-01

    本文利用显微硬度测试、拉伸试验、差示扫描量热法(DSC)和透射电子显微镜观察,研究了预时效对汽车车身板用6016铝合金烤漆前后微观组织和力学性能的影响.结果表明:经预时效处理的铝合金在室温放置1个月后硬度可保持在65 HV以下,延伸率可保持在25%以上,再经短时间烤漆处理后其硬度和屈服强度分别可提高至100 HV和220 MPa以上.与单级预时效处理后的合金相比,多级预时效处理后的铝合金烤漆前的力学性能更为稳定,烤漆后的硬度和强度更高.6016铝合金快速的烤漆强化效应与预时效处理后合金中形成的细小析出相在烤漆过程中快速长大有关.合金经预时效处理后铝基体内会形成非常细密且与基体完全共格的析出相,其长度约为2~3 nm,而经过烤漆处理后析出相沿〈001〉Al显著增长,长度大于10 nm.高分辨透射电镜分析显示烤漆后样品中形成的是具有单斜结构的针状GP区和β"前驱相.%The effects of pre-aging treatment on the microstructures and mechanical properties before and after paint bake cycle for a 6016 aluminium alloy were investigated by micro-hardness measurement, tensile test, differential scanning calorimetry ( DSC) , and transmission electron microscopy (TEM) . The experimental results show that the hardness and elongation rate of the alloy treated by pre-aging after 1 month's duration at room temperature could remain below 65HV and above 25% , respectively. Then, after paint bake cycle for a short time, the hardness and yield strength increased to over 100HV and 220MPa, respectively. Compared with samples through one-step pre-aging, the stability of the mechanical properties of samples treated by two-step pre-aging were higher, and the hardness and strength after paint bake were even higher. The quick bake hardening response in 6016 alloy was associated with the marked growth of the fine precipitates formed in the pre-aged

  16. Effect of driving cycles on energy efficiency of electric vehicles

    Institute of Scientific and Technical Information of China (English)

    JI FenZhu; XU LiCong; WU ZhiXin

    2009-01-01

    Based on several typical domestic and foreign driving cycles, the energy usage efficiency of the EVs-XL 2000 type electric vehicle (EV) is analyzed.The energy usage efficiency of EVs and the evaluation index of electromotor efficiency are studied.The concepts of "interval usage percentage of energy efficiency" and "exertion degree of energy efficiency" of electromotor are presented.The effects of driving cycles on the distribution of the running status of electromotor and the efficiency are investi-gated.The efficiency of electromotor and the trend of average driving force at different driving cycles are discussed.The exertion degree of energy efficiency and the total power train efficiency of the EVs-XL 2000 type electric vehicle at typical driving cycles are analyzed and calculated.The result in-dicates that the driving cycle engenders a big influence on the exertion degree of electromotor energy efficiency at different driving cycles.Dissimilar driving cycles result in different efficiency distributions of electromotor, the control system as well as the average driving force and driving range are variable.

  17. Effect of driving cycles on energy efficiency of electric vehicles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on several typical domestic and foreign driving cycles, the energy usage efficiency of the EVs-XL 2000 type electric vehicle (EV) is analyzed. The energy usage efficiency of EVs and the evaluation index of electromotor efficiency are studied. The concepts of "interval usage percentage of energy efficiency" and "exertion degree of energy efficiency" of electromotor are presented. The effects of driving cycles on the distribution of the running status of electromotor and the efficiency are investi-gated. The efficiency of electromotor and the trend of average driving force at different driving cycles are discussed. The exertion degree of energy efficiency and the total power train efficiency of the EVs-XL 2000 type electric vehicle at typical driving cycles are analyzed and calculated. The result indicates that the driving cycle engenders a big influence on the exertion degree of electromotor energy efficiency at different driving cycles. Dissimilar driving cycles result in different efficiency distributions of electromotor, the control system as well as the average driving force and driving range are variable.

  18. Associations between Safety from Crime, Cycling, and Obesity in a Dutch Elderly Population: Results from the Longitudinal Aging Study Amsterdam

    Directory of Open Access Journals (Sweden)

    Stef P. J. Kremers

    2012-01-01

    Full Text Available The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were included (age: 63–70 y. Body height and weight were measured using a stadiometer and calibrated weight scale, respectively. Cycling behaviour was assessed in a face-to-face interview, and neighbourhood crime rates were assessed using data from police reports. Men residing in high SES neighbourhoods cycled more than males residing in low SES neighbourhoods. Cycling was negatively related to crime rates among both men and women living in low SES neighbourhoods. Among men living in low SES neighbourhoods, more cycling was associated with lower BMI. Interventions aiming to prevent obesity in older people may consider aiming at increasing bicycle use in lower SES neighbourhoods, but neighbourhood safety issues should be considered.

  19. Associations between safety from crime, cycling, and obesity in a Dutch elderly population: results from the Longitudinal Aging Study Amsterdam.

    Science.gov (United States)

    Kremers, Stef P J; de Bruijn, Gert-Jan; Visscher, Tommy L S; Deeg, Dorly J H; Thomése, G C Fleur; Visser, Marjolein; van Mechelen, Willem; Brug, Johannes

    2012-01-01

    The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES) neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were included (age: 63-70 y). Body height and weight were measured using a stadiometer and calibrated weight scale, respectively. Cycling behaviour was assessed in a face-to-face interview, and neighbourhood crime rates were assessed using data from police reports. Men residing in high SES neighbourhoods cycled more than males residing in low SES neighbourhoods. Cycling was negatively related to crime rates among both men and women living in low SES neighbourhoods. Among men living in low SES neighbourhoods, more cycling was associated with lower BMI. Interventions aiming to prevent obesity in older people may consider aiming at increasing bicycle use in lower SES neighbourhoods, but neighbourhood safety issues should be considered.

  20. Frequency variations of the earth's obliquity and the 100-kyr ice-age cycles

    Science.gov (United States)

    Liu, Han-Shou

    1992-01-01

    Changes in the earth's climate are induced by variations in the earth's orbital parameters which modulate the seasonal distribution of solar radiation. Periodicities in the geological climate record with cycles of 100, 41, and 23 kyr have been linked with changes in obliquity, eccentricity, and precession of the equinoxes. The effect of variations of eccentricity during a 100 kyr period is weak relative to the signals from obliquity and precession variations and it may therefore be expected that the 100 kyr signal in the climate record would be of low intensity. However, this signal dominates the climate record and internal nonlinear processes within the climate system have previously been proposed to account for this fact. The author shows that variations in the frequency of the obliquity cycle can give rise to strong 100-kyr forcing of climate.

  1. Effects of ageing on gastrointestinal motor function

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Graff, Jesper

    2004-01-01

    BACKGROUND: Existing data on the effect of ageing on gastrointestinal motility are few. In this study, we assessed the propulsive effect of all main segments of the gastrointestinal tract in a group of healthy older people. METHODS: 16 healthy volunteers (eight women, eight men) of mean age 81 ye...

  2. Effect of secondary weld thermal cycle on structure and properties

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper deals with structure and impact energy of weld HAZ of 10CrNi3MoV steel after secondary weld thermal cycle (t8/5=8(¨)s~120(¨)s; peak temperature Tm=750℃~1(¨)300℃). It is demonstrated that the coarse grain and structure produced by first thermal cycle keep unchanged after secondary thermal cycle above Ac1 critical temperature but below 1(¨)050(¨)℃. At the same time the low temperature impact energy decreases obviously with increasing t8/5. By metallurgical microscope and transmission electron microscope(TEM) , it is revealed that the effect of coarse grain and structure caused by secondary thermal cycle on low temperature impact energy.

  3. Incorporation of Half-Cycle Theory Into Ko Aging Theory for Aerostructural Flight-Life Predictions

    Science.gov (United States)

    Ko, William L.; Tran, Van T.; Chen, Tony

    2007-01-01

    The half-cycle crack growth theory was incorporated into the Ko closed-form aging theory to improve accuracy in the predictions of operational flight life of failure-critical aerostructural components. A new crack growth computer program was written for reading the maximum and minimum loads of each half-cycle from the random loading spectra for crack growth calculations and generation of in-flight crack growth curves. The unified theories were then applied to calculate the number of flights (operational life) permitted for B-52B pylon hooks and Pegasus adapter pylon hooks to carry the Hyper-X launching vehicle that air launches the X-43 Hyper-X research vehicle. A crack growth curve for each hook was generated for visual observation of the crack growth behavior during the entire air-launching or captive flight. It was found that taxiing and the takeoff run induced a major portion of the total crack growth per flight. The operational life theory presented can be applied to estimate the service life of any failure-critical structural components.

  4. Age- and gender-related development of stretch shortening cycle during a sub-maximal hopping task

    Directory of Open Access Journals (Sweden)

    G Laffaye

    2016-01-01

    Full Text Available The aim of this study was to analyse the effects of age and gender (and their interaction on a stretch shortening cycle solicited during a hopping task. For this aim, 147 girls and 148 boys aged 11 to 20 years, who were enrolled in middle school or secondary school with no experience in sport activity, or training less than three times per week, performed 3x5 hops in place. Leg-stiffness, jump-height and reactive-strength indices were assessed using an accelerometer (Myotest. The participants were selected in order to form five age groups: 11 12, 13-14, 15-16, 17-18 and 19-20 years. Regression analysis between force and centre of mass displacement revealed spring-mass behavior for all groups (r2=73-89, meaning that beginning at the age of 11 years, children are able to perform complex inter-muscular coordination of the lower limbs, revealing efficient neural control early in childhood. Leg stiffness increased from 24.7 ± 10.6 kN • m-1 at 11-12 years to 44.1 ± 14 kN • m-1 in boys, with a small increase until 16 years (+17% and a large increase between 17 and 20 years (+32.7%. In girls, leg stiffness increased from 26.6 ± 9 kN • m-1 at 11-12 years to 39.4 ± 10.9 kN • m-1 at 19-20 years, with a curious decrease in leg stiffness at 17-18 years, probably due to an increase in the percentage of fat at this age (25%. While no gender effect was found, the reactive-strength index revealed that, from 15-16 years onward, boys were better able to produce high levels of force in a shorter time than girls. The age of 15-16 years is a threshold of maturity and gender differentiation, where the boys investigated are more efficient in the stretch shortening cycle.

  5. Drivers and Effects of Virtual Water Cycling

    Science.gov (United States)

    D'Odorico, P.

    2016-12-01

    The increasing global demand for farmland products by the growing and increasingly burgeoning human population is placing unprecedented pressure on the global agricultural system and its water resources. Many regions of the world that are not self-sufficient because of their chronic water scarcity or lack of suitable agricultural land strongly depend on the importation of agricultural commodities and associated embodied (or "virtual") water. International trade, however, may become unreliable when the supplies in the international food market are scarce. As a result, transboundary investments in agricultural land have become a priority for a number of governments and corporations that are trying to expand their agricultural production while securing good profits. This global "land rush" is often driven by the need for a secure access to water resources for agriculture. The globalization of water and land through trade and foreign land acquisitions is leading to a displacement of land use and a disconnection between human populations and the water resources they rely on. Despite the recognized importance of these phenomena in reshaping the patterns of water dependency through teleconnections between consumer behavior and production areas, their effect on global and regional food security, remains poorly quantified. New teleconnections are also emerging from the increasing water use for energy production. Competition in water use for food and energy security constitutes the core of an emerging debate that is generating new questions on the environmental, ethical, economic, and policy implications of human appropriation of water resources. This lecture will examine the ways societies virtually modify their access to water through trade and foreign land acquisitions to meet their growing food and energy needs.

  6. Inhibition of Krebs cycle and activation of glyoxylate cycle in the course of chronological aging of Saccharomyces cerevisiae. Compensatory role of succinate oxidation.

    Science.gov (United States)

    Samokhvalov, V; Ignatov, V; Kondrashova, M

    2004-01-01

    We investigated oxidative processes in mitochondria of Saccharomyces cerevisiae grown on ethanol in the course of chronological aging. We elaborated a model of chronological aging that avoids the influence of exhaustion of medium, as well as the accumulation of toxic metabolites during aging. A decrease in total respiration of cells and, even more, of the contribution of respiration coupled with ATP-synthesis was observed during aging. Aging is also related with the decrease of the contribution of malonate-insensitive respiration. Activities of citrate-synthase (CS), alpha-ketoglutarate dehydrogenase (KGDH) and malate dehydrogenase (MDH) were threefold decreased. The activity of NADP-dependent isocitrate dehydrogenase (NADP-ICDH) decreased more significantly, while the activity of NAD-dependent isocitrate dehydrogenase (NAD-ICDH) fell even greater, being completely inactivated on the third week of aging. In contrast, succinate dehydrogenase (SDH), enzymes of glyoxylate cycle (GCL) (isocitrate lyase (ICL) and malate synthase (MLS)), and enzymes of ethanol oxidation (alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ACDH)), were activated by 50% or more. The behavior of oxidative enzymes and metabolic pathways are apparently inherent to a more viable, long-lived cells in population, selected in the course of chronological aging. This selection allows cells to reveal the mechanism of their higher viability as caused by shunting of complete Krebs cycle by glyoxylate cycle, with a concomitant increased rate of the most efficient energy source, namely succinate formation and oxidation. Thiobarbituric-reactive species (TAR species) increased during aging. We supposed that to be the immediate cause of damage of a part of yeast population. These data show that a greater succinate contribution to respiration in more active cells is a general property of yeast and animal tissues.

  7. Effects of ageing on gastrointestinal motor function

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Graff, Jesper

    2004-01-01

    BACKGROUND: Existing data on the effect of ageing on gastrointestinal motility are few. In this study, we assessed the propulsive effect of all main segments of the gastrointestinal tract in a group of healthy older people. METHODS: 16 healthy volunteers (eight women, eight men) of mean age 81...... mass index and smoking on the motility variables. The results were compared with data from 16 healthy individuals (eight women, eight men) of mean age 24 years (range 20-30 years). RESULTS: Advanced age did not influence gastric emptying or small intestinal transit rate. Older individuals had a slower...

  8. THE EFFECT OF CYCLING CADENCE ON SUBSEQUENT 10KM RUNNING PERFORMANCE IN WELL-TRAINED TRIATHLETES

    Directory of Open Access Journals (Sweden)

    Garry A. Tew

    2005-09-01

    Full Text Available The aim of this study was to examine the effects of different pedalling cadences on the performance of a subsequent 10km treadmill run. Eight male triathletes (age 38.9 ± 15.4 years, body mass 72.2 ± 5.2 kg, and stature 176 ± 6 cm; mean ± SD completed a maximal cycling test, one isolated run (10km, and then three randomly ordered cycle-run sessions (65 minutes cycling + 10km run. During the cycling bout of the cycle-run sessions, subjects cycled at an intensity corresponding to 70% Pmax while maintaining one of three cadences, corresponding to preferred cadence (PC, PC+15% (fast cadence and PC-15% (slow cadence. Slow, preferred and fast cadences were 71.8 ± 3.0, 84.5 ± 3.6, and 97.3 ± 4.3 rpm, respectively (mean ± SD. Physiological variables measured during the cycle-run and isolated run sessions were VO2, VE, RER, HR, RPE, and blood lactate. Biomechanical variables measured during the cycle-run and isolated run sessions were running velocity, stride length, stride frequency, and hip and knee angles at foot-strike and toe-off. Running performance times were also recorded. A significant effect of prior cycling exercise was found on 10km running time (p = 0.001 without any cadence effect (p = 0.801, ω2 = 0.006 (49:58 ± 8:20, 49:09 ± 8:26, 49:28 ± 8:09, and 44:45 ± 6:27 min·s-1 for the slow, preferred, fast, and isolated run conditions, respectively; mean ± SD. However, during the first 500 m of the run, running velocity was significantly higher after cycling at the preferred and fast cadences than after the slow cadence (p < 0.05. Furthermore, the slow cadence condition was associated with a significantly lower HR (p = 0.012 and VE (p = 0.026 during cycling than in the fast cadence condition. The results confirm the deterioration in running performance completed after the cycling event compared with the isolated run. However, no significant effect of cycling cadence on running performance was observed within the cadence ranges

  9. Life Cycle Assessment of age-related environmental impact of biogenic hydraulic fluids; Life Cycle Assessment der alterungsbedingten Umweltvertraeglichkeit biogener Hydraulik-Schmierstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Bressling, Jana

    2012-07-01

    Biogenic hydraulic fluids, based on synthetic esters (category: HEES), have an excellent environmental profile in the unused state, so that they are typically classified into water hazard class 1 or as ''not hazardous to water''. During storage at room temperature and tribological application, occurring chemical and toxicological changes take no account in the classification of lubricants until now. However, the ageing and oxidation stability gets increasing importance, since it determines the service life of lubricants in tribological systems in addition to the storage time. Since it always comes to direct and uncontrolled entries into the environment in case of accidents or hydraulic leaks, it is essential to assess whether there is an environmental hazard by waste oils. With an increased use of biogenic hydraulic fluids in environmentally sensitive areas, thus the need for an appropriate monitoring and assessment approach as part of a Life Cycle Assessment (LCA). The aquatic and miniaturised test procedures applied in this work with the Water Soluble Fraction (WSF) concept, allows a simple and quick screening of age-related ecotoxic potential of lubricants by oxidative processes and tribological application. For detection of genotoxic potential the umu-test is a suitable indicator test to detect geno- and cytotoxic effects by oxidative reactions. The determination of biodegradability is essential for the assessment of the environmental impact of hydraulic fluids. The optimised biodegradability test system ''O2/CO2-Headspace Test'' has proved itself as a suitable procedure for the investigation of biogenic lubricants within the scope of a LCA and shows therefore a comparable method of the required test procedures for the assignment of ecolabels. In addition, the combination of biological test procedures and chemical analysis allows a comprehensive investigation of effects and causes of age-related changes of hydraulic

  10. Size-resolved measurement of the mixing state of soot in the megacity Beijing, China: diurnal cycle, aging and parameterization

    Directory of Open Access Journals (Sweden)

    Y. F. Cheng

    2012-05-01

    Full Text Available Soot particles are the most efficient light absorbing aerosol species in the atmosphere, playing an important role as a driver of global warming. Their climate effects strongly depend on their mixing state, which significantly changes their light absorbing capability and cloud condensation nuclei (CCN activity. Therefore, knowledge about the mixing state of soot and its aging mechanism becomes an important topic in the atmospheric sciences.

    The size-resolved (30–320 nm diameter mixing state of soot particles in polluted megacity air was measured at a suburban site (Yufa during the CAREBeijing 2006 campaign in Beijing, using a volatility tandem differential mobility analyzer (VTDMA. Particles in this size range with non-volatile residuals at 300 °C were considered to be soot particles. On average, the number fraction of internally mixed soot in total soot particles (Fin, decreased from 0.80 to 0.57 when initial Dp increased from 30 to 320 nm. Further analysis reveals that: (1 Fin was well correlated with the aerosol hygroscopic mixing state measured by a CCN counter. More externally mixed soot particles were observed when particles showed more heterogeneous features with regard to hygroscopicity. (2 Fin had pronounced diurnal cycles. For particles in the accumulation mode (Dp at 100–320 nm, largest Fin were observed at noon time, with "apparent" turnover rates (kex → in up to 7.8% h−1. (3 Fin was subject to competing effects of both aging and emissions. While aging increases Fin by converting externally mixed soot particles into internally mixed ones, emissions tend to reduce Fin by emitting more fresh and externally mixed soot particles. Similar competing effects were also found with air mass age indicators. (4 Under the estimated emission

  11. Size-resolved measurement of the mixing state of soot in the megacity Beijing, China: diurnal cycle, aging and parameterization

    Directory of Open Access Journals (Sweden)

    Y. F. Cheng

    2011-12-01

    Full Text Available Soot particles are regarded as the most efficient light absorbing aerosol species in the atmosphere, playing an important role as a driver of global warming. Their climate effects strongly depend on their mixing state, which significantly changes their light absorbing capability and cloud condensation nuclei (CCN activity. Therefore, knowledge about the mixing state of soot and its aging mechanism becomes an important topic in the atmospheric sciences.

    The size-resolved (30–320 nm diameter mixing state of soot particles in polluted megacity air was measured at a suburban site (Yufa during the CAREBeijing 2006 campaign in Beijing, using a Volatility Tandem Differential Mobility Analyzer (VTDMA. Particles in this size range with non-volatile residuals at 300 °C were considered to be soot particles. On average, the number fraction of internally mixed soot in total soot particles (Fin, decreased from 0.80 to 0.57 when initial Dp increased from 30 nm to 320 nm. Further analysis reveals that: (1 Fin was well correlated with the aerosol hygroscopic mixing state measured by a CCN counter. More externally mixed soot particles were observed when particles showed more heterogeneous features with regard to hygroscopicity. (2 Fin had pronounced diurnal cycles. For particles in the accumulation mode (Dp at 100–320 nm, largest Fin were observed at noon time, with apparent turnover rates (kex → in up to 7.8% h−1. (3 Fin was subject to competing effects of both aging and emissions. While aging increases Fin by converting externally mixed soot particles into internally mixed ones, emissions tend to reduce Fin by emitting more fresh and externally mixed soot particles. Similar competing effects were also found with air mass age indicators. (4 Under

  12. Aconitase is the main functional target of aging in the citric acid cycle of kidney mitochondria from mice

    OpenAIRE

    Yarian, Connie S.; Toroser, Dikran; Sohal, Rajindar S.

    2005-01-01

    The activities of the citric acid cycle enzymes were determined in mitochondria isolated from kidneys of relatively young, middle age, and old mice. Aconitase exhibited the most significant decrease in activity with age. The activity of α-ketoglutarate dehydrogenase exhibited a modest decrease in activity, while NADP+-isocitrate dehydrogenase (NADP+-ICD) activity increased moderately with age. Activities of citrate synthase, NAD+-isocitrate dehydrogenase (NAD+-ICD), succinyl-CoA synthetase (S...

  13. Effect of aging on stem cells

    Science.gov (United States)

    Ahmed, Abu Shufian Ishtiaq; Sheng, Matilda HC; Wasnik, Samiksha; Baylink, David J; Lau, Kin-Hing William

    2017-01-01

    Pluripotent stem cells have the remarkable self-renewal ability and are capable of differentiating into multiple diverse cells. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging-associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging-associated diseases. This review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging-associated stem cell defects.

  14. The Effect of Age on Listening Effort

    Science.gov (United States)

    Degeest, Sofie; Keppler, Hannah; Corthals, Paul

    2015-01-01

    Purpose: The objective of this study was to investigate the effect of age on listening effort. Method: A dual-task paradigm was used to evaluate listening effort in different conditions of background noise. Sixty adults ranging in age from 20 to 77 years were included. A primary speech-recognition task and a secondary memory task were performed…

  15. Effects of sediments on the reproductive cycle of corals.

    Science.gov (United States)

    Jones, R; Ricardo, G F; Negri, A P

    2015-11-15

    Dredging, river plumes and natural resuspension events can release sediments into the water column where they exert a range of effects on underlying communities. In this review we examine possible cause-effect pathways whereby light reduction, elevated suspended sediments and sediment deposition could affect the reproductive cycle and early life histories of corals. The majority of reported or likely effects (30+) were negative, including a suite of previously unrecognized effects on gametes. The length of each phase of the life-cycle was also examined together with analysis of water quality conditions that can occur during a dredging project over equivalent durations, providing a range of environmentally relevant exposure scenarios for future testing. The review emphasizes the need to: (a) accurately quantify exposure conditions, (b) identify the mechanism of any effects in future studies, and (c) recognize the close interlinking of proximate factors which could confound interpretation of studies. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Advertising and price effectiveness over the business cycle

    NARCIS (Netherlands)

    Gijsenberg, Maarten; van Heerde, Harald; Dekimpe, Marnik G.; Steenkamp, Jan-Benedict E. M.

    2009-01-01

    In this study, the authors conduct a systematic investigation on the evolution in the effectiveness of two important marketing mix instruments, advertising and price, over the business cycle. Analyses are based on 163 branded products in 37 mature CPG categories in the UK, and this for a period of

  17. Mood Effects of Alcohol and Expectancies during the Menstrual Cycle.

    Science.gov (United States)

    Adesso, Vincent J.; Freitag, Wendy J.

    This research attempted to develop a profile of women's moods across the menstrual cycle and to determine alcohol's effects upon those moods. The Profile of Mood States was used to measure mood in 96 female college students who were heavy drinkers. Subjects were randomly assigned to the cells of the balanced placebo design with equal numbers in…

  18. Lunar cycle effects on sleep and the file drawer problem

    NARCIS (Netherlands)

    Cordi, M.; Ackermann, S.; Bes, F.W.; Hartmann, F.; Konrad, B.N.; Genzel, L.; Pawlowski, M.; Steiger, A.; Schulz, H.; Rasch, B.; Dresler, M.

    2014-01-01

    Popular beliefs about the influence of the full moon on humans exist, although no solid evidence has so far confirmed these ideas [1]. Cajochen et al.[2] recently presented fascinating data on lunar cycle effects on human sleep. However, in a re-analysis of sleep electroencephalography (EEG) data in

  19. Advertising and price effectiveness over the business cycle

    NARCIS (Netherlands)

    Gijsenberg, Maarten; van Heerde, Harald; Dekimpe, Marnik G.; Steenkamp, Jan-Benedict E. M.

    2009-01-01

    In this study, the authors conduct a systematic investigation on the evolution in the effectiveness of two important marketing mix instruments, advertising and price, over the business cycle. Analyses are based on 163 branded products in 37 mature CPG categories in the UK, and this for a period of 1

  20. Sleep-wake cycle of adolescents in Côte d'Ivoire: influence of age, gender, religion and occupation.

    Science.gov (United States)

    Borchers, Claudia; Randler, Christoph

    2012-12-01

    The human sleep-wake cycle is characterized by significant individual differences. Those differences in the sleep-wake cycle are partially heritable but are also influenced by environmental factors like the light/dark cycle or social habits. In this study we analyse for the first time the sleep-wake rhythm of adolescent pupils and working adolescents in a less industrialised country in West Africa near the equator. The aim of this study was to explore the sleep wake cycle in this geographical region, using Côte d'Ivoire as an example. Data collection took place between 2nd of March and 10th of June 2009. 588 adolescents (338 girls, 250 boys) between 10 and 15 years (mean ± SD: 12.72 ± 1.63) participated in this study. We collected data on the religion of the participants (Christian (N = 159), Muslim (N = 352), other/no religion (N = 77)) and their occupation. Participants were either pupils attending school (N = 336) or adolescents that were already working (N = 252) and not attending school. The interviewer filled in the questionnaire. We found significant effects of age (p religion (p < 0.001) and region (p < 0.001). The midpoint of sleep was on average 1:26 (SD: 00:30) on weekdays and 1:37 (SD: 00:42) on weekend days. There are significant differences between weekdays and weekend days, but these were only small. Sleep duration suggests that adolescents in Côte d'Ivoire may gain sufficient sleep during week and weekend days, and thus, may live more in accordance with their own biological clock than adolescents in the northern hemisphere. In contrast, the data can be interpreted that adolescents live in a permanent 'jetlag'. Factors may be the more continuous light/dark cycle in the tropics, low amount of ambient light and less electricity.

  1. The effect of turbo trainer cycling on pedalling technique and cycling efficiency.

    Science.gov (United States)

    Arkesteijn, M; Hopker, J; Jobson, S A; Passfield, L

    2013-06-01

    Cycling can be performed on the road or indoors on stationary ergometers. The purpose of this study was to investigate differences in cycling efficiency, muscle activity and pedal forces during cycling on a stationary turbo trainer compared with a treadmill. 19 male cyclists cycled on a stationary turbo trainer and on a treadmill at 150, 200 and 250 W. Cycling efficiency was determined using the Douglas bags, muscle activity patterns were determined using surface electromyography and pedal forces were recorded with instrumented pedals. Treadmill cycling induced a larger muscular contribution from Gastrocnemius Lateralis, Biceps Femoris and Gluteus Maximus of respectively 14%, 19% and 10% compared with turbo trainer cycling (pcycling induced larger muscular contribution from Vastus Lateralis, Rectus Femoris and Tibialis Anterior of respectively 7%, 17% and 14% compared with treadmill cycling (pcycling was observed. These results suggest that cycling technique and type of ergometer can be altered without affecting cycling efficiency.

  2. Space weather effects of Cycle 24 SEP events

    Science.gov (United States)

    Cohen, C. M.; Mewaldt, R. A.; Mason, G. M.; Vourlidas, A.

    2012-12-01

    When coronal mass ejections (CMEs) are fast and massive enough they can generate interplanetary shocks that accelerate particles to tens or hundreds of MeV/nucleon. These solar energetic particle (SEP) events are a space weather hazard to astronauts and sensitive space-based equipment. If the CME is directed towards Earth and impacts the magnetosphere it can trigger a geomagnetic storm, resulting in a variety of detrimental effects on communication systems and power grids. Although to date, solar cycle 24 has not produced many large-fluence SEP events nor many geoeffective CMEs, we will compare the activity experienced so far to the most significant events of cycle 23. Possible implications for the remainder of the cycle will also be discussed.

  3. Effects of ageing on gastrointestinal motor function

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Graff, Jesper

    2004-01-01

    BACKGROUND: Existing data on the effect of ageing on gastrointestinal motility are few. In this study, we assessed the propulsive effect of all main segments of the gastrointestinal tract in a group of healthy older people. METHODS: 16 healthy volunteers (eight women, eight men) of mean age 81...... mass index and smoking on the motility variables. The results were compared with data from 16 healthy individuals (eight women, eight men) of mean age 24 years (range 20-30 years). RESULTS: Advanced age did not influence gastric emptying or small intestinal transit rate. Older individuals had a slower.......0022). CONCLUSION: Normal ageing seems to reduce the propulsive capacity of the colon, whereas gastric and small intestinal motility is not affected....

  4. To spatially explicitly quantify the indirect effect of disturbances on carbon cycle of Canada's forests

    Science.gov (United States)

    Chen, W.; Cihlar, J.; Wang, S.; Zhang, Q.; Ung, C.; Price, D.; Fernandes, R.; Fraser, R.

    2001-12-01

    Disturbances (i.e., fire, insects-induced mortality, and harvesting) affect the carbon cycle of forested ecosystems directly in the year of occurrence and indirectly in many years after. For example, forest fire directly releases a fraction of carbon in biomass and forest floor to the atmosphere. The carbon cycle is also affected indirectly by disturbances which set the disturbed stand to age zero. So far, most studies estimate the indirect effect of disturbances on carbon balance at regional to national scales by aggregated forests in a region or a country into a few units, and largely ignoring the effect of spatial heterogeneity of disturbances and environmental factors. Because the effects of disturbances and environmental factors are usually non-linear, ignoring their spatial heterogeneity may introduce large error in the carbon budget estimates. In order to reduce this potential large error, spatially explicit quantification of the indirect effect of disturbances are urgently needed. Spatially explicit estimates of carbon cycle at 1-km resolution also allow direct testing against field measurements, as well as provide essential information for sustainable development of natural resources. To spatially explicitly quantify the indirect effect of disturbances on carbon cycle, we need first to quantify how stand age affects NPP. Our early results indicated the effect of stand age on NPP is species and site quality dependent. Therefore, age-NPP relationships are needed for all major forest species to carry out the spatially explicitly quantification of indirect effect of disturbances. We will derive these age-NPP relationships using existing yield tables, biomass allometric equations, and recent data on fine root and foliage production. To apply these age-NPP relationships, we need geo-spatial information on species, age, and site quality. Several initiatives have been underway to develop these spatial data layers. Because the NPP derived using these age

  5. Effects of Simulated Hypogravity and Diet on Estrous Cycling in Rats

    Science.gov (United States)

    Tou, Janet C.; Grindeland, Richard E.; Baer, Lisa A.; Wade, Charles E.

    2003-01-01

    Environmental factors can disrupt ovulatory cycles. The study objective was to determine the effect of diet and simulated hypogravity on rat estrous cycles. Age 50 d Sprague-Dawley rats were randomly assigned to he fed either a purified or chow diet. Only normal cycling rats were used. Experimental rats (n=9-10/group) were kept as ambulatory controls (AC) or subjected to 40 d simulated hypogravity using a disuse atrophy hindlimb suspension (HLS) model. There was no effect on estrous cycles of AC fed either diet. At day 18, HLS rats fed either diet, had lengthened estrous cycles due to prolonged diestrus. HLS rats fed purified diet also had reduced time in estrus. Plasma estradiol was reduced in HLS rats fed purified diet but there was no effect on progesterone. This may have occurred because blood was collected from rats in estrus. Urinary progesterone collected during initial HLS was elevated in rats fed purified diet. In AC, corticosterone was elevated in chow vs purified diet fed rats. Differences were particularly striking following the application of a stressor with HLS/chow-fed rats displaying an enhanced stress response. Results emphasize the importance of diet selection when measuring endocrine-sensitive endpoints. HLS is a useful model for investigating the effects of environment on reproduction and providing insight about the impact extreme environment such as spaceflight on female reproductive health.

  6. Age Effects in Adaptive Criterion Learning.

    Science.gov (United States)

    Cassidy, Brittany S; Gutchess, Angela H

    2016-11-01

    Although prior work has examined age-related changes to criterion placement and flexibility, no study tested these constructs through a paradigm that employs adaptive feedback to encourage specific criterion changes. The goal of this study was to assess age differences in how young and older adults adapt and shift criteria in recognition memory decisions based on trial-by-trial feedback. Young and older adults completed an adaptive criterion learning paradigm. Over 3 study/test cycles, a biased feedback technique at test encouraged more liberal or strict responding by false-positive feedback toward false alarms or misses. Older adults were more conservative than young, even when feedback first encouraged a liberal response bias, and older adults adaptively placed criteria in response to biased feedback, much like young adults. After first being encouraged to respond conservatively, older adults shifted criteria less than young when feedback encouraged more lenient responding. These findings evidence labile adaptive criteria placement and criteria shifting with age. However, age-related tendencies toward conservative response biases may limit the extent to which criteria can be shifted in a lenient direction. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Effects of eccentric cycle ergometry in alpine skiers.

    Science.gov (United States)

    Gross, M; Lüthy, F; Kroell, J; Müller, E; Hoppeler, H; Vogt, M

    2010-08-01

    Eccentric cycling, where the goal is to resist the pedals, which are driven by a motor, increases muscle strength and size in untrained subjects. We hypothesized that it could also be beneficial for athletes, particularly in alpine skiing, which involves predominantly eccentric contractions at longer muscle lengths. We investigated the effects of replacing part of regular weight training with eccentric cycling in junior male alpine skiers using a matched-pair design. Control subjects ( N=7) executed 1-h weight sessions 3 times per week, which included 4-5 sets of 4 leg exercises. The eccentric group ( N=8) performed only 3 sets, followed by continuous sessions on the eccentric ergometer for the remaining 20 min. After 6 weeks, lean thigh mass increased significantly only in the eccentric group. There was a groupxtime effect on squat-jump height favouring the eccentric group, which also experienced a 6.5% improvement in countermovement-jump height. The ability to finely modulate muscle force during variable eccentric cycling improved 50% (p=0.004) only in the eccentric group. Although eccentric cycling did not significantly enhance isometric leg strength, we believe it is beneficial for alpine skiers because it provides an efficient means for hypertrophy while closely mimicking the type of muscle actions encountered while skiing.

  8. Systematic Effect for an Ultralong Cycle Lithium-Sulfur Battery.

    Science.gov (United States)

    Wu, Feng; Ye, Yusheng; Chen, Renjie; Qian, Ji; Zhao, Teng; Li, Li; Li, Wenhui

    2015-11-11

    Rechargeable lithium-sulfur (Li-S) batteries are attractive candidates for energy storage devices because they have five times the theoretical energy storage of state-of-the-art Li-ion batteries. The main problems plaguing Li-S batteries are poor cycle life and limited rate capability, caused by the insulating nature of S and the shuttle effect associated with the dissolution of intermediate lithium polysulfides. Here, we report the use of biocell-inspired polydopamine (PD) as a coating agent on both the cathode and separator to address these problems (the "systematic effects"). The PD-modified cathode and separator play key roles in facilitating ion diffusion and keeping the cathode structure stable, leading to uniform lithium deposition and a solid electrolyte interphase. As a result, an ultralong cycle performance of more than 3000 cycles, with a capacity fade of only 0.018% per cycle, was achieved at 2 C. It is believed that the systematic modification of the cathode and separator for Li-S batteries is a new strategy for practical applications.

  9. Regularity effect in prospective memory during aging

    Directory of Open Access Journals (Sweden)

    Geoffrey Blondelle

    2016-10-01

    Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

  10. Effects of interactive video game cycling on overweight and obese adolescent health.

    Science.gov (United States)

    Adamo, Kristi B; Rutherford, Jane A; Goldfield, Gary S

    2010-12-01

    The purpose of this study was to examine the efficacy of interactive video game stationary cycling (GameBike) in comparison with stationary cycling to music on adherence, energy expenditure measures, submaximal aerobic fitness, body composition, and cardiovascular disease risk markers in overweight and obese adolescents, using a randomized controlled trial design. Thirty overweight (with at least 1 metabolic complication) or obese adolescents aged 12-17 years were stratified by gender and randomized to video game or music condition, with 4 participants (2 per group) failing to complete the twice weekly 60 min sessions of the 10-week trial. The music group had a higher rate of attendance compared with the video game group (92% vs. 86%, p cycle ergometer protocol. Also, when collapsed, the exercise modalities reduced body fat percentage and total cholesterol. The present study indicates that cycling to music was just as effective as stationary cycling while playing video games at improving fitness, body composition, and cholesterol profiles in overweight and obese teens, and resulted in increased attendance, vigorous intensity of physical activity, and distance pedaled. Therefore, our data support the superiority of cycling to music and indicate investing in the more expensive GameBike may not be worth the cost.

  11. New exposure ages for the Last Glacial Cycle in the Sanabria Lake region (northwestern Spain)

    Science.gov (United States)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; Domínguez-Cuesta, María Jose; Rinterknecht, Vincent; Pallàs, Raimon; Braucher, Régis; Bourlès, Didier; Valero-Garcés, Blas

    2013-04-01

    The Sanabria Lake region is located in the Trevinca Massif, a mid-latitude mountain area up to 2128 m asl in the northwest corner of the Iberian Peninsula (42oN 6oW). An ice cap glaciation took place during the Last Glacial Cycle in this massif, with an equilibrium line altitude of 1687 m for the Tera glacial outlet at its local maximum (Cowton et al., 2009). A well preserved glacial sequence occurs on an area of 45 km2 around the present Sanabria Lake (1000 m asl) and is composed by lateral and end moraines in close relationship with glaciolacustrine deposits. This sequence shows the ice snout oscillations of the former Tera glacier during the Last Glacial Cycle and offers a good opportunity to compare radiocarbon and OSL- based chronological models with new cosmogenic isotope dates. The new dataset of 10Be exposure ages presented here for the Sanabria Lake moraines is based on measurements conducted on 23 boulders and is compared with previous radiocarbon and OSL data conducted on ice related deposits (Pérez-Alberti et al., 2011; Rodríguez-Rodríguez et al., 2011). Our results are coherent with the available deglaciation radiocarbon chronology, and support a last deglaciation origin for the whole set of end moraines that are downstream the Sanabria Lake (19.2 - 15.7 10Be ka). Discrepancies between results of the different dating methods concern the timing of the local glacial maximum, with the cosmogenic exposure method always yielding the youngest minimum ages. As proposed to explain similar observations made elsewhere (Palacios et al., 2012), reconciling the ages from different dating methods would imply the occurrence of two glacial advances close enough in extent to generate an overlapping polygenic moraine. Cowton, T., Hughes, P.D., Gibbard, P.L., 2009. Palaeoglaciation of Parque Natural Lago de Sanabria, northwest Spain. Geomorphology 108, 282-291. Rodríguez-Rodríguez, L., Jiménez-Sánchez, M., Domínguez-Cuesta, M.J., Rico, M.T., Valero-Garcés, B

  12. A maximal cycle test with good validity and high repeatability in adults of all ages

    DEFF Research Database (Denmark)

    Eriksen, L; Tolstrup, J S; Larsen, Steen

    2014-01-01

    In 11 680 individuals (18-85 years) maximal oxygen consumption (VO2max) was estimated indirectly in a maximal cycle test using a prediction model developed in a young population (15-28 years). A subsample of 182 individuals (23-77 years) underwent 2 maximal cycle tests with VO2max estimated...... we suggest a new prediction model of VO2max. The maximal cycle test was highly repeatable....

  13. The effectiveness of community-based cycling promotion: findings from the Cycling Connecting Communities project in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Merom Dafna

    2010-01-01

    Full Text Available Abstract Background Encouraging cycling is an important way to increase physical activity in the community. The Cycling Connecting Communities (CCC Project is a community-based cycling promotion program that included a range of community engagement and social marketing activities, such as organised bike rides and events, cycling skills courses, the distribution of cycling maps of the area and coverage in the local press. The aim of the study was to assess the effectiveness of this program designed to encourage the use of newly completed off-road cycle paths through south west Sydney, Australia. Methods The evaluation used a quasi-experimental design that consisted of a pre- and post-intervention telephone survey (24 months apart of a cohort of residents (n = 909 in the intervention area (n = 520 (Fairfield and Liverpool and a socio-demographically similar comparison area (n = 389 (Bankstown. Both areas had similar bicycle infrastructure. Four bicycle counters were placed on the main bicycle paths in the intervention and comparison areas to monitor daily bicycle use before and after the intervention. Results The telephone survey results showed significantly greater awareness of the Cycling Connecting Communities project (13.5% vs 8.0%, p Conclusion Despite relatively modest resources, the Cycling Connecting Communities project achieved significant increases in bicycle path use, and increased cycling in some sub-groups. However, this community based intervention with limited funding had very limited reach into the community and did not increase population cycling levels.

  14. The effects of cycling shoe stiffness on forefoot pressure.

    Science.gov (United States)

    Jarboe, Nathan Edward; Quesada, Peter M

    2003-10-01

    Plantar pressure data were recorded in two different shoe types to determine the effect of cycling shoe stiffness on peak plantar forefoot pressure in cyclists. Two pairs of shoes of the same size and manufacturer, identical except for outsole material and stiffness, were tested. Shoe stiffness measurements were collected under controlled conditions and in two different configurations using a dynamic hydraulic tensile testing machine. Measurements of plantar pressure were done using Pedar capacitive-based sensor insoles while subjects pedaled in a seated position at a controlled power output. Power output was set at a constant value of 400 W across all subjects by a magnetic resistance trainer unit. The pressure distribution in carbon-fiber-composite shoes during cycling was compared to cycling shoes made with plastic soles. Carbon fiber shoes presented stiffness values 42% and 550% higher than plastic shoes in longitudinal bending and three-point bending, respectively. The shoes made with carbon fiber produced peak plantar pressures 18% higher than those of plastic design (121 kPa vs. 103 kPa, p = .005). Competitive or professional cyclists suffering from metatarsalgia or ischemia should be especially careful when using carbon fiber cycling shoes because the shoes increase peak plantar pressure, which may aggravate these foot conditions.

  15. Associations between safety from crime, cycling, and obesity in a Dutch elderly population: results from the longitudinal aging study Amsterdam

    NARCIS (Netherlands)

    Kremers, S.P.J.; de Bruijn, G.J.; Visscher, T.L.S.; Deeg, D.J.H.; Thomése, G.C.F.; Visser, M.; van Mechelen, W.; Brug, J.

    2012-01-01

    The objective of this cross-sectional study was to investigate differences in associations between crime rates, cycling, and weight status between people living in low and high socioeconomic status (SES) neighbourhoods. In total, 470 participants in the Longitudinal Aging Study Amsterdam were includ

  16. Effects of Biosolids on Carbon Sequestration and Nitrogen Cycling

    OpenAIRE

    Li, Jinling

    2013-01-01

    Land application of biosolids has been demonstrated to improve nutrient availability (mainly N and P) and improve organic matter in soils, but the effects of biosolids on C sequestration and N cycling in the Mid-Atlantic region is not well understood. The objectives were: 1) to investigate soil C sequestration at sites with a long-term history of biosolids either in repeated application or single large application; 2) to characterize and compare soil C chemistry using advanced 13C nuclear mag...

  17. The Effect of Physical Biorhythm Cycle on Some Physical Fitness Factors of Adolescent Volleyball Players

    Directory of Open Access Journals (Sweden)

    Ehsan Zareian

    2014-04-01

    Full Text Available Biorhythm is one of the latest topics in the field of identifying mind’s ergonomics. Of all the performances with which biorhythm deals is the physical performance. The purpose of present research is to study the effect of physical cycle of biorhythm on the designated factors of physical fitness among teenage volleyball players in the city of Qom. In the present field research, 30 people were selected out of volleyball players aged 12 to 15 at random in the city of Qom. Biorhythm cycles were obtained with the biorhythm software. Vertical jump and medicine ball throwing were used as tests associating with muscular power; pull-up and sit-up were used as tests associating with muscular endurance in two states of charged (the second position and discharged (the first position of biorhythm physical cycle. The statistical correlated t test with the significance level of p≤0.05 was used to analyze data. The findings indicated that the tests pertaining to power including Vertical jump and medicine ball throwing were well-correlated with the physical cycle of biorhythm (p=0.042; p=0.019. However, the muscular endurance tests (revised sit-up and pull-up did not show any significant difference between the two states and were not correlated with the physical cycle of biorhythm (p=0.75; p=0.73. The predictions by physical cycle of biorhythm on the muscular power of athletes are correct, but it was not possible with the muscular endurance of athletes. Of course, more researches should be conducted to increase the certainty of correctness predicted by the physical cycle of biorhythm. The prediction of this theory can be used to increase the performances of athletes in sports competitions if the biorhythm cycles prove right.

  18. Formation and aging of secondary organic aerosol from isoprene photooxidation during cloud condensation-evaporation cycles

    Science.gov (United States)

    Giorio, C.; Siekmann, F.; Bregonzio, L.; Temime-Roussel, B.; Ravier, S.; Tapparo, A.; Kalberer, M.; Doussin, J.; Monod, A.

    2013-12-01

    Biogenic volatile organic compounds (BVOCs) can be oxidized in the gas phase to form more water-soluble compounds which could partition into atmospheric water droplets. Oxidation processes in the liquid phase could produce high molecular weight and less volatile compounds which can partly remain in the particle phase after water evaporation (Ervens et al., 2011). This work investigates the formation and composition of secondary organic aerosol (SOA) from the photooxidation of isoprene (the most abundant BVOC) and methacrolein (its main first-generation oxidation product). The experiments were performed during the CUMULUS (CloUd MULtiphase chemistry of organic compoUndS in the troposphere) campaigns at the 4.2 m3 stainless steel CESAM chamber at LISA, specifically designed to investigate multiphase processes (Wang et al., 2011). In each experiment, 500/1000 ppb of isoprene or methacrolein were injected in the chamber together with HONO before irradiation. Gas phase oxidation products have been analyzed on-line by a Proton Transfer Reaction Mass Spectrometer (PTR-MS) and a Fourier Transform Infrared Spectrometer (FTIR) together with NOx and O3 analyzers. SOA formation and composition has been followed on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-Of-Flight Aerosol Mass Spectrometer (HR-TOF-AMS). Particular attention has been focused on the study of SOA formation and aging during cloud condensation-evaporation cycles simulated in the smog chamber. In all experiments, we noted that water soluble gas-phase oxidation products readily partition into cloud droplets accompanied by a prompt SOA production during cloud formation which partly persists after cloud evaporation. Ervens, B. et al. (2011) Atmos. Chem. Phys. 11, 11069 11102. Wang, J. et al. (2011) Atmos. Measur. Tech. 4, 2465 2494.

  19. Effectiveness of BCG vaccination to aged mice

    Directory of Open Access Journals (Sweden)

    Ito Tsukasa

    2010-09-01

    Full Text Available Abstract Background The tuberculosis (TB still increases in the number of new cases, which is estimated to approach 10 million in 2010. The number of aged people has been growing all over the world. Ageing is one of risk factors in tuberculosis because of decreased immune responses in aged people. Mycobacterium bovis Bacillus Calmette Guérin (BCG is a sole vaccine currently used for TB, however, the efficacy of BCG in adults is still a matter of debate. Emerging the multidrug resistant Mycobacterium tuberculosis (MDR-TB make us to see the importance of vaccination against TB in new light. In this study, we evaluated the efficacy of BCG vaccination in aged mice. Results The Th1 responses, interferon-γ production and interleukin 2, in BCG inoculated aged mice (24-month-old were comparable to those of young mice (4- to 6-week-old. The protection activity of BCG in aged mice against Mycobacterium tuberculosis H37Rv was also the same as young mice. Conclusion These findings suggest that vaccination in aged generation is still effective for protection against tuberculosis.

  20. Age and attitude: Changes in cycling patterns of different e-bike user segments

    DEFF Research Database (Denmark)

    Haustein, Sonja; Møller, Mette

    2016-01-01

    -bikes and mainly bought an e-bike to increase cycling frequency; (2) utilitarian e-bikers who already cycled regularly before having access to an e-bike and used the e-bike particularly for practical purposes and to reduce travel time; (3) recreational e-bikers who were very positive about e-bike use but used...

  1. Performance Degradation of Thermal Parameters during Cycle Ageing of High Energy Density Ni-Mn-Co based Lithium-Ion Battery Cells

    DEFF Research Database (Denmark)

    Stanciu, Tiberiu; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

    2016-01-01

    as well, since the thermal management of the battery is crucial for the safety of the EV driver. Moreover, the thermal management system can significantly lower the degradation rate of the battery pack and thus reduce costs. In this paper, the thermal characterization of a commercially available Nickel......-Manganese-Cobalt (NMC) based Li-ion battery cell was performed under different operating conditions: state-of-charge (SOC) levels, charge/discharge current rates and operating temperatures. Moreover, by carrying out accelerated cycle ageing tests on a total of nine NMC-based Li-ion battery cells, the effect of ageing...

  2. Spatial Frequency Discrimination: Effects of Age, Reward, and Practice.

    Science.gov (United States)

    van den Boomen, Carlijn; Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed) in a higher spatial frequency (reference frequency: 6 cycles per degree) discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135). Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28) punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials) and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be used in future

  3. Spatial Frequency Discrimination: Effects of Age, Reward, and Practice

    Science.gov (United States)

    Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed) in a higher spatial frequency (reference frequency: 6 cycles per degree) discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135). Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5–6 year-olds (N = 28) punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5–6 years completed only a fourth or half of the run (64 to 128 out of 254 trials) and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7–12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7–12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be used in

  4. Aconitase is the main functional target of aging in the citric acid cycle of kidney mitochondria from mice.

    Science.gov (United States)

    Yarian, Connie S; Toroser, Dikran; Sohal, Rajindar S

    2006-01-01

    The activities of the citric acid cycle enzymes were determined in mitochondria isolated from kidneys of relatively young, middle age, and old mice. Aconitase exhibited the most significant decrease in activity with age. The activity of alpha-ketoglutarate dehydrogenase exhibited a modest decrease in activity, while NADP(+)-isocitrate dehydrogenase (NADP(+)-ICD) activity increased moderately with age. Activities of citrate synthase, NAD(+)-isocitrate dehydrogenase (NAD(+)-ICD), succinyl-CoA synthetase (SCS), succinate dehydrogenase (SD), fumarase (FUM), and malate dehydrogenase (MD) were not affected. The molar ratio of the intra-mitochondrial redox indicator, NADPH:NADP(+), was higher in young compared to old animals, while the NADH:NAD(+) molar ratio remained unchanged. It is suggested that an age-related decrease in aconitase activity along with relatively subtle alterations in activities of some other citric acid cycle enzymes are likely to contribute to a decline in the overall efficiency of mitochondrial bioenergetics. The biological consequences of such alterations include age-related fluctuations in the citric acid cycle intermediates, which are precursors of protein synthesis, activators of fatty acid synthesis, and can also act as ligands for orphan G-protein coupled receptors.

  5. Biological properties of differently-aged human keratinocytes:population doubling time growth curve and cell cycle analysis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To explore the biological properties of keratinocytes from differently-aged healthy human beings. Methods Keratinocytes from fetus,teenager and middle-aged groups were separated and cultured. The population doubling time (PDT) and cell growth curve in different cells were compared,and the cell cycles were analyzed by flow cytometry. Results ① In primary culture of keratinocytes,the adherence time in middle-aged group was longer than that in fetus and teenager groups. However,all cell morphology sh...

  6. Effect of DUPIC Cycle on CANDU Reactor Safety Parameters

    Directory of Open Access Journals (Sweden)

    Nader M.A. Mohamed

    2016-10-01

    Full Text Available Although, the direct use of spent pressurized water reactor (PWR fuel in CANda Deuterium Uranium (CANDU reactors (DUPIC cycle is still under investigation, DUPIC cycle is a promising method for uranium utilization improvement, for reduction of high level nuclear waste, and for high degree of proliferation resistance. This paper focuses on the effect of DUPIC cycle on CANDU reactor safety parameters. MCNP6 was used for lattice cell simulation of a typical 3,411 MWth PWR fueled by UO2 enriched to 4.5w/o U-235 to calculate the spent fuel inventories after a burnup of 51.7 MWd/kgU. The code was also used to simulate the lattice cell of CANDU-6 reactor fueled with spent fuel after its fabrication into the standard 37-element fuel bundle. It is assumed a 5-year cooling time between the spent fuel discharges from the PWR to the loading into the CANDU-6. The simulation was carried out to calculate the burnup and the effect of DUPIC fuel on: (1 the power distribution amongst the fuel elements of the bundle; (2 the coolant void reactivity; and (3 the reactor point-kinetics parameters.

  7. Effect of DUPIC cycle on CANDU reactor safety parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Nader M. A. [Atomic Energy Authority, ETRR-2, Cairo (Egypt); Badawi, Alya [Dept. of Nuclear and Radiation Engineering, Alexandria University, Alexandria (Egypt)

    2016-10-15

    Although, the direct use of spent pressurized water reactor (PWR) fuel in CANda Deuterium Uranium (CANDU) reactors (DUPIC) cycle is still under investigation, DUPIC cycle is a promising method for uranium utilization improvement, for reduction of high level nuclear waste, and for high degree of proliferation resistance. This paper focuses on the effect of DUPIC cycle on CANDU reactor safety parameters. MCNP6 was used for lattice cell simulation of a typical 3,411 MWth PWR fueled by UO{sub 2} enriched to 4.5w/o U-235 to calculate the spent fuel inventories after a burnup of 51.7 MWd/kgU. The code was also used to simulate the lattice cell of CANDU-6 reactor fueled with spent fuel after its fabrication into the standard 37-element fuel bundle. It is assumed a 5-year cooling time between the spent fuel discharges from the PWR to the loading into the CANDU-6. The simulation was carried out to calculate the burnup and the effect of DUPIC fuel on: (1) the power distribution amongst the fuel elements of the bundle; (2) the coolant void reactivity; and (3) the reactor point-kinetics parameters.

  8. EHR's effect on the revenue cycle management Coding function.

    Science.gov (United States)

    Giannangelo, Kathy; Fenton, Susan

    2008-01-01

    Without administrative terminologies there is no revenue to manage. The use of healthcare IT to capture the codes for administrative and financial support functions will impact the revenue cycle and the management of it. This is presumed to occur because clinical data coded at the point of care becomes the source for claims data. Thus, as electronic health record system applications utilizing terminologies are implemented, healthcare providers need to systematically consider the effect on the coding function and management of the revenue cycle. A key factor is the sequence of events changes, i.e., instead of a health information management professional selecting billing codes at the conclusion of an encounter based on the review of the record, clinical data generates the claims data via mapping. Efficiencies and management challenges result.

  9. Effects of cell cycle noise on excitable gene circuits

    CERN Document Server

    Veliz-Cuba, Alan; Bennett, Matthew R; Josić, Krešimir; Ott, William

    2016-01-01

    We assess the impact of cell cycle noise on gene circuit dynamics. For bistable genetic switches and excitable circuits, we find that transitions between metastable states most likely occur just after cell division and that this concentration effect intensifies in the presence of transcriptional delay. We explain this concentration effect with a 3-states stochastic model. For genetic oscillators, we quantify the temporal correlations between daughter cells induced by cell division. Temporal correlations must be captured properly in order to accurately quantify noise sources within gene networks.

  10. Building effectiveness communication ratios for improved building life cycle management

    Energy Technology Data Exchange (ETDEWEB)

    Morrissey, E.; Keane, M.; McCarthy, J. [Ireland National Univ., Cork (Ireland). IRUSE; O' Donnell, J. [Lawrence Berkely National Laboratory, Berkeley, CA (United States)]|[Ireland National Univ., Cork (Ireland). IRUSE

    2005-07-01

    The construction and operation of buildings consumes 35 per cent of total U.S. energy production. Although the application of building energy simulation models in early design stages can significantly increase performance throughout the building life cycle, energy simulation modeling has not been widely adopted by the design community. The complexity and length of time needed to prepare energy models are considered to be barriers, as well as the lack of energy appraisal tools capable of modeling a wide spectrum of hybrid heating, ventilation and air conditioning (HVAC) systems. A performance-based strategy using building effectiveness communication ratios stored in Building Information Models (BIM) was presented in this paper. The strategy aimed to link currently fragmented stages within the building life cycle. It was suggested that the ability to share and exchange information will reduce the amount of user time required for building simulation models. The proposed Building Energy Monitoring Analyzing and Communication (BEMAC) framework is an integrated environment that allows users to share data with other applications through an integrated data model. The data models allow each participant to employ tools specific to their needs without compromising or corrupting project data. Data values elicited from the model act as best-possible values. It was anticipated that by assigning spaces within the simulation model with proposed HVAC systems, reproductions of the energy use by these mechanical systems can contribute to overall energy data representation and analysis. Idealized Effectiveness Ratios and Performance Effectiveness Ratios were discussed in relation to a case study of the Glucksman Art Gallery at the National University of Ireland. Results indicated that the Idealized Effectiveness Ratio is applicable across the entire building life cycle, while the Performance Effectiveness Ratio allows facility managers to investigate the energy saving potential of the

  11. Age effect on orthodontic tooth movement

    NARCIS (Netherlands)

    Ren, Yijin

    2003-01-01

    This study was performed to investigate the effect of age on the efficiency of orthodontic tooth movement based on critical literature reviews, studies on a standardized orthodontic animal model and a non-invasive clinical investigation. A systematic review was performed on the optimum force for ort

  12. Aerosol indirect effect on biogeochemical cycles and climate.

    Science.gov (United States)

    Mahowald, Natalie

    2011-11-11

    The net effect of anthropogenic aerosols on climate is usually considered the sum of the direct radiative effect of anthropogenic aerosols, plus the indirect effect of these aerosols through aerosol-cloud interactions. However, an additional impact of aerosols on a longer time scale is their indirect effect on climate through biogeochemical feedbacks, largely due to changes in the atmospheric concentration of CO(2). Aerosols can affect land and ocean biogeochemical cycles by physical forcing or by adding nutrients and pollutants to ecosystems. The net biogeochemical effect of aerosols is estimated to be equivalent to a radiative forcing of -0.5 ± 0.4 watts per square meter, which suggests that reaching lower carbon targets will be even costlier than previously estimated.

  13. Genetic and ageing effects on beef quality

    OpenAIRE

    Li, Xin

    2013-01-01

    The overall aim of this thesis was to investigate genetic and ageing effects on beef quality. To study the genetic effects, association analyses were carried out between single nucleotide polymorphisms (SNPs) at DGAT1, LEP, SCD1, CAPN1 and CAST genes with colour, marbling, water holding capacity (WHC) and tenderness in meat from young bulls of the beef cattle population in Sweden. In total 243 young bulls from five beef breeds were included in the analysis. The results confirmed previous...

  14. Relative age effect in junior tennis (male

    Directory of Open Access Journals (Sweden)

    Adrián Agricola

    2013-03-01

    Full Text Available BACKGROUND: The issues of the age effect (the theory of the age influence have been shown in sport sciences since the 1980s. The theory of age effect works on the assumption that athletes born in the beginning of a calendar year are, particularly in children’s and junior age, more successful than athletes born in the end of the year. This fact has been proved by a number of research studies, mainly in ice hockey, soccer, and tennis but also in other sports. OBJECTIVE: The submitted contribution is aimed at verifying of the age effect in junior tennis. The research objective was to find out the distribution of birth date frequencies in a population of tennis players’ in individual months, quarters, and half-years in the observed period 2007–2011 and to check the significance of differences. METHODS: The research was conducted on male tennis players aged 13–14 (N = 239, participants of the World Junior Tennis Finals. From the methodological point of view, it was an intentional selection. The birth dates of individual tennis players were taken from official materials of the ITF, the research data were processed using Microsoft Excel. The personal data were processed with the approval of players and the hosting organization (ITF. RESULTS: Testing of the hypothesis on the significance of differences in the distribution of frequencies between individual quarters (Q1–Q4 has proved statistically relevant differences between Q1 and Q3, Q1 and Q4, Q2 and Q3, and Q2 and Q4; a statistically relevant difference has been also found in the distribution of frequencies between the first and second half of the year. On the basis of the results of the presented research, the age effect in the studied population of junior male tennis players can be regarded as significant. CONCLUSIONS: The results of the analysis of the research data confirm the conclusions of similar studies in other sports and prove that in the population of elite junior players

  15. Effects of inundation frequency on microbial N cycling in the riparian zones of pristine watersheds

    Science.gov (United States)

    Malone, E. T.; Bartlett, R.; Pinay, G.; Milner, A. M.

    2012-12-01

    Although the N cycle has been intensively studied new reaction pathways are being discovered. Perturbation by anthropogenic N inputs changes the type of loading and cycling processes in soil systems. Few pristine environments remain in which to study natural controls on the development of N cycling to increase our understanding of the natural development of such mechanisms and with which to compare the effects of anthropogenic inputs. This study took place in Glacier Bay National Park and Preserve, in southeast Alaska (GBNP).Where rapid de-glaciation over the last 250 years has created watersheds of different ages free from anthropogenic N inputs, permitting a unique opportunity to study the evolution of microbial N cycling in pristine soil systems. Soil N cycling was assessed within six study streams selected across a chronosequence of 200 years of primary succession. A combination of field and laboratory methods were used to assess the soil inorganic N status of each study site and assess the net, gross and potential microbial processing of N (ammonification, nitrification and denitrification) present within the soil. Soil samples were collected from the riparian zones of the six river catchments with varying inundation frequencies; namely 1) frequently inundated bare sediment adjacent to the river channel; 2) vegetated floodplain areas further from the channel inundated during high flow events; 3) non flooded. This approach allowed a cross stream comparison of microbial N processing for a range of soil ages, and under differing inundation regimes. Evolution of soil N processing could then be examined, in relation to successional changes in the wider river catchment. One of the key findings was that one of the primary influences on nitrogen cycling processes in the study areas was vegetation cover, as a function of site resilience and distance from stream channel. With distance from a stream channel, a site becomes less dynamic, thereby allowing for the

  16. Effects of thermal cycling on microstructure and properties in Nitinol

    Energy Technology Data Exchange (ETDEWEB)

    Pelton, A.R., E-mail: alan.pelton@nitinol.com [Nitinol Devices and Components, Inc. 47533 Westinghouse Dr., Fremont, CA 94539 (United States); Huang, G.H. [HuaZhong University of Science and Technology, Wuhan, Hubei (China); Moine, P. [Laboratoire d' Etudes des Materiaux en Milieux Agressifs, Universite de La Rochelle, 17042 La Rochelle Cedex 01 (France); Sinclair, R., E-mail: bobsinc@stanford.edu [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Annealed Nitinol was thermally cycled from above A{sub f} to below M{sub f}. Black-Right-Pointing-Pointer We studied the microstructural changes by TEM and transformation behavior by DSC. Black-Right-Pointing-Pointer Increasing cycles decreased the martensite transformation temperatures. Black-Right-Pointing-Pointer There was a concomitant increase in dislocation density. Black-Right-Pointing-Pointer Thermodynamics showed increasing elastic strain energy and irreversible frictional energy. - Abstract: The effects of thermal cycling through the martensite-austenite transformation were investigated in NiTi shape memory alloys with DSC and TEM. Thermal cycling caused a {approx}25 K decrease in M{sub s} with a concomitant increase in dislocation density from {approx}10{sup 12} m{sup -2} to 5 Multiplication-Sign 10{sup 14} m{sup -2} after 100 thermal cycles. Thermodynamic analysis is consistent with increasing elastic strain energy and irreversible frictional energy with cycling. The transformation-induced dislocations were determined to be shear loops with Left-Pointing-Angle-Bracket 0 1 0 Right-Pointing-Angle-Bracket {sub A}{l_brace}1 0 1{r_brace}{sub A} slip system, corresponding to the twinning direction and plane in martensite. It is speculated that the loops form during the movement of the martensite interface and that repeated interfacial movement tends to create bands that consist of highly tangled sessile dislocations. These dislocation bands form along (0.756{sup Macron },0.383{sup Macron },0.192){sub A}, which is 2.3 Degree-Sign from the accepted (0.889{sup Macron },0.404{sup Macron },0.215){sub A} lattice invariant plane. Furthermore, plastically deformed austenitic Nitinol exhibits slip on Left-Pointing-Angle-Bracket 0 1 0 Right-Pointing-Angle-Bracket {sub A}{l_brace}1 0 1{r_brace}{sub A} slip system and forms {l_brace}1 1 0{r_brace} shear bands with several variants of the dislocations within a given region.

  17. Palladium alpha-lipoic acid complex formulation enhances activities of Krebs cycle dehydrogenases and respiratory complexes I-IV in the heart of aged rats.

    Science.gov (United States)

    Sudheesh, N P; Ajith, T A; Janardhanan, K K; Krishnan, C V

    2009-08-01

    Age-related decline in the capacity to withstand stress, such as ischemia and reperfusion, results in congestive heart failure. Though the mechanisms underlying cardiac decay are not clear, age dependent somatic damages to mitochondrial DNA (mtDNA), loss of mitochondrial function, and a resultant increase in oxidative stress in heart muscle cells may be responsible for the increased risk for cardiovascular diseases. The effect of a safe nutritional supplement, POLY-MVA, containing the active ingredient palladium alpha-lipoic acid complex, was evaluated on the activities of the Krebs cycle enzymes such as isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase as well as mitochondrial complexes I, II, III, and IV in heart mitochondria of aged male albino rats of Wistar strain. Administration of 0.05 ml/kg of POLY-MVA (which is equivalent to 0.38 mg complexed alpha-lipoic acid/kg, p.o), once daily for 30 days, was significantly (pKrebs cycle dehydrogenases, and mitochondrial electron transport chain complexes. The unique electronic and redox properties of palladium alpha-lipoic acid complex appear to be a key to this physiological effectiveness. The results strongly suggest that this formulation might be effective to protect the aging associated risk of cardiovascular and neurodegenerative diseases.

  18. [Effect of menstrual cycle on cardiorespiratory system during incremental exercise].

    Science.gov (United States)

    Mesaki, N; Sasaki, J; Shoji, M; Iwasaki, H; Asano, K; Eda, M

    1986-01-01

    According to the results of questionnaires to college athletes, they believe the follicular phase is better than luteal phase for competitive sports. However, it is not clear whether there is significant difference in athletic performance between the two phases of the menstrual cycle. The effects of the menstrual cycle on the cardiorespiratory system were investigated in exercising women who are top players of basketball in Japan. They performed incremental exercise on a cycle ergometer. During the exercise, the ECG and heart rate (HR) were monitored. The expired air was sampled continuously and expiratory gas volume/minute (VE), oxygen uptake (VO2), carbon dioxide output (VCO2), gas exchange ratio(R) and respiratory rate (Resp. E.) were measured. Blood samples were collected to measure the blood lactic acid concentration during the exercise. HR in the luteal phase is higher than in the follicular phase at rest and throughout the exercise. VE, R and Resp. R. at rest and during exercise indicated a tendency to a higher level in the follicular phase. The blood lactic acid concentration during exercise in the follicular phase indicated a tendency to increase more rapidly than in luteal phase. However, no statistical differences in the cardiorespiratory system were detected when the follicular and luteal phase were compared. These results did not indicate conclusively in which phase it is better for athletic women to take part in competitive sports.

  19. Effect of betaine supplementation on cycling sprint performance

    Directory of Open Access Journals (Sweden)

    Pryor J Luke

    2012-04-01

    Full Text Available Abstract Purpose To examine the effect of betaine supplementation on cycling sprint performance. Methods Sixteen recreationally active subjects (7 females and 9 males completed three sprint tests, each consisting of four 12 sec efforts against a resistance equal to 5.5% of body weight; efforts were separated by 2.5 min of cycling at zero resistance. Test one established baseline; test two and three were preceded by seven days of daily consumption of 591 ml of a carbohydrate-electrolyte beverage as a placebo or a carbohydrate-electrolyte beverage containing 0.42% betaine (approximately 2.5 grams of betaine a day; half the beverage was consumed in the morning and the other half in the afternoon. We used a double blind random order cross-over design; there was a 3 wk washout between trials two and three. Average and maximum peak and mean power were analyzed with one-way repeated measures ANOVA and, where indicated, a Student Newman-Keuls. Results Compared to baseline, betaine ingestion increased average peak power (6.4%; p Conclusions One week of betaine ingestion improved cycling sprint power in recreationally active males and females.

  20. Age effects in mortality risk valuation.

    Science.gov (United States)

    Brey, Raul; Pinto-Prades, Jose Luis

    2017-09-01

    We provide more evidence on the functional relationship between willingness-to-pay for risk reductions and age (the senior discount). We overcome many of the limitations of previous literature that has dealt with this issue, namely, the influence of the assumptions used in statistical models on the final results. Given our large sample size (n = 6024) we can use models that are very demanding on data. We use parametric (linear, quadratic, dummies), semi-nonparametric, and non-parametric models. We also compare the marginal and the total approach and show that they provide similar results. We also overcome one of the limitations of the total approach, that is, we include the effects of socioeconomic characteristics that are correlated with age (education and income). Our main result is that all these different approaches produce very similar results, namely, they show an inverted-U relation between the value of a statistical life (VSL) and age. Those results can hardly be attributed to problems of collinearity, omitted variables or statistical assumptions. We find a clear senior discount effect. This effect seems concentrated on those who have lower education and income levels. We also find that the value of a statistical life year (VSLY) increases with age.

  1. Effects of ultraviolet irradiation on the cell cycle.

    Science.gov (United States)

    Bolognia, J L; Sodi, S A; Chakraborty, A K; Fargnoli, M C; Pawelek, J M

    1994-10-01

    Cultured mouse Cloudman melanoma cells, EMT6 breast carcinoma cells, and 3T3 fibroblasts all accumulated in the G2/M phase of the cell cycle when exposed to UVB radiation. The effects of UVB were maximal at 20-30 mJ/cm2 for all three cell lines, and could be observed by flow cytometry as early as 12 hr post irradiation. It has been known since the mid-1970s that MSH receptor binding activity is highest on Cloudman melanoma cells when they are in the G2/M phase of their cycle. Here we show that either UVB irradiation or synchronization of Cloudman cells with colchicine results in a stimulation of MSH binding within 24 hr following treatment, a time when both treatments have resulted in accumulation of cells in the G2/M phase of the cycle. Furthermore, the two treatments performed together on the melanoma cells stimulated MSH receptor activity to the same extent as either treatment performed separately, suggesting that each may be influencing MSH receptor activity solely through a G2/M accumulation of cells. Together, these results raise the possibility that an increase in the number of cells in the G2 phase of the cell cycle is a generalized cellular response to injury, such as UV irradiation. However, in the case of pigment cells this response includes a mechanism for increasing melanin formation, i.e., increased MSH receptor activity. Should this be the case, similar G2/M "injury responses" of other cell types might be expected, consistent with their differentiated phenotypes.

  2. The Effect of Spaceflight on Cartilage Cell Cycle and Differentiation

    Science.gov (United States)

    Doty, Stephen B.; Stiner, Dalina; Telford, William G.

    2000-01-01

    In vivo studies have shown that spaceflight results in loss of bone and muscle. In an effort to understand the mechanisms of these changes, cell cultures of cartilage, bone and muscle have been subjected to spaceflight to study the microgravity effects on differentiated cells. However it now seems possible that the cell differentiation process itself may be the event(s) most affected by spaceflight. For example, osteoblast-like cells have been shown to have reduced cellular activity in microgravity due to an underdifferentiated state (Carmeliet, et al, 1997). And reduced human lymphocyte growth in spaceflight was related to increased apoptosis (Lewis, et al, 1998). Which brings us to the question of whether reduced cellular activity in space is due to an effect on the differentiated cell, an effect on the cell cycle and cell proliferation, or an effect on cell death. This question has not been specifically addressed on previous flights and was the question behind die present study.

  3. Electrochemical aging effects in photovoltaic modules

    Science.gov (United States)

    Mon, G. R.

    Leakage currents were experimentally measured in PV modules undergoing natural aging outdoors, and in PV modules undergoing accelerated aging in laboratory environmental chambers. The significant contributors to module leakage current were identified with a long range goal to develop techniques to reduce or stop module leakage currents. For outdoor aging in general, module leakage current is relatively insensitive to temperature fluctuations, but is very sensitive to moisture effects such as dew, precipitation, and fluctuations in relative humidity. Comparing ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB), module leakage currents are much higher in PVB as compared to EVA for all environmental conditions investigated. Leakage currents proceed in series along two paths, bulk conduction followed by interfacial (surfaces) conduction.

  4. Effect of cholecystokinin on experimental neuronal aging

    Institute of Scientific and Technical Information of China (English)

    Xiao-Jiang Sun; Qin-Chi Lu; Yan Cai

    2005-01-01

    AIM: To observe the effect of cholecystokinin (CCK) on lipofusin value, neuronal dendrite and spine ultrastructure, and total cellular protein during the process of experimental neuronal aging.METHODS: Experimental neuronal aging study model was established by NBA2cellular serum-free culture method. By using single irtracellular lipofusin value from microspectrophotometry,morphology of neuronal dendrites and spines from the scanner electron microscopy, and total cellular protein as the indexes of experimental neuronal aging, we observed the effect of CCK8 on the process of experimental neuronal aging.RESULTS: Under the condition of serum-free culture,intracellular fluorescence value (%) increased with the extension of culture time (1 d 8.51±3.43; 5 d 10.12±3.03;10 d 20.54±10.3; 15 d 36.88±10.49; bP<0.01). When CCK was added to serum-free culture medium, intracellular lipofusin value (%) decreased remarkably after consecutive CCK reaction for 10 and 15 d (control 36.88±10.49; 5 d 32.03±10.01; 10 d 14.37±5.55; 15 d 17.31±4.80; bP<0.01).As the time of serum-free culturing was prolonged, the number of neuronal dendrite and spine cells decreased.The later increased in number when CCK8 was added. CCK8 could improve the total cellular protein in the process of experimental neuronal aging.CONCLUSION: CCK8 may prolong the process of experimental neuronal aging by maintaining the structure and the number of neuronal dendrite and spine cells and changing the total cellular protein.

  5. Lysosomal proteolysis: effects of aging and insulin.

    Science.gov (United States)

    Gromakova, I A; Konovalenko, O A

    2003-07-01

    Age-related characteristics of the effect of insulin on the activity of lysosomal proteolytic enzymes were studied. The relationship between the insulin effect on protein degradation and insulin degradation was analyzed. The effect of insulin on the activities of lysosomal enzymes was opposite in young and old rats (inhibitory in 3-month-old and stimulatory in 24-month-old animals). The activities of proteolytic enzymes were regulated by insulin in a glucose-independent manner: similar hypoglycemic effects of insulin in animals of different ages were accompanied by opposite changes in the activities of lysosomal enzymes. The inhibition of lysosomal enzymes by insulin in 3-month-old rats is consistent with a notion on the inhibitory effect of insulin on protein degradation. An opposite insulin effect in 24-month-old rats (i.e., stimulation of proteolytic activity by insulin) may be partly associated with attenuation of the degradation of insulin, resulting in disturbances in signaling that mediates the regulatory effects of insulin on protein degradation.

  6. On ageing effects in analogue integrated circuits

    OpenAIRE

    Salfelder, Felix (Dipl. Math.)

    2016-01-01

    The behaviour of electronic circuits is influenced by ageing effects. Modelling the behaviour of circuits is a standard approach for the design of faster, smaller, more reliable and more robust systems. In this thesis, we propose a formalization of robustness that is derived from a failure model, which is based purely on the behavioural specification of a system. For a given specification, simulation can reveal if a system does not comply with a specification, and thus provide a failure model...

  7. Impact of female age and male infertility on ovarian reserve markers to predict outcome of assisted reproduction technology cycles

    Directory of Open Access Journals (Sweden)

    Hsieh Kung-Chen

    2009-09-01

    Full Text Available Abstract Background This study was designed to assess the capability of ovarian reserve markers, including baseline FSH levels, baseline anti-Müllerian hormone (AMH levels, and antral follicle count (AFC, as predictors of live births during IVF cycles, especially for infertile couples with advanced maternal age and/or male factors. Methods A prospective cohort of 336 first IVF/ICSI cycles undergoing a long protocol with GnRH agonist was investigated. Patients with endocrine disorders or unilateral ovaries were excluded. Results Among the ovarian reserve tests, AMH and age had a greater area under the receiving operating characteristic curve than FSH in predicting live births. Furthermore, AMH and age were the sole predictive factors of live births for women greater than or equal to 35 years of age; while AMH was the major determinant of live births for infertile couples with absence of male factors by multivariate logistic regression analysis. However, all the studied ovarain reserve tests were not preditive of live births for women Conclusion The serum AMH levels were prognostic for pregnancy outcome for infertile couples with advanced female age or absence of male factors. The predictive capability of ovarian reserve tests is clearly influenced by the etiology of infertility.

  8. Age effects on mediolateral balance control.

    Directory of Open Access Journals (Sweden)

    L Eduardo Cofré Lizama

    Full Text Available BACKGROUND: Age-related balance impairments, particularly in mediolateral direction (ML may cause falls. Sufficiently sensitive and reliable ML balance tests are, however, lacking. This study is aimed to determine (1 the effect of age on and (2 the reliability of ML balance performance using Center of Mass (CoM tracking. METHODS: Balance performance of 19 young (26±3 years and 19 older (72±5 years adults on ML-CoM tracking tasks was compared. Subjects tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Phase-shift (response delay and gain (amplitude difference between the CoM and target in the frequency domain were used to quantify performance. Thirteen older and all young adults were reassessed to determine reliability of balance performance measures. In addition, all older adults performed a series of clinical balance tests and conventional posturography was done in a sub-sample. RESULTS: Phase-shift and gain dropped below pre-determined thresholds (-90 degrees and 0.5 at lower frequencies in the older adults and were even lower below these frequencies than in young adults. Performance measures showed good to excellent reliability in both groups. All clinical scores were close to the maximum and no age effect was found using posturography. ML balance performance measures exhibited small but systematic between-session differences indicative of learning. CONCLUSIONS: The ability to accurately perform ML-CoM tracking deteriorates with age. ML-CoM tracking tasks form a reliable tool to assess ML balance in young and older adults and are more sensitive to age-related impairment than posturography and clinical tests.

  9. Effect of multi-temperature aging on the characterization of aluminum based castings heat treated using fluidized bed technique

    Science.gov (United States)

    Ragab, Kh. A.; Samuel, A. M.; Al-Ahmari, A. M. A.; Samuel, F. H.; Doty, H. W.

    2013-07-01

    The current study investigates the influences of the fluidized bed heat treatment on the quality indices and microstructural characterization of A356.2 and B319.2 castings. Traditional heat treatment technology, employing circulating air convection furnaces (CF), was used to establish a relevant comparison with fluidized sand bed (FB) for the heat treatment of the alloys investigated, employing T6 continuous aging cycles or multi-temperature aging cycles. The results of alloys subjected to multi-temperature aging cycles reveal that the strength results obtained after the T6 continuous aging treatment of A356 alloys are not improved by means of multi-temperature aging cycles, indicating therefore that the optimum properties are obtained using a T6 aging treatment. The optimum strength properties of B319.2 alloys, however, is obtained by applying multi-temperature aging cycles such as, for example, 230 °C/2 h followed by 180 °C/8 h, rather than T6 aging treatment. In the case of multi-temperature aging cycles, the modification factor has the most significant role in improving the quality index values of 356 and 319 alloys. The FB heattreated alloys have the highest strength values for all heat treatment cycles compared to CF heat-treated alloys; however, the FB has no significant effect on the quality values of 319 alloys compared to the CF.

  10. Learning at Every Age? Life Cycle Dynamics of Adult Education in Europe

    Science.gov (United States)

    Beblavy, Miroslav; Thum, Anna-Elisabeth; Potjagailo, Galina

    2014-01-01

    Adult learning is seen as a key factor for enhancing employment, innovation and growth. The aim of this paper is to understand the points in the life cycle at which adult learning takes place and whether it leads to reaching a medium or high level of educational attainment. We perform a synthetic panel analysis of adult learning for cohorts aged…

  11. Water cycles in closed ecological systems: effects of atmospheric pressure

    Science.gov (United States)

    Rygalov, Vadim Y.; Fowler, Philip A.; Metz, Joannah M.; Wheeler, Raymond M.; Bucklin, Ray A.; Sager, J. C. (Principal Investigator)

    2002-01-01

    In bioregenerative life support systems that use plants to generate food and oxygen, the largest mass flux between the plants and their surrounding environment will be water. This water cycle is a consequence of the continuous change of state (evaporation-condensation) from liquid to gas through the process of transpiration and the need to transfer heat (cool) and dehumidify the plant growth chamber. Evapotranspiration rates for full plant canopies can range from 1 to 10 L m-2 d-1 (1 to 10 mm m-2 d-1), with the rates depending primarily on the vapor pressure deficit (VPD) between the leaves and the air inside the plant growth chamber. VPD in turn is dependent on the air temperature, leaf temperature, and current value of relative humidity (RH). Concepts for developing closed plant growth systems, such as greenhouses for Mars, have been discussed for many years and the feasibility of such systems will depend on the overall system costs and reliability. One approach for reducing system costs would be to reduce the operating pressure within the greenhouse to reduce structural mass and gas leakage. But managing plant growth environments at low pressures (e.g., controlling humidity and heat exchange) may be difficult, and the effects of low-pressure environments on plant growth and system water cycling need further study. We present experimental evidence to show that water saturation pressures in air under isothermal conditions are only slightly affected by total pressure, but the overall water flux from evaporating surfaces can increase as pressure decreases. Mathematical models describing these observations are presented, along with discussion of the importance for considering "water cycles" in closed bioregenerative life support systems.

  12. Effect of isokinetic cycling versus weight training on maximal power output and endurance performance in cycling.

    Science.gov (United States)

    Koninckx, Erwin; Van Leemputte, Marc; Hespel, Peter

    2010-07-01

    The aim of this study was to compare the effects of a weight training program for the leg extensors with isokinetic cycling training (80 rpm) on maximal power output and endurance performance. Both strength training interventions were incorporated twice a week in a similar endurance training program of 12 weeks. Eighteen trained male cyclists (VO(2peak) 60 +/- 1 ml kg(-1) min(-1)) were grouped into the weight training (WT n = 9) or the isokinetic training group (IT n = 9) matched for training background and sprint power (P (max)), assessed from five maximal sprints (5 s) on an isokinetic bicycle ergometer at cadences between 40 and 120 rpm. Crank torque was measured (1 kHz) to determine the torque distribution during pedaling. Endurance performance was evaluated by measuring power, heart rate and lactate during a graded exercise test to exhaustion and a 30-min performance test. All tests were performed on subjects' individual race bicycle. Knee extension torque was evaluated isometrically at 115 degrees knee angle and dynamically at 200 degrees s(-1) using an isokinetic dynamometer. P (max) at 40 rpm increased in both the groups (~15%; P < 0.05). At 120 rpm, no improvement of P (max) was found in the IT training group, which was possibly related to an observed change in crank torque at high cadences (P < 0.05). Both groups improved their power output in the 30-min performance test (P < 0.05). Isometric knee extension torque increased only in WT (P < 0.05). In conclusion, at low cadences, P (max) improved in both training groups. However, in the IT training group, a disturbed pedaling technique compromises an improvement of P (max) at high cadences.

  13. Effects of dry aging of bone-in and boneless strip loins using two aging processes for two aging times.

    Science.gov (United States)

    Degeer, S L; Hunt, M C; Bratcher, C L; Crozier-Dodson, B A; Johnson, D E; Stika, J F

    2009-12-01

    This experiment investigated the combined effects of two dry-aging methods (unpackaged and in a bag), two loin-cut styles (bone-in shell loins and boneless strip loins), and two aging times (21 and 28days) on the physical, chemical, sensory, and microbial properties of dry-aged beef. Sections from shell and strip loin were assigned randomly to be aged unpackaged or aged packaged in a bag with high moisture permeability. Weight losses increased with aging time. Shell loins lost more (Pdry aging in a bag had less (P0.05) in any of the sensory traits between shell and strip loins or dry aging using a traditional method or in a bag. Dry aging in a bag creates positive effects on yields, no negative effects on product quality, and adds flexibility and control of the aging environment.

  14. Effects of Wearing a Helmet on Thermal Balance While Cycling in the Heat.

    Science.gov (United States)

    Gisolfi, C V; Rohlf, D P; Navarude, S N; Hayes, C L; Sayeed, S A

    1988-01-01

    In brief: Many cyclists refuse to wear helmets because they produce discomfort and drag. To determine the effects of wearing a helmet on thermal balance and rating of perceived exertion while cycling in the heat, six male competitive cyclists aged 19 to 32 rode a stationary bicycle attached to a road-racing simulator in an environmentally controlled chamber for two hours at 70% V O2 max. Measurements were taken of rectal and skin temperatures, V O2, heart rate, sweat rate, and rating of perceived exertion. The results showed that (under the experimental conditions used) wearing a helmet while cycling in the heat does not alter thermal balance or cardiovascular strain compared with not wearing a helmet.

  15. Effect of Feeding-Fasting Cycles on Oxygen Consumption and Bioenergetics of Yellow Perch

    Science.gov (United States)

    Chipps, Steven R.; Travis W. Schaeffer,; Daniel E. Spengler,; Casey W. Schoenebeck,; Michael L. Brown,

    2012-01-01

    We measured growth and oxygen consumption of age-1 yellow perch Perca flavescenssubjected to ad libitum (control) or variable feeding cycles of 2 (i.e., 2 d of feed, 2 d of deprivation), 6, or 12 d for a 72-d period. Individual, female yellow perch (initial weight = 51.9 ± 0.9 g [mean ± SE]) were stocked in 110-L aquaria to provide six replicates per treatment and fed measured rations of live fathead minnow Pimephales promelas. Consumption, absolute growth rate, growth efficiency, and oxygen consumption were similar among feeding regimens. However, growth trajectories for fish on the 2-d cycle were significantly lower than other feed–fast cycles. Hyperphagia occurred in all treatments. Bioenergetics model simulations indicated that consumption was significantly underestimated (t = 5.4, df = 4, P = 0.006), while growth was overestimated (t = −5.5, df = 4, P = 0.005) for fish on the 12-d cycle. However, model errors detected between observed and predicted values were low, ranging from −10.1% to +7.8%. We found that juvenile yellow perch exhibited compensatory growth (CG), but none of the feed–fast treatments resulted in growth overcompensation. Likewise, we found no evidence that respiration rates varied with CG, implying that yellow perch bioenergetics models could be used to predict the effects of feeding history and CG response on food consumption and fish growth.

  16. Methylation at global LINE-1 repeats in human blood are affected by gender but not by age or natural hormone cycles.

    Directory of Open Access Journals (Sweden)

    Osman El-Maarri

    Full Text Available Previously, we reported on inter-individual and gender specific variations of LINE-1 methylation in healthy individuals. In this study, we investigated whether this variability could be influenced by age or sex hormones in humans. To this end, we studied LINE-1 methylation in vivo in blood-derived DNA from individuals aged 18 to 64 years and from young healthy females at various hormone levels during the menstrual cycle. Our results show that no significant association with age was observed. However, the previously reported increase of LINE-1 methylation in males was reconfirmed. In females, although no correlation between LINE-1 or Alu methylation and hormone levels was observed, a significant stable individual specific level of methylation was noted. In vitro results largely confirmed these findings, as neither estrogen nor dihydrotestosterone affected LINE-1 or Alu methylation in Hek293T, HUVEC, or MDA-kb2 cell lines. In contrast, a decrease in methylation was observed in estrogen-treated T47-Kbluc cell lines strongly expressing estrogen receptor. The very low expression of estrogen receptor in blood cells could explain the observed insensitivity of methylation at LINE-1 to natural hormonal variations in females. In conclusion, neither natural cycle of hormones nor age has a detectable effect on the LINE-1 methylation in peripheral blood cells, while gender remains an important factor.

  17. Biological properties of differently-aged human keratinocytes:population doubling time growth curve and cell cycle analysis

    Institute of Scientific and Technical Information of China (English)

    Hui-qun Ma; Jie Feng; Lech Chyczewski; Jacek Niklinski

    2009-01-01

    Objective To explore the biological properties of keratinocytes from differently-aged healthy human beings. Methods Keratinocytes from fetus, teenager and middle-aged groups were separated and cultured. The population doubling time (PDT) and cell growth curve in different cells were compared, and the cell cycles were analyzed by flow cytometry. Results ① In primary culture of keratinocytes, the adherence time in middle-aged group was longer than that in fetus and teenager groups. However, all cell morphology showed no obvioas differences. In subculture of kecatinocytes, with donator's age increasing, time of cell adherence prolonged, passage number decreused and differences in cell morphology were obrioas. ② The average PDT of keratinocytes was shorter in fetus group than in teenager and middle-aged groups. Bat difference in cell growth curve between different passages was not observed. ③ Keratinocytes showed G2/M period in fetus group but G0/G1 period in teenager and middle-aged groups mainly. Conclusion As age increases, the biological properties of keratinocytes change obviously.

  18. Environmental noise alters gastric myoelectrical activity: Effect of age

    Institute of Scientific and Technical Information of China (English)

    James S Castle; Jin-Hong Xing; Mark R Warner; Mark A Korsten

    2007-01-01

    AIM: To evaluate the effect of age and acoustic stress on gastric myoelectrical activity (GMA) and autonomic nervous system function,METHODS: Twenty-one male subjects (age range 22-71years, mean 44 years) were recruited and exposed, in random order, to three auditory stimuli (Hospital noise,conversation babble and traffic noise) after a 20-min baseline. All periods lasted 20 min and were interspersed with a 10 min of recovery. GMA was obtained using a Synectics Microdigitrapper. Autonomic nerve function was assessed by monitoring blood pressure and heart rate using an automatic recording device.RESULTS: Dominant power tended to decrease with increase of age (P<0.05). The overall percentage of three cycle per minute (CPM) activity decreased during exposure to hospital noise (12.0%, P < 0.05), traffic noise (13.9%, P < 0.05), and conversation babble(7.1%). The subjects in the younger group (< 50 years)showed a consistent reduction in the percentage of 3CPM activity during hospital noise (22.9%, P < 0.05),traffic noise (19.0%, P < 0.05), and conversation babble(15.5%). These observations were accompanied by a significant increase in bradygastria: hospital noise (P< 0.05) and traffic noise (P < 0.05). In contrast, the subjects over 50 years of age did not exhibit a significant decrease in 3 CPM activity. Regardless of age, noise did not alter blood pressure or heart rate.CONCLUSION: GMA changes with age. Loud noise can alter GMA, especially in younger individuals. Our data indicate that even short-term exposure to noise may alter the contractility of the stomach.

  19. Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

    Directory of Open Access Journals (Sweden)

    Yukiko Nariai

    Full Text Available Periodical cicadas (Magicicada spp. in the USA are divided into three species groups (-decim, -cassini, -decula of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods" with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

  20. Thermal aging effects in refractory metal alloys

    Science.gov (United States)

    Stephens, Joseph R.

    1987-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  1. Moonstruck? The effect of the lunar cycle on seizures.

    Science.gov (United States)

    Baxendale, Sallie; Fisher, Jennifer

    2008-10-01

    Recent reports on the effects of the lunar cycle on seizure occurrence have yielded mixed results. If the moon phase is influential, we hypothesized that this would be due to the moon's contribution to nocturnal illumination, rather than its waxing or waning state, and that significant correlations would not be apparent if local cloud cover were controlled for. We found a significant negative correlation between the mean number of seizures and the fraction of the moon illuminated by the sun (rho=-0.09, P<0.05) in 1571 seizures recorded in a dedicated epilepsy inpatient unit over 341 days. This correlation disappeared when we controlled for the local clarity of the night sky, suggesting that it is the brightness of the night and the contribution the moon phase makes to nocturnal luminance, rather than the moon phase per se, that may influence the occurrence of epileptic seizures.

  2. 10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

    Science.gov (United States)

    2010-01-01

    ...) ENERGY STAR qualified and FEMP designated products may be assumed to be life-cycle cost-effective. (b) In... 10 Energy 3 2010-01-01 2010-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle...

  3. Effect of staurosporine on cycle of human gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Min-Wen Ha; Ke-Zuo Hou; Yun-Peng Liu; Yuan Yuan

    2004-01-01

    AIM: To study the effect of staurosporine (ST) on the cell cycle of human gastriccancer cell lines MGC803 and SGC7901.METHODS: Cell proliferation was evaluated by trypan blue dye exclusion method. Apoptotic morphology was observed under a transmission electron microscope. Changes of cell cycle and apoptotic peaks of cells were determined by flow cytometry. Expression of p21WAFI gene was examined using immunohistochemistry and RT-PCR.RESULTS: The growth of MGC803 and SGC7901 cells was inhibited by ST. The inhibitory concentrations against 50% cells (IC50) at 24 h and 48 h were 54 ng/ml and 23 ng/ml for MlGC803, and 61 ng/ml and 37 ng/ml for SGC7901. Typical apoptotic bodies and apoptotic peaks were observed 24 hafter cells were treated wth ST at a concentration of 200ng/ml. The percentage of cells at G0/G1 phase was decreased and that of cells at G2/M was increased significantly in the group treated wth ST at the concentrations of 40ng/ml,60 ng/ml, 100 ng/ml for 24 h, compared with the control group (P<0.01). The expression levels of p21WAFI gene in both MGC803 and SGC7901 cells were markedly up-regulated after treatment with ST.CONCLUSION: ST can cause arrest of gastric cancer cells at G2/M phase, which may be one of the mechanisms that inhibit cell proliferation and cause apoptosis in these cells.Effect of ST on cells at G2/M phase may be attributed to the up-regulattion of p21WAFI gene.

  4. Non-Destructive Analysis of Degradation Mechanisms in Cycle-Aged Graphite/LiCoO2 Batteries

    Directory of Open Access Journals (Sweden)

    Liqiang Zhang

    2014-09-01

    Full Text Available Non-destructive analysis of degradation mechanisms can be very beneficial for the prognostics and health management (PHM study of lithium-ion batteries. In this paper, a type of graphite/LiCoO2 battery was cycle aged at high ambient temperature, then 25 parameters of the multi-physics model were identified. Nine key parameters degraded with the cycle life, and they were treated as indicators of battery degradation. Accordingly, the degradation mechanism was discussed by using the multi-physics model and key parameters, and the reasons for capacity fade and the internal resistance increase were analyzed in detail. All evidence indicates that the formation reaction of the solid electrolyte interface (SEI film is the main cause of battery degradation at high ambient temperature.

  5. Desiccant aging and its effect on desiccant cooling system performance

    Energy Technology Data Exchange (ETDEWEB)

    Belding, W.A. [Innovative Research Enterprises, Danville, CA (United States); Delmas, M.P.F.; Holeman, W.D. [LaRoche Industries Inc., Baton Rouge, LA (United States)

    1996-05-01

    Desiccants used for the purpose of space conditioning or enthalpy transfer can be subjected to hundreds of thousands of adsorption/regeneration cycles over their useful life. Studying the loss of a desiccant`s equilibrium water adsorption capacity after exposure to thermal cycling is a common method for quantifying desiccant aging. Since isotherm shape and desiccant capacity can be related to overall cooling-system performance, system cooling capacity and coefficients of performance over time can be predicted. Adsorption isotherms for several different desiccants have been determined after subjecting the materials to varying numbers of thermal cycles in a specially designed test unit capable of adsorption/desorption cycling every 10 min. Aging curves for a new Type 1M desiccant developed specifically for desiccant cooling applications by LaRoche Industries Inc. are compared to other commonly used desiccants. (author)

  6. Speciation Effect in the Penna Aging Model

    Science.gov (United States)

    Łaszkiewicz, A.; Szymczak, Sz.; Cebrat, S.

    We have simulated the evolution of diploid, sexually reproducing populations using the Penna model of aging. We have noted that diminishing the recombination frequency during the gamete production generates a specific diversity of genomes in the populations. When two populations independently evolving for some time were mixed in one environmental niche of the limited size and crossbreeding between them was allowed, the average lifespan of hybrids was significantly shorter than the lifespan of the individuals of parental lines. Another effect of higher hybrid mortality is the faster elimination of one parental line from the shared environment. The two populations living in one environment co-exist much longer if they are genetically separated — they compete as two species instead of crossbreeding. This effect can be considered as the first step to speciation — any barrier eliminating crossbreeding between these populations, leading to speciation, would favor the populations.

  7. Posture and the circulation: the age effect.

    Science.gov (United States)

    Smith, J J; Porth, C J

    1991-01-01

    The primary instigator of circulatory response to the upright posture is the rapid displacement of about 10% of blood volume from the thorax to the lower body. The resultant hemodynamic deficit induces postural intolerance, especially orthostatic hypotension, in elderly over 70 years of age and in some young subjects after exposure to weightlessness. In this review, our objectives have been: 1) to describe in the normal subject the hemodynamic consequences of the headup posture, as well as lower body negative pressure, the compensatory responses intended to cope with these stresses, and their mechanisms; 2) to outline the effect of age on the circulatory responses to these stresses; and (3) to analyze and compare the tests currently used to assess circulatory tolerance. Our ability to design effective countermeasures to orthostatic circulatory intolerance is severely handicapped by our inadequate knowledge of the basic hemodynamic events incident to normal and abnormal orthostatic tolerance. We believe that better understanding and standardization of the postural tests, better experimental design to include greater emphasis on inter and intra-individual variability, and wider application of currently available noninvasive circulatory techniques would greatly improve the prospects for success in this research area.

  8. Sociological effects on vocal aging: Age related F0 effects in two languages

    Science.gov (United States)

    Nagao, Kyoko

    2005-04-01

    Listeners can estimate the age of a speaker fairly accurately from their speech (Ptacek and Sander, 1966). It is generally considered that this perception is based on physiologically determined aspects of the speech. However, the degree to which it is due to conventional sociolinguistic aspects of speech is unknown. The current study examines the degree to which fundamental frequency (F0) changes due to advanced aging across two language groups of speakers. It also examines the degree to which the speakers associate these changes with aging in a voice disguising task. Thirty native speakers each of English and Japanese, taken from three age groups, read a target phrase embedded in a carrier sentence in their native language. Each speaker also read the sentence pretending to be 20-years younger or 20-years older than their own age. Preliminary analysis of eighteen Japanese speakers indicates that the mean and maximum F0 values increase when the speakers pretended to be younger than when they pretended to be older. Some previous studies on age perception, however, suggested that F0 has minor effects on listeners' age estimation. The acoustic results will also be discussed in conjunction with the results of the listeners' age estimation of the speakers.

  9. Effects of thermal cycling on magnetic properties of lunar analogs

    Science.gov (United States)

    Barron, A. M.; Shive, P. N.

    1984-01-01

    An experimental study has been performed to determine whether stresses associated with thermal cycling cracks can affect the coercivity of remanence carried by iron in lunar samples. Initially, samples were cycled up to 100 times in a refrigerator over a period of about 30 min per cycle. In a second set of experiments, samples were dipped directly into liquid nitrogen up to 100 times at about 1 min per cycle. Comparison of AF demagnetization curves of weak field anhysteretic remanent magnetization before and after cycling revealed no systematic differences. Calculations based on a model of spherical iron grains within olivine or troilite indicate that it is unlikely that the iron will crack under thermal stress. Thus, thermal cycling does not appear to provide an explanation for increasing the stability of remanence in samples from the lunar surface.

  10. A Prospective Randomized Controlled Study of Laser-Assisted Hatching on the Outcome of First Fresh IVF-ET Cycle in Advanced Age Women.

    Science.gov (United States)

    Shi, Wenhao; Hongwei, Tan; Zhang, Wei; Li, Na; Li, Mingzhao; Li, Wei; Shi, Juanzi

    2016-10-01

    There is no sufficient data to conclude the benefit of assisted hatching (AH) for advanced age patients. However, AH is routinely performed for advanced age patients undergoing in vitro fertilization (IVF) in China based on some retrospective evidence. It is important to assess the benefit of AH procedure for advanced age patients, especially by analyzing the data from China. This is a prospective randomized controlled trial to evaluate the effect of laser AH in the advanced age patients undergoing IVF. A total of 256 patients conformed to the inclusion criteria, and 78 were excluded by exclusion criteria. A total of 178 patients were eligible and randomized to 2 groups (82 AH group and 96 control group). Laser AH (zona thinning) was performed in the AH group. There were no statistical significance in basic clinical parameters between the 2 groups. No difference was found in implantation rate (AH vs control, 32.45% vs 39.29%) and clinical pregnancy rate (AH vs control, 48.78% vs 59.38%). Our data did not find any benefit of laser AH in improving implantation or pregnancy rates in advanced age women. Due to the potential risk and increasing financial burden, AH should not be routinely performed in first fresh IVF embryo transfer cycle for advanced age women.

  11. Effect of pulse duty cycle on Inconel 718 laser welds

    Science.gov (United States)

    McCay, M. H.; McCay, T. D.; Dahotre, N. B.; Sharp, C. M.; Sedghinasab, A.; Gopinathan, S.

    1989-01-01

    Crack sensitive Inconel 718 was laser pulse welded using a 3.0 kW CO2 laser. Weld shape, structure, and porosity were recorded as a function of the pulse duty cycle. Within the matrix studied, the welds were found to be optimized at a high (17 ms on, 7 ms off) duty cycle. These welds were superior in appearance and lack of porosity to both low duty cycle and CW welds.

  12. Effect of the Rotor Crank System on Cycling Performance

    Science.gov (United States)

    Jobson, Simon A.; Hopker, James; Galbraith, Andrew; Coleman, Damian A.; Nevill, Alan M.

    2009-01-01

    The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min-1) completed 6-weeks of their normal training using either a conventional (CON) or the novel Rotor (ROT) pedal system. All participants then completed two 40.23-km time-trials on an air-braked ergometer, one using CON and one using ROT. Mean performance speeds were not different between trials (CON = 41.7 km·h-1 vs. ROT = 41.6 km·h-1, P > 0.05). Indeed, the pedal system used during the time-trials had no impact on any of the measured variables (power output, cadence, heart rate, VO2, RER, gross efficiency). Furthermore, the ANOVA identified no significant interaction effect between main effects (Time-trial crank system*Training crank system, P > 0.05). To the authors’ knowledge, this is the first study to examine the effects of the Rotor system on endurance performance rather than endurance capacity. These results suggest that the Rotor system has no measurable impact on time-trial performance. However, further studies should examine the importance of the Rotor ‘regulation point’ and the suggestion that the Rotor system has acute ergogenic effects if used infrequently. Key points The Rotor crank system does not improve gross efficiency in well-trained cyclists. The Rotor crank system has no measurable impact on laboratory 40.23-km time-trial performance. A 6-week period of familiarisation does not increase the effectiveness of the Rotor crank system. PMID:24150012

  13. Aging effects on molybdate lability in soils.

    Science.gov (United States)

    Kirby, Jason K; McLaughlin, Michael J; Ma, Yibing; Ajiboye, Babasola

    2012-10-01

    Aging reactions in soils can influence the lability and hence bioavailability of added metals in soils through their removal from labile pools into pools from which desorption is slow (non-labile pools). The aims of this study were to examine the effect of aging reactions on the lability of soluble molybdate (MoO(4)(2-)) added into soils with varying physical and chemical properties and develop models to predict changes in the labile pool of MoO(4)(2-) in soils with incubation time. Soils were spiked with soluble MoO(4)(2-) at quantities sufficient to inhibit barley root growth by 10% (EC(10)) or 90% (EC(90)) and incubated for up to 18 months. The labile pool of MoO(4)(2-) (E value) was observed to decrease in soils with incubation time, particularly in soils with high clay content. A strong relationship was observed between measures of MoO(4)(2-) lability in soils determined using E and L value techniques (R(2)=0.98) suggesting E values provided a good measure of the potential plant available pool of MoO(4)(2-) in soils. A regression model was developed that indicates clay content and incubation time were the most important factors affecting the labile pool of MoO(4)(2-) in soils with time after addition (R(2)=0.70-0.75). The aging model developed suggests soluble MoO(4)(2-) will be removed into non-labile pools more rapidly with time in neutral to alkaline clay soils than in acidic sandy soils. Labile MoO(4)(2-) concentrations in molybdenum (Mo) contaminated soils was found to be <10% of the total Mo concentrations in soils.

  14. Allergy immunotherapy across the life cycle to promote active and healthy ageing

    DEFF Research Database (Denmark)

    Calderon, M A; Demoly, P; Casale, T

    2016-01-01

    Allergic diseases often occur early in life and persist throughout life. This life-course perspective should be considered in allergen immunotherapy. In particular it is essential to understand whether this al treatment may be used in old age adults. The current paper was developed by a working g...

  15. Allergy immunotherapy across the life cycle to promote active and healthy ageing

    DEFF Research Database (Denmark)

    Calderon, M A; Demoly, P; Casale, T

    2016-01-01

    group of AIRWAYS integrated care pathways for airways diseases, the model of chronic respiratory diseases of the European Innovation Partnership on active and healthy ageing (DG CONNECT and DG Santé). It considered (1) the political background, (2) the rationale for allergen immunotherapy across...

  16. Allergy immunotherapy across the life cycle to promote active and healthy ageing: From research to policies

    NARCIS (Netherlands)

    M. Calderon (Moises); P. Demoly; T.B. Casale (Thomas); C.A. Akdis; C. Bachert (Claus); Bewick, M.; Bilò, B.M.; B. Bohle (B.); S. Bonini (Sergio); A. Bush (Andrew); Caimmi, D.P.; G. Canonica (Gwalter); D. Cardona (Doris); A.M. Chiriac (A.); L. Cox (Linda); A. Custovic; F. de Blay; Devillier, P.; Didier, A.; Di Lorenzo, G.; G. Du Toit (George); S.R. Durham (Stephen); C. Eng (Charis); A. Fiocchi (Alessandro); Fox, A.T.; R.G. van Wijk (Roy Gerth); Gomez, R.M.; Haathela, T.; S. Halken (Susanne); P.W. Hellings (P.); L. Jacobsen; P.M. Just; Tanno, L.K.; J. Kleine-Tebbe (Jörg); L. Klimek (Ludger); E.F. Knol (Edward Frank); P. Kuna; D. Larenas-Linnemann (Désirée); A. Linneberg (Allan); Matricardi, M.; H.-J. Malling; Moesges, R.; Mullol, J.; Muraro, A.; N. Papadopoulos; G. Passalacqua (Giovanni); Pastorello, E.; O. Pfaar (Oliver); D. Price (David); P.R. Del Rio (P. Rodriguez); Ruëff, R.; Samolinski, B.; G.K. Scadding; Senti, G.; Shamji, M.H.; A. Sheikh (Aziz); J.C. Sisul (J.); D. Solé (D.); G.J. Sturm; Tabar, A.; R. Van Ree; Ventura, M.T.; C. Vidal (Carmen); E.M. Varga; M. Worm (M.); T. Zuberbier (Torsten); J. Bousquet (Jean)

    2016-01-01

    textabstractAllergic diseases often occur early in life and persist throughout life. This life-course perspective should be considered in allergen immunotherapy. In particular it is essential to understand whether this al treatment may be used in old age adults. The current paper was developed by a

  17. The Effect of Age-Correction on IQ Scores among School-Aged Children Born Preterm

    Science.gov (United States)

    Roberts, Rachel M.; George, Wing Man; Cole, Carolyn; Marshall, Peter; Ellison, Vanessa; Fabel, Helen

    2013-01-01

    This study examined the effect of age-correction on IQ scores among preterm school-aged children. Data from the Flinders Medical Centre Neonatal Unit Follow-up Program for 81 children aged five years and assessed with the WPPSI-III, and 177 children aged eight years and assessed with the WISC-IV, were analysed. Corrected IQ scores were…

  18. Effects of thermal cycling on aluminum metallization of power diodes

    DEFF Research Database (Denmark)

    Brincker, Mads; Pedersen, Kristian Bonderup; Kristensen, Peter Kjær

    2015-01-01

    Reconstruction of aluminum metallization on top of power electronic chips is a well-known wear out phenomenon under power cycling conditions. However, the origins of reconstruction are still under discussion. In the current study, a method for carrying out passive thermal cycling of power diodes...

  19. Effective Integration of Life Cycle Engineering in Education

    NARCIS (Netherlands)

    Oude Luttikhuis, Ellen; Toxopeus, Marten E.; Lutters, Diederick

    2015-01-01

    In practice, applying life cycle engineering in product design and development requires an integrated approach, because of the many stakeholders and variables (e.g. cost, environmental impact, energy, safety, quality) involved in a complete product life cycle. In educating young engineers, the same

  20. Menstrual cycle effects on attitudes toward romantic kissing.

    Science.gov (United States)

    Wlodarski, Rafael; Dunbar, Robin I M

    2013-12-01

    Hormonal changes associated with the human menstrual cycle have been previously found to affect female mate preference, whereby women in the late follicular phase of their cycle (i.e., at higher risk of conception) prefer males displaying putative signals of underlying genetic fitness. Past research also suggests that romantic kissing is utilized in human mating contexts to assess potential mating partners. The current study examined whether women in their late follicular cycle phase place greater value on kissing at times when it might help serve mate assessment functions. Using an international online questionnaire, results showed that women in the follicular phase of their menstrual cycle felt that kissing was more important at initial stages of a relationship than women in the luteal phase of their cycle. Furthermore, it was found that estimated progesterone levels were a significant negative predictor for these ratings.

  1. EFFECT OF THE ROTOR CRANK SYSTEM ON CYCLING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Simon A. Jobson

    2009-09-01

    Full Text Available The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min-1 completed 6-weeks of their normal training using either a conventional (CON or the novel Rotor (ROT pedal system. All participants then completed two 40.23-km time-trials on an air-braked ergometer, one using CON and one using ROT. Mean performance speeds were not different between trials (CON = 41.7 km·h-1 vs. ROT = 41.6 km·h-1, P > 0.05. Indeed, the pedal system used during the time-trials had no impact on any of the measured variables (power output, cadence, heart rate, VO2, RER, gross efficiency. Furthermore, the ANOVA identified no significant interaction effect between main effects (Time-trial crank system*Training crank system, P > 0.05. To the authors' knowledge, this is the first study to examine the effects of the Rotor system on endurance performance rather than endurance capacity. These results suggest that the Rotor system has no measurable impact on time-trial performance. However, further studies should examine the importance of the Rotor 'regulation point' and the suggestion that the Rotor system has acute ergogenic effects if used infrequently

  2. Mobile phone use while cycling : Incidence and effects on behaviour and safety

    NARCIS (Netherlands)

    De Waard, D.; Schepers, P.; Ormel, W.; Brookhuis, K.A.

    2010-01-01

    The effects of mobile phone use on cycling behaviour were studied. In study 1, the prevalence of mobile phone use while cycling was assessed. In Groningen 2.2% of cyclists were observed talking on their phone and 0.6% were text messaging or entering a phone number. In study 2, accident-involved cycl

  3. Does a frozen embryo transfer ameliorate the effect of elevated progesterone seen in fresh transfer cycles?

    Science.gov (United States)

    Healy, Mae Wu; Patounakis, George; Connell, Matt T; Devine, Kate; DeCherney, Alan H; Levy, Michael J; Hill, Micah J

    2016-01-01

    To compare the effect of progesterone (P) on the day of trigger in fresh assisted reproduction technology (ART) transfer cycles versus its effect on subsequent frozen embryo transfer (FET) cycles. Retrospective cohort study. Large private ART practice. Fresh autologous and FET cycles from 2011-2013. None. Live birth. A paired analysis of patients who underwent both a fresh transfer and subsequent FET cycle and an unpaired analysis of data from all fresh transfer cycles and all FET cycles were performed. We analyzed 1,216 paired and 4,124 unpaired cycles, and P was negatively associated with birth in fresh but not FET cycles in all analyses. Interaction testing of P and cycle type indicated P had a different association with birth in fresh versus FET cycles. When P was ≥ 2 ng/mL at the time of trigger, live birth was more likely in FET versus fresh cycles in the paired analysis (47% vs. 10%), in the unpaired analysis (51% vs. 14%), and in unpaired, good blastocyst only transfer subgroup (51% vs. 29%). Live birth was similar in FET cycles, with P ≥ 2 ng/mL versus P birth was lower in fresh cycles, with P ≥ 2 ng/mL versus P trigger during the initial fresh cycle were negatively associated with live birth in the fresh transfer cycles but not in subsequent FET cycles. Freezing embryos and performing a subsequent FET cycle ameliorates the effect of elevated P on live-birth rates. Published by Elsevier Inc.

  4. The Great Ice Age cycles associated with the variation of the atmospheric heat engine efficiency

    Institute of Scientific and Technical Information of China (English)

    汤懋苍; 郭维栋

    2000-01-01

    Investigating all the Great Ice Age events throughout the Earth’s history, each was found to follow a strong mountain-making process. Therefore, a hypothesis was put forward with its causality chain as: strong mountain-making process→great disparity in topography on the Earth surface→introducing efficient atmospheric circulation system (plateau monsoon)→increase in global atmospheric heat engine efficiency →generating more atmospheric kinetic energy → enhancing the planetary westerly (under the condition that the huge relief is longitudinal on the whole )→widening the temperature difference between the equator and the polar regions (restrained by the thermal wind law)→sharp cooling in high latitudes and the polars (supposing the solar radiation was approximately constant)→forming a Great Ice Age event.

  5. The Great Ice Age cycles associated with the variation of the atmospheric heat engine efficiency

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Investigating all the Great Ice Age events throughout the Earth's history, each was found to follow a strong mountain-making process. Therefore, a hypothesis was put forward with its causality chain as: strong mountain-making process→great disparity in topography on the Earth surface→introducing efficient atmospheric circulation system (plateau monsoon)→increase in global atmospheric heat engine efficiency→generating more atmospheric kinetic energy→enhancing the planetary westerly (under the condition that the huge relief is longitudinal on the whole )→widening the temperature difference between the equator and the polar regions (restrained by the thermal wind law)→sharp cooling in high latitudes and the polars (supposing the solar radiation was approximately constant)→forming a Great Ice Age event.

  6. Relationship between blood pressure and cerebral blood flow during supine cycling: influence of aging

    Science.gov (United States)

    Hoffman, Keegan; Tzeng, Yu-Chieh; Hansen, Alex; Ainslie, Philip N.

    2015-01-01

    The cerebral pressure-flow relationship can be quantified as a high-pass filter, where slow oscillations are buffered (exercise, previous studies have reported paradoxical transfer function analysis (TFA) findings (altered phase or intact gain). This study aimed to determine whether these previous findings accurately represent this relationship. Both younger (20–30 yr; n = 10) and older (62–72 yr; n = 9) adults were examined. To enhance the signal-to-noise ratio, large oscillations in blood pressure (via oscillatory lower body negative pressure; OLBNP) were induced during steady-state moderate intensity supine exercise (∼45–50% of heart rate reserve). Beat-to-beat blood pressure, cerebral blood velocity, and end-tidal Pco2 were monitored. Very low frequency (0.02–0.07 Hz) and low frequency (0.07–0.20 Hz) range spontaneous data were quantified. Driven OLBNP point estimates were sampled at 0.05 and 0.10 Hz. The OLBNP maneuvers augmented coherence to >0.97 at 0.05 Hz and >0.98 at 0.10 Hz in both age groups. The OLBNP protocol conclusively revealed the cerebrovascular system functions as a high-pass filter during exercise throughout aging. It was also discovered that the older adults had elevations (+71%) in normalized gain (+0.46 ± 0.36%/%: 0.05 Hz) and reductions (−34%) in phase (−0.24 ± 0.22 radian: 0.10 Hz). There were also age-related phase differences between resting and exercise conditions. It is speculated that these age-related changes in the TFA metrics are mediated by alterations in vasoactive factors, sympathetic tone, or the mechanical buffering of the compliance vessels. PMID:26586907

  7. Effects of citrinin on iron-redox cycle.

    Science.gov (United States)

    Da Lozzo, Eneida Janiscki; Mangrich, Antonio Salvio; Rocha, Maria Eliane Merlin; de Oliveira, Maria Benigna Martinelli; Carnieri, Eva Gunilla Skare

    2002-03-01

    The ability of the mycotoxin citrinin to act as an inhibitor of iron-induced lipoperoxidation of biological membranes prompted us to determine whether it could act as an iron chelating agent, interfering with iron redox reactions or acting as a free radical scavenger. The addition of Fe3+ to citrinin rapidly produced a chromogen, indicating the formation of citrinin-Fe3+ complexes. An EPR study confirms that citrinin acts as a ligand of Fe3+, the complexation depending on the [Fe3+]:[citrinin] ratios. Effects of citrinin on the iron redox cycle were evaluated by oxygen consumption or the o-phenanthroline test. No effect on EDTA-Fe2+-->EDTA-Fe3+ oxidation was observed in the presence of citrinin, but the mycotoxin inhibited, in a dose-dependent manner, the oxidation of Fe2+ to Fe3+ by hydrogen peroxide. Reducing agents such as ascorbic acid and DTT reduced the Fe3+-citrinin complex, but DTT did not cause reduction of Fe3+-EDTA, indicating that the redox potentials of Fe3+-citrinin and Fe3+-EDTA are not the same. The Fe2+ formed from the reduction of Fe3+-citrinin by reducing agents was not rapidly reoxidized to Fe3+ by atmospheric oxygen. Citrinin has no radical scavenger ability as demonstrated by the absence of DPPH reduction. However, a reaction between citrinin and hydrogen peroxide was observed by UV spectrum changes of citrinin after incubation with hydrogen peroxide. It was also observed that citrinin did not induce direct or reductive mobilization of iron from ferritin. These results indicate that the protective effect on iron-induced lipid peroxidation by citrinin occurs due to the formation of a redox inactive Fe3+-citrinin complex, as well as from the reaction of citrinin and hydrogen peroxide. Copyright 2001 John Wiley & Sons, Ltd.

  8. Martensite Aging Effect and Thermal Cyclic Characteristics in Ti-Pd and Ti-Pd-Ni High Temperature Shape Memory Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in Ms and Af temperatures in Ti50Pd50-xNix(x=10, 20, 30)alloys, but no obvious thermal cycling effect was observed in Ti50Pd50Pd40Ni10 alloys and the aging effect shows a curious feature, i.e.,the Af temperature does not saturate even after relatively long time aging, which is considered to be due to the occurrence of recovery recrystallization during aging.

  9. Effects of Heterogeneous Vegetation on the Surface Hydrological Cycle

    Institute of Scientific and Technical Information of China (English)

    ZHOU Suoquan; CHEN Jingming; GONG Peng; XUE Genyuan

    2006-01-01

    Using the three-layer variable infiltration capacity (VIC-3L) hydrological model and the successive interpolation approach (SIA) of climate factors, the authors studied the effect of different land cover types on the surface hydrological cycle. Daily climate data from 1992 to 2001 and remotely-sensed leaf area index (LAI) are used in the model. The model is applied to the Baohe River basin, a subbasin of the Yangtze River basin, China, with an area of 2500 km2. The vegetation cover types in the Baohe River basin consist mostly of the mixed forest type (~85%). Comparison of the modeled results with the observed discharge data suggests that: (1) Daily discharges over the period of 1992-2001 simulated with inputs of remotely-sensed land cover data and LAI data can generally produce observed discharge variations, and the modeled annual total discharge agrees with observations with a mean difference of 1.4%. The use of remote sensing images also makes the modeled spatial distributions of evapotranspiration physically meaningful. (2) The relative computing error (RCE) of the annual average discharge is -24.8% when the homogeneous broadleaf deciduous forestry cover is assumed for the watershed. The error is 21.8% when a homogeneous cropland cover is assumed and -14.32% when an REDC (Resource and Environment Database of China) land cover map is used. The error is reduced to 1.4% when a remotely-sensed land cover at 1000-m resolution is used.

  10. Effect of ageing on colonic mucosal regeneration

    Institute of Scientific and Technical Information of China (English)

    Ferenc Sipos; Katalin Leiszter; Zsolt Tulassay

    2011-01-01

    The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium. On the one hand, age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation, which results in epithelial damage. On the other hand, the altered migration and function of regenerative stem cells, the age-related methylation of mucosal healing-associated genes, together with the alterations of growth factor signaling with age, may be involved in delayed mucosal regeneration. The connections of these alterations to the process of ageing are not fully known. The understanding and customtailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies. Here, we aim to summarize the age-related microscopic and molecular changes of the human colon, as well as their role in altered mucosal healing.

  11. Prevalence of premenstrual syndrome among women of child-bearing age with regular menstrual cycle

    Directory of Open Access Journals (Sweden)

    Nodira Khodjaeva

    2013-11-01

    Full Text Available The study on prevalence of premenstrual syndrome (PMS with various severities was conducted in a cohort of fertile female residents of Tashkent aged from 18 to 30. Clinical and medical history data on psycho-emotional and physical PMS symptoms was put into a specially developed card-questionnaire. Severity of symptoms was determined by total score to fill in a PMS symptom scale on the basis of the examinees’ self-observation. The associations of PMS with social-demographic factors, such as, level of education, employment status, sexual satisfaction and stress index were analyzed.

  12. The Age of Reason: Financial Decisions over the Life-Cycle with Implications for Regulation

    OpenAIRE

    Laibson, David I.; Agarwal, Sumit; Driscoll, John C.; Gabaix, Xavier

    2009-01-01

    Many consumers make poor financial choices and older adults are particularly vulnerable to such errors. About half of the population between ages 80 and 89 either has dementia or a medical diagnosis of “cognitive impairment without dementia.†We study lifecycle patterns in financial mistakes using a proprietary database that measures ten different types of credit behavior. Financial mistakes include suboptimal use of credit card balance transfer offers, misestimation of the value of one’...

  13. The effect of electrical passive cycling on spasticity in war veterans with SCI (Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Seyed M Rayegani

    2011-06-01

    Full Text Available Introduction: Muscle atrophy, spasticity and deformity are among long term complication of Spinal Cord Injury(SCI veterans. There are numerous studies evaluating effect of functional electrical stimulation (FES on muscle properties of SCI people, but less research has focused on the benefits of passive cycling in the management of spasm and improving ROM of lower limbs in individuals with SCI. Aims: To evaluate the effect of electrical passive cycling on passive range of movement spasticity and electrodiagnostic parameters in SCI veterans. Methods: 64 SCI veterans referred to two clinical and research center in Tehran were recruited in this prospective clinical trial. The subjects were divided into 2 groups according to electrical passive cycling usage: 1 patients who didn’t use pedal exercise(control group, 2 patients used Electrical passive cycling up to optimal level (intervention group . Main outcome measures included hip, knee and ankle rang of motion, spacticity scale, and electrodiagnostic parameters including F-Wave Consistency, F-Wave Amplitude, H/M Ratio, F/M Ratio, H Reflex Onset Latency and H Reflex Amplitude. Data were recorded at the time of receiving and one year after pedal exercise usage. Results : Sixty four SCI patients including 95.3% male, 4.7% female with mean age 43 years old were included in this study. All patients except one had complete SCI suffered from complete SCI. The involved spinal levels were cervical(17.2%, upper thoracic (34.4%, lower thoracic (45.3% and lumbar (3.1%. Spasticity scale decreased significantly after passive cycling in group 2 and 3. Also hip, knee and ankle ROM in group 2 and 3 were significantly improved after pedal exercise. There was a significant difference in H max/M max (RT< and F/M ratio after versus before electric passive cycling system in group 2. Conclusion: These findings suggest that passive rythmic leg exercise can lead to decrease in spasticity ,increase in passive ROM of low

  14. Recovery from Cycling Exercise: Effects of Carbohydrate and Protein Beverages

    Directory of Open Access Journals (Sweden)

    Christopher J. Womack

    2012-06-01

    Full Text Available The effects of different carbohydrate-protein (CHO + Pro beverages were compared during recovery from cycling exercise. Twelve male cyclists (VO2peak: 65 ± 7 mL/kg/min completed ~1 h of high-intensity intervals (EX1. Immediately and 120 min following EX1, subjects consumed one of three calorically-similar beverages (285–300 kcal in a cross-over design: carbohydrate-only (CHO; 75 g per beverage, high-carbohydrate/low-protein (HCLP; 45 g CHO, 25 g Pro, 0.5 g fat, or low-carbohydrate/high-protein (LCHP; 8 g CHO, 55 g Pro, 4 g fat. After 4 h of recovery, subjects performed subsequent exercise (EX2; 20 min at 70% VO2peak + 20 km time-trial. Beverages were also consumed following EX2. Blood glucose levels (30 min after beverage ingestion differed across all treatments (CHO > HCLP > LCHP; p < 0.05, and serum insulin was higher following CHO and HCLP ingestion versus LCHP. Peak quadriceps force, serum creatine kinase, muscle soreness, and fatigue/energy ratings measured pre- and post-exercise were not different between treatments. EX2 performance was not significantly different between CHO (48.5 ± 1.5 min, HCLP (48.8 ± 2.1 min and LCHP (50.3 ± 2.7 min. Beverages containing similar caloric content but different proportions of carbohydrate/protein provided similar effects on muscle recovery and subsequent exercise performance in well-trained cyclists.

  15. Menstrual cycle effects on psychological symptoms in women with PTSD.

    Science.gov (United States)

    Nillni, Yael I; Pineles, Suzanne L; Patton, Samantha C; Rouse, Matthew H; Sawyer, Alice T; Rasmusson, Ann M

    2015-02-01

    The menstrual cycle has been implicated as a sex-specific biological process influencing psychological symptoms across a variety of disorders. Limited research exists regarding the role of the menstrual cycle in psychological symptoms among women with posttraumatic stress disorder (PTSD). The current study examined the severity of a broad range of psychological symptoms in both the early follicular (Days 2-6) and midluteal (6-10 days postlutenizing hormone surge) phases of the menstrual cycle in a sample of trauma-exposed women with and without PTSD (N = 49). In the sample overall, total psychological symptoms (d = 0.63), as well as depression (d = 0.81) and phobic anxiety (d = 0.81) symptoms, specifically, were increased in the early follicular compared to midluteal phase. The impact of menstrual cycle phase on phobic anxiety was modified by a significant PTSD × Menstrual Phase interaction (d = 0.63). Women with PTSD reported more severe phobic anxiety during the early follicular versus midluteal phase, whereas phobic anxiety did not differ across the menstrual cycle in women without PTSD. Thus, the menstrual cycle appears to impact fear-related symptoms in women with PTSD. The clinical implications of the findings and future research directions are discussed.

  16. Age effects in Okun's law within the Eurozone

    DEFF Research Database (Denmark)

    Hutengs, O.; Stadtmann, G.

    2013-01-01

    We estimate Okun's coefficients for five different age cohorts for several Eurozone countries. We find a stable pattern for all countries: the relationship between business cycle fluctuations and the unemployment rate is the strongest for the youngest cohort and gets smaller for the elderly cohorts....

  17. Gompertz law and aging as exclusion effects.

    Science.gov (United States)

    Hallén, Anund

    2007-10-01

    The exponential increase with age in mortality rate, the Gompertz law, indicates that the decrease in vitality and viability linked to aging depends on phenomena with exponential or logarithmic dynamics. Gompertz slope (alpha) is assumed to be a measure of aging rate, provided the studied cohort is homogeneous and in a supporting environment. The law provides no clue about the cause of aging, but may be formally correlated with various physical or mathematical functions. A possible correlation between the Ogston-Laurent exclusion equation and human aging is examined. An increase with age of an inert cross-linked insoluble protein network is assumed to result in a logarithmic decrease in water volume available to colloidal macromolecules. In this model, alpha is assumed to be a measure of the rate of accumulation of the polypeptide network.

  18. Life-cycle effects of alcoholism on education, earnings, and occupation.

    Science.gov (United States)

    Mullahy, J; Sindelar, J

    1989-01-01

    In this article we examine the life-cycle effects of alcoholism on human capital formation and labor market outcomes. We attempt empirically to unravel some of the complicated structural relationships among family background, educational attainment, labor force participation, earnings, and current as well as past alcoholism. Access to a new data set allows us to study some of these relationships. The Epidemiological Catchment Area data set contains not only the standard socioeconomic and demographic variables but also information on family background and age of onset of symptoms and current alcoholism. Thus, when estimating models of occupational choice and earnings, we can assess both the indirect and the direct effects of alcoholism. We find that early onset of alcoholism significantly retards educational attainment.

  19. Age of acquisition effects in vocabulary learning.

    Science.gov (United States)

    Palmer, Shekeila D; Havelka, Jelena

    2010-11-01

    Two experiments examined whether the age of acquisition (AoA) of a concept influences the speed at which native English speakers are able to name pictures using a newly acquired second language (L2) vocabulary. In Experiment 1, participants were taught L2 words associated with pictures. In Experiment 2 a second group of participants were taught the same words associated with L1 translations. Following training both groups performed a picture naming task in which they were asked to name pictures using the newly acquired words. Significant AoA effects were observed only in Experiment 1, in that participants were faster at naming pictures representing early acquired relative to late acquired concepts. The results suggest that the AoA of a concept can exert influence over processing which is independent of the AoA of the word form. The results also indicate that different training methods may lead to qualitative differences in the nature of the links formed between words and concepts during the earliest stages of second language learning.

  20. Effects of the climate change in the hydrologic cycle

    Science.gov (United States)

    Arreguin Cortés, F.; López Pérez, M.

    2010-03-01

    Among the different effects resulting from the Climate Change around the world related to the water cycle those that account more are the drought and the flooding. Also the water supply sources is expected to diminished or polluted, wetlands tend to disappear and aquatic environments degrade, population is expected to be displaced because of the increase in sea level in deltaic zones and a lowering in health standards related to water diseases due to extreme meteorological phenomena and new climatic conditions. That the climate has changed in México is a fact and its features are the increase in seasonal temperature (winter and summer) as well as a reduction in summer precipitation in central and northern Mexico coupled to an increase in winter in the northwestern regions. More frequent severe storms in different Mexican regions (southeastern and central Mexico) and in urban areas like Mexico City and the gradual reduction in the water flowing in rivers are also evidence of this change. The National Water Commission has developed studies using maximum and minimum temperature and daily precipitation analysis from a new data base called Maya v1 which accounts for a regular network that covers the entire country. Also coastal aquifer studies, hurricane strikes incidence and identification of specific areas in water basins with major vulnerability (closely related to urban and rural settlements invading floodplains and water courses) are underway. Some studies and actions that need to be developed and taken are indicated and an example of coordinated work is shown. In addition a set of adaptation measures to take according to the regional situation is described. Such measures should focus on the present situation as well as for the future and need to be studied and foreseen now. If such measures are quickly taken in those vulnerable areas the costs they represent will be less compared with the costs of the damages due to the presence of the hydrometeorological

  1. Effect of aging time and aging temperature on fatigue and fracture behavior of 6063 aluminum alloy under seawater influence

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, R.A. [Department of Mechanical and Industrial Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khod 123 (Oman); Abdul-Wahab, S.A. [Department of Mechanical and Industrial Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khod 123 (Oman)], E-mail: sabah1@squ.edu.om; Pervez, T. [Department of Mechanical and Industrial Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khod 123 (Oman)

    2008-07-01

    This paper describes experimentally the effect of seawater corrosion, aging time, and aging temperature on the fatigue resistance property of 6063 aluminum alloy. The 6063 aluminum alloy that was used for the study was heat treated and soaked in seawater for different intervals of time between 2 and 30 weeks. It was found that the maximum fatigue resistance property in the 6063 aluminum alloy was observed when aged between 7 and 9 h and heat treated at temperatures between 160 {sup o}C and 200 {sup o}C. Generally at constant load, the results indicated that the number of cycles to fail the 6063 aluminum alloy decreased with increasing the soaking time in seawater. Moreover, fracture surfaces were considered and studied under a scanning electron microscope (SEM). The results showed that the brittle fracture pattern tended to occur with the increase in aging time and temperature. The fatigue striations were observed very clearly at low and peak aging temperature. The increase in the fatigue resistance property with aging time was linked with the vacancies assisted diffusion mechanism and also by the hindering of dislocation movement by impure atoms.

  2. Static Analysis of Double Effect Adsorption Refrigeration Cycle Using Silica gel/Water Pair

    Science.gov (United States)

    Marlinda; Miyazaki, Takahiko; Ueda, Yuki; Akisawa, Atsushi

    In this paper,a static analysis of double effect adsorption refrigeration cycle utilizing condensation heat is discussed. Double effect adsorption refrigeration cycle consists of two cycles, High Temperature Cycle (HTC) which is driven from external heat sources, and Low Temperature Cycle (LTC) which is driven by condensation heat from HTC. Both of HTC and LTC are using silica gel and water as working pairs. The effect of heat source temperature on cycle performance was investigated in terms of coefficient of performance (COP) and specific cooling energy (SCE). Results showed that double effect cycle would produce higher COP than single effect cycle for driving temperature observed between 80-150°C with the same operating condition. However, the value of SCE is lower than single effect, despite that the SCE of double effect cycle is improved with heat source temperature higher than 100°C. Further, it was also observed that adsorbent mass ratio of HTC and LTC affected performance of chiller. When adsorbent mass ratio of HTC and LTC was unity, it was found that SCE and COP took the maximum.

  3. Effects of additive noise on the stability of glacial cycles

    CERN Document Server

    Mitsui, Takahito

    2016-01-01

    It is well acknowledged that the sequence of glacial-interglacial cycles is paced by the astronomical forcing. However, how much is the sequence robust against natural fluctuations associated, for example, with the chaotic motions of atmosphere and oceans? In this article, the stability of the glacial-interglacial cycles is investigated on the basis of simple conceptual models. Specifically, we study the influence of additive white Gaussian noise on the sequence of the glacial cycles generated by stochastic versions of several low-order dynamical system models proposed in the literature. In the original deterministic case, the models exhibit different types of attractors: a quasiperiodic attractor, a piecewise continuous attractor, strange nonchaotic attractors, and a chaotic attractor. We show that the combination of the quasiperiodic astronomical forcing and additive fluctuations induce a form of temporarily quantised instability. More precisely, climate trajectories corresponding to different noise realiza...

  4. Effects of nitrogen deposition on soil sulfur cycling

    Science.gov (United States)

    Chen, Hao; Yang, Liqiong; Wen, Li; Luo, Pan; Liu, Lu; Yang, Yi; Wang, Kelin; Li, Dejun

    2016-11-01

    Increased atmospheric nitrogen (N) deposition has been found to alter processes and functions of terrestrial ecosystems including the biogeochemical cycling of N and other elements, e.g., phosphorus (P), calcium (Ca), and potassium (K). Nevertheless, how N deposition changes sulfur (S) cycling is largely unknown. Based on a meta-analysis and a lab N addition experiment, here we show that N addition significantly suppresses the activity of soil arylsulfatase, which is a major enzyme involved in the mineralization of organic S. The evidence suggests that N-induced decrease in soil pH is responsible for the decrease of arylsulfatase activity. Soil buffering capacity plays a critical role in mediating the extent of arylsulfatase activity response to N inputs via its regulation on soil pH. Our results suggest that N deposition may slow down S cycling by suppressing soil organic S mineralization.

  5. Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

    CERN Document Server

    Althouse, L P

    1979-01-01

    Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

  6. Cycle simulation of the low-temperature triple-effect absorption chiller with vapor compression unit

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.S.; Lee, H.

    1999-07-01

    The construction of a triple-effect absorption chiller machine using the lithium bromide-water solution as a working fluid is strongly limited by corrosion problems caused by the high generator temperature. In this work, three new cycles having the additional vapor compression units were suggested in order to lower the generator temperature of a triple-effect absorption chiller. Each new cycle has one compressor located at the different position which was used to elevate the pressure of the refrigerant vapor. Computer simulations were carried out in order to examine both the basic triple-effect cycle and three new cycles. All types of triple-effect absorption chiller cycles were found to be able to lower the temperature of high-temperature generator to the more favorable operation range. The COPs of three cycles calculated by considering the additional compressor works showed a small level of decrease or increase compared with that of the basic triple-effect cycle. Consequently, a low-temperature triple-effect absorption chiller can be possibly constructed by adapting one of three new cycles. A great advantage of these new cycles over the basic one is that the conventionally used lithium bromide-water solution can be successfully used as a working fluid without the danger of corrosion.

  7. Aging and memory effect in magnetoelectric gallium ferrite single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vijay; Mukherjee, Somdutta [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Mitra, Chiranjib [Department of Physics, Indian Institute of Science Education and Research, Kolkata 741252 (India); Garg, Ashish [Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Gupta, Rajeev, E-mail: guptaraj@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-02-01

    Here, we present a time and temperature dependent magnetization study to understand the spin dynamics in flux grown single crystals of gallium ferrite (GaFeO{sub 3}), a known magnetoelectric, ferroelectric and ferrimagnet. Results of the magnetic measurements conducted in the field-cooled (FC) and zero-field-cooled (ZFC) protocols in the heating and cooling cycles were reminiscent of a “memory” effect. Subsequent time dependent magnetic relaxation measurements carried out in ZFC mode at 30 K with an intermittent cooling to 20 K in the presence of a small field show that the magnetization in the final wait period tends to follow its initial state which was present before the cooling break taken at 20 K. These observations provide an unambiguous evidence of single crystal gallium ferrite having a spin glass like phase. - Highlights: • Gallium ferrite a room temperature magnetoelectric and ferrimagnetic material. • Spin‐glass like phase at low temperatures below ∼200 K. • Observation of memory and aging effects in GFO.

  8. Effect of women's age on embryo morphology, cleavage rate and competence-A multicenter cohort study

    DEFF Research Database (Denmark)

    Grøndahl, Marie Louise; Christiansen, Sofie Lindgren; Kesmodel, Ulrik Schiøler

    2017-01-01

    .0001) with increasing age. Maternal age had no effect on cleavage parameters or on the morphology of the embryo day 2 post insemination. Interestingly, initial hCG value after single embryo transfer followed by ongoing pregnancy was increased with age in both IVF (p = 0.007) and ICSI (p = 0.001) cycles. For the first...... time, we show that a woman's age does impose a significant footprint on early embryo morphological development (3PN). In addition, the developmentally competent embryos were associated with increased initial hCG values as the age of the women increased. Further studies are needed to elucidate......, if this increase in initial hCG value with advancing maternal age is connected to the embryo or the uterus....

  9. Effectiveness of the Vital Aging program to promote active aging in Mexican older adults.

    Science.gov (United States)

    Mendoza-Ruvalcaba, Neyda Ma; Fernández-Ballesteros, Rocío

    2016-01-01

    Aging is not only a population phenomenon but also an experience and an individual reality. Vital Aging(®) is a program that considers active aging as the lifelong adaptation process of maximizing health and independence, physical and cognitive functioning, positive affect regulation and control, and social engagement. Through its different versions and editions, it has demonstrated being an effective program to promote active aging. The aim of this study is to determine the effectiveness of the "face-to-face" and "combined" versions of the program to promote active aging in Mexican older adults trial. Seventy-six older adults aged 60 years and over participated in a quasi-experimental study and were recruited in a senior center to participate in the two experimental conditions: Vital Aging face-to-face (VA-FF) (n=35) and Vital Aging combined (VA-C; multimedia/face-to-face) (n=15), and the remaining 26 adults were assigned to a control group. Pretest and posttest assessments were performed after the theoretical-practical intervention. Mean differences and size effects were calculated for estimating the effect of the program. At the end of the study, participants showed improvements in the active aging outcome measures. Positive effects were observed in the frequency of intellectual, cultural - artistic, and social activities, perceptions of aging, satisfaction with social relationships, and self-efficacy for aging. Additionally, those who participated in VA-FF showed better memory performance, meta-memory, and a trend to report less memory problems, while older persons in VA-C showed a trend to have better life satisfaction. No effects were observed in physical activity, frequency of social relationships, and subjective health. Findings show that the Vital Aging program in face-to-face and combined versions encourages active aging in Mexican older persons. These results are in general similar to those found in editions performed in Spain, revealing its consistency

  10. Redox Couples with Unequal Diffusion Coefficients: Effect on Redox Cycling

    NARCIS (Netherlands)

    Mampallil Augustine, Dileep; Mathwig, Klaus; Kang, Shuo; Lemay, Serge G.

    2013-01-01

    Redox cycling between two electrodes separated by a narrow gap allows dramatic amplification of the faradaic current. Unlike conventional electrochemistry at a single electrode, however, the mass-transport-limited current is controlled by the diffusion coefficient of both the reduced and oxidized fo

  11. Skin Cancer, Irradiation, and Sunspots: The Solar Cycle Effect

    Directory of Open Access Journals (Sweden)

    Edward Valachovic

    2014-01-01

    Full Text Available Skin cancer is diagnosed in more than 2 million individuals annually in the United States. It is strongly associated with ultraviolet exposure, with melanoma risk doubling after five or more sunburns. Solar activity, characterized by features such as irradiance and sunspots, undergoes an 11-year solar cycle. This fingerprint frequency accounts for relatively small variation on Earth when compared to other uncorrelated time scales such as daily and seasonal cycles. Kolmogorov-Zurbenko filters, applied to the solar cycle and skin cancer data, separate the components of different time scales to detect weaker long term signals and investigate the relationships between long term trends. Analyses of crosscorrelations reveal epidemiologically consistent latencies between variables which can then be used for regression analysis to calculate a coefficient of influence. This method reveals that strong numerical associations, with correlations >0.5, exist between these small but distinct long term trends in the solar cycle and skin cancer. This improves modeling skin cancer trends on long time scales despite the stronger variation in other time scales and the destructive presence of noise.

  12. Effects of cycling training at imposed low cadences

    DEFF Research Database (Denmark)

    Hansen, Ernst A.; Rønnestad, Bent R.

    2017-01-01

    cadence. Eighty rpm can for example be considered a low cadence if effort is maximal. On the other hand, the cadence has to be lower than 80 rpm (e.g. 40-70 rpm) to be considered low if cycling is performed at low power output. The reason is that the choice of cadence is dependent on power output...

  13. Relative Age Effects in Dutch Adolescents : Concurrent and Prospective Analyses

    NARCIS (Netherlands)

    Jeronimus, Bertus F.; Stavrakakis, Nikolaos; Veenstra, Rene; Oldehinkel, Albertine J.

    2015-01-01

    The literature on relative age position effects is rather inconsistent. In this study we examined intra-classroom age position (or relative age) effects on Dutch adolescents' school progress and performance (as rated by teachers), physical development, temperamental development (fear and frustration

  14. The Relative Age Effect among Female Brazilian Youth Volleyball Players

    Science.gov (United States)

    Okazaki, Fabio H. A.; Keller, Birgit; Fontana, Fabio E.; Gallagher, Jere D.

    2011-01-01

    In sports, the relative age effect (RAE) refers to performance disadvantages of children born late in the competition year compared to those with birthdays soon after the cutoff date. This effect is derived from age grouping, a strategy commonly used in youth sport programs. The purpose of age grouping is to decrease possible cognitive, physical,…

  15. The Relative Age Effect among Female Brazilian Youth Volleyball Players

    Science.gov (United States)

    Okazaki, Fabio H. A.; Keller, Birgit; Fontana, Fabio E.; Gallagher, Jere D.

    2011-01-01

    In sports, the relative age effect (RAE) refers to performance disadvantages of children born late in the competition year compared to those with birthdays soon after the cutoff date. This effect is derived from age grouping, a strategy commonly used in youth sport programs. The purpose of age grouping is to decrease possible cognitive, physical,…

  16. Study on Variants of Solution Treatment and Aging Cycle of Titanium Alloy Ti6Al4V

    Science.gov (United States)

    Gupta, R. K.; Kumar, V. Anil; Chhangani, Sumit

    2016-04-01

    Ti6Al4V with two different chemical compositions, one rich and the other lean in α-stabilizer oxygen were selected to study the effect of quench severity during solution treatment and their aging response. These two coupons were taken from two differently processed wrought products viz. rolled ring and closed die forging. The coupons were then subjected to solution treatment followed by employing different cooling rates to vary the quench severity and different aging treatments by changing the aging temperature and time. The microstructure and mechanical properties thus obtained are correlated with respect to the heat treatment conditions. It is noted that there is a significant increase in strength of the alloy retaining the ductility when it is aged in the aging temperature regime of 550-650 °C and time of 8 h. Role of higher oxygen content is noted, which is more pronounced with higher severity of quench (by water quenching). Specimens representative of different heat treatment conditions were characterized using optical microscope, electron back-scattered diffraction, and electron microscope. The presence of martensitic (α') structure along with uniform distribution of fine primary α, secondary α precipitates and refined β-grains, twins in the microstructure helps in improving the strength of the material. Also, during high temperature aging of 700 °C, which incidentally falls in the range of annealing temperature of the alloy, overaging occurs which is similar to effect of annealing and hence retains the ductility as well.

  17. SOME ASPECTS OF THE TWO WAY SHAPE MEMORY EFFECT INDUCED BY PSEUDOELASTIC CYCLING IN Cu-Zn-Al ALLOYS

    OpenAIRE

    Cesari, E.; Picornell, C.; Pons, J.; Sade, M.

    1991-01-01

    The two-way shape memory effect (TWSME) induced by pseudoelastic cycling in Cu-Zn-Al single crystals has been studied. We analyzed the influence of the mechanical cycling characteristics (tensile or compressing) and of the presence of [MATH]-phase precipitates in the material. The two-way memory effect induced by compressing cycling appears after a smaller number of cycles than in tensile pseudoelastic cycling. The presence of [MATH]-phase precipitates also reduces the number of cycles needed...

  18. The effect of a caffeinated energy drink on various psychological measures during submaximal cycling.

    Science.gov (United States)

    Duncan, Michael J; Hankey, Joanne

    2013-05-27

    Caffeine containing energy drinks is commonly consumed in the belief that it will enhance the quality of an exercise session and enhance mood. However, studies examining their efficacy are sparse. The aim of this study was to examine the effect of a caffeinated energy drink on leg pain perception, perceived exertion, mood state and readiness to invest effort pre, during and post 60 min cycling exercise. Fourteen active individuals (7 males, 7 females, mean age ± S.D.=23.5 ± 3.5 years), completed two 60 min cycling trials at an intensity of 60% VO2 max preceded by ingestion of solutions containing either a caffeinated energy drink or placebo using a double-blind, deceptive, crossover design. During exercise, RPE (6-20 scale), leg pain (0-10 scale), heart rate (HR) and blood lactate (Bla) were recorded. Participants also completed measures of mood state and readiness to invest physical effort (RTIPE) pre- and post-exercise. Repeated measures analysis of variance was used to assess differences in all variables and across time and treatments, with gender used as a between subjects variable. Results indicate that HR was significantly higher (P=.002) from 30 to 60 min and RPE (P=.0001) and pain perception (P=.0001) were significantly lower from 20 to 60 min in the energy drink condition compared to placebo. Bla was significantly higher (P=.021) in the last 15 min of the energy drink trial and RTIPE (P=.001) increased significantly more from pre-ingestion to pre-exercise post-ingestion in the energy drink condition compared to placebo. No gender differences were evident (P>.05). The data revealed positive effects of energy drink ingestion on perception of exertion, leg muscle pain perception and readiness to invest effort during submaximal cycling in active adults.

  19. Evaluation of the Effects of Menstrual Cycle on Anterior Chamber Parameters as Measured with Pentacam

    Directory of Open Access Journals (Sweden)

    Arzu Seyhan Karatepe

    2013-01-01

    Full Text Available Pur po se: To evaluate the effects of endogenous gonadotropic hormones (follicle-stimulating hormone, luteinizing hormone and sex steroids (progesterone, estrogen to anterior segment parameters. Ma te ri al and Met hod: Thirty healthy females who had a menstrual cycle of 28±1 day and with a mean age of 36.5±7.56 (range, 20 – 46 years were included in the study. Starting from the first day of their cycle, Pentacam Scheimpflug camera measurements were performed on the 1st, 3rd, 7th, 12th, 16th, 21st, 26th, and 28th days. The central corneal thickness, anterior chamber depth, anterior segment volume, keratometric values, anterior chamber angle value, and pupilla diameter of both eyes were evaluated. Repeated measures analysis of variance test was used for statistical analysis. Re sults: No difference that reaches statistical significance was found in the means of central corneal thickness, anterior chamber volume, keratometric values, anterior chamber angle, and pupilla diameter between the days. Mean anterior chamber depth measurement of the right eyes on the 1st day was 2.72±0.44 mm, whereas it was 2.77±0.46 mm on the 26th day. Mean anterior chamber depth measurement of the left eyes on the 1st day was 2.74±0.42 mm, whereas it was 2.80±0.43 mm on the 26th day. This increment of anterior chamber depth value from the 1st to the 26th days was found to be statistically significant (p≤0.05. Dis cus si on: Progesterone and estrogen that rise in the second half of the menstrual cycle might have a deepening effect on the anterior chamber. These findings should be further investigated with more profound studies that also evaluate the hormonal values and their correlations with anterior segment parameters. (Turk J Ophthalmol 2013; 43: 15-8

  20. Poverty and life cycle effects: A nonparametric analysis for Germany

    OpenAIRE

    Stich, Andreas

    1996-01-01

    Most empirical studies on poverty consider the extent of poverty either for the entire society or for separate groups like elderly people.However, these papers do not show what the situation looks like for persons of a certain age. In this paper poverty measures depending on age are derived using the joint density of income and age. The density is nonparametrically estimated by weighted Gaussian kernel density estimation. Applying the conditional density of income to several poverty measures ...

  1. Effects of Hygrothermal Cycling on the Chemical, Thermal, and Mechanical Properties of 862/W Epoxy Resin

    Science.gov (United States)

    Miller, Sandi G.; Roberts, Gary D.; Copa, Christine C.; Bail, Justin L.; Kohlman, Lee W.; Binienda, Wieslaw K.

    2011-01-01

    The hygrothermal aging characteristics of an epoxy resin were characterized over 1 year, which included 908 temperature and humidity cycles. The epoxy resin quickly showed evidence of aging through color change and increased brittleness. The influence of aging on the material s glass transition temperature (Tg) was evaluated by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The Tg remained relatively constant throughout the year long cyclic aging profile. The chemical composition was monitored by Fourier Transform Infrared Spectroscopy (FTIR) where evidence of chemical aging and advancement of cure was noted. The tensile strength of the resin was tested as it aged. This property was severely affected by the aging process in the form of reduced ductility and embrittlement. Detailed chemical evaluation suggests many aging mechanisms are taking place during exposure to hygrothermal conditions. This paper details the influence of processes such as: advancement of cure, chemical degradation, and physical aging on the chemical and physical properties of the epoxy resin.

  2. Effect of face familiarity on age decision.

    Science.gov (United States)

    Bruyer, Raymond; Mejias, Sandrine; Doublet, Sophie

    2007-02-01

    The present experiment was planned to check whether the extraction of apparent age is affected by face identity (familiarity) or not. According to the traditional view, age estimation should be carried out independently of face identity, because it is one of the visually derived semantic codes (like gender and ethnicity). However, little is known about its underlying mechanisms. Moreover, some recent studies have cast doubt on the parallel thesis regarding facial expression, facial speech, ethnicity, and gender. Given the promising results of a pilot experiment (n=24), 16 Caucasian participants were enrolled in an "age decision" task on morphed faces derived from one old and one young source-face, in the proportion 70:30. The respondents had previously been familiarised with half the source faces by a learning procedure (associating the face, surname, occupation and city of residence of the person displayed), while the remaining half were unfamiliar. The results showed that age decision was affected by face familiarity, at least when the task was perceptually difficult enough. This adds support to the thesis that the identification of identity and the extraction of visually derived semantic codes are not made independently from each other. The status of age, within the visually derived semantic codes, is also discussed.

  3. Effect of age on ocular microtremor activity.

    Science.gov (United States)

    Bolger, C; Bojanic, S; Sheahan, N F; Coakley, D; Malone, J F

    2001-06-01

    Ocular microtremor (OMT) is a high-frequency tremor of the eyes. It is present in all individuals and is related to brainstem activity. The OMT signal appears as an irregular oscillatory movement with intermittent burst-like components. The clinical interest in OMT has centered on its use in the assessment of the comatose patient, with broad agreement among authors of its prognostic value. The purpose of this study was to examine the changes in OMT activity related to aging. OMT was recorded from 72 normal healthy subjects using the piezoelectric strain gauge technique. The subjects ranged in age from 21 to 88 years (54.22 +/- 20.43 years, mean +/- SD). Our results show that the overall frequency and frequency content of the bursts falls with age (p < .002 and p < .001, respectively). There is a highly significant drop in all three frequency parameters of OMT (p < .0001) in subjects older than 60 years of age. These results suggest that different values of normality should operate for subjects over 60 years of age when considering the clinical application of OMT.

  4. The lunar cycle: effects of full moon on renal colic.

    Science.gov (United States)

    Molaee Govarchin Ghalae, Hojjat; Zare, Samad; Choopanloo, Maryam; Rahimian, Roya

    2011-01-01

    To evaluate renal colic frequency in different seasons and around full moon. A total of 1481 patients with renal colic were studied retrospectively addressing days of a month both in solar and lunar calendar. The mean age of the patients was 57 ± 13 years. Total admissions in summer was 613; of which 288 (41%), 199 (39%), and 126 (43%) were in years 2002, 2003, and 2004, respectively. The highest frequencies in solar calendar were on days 2 (56), 20 (63), and 27 (59) and the lowest were on days 6 (36), 22 (38), 26 (34), and 31 (31). We did not find any statistically significant association according to solar calendar (P = .3). In lunar calendar, most of the admissions were on day 15 (69) and the lowest rates were on days 1 (25) and 30 (26), which was statistically significant (P = .04). Renal colic frequency is not correlated with solar calendar, but its highest frequency in lunar calendar is in the middle of the month period. Although we found a correlation between full moon effect and renal tide, but this is a new window for further studies.

  5. Biomechanical assessments of the effect of visual feedback on cycling for patients with stroke.

    Science.gov (United States)

    Lin, Sang-I; Lo, Chao-Chen; Lin, Pei-Yi; Chen, Jia-Jin J

    2012-08-01

    Stroke patients exhibit abnormal pattern in leg cycling exercise. The aim of this study was to investigate the effects of visual feedback on the control of cycling motion in stroke patients from kinesiological, kinematic and kinetic aspects. The cycling performance derived from cycling electromyography (EMG), cycling cadence, and torque of forty stroke subjects was evaluated under conditions with and without visual feedback of cycling cadence. Kinesiological indices, shape symmetry index (SSI) and area symmetry index (ASI) were extracted from EMG linear envelopes to evaluate the symmetry of muscle firing patterns during cycling. Roughness index (RI) was calculated from cycling cadence to represent cycling smoothness from kinematic aspects. Averaged cycling power (Pav), the product of cadence and torque, was used to represent force output. The rectus femoris EMG showed significantly greater ASI with visual feedback, however, the difference in SSI between the two conditions was not significant. For the biceps femoris, there was a significant decrease in SSI with visual feedback, while the ASI was not affected significantly by the task conditions. The cycling smoothness was better and the average power generated was larger when visual feedback was provided. This study found that the addition of visual feedback improved both neuromuscular control and overall performance. Such improvement is likely to be the result of better control of the rectus femoris muscle activation and coordination of both legs.

  6. Anxiolytic-like effects of restraint during the dark cycle in adolescent mice.

    Science.gov (United States)

    Ota, Yuki; Ago, Yukio; Tanaka, Tatsunori; Hasebe, Shigeru; Toratani, Yui; Onaka, Yusuke; Hashimoto, Hitoshi; Takuma, Kazuhiro; Matsuda, Toshio

    2015-05-01

    Stress during developmental stage may cause psychological morbidities, and then the studies on stress are important in adolescent rodents. Restraint is used as a common stressor in rodents and the effects of restraint during the light cycle have been studied, but those of restraint during the dark cycle have not. The present study examined the effects of restraint during the light and dark cycles on anxiety behaviors in adolescent mice. Restraint for 3h during either the light or dark cycle impaired memory function in the fear conditioning test, but did not affect locomotor activity. In the elevated plus-maze test, restraint during the dark cycle reduced anxiety-like behaviors in mice. Repeated exposure to a 3-h period dark cycle restraint for 2 weeks had a similar anxiolytic-like effect. In contrast, restraint for 3h during the light cycle produced anxiety behavior in adolescent, but not adult, mice. The light cycle stress increased plasma corticosterone levels, and elevated c-Fos expression in the prefrontal cortex, paraventricular hypothalamic nucleus, basolateral amygdala and dentate gyrus, and enhanced serotonin turnover in the hippocampus and striatum, while the dark cycle stress did not. There was no difference in the stress-mediated reduction in pentobarbital-induced sleeping time between dark and light cycle restraint. These findings suggest that the anxiolytic effect of dark cycle restraint is mediated by corticosterone, serotonin or γ-aminobutyric acid-independent mechanisms, although the anxiogenic effect of light cycle restraint is associated with changes in plasma corticosterone levels and serotonin turnover in specific brain regions.

  7. The effect of age on thymic function

    Directory of Open Access Journals (Sweden)

    Donald B. Palmer

    2013-10-01

    Full Text Available Age-related regression of the thymus is associated with a decline in naïve T cell output. This is thought to contribute to the reduction in T cell diversity seen in older individuals and linked with increased susceptibility to infection, autoimmune disease and cancer. Thymic involution is one of the most dramatic and ubiquitous changes seen in the ageing immune system, but the mechanisms which underlying this process are poorly understood. However, a picture is emerging, implicating the involvement of both extrinsic and intrinsic factors. In this review we assess the role of the thymic microenvironment as a potential target that regulates thymic involution, question whether thymocyte development in the aged thymus is functionally impaired and explore the kinetics of thymic involution.

  8. Isothermal aging effects on PMR-15 resin

    Science.gov (United States)

    Bowles, Kenneth J.; Jayne, Douglas; Leonhardt, Todd A.

    1993-01-01

    Specimens of PMR-15 polyimide neat resin were aged in air at temperatures of 288, 316, and 343 C. Weight losses and dimensional changes were monitored during the course of the exposure time. Physical changes were also observed by optical and electron microscopy. It was found that polyimide polymer degradation occurred within a thin surface layer that developed and grew during thermal aging. The cores of the polymer specimens were protected from oxidative degradation, and they were relatively unchanged by the thermal treatment. Surface cracking was observed at 343 C and was probably due to an interaction between voids and stresses that developed in the surface layer.

  9. Rapamycin extends murine lifespan but has limited effects on aging.

    Science.gov (United States)

    Neff, Frauke; Flores-Dominguez, Diana; Ryan, Devon P; Horsch, Marion; Schröder, Susanne; Adler, Thure; Afonso, Luciana Caminha; Aguilar-Pimentel, Juan Antonio; Becker, Lore; Garrett, Lillian; Hans, Wolfgang; Hettich, Moritz M; Holtmeier, Richard; Hölter, Sabine M; Moreth, Kristin; Prehn, Cornelia; Puk, Oliver; Rácz, Ildikó; Rathkolb, Birgit; Rozman, Jan; Naton, Beatrix; Ordemann, Rainer; Adamski, Jerzy; Beckers, Johannes; Bekeredjian, Raffi; Busch, Dirk H; Ehninger, Gerhard; Graw, Jochen; Höfler, Heinz; Klingenspor, Martin; Klopstock, Thomas; Ollert, Markus; Stypmann, Jörg; Wolf, Eckhard; Wurst, Wolfgang; Zimmer, Andreas; Fuchs, Helmut; Gailus-Durner, Valérie; Hrabe de Angelis, Martin; Ehninger, Dan

    2013-08-01

    Aging is a major risk factor for a large number of disorders and functional impairments. Therapeutic targeting of the aging process may therefore represent an innovative strategy in the quest for novel and broadly effective treatments against age-related diseases. The recent report of lifespan extension in mice treated with the FDA-approved mTOR inhibitor rapamycin represented the first demonstration of pharmacological extension of maximal lifespan in mammals. Longevity effects of rapamycin may, however, be due to rapamycin's effects on specific life-limiting pathologies, such as cancers, and it remains unclear if this compound actually slows the rate of aging in mammals. Here, we present results from a comprehensive, large-scale assessment of a wide range of structural and functional aging phenotypes, which we performed to determine whether rapamycin slows the rate of aging in male C57BL/6J mice. While rapamycin did extend lifespan, it ameliorated few studied aging phenotypes. A subset of aging traits appeared to be rescued by rapamycin. Rapamycin, however, had similar effects on many of these traits in young animals, indicating that these effects were not due to a modulation of aging, but rather related to aging-independent drug effects. Therefore, our data largely dissociate rapamycin's longevity effects from effects on aging itself.

  10. Effect of wetting-drying cycles on soil desiccation cracking behaviour

    Directory of Open Access Journals (Sweden)

    Tang Chao-Sheng

    2016-01-01

    Full Text Available Better understanding the desiccation cracking process is essential in analysing drought effects on soil hydraulic and mechanical properties through consideration of the atmosphere-ground interaction. Laboratory tests were conducted to investigate the consequence of wetting-drying cycles on the initiation and propagation characteristics of desiccation cracks on soil surface. Initially saturated slurry specimens were prepared and subjected to five subsequent wetting-drying cycles. Image processing technique was employed to quantitatively analyze the morphology characteristics of crack patterns formed during each drying path. The results show that the desiccation cracking behaviour of soil is significantly affected by the wetting-drying cycles. Before the third wetting-drying cycle is reached, the surface crack ratio and the average crack width increases while the average clod area decreases with increasing the number of wetting-drying cycles. The number of intersections and crack segments per unit area reaches the peak values after the second wetting-drying cycle. After the third wetting-drying cycle is reached, the effect of increasing wetting-drying cycles on crack patterns is insignificant. Moreover, it is observed that the applied wetting-drying cycles are accompanied by a continual reconstruction of soil structure. The initial homogenous slurry structure is completely replaced with aggregated structure after the third cycles, and a significant increase in the inter-aggregate porosity can be observed.

  11. Effective Parameters on Performance of Multipressure Combined Cycle Power Plants

    OpenAIRE

    Thamir K. Ibrahim; Rahman, M M

    2014-01-01

    A parametric analysis is performed for numerous configurations of a combined cycle gas turbine (CCGT) power plant, including single-pressure, double-pressure, triple-pressure, triple-pressure with reheat, and supplementary triple-pressure with reheat. The compression ratio of the gas turbine and the steam pressure of the steam turbine are taken as design parameters. The thermodynamic model was developed based on an existing MARAFIQ CCGT power plant and performance model code developed using t...

  12. Effects of complex life cycles on genetic diversity: cyclical parthenogenesis.

    Science.gov (United States)

    Rouger, R; Reichel, K; Malrieu, F; Masson, J P; Stoeckel, S

    2016-11-01

    Neutral patterns of population genetic diversity in species with complex life cycles are difficult to anticipate. Cyclical parthenogenesis (CP), in which organisms undergo several rounds of clonal reproduction followed by a sexual event, is one such life cycle. Many species, including crop pests (aphids), human parasites (trematodes) or models used in evolutionary science (Daphnia), are cyclical parthenogens. It is therefore crucial to understand the impact of such a life cycle on neutral genetic diversity. In this paper, we describe distributions of genetic diversity under conditions of CP with various clonal phase lengths. Using a Markov chain model of CP for a single locus and individual-based simulations for two loci, our analysis first demonstrates that strong departures from full sexuality are observed after only a few generations of clonality. The convergence towards predictions made under conditions of full clonality during the clonal phase depends on the balance between mutations and genetic drift. Second, the sexual event of CP usually resets the genetic diversity at a single locus towards predictions made under full sexuality. However, this single recombination event is insufficient to reshuffle gametic phases towards full-sexuality predictions. Finally, for similar levels of clonality, CP and acyclic partial clonality (wherein a fixed proportion of individuals are clonally produced within each generation) differentially affect the distribution of genetic diversity. Overall, this work provides solid predictions of neutral genetic diversity that may serve as a null model in detecting the action of common evolutionary or demographic processes in cyclical parthenogens (for example, selection or bottlenecks).

  13. Effects of Intergenerational Interaction on Aging

    Science.gov (United States)

    Hernandez, Carmen Requena; Gonzalez, Marta Zubiaur

    2008-01-01

    The world population pyramid has changed shape. However, this does not mean that societies have changed their negative concept of old age. Our study proposes an intergenerational service-learning program with 179 university students and 101 slightly depressed elderly people. The results show that the elderly people who interacted improved in…

  14. Effective recordkeeping technologies to manage aging

    Energy Technology Data Exchange (ETDEWEB)

    Dukelow, J.S.; Johnson, A.B. Jr. (Pacific Northwest Lab., Richland, WA (United States)); Vora, J.P. (Nuclear Regulatory Commission, Washington, DC (United States))

    1992-10-01

    Pacific Northwest Laboratory has investigated the capability of current recordkeeping technology to support aging management. This paper discusses technical issues associated with potential enhancements of nuclear plant records systems--from the perspective of the lessons learned about equipment aging degradation mechanisms and associated surveillance and monitoring techniques during the U. S. Nuclear Regulatory Commission's Nuclear Plant Aging Research Program. The paper considers both the specific types of technical data needed to ensure continued safe operation and the use of new technology to upgrade record systems. Specific topics discussed include: equipment reliability data needed to support the assessment of the impact of aging on the continued operation of the plant; operational history data to support the assessment of residual life of mechanical and structural components and piping; tools for the analysis and trending of equipment reliability data and operational history data; design and implementation of plant record systems that will provide a comprehensive and usable engineering design basis for the plant; proposed improvements in the data input process for the plant records system; computerization of plant records systems, including conversion of existing records into machine-readable forms.

  15. Effective recordkeeping technologies to manage aging

    Energy Technology Data Exchange (ETDEWEB)

    Dukelow, J.S.; Johnson, A.B. Jr. [Pacific Northwest Lab., Richland, WA (United States); Vora, J.P. [Nuclear Regulatory Commission, Washington, DC (United States)

    1992-10-01

    Pacific Northwest Laboratory has investigated the capability of current recordkeeping technology to support aging management. This paper discusses technical issues associated with potential enhancements of nuclear plant records systems--from the perspective of the lessons learned about equipment aging degradation mechanisms and associated surveillance and monitoring techniques during the U. S. Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program. The paper considers both the specific types of technical data needed to ensure continued safe operation and the use of new technology to upgrade record systems. Specific topics discussed include: equipment reliability data needed to support the assessment of the impact of aging on the continued operation of the plant; operational history data to support the assessment of residual life of mechanical and structural components and piping; tools for the analysis and trending of equipment reliability data and operational history data; design and implementation of plant record systems that will provide a comprehensive and usable engineering design basis for the plant; proposed improvements in the data input process for the plant records system; computerization of plant records systems, including conversion of existing records into machine-readable forms.

  16. Adult age effects in auditory statistical learning

    NARCIS (Netherlands)

    Neger, T.M.; Rietveld, A.C.M.; Janse, E.

    2015-01-01

    Statistical learning plays a key role in language processing, e.g., for speech segmentation. Older adults have been reported to show less statistical learning on the basis of visual input than younger adults. Given age-related changes in perception and cognition, we investigated whether statistical

  17. Effects of Age on Second Language Acquisition

    Institute of Scientific and Technical Information of China (English)

    张娜

    2013-01-01

      Many factors associated with learners when acquiring a second language influence the chances of Second Language Acquisition (SLA). These not only include internal factors as learners’personality characteristics but social factors that also have a major impact on language proficiency. The paper focus on the age factor through the Critical Period Hypothesis and give implications after an analysis.

  18. Effects of Aging on the Respiratory System.

    Science.gov (United States)

    Levitzky, Michael G.

    1984-01-01

    Relates alterations in respiratory system functions occurring with aging to changes in respiratory system structure during the course of life. Main alterations noted include loss of alveolar elastic recoil, alteration in chest wall structure and decreased respiratory muscle strength, and loss of surface area and changes in pulmonary circulation.…

  19. Age Effects on Positive and Negative Emotions.

    Science.gov (United States)

    Barrick, Ann Louise; And Others

    Although emotions have been widely studied, researchers have rarely focused on the elderly. Consequently, many questions remain unanswered concerning the emotions of older adults. This study examined age differences in emotional intensity of short- and long-term emotion. Older adults (N=61) and younger adult college students (N=93) completed the…

  20. Ageing effect of chloride diffusion coefficient

    NARCIS (Netherlands)

    Polder, R.B.

    2006-01-01

    Most of the currently used models to predict chloride ingress a constant diffusion coefficient over time. However, a reduction of the diffusion coefficient over time, is ob-served at specimens that are exposed to chlorides. This reduction of the diffusion coefficient is expressed with the ageing coe

  1. Organizational Life Cycles and Shifting Criteria of Effectiveness: Some Preliminary Evidence

    OpenAIRE

    Robert E. Quinn; Kim Cameron

    1983-01-01

    This paper discusses the relationships between stage of development in organizational life cycles and organizational effectiveness. We begin the paper by reviewing nine models of organizational life cycles that have been proposed in the literature. Each of these models identifies certain characteristics that typify organizations in different stages of development. A summary model of life cycle stages is derived that integrates each of these nine models. Next, a framework of organizational eff...

  2. The effects of weight cycling on lifespan in male C57BL/6J mice

    OpenAIRE

    List, Edward O.; Berryman, Darlene E.; Wright-Piekarski, Jacob; Jara, Adam; Kopchick, John J.

    2012-01-01

    Objective With the increasing rates of obesity, many people diet in attempts to lose weight. Since weight loss is seldom maintained in a single effort, weight cycling is a common occurrence. Unfortunately, reports from clinical studies that have attempted to determine the effect of weight cycling on mortality are in disagreement, and to date, no controlled animal study has been performed to assess the impact of weight cycling on longevity. Therefore, our objective was to determine whether wei...

  3. Effect of age on aortic atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    Michael A. Chen; Miwa Kawakubo; Patrick M. Colletti; Dongxiang Xu; Laurie LaBree Dustin; Robert Detrano; Stanley P Azen; Nathan D. Wong; Xue-Qiao Zhao

    2013-01-01

    Objective To examine the association of atherosclerosis burden in the survivors of an asymptomatic elderly cohort study and its relationship to other coronary risk factors (specifically, age) by evaluating aortic atherosclerotic wall burden by magnetic resonance imaging (MRI). Methods A total of 312 participants in an ongoing observational cohort study underwent cardiac and descending thoracic aorta imaging by MRI. Maximum wall thickness was measured and the mean wall thickness calculated. Wall/outer wall ratio was used as a normalized wall index (NWI) adjusted for artery size difference among participants. Percent wall volume (PWV) was calculated as NWI × 100. Results In this asymptomatic cohort (mean age: 76 years), the mean (SD) aortic wall area and wall thickness were 222 ± 45 mm2 and 2.7 ± 0.4 mm, respectively. Maximum wall thickness was 3.4 ± 0.6 mm, and PWV was 32% ± 4%. Women appeared to have smaller wall area, but after correcting for their smaller artery size, had significantly higher PWV than men (P = 0.03). Older age was associated with larger wall area (P = 0.04 for trend) with similar PWVs. However, there were no statistically significant associations between standard risk factors, Framingham global risk, or metabolic syndrome status, therapy for cholesterol or hypertension, coronary or aortic calcium score, and the aortic wall burden. Aortic calcification was associated with coronary calcification. Conclusions Asymptomatic elderly in this cohort had a greater descending thoracic aortic wall volume that correlated with age, and women had a significantly increased PWV compared to men. In these survivors, the atherosclerotic aortic wall burden was not significantly associated with traditional risk factors or with coronary or aortic calcium scores or coronary calcium progression. Results suggest that age, or as yet unidentified risk factor(s), may be responsible for the increase in atherosclerosis.

  4. The relation between the duty cycle and anesthetic effect in lidocaine iontophoresis using alternating current.

    Science.gov (United States)

    Wakita, Ryo; Nakajima, Atsushi; Haida, Yu; Umino, Masahiro; Fukayama, Haruhisa

    2011-01-01

    We assessed the effect of the duty cycle on the anesthetic effect during lidocaine alternating current (AC) iontophoresis. A solution of 2% lidocaine was delivered to the medial antecubital skin for 20 minutes using AC iontophoresis with a duty cycle of 60%, 70%, or 80%. The von Frey test was then performed to evaluate the anesthetic effect. In the groups treated with a duty cycle of 80% or 70% the touch thresholds (TT) were significantly elevated from 0 minutes to 30 minutes and from 0 minutes to 20 minutes. TT were significantly elevated at 0 minutes in the group treated with a 60% duty cycle. The anesthetic effect was significantly enhanced in a duty cycle-dependent manner.

  5. Effect of higher strain range cycling on near fatigue-limit fatigue life

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, Chie; Nakagawa, Y.G. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan). Research Inst; Rosinski, S.T.

    1999-04-01

    The objective of this study is to clarify the effects of pre-cycling above the fatigue limit on near the fatigue-limit fatigue behaviors of SA508, low alloy steel for nuclear pressure vessels, correlating fatigue lifetime with microstructural changes in the bulk. It has been observed that dislocation cell structure is well developed in an as-received SA508 sample and the misorientation among cells increases with fatigue accumulation during fatigue tests. The cell to cell misorientation was measured and statistically quantified by the Selected Area electron beam Diffraction (SAD). It was shown that a fatigue crack started growing abruptly when the SAD value (the mean misorientation among cells) exceeded a critical angle, 4-5 degrees. Fatigue tests were performed for SA508 samples, first at a high total strain range (0.62%) to 10, 100, and 6000 cycles followed by cycling at near the fatigue-limit strain range (0.40%). The sample with pre-cycling for 100 and 6000 cycles failed while ones with pre-cycling for 10 cycles and without pre-cycling did not rupture till about 10{sup 6} cycles where the tests were terminated. Small surface cracks were found all samples pre-cycled at the high strain range but the cracks were arrested for a long time at the near fatigue limit cycling followed by an abrupt growth at the failure. It was found by the SAD that samples failed at the fatigue limit when the average misorientation among cells exceeds the critical angle regardless of pre-cycling histories. The SAD value changed even during cycling below the fatigue limit, and the change in SAD value was strongly influenced by the number of pre-cycling above the fatigue limit. These changes well agreed with fatigue lifetime of the samples. (author)

  6. Perceptions toward cycling in Zagreb area: Differences concerning age, gender and membership in the association “Trade Union of Cyclists”

    OpenAIRE

    Joško Sindik; Vladimir Halgota; Mislav Kirac; Tena Šarić; Marko Gregović

    2013-01-01

    Bicycle riding today is a widespread form of traffic, but the conditions for cycling in Zagreb, although improved, are still not satisfactory. The aim of this study was to determine gender differences along with differences in the perceptions of members of the association of Cyclists trade union with a “typical” Zagreb cyclist, in terms of various factors relating to the problems of cycling in Zagreb. The correlation between these perceptions and the age of the participants was studied. Over ...

  7. Effect of Estradiol Prescribed during Luteal Phase of Art Cycles and Pregnancy Outcome

    Directory of Open Access Journals (Sweden)

    M Karimzadeh

    2007-01-01

    Full Text Available Introduction: Implantation is one of the most important steps in ART cycles and it depends upon embryo and endometrial reception. Different protocols have been suggested for getting better endometrium. It seems estrogen increases the endometrial reception and pregnancy rate by inducing changes in the hormonal status. The aim of this study was to evaluate the effect of estradiol(E2 on luteal phase support and pregnancy rate in ART cycles Methods: This prospective randomized study was done in Yazd at the IVF center from March until December, 2002. 68 patients who had undergone IVF or ICSI were enrolled in the study. Exclusion criteria was age>40, endometriosis and ovarian hyper stimulation syndrome. Induction ovulation protocol was long suppression with GnRH analogues.After embryo transfer, patients were divided in two groups randomly. Both groups received 100mg progesterone IM daily from the transfer day. Estradiol valerate 2 mg/day was added from the 7th transfer day to progesterone in Group I and continued if the BhCG became positive. Abortion and malformations were measured in all patients. Data analyzed with SPSS 11.0 and P value <0.05 considered statistically significant. Results: Pregnancy rate in the 34 patients of estradiol group (group I was 26.5%which was significantly higher than 11.8 %( 4 cases in the other group (Pvalue=0.034. Abortion rate was higher in estradiol group (3 cases, but there was no abortion in the progesterone group(P=0.119. 2 cases of major fetal malformations were observed in E2 supplementation group (P=0.246 . Conclusions: E2 suplementation to progesterone in the luteal phase of ART cycles, especially in the long GnRH analogues causes higher endometrial receptivity and pregnancy rate.

  8. Hypogravity's Effect on the Life Cycle of Japanese Quail

    Science.gov (United States)

    Hester, Patricia Y.

    1999-01-01

    A series of studies were conducted to determine the effect of activities preceding space-flight and during space-flight on quail embryonic development. While the overall development of the quail embryos was evaluated, the report presented herein, focused on calcium utilization or uptake from eggshells by developing embryos during incubation in space and on earth. In the pre-space trials, fertilized quail eggs were subjected to pre-night dynamics including forces of centrifugation, vibration, or a combination of vibration and centrifugation prior to incubation for 6 or 16 days. In another trial, fertile quail eggs were tested for survivability in a refrigerator stowage kit for eggs (RSKE) which was subsequently used to transport the eggs to space. Eggs in the RSKE were subjected to shuttle launch dynamics including G force and random vibration profiles. In the space- flight trials, 48 fertile quail eggs were launched on space shuttle Flight STS-76 and were subsequently incubated in a Slovakian incubator onboard space station, MIR. Two sets of ground controls each with 48 fertile eggs with and without exposure to launch dynamics were initiated 5 days post-launch. There was a laboratory control (incubated in Lyon RX2 incubator at 37.5 C) and a synchronous control (incubated in Lyon RX2 incubator at 39 - 400 C), which simulated the temperature of the space-flight incubator. Following space-flight trials, post-flight trials were conducted where quail eggs were incubated in Lyon RX2 or Slovakian incubators under various temperatures with or without launch dynamics. Eggshells from all study trials were retrieved and analyzed for calcium content to determine if its utilization by developing quail embryos was affected by activities preceding space-flight or during incubation in space under microgravity. Results from the pre-flight and post-flight showed that pre-flight activities and shuttle launch dynamics had no effect on calcium uptake from the eggshell by developing

  9. Effectiveness of the Vital Aging program to promote active aging in Mexican older adults

    Directory of Open Access Journals (Sweden)

    Mendoza-Ruvalcaba NM

    2016-11-01

    Full Text Available Neyda Ma Mendoza-Ruvalcaba,1 Rocío Fernández-Ballesteros2 1Health Sciences Department, University of Guadalajara, University Center of Tonalá, Tonalá, Jalisco, Mexico; 2Department of Biological and Health Psychology, Autonomous University of Madrid, Madrid, Spain Introduction: Aging is not only a population phenomenon but also an experience and an individual reality. Vital Aging® is a program that considers active aging as the lifelong adaptation process of maximizing health and independence, physical and cognitive functioning, positive affect regulation and control, and social engagement. Through its different versions and editions, it has demonstrated being an effective program to promote active aging. The aim of this study is to determine the effectiveness of the “face-to-face” and “combined” versions of the program to promote active aging in Mexican older adults trial. Methods: Seventy-six older adults aged 60 years and over participated in a quasi-experimental study and were recruited in a senior center to participate in the two experimental conditions: Vital Aging face-to-face (VA-FF (n=35 and Vital Aging combined (VA-C; multimedia/face-to-face (n=15, and the remaining 26 adults were assigned to a control group. Pretest and posttest assessments were performed after the theoretical–practical intervention. Mean differences and size effects were calculated for estimating the effect of the program. Results: At the end of the study, participants showed improvements in the active aging outcome measures. Positive effects were observed in the frequency of intellectual, cultural – artistic, and social activities, perceptions of aging, satisfaction with social relationships, and self-efficacy for aging. Additionally, those who participated in VA-FF showed better memory performance, meta-memory, and a trend to report less memory problems, while older persons in VA-C showed a trend to have better life satisfaction. No effects were

  10. Effects of aging on motor cortex excitability.

    Science.gov (United States)

    Oliviero, A; Profice, P; Tonali, P A; Pilato, F; Saturno, E; Dileone, M; Ranieri, F; Di Lazzaro, V

    2006-05-01

    To determine whether aging is associated with changes in excitability of the cerebral cortex, we evaluated the excitability of the motor cortex with transcranial magnetic stimulation (TMS). We compared TMS related measures obtained in a group of young people with those of a group of old people. Motor evoked potential (MEP) amplitude was significantly smaller in older than in younger controls (1.3+/-0.8 mV versus 2.7+/-1.1 mV; p<0.0071). Mean cortical silent period (CSP) duration was shorter in older than in younger controls (87+/-29 ms versus 147+/-39 ms; p<0.0071). SP duration/MEP amplitude ratios were similar in both groups. Our results are consistent with an impaired efficiency of some intracortical circuits in old age.

  11. Effect of aging on penile ultrastructure

    Institute of Scientific and Technical Information of China (English)

    Zhou-Jun SHEN; Xiao-Dong JIN; Zhao-Dian CHEN; Yuan-He SHI

    2001-01-01

    Aim: To clarify whether there are anatomical changes in tunica albuginea and corpora cavemosa in aged rats. Methods: Seventeen male Sprague-Dawley rats were divided into three groups based on age. Group A consisted of young rats (9 weeks), Group B, middle aged rats (14 weeks) and Group C, old rats (62 weeks). The penile samples were obtained and observed under a scanning electron microscope. Results: The thickness (mean ± SD) of the tunica albuginea was 0.14 ± 0.02, 0.16 ± 0.03 and 0.06 ± 0.02 mm in Groups A, B and C, respectively. The tunica albuginea of group C was significantly thinner than those of the other two groups ( P < 0.05) and the elastic fibers were diminished in the old rats. In the corpora cavemosa of old rats, the intracavemous pillars were irregular, in which many large collagen fibers could be observed, and the smooth muscle and elastic fibers were reduced. Conclusion: In old rats, the tunica albuginea became thinner with diminished elastic fibers; the collagen fibers of corpora cavemosa were increased while the smooth muscle and elastic fibers were reduced.

  12. [Measuring the estrus cycle and its effect on superovulation in mice].

    Science.gov (United States)

    Zhu, Na; Jia, Hong-Xiang; Liu, Xiao-Kun; Zhao, Xiao-E; Wei, Qiang; Ma, Bao-Hua

    2012-06-01

    This study compares superovulation efficiency during different stages of the estrus cycle in mice by investigating the pudendum appearance, vaginal epithelial cell type, and the follicular development dynamics, in relation to the estrus cycle. We determined the stages of the estrus cycle by observing the pudendum and making vaginal smears of the Kunming mouse, and ascertaining the follicular development by making paraffin sections. Based on the observation, mice in stages of proestrus, oestrus, metoestrus and dioestrus were superovulated respectively, and their follicular developments and embryo collection results were tracked to ascertain the appropriate estrus cycle stage for superovulation. Our data showed that pudendum appearance and vaginal smears could effectively distinguish different stages of the estrus cycle and that ovarian tissue observation showed that follicular development, corpus luteum formation and luteolysis were regular during the estrus cycle. Likewise, during the estrus cycle of the Kunming mouse, pudendum appearance, vaginal epithelial cell type and follicular development were relational to one another. Superovulating mice in different stages of the estrus cycle showed marked differences both in pregnancy rate and average number of embryos collected. Proestrus was significantly better than metoestrus and dioestrus (P0.05). We suggest that pudendum appearance and vaginal smears can be used to distinguish estrus cycle stages and that proestrus is the optimal stage of the estrus cycle for superovulation.

  13. Effects of the seasonal cycle on superrotation in planetary atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Jonathan L. [Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095 (United States); Vallis, Geoffrey K. [College of Engineering, Mathematics and Physical Science, Exeter University, Exeter (United Kingdom); Potter, Samuel F. [Atmospheric and Oceanic Sciences Program, Princeton University, NJ 08544 (United States)

    2014-05-20

    The dynamics of dry atmospheric general circulation model simulations forced by seasonally varying Newtonian relaxation are explored over a wide range of two control parameters and are compared with the large-scale circulation of Earth, Mars, and Titan in their relevant parameter regimes. Of the parameters that govern the behavior of the system, the thermal Rossby number (Ro) has previously been found to be important in governing the spontaneous transition from an Earth-like climatology of winds to a superrotating one with prograde equatorial winds, in the absence of a seasonal cycle. This case is somewhat unrealistic as it applies only if the planet has zero obliquity or if surface thermal inertia is very large. While Venus has nearly vanishing obliquity, Earth, Mars, and Titan (Saturn) all have obliquities of ∼25° and varying degrees of seasonality due to their differing thermal inertias and orbital periods. Motivated by this, we introduce a time-dependent Newtonian cooling to drive a seasonal cycle using idealized model forcing, and we define a second control parameter that mimics non-dimensional thermal inertia of planetary surfaces. We then perform and analyze simulations across the parameter range bracketed by Earth-like and Titan-like regimes, assess the impact on the spontaneous transition to superrotation, and compare Earth, Mars, and Titan to the model simulations in the relevant parameter regime. We find that a large seasonal cycle (small thermal inertia) prevents model atmospheres with large thermal Rossby numbers from developing superrotation by the influences of (1) cross-equatorial momentum advection by the Hadley circulation and (2) hemispherically asymmetric zonal-mean zonal winds that suppress instabilities leading to equatorial momentum convergence. We also demonstrate that baroclinic instabilities must be sufficiently weak to allow superrotation to develop. In the relevant parameter regimes, our seasonal model simulations compare favorably to

  14. Effects of Aging and Education on False Memory

    Science.gov (United States)

    Lee, Yuh-Shiow; Lee, Chia-Lin; Yang, Hua-Te

    2012-01-01

    This study examined the effects of aging and education on participants' false memory for words that were not presented. Three age groups of participants with either a high or low education level were asked to study lists of semantically related words. Both age and education were found to affect veridical and false memory, as indicated in the…

  15. The Flynn Effect and Population Aging

    Science.gov (United States)

    Skirbekk, Vegard; Stonawski, Marcin; Bonsang, Eric; Staudinger, Ursula M.

    2013-01-01

    Although lifespan changes in cognitive performance and Flynn effects have both been well documented, there has been little scientific focus to date on the net effect of these forces on cognition at the population level. Two major questions moving beyond this finding guided this study: (1) Does the Flynn effect indeed continue in the 2000s for…

  16. Effect of the menstrual cycle on background parenchymal enhancement observed on breast MRIs in Korean women

    Energy Technology Data Exchange (ETDEWEB)

    Park, Vivan Young Jean; KIm, Eun Kyung; Moon, Hee Jung; Yoon, Jung Hyun; Kim, Min Jung [Dept. of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2015-09-15

    To evaluate the effect of the menstrual cycle on background parenchymal enhancement observed on breast MRIs in Korean women, and to suggest an optimal period for scheduling breast MRIs. Between March and December 2012, 214 premenopausal breast cancer patients who underwent breast MRIs for preoperative evaluation were included. Levels of background parenchymal enhancement were retrospectively compared according to the menstrual cycle. There was no significant difference between levels of background parenchymal enhancement (minimal, mild, moderate, and marked) according to the weeks of the menstrual cycle. However, the 1st and 2nd week of the menstrual cycle showed a significantly higher proportion of patients with minimal background parenchymal enhancement than the 3rd and 4th week of the menstrual cycle (47.0% vs. 32.0%; p = 0.025). For screening purposes and for the follow-up of Korean breast cancer patients, breast MRIs should be performed during the 1st or 2nd week of the menstrual cycle.

  17. THE EFFECT OF ALUM AND METALS ON PAPER AGING

    Institute of Scientific and Technical Information of China (English)

    ByungHo Yoon; KyoungHwa Choi; MyoungKu Lee; SeJong Kim

    2004-01-01

    Books and archives experience aging which is affected by a variety of factors, such as microorganism, humidity, light and components of paper [1]. Thus, the studies concerning impacts of those factors on paper aging are required. In this paper, an accelerated paper aging was carried out to investigate the effects of acid and metals such as alum, copper ( Ⅱ ) sulfate, copper ( Ⅱ ) chloride, and iron (Ⅲ) chloride on paper aging. It was found that both acid and metals had impacts on paper aging. In particular, paper aging was far more accelerated in case that acid and metals were present in paper at the same time.

  18. Effect of aging on glutathione metabolism. Protection by antioxidants.

    Science.gov (United States)

    Viña, J; Sastre, J; Anton, V; Bruseghini, L; Esteras, A; Asensi, M

    1992-01-01

    The free radical theory of aging suggests that oxygen free radicals may be involved in the aging process. Thus, changes in antioxidant mechanisms may occur with aging. Since glutathione is one of the most effective antioxidant systems in the cell, its metabolism may change with aging. In this chapter we describe experiments which show the involvement of glutathione in the aging process and which provide a rationale for the administration of antioxidants to old organisms to protect them against some of the changes that occur with aging.

  19. THE EFFECT OF ALUM AND METALS ON PAPER AGING

    Institute of Scientific and Technical Information of China (English)

    Byun~HoYoo~; KyoungHwaChoi; MyoungKuLee; SeJongKim

    2004-01-01

    Books and archives experience aging which isaffected by a variety of factors, such asmicroorganism, humidity, light and components ofpaper [l]. Thus, the studies concerning impacts ofthose factors on paper aging are required. In thispaper, an accelerated paper aging was carried out toinvestigate the effects of acid and metals such asalum, copper ( 11 ) sulfate, copper ( 1] ) chloride, andiron ( IU ) chloride on paper aging. It was found thatboth acid and metals had impacts on paper aging. Inparticular, paper aging was far more accelerated incase that acid and metals were present in paper at thesame time.

  20. INTERACTIVE EFFECTS OF SOLAR UV RADIATION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLING

    Science.gov (United States)

    This paper assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are o...

  1. Mobile phone use while cycling : Incidence and effects on behaviour and safety

    NARCIS (Netherlands)

    De Waard, D.; Schepers, P.; Ormel, W.; Brookhuis, K.A.

    2010-01-01

    The effects of mobile phone use on cycling behaviour were studied. In study 1, the prevalence of mobile phone use while cycling was assessed. In Groningen 2.2% of cyclists were observed talking on their phone and 0.6% were text messaging or entering a phone number. In study 2, accident-involved

  2. Effect of snails (Elimia clavaeformis) on phosphorus cycling in stream periphyton and leaf detritus communities

    Energy Technology Data Exchange (ETDEWEB)

    Jay, E.A. [North Carolina Univ., Chapel Hill, NC (United States)

    1993-10-01

    In this study, the author examined the effect of grazing on phosphorus cycling in stream periphyton and leaf detritus communities using the snail Elimia clavaeformis. Phosphorus cycling fluxes and turnover rates were measured in a laboratory and in a natural stream, respectively, using radioactive tracer techniques.

  3. Effect of 18-h Watch Schedules on Circadian Cycles of Physiological Functions during Submarine Patrols

    Science.gov (United States)

    1978-10-01

    la degradation des cycles circadiens sous ces conditions. La duree moyenne du sommeil est diminue vers la fin du service. cycles circadiens service...en sous-marin horaire de 18 heures sommeil REFERENCES Andrezsyuk, H. I. 1968. Effects of different work and rest routines on subjects kept in

  4. Effectiveness of indometacin to prevent ovulation in modified natural-cycle IVF : A randomized controlled trial

    NARCIS (Netherlands)

    Rijken-Zijlstra, T. M.; Haadsma, M. L.; Hammer, C.; Burgerhof, J. G. M.; Pelinck, M. J.; Simons, A. H. M.; van Echten-Arends, J.; Arts, J. G. E. M.; Land, J. A.; Groen, H.; Hoek, A.

    2013-01-01

    Modified natural-cycle IVF has a lower pregnancy rate per started cycle as compared with IVF with ovarian stimulation due to, for example, premature ovulation. Indometacin administered before ovulation prevents follicle rupture. Therefore, addition of indometacin may improve the effectiveness of mod

  5. INTERACTIVE EFFECTS OF SOLAR UV RADIATION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLING

    Science.gov (United States)

    This paper assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are o...

  6. Effects of the Menstrual Cycle and Oral Contraception on Singers' Pitch Control

    Science.gov (United States)

    La, Filipa M. B.; Sundberg, Johan; Howard, David M.; Sa-Couto, Pedro; Freitas, Adelaide

    2012-01-01

    Purpose: Difficulties with intonation and vibrato control during the menstrual cycle have been reported by singers; however, this phenomenon has not yet been systematically investigated. Method: A double-blind randomized placebo-controlled trial assessing effects of the menstrual cycle and use of a combined oral contraceptive pill (OCP) on pitch…

  7. Effects of the Menstrual Cycle and Oral Contraception on Singers' Pitch Control

    Science.gov (United States)

    La, Filipa M. B.; Sundberg, Johan; Howard, David M.; Sa-Couto, Pedro; Freitas, Adelaide

    2012-01-01

    Purpose: Difficulties with intonation and vibrato control during the menstrual cycle have been reported by singers; however, this phenomenon has not yet been systematically investigated. Method: A double-blind randomized placebo-controlled trial assessing effects of the menstrual cycle and use of a combined oral contraceptive pill (OCP) on pitch…

  8. Impact of herbivores on nitrogen cycling: contrasting effects of small and large species

    NARCIS (Netherlands)

    Bakker, E.S.; Olff, H.; Boekhoff, M.; Gleichman, J.M.; Berendse, F.

    2004-01-01

    Herbivores are reported to slow down as well as enhance nutrient cycling in grasslands. These conflicting results may be explained by differences in herbivore type. In this study we focus on herbivore body size as a factor that causes differences in herbivore effects on N cycling. We used an exclosu

  9. Impact of herbivores on nitrogen cycling : contrasting effects of small and large species

    NARCIS (Netherlands)

    Bakker, ES; Olff, H; Boekhoff, M; Gleichman, JM; Berendse, F

    2004-01-01

    Herbivores are reported to slow down as well as enhance nutrient cycling in grasslands. These conflicting results may be explained by differences in herbivore type. In this study we focus on herbivore body size as a factor that causes differences in herbivore effects on N cycling. We used an exclosu

  10. Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Hiroshi, E-mail: nishi.hiroshi88@jaea.go.jp [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan); Enoeda, Mikio [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan)

    2011-10-01

    In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

  11. Physicochemical effects in aging aqueous Laponite suspensions.

    Science.gov (United States)

    Shahin, A; Joshi, Yogesh M

    2012-11-06

    We study aging behavior of an aqueous suspension of Laponite as a function of concentration of Laponite, concentration of salt, time elapsed since preparation of suspension (idle time), and temperature by carrying extensive rheological and conductivity experiments. We observe that temporal evolution of elastic moduli, which describes structural build-up and aging, shifts to low times for experiments carried out for higher concentration of Laponite, higher concentration of salt, greater temperature, and longer idle time while preserving the curvature of evolution in the solid regime (elastic modulus greater than viscous modulus). Consequently appropriate shifting of evolution of elastic modulus in the solid regime leads to aging time-idle time-salt concentration-Laponite concentration-temperature superposition. The existence of such a superposition suggests the generic nature of microstructure buildup irrespective of mentioned variables in the explored range. The behavior of shift factors needed to obtain the superposition indicate that the energy barrier associated with structural buildup decreases with an increase in idle time and temperature and decreases linearly with an increase in concentration of Laponite and that of salt. The conductivity experiments show that ionic conductivity of the suspension increases with increasing Laponite concentration, salt concentration, temperature, and very importantly the idle time. We also analyze the interparticle interactions using DLVO theory that suggests an increase in idle time, temperature, and salt concentration increases the height of the repulsive energy barrier while it decreases the width of the same when particles approach each other in a parallel fashion. However when particles approach each other in a perpendicular fashion, owing to dissimilar charges on edge and face, the energy barrier for the attractive interaction is expected to decrease with an increase in idle time, temperature, and salt concentration

  12. The cooling effect by adsorption-desorption cycles

    Directory of Open Access Journals (Sweden)

    Wolak Eliza

    2017-01-01

    Full Text Available Adsorption appliances may turn out to be an alternative to compression-type refrigerators. The adsorption refrigeration machine may be driven by a low-grade heat source, especially solar energy. Solar adsorption cooling systems are environment-friendly and have zero ozone depletion potential. Therefore, the adsorption refrigeration is one kind of energy saving refrigeration methods. The merits of the adsorption refrigeration systems will be more significant especially when it is used in vehicles (automobiles, ships and locomotives, to preserve food and medicines and in air-conditioning. The paper presents the advantages and disadvantages as well as the evolution of the technology of adsorptive refrigeration systems. The methods of improving of adsorption refrigeration systems through improvements in adsorbents properties, use of advanced cycles and hybrid systems is also presented. Possible applications and perspectives for development of adsorption cooling systems are also analyzed. The paper describes a test stand of the adsorption-desorption refrigeration. The present investigations have been carried out utilizing the activated carbon granules as an adsorbent and methanol as an adsorbate. The paper demonstrates the measurement of temperature changes in the adsorbent bed and condenser during adsorption-desorption cycles.

  13. Effect of different light-curing devices and aging procedures on composite knoop microhardness

    Directory of Open Access Journals (Sweden)

    Fernanda Regina Voltarelli

    2009-12-01

    Full Text Available The aim of this study was to evaluate the effect of light-curing devices (Halogen/HAL, Light Emitting Diodes/LED, Argon Laser/LAS and Plasma Arc/PAC and aging procedures (Mechanical Cycling/MC, Thermal Cycling/TC, Storage/S, MC+TC and MC+TC+S on the micro-hardness of bottom/B and top/T surfaces of 2-mm-high composite resin cylinders. The Knoop microhardness test (25 g, 20 s on both B and T was performed before and after each aging procedure. For B and T, before aging procedures, PAC showed reduced polymerization effectiveness when compared with HAL. In the T, after TC, PAC and LAS had also showed reduced polymerization effectiveness when compared to HAL and LED. For all light-curing devices, MC+TC+S and S affected the Knoop microhardness values. In the B, no difference could be observed among the aging procedures for PAC. From all light-curing units, PAC may have rendered composites of reduced quality and the storage aging procedures were the most harmful to the polymer hardness.

  14. Effects on the martensitic transformations and the microstructure of CuAlNi single crystals after ageing at 473 K

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, V.E.A., E-mail: aaraujo@citedef.gob.ar [Departamento de Investigaciones en Sólidos, CITEDEF, UNIDEF (MINDEF-CONICET), J.B. de La Salle 4397, (1603) Villa Martelli, Buenos Aires (Argentina); Gastien, R. [Departamento de Investigaciones en Sólidos, CITEDEF, UNIDEF (MINDEF-CONICET), J.B. de La Salle 4397, (1603) Villa Martelli, Buenos Aires (Argentina); Zelaya, E. [División Física de Metales, Centro Atómico Bariloche–CNEA, S.C. Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Beiroa, J.I.; Corro, I. [Departamento de Investigaciones en Sólidos, CITEDEF, UNIDEF (MINDEF-CONICET), J.B. de La Salle 4397, (1603) Villa Martelli, Buenos Aires (Argentina); Sade, M. [División Física de Metales, Centro Atómico Bariloche–CNEA, S.C. Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo (Argentina); Lovey, F.C. [División Física de Metales, Centro Atómico Bariloche–CNEA, S.C. Bariloche (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo (Argentina)

    2015-08-25

    Highlights: • Thermally induced martensitic transformations are studied after ageing at 473 K. • β ↔ β′ stress induced martensitic transformations were analysed after ageing at 473 K. • Pseudoelastic cycling was studied after ageing at 473 K. • Microstructure before and after ageing at 473 K was analysed using TEM. • Effect of γ precipitates and ordering processes is discussed. - Abstract: Isothermal treatments at 473 K were performed in CuAlNi single crystals to study their effects on the main properties of this shape memory material. Both the stress and thermally induced martensitic transformations were monitored after these ageing treatments. An increase of the critical transformation temperature was detected and the type of induced martensite changed from γ′ into β′ after a long enough ageing time. Pseudoelastic cycling was studied after thermal ageing; mechanical behaviour evolved on cycling and a repetitive behaviour was obtained after a small number of cycles. Changes in microstructure were analysed in the β phase by transmission electron microscopy which allowed observing the morphology and distribution of γ precipitates. The changes obtained in shape memory properties were discussed considering the atomic ordering evolution and characteristics of the precipitates.

  15. Age and Metallicity Effects in Omega Centauri

    CERN Document Server

    Hughes, J; Hughes, Joanne; Wallerstein, George

    1999-01-01

    We have observed (with vby filters) a field north of the core of the most massive globular cluster in our galaxy, Omega Centauri. We have found a correlation of age and metallicity in a region which avoids the dense core and the inhomogeneous foreground dust emission shown by the IRAS satellite. Our observations show that the comparatively metal-rich stars (as defined by the (b-y) and m_1 colors) are younger than the metal-poor stars by at least 3 Gyr. This correlation of metallicity with age suggests that Omega Cen has enriched itself over a timescale of about 3 Gyr, and possibly longer. It is remarkable that ejecta from stellar winds combined with supernovae of type II failed to disperse the cluster's interstellar matter at an earlier epoch, but were captured by the cluster instead. Star formation would have ceased as type Ia supernovae dispersed the remaining interstellar matter. This work and other recent evidence suggests that Omega Cen could have been part of a small satellite galaxy in which all the ac...

  16. Effects of Age and Age-Related Hearing Loss on the Brain

    Science.gov (United States)

    Tremblay, Kelly; Ross, Bernhard

    2007-01-01

    It is well documented that aging adversely affects the ability to perceive time-varying acoustic cues. Here we review how physiological measures are being used to explore the effects of aging (and concomitant hearing loss) on the neural representation of temporal cues. Also addressed are the implications of current research findings on the…

  17. Study on High Efficient Absorption Refrigerator Using Multi-effect Cycle

    Science.gov (United States)

    Inoue, Naoyuki; Irie, Tomoyoshi; Saito, Kiyoshi; Kawai, Sunao

    Double effect chillers are commonly used as cooling machines for air condition. Great efforts have been making to improve the efficiency for a long time, and now the COP is very near to the limitation of double effect cycles. Triple effect cycles are expected for the next step beyond double effect cycles, but have some problems of high temperature and high pressure in the high stage generator. High temperature of absorbent causes corrosion problem and high vapor pressure over atmospheric pressure causes the restriction of legal regulation. This paper deals with many types of triple effect cycles. The temperature and dew point of the high stage generator are analyzed, several types are selected for low dew point, and one of them is more analyzed in detail.

  18. Differential effects of aging and sex on stroke induced inflammation across the lifespan.

    Science.gov (United States)

    Manwani, Bharti; Liu, Fudong; Scranton, Victoria; Hammond, Matthew D; Sansing, Lauren H; McCullough, Louise D

    2013-11-01

    Aging and biological sex are critical determinants of stroke outcome. Post-ischemic inflammatory response strongly contributes to the extent of ischemic brain injury, but how this response changes with age and sex is unknown. We subjected young (5-6 months), middle aged (14-15 months) and aged (20-22 months), C57BL/6 male and female mice to transient middle cerebral artery occlusion (MCAO) and found that a significant age by sex interaction influenced histological stroke outcomes. Acute functional outcomes were worse with aging. Neutrophils, inflammatory macrophages, macrophages, dendritic cells (DCs) and microglia significantly increased in the brain post MCAO. Cycling females had higher Gr1(-) non-inflammatory macrophages and lower T cells in the brain after stroke and these correlated with serum estradiol levels. Estrogen loss in acyclic aged female mice exacerbated stroke induced splenic contraction. Advanced age increased T cells, DCs and microglia at the site of injury, which may be responsible for the exacerbated behavioral deficits in the aged. We conclude that aging and sex have differential effects on the post stroke inflammatory milieu. Putative immunomodulatory therapies need to account for this heterogeneity.

  19. Role of antioxidants in the skin: anti-aging effects.

    Science.gov (United States)

    Masaki, Hitoshi

    2010-05-01

    Intracellular and extracellular oxidative stress initiated by reactive oxygen species (ROS) advance skin aging, which is characterized by wrinkles and atypical pigmentation. Because UV enhances ROS generation in cells, skin aging is usually discussed in relation to UV exposure. The use of antioxidants is an effective approach to prevent symptoms related to photo-induced aging of the skin. In this review, the mechanisms of ROS generation and ROS elimination in the body are summarized. The effects of ROS generated in the skin and the roles of ROS in altering the skin are also discussed. In addition, the effects of representative antioxidants on the skin are summarized with a focus on skin aging.

  20. Effect of accelerated aging on translucency of monolithic zirconia

    Directory of Open Access Journals (Sweden)

    O. Abdelbary

    2016-12-01

    Conclusion: Thickness of zirconia has significant effect on translucency. Aging has significant effect on thinner sections of zirconia. More research is required on zirconia towards making the material more translucent for its potential use as esthetic monolithic restoration.

  1. Menstrual Cycle Effects on Anaerobic Power, Muscular Strength, and Muscular Endurance in Trained and Untrained Females.

    Science.gov (United States)

    Rosenburg, Beth S.; And Others

    A study determined if anaerobic power, isometric strength, and isometric endurance are affected by the menstrual cycle and if endurance trained females and untrained females are affected in the same manner on these performance parameters. Subjects were healthy, normally menstruating females, ages 18-34 years who were classified as either trained…

  2. Menstrual Cycle Effects on Anaerobic Power, Muscular Strength, and Muscular Endurance in Trained and Untrained Females.

    Science.gov (United States)

    Rosenburg, Beth S.; And Others

    A study determined if anaerobic power, isometric strength, and isometric endurance are affected by the menstrual cycle and if endurance trained females and untrained females are affected in the same manner on these performance parameters. Subjects were healthy, normally menstruating females, ages 18-34 years who were classified as either trained…

  3. Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

    National Research Council Canada - National Science Library

    Koeve, W; Kähler, P

    2010-01-01

    .... Recently, it has been suggested that the trophic nature of pelagic N2 -production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow...

  4. The effects of estrus cycle on drug metabolism in the rat.

    Science.gov (United States)

    Brandstetter, Y; Kaplanski, J; Leibson, V; Ben-Zvi, Z

    1986-01-01

    The effect of the female rat estral cycle on microsomal drug metabolism in-vivo and in-vitro has been studied. Two microsomal enzymes, aminopyrine-N-demethylase and aniline hydroxylase showed a greater specific activity (p less than 0.01) in the diestrus phase of the estral cycle while the oxidative enzyme aryl hydrocarbon hydroxylase and the conjugative enzyme, glucuronyl transferase, were not affected. In vivo studies which included theophylline and antipyrine metabolism, and hexobarbital sleeping times showed no difference between the different phases of the estral cycle. Conflicting evidence about the effect of steroid sex hormones on hepatic drug metabolism is discussed.

  5. Effect of Freeze-thaw Cycles on Bond Strength between Steel Bars and Concrete

    Institute of Scientific and Technical Information of China (English)

    JI Xiaodong; SONG Yupu; LIU Yuan

    2008-01-01

    The effect of freezing and thawing cycles on mechanical properties of concrete(compressive,splitting tensile strength)was experimentally investigated.According to the pullout test data of three kinds of deformed steel bars,the bond stress-slip curves after freezing and thawing were obtained.The empirical equations of peak bond strength were proposed that the damage accounted for effects of freezing and thawing cycle.Meanwhile,the mechanism of bond deterioration between steel bars and concrete after freezing and thawing cycles was discussed.All these conclusions will be useful to the durability design and reliability calculation of RC structures in cold region.

  6. Transparent exopolymer particles: Effects on carbon cycling in the ocean

    Science.gov (United States)

    Mari, Xavier; Passow, Uta; Migon, Christophe; Burd, Adrian B.; Legendre, Louis

    2017-02-01

    Transparent Exopolymer Particles (TEP) have received considerable attention since they were first described in the ocean more than 20 years ago. This is because of their carbon-rich composition, their high concentrations in ocean's surface waters, and especially because of their ability to promote aggregation due to their high stickiness (i.e. biological glue). As large aggregates contribute significantly to vertical carbon flux, TEP are commonly seen as a key factor that drives the downward flux of particulate organic carbon (POC). However, the density of TEP is lower than that of seawater, which causes them to remain in surface waters and even move upwards if not ballasted by other particles, which often leads to their accumulation in the sea surface microlayer. Hence we question here the generally accepted view that TEP always increase the downward flux of POC via gravitational settling. In the present reassessment of the role of TEP, we examine how the presence of a pool of non-sinking carbon-rich particulate organic matter in surface waters influences the cycling of organic carbon in the upper ocean at daily to decadal time scales. In particular, we focus on the role of TEP in the retention of organic carbon in surface waters versus downward export, and discuss the potential consequences of climate change on this process and on the efficiency of the biological carbon pump. We show that TEP sink only when ballasted with enough high-density particles to compensate their low density, and hence that their role in vertical POC export is not solely linked to their ability to promote aggregation, but also to their contribution to the buoyancy of POC. It follows that the TEP fraction of POC determines the degree of retention and remineralization of POC in surface waters versus its downward export. A high TEP concentration may temporally decouple primary production and downward export. We identify two main parameters that affect the contribution of TEP to POC cycling

  7. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    Science.gov (United States)

    Iranmanesh, A.; Mehrabian, M. A.

    2012-12-01

    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

  8. The effects of the PDCA cycle and OJT on workplace learning

    OpenAIRE

    Matsuo, Makoto; NAKAHARA, Jun

    2013-01-01

    In the present article, we examined the effects of the plan-do-check-act (PDCA) cycle and on-the-job-training (OJT) on workplace learning. We defined workplace learning based on the concept of an organizational learning cycle. Using survey data from a Japanese fire and marine insurance company, we found that PDCA, OJT (empowerment), and reflective communication had positive effects on workplace learning. These results suggest that quality management, empowerment and reflective practice may he...

  9. Performance investigation of an advanced multi-effect adsorption desalination (MEAD) cycle

    KAUST Repository

    Thu, Kyaw

    2015-12-01

    This article presents the development of an advanced adsorption desalination system with quantum performance improvement. The proposed multi-effect adsorption desalination (MEAD) cycle utilizes a single heat source i.e., low-temperature hot water (as low as 55°C). Passive heating of the feed water (no direct heating) is adopted using total internal heat recovery from the kinetic energy of desorbed vapor and water vapor uptake potential of the adsorbent. Thus, the evaporation in the MEAD cycle ensues at low temperatures ranging from 35°C to 7°C yet providing significantly high performance ratio. The energy from the regenerated vapor is recovered for multiple evaporation/condensation of saline water by a water-run-around circuit between the top brine temperature (TBT) effect and the AD condenser. The adsorbent material is the hydrophilic mesoporous silica gel with high pore surface area. Numerical simulation for such a cycle is developed based on experimentally verified model extending to multi-effect cycle. The system is investigated under several operation conditions such as cycle time allocation, heat source temperature and the number of intermediate effects. It is observed that most of the evaporating-condensing effects operate at low temperature i.e., below 35°C as opposed to conventional multi-effect distillation (MED) cycle. For a MEAD cycle with 7 intermediate effects, the specific water production rate, the performance ratio and the gain output ratio are found to be 1.0m3/htonne of silica gel, 6.3 and 5.1, respectively. Low scaling and fouling potentials being evaporation at low temperatures yet high recovery ratio makes the cycle suitable for effectively and efficiently handling highly concentrated feed water such as produced water, brine rejected from other desalination plants and zero liquid discharge (ZLD) system. © 2015 Elsevier Ltd.

  10. Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2015-01-01

    Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

  11. Effect of menstrual cycle on frequency of alveolar osteitis in women undergoing surgical removal of mandibular third molar: a single-blind randomized clinical trial.

    Science.gov (United States)

    Eshghpour, Majid; Rezaei, Naser Mohammadzadeh; Nejat, AmirHossein

    2013-09-01

    To measure the association between the menstrual cycle and the frequency of alveolar osteitis (AO). In a study with a single-blind design, patients with bilateral impacted third molar teeth underwent randomized surgical extraction: one tooth during the menstrual period and one during the middle of the cycle. The postoperative examiner was unaware of the menstrual cycle status of the patients. The predictor variable was the timing of the menstrual cycle and was grouped as mid-cycle and menstrual period. The outcome variable was AO, which was measured (without knowledge of the menstrual cycle timing) at 2 to 7 days postoperatively. Other study variables included oral contraceptive (OC) use, smoking status, irrigation used during surgery, extraction difficulty, surgeon experience, number of local anesthetic cartridges used, and patient age. Appropriate bi- and multivariate statistics were computed, and the level of statistical significance was set at P cycle than during the menstrual period inboth the OC users and nonusers (P menstrual period (P > .05). According to the results of the present study, the menstrual cycle could be a determinant risk factor in the frequency of AO. We recommend that elective procedures be performed during the menstrual period in both OC users and nonusers to eliminate the effect of cycle-related hormonal changes on the development of AO. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Effects of music tempo upon submaximal cycling performance.

    Science.gov (United States)

    Waterhouse, J; Hudson, P; Edwards, B

    2010-08-01

    In an in vivo laboratory controlled study, 12 healthy male students cycled at self-chosen work-rates while listening to a program of six popular music tracks of different tempi. The program lasted about 25 min and was performed on three occasions--unknown to the participants, its tempo was normal, increased by 10% or decreased by 10%. Work done, distance covered and cadence were measured at the end of each track, as were heart rate and subjective measures of exertion, thermal comfort and how much the music was liked. Speeding up the music program increased distance covered/unit time, power and pedal cadence by 2.1%, 3.5% and 0.7%, respectively; slowing the program produced falls of 3.8%, 9.8% and 5.9%. Average heart rate changes were +0.1% (faster program) and -2.2% (slower program). Perceived exertion and how much the music was liked increased (faster program) by 2.4% and 1.3%, respectively, and decreased (slower program) by 3.6% and 35.4%. That is, healthy individuals performing submaximal exercise not only worked harder with faster music but also chose to do so and enjoyed the music more when it was played at a faster tempo. Implications of these findings for improving training regimens are discussed.

  13. Effects of L-malate on mitochondrial oxidoreductases in liver of aged rats.

    Science.gov (United States)

    Wu, J-L; Wu, Q-P; Peng, Y-P; Zhang, J-M

    2011-01-01

    Accumulation of oxidative damage has been implicated to be a major causative factor in the decline in physiological functions that occur during the aging process. The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), considered as the pathogenic agent of many diseases and aging. L-malate, a tricarboxylic acid cycle intermediate, plays an important role in transporting NADH from cytosol to mitochondria for energy production. Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. In the present study we focused on the effect of L-malate on the activities of electron transport chain in young and aged rats. We found that mitochondrial membrane potential (MMP) and the activities of succinate dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats were significantly decreased when compared to young control rats. Supplementation of L-malate to aged rats for 30 days slightly increased MMP and improved the activities of NADH-dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats when compared with aged control rats. In young rats, L-malate administration increased only the activity of NADH-dehydrogenase. Our result suggested that L-malate could improve the activities of electron transport chain enzymes in aged rats.

  14. [Effects of polyunsaturated fatty acids on Krebs cycle in the rat kidney in chronic phosphorus intoxication].

    Science.gov (United States)

    Kulkybaev, G A; Merkusheva, N V

    1992-01-01

    The investigation of Krebs cycle state in kidney homogenates of August rats subjected to oral intoxication with oil solution of yellow phosphorus in a dose of 0.3 mg/kg, has shown that under conditions of balanced nutrition the activity of NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and accumulation of the substrate fund of the cycle decreased 3.5-fold as compared to the control. The addition of polyunsaturated fatty acids to the ration produced a positive effect on Krebs cycle state: dehydrogenase activity was not significantly changed, accumulation of Krebs cycle substrate was two-fold lower. However, this ration did not completely abolish the toxic action of yellow phosphorus on Krebs cycle.

  15. Analysis of the effect of student cognizance of the learning cycle in general chemistry

    Science.gov (United States)

    Czapla, Matthew

    While the benefits of the using the Learning Cycle have been well researched, one area that has received surprisingly little investigation is the effect that student cognizance of the learning cycle has on student performance in chemistry. The Learning Cycle, with its strong theoretical roots in scientific practice and learning theory, offers a logical opportunity to educate students in the nature of science and metacognition. In addition, by examining the class holistically, students will have the opportunity to better link the lab and lecture components of the course. We hypothesized that since a keen understanding of the nature of science, strong metacognitive ability, and a holistic view of Learning Cycle classes have all been shown to increase student comprehension in general chemistry, students who were taught to understand the Learning Cycle would perform better than students who were not. Statistical analysis of survey and grade data will be presented.

  16. The effect of changing micro-scale physical environmental factors on an environment's invitingness for transportation cycling in adults: an exploratory study using manipulated photographs.

    Science.gov (United States)

    Mertens, Lieze; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Salmon, Jo; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien; Van Cauwenberg, Jelle

    2014-08-19

    Previous studies have shown convincing evidence for positive relationships between transportation cycling in adults and macro-scale physical environmental factors. In contrast, relationships are less consistent for more changeable, micro-scale environmental factors. The majority of existing studies used observational study designs, which cannot determine causality. The present mixed-methods study used manipulated photographs to determine causal relationships between micro-scale environmental factors and the environment's invitingness for transportation cycling. Further, interactions among environmental factors and moderating effects of gender, age and educational level were investigated. For this study, panoramic photograph of a street was manipulated on eight environmental factors: traffic, speed bump, general upkeep, evenness of the cycle path, vegetation, separation of motorized traffic, separation with sidewalk and cycle path width. Sixty-six middle-aged adults participated in the study and sorted the manipulated panoramic photographs from least to most inviting to cycle for transportation. Participants also provided qualitative data on how they sorted the streets. Multilevel cross-classified modelling was used to analyse the relationships between the environmental manipulations and the invitingness-scores. The qualitative data were deductively categorized according to the environmental factors. All environmental factors, except for separation with sidewalk, proved to have a significant main effect on the invitingness-score for transportation cycling. Cycle path evenness appeared to have the strongest effect on the invitingness. This effect was even stronger in an environment with good compared to poorly overall upkeep. Another significant interaction effect showed that the invitingness decreased when both separations along the cycle path were present compared to only a separation with traffic. No moderating effects of the demographic factors on these

  17. Effectiveness of Inspiratory Termination Synchrony with Automatic Cycling During Noninvasive Pressure Support Ventilation.

    Science.gov (United States)

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2016-05-20

    BACKGROUND Pressure support ventilation (PSV) is a standard method for non-invasive home ventilation. A bench study was designed to compare the effectiveness of patient-ventilator inspiratory termination synchronization with automated and conventional triggering in various respiratory mechanics models. MATERIAL AND METHODS Two ventilators, the Respironics V60 and Curative Flexo ST 30, connected to a Hans Rudolph Series 1101 lung simulator, were evaluated using settings that simulate lung mechanics in patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or normal lungs. Ventilators were operated with automated (Auto-Trak) or conventional high-, moderate-, and low-sensitivity flow-cycling software algorithms, 5 cmH2O or 15 cmH2O pressure support, 5 cmH2O positive end-expiratory pressure (PEEP), and an air leak of 25-28 L/min. RESULTS Both ventilators adapted to the system leak without requiring adjustment of triggering settings. In all simulated lung conditions, automated cycling resulted in shorter triggering delay times (<100 ms) and lower triggering pressure-time product (PTPt) values. Tidal volumes (VT) increased with lower conventional cycling sensitivity level. In the COPD model, automated cycling had higher leak volumes and shorter cycling delay times than in conventional cycling. Asynchronous events were rare. Inspiratory time (Tinsp), peak expiratory flow (PEF), and cycling off delay time (Cdelay) increased as a result of reduction in conventional cycling sensitivity level. In the ARDS and normal adult lung models, premature cycling was frequent at the high-sensitive cycling level. CONCLUSIONS Overall, the Auto-Trak protocol showed better patient-machine cycling synchronization than conventional triggering. This was evident by shorter triggering time delays and lower PTPt.

  18. Estimation of Aging Effects on LOHS for CANDU-6

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yong Ki; Moon, Bok Ja; Kim, Seoung Rae [Nuclear Engineering Service and Solution Co. Ltd., Daejeon (Korea, Republic of)

    2014-05-15

    To evaluate the Wolsong Unit 1's capacity to respond to large-scale natural disaster exceeding design, the loss of heat sink(LOHS) accident accompanied by loss of all electric power is simulated as a beyond design basis accident. This analysis is considered the aging effects of plant as the consequences of LOHS accident. Various components of primary heat transport system(PHTS) get aged and some of the important aging effects of CANDU reactor are pressure tube(PT) diametral creep, steam generator(SG) U-tube fouling, increased feeder roughness, and feeder orifice degradation. These effects result in higher inlet header temperatures, reduced flows in some fuel channels, and higher void fraction in fuel channel outlets. Fresh and aged models are established for the analysis where fresh model is the circuit model simulating the conditions at retubing and aged model corresponds to the model reflecting the aged condition at 11 EFPY after retubing. CATHENA computer code[1] is used for the analysis of the system behavior under LOHS condition. The LOHS accident is analyzed for fresh and aged models using CATHENA thermal hydraulic computer code. The decay heat removal is one of the most important factors for mitigation of this accident. The major aging effect on decay heat removal is the reduction of heat transfer efficiency by steam generator. Thus, the channel failure time cannot be conservatively estimated if aged model is applied for the analysis of this accident.

  19. Life-Cycle Costing of Food Waste Management in Denmark: Importance of Indirect Effects

    DEFF Research Database (Denmark)

    Martinez Sanchez, Veronica; Tonini, Davide; Møller, Flemming

    2016-01-01

    Prevention has been suggested as the preferred food waste management solution compared to alternatives such as conversion to animal fodder or to energy. In this study we used societal life-cycle costing, as a welfare economic assessment, and environmental life-cycle costing, as a financial...... assessment combined with life-cycle assessment, to evaluate food waste management. Both life-cycle costing assessments included direct and indirect effects. The latter are related to income effects, accounting for the marginal consumption induced when alternative scenarios lead to different household...... expenses, and the land-use-changes effect, associated with food production. The results highlighted that prevention, while providing the highest welfare gains as more services/goods could be consumed with the same income, could also incur the highest environmental impacts if the monetary savings from...

  20. Kinetic model of mitochondrial Krebs cycle: unraveling the mechanism of salicylate hepatotoxic effects.

    Science.gov (United States)

    Mogilevskaya, Ekaterina; Demin, Oleg; Goryanin, Igor

    2006-10-01

    This paper studies the effect of salicylate on the energy metabolism of mitochondria using in silico simulations. A kinetic model of the mitochondrial Krebs cycle is constructed using information on the individual enzymes. Model parameters for the rate equations are estimated using in vitro experimental data from the literature. Enzyme concentrations are determined from data on respiration in mitochondrial suspensions containing glutamate and malate. It is shown that inhibition in succinate dehydrogenase and alpha-ketoglutarate dehydrogenase by salicylate contributes substantially to the cumulative inhibition of the Krebs cycle by salicylates. Uncoupling of oxidative phosphorylation has little effect and coenzyme A consumption in salicylates transformation processes has an insignificant effect on the rate of substrate oxidation in the Krebs cycle. It is found that the salicylate-inhibited Krebs cycle flux can be increased by flux redirection through addition of external glutamate and malate, and depletion in external alpha-ketoglutarate and glycine concentrations.

  1. The effect of volcanic eruptions on the hydrological cycle

    Science.gov (United States)

    Iles, Carley; Hegerl, Gabriele

    2015-04-01

    Large explosive volcanic eruptions inject sulphur dioxide into the stratosphere where it is oxidised to sulphate aerosols which reflect sunlight. This causes a reduction in global temperature and precipitation lasting a few years. We investigate the robust features of this precipitation response, comparing climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archive to three observational datasets, including one with ocean coverage. Global precipitation decreases significantly following eruptions in CMIP5 models, with the largest decrease in wet tropical regions. This also occurs in observational land data, and ocean data in the boreal cold season. In contrast, the dry tropical ocean regions show an increase in precipitation in CMIP5 models. Monsoon regions dry following eruptions in both models and observations, whilst in response to individual eruptions, the ITCZ shifts away from the hemisphere with the greater concentration of aerosols in CMIP5. The ocean response in CMIP5 is longer lasting than that over land, but observational results are too noisy to confirm this. We detect the influence of volcanism on precipitation in the boreal cold season, although the models underestimate the size of the response, whilst in the warm season the volcanic influence is marginally detectable. We then examine whether the influence of volcanoes can be seen in streamflow records for 50 major world rivers. Significant reductions in flow are found for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma amongst others. When neighbouring rivers are combined into regions, informed by climate model predictions of the precipitation response to eruptions, decreases in streamflow can be detected in northern South American, central African and high-latitude Asian rivers and increases in southern South American and SW North American rivers. An improved understanding of how the hydrological cycle responds to volcanic eruptions is valuable in

  2. Does cycling effect motor coordination of the leg during running in elite triathletes?

    Science.gov (United States)

    Chapman, Andrew R; Vicenzino, Bill; Blanch, Peter; Dowlan, Steve; Hodges, Paul W

    2008-07-01

    Triathletes report incoordination when running after cycling. We investigated the influence of the transition from cycling to running on leg movement and muscle recruitment during running in elite international level triathletes. Leg movement (three-dimensional kinematics) and tibialis anterior (TA) muscle activity (surface electromyography) were compared between a control-run (no prior exercise) and a 30-min transition-run (preceded by 20 min of cycling; i.e., run versus cycle-run). The role of fatigue in motor changes was also investigated. Leg kinematics were not different between control- and transition-runs in any triathlete. Recruitment of TA was different in 5 of 14 triathletes, in whom altered TA recruitment patterns during the transition-run were more similar to recruitment patterns of TA during cycling. Changes in TA recruitment during the transition-run were not associated with altered force production of TA or other leg muscles during isometric fatigue testing, or myoelectric indicators of fatigue (median frequency, average rectified value). These findings suggest that short periods of cycling do not influence running kinematics or TA muscle activity in most elite triathletes. However, our findings are evidence that leg muscle activity during running is influenced by cycling in at least some elite triathletes despite their years of training. This influence is not related to kinematic variations and is unlikely related to fatigue but may be a direct effect of cycling on motor commands for running.

  3. Aging and emotional memory: cognitive mechanisms underlying the positivity effect.

    Science.gov (United States)

    Spaniol, Julia; Voss, Andreas; Grady, Cheryl L

    2008-12-01

    Younger adults tend to remember negative information better than positive or neutral information (negativity bias). The negativity bias is reduced in aging, with older adults occasionally exhibiting superior memory for positive, as opposed to negative or neutral, information (positivity bias). Two experiments with younger (N=24 in Experiment 1, N=25 in Experiment 2; age range: 18-35 years) and older adults (N=24 in both experiments; age range: 60-85 years) investigated the cognitive mechanisms responsible for age-related differences in recognition memory for emotional information. Results from diffusion model analyses (R. Ratcliff, 1978) indicated that the effects of valence on response bias were similar in both age groups but that Age x Valence interactions emerged in memory retrieval. Specifically, older adults experienced greater overall familiarity for positive items than younger adults. We interpret this finding in terms of an age-related increase in the accessibility of positive information in long-term memory.

  4. Aging Effect on Lanthanum Doped Ferroelectric Lead Titanate Ceramics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Ferroelectric devices are widely applied in many fields, such as energy conversion and communication. The aging effect in ferroelectric materials plays a central role in the reliability of the related equipments. But it is very difficult to understand the origin of aging effect in ferroelectrics because these materials possess different defects and exhibit various aging behavior. The reverse transition temperature in lead titanate doped with lanthanum increases during aging at ferroelectric phase was reported. It is well known that lattice defects, such as vacancies and solute atoms, are ubiquitous in crystalline solids. These point defects affect physical properties in ferroelectrics significantly. The abnormal increase of the reverse transition temperature was discussed in terms of diffusion of point defects during aging. Dielectric performance in the material after aging was measured and discussed as well.

  5. Lamb wave characterization of the effects of long-term thermal-mechanical aging on composite stiffness

    Science.gov (United States)

    Seale, M. D.; Madaras, E. I.

    1999-01-01

    Lamb waves offer a promising method of evaluating damage in composite materials. The Lamb wave velocity is directly related to the material parameters, so an effective tool exists to monitor damage in composites by measuring the velocity of these waves. The Lamb Wave Imager (LWI) uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide frequency range. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the dispersion curve. In this study, the time-of-flight as well as the elastic stiffnesses D11, D22, A44, and A55 for composite samples which have undergone combined thermal and mechanical aging are obtained. The samples examined include a baseline specimen with 0 cycles, specimens which have been aged 2350 and 3530 cycles at high strain levels, and one specimen aged 3530 cycles at low strain levels.

  6. Effect of Air Pollution on Menstrual Cycle Length-A Prognostic Factor of Women's Reproductive Health.

    Science.gov (United States)

    Merklinger-Gruchala, Anna; Jasienska, Grazyna; Kapiszewska, Maria

    2017-07-20

    Air pollution can influence women's reproductive health, specifically menstrual cycle characteristics, oocyte quality, and risk of miscarriage. The aim of the study was to assess whether air pollution can affect the length of the overall menstrual cycle and the length of its phases (follicular and luteal). Municipal ecological monitoring data was used to assess the air pollution exposure during the monitored menstrual cycle of each of 133 woman of reproductive age. Principal component analyses were used to group pollutants (PM10, SO₂, CO, and NOx) to represent a source-related mixture. PM10 and SO₂ assessed separately negatively affected the length of the luteal phase after standardization (b = -0.02; p = 0.03; b = -0.06; p = 0.02, respectively). Representing a fossil fuel combustion emission, they were also associated with luteal phase shortening (b = -0.32; p = 0.02). These pollutants did not affect the follicular phase length and overall cycle length, neither in single- nor in multi-pollutant models. CO and NOx assessed either separately or together as a traffic emission were not associated with overall cycle length or the length of cycle phases. Luteal phase shortening, a possible manifestation of luteal phase deficiency, can result from fossil fuel combustion. This suggests that air pollution may contribute to fertility problems in women.

  7. Effect of aging time and temperature on the aging behavior in Sn containing AZ91 alloy

    Science.gov (United States)

    Kim, Jeong Kyun; Oh, Seung Hyun; Kim, Kang Cheol; Kim, Won Tae; Kim, Do Hyang

    2017-02-01

    Effects of aging temperature and time on the aging behavior in AZ91 alloy and Sn containing AZ91 alloy (AZT915) have been investigated in the present study. The mode of precipitation, i.e. discontinuous and continuous precipitation in both alloys is strongly affected by the aging temperature. At low aging temperature of 403 K, only discontinuous precipitation occurs at the grain boundaries, whereas at high aging temperatures of 573 and 623 K only continuous precipitation occurs inside the grains. At intermediate temperature range (443 or 498 K) both discontinuous and continuous precipitation reactions occur. In AZT915, the Mg2Sn particles at the grain boundary effectively reduce the available nucleation sites for discontinuous β precipitates, and slow down the movement of the grain boundary, resulting in suppression of discontinuous precipitation. In addition, increased local lattice strain by the presence of Sn in the α-Mg solid solution matrix accelerates the nucleation of the continuous precipitates at the early stage of aging treatment. Therefore, significantly higher peak hardness can be obtained within a shorter aging time in AZT915.

  8. Influence of the type of working fluid in the lower cycle and superheated steam parameters in the upper cycle on effectiveness of operation of binary power plant

    Directory of Open Access Journals (Sweden)

    Stachel Aleksander A.

    2015-03-01

    Full Text Available In the paper presented have been the results of the analysis of effectiveness of operation of binary power plant consisting of combined two Clausius-Rankine cycles, namely the binary cycle with water as a working fluid in the upper cycle and organic substance as a working fluid in the lower cycle, as well as a single fluid component power plant operating also in line with the C-R cycle for superheated steam, with water as a working fluid. The influence of the parameters of superheated steam in the upper cycle has been assessed as well as the type of working fluid in the lower cycle. The results of calculations have been referred to the single-cycle classical steam power plant operating at the same parameters of superheated steam and the same mass flow rate of water circulating in both cycles. On the basis of accomplished analysis it has been shown that the binary power plant shows a greater power with respect to the reference power plant.

  9. Effects of estrogen fluctuation during the menstrual cycle on the response to stretch-shortening exercise in females.

    Science.gov (United States)

    Sipavičienė, Saulė; Daniusevičiutė, Laura; Klizienė, Irina; Kamandulis, Sigitas; Skurvydas, Albertas

    2013-01-01

    The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.7 yr) participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72 h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue) between the two menstrual cycle phases were small.

  10. Effects of Estrogen Fluctuation during the Menstrual Cycle on the Response to Stretch-Shortening Exercise in Females

    Directory of Open Access Journals (Sweden)

    Saulė Sipavičienė

    2013-01-01

    Full Text Available The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n=18; age = 20.2 ± 1.7 yr participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72 h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue between the two menstrual cycle phases were small.

  11. The Correlation of the TBC Lifetimes in Burner Cycling Test with Thermal Gradient and Furnace Isothermal Cycling Test by TGO Effects

    Science.gov (United States)

    Li, Chang-Jiu; Dong, Hui; Ding, Hang; Yang, Guan-Jun; Li, Cheng-Xin

    2017-02-01

    Two types of typical thermal cycling tests are used for the evaluation of thermal cycling lifetime of thermal barrier coatings. Those are the burner cycling test with a thermal gradient and the isothermal furnace cycling test. There are diverse explanations to test results up to now. Although certain correlations should exist between the results obtained by two types of the tests, no evident parameters in two tests were directly related, possibly due to large range of difference test conditions. In this investigation, a series of TBC samples with carefully prepared Al2O3-based TGO of different thicknesses were used for both the burner cycling and the furnace cycling tests. The relationships between thermal cycling lifetime and TGO thickness were obtained for two types of the tests. It was found that TGO thickness presents the same influence tendency despite of different types of thermal cycling test. The results reveal the existence of the critical TGO thickness by which the transition of failure mode takes place. Moreover, the values of the critical TGO thickness for two tests are comparable. The results evidently suggest that the lifetimes during different thermal cycling tests can be correlated by TGO effects on failure behavior. However, it is clear that the apparent dominant driving factors to TBC failure are different in two types of tests. Accordingly, the burner cycling test could be used for optimizing the durability of ceramic top coat by separating the effect of individual factors through test condition design, while the furnace cycling test results represent the integrated TBC durable performance of the bond coat and top ceramic coating.

  12. Antidepressant Prescription and Suicide Rates: Effect of Age and Gender

    Science.gov (United States)

    Kalmar, Sandor; Szanto, Katalin; Rihmer, Zoltan; Mazumdar, Sati; Harrison, Katrin; Mann, J. John

    2008-01-01

    To determine whether the effect of antidepressant exposure on suicide rate is modified by age and gender in Hungary, annual antidepressant prescription rates and suicide rates of about 10 million inhabitants between 1999-2005 were analyzed by age and gender groups. The suicide rate was inversely related to the increased use of antidepressants in…

  13. Boosting Early Development: The Mixed Effects of Kindergarten Enrollment Age

    Science.gov (United States)

    Zhang, Jiahui; Xin, Tao

    2012-01-01

    This study aimed to investigate the effects of kindergarten enrollment age on four-year-old Chinese children's early cognition and problem behavior using multilevel models. The sample comprised of 1,391 pre-school children (the mean age is 4.58 years old) from 74 kindergartens in six different provinces. The results demonstrated curvilinear…

  14. A Conceptual Review of Age Effect on L2 Acquisition

    Science.gov (United States)

    Sang, Yuan

    2017-01-01

    The importance of age effect on an additional language (L2) acquisition has long been recognized in the field of L2 education. Research was conducted to reveal the influence of age to the rate and ultimate attainment of L2 teaching and learning, yet controversial results were discovered. Consequently, stereotypes and misunderstanding exist among…

  15. Food Decision-Making : Effects of Weight Status and Age

    NARCIS (Netherlands)

    van Meer, Floor; Charbonnier, Lisette; Smeets, Paul A M

    2016-01-01

    Food decisions determine energy intake. Since overconsumption is the main driver of obesity, the effects of weight status on food decision-making are of increasing interest. An additional factor of interest is age, given the rise in childhood obesity, weight gain with aging, and the increased chance

  16. Effects of initial fattening age on carcass characteristics and meat ...

    African Journals Online (AJOL)

    Windows-XP

    2017-02-16

    Feb 16, 2017 ... 5Tabiat Agriculture Limited Company, Yenisehir/Bursa, Turkey. ... Yet population growth has led to increased demand for meat ..... depending on breed, castration age, gender, nutrition, and genetics, along with economic factors such as ..... Effect of breed and ageing time on meat quality and sensory ...

  17. Effect of Age and Other Factors on Maximal Heart Rate.

    Science.gov (United States)

    Londeree, Ben R.; Moeschberger, Melvin L.

    1982-01-01

    To reduce confusion regarding reported effects of age on maximal exercise heart rate, a comprehensive review of the relevant English literature was conducted. Data on maximal heart rate after exercising with a bicycle, a treadmill, and after swimming were analyzed with regard to physical fitness and to age, sex, and racial differences. (Authors/PP)

  18. Perceptions toward cycling in Zagreb area: Differences concerning age, gender and membership in the association “Trade Union of Cyclists”

    Directory of Open Access Journals (Sweden)

    Joško Sindik

    2013-12-01

    Full Text Available Bicycle riding today is a widespread form of traffic, but the conditions for cycling in Zagreb, although improved, are still not satisfactory. The aim of this study was to determine gender differences along with differences in the perceptions of members of the association of Cyclists trade union with a “typical” Zagreb cyclist, in terms of various factors relating to the problems of cycling in Zagreb. The correlation between these perceptions and the age of the participants was studied. Over 3000 members of the association as well as cyclists who are not members of the association (“typical” cyclist were interviewed using conveniently assembled questionnaire. Results show that the members of the association bicycle on average more often and for various purposes compared to typical cyclists and are more motivated for more frequent and safer cycling in urban conditions, perceive more barriers to cycling, have more accidents of various types and see disadvantages of the current solutions offered by the City of Zagreb as more serious. Both the typical cyclists and the members of the association show similar trends in average results. Gender differences indicate the trend of rarer use of bicycles for women, as compared to men, which can be influenced by perceived (uncertainty of the bicycle traffic in Zagreb. The relationship between variables related to cycling with chronological age of the participants (with only one exception was not found to be statistically significant, which is most likely due to the fact that a majority share of the participants are of a younger age. The results obtained in this study indicate a need for taking constructive social action to improve conditions for cycling in Zagreb and suburban areas.

  19. Modeling the effects of cell cycle M-phase transcriptional inhibition on circadian oscillation.

    Directory of Open Access Journals (Sweden)

    Bin Kang

    2008-03-01

    Full Text Available Circadian clocks are endogenous time-keeping systems that temporally organize biological processes. Gating of cell cycle events by a circadian clock is a universal observation that is currently considered a mechanism serving to protect DNA from diurnal exposure to ultraviolet radiation or other mutagens. In this study, we put forward another possibility: that such gating helps to insulate the circadian clock from perturbations induced by transcriptional inhibition during the M phase of the cell cycle. We introduced a periodic pulse of transcriptional inhibition into a previously published mammalian circadian model and simulated the behavior of the modified model under both constant darkness and light-dark cycle conditions. The simulation results under constant darkness indicated that periodic transcriptional inhibition could entrain/lock the circadian clock just as a light-dark cycle does. At equilibrium states, a transcriptional inhibition pulse of certain periods was always locked close to certain circadian phases where inhibition on Per and Bmal1 mRNA synthesis was most balanced. In a light-dark cycle condition, inhibitions imposed at different parts of a circadian period induced different degrees of perturbation to the circadian clock. When imposed at the middle- or late-night phase, the transcriptional inhibition cycle induced the least perturbations to the circadian clock. The late-night time window of least perturbation overlapped with the experimentally observed time window, where mitosis is most frequent. This supports our hypothesis that the circadian clock gates the cell cycle M phase to certain circadian phases to minimize perturbations induced by the latter. This study reveals the hidden effects of the cell division cycle on the circadian clock and, together with the current picture of genome stability maintenance by circadian gating of cell cycle, provides a more comprehensive understanding of the phenomenon of circading gating of

  20. Modeling the effects of cell cycle M-phase transcriptional inhibition on circadian oscillation.

    Science.gov (United States)

    Kang, Bin; Li, Yuan-Yuan; Chang, Xiao; Liu, Lei; Li, Yi-Xue

    2008-03-28

    Circadian clocks are endogenous time-keeping systems that temporally organize biological processes. Gating of cell cycle events by a circadian clock is a universal observation that is currently considered a mechanism serving to protect DNA from diurnal exposure to ultraviolet radiation or other mutagens. In this study, we put forward another possibility: that such gating helps to insulate the circadian clock from perturbations induced by transcriptional inhibition during the M phase of the cell cycle. We introduced a periodic pulse of transcriptional inhibition into a previously published mammalian circadian model and simulated the behavior of the modified model under both constant darkness and light-dark cycle conditions. The simulation results under constant darkness indicated that periodic transcriptional inhibition could entrain/lock the circadian clock just as a light-dark cycle does. At equilibrium states, a transcriptional inhibition pulse of certain periods was always locked close to certain circadian phases where inhibition on Per and Bmal1 mRNA synthesis was most balanced. In a light-dark cycle condition, inhibitions imposed at different parts of a circadian period induced different degrees of perturbation to the circadian clock. When imposed at the middle- or late-night phase, the transcriptional inhibition cycle induced the least perturbations to the circadian clock. The late-night time window of least perturbation overlapped with the experimentally observed time window, where mitosis is most frequent. This supports our hypothesis that the circadian clock gates the cell cycle M phase to certain circadian phases to minimize perturbations induced by the latter. This study reveals the hidden effects of the cell division cycle on the circadian clock and, together with the current picture of genome stability maintenance by circadian gating of cell cycle, provides a more comprehensive understanding of the phenomenon of circading gating of cell cycle.

  1. Teaching STEM Effectively with the Learning Cycle Approach

    Directory of Open Access Journals (Sweden)

    Pradeep M. Dass

    2015-01-01

    Full Text Available The main challenges for teachers with regard to STEM-oriented instruction are: 1 How to integrate science, technology, engineering and mathematics in such a way that students see the interconnectedness and interdependence between these disciplines; and 2 How to help students realize that solutions to real world problems or issues involve the combined use of knowledge, processes and practices from all of these disciplines. In order to teach STEM effectively, these two challenges must be met, but how? Teachers need pedagogical approaches or models that can address these challenges effectively. Given that the STEM definition adopted by IPST includes "the application of knowledge to real-life problem solving", it follows that effective STEM-oriented instruction must involve a pedagogy that is centered around real-life issues, concerns, problems or questions and offers students the opportunity to employ two or more of the STEM disciplines in an integrated manner to address the questions.

  2. Short versus Long Gonadotropin-Releasing Hormone Analogue Suppression Protocols in IVF/ICSI Cycles in Patients of Various Age Ranges.

    Directory of Open Access Journals (Sweden)

    Jianping Ou

    Full Text Available To compare the two GnRH-a protocols (long GnRH-a protocol and short GnRH-a protocol for ovarian stimulation in IVF/ICSI cycles in patients of various age ranges.A total of 5662 IVF-ET/ICSI cycles from 2010 to 2013 were retrospectively identified. The cycles were divided into two groups: a long protocol group and short protocol group. In each group, the patients were divided into four age ranges: 40 years. The duration of stimulation, total dose of Gn, implantation rate and pregnancy rate were compared.The total dose of Gn was significantly higher, and the duration of stimulation was significantly longer, in the long protocol group than in the short protocol group for all age ranges (P<0.05. If the patients were of the same age range, the number of oocytes retrieved, MII oocytes, and high-quality embryos in the long protocol group were all significantly greater than those in the short protocol group (P<0.05. In the long protocol group, the clinical pregnancy rates of the four age ranges were 52.76%, 44.33%, 36.15% and 13.33%, respectively, which were significantly higher than those in the short protocol group (33.33%, 24.58%, 22.49% and 8.72%, respectively; P<0.05. The same trend was also found in the implantation rates of the four age ranges. As the age increased, the clinical pregnancy and implantation rates, as well as the number of oocytes retrieved, MII oocytes, and high-quality embryos, of the long protocol group significantly decreased (P<0.05.Our study demonstrated that regardless of patient age, the long protocol was superior to the short protocol in terms of the number of retrieved oocytes, as well as the implantation and pregnancy rates.

  3. Effects of aging in electric field on 2024 alloy

    Institute of Scientific and Technical Information of China (English)

    王秀芳; 孙东立; 武高辉; 王美玲

    2002-01-01

    The effect of heat treatment in an electric field on micro-plastic deformation characteristics of 2024 Al alloy was investigated.The mechanism of aging in an electric field affecting the micro-plastic deformation behavior was preliminarily discussed.The results show that the resistance to micro-plastic deformation of the alloy can be greatly increased by aging in an electric field.Aging temperature,aging time and electric field strength are selected by adopting the orthogonal design method and the optimum technological parameters are obtained.

  4. Anti-aging effects of vitamin C on human pluripotent stem cell-derived cardiomyocytes.

    Science.gov (United States)

    Kim, Yoon Young; Ku, Seung-Yup; Huh, Yul; Liu, Hung-Ching; Kim, Seok Hyun; Choi, Young Min; Moon, Shin Yong

    2013-10-01

    Human pluripotent stem cells (hPSCs) have arisen as a source of cells for biomedical research due to their developmental potential. Stem cells possess the promise of providing clinicians with novel treatments for disease as well as allowing researchers to generate human-specific cellular metabolism models. Aging is a natural process of living organisms, yet aging in human heart cells is difficult to study due to the ethical considerations regarding human experimentation as well as a current lack of alternative experimental models. hPSC-derived cardiomyocytes (CMs) bear a resemblance to human cardiac cells and thus hPSC-derived CMs are considered to be a viable alternative model to study human heart cell aging. In this study, we used hPSC-derived CMs as an in vitro aging model. We generated cardiomyocytes from hPSCs and demonstrated the process of aging in both human embryonic stem cell (hESC)- and induced pluripotent stem cell (hiPSC)-derived CMs. Aging in hESC-derived CMs correlated with reduced membrane potential in mitochondria, the accumulation of lipofuscin, a slower beating pattern, and the downregulation of human telomerase RNA (hTR) and cell cycle regulating genes. Interestingly, the expression of hTR in hiPSC-derived CMs was not significantly downregulated, unlike in hESC-derived CMs. In order to delay aging, vitamin C was added to the cultured CMs. When cells were treated with 100 μM of vitamin C for 48 h, anti-aging effects, specifically on the expression of telomere-related genes and their functionality in aging cells, were observed. Taken together, these results suggest that hPSC-derived CMs can be used as a unique human cardiomyocyte aging model in vitro and that vitamin C shows anti-aging effects in this model.

  5. Effect of Estradiol Prescribed during Luteal Phase of Art Cycles and Pregnancy Outcome

    OpenAIRE

    2007-01-01

    Introduction: Implantation is one of the most important steps in ART cycles and it depends upon embryo and endometrial reception. Different protocols have been suggested for getting better endometrium. It seems estrogen increases the endometrial reception and pregnancy rate by inducing changes in the hormonal status. The aim of this study was to evaluate the effect of estradiol(E2) on luteal phase support and pregnancy rate in ART cycles Methods: This prospective randomized study was done in ...

  6. Deformation Cycling of a Ti - Ni Alloy with Superelasticity Effect Applied in Cardiology

    Science.gov (United States)

    Kaputkin, D. E.; Morozova, T. V.

    2014-07-01

    The study concerns the effect of the conditions and of the force of loading experienced by an implanted device from a Ti - Ni alloy during its transfer to the working zone, for example, in endoscopic implantation into the coronary sinus of the greater vena cava of heart. It is shown that preliminary deformation cycling (10 - 15 cycles) stabilizes the set of mechanical properties of the alloy.

  7. Cure Cycle Effect on High-Temperature Polymer Composite Structures Molded by VARTM

    OpenAIRE

    Ahmed Khattab

    2013-01-01

    This paper presents an analytical and experimental investigation of cure cycle effect on carbon-fiber reinforced high-temperature polymer composite structures molded by vacuum assisted resin transfer molding (VARTM). The molded composite structure consists of AS4-8 harness carbon-fiber fabrics and a high-temperature polymer (Cycom 5250-4-RTM). Thermal and resin cure analysis is performed to model the cure cycle of the VARTM process. The temperature and cure variations with time are determined...

  8. Effects of early pregnancy loss on hormone levels in the subsequent menstrual cycle

    OpenAIRE

    2010-01-01

    Previous studies of hormone patterns after clinical miscarriage suggest reduced pituitary function. Hormonal effects of very early pregnancy loss (before six weeks gestation) have not been described. We used within-woman differences between menstrual cycles in urinary hormone measurements from women in the North Carolina Early Pregnancy Study to describe hormonal changes after very early pregnancy loss (n=28 early losses; 80 non-conception comparison cycles). We found lower pre-ovulatory lute...

  9. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test

    OpenAIRE

    Hintzy, Frédérique; Grappe, Frédéric; Belli, Alain

    2016-01-01

    Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis), in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer...

  10. The effect of foot orthoses and in-shoe wedges during cycling: a systematic review

    OpenAIRE

    Yeo, Boon K; Bonanno, Daniel R

    2014-01-01

    Background The use of foot orthoses and in-shoe wedges in cycling are largely based on theoretical benefits and anecdotal evidence. This review aimed to systematically collect all published research on this topic, critically evaluate the methods and summarise the findings. Methods Study inclusion criteria were: all empirical studies that evaluated the effects of foot orthoses or in-shoe wedges on cycling; outcome measures that investigated physiological parameters, kinematics and kinetics of ...

  11. A COMPARISON OF THE EFFECTS OF FATIGUE ON SUBJECTIVE AND OBJECTIVE ASSESSMENT OF SITUATION AWARENESS IN CYCLING

    Directory of Open Access Journals (Sweden)

    Wade L. Knez

    2006-03-01

    Full Text Available Maximal effort on a 30 km Time Trial (TT30 was examined to assess whether it would elicit changes in objective and subjective tests of the participants' perception of the environment and their ability to anticipate future occurrences (situation awareness; SA and to determine the effect of post-exercise recovery on SA. Nine experienced (5.22 ± 2.77 years road cyclists had their objective and subjective levels of SA assessed prior to and at the completion of two TT30. The participants' results were compared to measurements of maximal oxygen uptake (VO2max, peak power output (PPO, age and years of competitive cycle racing experience. Fatigue resulting from maximal effort on a TT30 produced significant changes in both the objective and subjective test of SA. Effect sizes of 0.93 and 0.99 indicated that the first and second TT30 were likely or almost certain to have a beneficial effect on the objective assessment of SA. However, the effect sizes of 0.97 and 0.95 relating to the subjective assessment of cognitive performance on the first and second TT30 showed that it was very likely the participants' had an increased difficulty in maintaining SA. A recovery period of up to three minutes post TT30 had no effect on SA. Changes in SA had no relationship with measurements of VO2max, peak power output (PPO, age and years of competitive cycle racing experience. The findings suggest that within a laboratory environment, participants consistently underestimate their ability to make accurate assessments of their cycling environment compared to objective measures of their SA

  12. Age, education, and sex effects on adult moral reasoning.

    Science.gov (United States)

    White, C B

    1988-01-01

    The role of age and education in adult moral reasoning was examined utilizing Kohlberg's cognitive-developmental stage theory of moral development and the most recent Standard Scoring System for assessing moral judgments. Individual interviews utilizing standard Kohlberg moral dilemmas were conducted with 195 adults ranging in age from nineteen to eight-two years and in years of education from three to twenty-five years. Results indicated no overall significant effect for age of reasoner, no significant effect for sex, and a significant effect for education (p less than .01). However, the effect of age was significant in the group with eighteen or more years of education, but not in the group with less than eighteen years of education.

  13. Effect of ageing on fatigue properties of asphalt

    Institute of Scientific and Technical Information of China (English)

    王佶; 庞凌; 吴少鹏; 刘全涛; 陈筝

    2008-01-01

    The fatigue properties of asphalts were investigated after various laboratory simulation ageing tests and outdoor natural exposure ultraviolet radiation ageing,by dynamic shear rheometer(DSR) time sweep fatigue test in constant strain model and a new type of specimen which was introduced to avoid the problem of adhesion failure between rotor and asphalt binder.The results show that outdoor natural exposure ageing(NEA) causes the decrease of retained fatigue life distinctly,and photodegradation caused by outdoor NEA of 1 250 μm thin films asphalt for three months,is found to be severer than pressure ageing vessel(PAV) with respects to retained fatigue life.The effect of photodegradation increases as the time of outdoor NEA increases.DSR time sweep fatigue test in constant strain indicates that the aged styrene-butadiene-styrene(SBS) modified asphalt still displays better fatigue properties than the corresponding base asphalt after ageing.

  14. Age effects in the human middle ear: Wideband acoustical measures

    Science.gov (United States)

    Feeney, M. Patrick; Sanford, Chris A.

    2004-12-01

    Studies that have examined age effects in the human middle ear using either admittance measures at 220 or 660 Hz or multifrequency tympanometry from 200 to 2000 Hz have had conflicting results. Several studies have suggested an increase in admittance with age, while several others have suggested a decrease in admittance with age. A third group of studies found no significant age effect. This study examined 226 Hz tympanometry and wideband energy reflectance and impedance at ambient pressure in a group of 40 young adults and a group of 30 adults with age >=60 years. The groups did not differ in admittance measures of the middle ear at 226 Hz. However, significant age effects were found in wideband energy reflectance and impedance. In particular, in older adults there was a comparative decrease in reflectance from 800 to 2000 Hz but an increase near 4000 Hz. The results suggest a decrease in middle-ear stiffness with age. The findings of this study hold relevance for understanding the aging process in the auditory system, for the establishment of normative data for wideband energy reflectance, for the possibility of a conductive component to presbycusis, and for the interpretation of otoacoustic emission measurements. .

  15. Age-related cognitive decline during normal aging: the complex effect of education.

    Science.gov (United States)

    Ardila, A; Ostrosky-Solis, F; Rosselli, M; Gómez, C

    2000-08-01

    The purpose of this study was to further analyze the effects of education on cognitive decline during normal aging. An 806-subject sample was taken from five different Mexican regions. Participants ranged in age from 16 to 85 years. Subjects were grouped into four educational levels: illiterate, 1-4, 5-9, and 10 or more years of education, and four age ranges: 16-30, 31-50, 51-65, and 66-85 years. A brief neuropsychological test battery (NEUROPSI), standardized and normalized in Spanish, was administered. The NEUROPSI test battery includes assessment of orientation, attention, memory, language, visuoperceptual abilities, motor skills, and executive functions. In general, test scores were strongly associated with level of educational, and differences among age groups were smaller than differences among education groups. However, there was an interaction between age and education such as that among illiterate individuals scores of participants 31-50 years old were higher than scores of participants 16-30 years old for over 50% of the tests. Different patterns of interaction among educational groups were distinguished. It was concluded that: (a) The course of life-span changes in cognition are affected by education. Among individuals with a low level of education, best neuropsychological test performance is observed at an older age than among higher-educated subjects; and (b) there is not a single relationship between age-related cognitive decline and education, but different patterns may be found, depending upon the specific cognitive domain.

  16. Fracturing and Damage to Sandstone Under Coupling Effects of Chemical Corrosion and Freeze-Thaw Cycles

    Science.gov (United States)

    Han, Tielin; Shi, Junping; Cao, Xiaoshan

    2016-11-01

    Rapid freeze-thaw (FT) cycles were adopted to explore the damage deterioration mechanism and mechanical properties of sandstone specimens under the coupling effects of different chemical solutions and FT cycles. The variation regularities of the FT cycles and physical and mechanical properties of sandstone specimens immersed in different chemical solutions were analyzed by using sandstone sampled from a Chinese riverbank slope. The damage variable based on porosity variation was used in the quantitative analysis of the damage to the sandstone under the coupling effects of chemical corrosion and FT cycles. Experimental results showed that the sandstone specimens weakened substantially under those effects. Their fracture toughness K IC, splitting tensile strength, and compressive strength showed a similar deteriorating trend with various numbers of FT cycles. However, a difference exists in the deterioration degree of their mechanical parameters, i.e., the deterioration degree of their fracture toughness K IC is the greatest followed by that of splitting tensile strength, and that of compressive strength is relatively small. Strong acid solutions may aggravate the deterioration of FT damage in sandstones, but at the early stage of the experiment, strong alkaline solutions inhibited sandstone damage deterioration. However, the inhibiting effect disappeared when the number of FT cycles exceeded 25. The different chemical solutions had a different effect on the FT damage degree of the sandstone specimens; for example, SO4 2- ions had a greater effect on FT damage than did HCO3 - ions. Water-chemical solutions and FT cycles promote each other in deteriorating rocks and simultaneously affect the damage deterioration degree of sandstones.

  17. Effect of age on body composition in healthy Beijing women

    Institute of Scientific and Technical Information of China (English)

    Chen Rong; Lin Shou-qing; Lin Xia; Chen Yan; Yang Qiu-hong; Zhou Yong; Zhang Ying

    2011-01-01

    Objective:To explore the effect of age on body composition in healthy Beijing women.Methods:We measured body composition with dual-energy X-ray (GE Lunar Prodigy) in 316 healthy Beijing females aged 20 to 74 years (5-7 women per age).Parameters provided by the software were as following:total body bone mineral content (BMC),lean mass (LM),fat mass and fat mass percentage (FM%).Local regions measured included arm,leg,trunk,android region and gynoid region.Body mass index (BMI),fat mass index (FMI),free fat mass index (FFMI) and A/G were calculated.Volunteers were assigned to 6 groups according to age by every ten years a group.Results..BMC peaked during the 4th decade,LM peaked during the 5th decade,with a decline of 18.1% and 5.2% respectively at age 74 years.Total body fat mass and FM% showed a general increase with aging throughout the studied age range.Total body fat mass increased from (16±5) kg at age 20-29 years to (24±6)kg at age 70-74years,while FM% increased from 31.3% to 39.5%.All local region FM% increased with aging at different extents.Android region FM% showed the largest raise extent (32.2%).BMI increased gradually from 21.1 kg/m2 at age 20-29 years to 26.1 kg/m2 at age 70-74 years.FMI changed more obviously than FFMI.A/G increased from 0.85 at age 20-29 years to 1.02 at age 70-74 years.Different menstrual status in women of 40-59 years had obvious effect on A/G and BMC (P<0.05),while it had no significant effect on BMI,body weight and waist circumference (P>0.05).Conclusion:Aging has a great effect on body composition distribution in healthy Beijing women.

  18. Effective Anti-aging Strategies in an Era of Super-aging.

    Science.gov (United States)

    Park, Saerom; Yang, Min-Ji; Ha, So-Nyeong; Lee, Jeong-Sang

    2014-12-01

    The societies of the world in the 21(st) century have faced challenges arising from an aging population as the fertility rate has dropped dramatically and medical advances have extended the average human life span. The elderly aged 65 years or older make up at least 20% of the population in Korea, making the country a super-aging society as defined by the United Nations. The number of elderly women is higher than that of elderly men and women live longer than men. Based on the analysis of recent trends in previous studies, this study aimed to suggest practical strategies to utilize isoflavones, substances chemically similar to the female hormone estrogen, and to search for effective anti-aging strategies using this substance for women to be prepared to reach the elderly stage in good health.

  19. Cell cycle and aging, morphogenesis, and response to stimuli genes are individualized biomarkers of glioblastoma progression and survival

    Directory of Open Access Journals (Sweden)

    Southey Bruce R

    2011-06-01

    . Biological processes associated glioblastoma survival included morphogenesis, cell cycle, aging, response to stimuli, and programmed cell death. Conclusions Known biomarkers of glioblastoma survival were confirmed, and new general and clinical-dependent gene profiles were uncovered. The comparison of biomarkers across glioblastoma phases and functional analyses offered insights into the role of genes. These findings support the development of more accurate and personalized prognostic tools and gene-based therapies that improve the survival and quality of life of individuals afflicted by glioblastoma multiforme.

  20. Effects of Stratospheric Ozone Depletion, Solar UV Radiation, and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment...

  1. Effects of Stratospheric Ozone Depletion, Solar UV Radiation, and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment...

  2. Menstrual cycle effects on cortisol responsivity and emotional retrieval following a psychosocial stressor.

    Science.gov (United States)

    Maki, Pauline M; Mordecai, Kristen L; Rubin, Leah H; Sundermann, Erin; Savarese, Antonia; Eatough, Erin; Drogos, Lauren

    2015-08-01

    This article is part of a Special Issue "Estradiol and cognition". Laboratory-induced stress produces elevations in cortisol and deficits in memory, especially when stress is induced immediately before retrieval of emotionally valent stimuli. Sex and sex steroids appear to influence these stress-induced outcomes, though no study has directly compared the effects of laboratory-induced stress on cortisol and emotional retrieval across the menstrual cycle. We examined the effect of psychosocial stress on cortisol responsivity and emotional retrieval in women tested during either the follicular phase (low estradiol and progesterone) or the luteal phase (higher estradiol and progesterone). Forty women (50% White; age 18-40 years) participated in the study; 20 completed the task during the luteal phase and 20 during the follicular phase. Psychosocial stress was induced with the Trier Social Stress Test (TSST). On the day before the TSST, participants learned two lists of word pairs to 100% criterion. The next day, participants recalled one list after the control condition and the other after the TSST. Women in the follicular phase, but not the luteal phase, demonstrated a significant cortisol response to the TSST. There was a stress-induced decrease in emotional retrieval following the TSST, but this effect was not modified by menstrual phase. However, regression and correlational analyses showed that individual differences in stress-induced cortisol levels were associated with impaired emotional retrieval in the follicular phase only. The present findings indicate that cortisol responsivity and the impairing effects of cortisol on emotional memory are lower when levels of estradiol and progesterone are high compared to when levels are low.

  3. Age-related differences in arithmetic strategy sequential effects.

    Science.gov (United States)

    Lemaire, Patrick

    2016-03-01

    In this article, I review a series of new findings concerning how age-related changes in strategic variations are modulated by sequential effects. Sequential effects refer to how strategy selection and strategy execution on current problems are influenced by which strategy is used on immediately preceding problems. Two sequential effects during strategy selection (i.e., strategy revisions and strategy perseverations) and during strategy execution (i.e., strategy switch costs and modulations of poorer strategy effects) are presented. I also discuss how these effects change with age during adulthood. These phenomena are important, as they shed light on arithmetic processes and how these processes change with age during adulthood. In particular, they speak to the role of executive control while participants select and execute arithmetic strategies. Finally, I discuss the implications of sequential effects for theories of strategies and of arithmetic.

  4. EFFECTS OF 5E LEARNING CYCLE ON STUDENTS ACHIEVEMENT IN BIOLOGY AND CHEMISTRY

    Directory of Open Access Journals (Sweden)

    Patrick Osawaru Ajaja,

    2012-01-01

    Full Text Available The major purpose of this study was to determine the effects of learning cycle as an instructional strategy on biology andchemistry students achievement. To guide this study, six research hypotheses were stated and tested at 0.05 level ofsignificance. The design of this study was 2x2x3x6 Pre-test Post-test non-equivalent control group quasi experimental design.These included two instructional groups (experimental and control groups, sex (male and female, repeated testing (Pre,Post and follow-up tests, and six weeks of experience. The samples of the study included six senior secondary schools, 112science students, and 12 biology and chemistry teachers. The instruments used for this study were: teacher’s questionnaireon knowledge and use of learning cycle (KULC; and Biology and Chemistry Achievement Test (BCAT. The data collected wereanalyzed with simple percentage, Analysis of Covariance (ANCOVA and student t-test statistics. The major findings of thestudy included that only 30.43% and 26.31% of biology and chemistry teachers have the knowledge that learning cycle is aninstructional method; all the biology and chemistry teachers sampled have never used learning cycle as an instructionalmethod; learning cycle had a significant effect on students achievement in biology and chemistry; students taught withlearning cycle significantly achieved better in biology/chemistry Post-test than those taught with lecture method; the posttestscores of students in the learning cycle group increased over the period of experience; non-significant difference in Posttestscores between males and females taught with learning cycle; non-significant interaction effect between method andsex on achievement; and a significant higher retention of biology and chemistry knowledge by students taught with learningcycle than those taught with lecture method. It was concluded that the method seems an appropriate instructional modelthat could be used to solve the problems of

  5. Nitrogen cycling in heathland ecosystems and effects of climate change

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen

    decomposition for both species. In warmed plots an early senescence was observed with effects on green Deschampsia biomass, on Deschampsia root nitrogen concentration and on acquisition of 15N from glycine. In this thesis, experiments using the stable isotopes 15N and 13C as tracers of ammonium and amino acid...... of climate change treatment. Additionally, top soil net mineralization, immobilization and leaf litter decomposition was investigated through the winter half year separately below Calluna and Deschampsia plants, and acquisition of organic nitrogen in plants and soil microorganisms was assessed. After one...

  6. Effect of microstructure refinement on low cycle fatigue behavior of Alloy 718

    Directory of Open Access Journals (Sweden)

    Mukhtarov Shamil

    2014-01-01

    Full Text Available Microstructure refinement down to d ∼ 0.1–1 μm is known to enhance processing properties of hard-to-deform materials and particularly can be used for facilitating superplastic forming or roll-forming. However refined microstructure can compromise service properties, particularly fatigue properties. In the present work, the fatigue behavior of the fine-grained Alloy 718 has been investigated. A number of fine-grained conditions with a grain size ∼0.1–1 μm were produced using multiple forging with a graduate decrease of the forging temperature. Part of the forged fine-grained conditions was also subjected to conventional solution annealing and ageing. In this case a small grain size was controlled by precipitates of the δ phase located on grain boundaries. Low cycle fatigue tests of the fine-grained conditions were carried out at room and elevated temperatures. The obtained properties are compared with those of the Alloy 718 in the coarse-grained conditions. The effect of the grain size on the fatigue strength of the fine-grained Alloy 718 is discussed in terms of the microstructure evolution and fracture mode.

  7. Market disruption, cascading effects, and economic recovery:a life-cycle hypothesis model.

    Energy Technology Data Exchange (ETDEWEB)

    Sprigg, James A.

    2004-11-01

    This paper builds upon previous work [Sprigg and Ehlen, 2004] by introducing a bond market into a model of production and employment. The previous paper described an economy in which households choose whether to enter the labor and product markets based on wages and prices. Firms experiment with prices and employment levels to maximize their profits. We developed agent-based simulations using Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate that multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment, but also suffer from market noise stemming from consumer churn. In this paper we introduce a bond market as a mechanism for household savings. We simulate an economy of continuous overlapping generations in which each household grows older in the course of the simulation and continually revises its target level of savings according to a life-cycle hypothesis. Households can seek employment, earn income, purchase goods, and contribute to savings until they reach the mandatory retirement age; upon retirement households must draw from savings in order to purchase goods. This paper demonstrates the simultaneous convergence of product, labor, and savings markets to their calculated equilibria, and simulates how a disruption to a productive sector will create cascading effects in all markets. Subsequent work will use similar models to simulate how disruptions, such as terrorist attacks, would interplay with consumer confidence to affect financial markets and the broader economy.

  8. Effect of apple production base on regional water cycle in Weibei upland of the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Weibei upland, located in southern part of the Loess Plateau, is a commercial apple production base in China. The enlargement of apple-planting area has a great impact on the regional water cycle. The effects of different land use on hydrological parameters are compared and studied in this paper. The main results are as follows: (1) The initial and steady infiltration rates in apple orchard are higher than those in other land use types such as grassland, idle land and farmland. Their initial rates of infiltration are 0.823 cm/min, 0.215 cm/min, 0.534 cm/min and 0.586 cm/min in apple orchard, grassland, idle land and farmland respectively. Their steady infiltration rates are 0.45 cm/min, 0.038 cm/min, 0.191 cm/min and 0.155 cm/min respectively. (2) There is no runoff generated in plot of apple orchard in all 8 storm events in observed natural rainfalls, while runoff is generated in winter wheat plot, com plot and alfalfa plot with runoff coefficients of 2.39%, 1.58% and 0.31% respectively. (3) The transpiration of apple trees is strong and thus soil moisture is gradually depleted. The average soil water contents in 3-9 m soil profile in Changwu plots with apple trees of 14 and 32 years in age are 11.77% and 11.59% and in Luochuan plots with those of 15 and 28 years in age are 11.7% and 11.59% respectively, which are nearly 9.0% of wilting moisture of Changwu soil and 8.6% of wilting moisture of Luochuan soil. The pathway of rainfall percolating to groundwater is hindered by dry soil profile.

  9. Effect of thermal cycling on whisker-reinforced dental resin composites.

    Science.gov (United States)

    Xu, Hockin H K; Eichmiller, Frederick C; Smith, Douglas T; Schumacher, Gary E; Giuseppetti, Anthony A; Antonucci, Joseph M

    2002-09-01

    The mechanical properties of dental resin composites need to be improved in order to extend their use to high stress-bearing applications such as crown and bridge restorations. Recent studies used single crystal ceramic whiskers to reinforce dental composites. The aim of this study was to investigate the effects of thermal cycling on whisker-reinforced composites. It was hypothesized that the whisker composites would not show a reduction in mechanical properties or the breakdown of whisker-resin interface after thermal cycling. Silicon carbide whiskers were mixed with silica particles, thermally fused, then silanized and incorporated into resin to make flexural specimens. The filler mass fraction ranged from 0% to 70%. The specimens were thermal cycled in 5 degrees C and 60 degrees C water baths, and then fractured in three-point bending to measure strength. Nano-indentation was used to measure modulus and hardness. No significant loss in composite strength, modulus and hardness was found after 10(5) thermal cycles (family confidence coefficient=0.95; Tukey's multiple comparison test). The strength of whisker composite increased with filler level up to 60%, then plateaued when filler level was further increased to 70%; the modulus and hardness increased monotonically with filler level. The strength and modulus of whisker composite at 70% filler level were significantly higher than the non-whisker controls both before and after thermal cycling. SEM revealed no separation at the whisker-matrix interfaces, and observed resin remnants on the pulled-out whiskers, indicating strong whisker-resin bonding even after 10(5) thermal cycles. In conclusion, novel dental resin composites containing silica-fused whiskers possessed superior strength and modulus compared to non-whisker composites both before and after thermal cycling. The whisker-resin bonding appeared to be resistant to thermal cycling in water, so that no loss in composite strength or stiffness occurred after

  10. Nitrogen cycling in heathland ecosystems and effects of climate change

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen

    heath types. At both heaths, plants preferred the inorganic ammonium, yet all nitrogen forms were acquired by both plants and soil microorganisms. At the temperate heath, soil microorganisms acquired the 15N 13C labeled amino acids (glycine, glutamic acid and phenylalanine) as intact compounds, and both...... decomposition for both species. In warmed plots an early senescence was observed with effects on green Deschampsia biomass, on Deschampsia root nitrogen concentration and on acquisition of 15N from glycine. In this thesis, experiments using the stable isotopes 15N and 13C as tracers of ammonium and amino acid...... dominant plant species showed indications of phenylalanine acquisition as intact compounds. The thesis consists of an introduction collecting the most important findings from the four manuscripts....

  11. Effectiveness and implementation of interventions to increase commuter cycling to school

    DEFF Research Database (Denmark)

    Østergaard, Lars; Støckel, Jan Toftegaard; Andersen, Lars Bo

    2015-01-01

    on cycling to school. METHODS: Interventions at public schools in three different regions in Denmark were based on planned infrastructural changes near schools (e.g. road surface and traffic regulation) and school-motivation for promoting commuter cycling. Participants were pupils from control schools (n......BACKGROUND: Active transportation to school has been positively associated with various health parameters whereas only sparse evidence exists on risk of injury while commuting to school. This study investigated the overall effectiveness of cycling promotion combined with structural changes...... = 12) or intervention schools (n = 13). All children (n = 2415) from the 4(th) and 5(th) grade were measured at baseline during spring 2010 and at follow-up one year later. RESULTS: No significant differences in commuter cycling were detected in the adjusted analyses comparing the intervention...

  12. Effect of polymerization cycles on flexural strengths and microhardness of different denture base materials.

    Science.gov (United States)

    Gungor, Hasan; Gundogdu, Mustafa; Alkurt, Murat; Yesil Duymus, Zeynep

    2017-01-13

    The purpose of this study was to evaluate the effect of different polymerization cycles on the flexural strengths and microhardness of two denture base materials (Meliodent and Paladent). Heat-polymerized acrylic resin specimens (65.0 mm long×10.0 mm wide×2.5 mm in height) were prepared using different short and long polymerization cycles. After the specimens had been polymerized, they were stored in distilled water at 37±1°C for 24 h. Flexural strength test was performed at a cross-head speed of 5 mm/min and Vickers microhardness was measured. Data were analyzed with a 1-way analysis of variance followed by Tukey test, and Student t-test (α=0.05). The flexural strengths and microhardness were significantly different between Meliodent and Paladent (pmicrohardness (p<0.05). Polymerization with G cycle may be suggested for Meliodent and H cycle may be suggested for Paladent.

  13. Effects of preferred and nonpreferred music on continuous cycling exercise performance.

    Science.gov (United States)

    Nakamura, Priscila M; Pereira, Gleber; Papini, Camila B; Nakamura, Fábio Y; Kokubun, Eduardo

    2010-02-01

    The aim of this study was to investigate the effects of preferred and nonpreferred music on exercise distance, Heart Rate (HR), and Rating of Perceived Exertion (RPE) during continuous cycling exercise performed at high intensity. Fifteen participants performed five test sessions. During two sessions, they cycled with fixed workload on ergometer to determine the Critical Power (CP) intensity. Then, they performed three more sessions cycling at CP intensity: listening to Preferred Music, listening to Nonpreferred Music, and No Music. The HR responses in the exercise sessions did not differ among all conditions. However, the RPE was higher for Nonpreferred Music than in the other conditions. The performance under Preferred Music (9.8 +/- 4.6 km) was greater than under Nonpreferred Music (7.1 +/- 3.5 km) conditions. Therefore, listening to Preferred Music during continuous cycling exercise at high intensity can increase the exercise distance, and individuals listening to Nonpreferred Music can perceive more discomfort caused by the exercise.

  14. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    DEFF Research Database (Denmark)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate...... extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective...... which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence...

  15. Examining Relative Age Effects in Fundamental Skill Proficiency in British Children Aged 6-11 Years.

    Science.gov (United States)

    Birch, Samantha; Cummings, Laura; Oxford, Samuel W; Duncan, Michael J

    2016-10-01

    Birch, S, Cummings, L, Oxford, SW, and Duncan, MJ. Examining relative age effects in fundamental skill proficiency in British children aged 6-11 years. J Strength Cond Res 30(10): 2809-2815, 2016-The relative age effect (RAE) suggests that there is a clustering of birth dates just after the cutoff used for sports selection in age-grouped sports and that in such circumstances, relatively older sportspeople may enjoy maturational and physical advantages over their younger peers. Few studies have examined this issue in nonselective groups of children, and none have examined whether there is evidence of any RAE in skill performance. The aim of this study was to assess whether there were differences in fundamental movement skill (FMS) proficiency within children placed in age groups according to the school year. Six FMS (sprint, side gallop, balance, jump, catch, and throw) were assessed in 539 school children (258 boys and 281 girls) aged 6-11 years (mean age ± SD = 7.7 ± 1.7 years). We examined differences in these FMS between gender groups and children born in different quarters of the year after controlling for age and body mass index (BMI). For balance, chronological age was significant as a covariate (p = 0.0001) with increases in age associated with increases in balance. Boys had significantly higher sprint mastery compared with girls (p = 0.012), and increased BMI was associated with poorer sprint mastery (p = 0.001). Boys had higher catching mastery than girls (p = 0.003), and children born in Q1 had significantly greater catching mastery than those born in Q2 (p = 0.015), Q3 (p = 0.019), and Q4 (p = 0.01). Results for throwing mastery also indicated higher mastery in boys compared with girls (p = 0.013) and that children born in Q1 had higher throwing proficiency than those born in Q4 (p = 0.038). These results are important if coaches are basing sport selection on measures of skilled performance, particularly in object-control skills. Categorizing children

  16. Thermal Cycling Effects on the Thermoelectric Properties of n-Type In, Ce based Skutterudite Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Krishnendu; Subramanian, Mas A.; Good, Morris S.; Roberts, Kamandi C.; Hendricks, Terry J.

    2012-06-14

    N-type In-filled CoSb3 are known skutterudite compounds that have shown promising thermoelectric (TE) properties resulting in high dimensionless figure of merit values at elevated temperatures. Their use in various waste heat recovery applications will require that they survive and operate after exposure to harsh thermal cycling environments. This research focused on uncovering the thermal cycling effects on thermoelectric properties of n-type In0.2Co4Sb12 and In0.2Ce0.15Co4Sb12 skutterudite compositions as well as quantifying their temperature-dependent structural properties (elastic modulus, shear modulus, and Poisson's ratio). It was observed that the Seebeck coefficient and resistivity increased only slightly in the double-filled In,Ce skutterudite materials upon thermal cycling. In the In-filled skutterudites the Seebeck coefficient remained approximately the same on thermal cycling, while electrical resistivity increased significantly after thermal cycling. Results also show that thermal conductivity marginally decreases in the case of In-filled skutterudites, whereas the reduction is more pronounced in In, Ce-based skutterudite compounds. The possible reason for this kind of reduction can be attributed to grain pinning effects due to formation of nano inclusions. High temperature structural property measurements (i.e., Young's modulus and shear modulus) are also reported and the results show that these structural properties decrease slowly as temperature increases and the compounds are structurally stable after numerous thermal cycles.

  17. Modeling circadian clock-cell cycle interaction effects on cell population growth rates.

    Science.gov (United States)

    El Cheikh, R; Bernard, S; El Khatib, N

    2014-12-21

    The circadian clock and the cell cycle are two tightly coupled oscillators. Recent analytical studies have shown counter-intuitive effects of circadian gating of the cell cycle on growth rates of proliferating cells which cannot be explained by a molecular model or a population model alone. In this work, we present a combined molecular-population model that studies how coupling the circadian clock to the cell cycle, through the protein WEE1, affects a proliferating cell population. We show that the cell cycle can entrain to the circadian clock with different rational period ratios and characterize multiple domains of entrainment. We show that coupling increases the growth rate for autonomous periods of the cell cycle around 24 h and above 48 h. We study the effect of mutation of circadian genes on the growth rate of cells and show that disruption of the circadian clock can lead to abnormal proliferation. Particularly, we show that Cry 1, Cry 2 mutations decrease the growth rate of cells, Per 2 mutation enhances it and Bmal 1 knockout increases it for autonomous periods of the cell cycle less than 21 h and decreases it elsewhere. Combining a molecular model to a population model offers new insight on the influence of the circadian clock on the growth of a cell population. This can help chronotherapy which takes benefits of physiological rhythms to improve anti-cancer efficacy and tolerance to drugs by administering treatments at a specific time of the day.

  18. Pervasive Effects of Aging on Gene Expression in Wild Wolves.

    Science.gov (United States)

    Charruau, Pauline; Johnston, Rachel A; Stahler, Daniel R; Lea, Amanda; Snyder-Mackler, Noah; Smith, Douglas W; vonHoldt, Bridgett M; Cole, Steven W; Tung, Jenny; Wayne, Robert K

    2016-08-01

    Gene expression levels change as an individual ages and responds to environmental conditions. With the exception of humans, such patterns have principally been studied under controlled conditions, overlooking the array of developmental and environmental influences that organisms encounter under conditions in which natural selection operates. We used high-throughput RNA sequencing (RNA-Seq) of whole blood to assess the relative impacts of social status, age, disease, and sex on gene expression levels in a natural population of gray wolves (Canis lupus). Our findings suggest that age is broadly associated with gene expression levels, whereas other examined factors have minimal effects on gene expression patterns. Further, our results reveal evolutionarily conserved signatures of senescence, such as immunosenescence and metabolic aging, between wolves and humans despite major differences in life history and environment. The effects of aging on gene expression levels in wolves exhibit conservation with humans, but the more rapid expression differences observed in aging wolves is evolutionarily appropriate given the species' high level of extrinsic mortality due to intraspecific aggression. Some expression changes that occur with age can facilitate physical age-related changes that may enhance fitness in older wolves. However, the expression of these ancestral patterns of aging in descendant modern dogs living in highly modified domestic environments may be maladaptive and cause disease. This work provides evolutionary insight into aging patterns observed in domestic dogs and demonstrates the applicability of studying natural populations to investigate the mechanisms of aging. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Anti-aging effect and gene expression profiling of dung beetle glycosaminoglycan in aged rats.

    Science.gov (United States)

    Ahn, Mi Young; Kim, Ban Ji; Kim, Ha Jeong; Hwang, Jae Sam; Jung, Yi-Sook; Park, Kun-Koo

    2017-01-01

    This study aimed to evaluate the anti-aging effect of a newly prepared insect-derived compound, dung beetle glycosaminoglycan (GAG), given intraperitoneally to old SD rats as part of their diet for 1 month. Insect GAG administration was found to be related to a reduction in oxidative damage, hepato-cellular biomarker levels, protein carbonyl content, and malondialdehyde concentration. The anti-aging-related molecular genetic mechanisms of dung beetle GAG are not yet fully elucidated. Catharsius molossus (a type of dung beetle) GAG (CaG) possessed anti-aging activities; it reduced the serum level of creatinine kinase, had aortic vasorelaxant activities and cardioprotective actions, and maintained a normal glucose level in treated rats. Microarray analysis was performed with a rat 30 K cDNA clone set array to identify the gene-expression profiles of 14-month-old SD rats treated with dung beetle glycosaminoglycan 5 mg/kg (CaG5) over a 1-month period, which was done to investigate its anti-aging effect as compared to that of either Bombus ignitus (a type of bumblebee) queen GAG 5 mg/kg (IQG5) or chondroitin sulfate 10 mg/kg. CaG5 and IQG5 had marked anti-inflammatory effects, bringing about inhibition of free fatty acid, uric acid, sGPT, IL-1 beta, and CK values. In addition, anticoagulant and antithrombotic effects were seen: the concentration of factor 1 (fibrinogen) was increased in CaG- treated rat plasma. The CaG5-treated rat group, compared to the control, displayed upregulation of 131 genes, including lipocalin 2 (Lbp) and a serine peptidase inhibitor, Kaszal type3 (Spink3), and 64 downregulated genes, including lysyl oxidase (Lox), serine dehydratase (sds), and retinol saturase (Retsat). Our data suggest that dung beetle glycosaminoglycan may be a helpful treatment for aged rats, which indicates its potential as a therapeutic biomaterial for aging.

  20. Performance Analysis of a Double-effect Adsorption Refrigeration Cycle with a Silica Gel/Water Working Pair

    Directory of Open Access Journals (Sweden)

    Atsushi Akisawa

    2010-10-01

    Full Text Available A numerical investigation of the double-effect adsorption refrigeration cycle is examined in this manuscript. The proposed cycle is based on the cascading adsorption cycle, where condensation heat that is produced in the top cycle is utilized as the driving heat source for the bottom cycle. The results show that the double-effect cycle produces a higher coefficient of performance (COP as compared to that of the conventional single-stage cycle for driving temperatures between 100 °C and 150 °C in which the average cycle chilled water temperature is fixed at 9 °C. Moreover, the COP of the double-effect cycle is more than twice that of the single-stage cycle when the temperature reaches 130 °C. It is also observed that the adsorbent mass ratio of the high temperature cycle (HTC to the low temperature cycle (LTC affects the performance of the double-effect adsorption refrigeration cycle.

  1. Effect of the menstrual cycle on inflammatory cytokines in the periodontium.

    Science.gov (United States)

    Khosravisamani, M; Maliji, G; Seyfi, S; Azadmehr, A; Abd Nikfarjam, B; Madadi, S; Jafari, S

    2014-12-01

    The effects of different levels of steroid hormones, as experienced during puberty, pregnancy and menopause, on the periodontium have been demonstrated, but changes in sex hormone levels during the menstrual cycle, and the influence of these changes on the periodontium, remain unresolved. The aim of this study was to investigate the effect of the menstrual cycle on the levels of interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival crevicular fluid and on periodontal clinical parameters, including the gingival bleeding index (GBI) and the modified gingival index (MGI), in periodontally healthy women. Twenty-seven periodontally healthy women with a regular menstrual cycle were included in the study. Clinical parameters, including the GBI, the MGI and the simplified oral health index, were recorded during menstruation, ovulation and premenstruation phases (e.g. on days 1-2, 12-14 and 22-24, respectively) of the menstrual cycle. Gingival crevicular fluid and unstimulated saliva were collected, at each study phase, for assessment of IL-1β, TNF-α, estrogen and progesterone. Both the GBI and the MGI increased significantly during the menstrual cycle, and were significantly higher during ovulation than during menstruation or premenstruation (p menstrual cycle ( p = 0.18). The levels of IL-1β and TNF-α increased during the different phases of the menstrual cycle, but only the change in the TNF-α concentration was significant ( p menstrual cycle influence the periodontium and induce inflammatory conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Age Effects on Cortical Thickness in Cognitively Normal Elderly Individuals

    Directory of Open Access Journals (Sweden)

    Sona Hurtz

    2014-07-01

    Full Text Available Background/Aims: Atrophy in both grey and white matter is found in normal aging. The prefrontal cortex and the frontal lobe white matter are thought to be the most affected regions. Our aim was to examine the effects of normal aging on cortical grey matter using a 3D quantitative cortical mapping method. Methods: We analyzed 1.5-tesla brain magnetic resonance imaging data from 44 cognitively normal elderly subjects using cortical pattern matching and cortical thickness analyses. Linear regression analysis was used to study the effect of age on cortical thickness. 3D map-wide correction for multiple comparisons was conducted with permutation analyses using a threshold of p Results: We found a significant negative association between age and cortical thickness in the right hemisphere (pcorrected = 0.009 and a trend level association in the left hemisphere (pcorrected = 0.081. Age-related changes were greatest in the sensorimotor, bilateral dorsal anterior cingulate and supplementary motor cortices, and the right posterior middle and inferior frontal gyri. Age effects greater in the medial than lateral visual association cortices were also seen bilaterally. Conclusion: Our novel method further validates that normal aging results in diffuse cortical thinning that is most pronounced in the frontal and visual association cortices.

  3. Resveratrol in mammals: effects on aging biomarkers, age-related diseases, and life span.

    Science.gov (United States)

    Marchal, Julia; Pifferi, Fabien; Aujard, Fabienne

    2013-07-01

    Through its antioxidant, anticarcinogenic, and anti-inflammatory properties, resveratrol has become a candidate for drug development in the context of aging studies. Scientific evidence has highlighted its potential as a therapeutic agent for cardiovascular diseases and some cancers but also as an antiaging molecule. Resveratrol is thought to mimic the beneficial effects of chronic and moderate calorie restriction. Nevertheless, no study has demonstrated the prolongation of life span in healthy nonobese mammal models. This review summarizes recent findings on the effects of resveratrol on aging and life span in mammals. In our opinion, more studies should be performed to assess the effects of a chronic dietary intake of resveratrol in long-lived species close to humans, such as nonhuman primates. This will certainly generate more evidence about the ability of resveratrol to achieve the physiological benefits that have been observed in small mammal laboratory models and feature the eventual unwanted secondary effects that may occur under high levels of resveratrol.

  4. Effect of age on sperm fertility potential: oocyte donation as a model.

    Science.gov (United States)

    Gallardo, E; Simón, C; Levy, M; Guanes, P P; Remohí, J; Pellicer, A

    1996-08-01

    To determine the effect of age on sperm fecundability using oocyte donation as an in vivo model. Oocyte donation and IVF programs at the Instituto Valenciano de Infertilidad. Retrospective study in which four groups of oocyte donation cycles were established according to age of the male providing the semen sample: group 1 (n = 31) 51 years, the oldest being 64 years. All donated oocytes were obtained from patients < 35 years old. Male age, sperm characteristics (volume, concentration, motility, morphology), fertilization, embryo quality, pregnancy, implantation, and abortion rates among recipients. Similar sperm characteristics in fresh as well as after preparation for IVF were observed among males of different ages. Fertilization, embryo quality, pregnancy, and implantation were similar among the established groups. The mean age of the females included in each group significantly increased from group 1 to group 4. Age (up to 64 years) does not affect sperm characteristics or its ability to fertilize human eggs. Similarly, embryo development in vitro as well as implantation in recipient uteri are not affected by age of the male providing the semen sample.

  5. The effect of age and demographics on rib shape.

    Science.gov (United States)

    Holcombe, Sven A; Wang, Stewart C; Grotberg, James B

    2017-08-01

    Elderly populations have a higher risk of rib fractures and other associated thoracic injuries than younger adults, and the changes in body morphology that occur with age are a potential cause of this increased risk. Rib centroidal path geometry for 20 627 ribs was extracted from computed tomography (CT) scans of 1042 live adult subjects, then fitted to a six-parameter mathematical model that accurately characterizes rib size and shape, and a three-parameter model of rib orientation within the body. Multivariable regression characterized the independent effect of age, height, weight, and sex on the rib shape and orientation across the adult population, and statistically significant effects were seen from all demographic factors (P rib end-to-end separation and rib aspect ratio are seen to increase with age, producing elongated and flatter overall rib shapes in elderly populations, with age alone explaining up to 20% of population variability in the aspect ratio of mid-level ribs. Age was not strongly associated with overall rib arc length, indicating that age effects were related to shape change rather than overall bone length. The rib shape effect was found to be more strongly and directly associated with age than previously documented age-related changes in rib angulation. Other demographic results showed height and sex being most strongly associated with rib size, and weight most strongly associated with rib pump-handle angle. Results from the study provide a statistical model for building rib shapes typical of any given demographic by age, height, weight, and sex, and can be used to help build population-specific computational models of the thoracic rib cage. Furthermore, results also quantify normal population ranges for rib shape parameters which can be used to improve the assessment and treatment of rib skeletal deformity and disease. © 2017 Anatomical Society.

  6. Effect Of Oceanic Lithosphere Age Errors On Model Discrimination

    Science.gov (United States)

    DeLaughter, J. E.

    2016-12-01

    The thermal structure of the oceanic lithosphere is the subject of a long-standing controversy. Because the thermal structure varies with age, it governs properties such as heat flow, density, and bathymetry with important implications for plate tectonics. Though bathymetry, geoid, and heat flow for young (geoid, and heat flow data to an inverse model to determine lithospheric structure details. Though inverse models usually include the effect of errors in bathymetry, heat flow, and geoid, they rarely examine the effects of errors in age. This may have the effect of introducing subtle biases into inverse models of the oceanic lithosphere. Because the inverse problem for thermal structure is both ill-posed and ill-conditioned, these overlooked errors may have a greater effect than expected. The problem is further complicated by the non-uniform distribution of age and errors in age estimates; for example, only 30% of the oceanic lithosphere is older than 80 MY and less than 3% is older than 150 MY. To determine the potential strength of such biases, I have used the age and error maps of Mueller et al (2008) to forward model the bathymetry for half space and GDH1 plate models. For ages less than 20 MY, both models give similar results. The errors induced by uncertainty in age are relatively large and suggest that when possible young lithosphere should be excluded when examining the lithospheric thermal model. As expected, GDH1 bathymetry converges asymptotically on the theoretical result for error-free data for older data. The resulting uncertainty is nearly as large as that introduced by errors in the other parameters; in the absence of other errors, the models can only be distinguished for ages greater than 80 MY. These results suggest that the problem should be approached with the minimum possible number of variables. For example, examining the direct relationship of geoid to bathymetry or heat flow instead of their relationship to age should reduce uncertainties

  7. Sex and Age Effects of Functional Connectivity in Early Adulthood.

    Science.gov (United States)

    Zhang, Chao; Cahill, Nathan D; Arbabshirani, Mohammad R; White, Tonya; Baum, Stefi A; Michael, Andrew M

    2016-11-01

    Functional connectivity (FC) in resting-state functional magnetic resonance imaging (rs-fMRI) is widely used to find coactivating regions in the human brain. Despite its widespread use, the effects of sex and age on resting FC are not well characterized, especially during early adulthood. Here we apply regression and graph theoretical analyses to explore the effects of sex and age on FC between the 116 AAL atlas parcellations (a total of 6670 FC measures). rs-fMRI data of 494 healthy subjects (203 males and 291 females; age range: 22-36 years) from the Human Connectome Project were analyzed. We report the following findings. (1) Males exhibited greater FC than females in 1352 FC measures (1025 survived Bonferroni correction; [Formula: see text]). In 641 FC measures, females exhibited greater FC than males but none survived Bonferroni correction. Significant FC differences were mainly present in frontal, parietal, and temporal lobes. Although the average FC values for males and females were significantly different, FC values of males and females exhibited large overlap. (2) Age effects were present only in 29 FC measures and all significant age effects showed higher FC in younger subjects. Age and sex differences of FC remained significant after controlling for cognitive measures. (3) Although sex [Formula: see text] age interaction did not survive multiple comparison correction, FC in females exhibited a faster cross-sectional decline with age. (4) Male brains were more locally clustered in all lobes but the cerebellum; female brains had a higher clustering coefficient at the whole-brain level. Our results indicate that although both male and female brains show small-world network characteristics, male brains were more segregated and female brains were more integrated. Findings of this study further our understanding of FC in early adulthood and provide evidence to support that age and sex should be controlled for in FC studies of young adults.

  8. The effect of normal aging and age-related macular degeneration on perceptual learning.

    Science.gov (United States)

    Astle, Andrew T; Blighe, Alan J; Webb, Ben S; McGraw, Paul V

    2015-01-01

    We investigated whether perceptual learning could be used to improve peripheral word identification speed. The relationship between the magnitude of learning and age was established in normal participants to determine whether perceptual learning effects are age invariant. We then investigated whether training could lead to improvements in patients with age-related macular degeneration (AMD). Twenty-eight participants with normal vision and five participants with AMD trained on a word identification task. They were required to identify three-letter words, presented 10° from fixation. To standardize crowding across each of the letters that made up the word, words were flanked laterally by randomly chosen letters. Word identification performance was measured psychophysically using a staircase procedure. Significant improvements in peripheral word identification speed were demonstrated following training (71% ± 18%). Initial task performance was correlated with age, with older participants having poorer performance. However, older adults learned more rapidly such that, following training, they reached the same level of performance as their younger counterparts. As a function of number of trials completed, patients with AMD learned at an equivalent rate as age-matched participants with normal vision. Improvements in word identification speed were maintained at least 6 months after training. We have demonstrated that temporal aspects of word recognition can be improved in peripheral vision with training across a range of ages and these learned improvements are relatively enduring. However, training targeted at other bottlenecks to peripheral reading ability, such as visual crowding, may need to be incorporated to optimize this approach.

  9. Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

  10. Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

    Science.gov (United States)

    Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

    2012-01-01

    The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

  11. When ageing meets the blues: Are current antidepressants effective in depressed aged patients?

    Science.gov (United States)

    Felice, Daniela; O'Leary, Olivia F; Cryan, John F; Dinan, Timothy G; Gardier, Alain M; Sánchez, Connie; David, Denis J

    2015-08-01

    "I had to wait 110 years to become famous. I wanted to enjoy it as long as possible.", Jeanne Louise Calment (1875-1997). This review summarizes current knowledge of the effects of antidepressant drugs in elderly patients (double-blind placebo (n=27) or active comparator-controlled clinical trials (n=21) indexed in Pubmed in depressed patients aged ≥60) and in aged mice (≥9 months) and middle-aged rats (≥14 months) on depression-related symptoms and cognitive performances. Finally, other potential therapeutic targets for treating depression-related disorders in elderly patients are also addressed (neurogenesis, GABAB receptor, 5-HT4 receptor, mTOR signaling). Overall, the very few published preclinical studies (n=12 in total) in middle-aged and aged rodents seem to suggest that selective serotonin reuptake inhibitors (SSRIs) may be less effective than tricyclic antidepressant drugs (TCAs) in ameliorating depression-like behavior and cognitive functions. On the other hand, results from clinical trials suggest that there is not a marked difference in efficacy and safety profiles of current marketed classes of antidepressant drugs.

  12. Effect of multiple freeze-thaw cycles on detection of measles, mumps, and rubella virus antibodies.

    Science.gov (United States)

    Pinsky, Norman A; Huddleston, Jeanne M; Jacobson, Robert M; Wollan, Peter C; Poland, Gregory A

    2003-01-01

    We investigated the effect of multiple freeze-thaw cycles on mumps, measles, and rubella virus serum antibody levels with whole-virus immunoglobulin G enzyme-linked immunoassays. Fresh serum samples from nine healthy adult volunteers were divided into six sets of five aliquots each. Samples were taken through a total of 10 freeze-thaw cycles and stored at 4 degrees C until assayed. Each assay measurement was done in replicates of five, and the mean value was reported. After completing 10 freeze-thaw cycles, we found no clinically or statistically significant effect on measured antibody levels and found no discernible detrimental effect on the ability to measure these antibodies by enzyme-linked immunoassays.

  13. Pervasive Drought Legacy Effects in Forest Ecosystems and their Carbon Cycle Implications

    Science.gov (United States)

    Anderegg, W.; Schwalm, C.; Biondi, F.; Camarero, J. J.; Koch, G. W.; Litvak, M. E.; Ogle, K.; Shaw, J.; Shevliakova, E.; Williams, P.; Wolf, A.; Ziaco, E.; Pacala, S. W.

    2015-12-01

    The impacts of climate extremes on terrestrial ecosystems are poorly understood but central for predicting carbon cycle feedbacks to climate change. Coupled climate-carbon cycle models typically assume that vegetation recovery from extreme drought is immediate and complete, which conflicts with basic plant physiological understanding. We examine the recovery of tree stem growth after severe drought at 1,338 forest sites globally comprising 49,339 site-years and compare it to simulated recovery in climate-vegetation models. We find pervasive and substantial "legacy effects" of reduced growth and incomplete recovery for 1-4 years after severe drought, and that legacy effects are most prevalent in dry ecosystems, Pinaceae, and species with low hydraulic safety margins. In contrast, no or limited legacy effects are simulated in current climate-vegetation models after drought. Our results highlight hysteresis in ecosystem carbon cycling and delayed recovery from climate extremes.

  14. The Moderating Effect of Frequent Singing on Voice Aging.

    Science.gov (United States)

    Lortie, Catherine L; Rivard, Julie; Thibeault, Mélanie; Tremblay, Pascale

    2017-01-01

    The effects of aging on voice production are well documented, including changes in loudness, pitch, and voice quality. However, one important and clinically relevant question that remains concerns the possibility that the aging of voice can be prevented or at least delayed through noninvasive methods. Indeed, discovering natural means to preserve the integrity of the human voice throughout aging could have a major impact on the quality of life of elderly adults. The objective of this study was therefore to examine the potentially positive effect of singing on voice production. To this aim, a group of 72 healthy nonsmoking adults (20-93 years old) was recruited and separated into three groups based on their singing habits. Several voice parameters were assessed (fundamental frequency [f0] mean, f0 standard deviation [SD], f0 minimum and f0 maximum, mean amplitude and amplitude SD, jitter, shimmer, and harmonic-to-noise ratio) during the sustained production of vowel /a/. Other parameters were assessed during standardized reading passage (speaking f0, speaking f0 SD). As was expected, age effects were found on most acoustic parameters with significant sex differences. Importantly, moderation analyses revealed that frequent singing moderates the effect of aging on most acoustic parameters. Specifically, in frequent singers, there was no decrease in the stability of pitch and amplitude with age, suggesting that the voice of frequent singers remains more stable in aging than the voice of non-singers, and more generally, providing empirical evidence for a positive effect of singing on voice in aging. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  15. Effects of aging on the male reproductive system.

    Science.gov (United States)

    Gunes, Sezgin; Hekim, Gulgez Neslihan Taskurt; Arslan, Mehmet Alper; Asci, Ramazan

    2016-04-01

    The study aims to discuss the effects of aging on the male reproductive system. A systematic review was performed using PubMed from 1980 to 2014. Aging is a natural process comprising of irreversible changes due to a myriad of endogenous and environmental factors at the level of all organs and systems. In modern life, as more couples choose to postpone having a child due to various socioeconomic reasons, research for understanding the effects of aging on the reproductive system has gained an increased importance. Paternal aging also causes genetic and epigenetic changes in spermatozoa, which impair male reproductive functions through their adverse effects on sperm quality and count as, well as, on sexual organs and the hypothalamic-pituitary-gonadal axis. Hormone production, spermatogenesis, and testes undergo changes as a man ages. These small changes lead to decrease in both the quality and quantity of spermatozoa. The offspring of older fathers show high prevalence of genetic abnormalities, childhood cancers, and several neuropsychiatric disorders. In addition, the latest advances in assisted reproductive techniques give older men a chance to have a child even with poor semen parameters. Further studies should investigate the onset of gonadal senesce and its effects on aging men.

  16. Canadian Provincial Population Growth: Fertility, Migration, and Age Structure Effects

    Directory of Open Access Journals (Sweden)

    Barry Edmonston

    2009-12-01

    Full Text Available The effect of changes in rates of mortality, fertility, and migration depend not only on the age-specific patterns and levels of these rates, but on the age structure of the population. In order to remove the influences of the age structure and concentrate on the impact of the demographic rates themselves, a common practice is to analyze the influences of the rates for a standard age structure. This paper adapts the general approach of using a standard age structure to a stationary population equivalent (SPE model, and analyzes current population change, using the SPE model, for provinces of Canada. Below-replacement fertility levels are only partially offset by net immigration. The SPE model evidences the decrease in the eventual provincial populations brought about by the below replacement fertility. Out-migration for some provinces to other areas of Canada accentuates their eventual population decreases.

  17. HIV and aging: effects on the central nervous system.

    Science.gov (United States)

    Cañizares, Silvia; Cherner, Mariana; Ellis, Ronald J

    2014-02-01

    With the introduction of combination antiretroviral therapy, many human immunodeficiency virus-positive (HIV+) individuals are reaching advanced age. The proportion of people living with HIV older than 50 years already exceeds 50% in many communities, and is expected to reach this level nationally by 2015. HIV and aging are independently associated with neuropathological changes, but their concurrence may have a more deleterious effect on the central nervous system (CNS). Published data about neurocognitive and neuroimaging markers of HIV and aging are reviewed. Putative factors contributing to neurocognitive impairment and neuroimaging changes in the aging HIV+ brain, such as metabolic disturbances, cardiovascular risk factors, immune senescence, and neuroinflammation, are described. The possible relationship between HIV and some markers of Alzheimer's disease is presented. Current research findings emphasize multiple mechanisms related to HIV and combination antiretroviral therapy that compromise CNS structure and function with advancing age.

  18. The Effect of Temperature on Key Aspects of the Nitrogen Cycle: Comparisons Across Systems

    Science.gov (United States)

    Warren, V.

    2016-02-01

    The nitrogen cycle sustains life by converting inert di-nitrogen gas (N2) into fixed bio-available forms (e.g. ammonium, nitrate), as well as returning it via gases such as N2 and nitrous oxide (N2O) back into the atmosphere. Recently, the effects of long term warming on key components of the carbon cycle, which is tightly coupled to the nitrogen cycle, have been highlighted but how global warming might systematically affect the balance of the nitrogen cycle is still largely unknown. The effect of long term warming on denitrification and nitrification were investigated using long-term, experimental mesocosm (2006 to present), allowing us to study the effect of warming on natural communities of bacteria involved in these processes. Denitrification activity responded to warming in the short-term in a predictable way, however, long-term moderate warming of 3-5oC (the predicted global increase by the end of the century) increased the specific activity of the sediment and had a pronounced effect on the ratio of N2O to N2. The latter suggesting that with sustained warming, denitrifying bacteria become more efficient at complete denitrification. Molecular analysis of denitrifying communities in our long-term mesocosm experiment also suggested a profound alteration of the communities underlying these differences in process. Similar short-term experiments were carried out on sediments and the water column of the North Eastern Tropical Pacific Oxygen minimum zone (NETP OMZ) including its effect on N2 fixation and here we contrast the findings from those markedly different settings. This research has indicated that we may see similar effects on the nitrogen cycle as we have previously determined in the carbon cycle, with the balance of N-species consumed and created becoming out of balance.

  19. Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, High-Cycle and Low-Cycle Mechanical Fatigue, Creep and Thermal Fatigue Effects

    Science.gov (United States)

    Bast, Callie C.; Boyce, Lola

    1995-01-01

    The development of methodology for a probabilistic material strength degradation is described. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing predictions of high-cycle mechanical fatigue and high temperature effects with experiments are presented. Results from this limited verification study strongly supported that material degradation can be represented by randomized multifactor interaction models.

  20. Secular trends in age at menarche and time to establish regular menstrual cycling in Japanese women born between 1930 and 1985

    Directory of Open Access Journals (Sweden)

    Hosokawa Michie

    2012-07-01

    Full Text Available Abstract Background Early life-stage exposure to estrogen increases the risk of breast cancer. The objective of this study was to investigate the age at menarche and time to onset of regular menstrual cycles for Japanese women born between 1930 and 1985. Methods A cross-sectional study was designed using data from the baseline survey of the Japan Nurses’ Health Study. The data from 48,104 female nurses were analyzed. To view trends in age at menarche, the distribution of age at menarche was calculated for each birth year cohort. The distribution of time to onset of regular menstrual cycles was calculated for each birth year cohort. To estimate whether high-risk group of the estrogenic dependent disorders increase with succeeding generations, we defined the women who experienced menarche at ten years old or younger and started a regular cycle within one year as early age onset of ovulatory cycles. Results Average ages at menarche were as follows: 13.8 years for those born in the 1930s (n = 113, 13.3 years for the 1940s (n = 4,751, 12.8 years for the 1950s (n = 15,844, 12.3 years for the 1960s (n = 20,547, 12.2 years for the 1970s (n = 6,568, and 12.2 years for the 1980s (n = 281. The proportion of women who experienced the onset of regular menstrual cycles 1 year after menarche was 29.3% for those born in the 1930s, but decreased to 11.9% for the 1980s. On the other hand, the proportion of women who did not have regular menstrual cycles was 10.4% for those born in the 1930s, but rose to 19.8% in 1980s. The proportion of women who experienced menarche at 10 years old and started regular menstrual cycles within one year increased over time: the percentage was 0.0%, 0.4%, 0.6%, 1.1%, 1.3%, and 2.1% for the women born in 1930s, 1940s, 1950s, 1960s, 1970s, and 1980s, respectively. Conclusions The age at menarche of Japanese women born between 1930 and 1985 decreased, but the onset of regular menstrual cycling

  1. Aging Effects on the Hydrogen Storage Characteristics of Li-Mg-B-N-H Complex Hydrides

    Science.gov (United States)

    Srinivasan, Sesha; Vickers, Eric; Mulharan, James; Darkazalli, Gazi; Goswami, Yogi; Stefanakos, Elias; FLPoly-CERC Collaboration

    2015-03-01

    The aging effects on the hydrogen storage characteristics and chemical formulations of the complex hydrides are discussed in this study. The aging effects due to atmospheric events such as oxygen and moisture coverage and self-decomposition are currently under investigation. The candidate material chosen for this study is Lithium/Magnesium based complex hydride LiBH4/LiNH2/MgH2. These materials were prepared using high energy ball milling under Ar/H2 atmosphere with different milling durations. The chemical, structural and microstructural characteristics of the synthesized and aged materials were compared and investigated using TGA/DSC, FTIR, XRD, BET and SEM analytical tools. Hydrogen storage properties such as hydrogen sorption kinetics, cycle life and pressure-composition isotherm (PCI) was examined via high pressure, high temperature Sievert's type apparatus. This current study will shed light to compare and contrast the above mentioned characteristics for the aged samples practically at the same experimental conditions. Furthermore, we have investigated the relationship between the aging effects with respect to the crystallite sizes of the candidate compounds and their nano-dopant variants. We acknowledge the grant from Florida Energy Systems Consortium and support from Florida Polytechnic University.

  2. Resveratrol and novel potent activators of SIRT1: effects on aging and age-related diseases.

    Science.gov (United States)

    Knutson, Mitchell D; Leeuwenburgh, Christiaan

    2008-10-01

    Studies show that the plant polyphenol resveratrol can extend the life span of yeast, worms, flies, and fish. It also mitigates the metabolic dysfunction of mice fed high-fat diets. Resveratrol appears to mediate these effects partly by activating SIRT1, a deacetylase enzyme that regulates the activity of several transcriptional factors and enzymes responsive to nutrient availability. However, few foods contain resveratrol and humans metabolize it extensively, resulting in very low systemic bioavailability. Substantial research effort now focuses on identifying and testing more bioavailable and potent activators of SIRT1 for use as pharmacologic interventions in aging and age-related disorders.

  3. Effects of aging and education on false memory.

    Science.gov (United States)

    Lee, Yuh-Shiow; Lee, Chia-Lin; Yang, Hua-Te

    2012-01-01

    This study examined the effects of aging and education on participants' false memory for words that were not presented. Three age groups of participants with either a high or low education level were asked to study lists of semantically related words. Both age and education were found to affect veridical and false memory, as indicated in the recall and recognition of the studied word and nonstudied lures. A low education level had a negative effect on memory performance for both young and middle-aged adults. Older adults with a high level of education had a higher level of false memory than those with a lower education level. The results of this study are discussed in terms of the importance of education on false memory and mechanisms that create false memory of words in older adults.

  4. Attention enhancing effects of methylphenidate are age-dependent.

    Science.gov (United States)

    Bhattacharya, Shevon E; Shumsky, Jed S; Waterhouse, Barry D

    2015-01-01

    The psychostimulant methylphenidate (MPH, Ritalin®) is used to treat a variety of cognitive disorders. MPH is also popular among healthy individuals, including the elderly, for its ability to focus attention and improve concentration, but these effects have not been shown to be comparable between aged and adult subjects. Thus, we tested whether MPH would improve performance in sustained attention in both adult and aged rats. In addition, we tested the impact of visual distraction on performance in this task and the ability of MPH to mitigate the effects of distraction. Adult (6-12 months) and aged (18-22 months) male Sprague-Dawley rats were given oral MPH, and their cognitive and motor abilities were tested. Results suggest that while MPH improves task performance in adults; there is no improvement in the aged animals. These outcomes suggest that the use of MPH for cognitive enhancement in elderly individuals may be ineffective.

  5. The Effects of Aging on Clinical Vestibular Evaluations.

    Science.gov (United States)

    Maheu, Maxime; Houde, Marie-Soleil; Landry, Simon P; Champoux, François

    2015-01-01

    Balance disorders are common issues for aging populations due to the effects of normal aging on peripheral vestibular structures. These changes affect the results of vestibular function evaluations and make the interpretation of these results more difficult. The objective of this article is to review the current state of knowledge of clinically relevant vestibular measures. We will first focus on otolith function assessment methods cervical-VEMP (cVEMP) and ocular-VEMP (oVEMP), then the caloric and video-head impulse test (vHIT) methods for semicircular canals assessment. cVEMP and oVEMP are useful methods, though research on the effects of age for some parameters are still inconclusive. vHIT results are largely independent of age as compared to caloric stimulation and should therefore be preferred for the evaluation of the semicircular canals function.

  6. The effects of aging on clinical vestibular evaluations

    Directory of Open Access Journals (Sweden)

    Maxime eMaheu

    2015-09-01

    Full Text Available Balance disorders are common issues for aging populations due to the effects of normal aging on peripheral vestibular structures. These changes affect the results of vestibular function evaluations and make the interpretation of these results more difficult. The objective of this article is to review the current state of knowledge of clinically relevant vestibular measures. We will first focus on otolith function assessment methods cVEMP and oVEMP, then the caloric and vHIT methods for semi-circular canals assessment. cVEMP and oVEMP are useful methods, though research on the effects of age for some parameters are still inconclusive. vHIT results are largely independent of age as compared to caloric stimulation and should therefore be preferred for the evaluation of the semi-circular canals function.

  7. What is normal in normal aging? Effects of aging, amyloid and Alzheimer's disease on the cerebral cortex and the hippocampus

    OpenAIRE

    Fjell, Anders M.; McEvoy, Linda; Holland, Dominic; Dale, Anders M; Walhovd, Kristine B.

    2014-01-01

    What can be expected in normal aging, and where does normal aging stop and pathological neurodegeneration begin? With the slow progression of age-related dementias such as Alzheimer's disease (AD), it is difficult to distinguish age-related changes from effects of undetected disease. We review recent research on changes of the cerebral cortex and the hippocampus in aging and the borders between normal aging and AD. We argue that prominent cortical reductions are evident in fronto-temporal reg...

  8. The regulatory effects of radiation and histone deacetylase inhibitor on liver cancer cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho; Choi, Hyung Seok; Jang, Dong Gun; Lee, Hong Je; Yang, Seoung Oh [Dept. Nuclear Medicine, Dongnam Institute of Radiological and Medicine Sciences Cancer Center, Busan (Korea, Republic of)

    2013-11-15

    Radiation has been an effective tool for treating cancer for a long time. Radiation therapy induces DNA damage within cancer cells and destroys their ability to reproduce. Radiation therapy is often combined with other treatments, like surgery and chemotherapy. Here, we describe the effects of radiation and histone deacetylase inhibitor, Trichostain A, on cell cycle regulation in hepatoma cells. Results demonstrate that the treatment of radiation TSA induces cell cycle arrest, thereby stimulating cell death in hepatoma cells. In addition, since different cells or tissues have different reactivity to radiation and TSA, these results might be an indicator for the combination therapy with radiation and drugs in diverse cancers.

  9. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China

    DEFF Research Database (Denmark)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere Abdisa

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling...... and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle....

  10. Thermal cycling effect of dicalcium phosphate-reinforced composites on auto-mineralized dental resin.

    Science.gov (United States)

    Chen, Wen-Cheng; Chang, Kai-Chi; Wu, Hui-Yu; Ko, Chia-Ling; Huang, Chien-Lin

    2014-12-01

    The mineralizing capabilities of surface-modified dicalcium phosphate anhydrous (DCPA), reinforced and treated with nanocrystals and capped with silane, in composite resins were analyzed via thermal cycling. We compared two light-curable composites that were mixed at filler-to-resin mass ratios of 30/70 and 50/50. The strengths, elastic moduli, and topographical structures of the samples were determined after thermal cycling between 5 and 55°C in deionized water for 600 and 2400 cycles. Silane-capped particles decreased the strength but enhanced the mineralizing capability of the composites. Nanocrystal-treated filler surfaces significantly increased the strength and moduli of the composites after 600 thermal cycles. However, these values declined after 2400 thermal cycles. The nanocrystal-treated filler surfaces prevented the reduction in strength before and after 2400 thermal cycles. Prior to silane capping, the nanocrystal-treated DCPA filler surfaces exhibited good mineralization capability without compromising strength. The potential for barrier generation through mineralization yielded positive effects and prevented micro-leakages. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The Effect of Menstrual Cycle on Singing Voice: A Systematic Review.

    Science.gov (United States)

    Gunjawate, Dhanshree R; Aithal, Venkataraja U; Ravi, Rohit; Venkatesh, Bhumika T

    2017-03-01

    Research has reported the difference in a woman's voice across the different stages of the menstrual cycle. A review of the studies in singers on the influence of menstruation on the singing voice will enable a better understanding of these changes. A systematic literature search was carried out on PubMed, CINAHL, Scopus, Cochrane, and regional electronic databases. The keywords "menstrual cycle," "voice change," and "singer" were used in different combinations. Only those articles that discussed the effect of menstrual cycle on the singing voice were included in the final review. Six studies in the English language were identified and included in the review. Hormonal variations occur to a great extent during menstrual cycle, and these variations can influence the voice of singers. A great variability was found in the included studies. There are limited studies that have been carried out exploring the relationship between menstrual cycle and the singing voice. Even though the studies included in the review point out toward the changes in the singing voice associated with menstrual cycle, there is a need for more studies to be carried out in diverse singing populations and in different outcome measures. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  12. Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy.

    Science.gov (United States)

    Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman

    2016-01-01

    Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autoclave, 1 autoclave cycle, 5 autoclave cycles and 10 autoclave cycles) by SEM under 200× and 1000× magnifications. Data were analyzed using the SPSS software and the paired sample t-test, independent sample t-test and multifactorial repeated measures ANOVA. The level of significance was set at 0.05. New files had debris and pitting on their surfaces. When the autoclave cycles were increased, the mean of surface roughness also increased at both magnifications (Pautoclave increased the surface roughness of the files and this had was directly related to the number of autoclave cycles.

  13. Protective Effects of Hydrogen Sulfide in the Ageing Kidney.

    Science.gov (United States)

    Hou, Cui-Lan; Wang, Ming-Jie; Sun, Chen; Huang, Yong; Jin, Sheng; Mu, Xue-Pan; Chen, Ying; Zhu, Yi-Chun

    2016-01-01

    Aims. The study aimed to examine whether hydrogen sulfide (H2S) generation changed in the kidney of the ageing mouse and its relationship with impaired kidney function. Results. H2S levels in the plasma, urine, and kidney decreased significantly in ageing mice. The expression of two known H2S-producing enzymes in kidney, cystathionine γ-lyase (CSE) and cystathionine-β-synthase (CBS), decreased significantly during ageing. Chronic H2S donor (NaHS, 50 μmol/kg/day, 10 weeks) treatment could alleviate oxidative stress levels and renal tubular interstitial collagen deposition. These protective effects may relate to transcription factor Nrf2 activation and antioxidant proteins such as HO-1, SIRT1, SOD1, and SOD2 expression upregulation in the ageing kidney after NaHS treatment. Furthermore, the expression of H2S-producing enzymes changed with exogenous H2S administration and contributed to elevated H2S levels in the ageing kidney. Conclusions. Endogenous hydrogen sulfide production in the ageing kidney is insufficient. Exogenous H2S can partially rescue ageing-related kidney dysfunction by reducing oxidative stress, decreasing collagen deposition, and enhancing Nrf2 nuclear translocation. Recovery of endogenous hydrogen sulfide production may also contribute to the beneficial effects of NaHS treatment.

  14. Differential effects of young maternal age on child growth

    Directory of Open Access Journals (Sweden)

    Soo Hyun Yu

    2016-11-01

    Full Text Available Background: The association of early maternal birthing age with smaller children has been widely observed. However, it is unclear if this is due to confounding by factors such as socioeconomic status, or the age at which child growth restriction first occurs. Objective: To examine the effect of early maternal birthing age on the first-born child's height-for-age in a sample of developing countries in Africa, Asia, and Latin America. Design: Cross-sectional data from Demographic Health Surveys from 18 countries were used, to select the first-born child of mothers aged 15–24 years and a range of potential confounding factors, including maternal height. Child length/height-for-age z-scores (HAZs was estimated in age bands of 0–11, 12–23, 24–35, 36–47, and 48–59 months; HAZ was first compared between maternal age groups of 15–17, 18–19, and 20–24 years. Results: 1 There were significant bivariate associations between low child HAZ and young maternal age (71 of 180 possible cases; at p<0.10, but the majority of these did not persist when controlling for confounders (41 cases, 23% of the 180. 2 For children <12 months, when controlling for confounders, three out of seven Asian countries showed a significant association between lower infant HAZ and low maternal age, as did six out of nine African countries (15–17 or 15–19 years vs. the older group. 3 The association (adjusted continued after 24 months in 12 of the 18 countries, in Africa, Asia, and Latin America. 4 The stunting differences for children between maternal age groups were around 9 percentage points (ppts in Asia, 14 ppts in Africa, and 10 ppts in Latin America. These data do not show whether this is due to, for example, socioeconomic factors that were not included, an emerging effect of intrauterine growth restriction, or the child feeding or caring behaviors of young mothers. The latter is considered to be the most likely. Conclusions: The effect of low maternal age

  15. Ageing under Shear: Effect of Stress and Temperature Field

    Science.gov (United States)

    Shukla, Asheesh; Joshi, Yogesh M.

    2008-07-01

    In this work we studied the effect of oscillatory stress and temperature on the ageing dynamics of aqueous suspension of laponite. At the higher magnitude of stress, elastic and viscous moduli of the system underwent a sharp rise with the ageing time. The age at the onset of rise and the sharpness of the same increased with the magnitude of stress. We propose that at the beginning of ageing, the strain associated with the oscillatory stress field affects the lower modes in the relaxation time distribution. The higher modes, which are not significantly affected by the deformation field, continue to grow increasing the viscosity of the system thereby lowering the magnitude of the deformation field. Progressive decrease in the later reduces the range of relaxation modes affected by it. This dynamics eventually leads to an auto-catalytic increase in the elastic and viscous moduli. An increase in temperature accelerates the ageing process by shifting the ageing dynamics to a lower ageing time. This is due the microscopic relaxation dynamics, which causes ageing, becomes faster with increase in the temperature.

  16. Is age really cruel to experts? Compensatory effects of activity.

    Science.gov (United States)

    Vaci, Nemanja; Gula, Bartosz; Bilalić, Merim

    2015-12-01

    Age-related decline may not be as pronounced in complex activities as it is in basic cognitive processes, but ability deterioration with age is difficult to deny. However, studies disagree on whether age is kinder to more able people than it is to their less able peers. In this article, we investigated the "age is kinder to the more able" hypothesis by using a chess database that contains activity records for both beginners and world-class players. The descriptive data suggested that the skill function across age captures the 3 phases as described in Simonton's model of career trajectories: initial rise to the peak of performance, postpeak decline, and eventual stabilization of decline. We therefore modeled the data with a linear mixed-effect model using the cubic function that captures 3 phases. The results show that age may be kind to the more able in a subtler manner than has previously been assumed. After reaching the peak at around 38 years, the more able players deteriorated more quickly. Their decline, however, started to slow down at around 52 years, earlier than for less able players (57 years). Both the decline and its stabilization were significantly influenced by activity. The more players engaged in playing tournaments, the less they declined and the earlier they started to stabilize. The best experts may not be immune to aging, but their previously acquired expertise and current activity enable them to maintain high levels of skill even at an advanced age.

  17. Leukocyte telomere length: Effects of schizophrenia, age, and gender.

    Science.gov (United States)

    Wolkowitz, Owen M; Jeste, Dilip V; Martin, Averria Sirkin; Lin, Jue; Daly, Rebecca E; Reuter, Chase; Kraemer, Helena

    2017-02-01

    Schizophrenia is linked with early medical comorbidity and mortality. These observations indicate possible "accelerated biological aging" in schizophrenia, although prior findings are mixed, and few such studies have examined the role of gender. One putative marker of biological aging is leukocyte telomere length (LTL), which typically shortens with age. We assessed LTL in phenotypically well characterized 134 individuals with schizophrenia (60 women and 74 men) and 123 healthy comparison subjects (HCs) (66 women and 57 men), aged 26 to 65 years. Overall, LTL was inversely associated with age (t(249) = -6.2, p schizophrenia and HC groups (t(249) = 2.48, p = 0.014), with women having longer LTL than men, and a significant gender X diagnosis effect (t(249) = 2.43, p = 0.016) - at the average sample age, women with schizophrenia had shorter LTL than HC women. Gender, not the diagnosis of schizophrenia, was the major factor involved with LTL shortening across the age range studied. We discuss the constraints of a cross-sectional design and other methodological issues, and indicate future directions. Understanding the impact of schizophrenia on biological aging will require separate evaluations in men and women. Published by Elsevier Ltd.

  18. Old age and the associated impairment of bones' adaptation to loading are associated with transcriptomic changes in cellular metabolism, cell-matrix interactions and the cell cycle.

    Science.gov (United States)

    Galea, Gabriel L; Meakin, Lee B; Harris, Marie A; Delisser, Peter J; Lanyon, Lance E; Harris, Stephen E; Price, Joanna S

    2017-01-30

    In old animals, bone's ability to adapt its mass and architecture to functional load-bearing requirements is diminished, resulting in bone loss characteristic of osteoporosis. Here we investigate transcriptomic changes associated with this impaired adaptive response. Young adult (19-week-old) and aged (19-month-old) female mice were subjected to unilateral axial tibial loading and their cortical shells harvested for microarray analysis between 1h and 24h following loading (36 mice per age group, 6 mice per loading group at 6 time points). In non-loaded aged bones, down-regulated genes are enriched for MAPK, Wnt and cell cycle components, including E2F1. E2F1 is the transcription factor most closely associated with genes down-regulated by ageing and is down-regulated at the protein level in osteocytes. Genes up-regulated in aged bone are enriched for carbohydrate metabolism, TNFα and TGFβ superfamily components. Loading stimulates rapid and sustained transcriptional responses in both age groups. However, genes related to proliferation are predominantly up-regulated in the young and down-regulated in the aged following loading, whereas those implicated in bioenergetics are down-regulated in the young and up-regulated in the aged. Networks of inter-related transcription factors regulated by E2F1 are loading-responsive in both age groups. Loading regulates genes involved in similar signalling cascades in both age groups, but these responses are more sustained in the young than aged. From this we conclude that cells in aged bone retain the capability to sense and transduce loading-related stimuli, but their ability to translate acute responses into functionally relevant outcomes is diminished.

  19. Mind the gap: the distributional effects of raising the early eligibility age and full retirement age.

    Science.gov (United States)

    Olsen, Anya

    2012-01-01

    Policymakers have proposed increases to the early eligibility age (EEA) and/or full retirement age (FRA) to address increasing life expectancy and Social Security solvency issues. This analysis uses the Social Security Administration's Modeling Income in the Near Term, version 6 (MINT6) model to compare three retirement-age increases suggested by the Social Security Advisory Board: increase the gap between the EEA and FRA by raising only the FRA, increase both the EEA and FRA to maintain a 4-year gap between them, and increase both the EEA and FRA to maintain a 5-year gap between them. Although all three options would improve system solvency by similar proportions, their effect on individual beneficiaries in the future would vary. Benefit reductions are greater under the proposals with more months between the EEA and FRA, while the option that maintains a 4-year gap results in benefit increases for some beneficiaries compared with current law.

  20. Effect of duty-cycles on the air plasma gas-phase of dielectric barrier discharges

    Science.gov (United States)

    Barni, R.; Biganzoli, I.; Dell'Orto, E. C.; Riccardi, C.

    2015-10-01

    An experimental investigation concerning the effects of a duty-cycle in the supply of a dielectric barrier discharge in atmospheric pressure air has been performed. Electrical characteristics of the discharge have been measured, focusing mainly on the statistical properties of the current filaments and on dielectric surface charging, both affected by the frequent repetition of breakdown imposed by the duty-cycle. Information on the gas-phase composition was gathered too. In particular, a strong enhancement in the ozone formation rate is observed when suitable long pauses separate the active discharge phases. A simulation of the chemical kinetics in the gas-phase, based on a simplified discharge modeling, is briefly described in order to shed light on the observed increase in ozone production. The effect of a duty-cycle on surface modification of polymeric films in order to increase their wettability has been investigated too.

  1. The Effects of Internal and External Irreversibility of a Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Wang, Fu-Jen; Chiou, Jeng-Shing

    The concept of finite-time thermodynamics is employed to investigate the optimal refrigeration rate for an irreversible refrigeration cycle. The heat transfer between the system (internal) fluid and cooling (external) fluid takes place at the actual heat exchanger, which has the finite-size heat transfer area and the realistic heat transfer effectiveness. The internal irreversibility results from the compression process and the expansion process are also considered. The optimal refrigeration rate is calculated and expressed in terms of the irreversibility parameter (Ir), coefficient of performance (COP), the time ratio(γ) of heat transfer processes and the effectiveness of heat exchanger. The derived COP which consider both the external and internal irreversibility can thus be considered as the benchmark value for a practical refrigeration cycle, and the parametric study can provide the basis for both determination of optimal operating conditions and design of a practical refrigeration cycle.

  2. A synergetic hybridization of adsorption cycle with the multi-effect distillation (MED)

    KAUST Repository

    Thu, K.

    2014-01-01

    Multi-effect distillation (MED) systems are proven and energy efficient thermally-driven desalination systems for handling harsh seawater feed in the Gulf region. The high cycle efficiency is markedly achieved by latent energy re-use with minimal stage temperature-difference across the condensing steam and the evaporating saline seawater in each stage. The efficacies of MED system are (i) its low stage-temperature-difference between top brine temperature (TBT) and final condensing temperature, (ii) its robustness to varying salinity and ability to handle harmful algae Blooming (HABs) and (iii) its compact foot-print per unit water output. The practical TBT of MED systems, hitherto, is around 65 C for controllable scaling and fouling with the ambient-limited final condenser temperature, usually from 30 to 45 C. The adsorption (ADC) cycles utilize low-temperature heat sources (typically below 90 C) to produce useful cooling power and potable water. Hybridizing MED with AD cycles, they synergistically improve the water production rates at the same energy input whilst the AD cycle is driven by the recovered waste heat. We present a practical AD + MED combination that can be retrofitted to existing MEDs: The cooling energy of AD cycle through the water vapor uptake by the adsorbent is recycled internally, providing lower temperature condensing environment in the effects whilst the final condensing temperature of MED is as low as 5-10 C, which is below ambient. The increase in the temperature difference between TBT and final condensing temperature accommodates additional MED stages. A detailed numerical model is presented to capture the transient behaviors of heat and mass interactions in the combined AD + MED cycles and the results are presented in terms of key variables. It is observed that the water production rates of the combined cycle increase to give a GOR of 8.8 from an initial value of 5.9. © 2013 Elsevier Ltd. All rights reserved.

  3. Effect of curcumin on aging retinal pigment epithelial cells

    Directory of Open Access Journals (Sweden)

    Zhu W

    2015-09-01

    Full Text Available Wei Zhu,1,* Yan Wu,2,* Yi-Fang Meng,1 Jin-Yu Wang,1 Ming Xu,1 Jian-Jun Tao,1 Jiong Lu1 1Department of Ophthalmology, Changshu No 2 People’s Hospital, Changshu, 2Department of Ophthalmology, The First People’s Hospital of Kunshan Affiliated with Jiangsu University, Suzhou, People’s Republic of China *These authors contributed equally to this work Abstract: Age-related macular degeneration (AMD is now one of the leading causes of blindness in the elderly population. The antioxidative effects of curcumin on aging retinal pigment epithelial (RPE cells are still unclear. We conducted an in vitro study to investigate the effects of curcumin on aging RPE cells. A pulsed H2O2 exposure aging model was adopted. Aging RPE cells were treated with curcumin 20 µM, 40 µM, and 80 µM. Apoptosis of RPE cells was analyzed by flow cytometry. The intracellular reactive oxygen species concentration was detected using a specific probe and apoptosis-associated proteins were detected by Western blot. Expression of oxidative biomarkers, including superoxide dismutase, maleic dialdehyde, and glutathione, was detected commercially available assay kits. Compared with normal cells, lower cell viability, higher apoptosis rates, and more severe oxidation status were identified in the aging RPE cell model. Curcumin improved cell viability and decreased apoptosis and oxidative stress. Further, curcumin had a significant influence on expression of apoptosis-associated proteins and oxidative stress biomarkers. In conclusion, treatment with curcumin was able to regulate proliferation, oxidative stress, and apoptosis in aging RPE cells. Accordingly, application of curcumin may be a novel strategy to protect against age-related change in AMD. Keywords: curcumin, retinal pigment epithelium, apoptosis, age-related macular degeneration

  4. Effects of aging on eye movements in the real world.

    Science.gov (United States)

    Dowiasch, Stefan; Marx, Svenja; Einhäuser, Wolfgang; Bremmer, Frank

    2015-01-01

    The effects of aging on eye movements are well studied in the laboratory. Increased saccade latencies or decreased smooth-pursuit gain are well established findings. The question remains whether these findings are influenced by the rather untypical environment of a laboratory; that is, whether or not they transfer to the real world. We measured 34 healthy participants between the age of 25 and 85 during two everyday tasks in the real world: (I) walking down a hallway with free gaze, (II) visual tracking of an earth-fixed object while walking straight-ahead. Eye movements were recorded with a mobile light-weight eye tracker, the EyeSeeCam (ESC). We find that age significantly influences saccade parameters. With increasing age, saccade frequency, amplitude, peak velocity, and mean velocity are reduced and the velocity/amplitude distribution as well as the velocity profile become less skewed. In contrast to laboratory results on smooth pursuit, we did not find a significant effect of age on tracking eye-movements in the real world. Taken together, age-related eye-movement changes as measured in the laboratory only partly resemble those in the real world. It is well-conceivable that in the real world additional sensory cues, such as head-movement or vestibular signals, may partially compensate for age-related effects, which, according to this view, would be specific to early motion processing. In any case, our results highlight the importance of validity for natural situations when studying the impact of aging on real-life performance.

  5. [Anti-aging Effect of Urtica Polysaccharides in D-galactose Induced Aging Mice].

    Science.gov (United States)

    Jing, Bo; Lv, Cheng; Li, Shun-xu; FU, Mei-ling; Yin, Zhong-qiong

    2015-12-01

    To investigate the anti-aging effect of polysaccharides from Urtica lobatifolia (Urtica polysaccharides) on subacute aging mice induced by D-galactose. 90 mice were randomly divided into six groups: normal group, aging mice model group, V(E) group [100 mg/(kg x d), ig], high level of Urtica polysaccharides group [200 mg/(kg x d), ig], medium level of Urtica polysaccharides group [100 mg/(kg x d), ig] and low level of Urtica polysaccharides group [50 mg/(kg x d), ig]. The normal group was injected saline [10 mL/(kg x d), sc], while the other groups were injected D-galactose [150 mg/(kg x d), sc]. After six weeks, all the animals were weighed. After eight arm maze experiment and swimming endurance experiment, serum, liver and brain was collected. The content of protein in serum,liver and brain was detected. Total antioxidant capacity (T-AOC), activities of total superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) content in liver and brain samples were evaluated by kits. Compared with the model group, Urtica polysaccharides groups mice had larger body weight, longer swimming time, shorter time out of the maze and fewer numbers of error, as well as higher protein content in serum, liver and brain. The capacity of T-AOC, the activities of SOD and GSH-Px of polysaccharides groups in brain and liver tissue were increased significantly, and the MDA content was decreased significantly. Polysaccharides from Urtica lobatifolia has anti-aging effects on aging model mice, and the mechanism may be related to its antioxidant effect.

  6. Effects of solar UV radiation and climate change on biogeochemical cycling: interactions and feedbacks

    OpenAIRE

    Zepp, R. G.; D. J. Erickson; Paul, N.D.; Sulzberger, B.

    2011-01-01

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions of these effects with climate change, including feedbacks on climate. Such interactions occur in both terrestrial and aquatic ecosystems. While there is significant uncertainty in the quantification of these effects,...

  7. Menstrual cycle phase effects free testosterone responses to prolonged aerobic exercise.

    Science.gov (United States)

    Lane, A R; O'Leary, C B; Hackney, A C

    2015-09-01

    Research has shown that total testosterone (tT) levels in women increase acutely during a prolonged bout of aerobic exercise. Few studies, however, have considered the impact of the menstrual cycle phase on this response or have looked at the biologically active free testosterone (fT) form responses. Therefore, this study examined the fT concentration response independently and as a percentage (fT%) of tT to prolonged aerobic exercise during phases of the menstrual cycle with low estrogen-progesterone (L-EP; i.e., follicular phase) and high estrogen-progesterone (H-EP; i.e., luteal phase). Ten healthy, recreationally trained, eumennorrheic women (X ± SD: age = 20 ± 2 y, mass = 58.7 ± 8.3 kg, body fat = 22.3 ± 4.9 %, VO(2max) = 50.7 ± 9.0 ml/kg/min) participated in a laboratory based study and completed a 60-minute treadmill run during the L-EP and H-EP menstrual phases at ~70% of VO(2max). Blood was drawn prior to (PRE), immediately after (POST) and following 30 minutes of recovery (30POST) with each 60-minute run. During H-EP, there was a significant increase in fT concentrations from PRE to POST (p exercise sampling time. There was, however, a main effect for exercise where fT% POST was a greater proportion of tT than at PRE (p exercise bout; specifically, there being higher levels under H-EP conditions. This suggests more biologically active T is available during exercise in this phase. This response may be a function of the higher core temperatures found with H-EP causing greater sex hormone binding protein release of T, or could be a function of greater degrees of glandular production. Further work is warranted to elucidate the mechanism of this occurrence. It is recommended that researchers examining T responses to exercise in women look at both tT and fT forms in order to have an accurate endocrine assessment in women.

  8. Effect of menstrual cycle phase on glucose kinetics in healthy women & women with premenstrual symptoms.

    Directory of Open Access Journals (Sweden)

    Meena K. Nandimath

    2015-11-01

    Full Text Available Objective: To compare the blood glucose levels during the two phases of the menstrual cycle between healthy women and patients with premenstrual syndrome (PMS.Methods: From January of 2012 to the August of 2013, a descriptive cross-sectional study was performed among staff of tertiary care hospital.Inclusion Criteria: 1100 women aged 18 to 45 years, 2 Regular Menstrual cycle.Exclusion Criteria: 1 Menopause 2 Patient on Oral Contraceptive pills.After approval from IEC and informed consent from the 100 enrolled subjects with either the most severe symptoms of PMS or healthy controls. 2ml of venous blood was collected on fasting condition during the follicular phase (5-11 days of  menstrual cycleand the luteal phase of the cycle (19-28 days menstrual cycle and analyzed the serum concentrations of glucose by using the glucose oxidase method.Results: The statistical analysis was done using student's paired T test. P value less than 0.0001was taken as significant.No significant differences between the demographic data of the control and PMS groups were observed. The mean concentrations of glucose were significantly different during the follicular and luteal phases.

  9. Effects of short-term cycling on knee joint proprioception in ACL-deficient patients.

    Science.gov (United States)

    Roberts, David; Ageberg, Eva; Andersson, Gert; Fridén, Thomas

    2004-09-01

    It has previously been shown that knee injuries with ACL ruptures may lead to decreased proprioception and that exercise in a normal population, uninjured individuals, may reduce the proprioceptive ability. How proprioception is affected by exercise in patients with ACL deficiency has, to our knowledge, not been studied before. Knee joint proprioception was estimated in 36 patients, 18 males and 18 females, with ACL deficiency by measuring thresholds for detection of slow passive motion before and after a short period of exercise on an ergometer bicycle. In addition, the results were compared with a control group of 24 individuals of the same age. We found trends of enhanced proprioception towards extension in the patient group after cycling, but not in the control group. Towards flexion, both groups showed poorer proprioception after cycling. When difference scores of proprioceptive change in each group were compared, a trend towards different reaction upon cycling between the groups was seen in measurement towards extension from 20 degrees where the patients seemed to improve proprioception, which the controls did not. The results are not conclusive in this pilot study, but the possibility that ACL-deficient patients and controls may not react likewise to cycling, as regards their proprioceptive ability, is discussed.

  10. Effect of surface treatment of brackets and mechanical cycling on adhesion to enamel.

    Science.gov (United States)

    Arrais, Fabiola Rossato; Degrazia, Felipe; Peres, Bernardo Urbanetto; Ferrazzo, Vilmar Antonio; Grehs, Renesio Armindo; Valandro, Luiz Felipe

    2014-01-01

    This in vitro study sought to evaluate how surface conditioning from bracket and mechanical cycling aging affected the bond strength between metallic brackets and bovine enamel, and to determine the adhesive remnant index. Eighty bovine incisors were embedded in acrylic resin using polyvinyl chloride rings and divided into 4 groups based on surface treatment (n = 20). Group 1 (control) received no surface treatment, Group 2 specimens were sandblasted with aluminum oxide particles, Group 3 specimens were sandblasted with silicon oxide and treated with a tribochemichemical silica coupling agent, and Group 4 specimens were primed with a multidomain protein-based agent. Half of the specimens were submitted to shear bond testing, while the others were subjected to mechanical cycling. ANOVA showed that mechanical cycling did not have a significant influence on bond strength (P = 0.9244), while surface conditioning of the brackets did (P = 0.0001). Tukey's test results were similar for mechanical cycling, and indicated that only Group 3 significantly improved the resin bond to the brackets; however, this group also demonstrated the highest percentage of enamel failure.

  11. Effect of age on extrastriatal dopamine D2 receptor availability

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.J.; Volkow, N.D.; Fowler, J.S. [Brookhaven National Lab., Upton, NY (United States)]|[SUNY, Stony Brook, NY (United States)

    1996-05-01

    It is known that dopamine (DA) D2 receptor availability in basal ganglia decreases with age. This study was done to assess the effects of age on extrastriatal DA D2 receptors. DA D2 receptor availability was evaluated in 42 healthy male subjects (age mean 41 {plus_minus} 16, range 21 -86 year old) using positron emission tomography (PET) and [C-11]raclopride. DA D2 receptor availability was measured using the ratio of the distribution volume in the region of interest (caudate, putamen, thalamus, frontal, occipital cortices, temporal insula, cingulate and orbitofrontal gyri) to that in the cerebellum which is a function of B{sub max.}/K{sub d}. Pearson product-moment correlation was used to evaluate the correlation between age and D2 receptor availability. DA D2 receptor availability in putamen (r {le} 0.0001), caudate (r {le} 0.0002), thalamus (r {le} 0.03), and temporal insula (r {le} 0.01) were significantly correlated with age. The decrements in D2 receptors with age were lower in extrastriatal than in striatal regions and corresponded to a decrease of 4.7% per decade in caudate, 6.2% in putamen, 2.1% in thalamus and 2.5% in temporal insula. This study documents age related decrement of DA D2 receptor availability in striatal and extrastriatal regions.

  12. Effect of NCAM on aged-related deterioration in vision.

    Science.gov (United States)

    Luke, Margaret Po-Shan; LeVatte, Terry L; O'Reilly, Amanda M; Smith, Benjamin J; Tremblay, François; Brown, Richard E; Clarke, David B

    2016-05-01

    The neural cell adhesion molecule (NCAM) is involved in developmental processes and age-associated cognitive decline; however, little is known concerning the effects of NCAM in the visual system during aging. Using anatomical, electrophysiological, and behavioral assays, we analyzed age-related changes in visual function of NCAM deficient (-/-) and wild-type mice. Anatomical analyses indicated that aging NCAM -/- mice had fewer retinal ganglion cells, thinner retinas, and fewer photoreceptor cell layers than age-matched controls. Electroretinogram testing of retinal function in young adult NCAM -/- mice showed a 2-fold increase in a- and b-wave amplitude compared with wild-type mice, but the retinal activity dropped dramatically to control levels when the animals reached 10 months. In behavioral tasks, NCAM -/- mice had no visual pattern discrimination ability and showed premature loss of vision as they aged. Together, these findings demonstrate that NCAM plays significant roles in the adult visual system in establishing normal retinal anatomy, physiology and function, and in maintaining vision during aging.

  13. Neural protein synthesis during aging: effects on plasticity and memory

    Directory of Open Access Journals (Sweden)

    Lesley A Schimanski

    2010-08-01

    Full Text Available During aging, many experience a decline in cognitive function that includes memory loss. The encoding of long-term memories depends on new protein synthesis, and this is also reduced during aging. Thus, it is possible that changes in the regulation of protein synthesis contribute to the memory impairments observed in older animals. Several lines of evidence support this hypothesis. For instance, protein synthesis is required for a longer period following learning to establish long-term memory in aged rodents. Also, under some conditions, synaptic activity or pharmacological activation can induce de novo protein synthesis and lasting changes in synaptic transmission in aged, but not young, rodents; the opposite results can be observed in other conditions. These changes in plasticity likely play a role in manifesting the altered place field properties observed in awake and behaving aged rats. Thus, the collective evidence suggests a link between memory loss and the regulation of protein synthesis in senescence. In fact, pharmaceuticals that target the signaling pathways required for induction of protein synthesis have been shown to improve memory, synaptic plasticity, and place cell properties in aged animals. We suggest that a better understanding of the mechanisms that lead to different protein expression patterns in the neural circuits that change as a function of age will enable the development of more effective therapeutic treatments for memory loss.

  14. Leveraging this Golden Age of Remote Sensing and Modeling of Terrestrial Hydrology to Understand Water Cycling in the Water Availability Grand Challenge for North America

    Science.gov (United States)

    Painter, T. H.; Famiglietti, J. S.; Stephens, G. L.

    2016-12-01

    We live in a time of increasing strains on our global fresh water availability due to increasing population, warming climate, changes in precipitation, and extensive depletion of groundwater supplies. At the same time, we have seen enormous growth in capabilities to remotely sense the regional to global water cycle and model complex systems with physically based frameworks. The GEWEX Water Availability Grand Challenge for North America is poised to leverage this convergence of remote sensing and modeling capabilities to answer fundamental questions on the water cycle. In particular, we envision an experiment that targets the complex and resource-critical Western US from California to just into the Great Plains, constraining physically-based hydrologic modeling with the US and international remote sensing capabilities. In particular, the last decade has seen the implementation or soon-to-be launch of water cycle missions such as GRACE and GRACE-FO for groundwater, SMAP for soil moisture, GPM for precipitation, SWOT for terrestrial surface water, and the Airborne Snow Observatory for snowpack. With the advent of convection-resolving mesoscale climate and water cycle modeling (e.g. WRF, WRF-Hydro) and mesoscale models capable of quantitative assimilation of remotely sensed data (e.g. the JPL Western States Water Mission), we can now begin to test hypotheses on the nature and changes in the water cycle of the Western US from a physical standpoint. In turn, by fusing water cycle science, water management, and ecosystem management while addressing these hypotheses, this golden age of remote sensing and modeling can bring all fields into a markedly less uncertain state of present knowledge and decadal scale forecasts.

  15. Effect of Antioxidants Supplementation on Aging and Longevity

    Directory of Open Access Journals (Sweden)

    Izabela Sadowska-Bartosz

    2014-01-01

    Full Text Available If aging is due to or contributed by free radical reactions, as postulated by the free radical theory of aging, lifespan of organisms should be extended by administration of exogenous antioxidants. This paper reviews data on model organisms concerning the effects of exogenous antioxidants (antioxidant vitamins, lipoic acid, coenzyme Q, melatonin, resveratrol, curcumin, other polyphenols, and synthetic antioxidants including antioxidant nanoparticles on the lifespan of model organisms. Mechanisms of effects of antioxidants, often due to indirect antioxidant action or to action not related to the antioxidant properties of the compounds administered, are discussed. The legitimacy of antioxidant supplementation in human is considered.

  16. Effect of Antioxidants Supplementation on Aging and Longevity

    Science.gov (United States)

    Bartosz, Grzegorz

    2014-01-01

    If aging is due to or contributed by free radical reactions, as postulated by the free radical theory of aging, lifespan of organisms should be extended by administration of exogenous antioxidants. This paper reviews data on model organisms concerning the effects of exogenous antioxidants (antioxidant vitamins, lipoic acid, coenzyme Q, melatonin, resveratrol, curcumin, other polyphenols, and synthetic antioxidants including antioxidant nanoparticles) on the lifespan of model organisms. Mechanisms of effects of antioxidants, often due to indirect antioxidant action or to action not related to the antioxidant properties of the compounds administered, are discussed. The legitimacy of antioxidant supplementation in human is considered. PMID:24783202

  17. Effects of Resveratrol on Daily Rhythms of Locomotor Activity and Body Temperature in Young and Aged Grey Mouse Lemurs

    Directory of Open Access Journals (Sweden)

    Fabien Pifferi

    2013-01-01

    Full Text Available In several species, resveratrol, a polyphenolic compound, activates sirtuin proteins implicated in the regulation of energy balance and biological clock processes. To demonstrate the effect of resveratrol on clock function in an aged primate, young and aged mouse lemurs (Microcebus murinus were studied over a 4-week dietary supplementation with resveratrol. Spontaneous locomotor activity and daily variations in body temperature were continuously recorded. Reduction in locomotor activity onset and changes in body temperature rhythm in resveratrol-supplemented aged animals suggest an improved synchronisation on the light-dark cycle. Resveratrol could be a good candidate to restore the circadian rhythms in the elderly.

  18. Reinforcing effects of cigarette advertising on under-age smoking.

    Science.gov (United States)

    Aitken, P P; Eadie, D R

    1990-03-01

    Interviews were conducted with 848 Glasgow children aged between 11 and 14 years. There were consistent differences between smokers and non-smokers. Smokers tended to be more adept at recalling, recognizing and identifying cigarette advertisements. This suggests they tend to pay more attention to cigarette advertising. Smokers also tended to be generally more appreciative of cigarette advertising. Moreover, this greater awareness and appreciation of cigarette advertising was independent of other important predictors of under-age smoking, such as smoking by peers, siblings and parents. These findings, taken in conjunction with previous research, indicate that cigarette advertising is reinforcing under-age smoking. The smokers showed an enhanced or heightened preference for Kensitas Club, the brand favoured by adults. This is consistent with previous research indicating that promotional devices which help determine and reinforce adult cigarette brand preferences have an even greater effect on under-age smokers.

  19. FES cycling.

    Science.gov (United States)

    Newham, D J; Donaldson, N de N

    2007-01-01

    Spinal cord injury (SCI) leads to a partial or complete disruption of motor, sensory, and autonomic nerve pathways below the level of the lesion. In paraplegic patients, functional electrical stimulation (FES) was originally widely considered as a means to restore walking function but this was proved technically very difficult because of the numerous degrees of freedom involved in walking. FES cycling was developed for people with SCI and has the advantages that cycling can be maintained for reasonably long periods in trained muscles and the risk of falls is low. In the article, we review research findings relevant to the successful application of FES cycling including the effects on muscle size, strength and function, and the cardiovascular and bone changes. We also describe important practical considerations in FES cycling regarding the application of surface electrodes, training and setting up the stimulator limitations, implanted stimulators and FES cycling including FES cycling in groups and other FES exercises such as FES rowing.

  20. The effect of normal aging and age-related macular degeneration on perceptual learning

    Science.gov (United States)

    Astle, Andrew T.; Blighe, Alan J.; Webb, Ben S.; McGraw, Paul V.

    2015-01-01

    We investigated whether perceptual learning could be used to improve peripheral word identification speed. The relationship between the magnitude of learning and age was established in normal participants to determine whether perceptual learning effects are age invariant. We then investigated whether training could lead to improvements in patients with age-related macular degeneration (AMD). Twenty-eight participants with normal vision and five participants with AMD trained on a word identification task. They were required to identify three-letter words, presented 10° from fixation. To standardize crowding across each of the letters that made up the word, words were flanked laterally by randomly chosen letters. Word identification performance was measured psychophysically using a staircase procedure. Significant improvements in peripheral word identification speed were demonstrated following training (71% ± 18%). Initial task performance was correlated with age, with older participants having poorer performance. However, older adults learned more rapidly such that, following training, they reached the same level of performance as their younger counterparts. As a function of number of trials completed, patients with AMD learned at an equivalent rate as age-matched participants with normal vision. Improvements in word identification speed were maintained at least 6 months after training. We have demonstrated that temporal aspects of word recognition can be improved in peripheral vision with training across a range of ages and these learned improvements are relatively enduring. However, training targeted at other bottlenecks to peripheral reading ability, such as visual crowding, may need to be incorporated to optimize this approach. PMID:26605694

  1. Life-Cycle Costing of Food Waste Management in Denmark: Importance of Indirect Effects.

    Science.gov (United States)

    Martinez-Sanchez, Veronica; Tonini, Davide; Møller, Flemming; Astrup, Thomas Fruergaard

    2016-04-19

    Prevention has been suggested as the preferred food waste management solution compared to alternatives such as conversion to animal fodder or to energy. In this study we used societal life-cycle costing, as a welfare economic assessment, and environmental life-cycle costing, as a financial assessment combined with life-cycle assessment, to evaluate food waste management. Both life-cycle costing assessments included direct and indirect effects. The latter are related to income effects, accounting for the marginal consumption induced when alternative scenarios lead to different household expenses, and the land-use-changes effect, associated with food production. The results highlighted that prevention, while providing the highest welfare gains as more services/goods could be consumed with the same income, could also incur the highest environmental impacts if the monetary savings from unpurchased food commodities were spent on goods/services with a more environmentally damaging production than that of the (prevented) food. This was not the case when savings were used, e.g., for health care, education, and insurances. This study demonstrates that income effects, although uncertain, should be included whenever alternative scenarios incur different financial costs. Furthermore, it highlights that food prevention measures should not only demote the purchase of unconsumed food but also promote a low-impact use of the savings generated.

  2. Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions...

  3. Effects of the antithyroid agent propylthiouracil in a partial life cycle assay with zebrafish.

    NARCIS (Netherlands)

    Ven, Leo T M van der; Brandhof, Evert-Jan van den; Vos, José H; Power, Deborah M; Wester, Piet W

    2006-01-01

    Some ubiquitous pollutants of the aquatic environment, such as PCBs or other polyhalogenated aromatic hydrocarbons, may disrupt the thyroid hormone system. In a partial life cycle assay with zebrafish (Danio rerio), we studied the effects of the reference compound propylthiouracil (PTU) on reproduct

  4. 10 CFR 435.306 - Selecting a life cycle effective proposed building design.

    Science.gov (United States)

    2010-01-01

    ... between or among proposed building designs which comply with the applicable energy consumption goal under... 10 Energy 3 2010-01-01 2010-01-01 false Selecting a life cycle effective proposed building design... FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for...

  5. Effect of mechanical cycling on the flexural strength of densely sintered ceramics

    NARCIS (Netherlands)

    Itinoche, Koiti Marco; Ozcan, Mudu; Bottino, Marco Antonio; Oyafuso, Denise

    2006-01-01

    Objectives. The aim of this study was to evaluate the effect of mechanical cycling on the biaxial flexural strength of two densely sintered ceramic materials. Methods. Disc shaped zirconia (In-Ceram Zirconia) and high alumina (Procera AllCeram) ceramic specimens (diameter: 15 min and thickness: 1.2

  6. The effect of skin temperature on performance during a 7.5-km cycling time trial

    NARCIS (Netherlands)

    Levels, K.; Koning, J.J. de; Foster, C.; Daanen, H.A.M.

    2012-01-01

    Aerobic exercise performance is seriously compromised in the heat. Possibly, a high skin temperature causes a rating of perceived exertion (RPE)-mediated decrease in exercise intensity. The purpose of this study was to determine the effect of skin temperature on power output during a 7.5-km cycling

  7. Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling: Interactions and Feedbacks

    Science.gov (United States)

    Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions...

  8. Expectancy and the Menstrual Cycle: Effects on Performance and Self-Perception.

    Science.gov (United States)

    Altenhaus, Amy L.

    The impact of false information concerning the effect of the menstrual cycle on test performance and subjects' perception of the adequacy of that performance were investigated. Women (N=65) were studied either during the premenstrual or midcycle phase. Subjects were given one of three interpretations: (1) they should do well because of their…

  9. Mechanical and thermal cycling effects on the flexural strength of glass ceramics fused to titanium

    NARCIS (Netherlands)

    Vasquez, Vanessa; Ozcan, Mutlu; Nishioka, Renato; Souza, Rodrigo; Mesquita, Alfredo; Pavanelli, Carlos

    2008-01-01

    This study evaluated the effects of mechanical and thermal cycling on the flexural strength (ISO 9693) of three brands of ceramics fused to commercially pure titanium (cpTi). Metallic frameworks of 25 x 3 x 0.5 mm dimensions (N = 84) were cast in cpTi, followed by 150-mu m aluminum oxide airborne pa

  10. The effect of ambient temperature on gross-efficiency in cycling

    NARCIS (Netherlands)

    Hettinga, F.J.; Koning, J.J. de; Vrijer, A. de; Wüst, R.C.I.; Daanen, H.A.M.; Foster, C.

    2007-01-01

    Time-trial performance deteriorates in the heat. This might potentially be the result of a temperature-induced decrease in gross-efficiency (GE). The effect of high ambient temperature on GE during cycling will be studied, with the intent of determining if a heat-induced change in GE could account f

  11. The effect of temperature cycling on the DC conductivity of polyethylene

    DEFF Research Database (Denmark)

    Khalil, M.S.; Henriksen, Mogens; Henk, Peter O

    1992-01-01

    The effect of temperature cycling between 40°C and 80°C during combined temperature and electric field conditioning on the DC conductivity of LDPE (low-density polyethylene) has been studied and compared with DC conductivity results using a constant temperature of 80°C and an identical sample under...

  12. Effects of listening to music, and of using a handheld and handsfree telephone on cycling behaviour

    NARCIS (Netherlands)

    De Waard, D.; Edlinger, K.M.; Brookhuis, K.A.

    2011-01-01

    The effects of listening to music on cycling behaviour were evaluated. Twenty-five participants completed a track on a bicycle while listening to music with two standard earbuds, with one earbud, and with two in-earbuds. Conditions with high tempo music and loud volume were also included in the expe

  13. Mechanical and thermal cycling effects on the flexural strength of glass ceramics fused to titanium

    NARCIS (Netherlands)

    Vasquez, Vanessa; Ozcan, Mutlu; Nishioka, Renato; Souza, Rodrigo; Mesquita, Alfredo; Pavanelli, Carlos

    This study evaluated the effects of mechanical and thermal cycling on the flexural strength (ISO 9693) of three brands of ceramics fused to commercially pure titanium (cpTi). Metallic frameworks of 25 x 3 x 0.5 mm dimensions (N = 84) were cast in cpTi, followed by 150-mu m aluminum oxide airborne

  14. Expectancy and the Menstrual Cycle: Effects on Performance and Self-Perception.

    Science.gov (United States)

    Altenhaus, Amy L.

    The impact of false information concerning the effect of the menstrual cycle on test performance and subjects' perception of the adequacy of that performance were investigated. Women (N=65) were studied either during the premenstrual or midcycle phase. Subjects were given one of three interpretations: (1) they should do well because of their…

  15. Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

    Directory of Open Access Journals (Sweden)

    Odilon Abrahin

    Full Text Available ABSTRACT Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD. This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed®, SciELO® and LILACS®. Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

  16. The effect of the reversed tricarboxylic acid cycle on the (13)C contents of bacterial lipids

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Meer, M.T.J. van der; Schouten, S.

    1998-01-01

    Free and esterified lipids of a green sulfur bacterium, Chlorobium limicola, and a purple sulfur bacterium, Thiocapsa roseopersicina, were investigated to examine the effect of the reversed tricarboxylic acid cycle on the 13C contents of their lipids. The lipids of C. limicola are 2 to 16 enriched

  17. Effect of cure cycle on enthalpy relaxation and post shrinkage in neat epoxy and epoxy composites

    DEFF Research Database (Denmark)

    Jensen, Martin; Jakobsen, Johnny

    2016-01-01

    The effect of cure cycle on enthalpy relaxation and warpage is studied for both neat epoxy and glass/epoxy composites. An approach for determining the enthalpy relaxation in the matrix of composite materials combining modulated differential scanning calorimetry and thermogravimetry is presented...

  18. Effects of common germ-line genetic variation in cell cycle genes on ovarian cancer survival

    DEFF Research Database (Denmark)

    Song, H.; Hogdall, E.; Ramus, S.J.

    2008-01-01

    PURPOSE: Somatic alterations have been shown to correlate with ovarian cancer prognosis and survival, but less is known about the effects on survival of common inherited genetic variation. Of particular interest are genes involved in cell cycle pathways, which regulate cell division and could pla...

  19. Effect of heat and heat acclimatization on cycling time trial performance and pacing

    DEFF Research Database (Denmark)

    Racinais, Sebastien; Périard, Julien D; Karlsen, Anders;

    2015-01-01

    PURPOSE: To determine the effects of heat-acclimatization on performance and pacing during outdoor cycling time-trials (TT, 43.4km) in the heat. METHODS: Nine cyclists performed 3 TTs in hot ambient conditions (TTH, ∼37ºC) on the first (TTH-1), sixth (TTH-2) and fourteenth (TTH-3) days of trainin...

  20. Effects of the antithyroid agent propylthiouracil in a partial life cycle assay with zebrafish.

    NARCIS (Netherlands)

    Ven, Leo T M van der; Brandhof, Evert-Jan van den; Vos, José H; Power, Deborah M; Wester, Piet W

    2006-01-01

    Some ubiquitous pollutants of the aquatic environment, such as PCBs or other polyhalogenated aromatic hydrocarbons, may disrupt the thyroid hormone system. In a partial life cycle assay with zebrafish (Danio rerio), we studied the effects of the reference compound propylthiouracil (PTU) on

  1. Relationships between solar activity and climate change. [sunspot cycle effects on lower atmosphere

    Science.gov (United States)

    Roberts, W. O.

    1974-01-01

    Recurrent droughts are related to the double sunspot cycle. It is suggested that high solar activity generally increases meridional circulations and blocking patterns at high and intermediate latitudes, especially in winter. This effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

  2. Effects of diet and exposure to hindlimb suspension on estrous cycling in Sprague-Dawley rats

    Science.gov (United States)

    Tou, Janet C L.; Grindeland, Richard E.; Wade, Charles E.

    2004-01-01

    Various factors can disrupt the female reproductive cycle resulting in subfertility. The primary objective of this study was to determine whether physiological changes associated with exposure to hypogravity disrupt reproductive cycles. The hindlimb suspension (HLS) model was used to simulate the major physiological effects of hypogravity in female Sprague-Dawley rats. Also, to determine whether diet may influence reproductive results, rats were fed purified American Institute of Nutrition (AIN)-93G or chow diet. Rats (n = 9-11/group) subjected to HLS had lengthened estrous cycles due to prolonged diestrus, indicating hypoestrogenism. Interestingly, HLS rats fed AIN-93G but not chow diet had significantly reduced time spent in estrus and decreased plasma estradiol. Attenuation of hypoestrogenism in the chow-fed rats suggested that diet provided an exogenous source of estrogen. The mechanism involved in the disruption of estrous cycling remains to be determined. HLS increased urinary corticosterone (CORT) levels during the initial 4 days of HLS, suggesting that physiological responses to acute stress may be a potential mechanism in the disruption of estrous cycles. Higher basal urinary CORT was observed in rats fed chow vs. AIN-93G diet. HLS resulted in increased urinary CORT. However, two-way ANOVA indicated a significant HLS effect (P diet effect on urinary CORT levels, suggesting that estrogenic activity associated with the chow diet did not enhance the stress response. The results of this study indicate that HLS, diet, and the combination of HLS and diet influence estrous cycling. This has important implications for future reproductive success in the hypogravity environment of space.

  3. Freeze-Thaw Cycles Effects on Soil Compaction in a Clay Loam

    Science.gov (United States)

    Jabro, J.; Evans, R.; Iversen, W.

    2012-04-01

    Inappropriate soil management practices and heavier farm machinery and equipment have led to an increase in soil compaction in the last two decades prompting increased global concern regarding the impact of soil compaction on crop production and soil quality in modern mechanized agriculture. A 3-yr comprehensive study was established to evaluate the dynamic of freeze-thaw cycles on soil compaction in a clay loam soil. Plots of frozen soils were compared with plots where soils were prevented from freezing with electrically heated blankets commonly used on concrete. Results showed that frequent freeze-thaw cycles over the winter alleviated a majority of soil compaction at the 0 - 20 cm depth. Soil penetration resistance in compacted soils was reduced by 73 and 68% over the winter at the 0 - 10 and 10 - 20 cm depths, respectively, due to dynamic effects of freeze-thaw cycles on soil structure and particles configuration. In unfrozen compacted soils, the penetration resistance was also reduced by 50 and 60% over winter at the 0 - 10 and 10 - 20 cm depths, respectively, due to the biology of soil, microbial activity, and disruptive effects of shrink-swell cycles. These results have demonstrated of how repeated freeze-thaw cycles can alleviate soil compaction, alter soil physical quality and create optimal soil conditions required for profitable growth of agricultural crops. The results from this study will save growers considerable time, money and energy currently required to alleviate soil compaction using other methods such as sub-soiling and deep tillage. We believe that Mother Nature provides ways to reverse soil compaction and improve soil structure and aggregation through the dynamic of freeze-thaw cycles that soils in Montana and other parts of the country go through each year. We concluded that the Mother Nature is the most effective and cheapest way to alleviate soil compaction.

  4. Effects of aging on thyroidal function and proliferation.

    Science.gov (United States)

    da Costa, V M Corrêa; Rosenthal, D

    2008-07-01

    The endocrine system is as affected by aging as are other systems. The effect of aging on the hypothalamus-pituitary-thyroid function is still controversial. Human aging was reported as associated with a decrease in thyrotropin (TSH) secretion, but increased TSH levels in relatively healthy elders are also reported. The main point discussed is whether this increase in the immunoreactive TSH of aged subjects, and related changes in thyroid function, are "physiologic" consequences of aging on the hypothalamus-pituitary-thyroid axis or are induced by non-thyroid illnesses and/or drug use, frequent in the elderly. There are strong evidences of decreased hypothalamus-pituitary-thyroid axis activity as well as decreased thyroxine metabolism (5'-deiodination) in humans, and other mammals. For now, we must consider that the hypothalamus-pituitary-thyroid axis is affected at all three levels by normal aging, and the mild state of "total" hypothyroidism during aging is completed by a reduced response of target cells/tissues to thyroid hormones. Despite the decreased response of the old rat thyroid to TSH there is no decrease in the glands mass. Ras proteins are involved in the transduction of growth factor signals by surface receptors, in thyroid as well as in other tissues, and are key components of downstream signaling through several pathways. Ras activation of Raf, and of extracellular-signal-regulated kinases (ERK) is an important signaling pathway for many Ras effects. Very little is known about the modulation of Ras expression in the aging thyroid. We detected an increase in Ras expression in thyroids of old rats, but the signal transduction by pERK was decreased, suggesting that another RAS-signaling pathway could be activated and responsible for the maintenance of the thyroid volume.

  5. Can aging in place be cost effective? A systematic review.

    Science.gov (United States)

    Graybill, Erin M; McMeekin, Peter; Wildman, John

    2014-01-01

    To systematically review cost, cost-minimization and cost-effectiveness studies for assisted living technologies (ALTs) that specifically enable older people to 'age in place' and highlight what further research is needed to inform decisions regarding aging in place. People aged 65+ and their live-in carers (where applicable), using an ALT to age in place at home opposed to a community-dwelling arrangement. Studies were identified using a predefined search strategy on two key economic and cost evaluation databases NHS EED, HEED. Studies were assessed using methods recommended by the Campbell and Cochrane Economic Methods Group and presented in a narrative synthesis style. Eight eligible studies were identified from North America spread over a diverse geographical range. The majority of studies reported the ALT intervention group as having lower resource use costs than the control group; though the low methodological quality and heterogeneity of the individual costs and outcomes reported across studies must be considered. The studies suggest that in some cases ALTs may reduce costs, though little data were identified and what there were was of poor quality. Methods to capture quality of life gains were not used, therefore potential effects on health and wellbeing may be missed. Further research is required using newer developments such as the capabilities approach. High quality studies assessing the cost-effectiveness of ALTs for ageing in place are required before robust conclusion on their use can be drawn.

  6. Can aging in place be cost effective? A systematic review.

    Directory of Open Access Journals (Sweden)

    Erin M Graybill

    Full Text Available PURPOSE OF THE STUDY: To systematically review cost, cost-minimization and cost-effectiveness studies for assisted living technologies (ALTs that specifically enable older people to 'age in place' and highlight what further research is needed to inform decisions regarding aging in place. DESIGN: People aged 65+ and their live-in carers (where applicable, using an ALT to age in place at home opposed to a community-dwelling arrangement. METHODS: Studies were identified using a predefined search strategy on two key economic and cost evaluation databases NHS EED, HEED. Studies were assessed using methods recommended by the Campbell and Cochrane Economic Methods Group and presented in a narrative synthesis style. RESULTS: Eight eligible studies were identified from North America spread over a diverse geographical range. The majority of studies reported the ALT intervention group as having lower resource use costs than the control group; though the low methodological quality and heterogeneity of the individual costs and outcomes reported across studies must be considered. IMPLICATIONS: The studies suggest that in some cases ALTs may reduce costs, though little data were identified and what there were was of poor quality. Methods to capture quality of life gains were not used, therefore potential effects on health and wellbeing may be missed. Further research is required using newer developments such as the capabilities approach. High quality studies assessing the cost-effectiveness of ALTs for ageing in place are required before robust conclusion on their use can be drawn.

  7. Selective control of attention supports the positivity effect in aging.

    Directory of Open Access Journals (Sweden)

    Laura K Sasse

    Full Text Available There is emerging evidence for a positivity effect in healthy aging, which describes an age-specific increased focus on positive compared to negative information. Life-span researchers have attributed this effect to the selective allocation of cognitive resources in the service of prioritized emotional goals. We explored the basic principles of this assumption by assessing selective attention and memory for visual stimuli, differing in emotional content and self-relevance, in young and old participants. To specifically address the impact of cognitive control, voluntary attentional selection during the presentation of multiple-item displays was analyzed and linked to participants' general ability of cognitive control. Results revealed a positivity effect in older adults' selective attention and memory, which was particularly pronounced for self-relevant stimuli. Focusing on positive and ignoring negative information was most evident in older participants with a generally higher ability to exert top-down control during visual search. Our findings highlight the role of controlled selectivity in the occurrence of a positivity effect in aging. Since the effect has been related to well-being in later life, we suggest that the ability to selectively allocate top-down control might represent a resilience factor for emotional health in aging.

  8. Effect of menstrual cycle phase on background parenchymal uptake on molecular breast imaging

    Science.gov (United States)

    Hruska, Carrie B.; Conners, Amy Lynn; Vachon, Celine M.; O’Connor, Michael K.; Shuster, Lynne T.; Bartley, Adam C.; Rhodes, Deborah J.

    2015-01-01

    Rationale and Objectives The level of Tc-99m sestamibi uptake within normal fibroglandular tissue on molecular breast imaging (MBI), termed background parenchymal uptake (BPU), has been anecdotally observed to fluctuate with menstrual cycle. Our objective was to assess the impact of menstrual cycle phase on BPU appearance. Materials and Methods Premenopausal volunteers who reported regular menstrual cycles and no exogenous hormone use were recruited to undergo serial MBI exams during the follicular and luteal phase. A study radiologist, blinded to cycle phase, categorized BPU as either photopenic, minimal-mild, moderate, or marked. Change in BPU with cycle phase was determined as well as correlations of BPU with mammographic density and hormone levels. Results Among 42 analyzable participants, high BPU (moderate or marked) was observed more often in luteal phase compared to follicular (p = 0.016). BPU did not change with phase in 30 of 42 (71%) and increased in the luteal phase compared to follicular in 12 (29%). High BPU was more frequent in dense breasts compared to non-dense breasts at both the luteal phase (58% [15/26] vs. 13% [2/16], p= 0.004) and follicular phase (35% [9/26] vs. 6% [1/16], p=0.061). Spearman’s correlation coefficients did not show any correlation of BPU with hormone levels measured at either cycle phase, and suggested a weak correlation between change in BPU and changes in estrone and estradiol between phases. Conclusion We observed variable effects of menstrual cycle on BPU among our cohort of premenopausal women, however, when high BPU was observed, it was most frequently seen during the luteal phase compared to follicular phase, and in women with dense breasts compared to non-dense breasts. PMID:26112057

  9. The effects of prior cycling and a successive run on respiratory muscle performance in triathletes.

    Science.gov (United States)

    Boussana, A; Galy, O; Hue, O; Matecki, S; Varray, A; Ramonatxo, M; Le Gallais, D

    2003-01-01

    The aim of the present study was to compare the effects of prior cycling and a successive run on respiratory muscle performance during a cycle-run succession as performed in the triathlon. We hypothesized that despite the moderate intensity of exercise and the absence of exhaustion, the crouched cycling position would induce a decrease in respiratory muscle performance that would be reversed by the successive vertical run position. Ten male triathletes (22.6 +/- 1.1 yr) performed a four-trial protocol: (1) an incremental cycle test to assess maximal oxygen uptake (VO2max), (2) 20 min of cycling (C), (3) 20 min of running (R), and (4) 20 min of cycling followed by 20 min of running (C-R). Trials 2, 3 and 4 were performed at the same metabolic intensity, i. e., 75 % of VO2max. Respiratory muscle force was assessed by measuring maximal expiratory (P(Emax)) and inspiratory (P(Imax)) pressures from the functional residual capacity (FRC) before and 10 min after C, R, and C-R. Respiratory muscle endurance was assessed one day before and 30 min after C, R, and C-R, by measuring the time limit (T(lim)), which corresponds to the length of time a respiratory load can be sustained before the process of fatigue develops sufficiently to cause task failure. The results showed a similar significant decrease in P(Imax) (132.4 +/- 4.9 versus 125.7 +/- 5.6 cm H2O, p 0.05). We concluded that moderate intensity exercise not performed to exhaustion induced a decrease in respiratory muscle performance. Moreover, the respiratory muscle fatigue induced by prior cycling was maintained, and neither reversed nor worsened, by the successive run.

  10. Effects of Space Weather on Biomedical Parameters during the Solar Activity Cycles 23-24.

    Science.gov (United States)

    Ragul'skaya, M V; Rudenchik, E A; Chibisov, S M; Gromozova, E N

    2015-06-01

    The results of long-term (1998-2012) biomedical monitoring of the biotropic effects of space weather are discussed. A drastic change in statistical distribution parameters in the middle of 2005 was revealed that did not conform to usual sinusoidal distribution of the biomedical data reflecting changes in the number of solar spots over a solar activity cycle. The dynamics of space weather of 2001-2012 is analyzed. The authors hypothesize that the actual change in statistical distributions corresponds to the adaptation reaction of the biosphere to nonstandard geophysical characteristics of the 24th solar activity cycle and the probable long-term decrease in solar activity up to 2067.

  11. Effects of recrystallization on the low cycle fatigue behavior of directionally solidified superalloy DZ40M

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yang; WANG Lei; LI Hongyun; YU Teng; LIU Yang

    2008-01-01

    The effects of recrystallization on low cycle fatigue behavior were investigated on directionally solidified Co-base superalloy DZAOM.Optical microscopy and SEM were used to examine the mierostructure and fracture surface of the specimens.The mechanical testing results demonstrated that the low cycle fatigue property of DZ40M significantly decreased with the partial reerystallization.Fatigue cracks initiate near the carbides and the grain boundaries with slip-bands.Both the fatigue crack initiation and propagation can be accelerated with the occurrences of recrystallized grain boundaries.

  12. Effects of Thermal Cycling on Control and Irradiated EPC 2nd Generation GaN FETs

    Science.gov (United States)

    Patterson, Richard L.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

    2013-01-01

    The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling in order to address their reliability for use in space missions. Results of the experimental work are presented and discussed.

  13. The effect of thermal cycle on joint of Ti/stainless steel phase transformation diffusion bonding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of thermal cycle parameters on the tensile strength and fracture characteristics of phase transformation diffusion bonding(PTDB) joint of titanium and stainless steel (Ti/SS) were studied in this paper. With the maximum cyclic temperature of 1173~1223K, the minimum cyclic temperature of 1073~1093K, the heating velocity of 30~50K/s, the cooling velocity of 15~20K/s , the cycle numbers of 15~20 and bonding pressure is 13MPa, the tensile strength of joint is more than 380MPa, exceeding 80% of that of Ti.

  14. Reversible cell cycle inhibition and premature aging features imposed by conditional expression of p16Ink4a

    Science.gov (United States)

    Boquoi, Amelie; Arora, Sanjeevani; Chen, Tina; Litwin, Sam; Koh, James; Enders, Greg H

    2015-01-01

    The cyclin-dependent kinase (Cdk) inhibitor p16Ink4a (p16) is a canonical mediator of cellular senescence and accumulates in aging tissues, where it constrains proliferation of some progenitor cells. However, whether p16 induction in tissues is sufficient to inhibit cell proliferation, mediate senescence, and/or impose aging features has remained unclear. To address these issues, we generated transgenic mice that permit conditional p16 expression. Broad induction at weaning inhibited proliferation of intestinal transit-amplifying and Lgr5+ stem cells and rapidly imposed features of aging, including hair loss, skin wrinkling, reduced body weight and subcutaneous fat, an increased myeloid fraction in peripheral blood, poor dentition, and cataracts. Aging features were observed with multiple combinations of p16 transgenes and transactivators and were largely abrogated by a germline Cdk4 R24C mutation, confirming that they reflect Cdk inhibition. Senescence markers were not found, and de-induction of p16, even after weeks of sustained expression, allowed rapid recovery of intestinal cell proliferation and reversal of aging features in most mice. These results suggest that p16-mediated inhibition of Cdk activity is sufficient to inhibit cell proliferation and impose aging features in somatic tissues of mammals and that at least some of these aging features are reversible. PMID:25481981

  15. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    Science.gov (United States)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  16. An 'other-race' effect in age estimation from faces.

    Science.gov (United States)

    Dehon, H; Brédart, S

    2001-01-01

    Previous studies have shown that, in person-recognition tasks, people perform better for faces belonging to their own race than for those belonging to another race. Recently, however, this 'other-race' effect has also been found in a sex-discrimination task (O'Toole et al, 1996 Perception 25 669-676). In the present study, we investigated whether this finding extends to age perception. Caucasian and African participants were asked to estimate the age of Caucasian and African faces. The main result of this experiment was a significant 'race of subject' x 'race of face' interaction showing that Caucasian participants performed better at evaluating Caucasian faces than African faces. However, African participants performed equally with both type of faces. This result is explained by the Africans' time of residence in Belgium. The implication of this 'other-race' effect for age estimation is discussed with respect to eyewitness reports.

  17. Gender-dependent effects of aging on the kidney

    Directory of Open Access Journals (Sweden)

    A.L. Gava

    2011-09-01

    Full Text Available It is well known that the kidney plays an important role in the development of cardiovascular diseases such as hypertension. The normal aging process leads to changes in kidney morphology, hemodynamics and function, which increase the incidence of cardiovascular events in the elderly population. These disturbances are influenced by several factors, including gender. In general, females are protected by the effects of estrogens on the cardiorenal system. Several studies have demonstrated the beneficial effects of estrogens on renal function in the elderly; however, the relationships between androgens and kidney health during one’s lifetime are not well understood. Sex steroids have many complex actions, and the decline in their levels during aging clearly influences kidney function, decreases the renal reserve and facilitates the development of cardiovascular disorders. Therefore, in this review, we discuss the cellular, biochemical, and molecular mechanisms by which sex hormones may influence renal function during the aging process.

  18. Effect of concurrent training, flexible nonlinear periodization, and maximal-effort cycling on strength and power.

    Science.gov (United States)

    McNamara, John M; Stearne, David J

    2013-06-01

    Although there is considerable research on concurrent training, none has integrated flexible nonlinear periodization and maximal-effort cycling in the same design. The purpose of this investigation was to test outcome measures of strength and power using a pretest-posttest randomized groups design. A strength and endurance (SE) group was compared with a strength, endurance, and maximal-effort cycling (SEC) group. Both groups used a flexible nonlinear periodization design. Thirteen male and 7 female students (mean ± SD: age, 22.5 ± 4.1 years; height, 173.5 ± 12.4 cm; weight, 79.4 ± 20.2 kg; strength training experience, 2.4 ± 2.2 years) participated in this study. Groups were not matched for age, height, weight, strength training experience, or sex, but were randomly assigned to an SE (n = 10) or SEC (n = 10) group. All training was completed within 45 minutes, twice per week (Monday and Wednesday), over 12 consecutive weeks. Both groups were assigned 6.75 total hours of aerobic conditioning, and 13.5 hours of free weight and machine exercises totaling 3,188 repetitions ranging from 5 to 20 repetition maximums. The SEC group performed 2 cycling intervals per workout ranging from 10 to 45 seconds. Pretest and posttest measures included chest press and standing broad jump. Analysis of variance showed that there were no significant differences between the SE and SEC groups on measures of chest press or standing broad jump performance (p, not significant). Paired sample t-tests (p = 0.05) showed significant improvement in strength and power in all groups (pretest to posttest), except for SE jump performance (p, not significant). In conclusion, adding maximal-effort cycling does not provide additional strength or power benefits to a concurrent flexible nonlinear training program. However, an exercise professional can take confidence that a concurrent flexible nonlinear training program can increase strength and power in healthy individuals.

  19. Micro-/nanoscaled irreversible Otto engine cycle with friction loss and boundary effects and its performance characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Wenjie; Zhang, ChunQiang [School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Liao, Qinghong [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); He, Jizhou [Department of Physics, Nanchang University, Nanchang 330047 (China)

    2010-12-15

    An irreversible cycle model of the micro-/nanoscaled Otto engine cycle with internal friction loss is established. The general expressions of the work output and efficiency of the cycle are calculated based on the finite system thermodynamic theory, in which the quantum boundary effect of gas particles as working substance and the mechanical Casimir effect of gas system are considered. It is found that, for a micro-/nanoscaled Otto cycle devices, the work output W and efficiency {eta} of the cycle can be expressed as the functions of the temperature ratio {tau} of the two heat reservoirs, the volume ratio r{sub V} and the surface area ratio r{sub A} of the two isochoric processes, the dimensionless thermal wavelength {lambda} and other parameters of cycle, while for a macroscaled Otto cycle devices, the work output W{sub 0} and efficiency {eta}{sub 0} of the cycle are independent of the surface area ratio r{sub A} and the dimensionless thermal wavelength {lambda}. Further, the influence of boundary of cycle on the performance characteristics of the micro-/nanoscaled Otto cycle are analyzed in detail by introducing the output ratio W/W{sub 0} and efficiency ratio {eta}/{eta}{sub 0}. The results present the general performance characteristics of a micro-/nanoscaled Otto cycle and may serve as the basis for the design of a realistic Otto cycle device in micro-/nanoscale. (author)

  20. EFFECT OF SOMATOSTATIN ON THE CELL CYCLE OF HUMAN GALLBLADDER CANCER CELL

    Institute of Scientific and Technical Information of China (English)

    李济宇; 全志伟; 张强; 刘建文

    2005-01-01

    Objective To explore the effect of somatostatin on the cell cycle of human gallbladder cancer cell. Methods Growth curve of gallbladder cancer cell was measured after somatostatin treated on gradient concentration. Simultaneously, the change of gallbladder cancer cell cycle was detected using flow cytometry.Results Concentration-dependent cell growth inhibition caused by somatostatin was detected in gallbladder cancer cell(P<0.05). Cell growth was arrested in S phase since 12h after somatostatin treated, which reached its peak at 24h, then fell down. The changes in apoptosis index of gallbladder cancer cell caused by somatostatin correlated with that's in cell cycle. Conclusion Somatostatin could inhibit the cell growth of human gallbladder cancer cell in vitro on higher concentration. It might result from inducing growth arrest in S phase in early stage and inducing apoptosis in the late stage.

  1. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    DEFF Research Database (Denmark)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael;

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate...... pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote...... extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective...

  2. Quantum Otto cycle with inner friction: finite-time and disorder effects

    Science.gov (United States)

    Alecce, A.; Galve, F.; Lo Gullo, N.; Dell'Anna, L.; Plastina, F.; Zambrini, R.

    2015-07-01

    The concept of inner friction, by which a quantum heat engine is unable to follow adiabatically its strokes and thus dissipates useful energy, is illustrated in an exact physical model where the working substance consists of an ensemble of misaligned spins interacting with a magnetic field and performing the Otto cycle. The effect of this static disorder under a finite-time cycle gives a new perspective of the concept of inner friction under realistic settings. We investigate the efficiency and power of this engine and relate its performance to the amount of friction from misalignment and to the temperature difference between heat baths. Finally we propose an alternative experimental implementation of the cycle where the spin is encoded in the degree of polarization of photons.

  3. Effects of mimosine on Wolbachia in mosquito cells: cell cycle suppression reduces bacterial abundance.

    Science.gov (United States)

    Fallon, Ann M

    2015-10-01

    The plant allelochemical L-mimosine (β-[N-(3-hydroxy-4-pyridone)]-α-aminopropionic acid; leucenol) resembles the nonessential amino acid, tyrosine. Because the obligate intracellular alphaproteobacterium, Wolbachia pipientis, metabolizes amino acids derived from host cells, the effects of mimosine on infected and uninfected mosquito cells were investigated. The EC50 for mimosine was 6-7 μM with Aedes albopictus C7-10 and C/wStr cell lines, and was not influenced by infection status. Mosquito cells responded to concentrations of mimosine substantially lower than those used to synchronize the mammalian cell cycle; at concentrations of 30-35 μM, mimosine reversibly arrested the mosquito cell cycle at the G1/S boundary and inhibited growth of Wolbachia strain wStr. Although lower concentrations of mimosine slightly increased wStr abundance, concentrations that suppressed the cell cycle reduced Wolbachia levels.

  4. Interactive effects of ozone depletion and climate change on biogeochemical cycles.

    Science.gov (United States)

    Zepp, Richard G; Callaghan, Terry V; Erickson, David J

    2003-01-01

    The effects of ozone depiction on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the detailed interactions between ozone depletion and climate change are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B has significant effects on the terrestrial biosphere with important implications for the cycling of carbon, nitrogen and other elements. Increased UV has been shown to induce carbon monoxide production from dead plant matter in terrestrial ecosystems, nitrogen oxide production from Arctic and Antarctic snowpacks, and halogenated substances from several terrestrial ecosystems. New studies on UV effects on the decomposition of dead leaf material confirm that these effects are complex and species-specific. Decomposition can be retarded, accelerated or remain unchanged. It has been difficult to relate effects of UV on decomposition rates to leaf litter chemistry, as this is very variable. However, new evidence shows UV effects on some fungi, bacterial communities and soil fauna that could play roles in decomposition and nutrient cycling. An important new result is that not only is nitrogen cycling in soils perturbed significantly by increased UV-B, but that these effects persist for over a decade. As nitrogen cycling is temperature dependent, this finding clearly links the impacts of ozone depletion to the ability of plants to use nitrogen in a warming global environment. There are many other potential interactions between UV and climate change impacts on terrestrial biogeochemical cycles that remain to be quantified. There is also new evidence that UV-B strongly influences aquatic carbon, nitrogen, sulfur, and metals cycling that affect a wide range of life processes. UV-B accelerates the

  5. Enhancing the Effectiveness of Cycle Time Estimation in Wafer Fabrication-Efficient Methodology and Managerial Implications

    Directory of Open Access Journals (Sweden)

    Toly Chen

    2014-08-01

    Full Text Available Cycle time management plays an important role in improving the performance of a wafer fabrication factory. It starts from the estimation of the cycle time of each job in the wafer fabrication factory. Although this topic has been widely investigated, several issues still need to be addressed, such as how to classify jobs suitable for the same estimation mechanism into the same group. In contrast, in most existing methods, jobs are classified according to their attributes. However, the differences between the attributes of two jobs may not be reflected on their cycle times. The bi-objective nature of classification and regression tree (CART makes it especially suitable for tackling this problem. However, in CART, the cycle times of jobs of a branch are estimated with the same value, which is far from accurate. For these reason, this study proposes a joint use of principal component analysis (PCA, CART, and back propagation network (BPN, in which PCA is applied to construct a series of linear combinations of original variables to form new variables that are as unrelated to each other as possible. According to the new variables, jobs are classified using CART before estimating their cycle times with BPNs. A real case was used to evaluate the effectiveness of the proposed methodology. The experimental results supported the superiority of the proposed methodology over some existing methods. In addition, the managerial implications of the proposed methodology are also discussed with an example.

  6. Effects of Priming and Pacing Strategy on Oxygen-Uptake Kinetics and Cycling Performance.

    Science.gov (United States)

    Bailey, Stephen J; Vanhatalo, Anni; Black, Matthew I; DiMenna, Fred J; Jones, Andrew M

    2016-05-01

    To assess whether combining prior "priming" exercise with an all-out pacing strategy is more effective at improving oxygen-uptake (VO2) kinetics and cycling performance than either intervention administered independently. Nine men completed target-work cycling performance trials using a self-paced or all-out pacing strategy with or without prior severe-intensity (70%Δ) priming exercise. Breath-by-breath pulmonary VO2 and cycling power output were measured during all trials. Compared with the self-paced unprimed control trial (22 ± 5 s), the VO2 mean response time (MRT) was shorter (VO2 kinetics were faster) with all-out pacing (17 ± 4 s) and priming (17 ± 3 s), with the lowest VO2 MRT observed when all-out pacing and priming were combined (15 ± 4 s) (P primed trials (P primed (93 ± 8 s) and all-out primed (92 ± 8 s) trials (P .05). These findings suggest that combining an all-out start with severe-intensity priming exercise additively improves VO2 MRT but not total O2 consumption and cycling performance since these were improved by a similar magnitude in both primed trials relative to the self-paced unprimed control condition. Therefore, these results support the use of priming exercise as a precompetition intervention to improve oxidative metabolism and performance during short-duration high-intensity cycling exercise, independent of the pacing strategy adopted.

  7. The adverse effects of high fat induced obesity on female reproductive cycle and hormones

    Science.gov (United States)

    Donthireddy, Laxminarasimha Reddy

    The prevalence of obesity, an established risk and progression factor for abnormal reproductive cycle and tissue damage in female mice. It leads to earlier puberty, menarche in young females and infertility. There are extensive range of consequences of obesity which includes type-2 diabetes, cardiovascular disease and insulin resistance. Obesity is the interaction between dietary intake, genes, life style and environment. The interplay of hormones estrogen, insulin, and leptin is well known on energy homeostasis and reproduction. The aim of this study is to determine the effect of high fat induced obesity on reproductive cycles and its hormonal abnormalities on mice model. Two week, 3 month and 8 month long normal (WT) and very high fat diet (VHFD) diet course is followed. When mice are fed with very high fat diet, there is a drastic increase in weight within the first week later. There was a significant (pleptin levels in 6 month VHFD treated animals. 2 week, 3 month and 6 month time interval pap smear test results showed number of cells, length of estrous cycle and phases of the estrous cycle changes with VHFD mice(n=30) compared to normal diet mice(n=10). These results also indicate that the changes in the reproductive cycles in VHFD treated female mice could be due to the changes in hormones. Histo-pathological analyses of kidney, ovary, liver, pancreas, heart and lungs showed remarkable changes in some tissue on exposure to very high fat. Highly deposited fat packets observed surrounding the hepatocytes and nerve cells.

  8. Experimenter Effects on Pain Reporting in Women Vary across the Menstrual Cycle

    Directory of Open Access Journals (Sweden)

    Jacob M. Vigil

    2015-01-01

    Full Text Available Background. Separate lines of research have shown that menstrual cycling and contextual factors such as the gender of research personnel influence experimental pain reporting. Objectives. This study examines how brief, procedural interactions with female and male experimenters can affect experimentally reported pain (cold pressor task, CPT across the menstrual cycle. Methods. Based on the menstrual calendars 94 naturally cycling women and 38 women using hormonal contraceptives (Mage=19.83,  SD=3.09 were assigned to low and high fertility groups. This assignment was based on estimates of their probability of conception given their current cycle day. Experimenters (12 males, 7 females engaged in minimal procedural interactions with participants before the CPT was performed in solitude. Results. Naturally cycling women in the high fertility group showed significantly higher pain tolerance (81 sec, d=.79 following interactions with a male but not a female experimenter. Differences were not found for women in the low fertility or contraceptive groups. Discussion. The findings illustrate that menstrual functioning moderates the effect that experimenter gender has on pain reporting in women. Conclusion. These findings have implications for standardizing pain measurement protocols and understanding how basic biopsychosocial mechanisms (e.g., person-perception systems can modulate pain experiences.

  9. Impact of cycle-hysteresis interactions on the performance of giant magnetocaloric effect refrigerants

    Science.gov (United States)

    Brown, T. D.; Karaman, I.; Shamberger, P. J.

    2016-07-01

    Magnetic refrigeration technology based on the giant magnetocaloric effect in solid-state refrigerants is known qualitatively to be limited by dissipative mechanisms accompanying hysteresis in the magneto-structural solid-solid phase transition. In this paper, we quantitatively explore the dependence of cycle performance metrics (cooling power, temperature span, work input, and fractional Carnot efficiency) on hysteresis properties (thermal hysteresis, one-way transition width) of the magneto-structural phase transition in a Ni45Co5Mn36.6In13.4 alloy system. We investigate a variety of Ericsson-type magnetic refrigeration cycles, using a Preisach-based non-equilibrium thermodynamic framework to model the evolution of the alloy's magnetic and thermal properties. Performance metrics are found to depend strongly on hysteresis parameters, regardless of the cycle chosen. However, for a given hysteresis parameter set, the material's transformation temperatures determine a unique cycle that maximizes efficiency. For the model system used undergoing Ericsson cycles with 5 and 1.5 {{T}} maximum field constraint, fractional Carnot efficiencies in excess of 0.9 require thermal hysteresis below 1.5 {{K}} and 0.5 {{K}}, respectively. We conclude briefly with some general materials considerations for mitigating these hysteresis inefficiencies through microstructure design and other materials processing strategies.

  10. Effects of intraspecific competition on the life cycle of the stonefly, Nemurella pictetii (Plecoptera: Nemouridae

    Directory of Open Access Journals (Sweden)

    Zwick Peter

    2008-04-01

    Full Text Available Abstract Background Considerable variation of life cycle duration in given insect species has been frequently recorded. Splitting of populations into cohorts with different life cycle lengths may occur, sometimes even between siblings from the same batch. Larval populations of the stonefly Nemurella pictetii in central Europe regularly split into a very fast developing and a normal univoltine cohort, leading to partial multivoltinism. The causes for such variation remain unknown but presumably act on the larval stage in which most of the life cycle is spent. We therefore studied possible effects of intraspecific competition on growth and development of larvae in the laboratory. Results Intraspecific competition had important influence on growth and development of the larvae. High larval densities led to reduced growth and retarded development through interference, not through exploitative competition. All specimens were negatively affected by frequent encounters and the resulting disturbance. There were no dominant individuals able to grow and develop faster than the rest, at the expense of the others. Conclusion Differences in life cycle length of Nemurella pictetii may result from different larval densities in different microhabitats and resultant different degrees of interference competition. Although competition alone probably does not cause splitting of populations into cohorts with different life cycle duration differences in size and development caused by other factors are certainly enhanced by intraspecific competition.

  11. Residual thermal effects in macro fiber composite actuators exposed to persistent temperature cycling

    Science.gov (United States)

    Hobeck, J. D.; Owen, R. B.; Inman, D. J.

    2016-03-01

    In this letter, the authors present results of an experimental investigation demonstrating how extreme persistent thermal cycling influences the performance of piezoelectric macro fiber composite (MFC) actuators. More specifically, this research shows how repeated temperature cycling ranging from -60 °C to 90 °C and from -50 °C to 150 °C affects an MFCs ability to actuate while being driven at frequencies of 60 Hz to 90 Hz with a voltage of 20 Vpp. Experimental results show that thermal cycling causes MFC actuation characteristics to drift and eventually stabilize after approximately 20 cycles. In two cases presented here, thermal cycling alone caused a residual increase in actuation amplitude that exceeded the initial amplitude by 70%. This apparent thermal memory effect of MFCs may significantly impact the design and analysis of active structures where MFCs are used for vibration or displacement control in transient extreme temperature environments such as those encountered by aerospace structures, industrial equipment, automobiles, and civil infrastructure.

  12. Accelerating Effect of Wetting-Drying Cycles on Steel Bar Corrosion in Concrete

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Raining and sun-shining processes in natural climate were simulated by water spraying and infrared light shining alternately as wetting-drying cycles in accelerated durability test. The accelerating effects of the wetting-drying cycles and the variation of corrosion current density and corrosion potential of steel bar in concrete under such conditions were studied. The result shows that the main reason leading to accelerating corrosion of steel bar in concrete is the wetting-drying cycles, which can cause the increase of corrosion potential difference between the anode and cathode of steel bar corrosion cell and the decrease of concrete resistance. Corrosion rate of the steel bar in concrete under four typical conditions, including wetting-drying cycle, long time submerging in water, long time exposure to indoor and outdoor environment were measured and compared. The test results indicate that the corrosion rates under the four typical conditions are in the order of spraying and infrared light shining cycles, outdoor environment, indoor environment, and submerging in water, respectively.

  13. Experimental investigation of air relative humidity (RH) cycling tests on MEA/cell aging in PEMFC. Pt. I. Study of high RH cycling test with air RH at 62%/100%

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.T.; Chatillon, Y.; Bonnet, C.; Lapicque, F. [Laboratoire Reactions et Genie des Procedes, CNRS-Nancy University, Nancy (France); Leclerc, S. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, CNRS-Nancy University, Vandoeuvre-les-Nancy (France); Hinaje, M.; Rael, S. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, CNRS-Nancy University, Vandoeuvre-les-Nancy (France)

    2012-06-15

    The effect of high air relative humidity (RH) cycling (RH{sub C} 62%/100%) on the degradation mechanisms of a single (5 x 5 cm{sup 2}) proton exchange membrane fuel cells was investigated. The cell performance was compared to a cell operated at constant humidification (RH{sub C} = 62%). Runs were conducted over approximately 1,500 h at 0.3 A cm{sup -2}. The overall loss in cell performance for the high RH cycling test was 12 {mu}V h{sup -1} whereas it was at 3 {mu}V h{sup -1} under constant humidification. Impedance spectroscopy reveals that the ohmic and charge transfer resistances were little modified in both runs. H{sub 2} crossover measurement indicated that both high RH cycling and constant RH test did not promote serious effect on gas permeability. The electroactive surface loss for anode and cathode during high air RH cycling was more significant than at constant RH operation. The water uptake determined by {sup 1}H nuclear magnetic resonance within the membrane electrode assembly (MEA) after high RH cycling was reduced by 12% in comparison with a fresh MEA. Transmission electron microscopy showed bubbles and pinholes formation in the membrane, catalyst particles agglomeration (also observed by X-ray diffraction), catalyst particles migration in the membrane and thickness reduction of the catalytic layers. Scanning electron microscopy was conducted to observe the changes in morphology of gas diffusion layers after the runs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. The Effect of 7E Learning Cycle on Learning in Science Teaching: A Meta-Analysis Study

    Science.gov (United States)

    Balta, Nuri; Sarac, Hakan

    2016-01-01

    This article reports the results of a meta-analysis of the effectiveness of 7E learning cycle in science teaching. Totally 35 different effect sizes from 24 experimental studies, comprising 2918 students were included in the meta-analysis. The results confirmed that 7E learning cycle have a positive effect on students' achievement. The overall…

  15. Diversity and noise effects in a model of homeostatic regulation of the sleep-wake cycle.

    Directory of Open Access Journals (Sweden)

    Marco Patriarca

    Full Text Available Recent advances in sleep neurobiology have allowed development of physiologically based mathematical models of sleep regulation that account for the neuronal dynamics responsible for the regulation of sleep-wake cycles and allow detailed examination of the underlying mechanisms. Neuronal systems in general, and those involved in sleep regulation in particular, are noisy and heterogeneous by their nature. It has been shown in various systems that certain levels of noise and diversity can significantly improve signal encoding. However, these phenomena, especially the effects of diversity, are rarely considered in the models of sleep regulation. The present paper is focused on a neuron-based physiologically motivated model of sleep-wake cycles that proposes a novel mechanism of the homeostatic regulation of sleep based on the dynamics of a wake-promoting neuropeptide orexin. Here this model is generalized by the introduction of intrinsic diversity and noise in the orexin-producing neurons, in order to study the effect of their presence on the sleep-wake cycle. A simple quantitative measure of the quality of a sleep-wake cycle is introduced and used to systematically study the generalized model for different levels of noise and diversity. The model is shown to exhibit a clear diversity-induced resonance: that is, the best wake-sleep cycle turns out to correspond to an intermediate level of diversity at the synapses of the orexin-producing neurons. On the other hand, only a mild evidence of stochastic resonance is found, when the level of noise is varied. These results show that disorder, especially in the form of quenched diversity, can be a key-element for an efficient or optimal functioning of the homeostatic regulation of the sleep-wake cycle. Furthermore, this study provides an example of a constructive role of diversity in a neuronal system that can be extended beyond the system studied here.

  16. Experimental study on the long-term effect of cadmium in mice fed cadmium-polluted rice with special reference to the effect of repeated reproductive cycles

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, M.; Shiroishi, K.; Nishino, H.; Shinmura, T.; Murase, H.; Shoji, T.; Naruse, Y.; Kagamimori, S.

    1986-06-01

    Long-term biological effects of cadmium-polluted rice and effect of repeated reproductive cycles on them were examined. Female SLC-B6D2F mice (female C57BL/6, male DBA/2) were fed a rice diet containing 65% unpolished rice for about 2 years from 7 weeks of age. The unpolished rice preparations used were commercially available rice (non-Cd-polluted) and Cd-polluted rice (over 1.0 ppm). Average Cd contents in each diet class were 0.12, 0.48, 1.78, 1.75, and 47.1 ppm (50 ppm Cd as CdCl/sub 2/ added). Some experimental mice were subjected to repeated reproductive cycles (parity group). Hematological, biochemical, and pathological examinations of urine, blood, and tissues, including Cd measurement, were carried out. Results after statistical analysis indicate Cd toxicities such as anemia and disturbances of Ca metabolism. These Cd effects were found to be enhanced by the reproductive cycles. Soft X-ray radiograms showed osteoporosis in the parity groups, especially in the groups with diets of higher Cd content. However, we could not find any sign of disturbance of renal function under our experimental conditions.

  17. Age and time effects on implicit and explicit learning

    NARCIS (Netherlands)

    Verneau, M.; Kamp, J. van der; Savelsbergh, G.J.P.; Looze, M.P. de

    2014-01-01

    Study Context: It has been proposed that effects of aging are more pronounced for explicit than for implicit motor learning. The authors evaluated this claim by comparing the efficacy of explicit and implicit learning of a movement sequence in young and older adults, and by testing the resilience ag

  18. The Effect of Mixed-Age Classes in Sweden

    Science.gov (United States)

    Lindstrom, Elly-Ann; Lindahl, Erica

    2011-01-01

    Mixed-aged (MA) classes are a common phenomenon around the world. In Sweden, these types of classes increased rapidly during the 1980s and 1990s, despite the fact that existing empirical support for MA classes is weak. In this paper, the effect of attending an MA class during grades 4-6 on students' cognitive skills is estimated. Using a unique…

  19. Hypertext for the Aged: Effects of Text Topologies.

    Science.gov (United States)

    Lin, Dyi-Yih Michael

    2003-01-01

    Examined the effects of different text typologies on older users' (age 57-67) performance in hypertext perusal. Compared two text typologies, hierarchical and referential, that were constructed with HTML, and discusses hypertext navigation problems with older users related to human spatial orientation. (Author/LRW)

  20. Motivational effects and age differences of gamification in product advertising

    NARCIS (Netherlands)

    Bittner, Jenny V.; Schipper, Jeffrey

    2014-01-01

    Purpose – The purpose of this paper is to study motivational effects and age differences of gamification in product advertising. Game-elements can easily be embedded within product advertisements, but little is known about the success factors of this technology. We investigated which motivational in