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Sample records for stretch-shortening cycles age

  1. 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 jumps...

  2. Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

    DEFF Research Database (Denmark)

    Caserotti, Paolo; Aagaard, Per; Simonsen, Erik Bruun

    2001-01-01

    Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions......Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions...

  3. Achilles tendinopathy alters stretch shortening cycle behaviour during a sub-maximal hopping task.

    Science.gov (United States)

    Debenham, James R; Travers, Mervyn J; Gibson, William; Campbell, Amity; Allison, Garry T

    2016-01-01

    To describe stretch shortening cycle behaviour of the ankle and lower limb in patients with Achilles tendinopathy (AT) and establish differences with healthy volunteers. Between-subjects case-controlled. Fifteen patients with AT (mean age 41.2±12.7 years) and 11 healthy volunteers (CON) (mean age 23.2±6.7 years) performed sub-maximal single-limb hopping on a custom built sledge-jump system. Using 3D motion analysis and surface EMG, temporal kinematic (lower limb stiffness, ankle angle at 80ms pre-contact, ankle angle at contact, peak ankle angle, ankle stretch amplitude) and EMG measures (onset, offset and peak times relative to contact) were captured. Data between AT and CON were compared statistically using a linear mixed model. Patients with AT exhibited significantly increased lower limb stiffness when compared to healthy volunteers (pbehaviour during sub-maximal hopping when compared with healthy volunteers. Patients with AT hop with greater lower limb stiffness, in a greater degree of ankle dorsiflexion and have a greater stretch amplitude. Likewise, delayed muscle activity is evident. These findings have implications in terms of informing the understanding of the pathoaetiology and management of AT. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. The effect of strength training, recreational soccer and running exercise on stretch-shortening cycle muscle performance during countermovement jumping

    DEFF Research Database (Denmark)

    Jakobsen, Markus Due; Sundstrup, Emil; Randers, Morten Bredsgaard

    2012-01-01

    The purpose of the present study was to evaluate the effect of contrasting training modalities on mechanical muscle performance and neuromuscular activity during maximal SSC (stretch-shortening cycle) countermovement jumps (CMJ). Bilateral countermovement jumping, surface electromyography (EMG...

  5. Factors of force potentiation induced by stretch-shortening cycle in plantarflexors.

    Directory of Open Access Journals (Sweden)

    Atsuki Fukutani

    Full Text Available Muscle force is potentiated by countermovement; this phenomenon is called stretch-shortening cycle (SSC effect. In this study, we examined the factors strongly related to SSC effect in vivo, focusing on tendon elongation, preactivation, and residual force enhancement. Twelve healthy men participated in this study. Ankle joint angle was passively moved by a dynamometer, with a range of motion from 15° dorsiflexion (DF to 15° plantarflexion (PF. Muscle contraction was evoked by electrical stimulation, with stimulation timing adjusted to elicit three types of contraction: (1 concentric contraction without preliminary contraction (CON, (2 concentric contraction after preliminary eccentric contraction (ECC, and (3 concentric contraction after preliminary isometric contraction (ISO. Joint torque was recorded at DF5°, PF0°, and PF5°, respectively. SSC effect was calculated as the ratio of joint torque obtained in ECC or ISO with respect to that obtained in CON at the aforementioned three joint angles. SSC effect was prominent in the first half of movement in both ECC (DF5°, 329.3 ± 101.2%; PF0°, 159.2 ± 29.4%; PF5°, 125.5 ± 20.8% and ISO (DF5°, 276.4 ± 87.0%; PF0°, 134.5 ± 24.5%; PF5°, 106.8 ± 18.0% conditions. SSC effect was significantly larger in ECC than in ISO at all joint angles (P < 0.001. Even without preliminary eccentric contraction (i.e., ISO condition, SSC effect was clearly large, indicating that a significant part of SSC effect is derived from preactivation. However, the active lengthening-induced force potentiation mechanism (residual force enhancement also contributes to SSC effect.

  6. THE EFFECTS OF A STRETCH-SHORTENING CYCLE FATIGUE PROTOCOL ON KNEE KINEMATICS DURING RUNNING IN UNTRAINED CHILDREN

    Directory of Open Access Journals (Sweden)

    Tsatalas T

    2010-06-01

    Full Text Available The purpose of the current study was to examine the effects of an intensive stretch shortening-cycle (SSC protocol (100 plyometric jumps on knee kinematics during running on a treadmill in healthy children using 3D kinematics. Twelve healthy and untrained children volunteered. Their mean + age, height and weight was 10,1±0,5 years, 142± 6,1 cm and 37 ±4,6kg, respectively. Muscle damage of lower extremities was caused by 100 maximal intensity plyometric jumps performed as 10 sets of 10 continuous jumps with a 30 second restperiod between sets. Muscle damage indicators [delayed onset muscle soreness (DOMS, knee-joint flexion/extension angles during running on a treadmill (speed at 2.8 m/s] were assessed pre-, 0h, 24h, 48h and 72h post exercise. Kinematic data were captured at 100 Hz using a six-camera 3D motion analysis system (VICON 612. Repeated measures one-way ANOVA with five levels were utilised for the parameters. Allmuscle damage indicators revealed significant changes post- compared to pre-exercise data (p<0.05. Kinematic analysis revealed that the 100 plyometric jumps decreased knee-joint angles at different phases of stance (impact, support, push-off phase. These changes were more evident just after (0h the protocol and 48h after this, and remained till 72h post at a great extent (p<0.05. Lastly, children suffered from delayed muscle soreness on their thigh muscles which remained only 24 hours after this (p<0.05. Muscle damage causesalterations in treadmill running in knee kinematics of untrained children probable due to differentiation of their central nervous system running strategy

  7. Dynamic Contractility and Efficiency Impairments in Stretch-Shortening Cycle Are Stretch-Load-Dependent After Training-Induced Muscle Damage

    NARCIS (Netherlands)

    Vaczi, Mark; Racz, Levente; Hortobagyi, Tibor; Tihanyi, Jozsef

    Vaczi, M, Racz, L, Hortobagyi, T, and Tihanyi, J. Dynamic contractility and efficiency impairments in stretch-shortening cycle are stretch-load-dependent after training-induced muscle damage. J Strength Cond Res 27(8): 2171-2179, 2013To determine the acute task and stretch-load dependency of

  8. Delayed influence of stretch-shortening cycle fatigue on large ankle joint position coded with static positional signals.

    Science.gov (United States)

    Regueme, S C; Barthèlemy, J; Gauthier, G M; Blin, O; Nicol, C

    2008-06-01

    This study examines the static position sense from the ankle joint following a unilateral exhaustive stretch-shortening cycle (SSC)-type exercise involving mostly the triceps surae muscle group. Fatigue effects were quantified within the exercised and non-exercised leg through a maximal isometric voluntary plantarflexion test (MVC) performed immediately before (Pre) and after the SSC exercise, and repeated 2 (D2) and 8 (D8) days later. The static position sense test consisted in active reproductions with the non-exercised ankle of two target dorsiflexed positions (small and large) previously maintained with either the non-exercised (control procedure) or the exercised ankle (fatigue procedure). This test was carried out at Pre, D2, and D8. At D2, the MVC test revealed significant decreases in voluntary soleus muscle activity and peak plantarflexion force. The position sense test showed no error in reproduction accuracy in the control procedure. In contrast, the fatigue procedure revealed an overestimation of the large dorsiflexed position, only, with an associated increase of the agonist tibialis muscle activity. In agreement with the antagonist (stretched) muscle influence on the position sense, this overestimation is mostly attributed to potential SSC fatigue effects on ascending proprioceptive afferents issued from the exercised/inflamed antagonist muscles.

  9. The effect of strength training, recreational soccer and running exercise on stretch-shortening cycle muscle performance during countermovement jumping.

    Science.gov (United States)

    Jakobsen, Markus Due; Sundstrup, Emil; Randers, Morten Bredsgaard; Kjær, Michael; Andersen, Lars L; Krustrup, Peter; Aagaard, Per

    2012-08-01

    The purpose of the present study was to evaluate the effect of contrasting training modalities on mechanical muscle performance and neuromuscular activity during maximal SSC (stretch-shortening cycle) countermovement jumps (CMJ). Bilateral countermovement jumping, surface electromyography (EMG) and muscle fiber size (CSA) were studied in untrained individuals (n=49, 21-45 yrs) pre and post 12 weeks of progressive heavy-resistance strength training (ST, n=8), recreational soccer training (SOC, n=15), high-intensity interval running (INT, n=7), continuous running (RUN, n=9) or continuation of an inactive life-style (CON, n=10). ST displayed shortened CMJ take-off time (pupward velocity of center of mass (COM), rate of vertical force development (RFD: ΔF(Z)/Δt), peak power production, rate of power development (RPD), mean plantar flexor EMG and peak hamstring rate of EMG rise (RER). Peak quadriceps EMG rate of rise increased in SOC (p.70) were observed following ST between training-induced changes in CMJ SSC muscle performance, neuromuscular activity and muscle fiber CSA, respectively. ST induced a more rapid CMJ take-off phase and elevated muscle power production, indicating a more explosive-type SSC muscle performance. No effects were detected in CMJ performance after continuous running, high-intensity interval running and recreational soccer, despite an increased muscle fiber CSA and quadriceps muscle activity in SOC. Enhanced neuromuscular activity in the hip extensors (hamstrings) and plantar flexors, and increased myofiber fiber size were responsible for the enhanced CMJ SSC muscle performance with ST. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. The drop height determines neuromuscular adaptations and changes in jump performance in stretch-shortening cycle training.

    Science.gov (United States)

    Taube, W; Leukel, C; Lauber, B; Gollhofer, A

    2012-10-01

    There is an ongoing discussion about how to improve jump performance most efficiently with plyometric training. It has been proposed that drop height influences the outcome, although longitudinal studies are missing. Based on cross-sectional drop jump studies showing height-dependent Hoffmann (H)-reflex activities, we hypothesized that the drop height should influence the neuromuscular activity and thus, the training result. Thirty-three subjects participated as a control or in one of two stretch-shortening cycle (SSC) interventions. Subjects either trained for 4 weeks doing drop jumps from 30, 50, and 75 cm drop heights (SSC1) or completed the same amount of jumps exclusively from 30 cm (SSC2). During training and testing (from 30, 50, and 75 cm), subjects were instructed to minimize the duration of ground contact and to maximize their rebound height. Rebound heights were significantly augmented after SSC1, but a trend was only observed after SSC2. In contrast, the duration of ground contact increased after SSC1 but decreased after SSC2. The performance index (rebound height/duration of ground contact) improved similarly after SSC1 (+14%) and SSC2 (+14%). Changes in performance were accompanied by neuromuscular adaptations: for SSC1, activity of the soleus increased toward take-off (between 120 and 170 ms after touchdown), whereas SSC2-trained subjects showed enhanced activity shortly after ground contact (20-70 ms after touch down). The present study demonstrates a strong link among drop height, neuromuscular adaptation, and performance in SSC training. As the improvement in the performance index was no different after SSC1 or SSC2, the decision whether to apply SSC1 or SSC2 should depend on the specific requirements of the sports discipline. © 2011 John Wiley & Sons A/S.

  11. The stretch-shortening cycle (SSC) revisited: residual force enhancement contributes to increased performance during fast SSCs of human m. adductor pollicis.

    Science.gov (United States)

    Seiberl, Wolfgang; Power, Geoffrey A; Herzog, Walter; Hahn, Daniel

    2015-05-01

    The stretch-shortening cycle (SSC) occurs in most everyday movements, and is thought to provoke a performance enhancement of the musculoskeletal system. However, mechanisms of this performance enhancement remain a matter of debate. One proposed mechanism is associated with a stretch-induced increase in steady-state force, referred to as residual force enhancement (RFE). As yet, direct evidence relating RFE to increased force/work during SSCs is missing. Therefore, forces of electrically stimulated m. adductor pollicis (n = 14 subjects) were measured during and after pure stretch, pure shortening, and stretch-shortening contractions with varying shortening amplitudes. Active stretch (30°, ω = 161 ± 6°s(-1)) caused significant RFE (16%, P stretch preceded active shortening) no force depression was found. Indeed for our specific case in which the shortening amplitude was only 1/3 of the lengthening amplitude, there was a remnant RFE (10%, P stretch-induced RFE is not immediately abolished during shortening and contributes to the increased force and work during SSCs. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  12. Mechanical, hormonal, and hypertrophic adaptations to 10 weeks of eccentric and stretch-shortening cycle exercise training in old males

    NARCIS (Netherlands)

    Vaczi, Mark; Nagy, Szilvia A.; Koszegi, Tamas; Ambrus, Mira; Bogner, Peter; Perlaki, Gabor; Orsi, Gergely; Toth, Katalin; Hortobagyi, Tibor

    2014-01-01

    The growth promoting effects of eccentric (ECC) contractions are well documented but it is unknown if the rate of stretch per se plays a role in such muscular responses in healthy aging human skeletal muscle. We tested the hypothesis that exercise training of the quadriceps muscle with low rate ECC

  13. Shortening-induced force depression is modulated in a time- and speed-dependent manner following a stretch-shortening cycle.

    Science.gov (United States)

    Fortuna, Rafael; Groeber, Martin; Seiberl, Wolfgang; Power, Geoffrey A; Herzog, Walter

    2017-06-01

    The steady-state isometric force following active muscle shortening or lengthening is smaller (force depression, FD) or greater (residual force enhancement, RFE) than a purely isometric contraction at the corresponding length. The mechanism underlying these phenomena is not explained within the context of the cross-bridge theory, with few studies investigating the effects of FD and RFE in stretching-shortening cycle (SSC). The purpose of this study was to perform SSC, where the time between the end of stretch and the end of shortening was manipulated by (1) adding a pause between stretch and shortening (protocol 1) or (2) performing the shortening contraction at different speeds (protocol 2). The results show that, in protocol 1, FD was reduced for SSC with a 0-sec and 0.5-sec interval between stretching and shortening, but was the same for SSC with a 1-sec interval compared to the pure FD condition. In protocol 2, FD was reduced for SSC with shortening speeds of 30 and 60°/sec, but was the same for shortening speeds of 15 and 20°/sec compared to the pure FD condition. These findings provide evidence that stretch preceding shortening affects FD in a time- and speed-dependent manner, providing new information on the potential mechanism of FD and RFE. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  14. Effects of Stretch Shortening Cycle Exercise Fatigue on Stress Fracture Injury Risk during Landing

    Science.gov (United States)

    James, C. Roger; Dufek, Janet S.; Bates, Barry T.

    2006-01-01

    The purpose of this study was to examine changes in landing performance during fatigue that could result in increased stress fracture injury risk. Five participants performed nonfatigued and fatigued drop landings (0.60 m), while ground reaction force (GRF), electromyographic (EMG) activity, and kinematics were recorded. Fatigue was defined as a…

  15. High-intensity stretch-shortening contraction training modifies responsivity of skeletal muscle in old male rats.

    Science.gov (United States)

    Rader, Erik P; Naimo, Marshall A; Ensey, James; Baker, Brent A

    2018-02-10

    Utilization of high-intensity resistance training to counter age-related sarcopenia is currently debated because of the potential for maladaptation when training design is inappropriate. Training design is problematic because the influence of various loading variables (e.g. contraction mode, repetition number, and training frequency) is still not well characterized at old age. To address this in a precisely controlled manner, we developed a rodent model of high-intensity training consisting of maximally-activated stretch-shortening contractions (SSCs), contractions typical during resistance training. With this model, we determined that at old age, high-repetition SSC training (80 SSCs: 8 sets of 10 repetitions) performed frequently (i.e. 3 days per week) for 4.5 weeks induced strength deficits with no muscle mass gain while decreasing frequency to 2 days per week promoted increases in muscle mass and muscle quality (i.e. performance normalized to muscle mass). This finding confirmed the popular notion that decreasing training frequency has a robust effect with age. Meanwhile, the influence of other loading variables remains contentious. The aim of the present study was to assess muscle adaptation following modulation of contraction mode and repetition number during high-intensity SSC training. Muscles of young (3 month old) and old (30 month old) male rats were exposed to 4.5 weeks of low-repetition static training of 4 (i.e. 4 sets of one repetition) isometric (ISO) contractions 3 days per week or a more moderate-repetition dynamic training of 40 SSCs (i.e. 4 sets of 10 repetitions) 3 days per week. For young rats, performance and muscle mass increased regardless of training protocol. For old rats, no muscle mass adaptation was observed for 4 ISO training while 40 SSC training induced muscle mass gain without improvement in muscle quality, an outcome distinct from modulating training frequency. Muscle mass gain for old rats was accompanied by

  16. Agonist muscle adaptation accompanied by antagonist muscle atrophy in the hindlimb of mice following stretch-shortening contraction training.

    Science.gov (United States)

    Rader, Erik P; Naimo, Marshall A; Ensey, James; Baker, Brent A

    2017-02-02

    The vast majority of dynamometer-based animal models for investigation of the response to chronic muscle contraction exposure has been limited to analysis of isometric, lengthening, or shortening contractions in isolation. An exception to this has been the utilization of a rat model to study stretch-shortening contractions (SSCs), a sequence of consecutive isometric, lengthening, and shortening contractions common during daily activity and resistance-type exercise. However, the availability of diverse genetic strains of rats is limited. Therefore, the purpose of the present study was to develop a dynamometer-based SSC training protocol to induce increased muscle mass and performance in plantarflexor muscles of mice. Young (3 months old) C57BL/6 mice were subjected to 1 month of plantarflexion SSC training. Hindlimb muscles were analyzed for muscle mass, quantitative morphology, myogenesis/myopathy relevant gene expression, and fiber type distribution. The main aim of the research was achieved when training induced a 2-fold increase in plantarflexion peak torque output and a 19% increase in muscle mass for the agonist plantaris (PLT) muscle. In establishing this model, several outcomes emerged which raised the value of the model past that of being a mere recapitulation of the rat model. An increase in the number of muscle fibers per transverse muscle section accounted for the PLT muscle mass gain while the antagonist tibialis anterior (TA) muscle atrophied by 30% with preferential atrophy of type IIb and IIx fibers. These alterations were accompanied by distinct gene expression profiles. The findings confirm the development of a stretch-shortening contraction training model for the PLT muscle of mice and demonstrate that increased cross-sectional fiber number can occur following high-intensity SSC training. Furthermore, the TA muscle atrophy provides direct evidence for the concept of muscle imbalance in phasic non-weight bearing muscles, a concept largely

  17. Concentrically trained cyclists are not more susceptible to eccentric exercise-induced muscle damage than are stretch-shortening exercise-trained runners.

    Science.gov (United States)

    Snieckus, Audrius; Kamandulis, Sigitas; Venckūnas, Tomas; Brazaitis, Marius; Volungevičius, Gintautas; Skurvydas, Albertas

    2013-03-01

    Here, we test the hypothesis that continuous concentric exercise training renders skeletal muscles more susceptible to damage in response to eccentric exercise. Elite road cyclists (CYC; n = 10, training experience 8.1 ± 2.0 years, age 22.9 ± 3.7 years), long-distance runners (LDR; n = 10, 9.9 ± 2.3 years, 24.4 ± 2.5 years), and healthy untrained (UT) men (n = 10; 22.4 ± 1.7 years) performed 100 submaximal eccentric contractions at constant angular velocity of 60° s(-1). Concentric isokinetic peak torque, isometric maximal voluntary contraction (MVC), and electrically induced knee extension torque were measured at baseline and immediately and 48 h after an eccentric exercise bout. Muscle soreness was assessed and plasma creatine kinase (CK) activity was measured at baseline and 48 h after exercise. Voluntary and electrically stimulated knee extension torque reduction were significantly greater (p < 0.05) in UT than in LDR and CYC. Immediately and 48 h after exercise, MVC decreased by 32 % and 20 % in UT, 20 % and 5 % in LDR, and 25 % and 6 % in CYC. Electrically induced 20 Hz torque decreased at the same times by 61 and 29 % in UT, 40 and 17 % in LDR, and 26 and 14 % in CYC. Muscle soreness and plasma CK activity 48 h after exercise did not differ significantly between athletes and UT subjects. In conclusion, even though elite endurance athletes are more resistant to eccentric exercise-induced muscle damage than are UT people, stretch-shortening exercise-trained LDR have no advantage over concentrically trained CYC.

  18. The drop height determines neuromuscular adaptations and changes in jump performance in stretch-shortening cycle training

    OpenAIRE

    Taube, Wolfgang; Leukel, Christian; Lauber, B.; Gollhofer, Albert

    2012-01-01

    There is an ongoing discussion about how to improve jump performance most efficiently with plyometric training. It has been proposed that drop height influences the outcome, although longitudinal studies are missing. Based on cross-sectional drop jump studies showing height-dependent Hoffmann (H)-reflex activities, we hypothesized that the drop height should influence the neuromuscular activity and thus, the training result. Thirty-three subjects participated as a control or in one of two str...

  19. Life Cycle Management Strategies for Aging Engines

    Science.gov (United States)

    2003-02-01

    Reunions des specialistes des techniques de estion du cycle de vie pour vehicules aeriens vieillissants ] To order the complete compilation report, use...Mechanisms and Control. Specialists’ Meeting on Life Management Techniques for Ageing Air Vehicles [Les mecanismes vieillissants et le controle...protective coatings or surface modification treatments [3,7-9], while FOD can be repaired within limits, as detailed below [10]. 2.1.2. Internal

  20. Old age mortality and macroeconomic cycles.

    Science.gov (United States)

    Rolden, Herbert J A; van Bodegom, David; van den Hout, Wilbert B; Westendorp, Rudi G J

    2014-01-01

    As mortality is more and more concentrated at old age, it becomes critical to identify the determinants of old age mortality. It has counter-intuitively been found that mortality rates at all ages are higher during short-term increases in economic growth. Work-stress is found to be a contributing factor to this association, but cannot explain the association for the older, retired population. Historical figures of gross domestic product (Angus Maddison) were compared with mortality rates (Human Mortality Database) of middle aged (40-44 years) and older people (70-74 years) in 19 developed countries for the period 1950-2008. Regressions were performed on the de-trended data, accounting for autocorrelation and aggregated using random effects models. Most countries show pro-cyclical associations between the economy and mortality, especially with regard to male mortality rates. On average, for every 1% increase in gross domestic product, mortality increases with 0.36% for 70-year-old to 74-year-old men (p<0.001) and 0.38% for 40-year-old to 44-year-old men (p<0.001). The effect for women is 0.18% for 70-year-olds to 74-year-olds (p=0.012) and 0.15% for 40-year-olds to 44-year-olds (p=0.118). In developed countries, mortality rates increase during upward cycles in the economy, and decrease during downward cycles. This effect is similar for the older and middle-aged population. Traditional explanations as work-stress and traffic accidents cannot explain our findings. Lower levels of social support and informal care by the working population during good economic times can play an important role, but this remains to be formally investigated.

  1. Polity age and political budget cycles

    DEFF Research Database (Denmark)

    Aaskoven, Lasse

    2017-01-01

    Incumbent incentive for competence-signaling and lack of voter information are generally thought to be factors that increase the prevalence of political budget cycles. These mechanisms should be more prevalent in new political units. Since the creation of new political units is rarely exogenous......-experimental to study whether political budget cycles are larger in new political units. Contrary to theoretical predictions, political budget cycles seem to be of a smaller scale in the new municipalities, but only regarding budget cycles in budgetary overruns. The findings are of wider interest for discussions about...... the mechanisms behind context-conditional political budget cycles....

  2. Age-related decrements in cycling and running performance ...

    African Journals Online (AJOL)

    Results. The rate of decline in running speed occurred at an earlier age (~ 32 years) during the running race compared with the cycling tour (~ 55 years). Conclusions. These findings establish a trend that there is 'accelerated' aging during running which can perhaps be attributed to the increased weight-bearing stress on ...

  3. Life cycle cost analysis of aging aircraft airframe maintenance

    Science.gov (United States)

    Sperry, Kenneth Robert

    Scope and method of study. The purpose of this study was to examine the relationship between an aircraft's age and its annual airframe maintenance costs. Common life cycle costing methodology has previously not recognized the existence of this cost growth potential, and has therefor not determined the magnitude nor significance of this cost element. This study analyzed twenty-five years of DOT Form 41-airframe maintenance cost data for the Boeing 727, 737, 747 and McDonnell Douglas DC9 and DC-10 aircraft. Statistical analysis included regression analysis, Pearson's r, and t-tests to test the null hypothesis. Findings and conclusion. Airframe maintenance cost growth was confirmed to be increasing after an aircraft's age exceeded its designed service objective of approximately twenty-years. Annual airframe maintenance cost growth increases were measured ranging from 3.5% annually for a DC-9, to approximately 9% annually for a DC-10 aircraft. Average measured coefficient of determination between age and airframe maintenance, exceeded .80, confirming a strong relationship between cost: and age. The statistical significance of the difference between airframe costs sampled in 1985, compared to airframe costs sampled in 1998 was confirmed by t-tests performed on each subject aircraft group. Future cost forecasts involving aging aircraft subjects must address cost growth due to aging when attempting to model an aircraft's economic service life.

  4. Stressing the cell cycle in senescence and aging.

    Science.gov (United States)

    Chandler, Hollie; Peters, Gordon

    2013-12-01

    Senescence represents a permanent exit from the cell cycle and its role in curtailing the proliferation of damaged and potentially oncogenic cells has relevance both as a front-line defense against cancer and as an underlying cause of aging. The retinoblastoma protein (RB) and p53 tumor suppressors are central to the process and the growth arrest is primarily implemented by the cyclin-dependent kinase (CDK) inhibitors, p16INK4a and p21CIP1. In contrast to terminal differentiation, senescence is a general response to a diverse range of cellular stresses and is typically accompanied by a characteristic set of phenotypic changes. Of particular note is a secretory program whose autocrine and paracrine effects can advertize the presence of senescent cells within a tissue and promote their clearance by the immune system. In this short review, we will highlight recent advances in understanding the relationship between senescence and aging and the distinction between senescence and terminal differentiation, from a cell cycle perspective. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. The effect of different training programs on eccentric energy utilization in college-aged males.

    Science.gov (United States)

    Hawkins, Sheldon B; Doyle, Tim L A; McGuigan, Michael R

    2009-10-01

    The Eccentric Utilization Ratio (EUR), which is the ratio of countermovement jump (CMJ) to squat jump (SJ) performance measures, is a useful indicator of training status in elite athletes and their utilization of the stretch-shortening cycle. This investigation sought to determine if EUR was sensitive to different types of resistance training in untrained college-aged males. Twenty-nine college-aged males completed 8 weeks of training and were randomly allocated to 1 of 3 training programs: weight training (n = 10), plyometrics (n = 10), or weightlifting (n = 9). Testing occurred 3 times (pre, mid, post) with a CMJ and SJ conducted on a force plate integrated with a position transducer. Height, weight, and a 1RM (repetition maximum) squat also were measured. Weightlifting significantly (p power than plyometrics for height and power for both CMJ and SJ results. This investigation indicated EUR did not significantly change, suggesting that this type of performance indicator may not be useful in a recreationally active population. Alternatively, an 8-week training program might not be a long enough time period to see changes in this group of participants. Results did indicate that high-velocity and high-force training programs, consisting of weightlifting and plyometrics, improved lower-body performance, especially in the areas of jump height and power.

  6. 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.

  7. Built Environment Features that Promote Cycling in School-Aged Children.

    Science.gov (United States)

    Larouche, Richard

    2015-12-01

    Previous research shows that children and youth who cycle to/from school are more active and fitter than those who travel by motorized modes. However, rates of cycling are low in many countries, and a better understanding of the correlates of cycling may inform the development of future interventions. This review summarizes the current literature on the built environment correlates of cycling among school-aged children and youth. While both studies of transportation and recreational cycling were eligible, the majority of the 12 included studies focused on the trip to/from school and consistently indicated that shorter distance between home and school is associated with greater odds of cycling. However, little is known about the correlates of cycling for other purposes. Furthermore, other built environment features have not been studied enough to allow strong conclusions to be drawn. Recommendations for future studies are proposed to address the limitations of current evidence.

  8. 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 type I muscle fibers was higher in the trained groups (P type and cycling efficiency at any work rate or cadence combination. Stepwise multiple regression indicated that muscle fiber type did not influence cycling performance (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.

  9. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    NARCIS (Netherlands)

    Goldenbeld, C. Houtenbos, M. Ehlers, E. & Waard, D. de

    2012-01-01

    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. The main research questions concerned age differences in the self-reported use of

  11. 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

  12. Microstructural characterization and thermal cycling reliability of solders under isothermal aging and electrical current

    Science.gov (United States)

    Chauhan, Preeti Singh

    Solder joints on printed circuit boards provide electrical and mechanical connections between electronic devices and metallized patterns on boards. These solder joints are often the cause of failure in electronic packages. Solders age under storage and operational life conditions, which can include temperature, mechanical loads, and electrical current. Aging occurring at a constant temperature is called isothermal aging. Isothermal aging leads to coarsening of the bulk microstructure and increased interfacial intermetallic compounds at the solder-pad interface. The coarsening of the solder bulk degrades the creep properties of solders, whereas the voiding and brittleness of interfacial intermetallic compounds leads to mechanical weakness of the solder joint. Industry guidelines on solder interconnect reliability test methods recommend preconditioning the solder assemblies by isothermal aging before conducting reliability tests. The guidelines assume that isothermal aging simulates a "reasonable use period," but do not relate the isothermal aging levels with specific use conditions. Studies on the effect of isothermal aging on the thermal cycling reliability of tin-lead and tin-silver-copper solders are limited in scope, and results have been contradictory. The effect of electrical current on solder joints has been has mostly focused on current densities above 104A/cm2 with high ambient temperature (≥100oC), where electromigration, thermomigration, and Joule heating are the dominant failure mechanisms. The effect of current density below 104A/cm2 on temperature cycling fatigue of solders has not been established. This research provides the relation between isothermal aging and the thermal cycling reliability of select Sn-based solders. The Sn-based solders with 3%, 1%, and 0% silver content that have replaced tin-lead are studied and compared against tin-lead solder. The activation energy and growth exponents of the Arrhenius model for the intermetallic growth in

  13. Patterns and prevalence of medication use across the menstrual cycle among healthy, reproductive aged women

    Science.gov (United States)

    Johnson, KA; Sjaarda, LA; Mumford, SL; Garbose, RA; Schliep, KC; Mattison, D; Perkins, NJ; Wactawski-Wende, J; Schisterman, EF

    2016-01-01

    Purpose To characterize the patterns of medication intake in healthy, reproductive-age women not using hormonal contraception. Methods 259 healthy, premenopausal women (18–44 years of age) enrolled in the BioCycle Study (2005–2007), were followed over two menstrual cycles. Women were excluded if they were currently using oral contraceptives or other chronic medications. Over-the-counter and prescription medication use among participants was evaluated daily throughout the study via a diary assessing type of medication, dosage, units, and frequency. Medications were categorized as allergy, antibiotics, central nervous system (CNS), cold and cough, gastrointestinal (GI), musculoskeletal, and pain medication based on primary active ingredient. Medication use within each category was assessed across standardized 28-day cycles to evaluate differences in use across cycle phases (i.e. early, mid, late). Results Medication use was reported by 73% of participants. The most and least frequently used medications, respectively, were pain (69%) and musculoskeletal medications (1%). Pain, CNS, and antibiotic medication use varied significantly across the cycle, with pain and CNS medication more frequently reported during menses and antibiotics more frequently during the luteal phase. Allergy, cold and cough, GI, and musculoskeletal medication use did not vary across the cycle. Conclusions Patterns of medication use among reproductive-age women vary across the menstrual cycle for certain types of medications, particularly in pain (e.g. Ibuprofen), antibiotics (e,g, Amoxicillin), and CNS (e.g. Adderall) medications. Future studies involving use of these types of medication in premenopausal women may need to consider the relationship of their use to the menstrual cycle. PMID:26954695

  14. Patterns and prevalence of medication use across the menstrual cycle among healthy, reproductive aged women.

    Science.gov (United States)

    Johnson, Kristen A; Sjaarda, Lindsey A; Mumford, Sunni L; Garbose, Rebecca A; Schliep, Karen C; Mattison, Donald; Perkins, Neil J; Wactawski-Wende, Jean; Schisterman, Enrique F

    2016-06-01

    The purpose of this study is to characterize the patterns of medication intake in healthy, reproductive-age women not using hormonal contraception. Two hundered fifty-nine healthy, premenopausal women (18-44 years of age) enrolled in the BioCycle Study (2005-2007) were followed over two menstrual cycles. Women were excluded if they were currently using oral contraceptives or other chronic medications. Over-the-counter and prescription medication use among participants was evaluated daily throughout the study via a diary assessing type of medication, dosage, units, and frequency. Medications were categorized as allergy, antibiotics, central nervous system (CNS), cold and cough, gastrointestinal, musculoskeletal, and pain medication based on primary active ingredient. Medication use within each category was assessed across standardized 28-day cycles to evaluate differences in use across cycle phases (i.e., early, middle, and late). Medication use was reported by 73% of participants. The most and least frequently used medications, respectively, were pain (69%) and musculoskeletal medications (1%). Pain, CNS, and antibiotic medication use varied significantly across the cycle, with pain and CNS medication more frequently reported during menses and antibiotics more frequently during the luteal phase. Allergy, cold and cough, gastrointestinal, and musculoskeletal medication use did not vary across the cycle. Patterns of medication use among reproductive age women vary across the menstrual cycle for certain types of medications, particularly in pain (e.g., Ibuprofen), antibiotics (e,g, Amoxicillin), and CNS (e.g., Adderall) medications. Future studies involving use of these types of medication in premenopausal women may need to consider the relationship of their use to the menstrual cycle. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Physical environmental factors related to walking and cycling in older adults: the Belgian aging studies

    Directory of Open Access Journals (Sweden)

    Van Cauwenberg Jelle

    2012-02-01

    Full Text Available Abstract Background Socio-ecological models emphasize the relationship between the physical environment and physical activity (PA. However, knowledge about this relationship in older adults is limited. Therefore, the present study aims to investigate the relationship between area of residence (urban, semi-urban or rural and older adults' walking and cycling for transportation and recreation. Additionally, relationships between several physical environmental factors and walking and cycling and possible moderating effects of area of residence, age and gender were studied. Methods Data from 48,879 Flemish older adults collected in 2004-2010 through peer research were analyzed. Walking, cycling and environmental perceptions were assessed using self-administered questionnaires. The Study Service of the Flemish Government provided objective data on municipal characteristics. Multilevel logistic regression analyses were applied. Results Urban participants were more likely to walk daily for transportation compared to rural (OR = 1.43; 95% CI = 1.22, 1.67 and semi-urban participants (OR = 1.32; 95% CI = 1.13, 1.54. Urban participants were less likely to cycle daily for transportation compared to semi-urban participants (OR = 0.72; 95% CI = 0.56, 0.92. Area of residence was unrelated to weekly recreational walking/cycling. Perceived short distances to services (ORs ranging from 1.04 to 1.19 and satisfaction with public transport (ORs ranging from 1.07 to 1.13 were significantly positively related to all walking/cycling behaviors. Feelings of unsafety was negatively related to walking for transportation (OR = 0.93, 95% CI = 0.91, 0.95 and recreational walking/cycling (OR = 0.95, 95% CI = 0.92, 0.97. In females, it was also negatively related to cycling for transportation (OR = 0.94, 95% CI = 0.90, 0.98. Conclusions Urban residents were more likely to walk for transportation daily compared to semi-urban and rural residents. Daily cycling for transportation

  16. Physical environmental factors related to walking and cycling in older adults: the Belgian aging studies

    Science.gov (United States)

    2012-01-01

    Background Socio-ecological models emphasize the relationship between the physical environment and physical activity (PA). However, knowledge about this relationship in older adults is limited. Therefore, the present study aims to investigate the relationship between area of residence (urban, semi-urban or rural) and older adults' walking and cycling for transportation and recreation. Additionally, relationships between several physical environmental factors and walking and cycling and possible moderating effects of area of residence, age and gender were studied. Methods Data from 48,879 Flemish older adults collected in 2004-2010 through peer research were analyzed. Walking, cycling and environmental perceptions were assessed using self-administered questionnaires. The Study Service of the Flemish Government provided objective data on municipal characteristics. Multilevel logistic regression analyses were applied. Results Urban participants were more likely to walk daily for transportation compared to rural (OR = 1.43; 95% CI = 1.22, 1.67) and semi-urban participants (OR = 1.32; 95% CI = 1.13, 1.54). Urban participants were less likely to cycle daily for transportation compared to semi-urban participants (OR = 0.72; 95% CI = 0.56, 0.92). Area of residence was unrelated to weekly recreational walking/cycling. Perceived short distances to services (ORs ranging from 1.04 to 1.19) and satisfaction with public transport (ORs ranging from 1.07 to 1.13) were significantly positively related to all walking/cycling behaviors. Feelings of unsafety was negatively related to walking for transportation (OR = 0.93, 95% CI = 0.91, 0.95) and recreational walking/cycling (OR = 0.95, 95% CI = 0.92, 0.97). In females, it was also negatively related to cycling for transportation (OR = 0.94, 95% CI = 0.90, 0.98). Conclusions Urban residents were more likely to walk for transportation daily compared to semi-urban and rural residents. Daily cycling for transportation was less prevalent

  17. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Nitrogen cycling and bacterial community structure of sinking and aging diatom aggregates

    DEFF Research Database (Denmark)

    Lundgaard, Ann Sofie Birch; Treusch, Alexander H.; Stief, Peter

    2017-01-01

    are unknown. Thus, model aggregates prepared from the diatom Skeletonema marinoi were allowed to age for 4 d at high and low ambient O2 levels (70 and 15% air saturation, respectively), and changes in nitrogen transformations and microbial community structure were followed. At both O2 levels, denitrification...... and dissimilatory NO3– reduction to NO2– (DNRN) were the most important processes of aggregate-associated anaerobic nitrogen cycling. However, at 70% air saturation, rates of anaerobic N cycling were lower and decayed towards 0 after an early rise, whereas at 15% air saturation, they remained constantly high...

  19. Evaluation of corneal thickness alterations during menstrual cycle in productive age women

    Directory of Open Access Journals (Sweden)

    Negar Amiri Ghahfarokhi

    2015-01-01

    Full Text Available Purpose: To determine the change in corneal thickness through different phases of menstrual cycle in women who are in their productive age. Materials and Methods: Fifty healthy women with normal past medical history were enrolled in this prospective study. Central corneal thickness was measured with ultrasound pachymeter three times during a menstrual cycle: Beginning of the cycle (days 1-3, ovulation time, and at the end of cycle (days 27-32. We confirmed ovulation time with determining a peak in luteinizing hormone in urine. To avoid the diurnal variation of the corneal thickness which is well recognized, we checked all our subjects at 10 in the morning. Results: In days 1 to 3 of menstruation, mean corneal thickness was 541.40±11.36 and 540.82±11.70 microns for left and right eyes respectively. At ovulation time the mean thickness changed to 556.50±7.11 and 555.98±7.26 microns for left and right eyes respectively, and at the end of the cycle, the corneal thickness turned in to 536.38±12.83 and 535.48±13.08 microns for left and right eyes respectively. The difference of corneal thickness was statistically significant relating to the different stages of menstrual cycle. Conclusion: The thickest cornea during the menstruation cycle is achieved at the ovulation time and the thinnest at the end of the cycle and this should be taken in to account whilst plan to do a corneal refractive surgery.

  20. 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.

  1. Influence of Age, Reproductive Cycling Status, and Menstruation on the Vaginal Microbiome in Baboons (Papio anubis)

    Science.gov (United States)

    UCHIHASHI, M.; BERGIN, I. L.; BASSIS, C. M.; HASHWAY, S. A.; CHAI, D.; BELL, J. D.

    2015-01-01

    The vaginal microbiome is believed to influence host health by providing protection from pathogens and influencing reproductive outcomes such as fertility and gestational length. In humans, age-associated declines in diversity of the vaginal microbiome occur in puberty and persist into adulthood. Additionally, menstruation has been associated with decreased microbial community stability. Adult female baboons, like other non-human primates (NHPs), have a different and highly diverse vaginal microbiome compared to that of humans, which is most commonly dominated by Lactobacillus spp. We evaluated the influence of age, reproductive cycling status (cycling vs. non-cycling) and menstruation on the vaginal microbiome of 38 wild-caught, captive female olive baboons (Papio anubis) by culture-independent sequencing of the V3–V5 region of the bacterial 16S rRNA gene. All baboons had highly diverse vaginal microbial communities. Adult baboons had significantly lower microbial diversity in comparison to subadult baboons, which was attributable to decreased relative abundance of minor taxa. No significant differences were detected based on cycling state or menstruation. Predictive metagenomic analysis showed uniformity in relative abundance of metabolic pathways regardless of age, cycle stage, or menstruation, indicating conservation of microbial community functions. This study suggests that selection of an optimal vaginal microbial community occurs at puberty. Since decreased diversity occurs in both baboons and humans at puberty, this may reflect a general strategy for selection of adult vaginal microbial communities. Comparative evaluation of vaginal microbial community development and composition may elucidate mechanisms of community formation and function that are conserved across host species or across microbial community types. These findings have implications for host health, evolutionary biology, and microbe-host ecosystems. PMID:25676781

  2. Influence of age, reproductive cycling status, and menstruation on the vaginal microbiome in baboons (Papio anubis).

    Science.gov (United States)

    Uchihashi, M; Bergin, I L; Bassis, C M; Hashway, S A; Chai, D; Bell, J D

    2015-05-01

    The vaginal microbiome is believed to influence host health by providing protection from pathogens and influencing reproductive outcomes such as fertility and gestational length. In humans, age-associated declines in diversity of the vaginal microbiome occur in puberty and persist into adulthood. Additionally, menstruation has been associated with decreased microbial community stability. Adult female baboons, like other non-human primates (NHPs), have a different and highly diverse vaginal microbiome compared to that of humans, which is most commonly dominated by Lactobacillus spp. We evaluated the influence of age, reproductive cycling status (cycling vs. non-cycling) and menstruation on the vaginal microbiome of 38 wild-caught, captive female olive baboons (Papio anubis) by culture-independent sequencing of the V3-V5 region of the bacterial 16S rRNA gene. All baboons had highly diverse vaginal microbial communities. Adult baboons had significantly lower microbial diversity in comparison to subadult baboons, which was attributable to decreased relative abundance of minor taxa. No significant differences were detected based on cycling state or menstruation. Predictive metagenomic analysis showed uniformity in relative abundance of metabolic pathways regardless of age, cycle stage, or menstruation, indicating conservation of microbial community functions. This study suggests that selection of an optimal vaginal microbial community occurs at puberty. Since decreased diversity occurs in both baboons and humans at puberty, this may reflect a general strategy for selection of adult vaginal microbial communities. Comparative evaluation of vaginal microbial community development and composition may elucidate mechanisms of community formation and function that are conserved across host species or across microbial community types. These findings have implications for host health, evolutionary biology, and microbe-host ecosystems. © 2015 Wiley Periodicals, Inc.

  3. 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.

  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 role

  5. 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

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

    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...... 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...... the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing. © 2016 The Author(s)....

  7. 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

    the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing.......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...... 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...

  8. 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

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

    Science.gov (United States)

    Nemutlu, Emirhan; Gupta, Anu; Zhang, Song; Viqar, Maria; Holmuhamedov, Ekhson; Terzic, Andre; Jahangir, Arshad; Dzeja, Petras

    2015-01-01

    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 vulnerability of aging

  10. 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, L.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

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

    DEFF Research Database (Denmark)

    Haustein, Sonja; Møller, Mette

    2016-01-01

    The use and purchase of electric bicycles (e-bikes) is emerging in many countries. Existing knowledge about changes in cycling patterns and car replacement after gaining e-bike access is limited and partly contradictory. Based on an online survey among e-bike users in Denmark (N = 427), this study...... looked into these effects by differentiating between different segments of e-bike users. We distinguished four age groups as well as three segments based on cycling attitudes and motives for the use and purchase of e-bikes: (1) enthusiastic e-bikers who showed the most positive attitudes towards e......-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...

  12. Climatic Conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle

    Directory of Open Access Journals (Sweden)

    A. Abe-Ouchi

    2007-07-01

    Full Text Available The ice sheet-climate interaction as well as the climatic response to orbital parameters and atmospheric CO2 concentration are examined in order to drive an ice sheet model throughout an ice age cycle. Feedback processes between ice sheet and atmosphere are analyzed by numerical experiments using a high resolution General Circulation Model (GCM under different conditions at the Last Glacial Maximum. Among the proposed processes, the ice albedo feedback, the elevation-mass balance feedback and the desertification effect over the ice sheet were found to be the dominant processes for the ice-sheet mass balance. For the elevation-mass balance feedback, the temperature lapse rate over the ice sheet is proposed to be weaker than assumed in previous studies. Within the plausible range of parameters related to these processes, the ice sheet response to the orbital parameters and atmospheric CO2 concentration for the last glacial/interglacial cycle was simulated in terms of both ice volume and geographical distribution, using a three-dimensional ice-sheet model. Careful treatment of climate-ice sheet feedback is essential for a reliable simulation of the ice sheet changes during ice age cycles.

  13. Differential cognitive effects of cycling versus stretching/coordination training in middle-aged adults.

    Science.gov (United States)

    Hötting, Kirsten; Reich, Barbara; Holzschneider, Kathrin; Kauschke, Katrin; Schmidt, Tobias; Reer, Rüdiger; Braumann, Klaus-Michael; Röder, Brigitte

    2012-03-01

    Physical exercise has been linked to higher cognitive functioning and enhanced brain plasticity in aging humans. The most consistent positive effects have been reported for executive functions associated with frontal brain regions. In rodents, however, running has been shown to induce functional and structural changes in the hippocampus, a brain region known to be important for memory. It is still a matter of debate which cognitive functions are susceptible to exercise and whether an increase in cardiovascular fitness is beneficial for cognitive functioning. Moreover, little is known about the impact of exercise on cognition in middle-aged humans. Sixty-eight sedentary men and women between 40 and 56 years of age were randomly assigned to one of two training programs: aerobic endurance training (cycling) or nonendurance training (stretching/coordination). Both groups exercised twice a week for six months. Additionally, a sedentary control group was tested. At baseline and after six months, episodic memory, perceptual speed, executive functions, and spatial reasoning were assessed with standardized psychometric tests, and all participants underwent a cardiovascular fitness test. Significant improvements in memory were observed in both the cycling and the stretching/coordination group as compared with the sedentary control group. The improvement in episodic memory correlated positively with the increase in cardiovascular fitness. The stretching/coordination training particularly improved selective attention as compared with the cycling training. The results suggest that cardiovascular fitness has beneficial effects even in high-functioning middle-aged participants, but that these benefits are very specific to memory functions rather than a wider range of cognitive functions.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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)

  19. 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.

  20. The Age-Related Performance Decline in Ironman Triathlon Starts Earlier in Swimming Than in Cycling and Running.

    Science.gov (United States)

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

    2018-02-01

    Käch, I, Rüst, CA, Nikolaidis, PT, Rosemann, T, and Knechtle, B. The age-related performance decline in Ironman triathlon starts earlier in swimming than in cycling and running. J Strength Cond Res 32(2): 379-395, 2018-In Ironman triathlon, the number of overall male and female finishers increased in the past 30 years, while an improvement in performance has been reported. Studies concluding these numbers only analyzed the top 10 athletes per age group instead of all finishers; therefore, a selection bias might have occurred. The aim of this 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 analyzed. The number of finishers increased in all age groups with the 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 (from 18-24 to 40-44 years) and older age groups for swimming (from 50-54 to 65-69 years) and cycling (from 35-39 to 55-59 years), whereas it impaired in younger age groups for swimming (from 18-24 to 45-49 years) and cycling (from 18-24 to 30-34 years), and older age groups in running (from 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

  1. 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.

  2. 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. PMID:22523503

  3. The changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men.

    Science.gov (United States)

    Huang, Rui; Zhu, Wei-Jie; Li, Jing; Gu, Yi-Qun

    2014-12-01

    To evaluate the changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men. Point counting method was used to analyze the stereological parameters of Leydig cells. The stage number of seminiferous epithelium cycle was calculated in the same testicular tissue samples which were used for Leydig cell stereological analysis. The aging group had shown more severe pathological changes as well as higher pathologic scores than the young group. Compared with the control group, the volume density (VV) and surface density (NA) of Leydig cells in the aging group were increased significantly. The stage number of seminiferous epithelium cycle in the aging group was decreased coincidently compared to the young group. Leydig cell Vv in the young group has a positive relationship with stages I, II, III, V and VI of seminiferous epithelium cycle, and Leydig cell NA and numerical density (NV) were positively related to stage IV. However, only the correlation between NV and stage II was found in the aging group. The stage number of seminiferous epithelium cycle was decreased in aging testes. Changes in the stage distribution in aging testes were related to the Leydig cell stereological parameters which presented as a sign of morphological changes. Copyright © 2014 Elsevier GmbH. All rights reserved.

  4. Vascular cognitive impairment, dementia, aging and energy demand. A vicious cycle.

    Science.gov (United States)

    Popa-Wagner, A; Buga, Ana-Maria; Popescu, B; Muresanu, D

    2015-08-01

    To a great extent, cognitive health depends on cerebrovascular health and a deeper understanding of the subtle interactions between cerebrovascular function and cognition is needed to protect humans from one of the most devastating affliction, dementia. However, the underlying biological mechanisms are still not completely clear. Many studies demonstrated that the neurovascular unit is compromised in cerebrovascular diseases and also in other types of dementia. The hemodynamic neurovascular coupling ensures a strong increase of the cerebral blood flow (CBF) and an acute increase in neuronal glucose uptake upon increased neural activity. Dysfunction of cerebral autoregulation with increasing age along with age-related structural and functional alterations in cerebral blood vessels including accumulation of amyloid-beta (Aβ) in the media of cortical arterioles, neurovascular uncoupling due to astrocyte endfeet retraction, impairs the CBF and increases the neuronal degeneration and susceptibility to hypoxia and ischemia. A decreased cerebral glucose metabolism is an early event in Alzheimer's disease (AD) pathology and may precede the neuropathological Aβ deposition associated with AD. Aβ accumulation in turn leads to further decreases in the CBF closing the vicious cycle. Alzheimer, aging and diabetes are also influenced by insulin/insulin-like growth factor-1 signaling, and accumulated evidence indicates sporadic AD is associated with disturbed brain insulin metabolism. Understanding how vascular and metabolic factors interfere with progressive loss of functional neuronal networks becomes essential to develop efficient drugs to prevent cognitive decline in elderly.

  5. Sea-level responses to sediment transport over the last ice age cycle

    Science.gov (United States)

    Ferrier, K.; Mitrovica, J. X.

    2013-12-01

    Sea-level changes over the last ice age cycle were instrumental in steering Earth's topographic evolution. These sea-level variations were driven by changes in surface mass loads, including not only ice and ocean mass variations but also the transfer of rock from eroding mountains to sedimentary deposits. Here we use an extended numerical model of ice age sea level (Dalca et al., 2013) to explore how sediment erosion and deposition affected global sea-level variations over the last ice age cycle. The model takes histories of ice and sediment loads as inputs, and it computes gravitationally self-consistent sea level responses by accounting for the deformational, gravitational, and rotational perturbations in the Earth's viscoelastic form. In these model simulations, we use published estimates of erosion rates, sedimentation rates, and ice sheet variations to constrain sediment and ice loading since the Last Interglacial. We explore sea-level responses to several erosional and depositional scenarios, and in each we quantify the relative contributions of crustal deformation and gravitational perturbation to the computed sea-level change. We also present a case study to illustrate the effects that sediment transfer can have on sea level at the regional scale. In particular, we focus on the region surrounding the Indus River, where fluvial sediment fluxes are among the highest on Earth. Preliminary model results suggest that sediment fluxes from Asia to the ocean are large enough to produce a significant response in sea level along the northeastern coast of the Arabian Sea. Moreover, they suggest that modeled sea-level histories are sensitive to the timing and spatial distribution of sediment erosion and deposition. For instance, sediment deposition along the continental shelf - which may have been the primary site of Indus River sediment deposition during the Holocene - produces a different sea-level response than sediment deposition on the deep-sea Indus Fan, where

  6. 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

  7. 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.

  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. Cycling provision separated from motor traffic: a systematic review exploring whether stated preferences vary by gender and age.

    Science.gov (United States)

    Aldred, Rachel; Elliott, Bridget; Woodcock, James; Goodman, Anna

    2017-01-02

    In this paper, we represent a systematic review of stated preference studies examining the extent to which cycle infrastructure preferences vary by gender and by age. A search of online, English-language academic and policy literature was followed by a three-stage screening process to identify relevant studies. We found 54 studies that investigated whether preferences for cycle infrastructure varied by gender and/or by age. Forty-four of these studies considered the extent of separation from motor traffic. The remainder of the studies covered diverse topics, including preferred winter maintenance methods and attitudes to cycle track lighting. We found that women reported stronger preferences than men for greater separation from motor traffic. There was weaker evidence of stronger preferences among older people. Differences in preferences were quantitative rather than qualitative; that is, preferences for separated infrastructure were stronger in some groups than in others, but no group preferred integration with motor traffic. Thus, in low-cycling countries seeking to increase cycling, this evidence suggests focusing on the stronger preferences of under-represented groups as a necessary element of universal design for cycling.

  10. The influence of female age on the cumulative live-birth rate of fresh cycles and subsequent frozen cycles using vitrified blastocysts in hyper-responders.

    Science.gov (United States)

    Wu, Cheng-Hsuan; Lee, Tsung-Hsien; Chen, Hsiu-Hui; Chen, Chung-I; Huang, Chun-Chia; Lee, Maw-Sheng

    2015-10-01

    The aim of this research was to study the influence of female age on the cumulative live-birth rate of fresh and subsequent frozen cycles using vitrified blastocysts of the same cohort in hyper-responders. This was a retrospective study of 1137 infertile women undergoing their first in vitro fertilization treatment between 2006 and 2013. The main outcome measure was cumulative live births among the fresh and all vitrified blastocyst transfers combined after the same stimulation cycle. The results were also analyzed according to age (i.e., live-birth rate was 73.3%. The cumulative live-birth rate declined from 73.9% for women younger than 35 years old to 67.3% for women 35-39 years old to 57.9% for women 40 years or older. Combined fresh and vitrified blastocyst transfer cycles can result in a high cumulative live-birth rate. The cumulative live-birth rates among older women are lower than the rates among younger women when autologous oocytes are used. Copyright © 2015. Published by Elsevier B.V.

  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...

  13. A Method to Teach Age-Specific Demography with Field Grown Rapid Cycling "Brassica rapa" (Wisconsin Fast Plants)

    Science.gov (United States)

    Kelly, Martin G.; Terrana, Sebastian

    2004-01-01

    In this paper, we demonstrate that rapid cycling "Brassica rapa" (Wisconsin Fast Plants) can be used in inquiry-based, student ecological fieldwork. We are the first to describe age-specific survival for field-grown Fast Plants and identify life history traits associated with individual survival. This experiment can be adapted by educators as a…

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

    OpenAIRE

    Hiona, Asimina; Leeuwenburgh, Christiaan

    2007-01-01

    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 mu...

  15. Seasonal Cycle and Relationship of Seasonal Rhino- and Influenza Virus Epidemics With Episodes of Asthma Exacerbation in Different Age Groups.

    Science.gov (United States)

    Lee, Seung Won; Lee, Shinhae; Sheen, Youn Ho; Ha, Eun Kyo; Choi, Sun Hee; Yang, Min Suk; Hwang, Sohyun; Kim, Sung Soon; Choi, Jang Hoon; Han, Man Yong

    2017-11-01

    Seasonal variations in asthma exacerbation (AE) are associated with respiratory virus outbreaks and the return of children to school after vacation. This study aims to elucidate the period, phase, and amplitude of seasonal cycles of AE in 5 different age groups with regard to rhino- and influenza virus epidemics in Korea. The number of daily emergency department (ED) visits for AE in all age groups of Korea and the nationwide weekly incidence of rhino- and influenza virus, were obtained for 2008-2012. Fourier regression was used to model rhythmicity, and the Cosinor method was used to determine the amplitude and phase of the cycles in each age group. The cross-correlation function (CCF) between AE and the rhino- and influenza virus epidemics was also calculated. There were 157,559 events of AE (0.62 events/1,000 individuals/year) during the study period. There were spring and fall peaks of AE in children and adults, but only 1 winter peak in the elderly. The amplitude of the AE peak in infants was higher in spring than in fall (9.16 vs 3.04, Paged ≥60 years (rho=0.682). The rhythmicity, amplitude, and phase of the annual cycle of AE differed among different age groups. The patterns of AE were related to the annual rhino- and influenza virus epidemics.

  16. The duration of a Yellowstone super-eruption cycle and implications for the age of the Olduvai subchron

    Science.gov (United States)

    Rivera, Tiffany A.; Darata, Rachel; Lippert, Peter C.; Jicha, Brian R.; Schmitz, Mark D.

    2017-12-01

    Small-volume rhyolitic eruptions preceding and following a caldera-forming eruption can provide insights into the tempo of eruption cycles and timing of magmatic recharge. In this contribution, high-precision 40Ar/39Ar eruption ages were obtained on the three effusive eruptions bracketing the Huckleberry Ridge Tuff, which comprise Yellowstone's first volcanic cycle. These dates are supplemented with detailed paleomagnetic and rock magnetic analyses to resolve discrepancies with previous reported stratigraphy. The Huckleberry Ridge Tuff (2.08 Ma) was preceded by an eruption at 2.14 Ma, and followed by eruptions at 1.98 and 1.95 Ma, all of which occurred during four distinct periods of geomagnetic instability within the Matuyama chron. The first volcanic cycle of Yellowstone has now been constrained to within a 200 kyr timespan, or half of the previously proposed duration, and similar to the duration of volcanic activity for caldera-forming systems in the Jemez Volcanic Field. The maximum duration for magmatic recharge for the first Yellowstone volcanic cycle is no greater than 100 kyr, and likely closer to 40 kyr. Furthermore, the combined 40Ar/39Ar eruption ages and paleomagnetic results provide polarity anchors for the Pre-Olduvai excursion and Olduvai subchron, which are often used as tie-points in studies of early Pleistocene hominin evolution.

  17. 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.

    2012-01-01

    This article 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 a 1-year higher average age

  18. 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.

    2012-01-01

    This article 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 a 1-year higher average age

  19. Comparison between jumping vs. cycling tests of short-term power in elite male handball players: the effect of age

    OpenAIRE

    Nikolaidis, Pantelis Theodoros; Torres-Luque, Gema; Chtourou, Hamdi; Clemente Suárez, Vicente Javier; Ramírez-Vélez, Robinson; Heller, Jan

    2016-01-01

    Purpose: The aim of the present study was to examine the effect of age on the relationship between jumping and cycling tests of short-term power in team handball (TH) players. Methods: A cross-sectional study was conducted, in which adolescent and adult TH players (n = 96, age 19.6 ± 6.9 yrs, body mass 75.8 ± 14.1 kg, height 1.78 ± 0.10, mean ± standard deviation) performed four jumping tests (i.e., squat jump, countermovement jump, Abalakov jump and a 30-s Bosco test), and two...

  20. 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

  1. 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.

  2. Single-cell RNA-seq reveals changes in cell cycle and differentiation programs upon aging of hematopoietic stem cells

    Science.gov (United States)

    Kowalczyk, Monika S.; Tirosh, Itay; Heckl, Dirk; Rao, Tata Nageswara; Dixit, Atray; Haas, Brian J.; Schneider, Rebekka K.; Wagers, Amy J.; Ebert, Benjamin L.; Regev, Aviv

    2015-01-01

    Both intrinsic cell state changes and variations in the composition of stem cell populations have been implicated as contributors to aging. We used single-cell RNA-seq to dissect variability in hematopoietic stem cell (HSC) and hematopoietic progenitor cell populations from young and old mice from two strains. We found that cell cycle dominates the variability within each population and that there is a lower frequency of cells in the G1 phase among old compared with young long-term HSCs, suggesting that they traverse through G1 faster. Moreover, transcriptional changes in HSCs during aging are inversely related to those upon HSC differentiation, such that old short-term (ST) HSCs resemble young long-term (LT-HSCs), suggesting that they exist in a less differentiated state. Our results indicate both compositional changes and intrinsic, population-wide changes with age and are consistent with a model where a relationship between cell cycle progression and self-renewal versus differentiation of HSCs is affected by aging and may contribute to the functional decline of old HSCs. PMID:26430063

  3. 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

  4. Pension funds’ asset allocation and participant age: a test of the life-cycle model

    NARCIS (Netherlands)

    Bikker, J.A.|info:eu-repo/dai/nl/06912261X; Broeders, D.W.G.A; Hollanders, D. A.; Ponds, E. H.M.

    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

  5. 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 (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

  6. 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 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.

  7. Menstrual cycle and detectable human papillomavirus in reproductive-age women: a time series study.

    Science.gov (United States)

    Liu, Su-Hsun; Brotman, Rebecca M; Zenilman, Jonathan M; Gravitt, Patti E; Cummings, Derek A T

    2013-11-01

    Current evidence on the relationship between human papillomavirus (HPV) DNA detection and menstrual cycle has been inconsistent. We included 21 nonoral contraceptive pill (non-OCP) users who self-collected vaginal samples twice per week for 16 weeks. We explored whether variable detection of HPV DNA exhibited cyclic or other structured temporal patterns. We also evaluated relationships between serial HPV prevalence, sexual behavior, and suspected bacterial vaginosis (BV) as defined by Nugent Gram stain score ≥7. During follow-up, any-type HPV prevalence varied between 61.1% and 85.0%. Although not statistically significant, we observed a maximum autocorrelation in serial HPV prevalence lagging 14 days (correlation coefficient [ρ], -0.24). Any-type HPV detection had a periodic behavior, generally repeating every 28.0 days (bootstrapped interquartile range, 22.4-28.0) and peaking around the ovulation time (adjusted odds ratio, 1.96; 95% confidence interval [CI], 1.06-3.62) as compared to menstruation. We also showed that an increase in any-type HPV prevalence preceded the beginning of a menstrual cycle by 9-12 days. There was no evidence of relationships between HPV prevalence and sexual activity or Nugent score. Serially detected any-type HPV DNA showed a periodic behavior and was likely to peak in the periovulatory phase among non-OCP users.

  8. RELIABILITY AND VALIDITY OF PHYSIOLOGICAL DATA OBTAINED WITHIN A CYCLE-RUN TRANSITION TEST IN AGE-GROUP TRIATHLETES

    Directory of Open Access Journals (Sweden)

    Veronica Vleck

    2012-12-01

    Full Text Available This study examined the validity and reliability of a sequential "Run-Bike-Run" test (RBR in age-group triathletes. Eight Olympic distance (OD specialists (age 30.0 ± 2.0 years, mass 75.6 ± 1.6 kg, run VO2max 63.8 ± 1.9 ml·kg-1·min-1, cycle VO2peak 56.7 ± 5.1 ml·kg-1·min-1 performed four trials over 10 days. Trial 1 (TRVO2max was an incremental treadmill running test. Trials 2 and 3 (RBR1 and RBR2 involved: 1 a 7-min run at 15 km·h-1 (R1 plus a 1-min transition to 2 cycling to fatigue (2 W·kg-1 body mass then 30 W each 3 min; 3 10-min cycling at 3 W·kg-1 (Bsubmax; another 1-min transition and 4 a second 7-min run at 15 km·h-1 (R2. Trial 4 (TT was a 30-min cycle - 20-min run time trial. No significant differences in absolute oxygen uptake (VO2, heart rate (HR, or blood lactate concentration ([BLA] were evidenced between RBR1 and RBR2. For all measured physiological variables, the limits of agreement were similar, and the mean differences were physiologically unimportant, between trials. Low levels of test-retest error (i.e. ICC <0.8, CV<10% were observed for most (logged measurements. However [BLA] post R1 (ICC 0.87, CV 25.1%, [BLA] post Bsubmax (ICC 0.99, CV 16.31 and [BLA] post R2 (ICC 0.51, CV 22.9% were least reliable. These error ranges may help coaches detect real changes in training status over time. Moreover, RBR test variables can be used to predict discipline specific and overall TT performance. Cycle VO2peak, cycle peak power output, and the change between R1 and R2 (deltaR1R2 in [BLA] were most highly related to overall TT distance (r = 0.89, p < 0. 01; r = 0.94, p < 0.02; r = 0.86, p < 0.05, respectively. The percentage of TR VO2max at 15 km·h-1, and deltaR1R2 HR, were also related to run TT distance (r = -0.83 and 0.86, both p < 0.05

  9. Nanocomposite containing CaF2 nanoparticles: Thermal cycling, wear and long-term water-aging

    Science.gov (United States)

    Weir, Michael D.; Moreau, Jennifer L.; Levine, Eric D.; Strassler, Howard D.; Chow, Laurence C.; Xu, Hockin H. K.

    2012-01-01

    Objectives Fluoride (F) releasing dental restoratives are promising to promote remineralization and combat caries. The objectives of this study were to develop nanocomposite containing calcium fluoride nanoparticles (nCaF2), and to investigate the long-term mechanical durability including wear, thermal-cycling and long-term water-aging behavior. Methods Two types of fillers were used: nCaF2 with a diameter of 53 nm, and glass particles of 1.4 μm. Four composites were fabricated with fillers of: (1) 0% nCaF2 + 65% glass; (2) 10% nCaF2 + 55% glass; (3) 20% nCaF2 + 45% glass; (4) 30% nCaF2 + 35% glass. Three commercial materials were also tested. Specimens were subjected to thermal-cycling between 5 °C and 60 °C for 105 cycles, three-body wear for 4×105 cycles, and water-aging for 2 years. Results After thermal-cycling, the nCaF2 nanocomposites had flexural strengths in the range of 100-150 MPa, five times higher than the 20-30 MPa for resin-modified glass ionomer (RMGI). The wear scar depth showed an increasing trend with increasing nCaF2 filler level. Wear of nCaF2 nanocomposites was within the range of wear for commercial controls. Water-aging decreased the strength of all materials. At 2 years, flexural strength was 94 MPa for nanocomposite with 10% nCaF2, 60 MPa with 20% nCaF2, and 48 MPa with 30% nCaF2. They are 3-6 fold higher than the 15 MPa for RMGI (p nanocomposites appeared dense and solid. Significance Combining nCaF2 with glass particles yielded nanocomposites with long-term mechanical properties that were comparable to those of a commercial composite with little F release, and much better than those of RMGI controls. These strong long-term properties, together with their F release being comparable to RMGI as previously reported, indicate that the nCaF2 nanocomposites are promising for load-bearing and caries-inhibiting restorations. PMID:22429937

  10. Sex and age differences in mass, morphology, and annual cycle in European ground squirrels, Spermophilus citellus

    NARCIS (Netherlands)

    Millesi, E; Strijkstra, AM; Hoffmann, IE; Dittami, JP; Daan, S

    We collected 6 years of data (1990-1995) on survival, hibernation, body-mass changes, and morphological parameters for a suburban population of European ground squirrels (Spermophilus citellus) using censusing and capture-recapture techniques. We attempted to determine differences in sex and age in

  11. 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

  12. 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

  13. The muddle of ages, turnover, transit, and residence times in the carbon cycle.

    Science.gov (United States)

    Sierra, Carlos A; Müller, Markus; Metzler, Holger; Manzoni, Stefano; Trumbore, Susan E

    2017-05-01

    Comparisons among ecosystem models or ecosystem dynamics along environmental gradients commonly rely on metrics that integrate different processes into a useful diagnostic. Terms such as age, turnover, residence, and transit times are often used for this purpose; however, these terms are variably defined in the literature and in many cases, calculations ignore assumptions implicit in their formulas. The aim of this opinion piece was i) to make evident these discrepancies and the incorrect use of formulas, ii) highlight recent results that simplify calculations and may help to avoid confusion, and iii) propose the adoption of simple and less ambiguous terms. © 2016 John Wiley & Sons Ltd.

  14. Proactive pressure relief system management of life cycle and ageing in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kolenc, J. [Farris Engineering, Edmonton, Alberta (Canada); Ferrar, S. [Farris Engineering, Brantford, Ontario (Canada)

    2011-07-01

    The last major power nuclear station built in North America was built when the Altair Company introduced the first microcomputer sparking the PC frenzy. It is safe to assume that there have been a great many changes since 1977 on both accounts. As the world's aging nuclear plants continue to be challenged with maintenance and replacement issues (obsolescence), as well making improvements within their facilities, proper pressure relief system management looms as a growing concern. This problem grows more acute as new engineering best practices are promulgated across industries and regulatory standards become more rigorous with much stricter enforcements. Unlike most pieces of operating equipment in a nuclear facility, pressure relief devices demand an extra level of consideration; as they form the 'last line of defense'. Combine the on-going obsolescence issue, with today's ever increasing demands for overall plant and public safety; pressure relief safety management will require increasing 'proactive' efforts to ensure safe facilities. This paper has been written to address some global pressure relief system management issues with respect the worlds aging nuclear facilities. This paper reflects findings we have discovered while conducting engineering pressure relief system audits on various nuclear power stations. It should be noted that these finding are not atypical of similar findings in pressure relief systems in the hydrocarbon processing world. (author)

  15. Dynamic strain ageing evidences during low cycle fatigue deformation in ferritic martensitic stainless steels

    Science.gov (United States)

    Armas, A. F.; Avalos, M.; Alvarez-Armas, I.; Petersen, C.; Schmitt, R.

    1998-10-01

    The influence of dynamic strain ageing (DSA) on the strain cyclic behaviour of ferrite-martensite stainless steels was investigated at temperatures ranging from room temperature to 823 K. For fully annealed AISI 420 initial hardening followed by a saturation stage was observed at each test temperature. This steel was found to be susceptible to DSA as evidenced by the temperature independent stress saturation observed between 523 and 723 K. Normalized and tempered MANET II and F82H mod. softens during cyclic loading at all temperatures. In this steel DSA manifestations were observed on plotting the peak tensile stress difference between hysteresis loops obtained at different strain rates. Strongly abnormal behaviour with higher peak tensile stresses corresponding to slower strain rates was observed in the temperature range between 500 and 700 K. It is proposed that DSA mechanisms caused by the drag of solution carbon atoms is responsible for this unusual behaviour.

  16. 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

  17. Alterations in purine metabolism in middle-aged elite, amateur, and recreational runners across a 1-year training cycle.

    Science.gov (United States)

    Zieliński, Jacek; Kusy, Krzysztof; Słomińska, Ewa

    2013-03-01

    Changes in purine derivatives may be considered as signs of training-induced metabolic adaptations. The purpose of this study was to assess the effect of a 1-year training cycle on the response of hypoxanthine (Hx) concentration and Hx-guanine phosphoribosyltransferase (HGPRT) activity. Three groups of middle-aged male runners were examined: 11 elite master runners (EL; 46.0 ± 3.8 years), 9 amateur runners (AM; 45.1 ± 4.7 years), and 10 recreational runners (RE; 45.9 ± 6.1 years). Plasma Hx concentration and erythrocyte HGPRT activity were measured in three characteristic training phases of the annual cycle. Significant differences in post-exercise Hx concentration and resting HGPRT activity were demonstrated between the EL, AM, and RE groups across consecutive training phases. The EL group showed lowest Hx concentration and highest HGPRT activity compared to the AM and RE groups. Analogous differences were observed between the AM and RE groups during specific preparation. For the EL group, the changes were observed across all examinations and the lowest Hx concentration and highest HGPRT activity were found in the competition phase. Significant change was also revealed in the AM group between the general and specific preparation, but not in the competition phase. No significant changes were found in the RE runners who did not use anaerobic exercise in their training. In conclusion, a long-lasting endurance training, incorporating high-intensity exercise, results in significant changes in purine metabolism, whereas training characterized by constant low-intensity exercise does not. Plasma Hx concentration and erythrocyte HGPRT activity may be sensitive indicators of training adaptation and training status in middle-aged athletes.

  18. 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

  19. Stability and fragmentation of the activity rhythm across the sleep-wake cycle: The importance of age, lifestyle and mental health

    NARCIS (Netherlands)

    Luik, A.I.; Zuurbier, L.A.; Hofman, A.; van Someren, E.J.W.; Tiemeier, H.

    2013-01-01

    The rhythms of activity across the 24-h sleep-wake cycle, determined in part by the circadian clock, change with aging. Few large-scale studies measured the activity rhythm objectively in the general population. The present population-based study in middle-aged and elderly persons evaluated how

  20. Pregnancy outcomes decline in recipients over age 44: an analysis of 27,959 fresh donor oocyte in vitro fertilization cycles from the Society for Assisted Reproductive Technology.

    Science.gov (United States)

    Yeh, Jason S; Steward, Ryan G; Dude, Annie M; Shah, Anish A; Goldfarb, James M; Muasher, Suheil J

    2014-05-01

    To use a large and recent national registry to provide an updated report on the effect of recipient age on the outcome of donor oocyte in vitro fertilization (IVF) cycles. Retrospective cohort study. United States national registry for assisted reproductive technology. Recipients of donor oocyte treatment cycles between 2008 and 2010, with cycles segregated into five age cohorts: ≤34, 35 to 39, 40 to 44, 45 to 49, and ≥50 years. None. Implantation, clinical pregnancy, live-birth, and miscarriage rates. In donor oocyte IVF cycles, all age cohorts ≤39 years had similar rates of implantation, clinical pregnancy, and live birth when compared with the 40- to 44-year-old reference group. Patients in the two oldest age groups (45 to 49, ≥50 years) experienced statistically significantly lower rates of implantation, clinical pregnancy, and live birth compared with the reference group. Additionally, all outcomes in the ≥50-year-old group were statistically significantly worse than the 45- to 49-year-old group, demonstrating progressive decline with advancing age. Recent national registry data suggest that donor oocyte recipients have stable rates of pregnancy outcomes before age 45, after which there is a small but steady and significant decline. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  1. 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

    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...... 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...

  2. Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

    Directory of Open Access Journals (Sweden)

    D. Baggenstos

    2017-07-01

    Full Text Available Old ice for paleo-environmental studies, traditionally accessed through deep core drilling on domes and ridges on the large ice sheets, can also be retrieved at the surface from ice sheet margins and blue ice areas. The practically unlimited amount of ice available at these sites satisfies a need in the community for studies of trace components requiring large sample volumes. For margin sites to be useful as ancient ice archives, the ice stratigraphy needs to be understood and age models need to be established. We present measurements of trapped gases in ice from Taylor Glacier, Antarctica, to date the ice and assess the completeness of the stratigraphic section. Using δ18O of O2 and methane concentrations, we unambiguously identify ice from the last glacial cycle, covering every climate interval from the early Holocene to the penultimate interglacial. A high-resolution transect reveals the last deglaciation and the Last Glacial Maximum (LGM in detail. We observe large-scale deformation in the form of folding, but individual stratigraphic layers do not appear to have undergone irregular thinning. Rather, it appears that the entire LGM–deglaciation sequence has been transported from the interior of the ice sheet to the surface of Taylor Glacier relatively undisturbed. We present an age model that builds the foundation for gas studies on Taylor Glacier. A comparison with the Taylor Dome ice core confirms that the section we studied on Taylor Glacier is better suited for paleo-climate reconstructions of the LGM due to higher accumulation rates.

  3. Modeling Reveals the Role of Aging and Glucose Uptake Impairment in L1A1 Listeria monocytogenes Biofilm Life Cycle

    Directory of Open Access Journals (Sweden)

    Eva Balsa-Canto

    2017-11-01

    Full Text Available Listeria monocytogenes is a food-borne pathogen that can persist in food processing plants by forming biofilms on abiotic surfaces. The benefits that bacteria can gain from living in a biofilm, i.e., protection from environmental factors and tolerance to biocides, have been linked to the biofilm structure. Different L. monocytogenes strains build biofilms with diverse structures, and the underlying mechanisms for that diversity are not yet fully known. This work combines quantitative image analysis, cell counts, nutrient uptake data and mathematical modeling to provide a mechanistic insight into the dynamics of the structure of biofilms formed by L. monocytogenes L1A1 (serotype 1/2a strain. Confocal laser scanning microscopy (CLSM and quantitative image analysis were used to characterize the structure of L1A1 biofilms throughout time. L1A1 forms flat, thick structures; damaged or dead cells start appearing early in deep layers of the biofilm and rapidly and massively loss biomass after 4 days. We proposed several reaction-diffusion models to explain the system dynamics. Model candidates describe biomass and nutrients evolution including mechanisms of growth and cell spreading, nutrients diffusion and uptake and biofilm decay. Data fitting was used to estimate unknown model parameters and to choose the most appropriate candidate model. Remarkably, standard reaction-diffusion models could not describe the biofilm dynamics. The selected model reveals that biofilm aging and glucose impaired uptake play a critical role in L1A1 L. monocytogenes biofilm life cycle.

  4. Study on Dynamic Strain Aging and Low-Cycle Fatigue of Stainless Steel in Ultra-Supercritical Unit

    Science.gov (United States)

    Hongwei, Zhou; Yizhu, He; Jizu, Lv; Sixian, Rao

    Dynamic strain aging (DSA) and low-cycle fatigue (LCF) behavior of TP347H stainless steel in ultra-supercritical unit were investigated at 550-650 °C. All the LCF tests were carried out under a fully-reversed, total axial strain control mode at the total strain amplitude from ±0.2% to ±1.0%. The effects of DSA in cyclic stress response, microstructure evolution and fatigue fracture surfaces and fatigue life were investigated in detail. The results show that DSA occurs during tensile, which is manifested as serrated flow in tensile stress-strain curves. The apparent activation energy for appearing of serrations in tensile stress-strain curves was 270 kJ/mol. Pipe diffusion of substitutional solutes such as Cr and Nb along the dislocation core, and strong interactions between segregated solutes and dislocations are considered as the mechanism of DSA. DSA partly restricts dislocation cross-slip, and dislocation cross-slip and planar-slip happen simultaneously during LCF. A lot of planar structures form, which is due to dislocation gliding on the special plane. This localized deformation structures result in many crack initiation sites. Meanwhile, DSA hardening increases cyclic stress response, accelerating crack propagation, which reduces high temperature strain fatigue life of steel.

  5. A life cycle costing approach for discounting in age and interval replacement optimisation models for civil infrastructure assets

    NARCIS (Netherlands)

    van den Boomen, M.; Schoenmaker, R.; Wolfert, A.R.M.

    2017-01-01

    Civil infrastructure assets, such as roads, locks, bridges, treatment plants and storm surge barriers, are often characterised by long service lives and corresponding technical life cycles. When life cycles are long, the time value of money plays a role in asset management decision-making on capital

  6. 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.

  7. Differences in the acute inflammatory and glucose regulatory responses between small-sided games and cycling in sedentary, middle-aged men.

    Science.gov (United States)

    Mendham, Amy E; Duffield, Rob; Marino, Frank; Coutts, Aaron J

    2015-11-01

    This study compared the acute inflammatory and glucose regulatory response within and between rugby specific small-sided games and stationary cycling in sedentary, middle-aged Caucasian men. Nine middle-aged, sedentary men who were free from disease participated in 2 × 40 min exercise conditions (stationary cycling and small-sided games) in a randomised, cross-over design. Heart rate and Rating of Perceived Exertion were collected during each bout. Venous blood was collected at fasting, 0, 30, 60 and 240 min post-exercise for measurement of glucose, insulin, cortisol and inflammatory markers including tumour necrosis factor-α, interleukin-1 β, interleukin-6, interleukin-1 receptor agonist and C-reactive protein. No significant differences existed between conditions for heart rate and Rating of Perceived Exertion (p > 0.05). Interleukin-6 was increased immediately post-exercise in both conditions (p small-sided games at 240 min post-exercise compared with stationary cycling (p small-sided games than stationary cycling at 30 and 240 min post-exercise (p 0.05). Results for C-reactive protein, tumour necrosis factor-α and interleukin-1 β showed no significant exercise-induced changes within or between conditions (p > 0.05). Both small-sided games and stationary cycling conditions were sufficient to stimulate an acute anti-inflammatory response as indicated by the post-exercise elevation of interleukin-6, interleukin-1 receptor agonist and cortisol. The novel findings are that an acute bout of small-sided games bout is capable of maintaining an elevated post-exercise interleukin-6 response and lowered blood glucose concentration, compared with intensity- and duration-matched stationary cycling condition. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  8. Combined advanced parental age has an additive negative effect on live birth rates-data from 4057 first IVF/ICSI cycles.

    Science.gov (United States)

    McPherson, Nicole O; Zander-Fox, Deirdre; Vincent, Andrew D; Lane, Michelle

    2017-10-04

    The purpose of this study is to determine if there is an additive effect of combined advanced maternal and paternal age on pregnancy and live birth rates. Retrospective data analysis of 4057 first cycles at a fertility centre between 2009 and 2013 was compiled. Donor, preimplantation genetic screening and double embryo transfer cycles were excluded. Main outcomes measured were clinical pregnancy, viable pregnancy, live birth and term birth. Logistic regression indicated strong negative associations for maternal ages exceeding 27 years with clinical pregnancies (p < 0.001), viable pregnancies (p < 0.001), live births (p < 0.001) and term births (p < 0.001). There was evidence of negative associations between paternal age and both viable pregnancies (p = 0.06) and live births (p = 0.04), such that the probability of pregnancy was 10% further reduced for women who were 35 years with a partner over 40 years vs. women aged 35 years with a partner under 30 years. There was evidence of an interaction between maternal age and the paternal age on term births (p = 0.02) such that advanced paternal age's effect on the probability of a term birth was only evident in couples where the maternal age ranged between ~27 and 35 years. There is an additive effect to pregnancy and live birth rates when both partners are of an advanced age, thus highlighting the need for pre-conception public health messaging and a combined approach to ART counselling assessing both parental ages in combination.

  9. Cell cycle-related genes as modifiers of age of onset of colorectal cancer in Lynch syndrome: a large-scale study in non-Hispanic white patients.

    Science.gov (United States)

    Chen, Jinyun; Pande, Mala; Huang, Yu-Jing; Wei, Chongjuan; Amos, Christopher I; Talseth-Palmer, Bente A; Meldrum, Cliff J; Chen, Wei V; Gorlov, Ivan P; Lynch, Patrick M; Scott, Rodney J; Frazier, Marsha L

    2013-02-01

    Heterogeneity in age of onset of colorectal cancer in individuals with mutations in DNA mismatch repair genes (Lynch syndrome) suggests the influence of other lifestyle and genetic modifiers. We hypothesized that genes regulating the cell cycle influence the observed heterogeneity as cell cycle-related genes respond to DNA damage by arresting the cell cycle to provide time for repair and induce transcription of genes that facilitate repair. We examined the association of 1456 single nucleotide polymorphisms (SNPs) in 128 cell cycle-related genes and 31 DNA repair-related genes in 485 non-Hispanic white participants with Lynch syndrome to determine whether there are SNPs associated with age of onset of colorectal cancer. Genotyping was performed on an Illumina GoldenGate platform, and data were analyzed using Kaplan-Meier survival analysis, Cox regression analysis and classification and regression tree (CART) methods. Ten SNPs were independently significant in a multivariable Cox proportional hazards regression model after correcting for multiple comparisons (P Lynch syndrome.

  10. Aging precursors and degradation effects of SiC-MOSFET modules under highly accelerated power cycling conditions

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

    2017-01-01

    A highly accelerated power cycling test platform using current source converter for SiC-MOSFET power modules is proposed. The control principles of delta and average junction temperatures are introduced. By using isolated thermal fibers, the junction temperature (Tj) variations can be monitored...... during the test process without removal of silicone gel. The power module is tested in the conditions of ΔTj=60 °C, mean temperature Tjm=145 °C and the maximum Tj=175 °C. By means of device analyzer, the degraded conditions of electrical parameters after power cycling test are fully investigated...

  11. Race/ethnic disparities in reproductive age: an examination of ovarian reserve estimates across four race/ethnic groups of healthy, regularly cycling women.

    Science.gov (United States)

    Bleil, Maria E; Gregorich, Steven E; Adler, Nancy E; Sternfeld, Barbara; Rosen, Mitchell P; Cedars, Marcelle I

    2014-01-01

    To determine whether reproductive age, as indexed by a validated marker of ovarian reserve (antimüllerian hormone [AMH]), varies among women of different race/ethnic backgrounds. Cross-sectional study. Community-based sample. Multiethnic sample of 947 (277 white, 237 African American, 220 Latina, and 213 Chinese) healthy and regularly cycling premenopausal women, ages 25-45. None. AMH level. A multivariate model was fit examining race/ethnicity, covariates, nonlinear terms for age (age(2), age(3)), and body mass index (BMI(2), BMI(3)), and two-way interactions between race/ethnicity and each of the other predictor variables in relation to AMH. After backward elimination, significant effects included race/ethnicity (F = 8.45), age (F = 349.94), race/ethnicity-by-linear age interaction (F = 4.67), age(2) (F = 31.61), and BMI (F = 10.69). Inspection of the significant race/ethnicity-by-linear age interaction showed AMH levels were consistently lower among Latina women compared with white women across all ages, whereas AMH levels were lower among African American and Chinese women compared with the white women at younger and middle ages, respectively. The AMH levels were higher among African American compared with Latina and Chinese women at older ages. Although the results must be considered preliminary, the findings are twofold: African American women may have lower AMH levels at younger ages but experience less of a reduction in AMH with advancing age, and Latina and Chinese women compared with white women may have lower AMH levels, marking a lower ovarian reserve and a possibly increased risk for earlier menopause. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  12. Aging precursors and degradation effects of SiC-MOSFET modules under highly accelerated power cycling conditions

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

    2017-01-01

    during the test process without removal of silicone gel. The power module is tested in the conditions of ΔTj=60 °C, mean temperature Tjm=145 °C and the maximum Tj=175 °C. By means of device analyzer, the degraded conditions of electrical parameters after power cycling test are fully investigated...

  13. Die degradation effect on aging rate in accelerated cycling tests of SiC power MOSFET modules

    DEFF Research Database (Denmark)

    Luo, Haoze; Baker, Nick; Iannuzzo, Francesco

    2017-01-01

    In order to distinguish the die and bond wire degradations, in this paper both the die and bond wire resistances of SiC MOSFET modules are measured and tested during the accelerated cycling tests. It is proved that, since the die degradation under specific conditions increases the temperature swing...

  14. 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. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. 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.

  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. Strong Gradients in Forest Sensitivity to Climate Change Revealed by Dynamics of Forest Fire Cycles in the Post Little Ice Age Era

    Science.gov (United States)

    Drobyshev, Igor; Bergeron, Yves; Girardin, Martin P.; Gauthier, Sylvie; Ols, Clémentine; Ojal, John

    2017-10-01

    The length of the fire cycle is a critical factor affecting the vegetation cover in boreal and temperate regions. However, its responses to climate change remain poorly understood. We reanalyzed data from earlier studies of forest age structures at the landscape level, in order to map the evolution of regional fire cycles across Eastern North American boreal and temperate forests, following the termination of the Little Ice Age (LIA). We demonstrated a well-defined spatial pattern of post-LIA changes in the length of fire cycles toward lower fire activity during the 1800s and 1900s. The western section of Eastern North America (west of 77°W) experienced a decline in fire activity as early as the first half of the 1800s. By contrast, the eastern section showed these declines as late as the early 1900s. During a regionally fire-prone period of the 1910s-1920s, forests in the western section of Eastern boreal North America burned more than forests in the eastern section. The climate appeared to dominate over vegetation composition and human impacts in shaping the geographical pattern of the post-LIA change in fire activity. Changes in the atmospheric circulation patterns following the termination of the LIA, specifically changes in Arctic Oscillation and the strengthening of the Continental Polar Trough, were likely drivers of the regional fire dynamics.

  18. Stability and fragmentation of the activity rhythm across the sleep-wake cycle: the importance of age, lifestyle, and mental health.

    Science.gov (United States)

    Luik, Annemarie I; Zuurbier, Lisette A; Hofman, Albert; Van Someren, Eus J W; Tiemeier, Henning

    2013-12-01

    The rhythms of activity across the 24-h sleep-wake cycle, determined in part by the circadian clock, change with aging. Few large-scale studies measured the activity rhythm objectively in the general population. The present population-based study in middle-aged and elderly persons evaluated how activity rhythms change with age, and additionally investigated sociodemographics, mental health, lifestyle, and sleep characteristics as determinants of rhythms of activity. Activity rhythms were measured objectively with actigraphy. Recordings of at least 96 h (138 ± 14 h, mean ± SD) were collected from 1734 people (age: 62 ± 9.4 yrs) participating in the Rotterdam Study. Activity rhythms were quantified by calculating interdaily stability, i.e., the stability of the rhythm over days, and intradaily variability, i.e., the fragmentation of the rhythm relative to its 24-h amplitude. We assessed age, gender, presence of a partner, employment, cognitive functioning, depressive symptoms, body mass index (BMI), coffee use, alcohol use, and smoking as determinants. The results indicate that older age is associated with a more stable 24-h activity profile (β = 0.07, p = 0.02), but also with a more fragmented distribution of periods of activity and inactivity (β = 0.20, p health issues in old age.

  19. Thallium 2223 high Tc superconductor in a silver matrix and its magnetic shielding, hermal cycle and time aging properties

    Energy Technology Data Exchange (ETDEWEB)

    Fei, X.; He, W.S.; Havenhill, A. [and others

    1994-12-31

    Superconducting Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Tl2223) was ground to powder. Mixture with silver powder (0--80% weight) and press to desired shape. After proper annealing, one can get good silver-content Tl2223 bulk superconductor. It is time-stable and has good superconducting property as same as pure Tl2223. It also has better mechanical property and far better thermal cycle property than pure Tl2223.

  20. Dynamic strain aging in the high-temperature low-cycle fatigue of SA508 Cl. 3 forging steel

    Science.gov (United States)

    Lee, Byung Ho; Kim, In Sup

    1995-10-01

    The effect of dynamic strain aging on cyclic stress response and fatigue resistance of ASME SA508 Cl.3 forging steel for nuclear reactor pressure vessels has been evaluated in the temperature range of room temperature to 500°C. Total strain ranges and strain rates were varied from 0.7 to 2.0% and from 4 × 10 -4 to 1 × 10 -2 s -1, respectively. The cyclic stress response depended on the testing temperature, strain rate, and range. Generally, the initial cyclic hardening was immediately followed by cyclic softening at all strain rates. However, at 300°C, the operating temperature of nuclear reactor pressure vessels, the variation of cyclic stress amplitude showed the primary and secondary hardening stages dependent on the strain rate and strain range. Dynamic strain aging was manifested by enhanced cyclic hardening, distinguished secondary hardening, and negative strain rate sensitivity. A modified cell shutting model was described for the onset of the secondary hardening due to the dynamic strain aging and it was in good agreement with the experimental results. Fatigue life increased in strain rate at all testing temperatures. Specifically the fatigue life was longer at the dynamic strain aging temperature. Further, the dynamic strain aging was easy to initiate the crack, while crack propagation was retarded by crack branching and suppression of plastic zone, hence the dynamic strain aging caused the improvement of fatigue resistance.

  1. Effects of caffeine on daytime recovery sleep: A double challenge to the sleep-wake cycle in aging.

    Science.gov (United States)

    Carrier, Julie; Paquet, Jean; Fernandez-Bolanos, Marta; Girouard, Laurence; Roy, Joanie; Selmaoui, Brahim; Filipini, Daniel

    2009-10-01

    Caffeine is the most widely used stimulant to counteract the effects of sleepiness, but it also produces important detrimental effects on subsequent sleep, especially when sleep is initiated at a time when the biological clock sends a strong waking signal such as during daytime. This study compares the effects of caffeine on daytime recovery sleep in young (20-30 y.) and middle-aged subjects (45-60 y.). Subjects participated in both caffeine (200mg) and placebo conditions (double-blind cross-over design), spaced one month apart. For each condition, subjects initially came to the laboratory for a nocturnal sleep episode. Daytime recovery sleep started in the morning after 25h of wakefulness. Subjects were administered either one caffeine (100mg) or placebo capsule three hours before daytime recovery sleep and the remaining dose one hour before daytime recovery sleep. Middle-aged subjects showed greater decrements of sleep duration and sleep efficiency than young subjects during daytime recovery under placebo compared to nocturnal sleep. Caffeine decreased sleep efficiency, sleep duration, slow-wave sleep (SWS) and REM sleep during daytime recovery sleep similarly in both age groups. Caffeine also reduced N-REM sleep EEG synchronization during daytime recovery sleep (reduced delta, theta, and alpha power, and greater beta power). The combined influence of age and caffeine made the sleep of middle-aged subjects particularly vulnerable to the circadian waking signal. We propose that lower brain synchronization due to age and caffeine produces greater difficulty in overriding the circadian waking signal during daytime sleep and leads to fragmented sleep. These results have implications for the high proportion of the population using caffeine to cope with night work and jet lag, particularly the middle-aged.

  2. Evaluation of endometrial and subendometrial vascularization and endometrial volume by 3-D power Doppler ultrasound and its relationship with age and pregnancy in intrauterine insemination cycles.

    Science.gov (United States)

    Engels, V; Sanfrutos, L; Pérez-Medina, T; Álvarez, P; Zapardiel, I; Bueno, B; Godoy-Tundidor, S; Bajo-Arenas, J M

    2011-01-01

    To measure endometrial volume and endometrial-subendometrial vascularization by 3-D power Doppler ultrasound in patients undergoing cycles of artificial insemination with ovarian stimulation, to evaluate their relationship with patients' age and pregnancy development. We included patients with primary and secondary infertility of one year of evolution. We measured vascular indexes and endometrial volume by 3-D power Doppler ultrasound. Seventy-nine consecutive cycles were studied. Endometrial volume average was 4.7 ± 2.66 ml. We did not find any difference between the endometrial volumes in women who did versus did not become pregnant (9 vs. 70 women, respectively). The endometrial vascular index was significantly higher in patients aged between 31 and 33 years old. In patients between the ages of 31 and 33, both the endometrial flow index (FI; p = 0.017) and the endometrial vascular FI (p = 0.013) were higher. At the subendometrial area, the vascular FI was lower in women older than 33 years old (p = 0.024), while the FI was higher in patients that achieved pregnancy (p = 0.047). Endometrial volumes were independent of pregnancy development. Endometrial and subendometrial vascularization FIs were significantly higher in younger women. The subendometrial FI was significantly higher in patients who achieved pregnancy. Copyright © 2011 S. Karger AG, Basel.

  3. 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.

    Science.gov (United States)

    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

  4. Using Age-Based Life History Data to Investigate the Life Cycle and Vulnerability of Octopus cyanea

    Science.gov (United States)

    Herwig, Jade N.; Depczynski, Martial; Roberts, John D.; Semmens, Jayson M.; Gagliano, Monica; Heyward, Andrew J.

    2012-01-01

    Octopus cyanea is taken as an unregulated, recreationally fished species from the intertidal reefs of Ningaloo, Western Australia. Yet despite its exploitation and importance in many artisanal fisheries throughout the world, little is known about its life history, ecology and vulnerability. We used stylet increment analysis to age a wild O. cyanea population for the first time and gonad histology to examine their reproductive characteristics. O. cyanea conforms to many cephalopod life history generalisations having rapid, non-asymptotic growth, a short life-span and high levels of mortality. Males were found to mature at much younger ages and sizes than females with reproductive activity concentrated in the spring and summer months. The female dominated sex-ratios in association with female brooding behaviours also suggest that larger conspicuous females may be more prone to capture and suggests that this intertidal octopus population has the potential to be negatively impacted in an unregulated fishery. Size at age and maturity comparisons between our temperate bordering population and lower latitude Tanzanian and Hawaiian populations indicated stark differences in growth rates that correlate with water temperatures. The variability in life history traits between global populations suggests that management of O. cyanea populations should be tailored to each unique set of life history characteristics and that stylet increment analysis may provide the integrity needed to accurately assess this. PMID:22912898

  5. Using age-based life history data to investigate the life cycle and vulnerability of Octopus cyanea.

    Directory of Open Access Journals (Sweden)

    Jade N Herwig

    Full Text Available Octopus cyanea is taken as an unregulated, recreationally fished species from the intertidal reefs of Ningaloo, Western Australia. Yet despite its exploitation and importance in many artisanal fisheries throughout the world, little is known about its life history, ecology and vulnerability. We used stylet increment analysis to age a wild O. cyanea population for the first time and gonad histology to examine their reproductive characteristics. O. cyanea conforms to many cephalopod life history generalisations having rapid, non-asymptotic growth, a short life-span and high levels of mortality. Males were found to mature at much younger ages and sizes than females with reproductive activity concentrated in the spring and summer months. The female dominated sex-ratios in association with female brooding behaviours also suggest that larger conspicuous females may be more prone to capture and suggests that this intertidal octopus population has the potential to be negatively impacted in an unregulated fishery. Size at age and maturity comparisons between our temperate bordering population and lower latitude Tanzanian and Hawaiian populations indicated stark differences in growth rates that correlate with water temperatures. The variability in life history traits between global populations suggests that management of O. cyanea populations should be tailored to each unique set of life history characteristics and that stylet increment analysis may provide the integrity needed to accurately assess this.

  6. The need for a life-cycle based aging paradigm for nanomaterials: importance of real-world test systems to identify realistic particle transformations

    Science.gov (United States)

    Mitrano, Denise M.; Nowack, Bernd

    2017-02-01

    Assessing the risks of manufactured nanomaterials (MNM) has been almost exclusively focused on the pristine, as-produced materials with far fewer studies delving into more complex, real world scenarios. However, when considering a life-cycle perspective, it is clear that MNM released from commercial products during manufacturing, use and disposal are far more relevant both in terms of more realistic environmental fate and transport as well as environmental risk. The quantity in which the particles are released and their (altered) physical and chemical form should be identified and it is these metrics that should be used to assess the exposure and hazard the materials pose. The goal of this review is to (1) provide a rationale for using a life-cycle based approach when dealing with MNM transformations, (2) to elucidate the different chemical and physical forces which age and transform MNM and (3) assess the pros and cons of current analytical techniques as they pertain to the measurement of aged and transformed MNM in these complex release scenarios. Specifically, we will describe the possible transformations common MNM may undergo during the use or disposal of nano-products based on how these products will be used by the consumer by taking stock of the current nano-enabled products on the market. Understanding the impact of these transformations may help forecast the benefits and/or risks associated with the use of products containing MNM.

  7. Age

    Science.gov (United States)

    ... distressing side effects. Do anesthesia risks increase in older adults? One concern for older patients is that the aging brain is more ... related surgery risks that are more common in older people: ... problems with memory and paying attention. It may not start until a few days ...

  8. Carbon cycle instability as a cause of the late Pleistocene ice age oscillations - Modeling the asymmetric response

    Science.gov (United States)

    Saltzman, Barry; Maasch, Kirk A.

    1988-01-01

    A dynamical model of the Pleistocene ice ages is presented, which incorporates many of the qualitative ideas advanced recently regarding the possible role of ocean circulation, chemistry, temperature, and productivity in regulating long-term atmospheric carbon dioxide variations. This model involves one additional term (and free parameter) beyond that included in a previous model (Saltzman and Sutera, 1987), providing the capacity for an asymmetric response. It is shown that many of the main features exhibited by the delta(O-18)-derived ice record and the Vostok core/delta(C-13)-derived carbon dioxide record in the late Pleistocene can be deduced as a free oscillatory solution of the model.

  9. Cycling in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Alexis Zander

    2013-01-01

    Full Text Available Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants’ confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

  10. Constitutive Expression of Inducible Cyclic Adenosine Monophosphate Early Repressor (ICER) in Cycling Quiescent Hematopoietic Cells: Implications for Aging Hematopoietic Stem Cells.

    Science.gov (United States)

    Greco, Steven J; Yehia, Ghassan; Potian, Julius A; Molina, Carlos A; Rameshwar, Pranela

    2017-02-01

    Despite extensive insights on the interaction between hematopoietic stem cells (HSCs) and the supporting bone marrow (BM) stroma in hematopoietic homeostasis there remains unanswered questions on HSC regulation. We report on the mechanism by which HSCs attain cycling quiescence by addressing a role for inducible cyclic AMP early repressor (ICER). ICER negatively transcriptional regulators of cAMP activators such as CREM and CREB. These activators can be induced by hematopoietic stimulators such as cytokines. We isolated subsets of hematopoietic cells from ten healthy donors: CD34(+)CD38(-)/c-kit (+) (primitive progenitor), CD34(+)CD38(+)/c-kit(low) (mature progenitor) and CD34(-)CD38(+/-)/c-kit(low/-) (differentiated lineage-). The relative maturity of the progenitors were verified in long-term culture initiating assay. Immunoprecipitation indicated the highest level of ICER in the nuclear extracts of CD34(+)/CD38(-) cells. Phospho (p)-CREM was also present suggesting a balance between ICER and p-CREM in HSC. ICER seems to be responsible for decrease in G1 transition, based on reduced Cdk4 protein, decreased proliferation and functional studies with propidium iodide. There were no marked changes in the cycling inhibitors, p15 and p-Rb, suggesting that ICER may act independently of other cycling inhibitors. The major effects of ICER were validated with BM mononuclear cells (BMNCs) in which ICER was ectopically expressed, and with BMNCs resistant to 5-fluorouracil- or cyclophosphamide. In total, this study ascribes a novel role for ICER in G1 checkpoint regulation in HSCs. These findings are relevant to gene therapy that require engineering of HSCs, age-related disorders that are associated with hematopoietic dysfunction and other hematological disorders.

  11. Mitochondrial biogenesis drives a vicious cycle of metabolic insufficiency and mitochondrial DNA deletion mutation accumulation in aged rat skeletal muscle fibers.

    Directory of Open Access Journals (Sweden)

    Allen Herbst

    Full Text Available Aged muscles possess dysfunctional fibers that contain intracellular expansions of somatically derived mitochondrial DNA deletion mutations. At high abundance, these mutations disrupt the expression of mitochondrially-encoded protein subunits of the electron transport chain resulting in aerobic respiration deficient muscle fiber segments. These fiber segments atrophy and break contributing to the loss of muscle mass and function that occurs with age. By combining micro-dissection of individual muscle fibers with microarray analysis, we observed the response induced within these abnormal muscle fibers and detected an increase in many genes affecting metabolism and metabolic regulation. The transcriptional profile and subsequent protein validation suggested that a non-compensatory program of mitochondrial biogenesis was initiated. We hypothesized that this non-adaptive program of mitochondrial biogenesis was driving mtDNA deletion mutation accumulation. We tested this hypothesis by treating aged rats with β-Guanidinopropionic acid, a compound that stimulates mitochondrial biogenesis. β-Guanidinopropionic acid treatment increased muscle mitochondrial genome copy number and resulted in a 3.7 fold increase in the abundance of electron transport chain negative muscle fiber segments. We conclude that in electron transport system abnormal muscle fiber segments, a vicious cycle of metabolic insufficiency and non-compensatory mitochondrial biogenesis drive mtDNA deletion mutation accumulation.

  12. A STUDY OF SYMPATHETIC FUNCTION TESTS DURING NORMAL MENSTRUAL CYCLE IN YOUNG FEMALES IN THE AGE GROUP OF 18-25 YEARS

    Directory of Open Access Journals (Sweden)

    Aparajita Chakraborty

    2016-08-01

    Full Text Available BACKGROUND The menstrual cycle is not only a monthly cycle involving endometrial and cervical changes, but also is associated with many physical, psychological and behavioural changes. AIMS The study we have undertaken here was conducted to assess the blood pressure changes in response to isometric hand grip exercise test, cold pressor test and postural challenge test during the three different phases of the menstrual cycle in normal healthy females. SETTINGS AND DESIGN The present study was a cross-sectional study involving a study group of thirty healthy females. The tests were done in Department of Physiology, Silchar Medical College & Hospital. METHODS AND MATERIALS We randomly selected thirty healthy young girls in the age group of 18-25 years for our study. The resting blood pressure was recorded and the cardiovascular sympathetic function tests performed were Isometric handgrip exercise test, cold pressor test and postural challenge test. STATISTICAL ANALYSIS USED Statistical analysis was obtained by using ANOVA and paired-t test techniques. SPSS 18.0 and MS Excel software were used to perform the analysis. RESULTS Secretory (luteal phase presented with a significant increase in the resting systolic blood pressure (119.1±4.41 and diastolic blood pressure (74.43±4.26, as compared to menstrual phase (SBP 116.11±4.23 & DBP 72.13±3.44 and proliferative (Follicular phase (SBP 110.23±4.46 & DBP 69.13±3.13. This shows a sympathetic hyperactivity in luteal phase (p<0.05. The systolic and diastolic blood pressure also showed significant increase (p<0.05 in response to three tests. 1. Isometric handgrip exercise, 2. Cold pressor tests and 3. Postural challenge test, during their luteal phase as compared to the other two phases of menstrual cycle. CONCLUSION Our study shows that sympathetic activity is highest during luteal phase and lowest in the follicular phase as compared to the menstrual phase.

  13. Assimilating the ICE-6G_C Reconstruction of the Latest Quaternary Ice Age Cycle Into Numerical Simulations of the Laurentide and Fennoscandian Ice Sheets

    Science.gov (United States)

    Stuhne, G. R.; Peltier, W. R.

    2017-12-01

    We analyze the effects of nudging 100 kyr numerical simulations of the Laurentide and Fennoscandian ice sheets toward the glacial isostatic adjustment-based (GIA-based) ICE-6G_C reconstruction of the most recent ice age cycle. Starting with the ice physics approximations of the PISM ice sheet model and the SeaRISE simulation protocols, we incorporate nudging at characteristic time scales, τf, through anomalous mass balance terms in the ice mass conservation equation. As should be expected, these mass balances exhibit physically unrealistic details arising from pure GIA-based reconstruction geometry when nudging is very strong (τf=20 years for North America), while weakly nudged (τf=1,000 years) solutions deviate from ICE-6G_C sufficiently to degrade its observational fit quality. For reasonable intermediate time scales (τf=100 years and 200 years), we perturbatively analyze nudged ice dynamics as a superposition of "leading-order smoothing" that diffuses ICE-6G_C in a physically and observationally consistent manner and "higher-order" deviations arising, for instance, from biases in the time dependence of surface climate boundary conditions. Based upon the relative deviations between respective nudged simulations in which these biases follow surface temperature from ice cores and eustatic sea level from marine sediment cores, we compute "ice core climate adjustments" that suggest how local paleoclimate observations may be applied to the systematic refinement of ICE-6G_C. Our results are consistent with a growing body of evidence suggesting that the geographical origins of Meltwater Pulse 1B (MWP1b) may lie primarily in North America as opposed to Antarctica (as reconstructed in ICE-6G_C).

  14. The influence of coping strategies and behavior on the physiological response to social stress in women: The role of age and menstrual cycle phase.

    Science.gov (United States)

    Villada, Carolina; Espin, Laura; Hidalgo, Vanesa; Rubagotti, Sara; Sgoifo, Andrea; Salvador, Alicia

    2017-03-01

    There is information indicating that the variations induced by the menstrual cycle may influence the capacity of young women to respond to stress. The physiological response to stress changes across the stages of the lifespan; however, in spite of the great increase in life expectancy, the way women react after menopause, a period characterized by a dramatic decline in sex hormones, has not been sufficiently studied. The main objective of the study was to examine the capacity to respond to and recover from an acute social stressor in post-menopausal women compared to young women. The second objective was to investigate the consequences of behavior on the self-regulatory systems. We measured behavior, cortisol, and heart rate during a speaking task in front of a committee in sixty-seven women: 36 post-menopausal and 31 pre-menopausal (follicular group n=14; luteal group n=17). No differences in heart rate reactivity between three groups were found. Post-menopausal women showed less cortisol reactivity to stress; they also displayed a higher percentage of Gestures during the speaking task, reflecting a clearer pattern of active coping compared to the young women. In post-menopausal women, behaviors that reflect active coping strategies were related to better autonomic regulation. By contrast, in pre-menopausal women, cortisol changes seemed to be modulated by passive and reactive behaviors such as Submission and Assertion. These results emphasize the importance of considering age and Hormonal Status in coping processes, including reactivity and recovery from stressful situations. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Evaluation of color and radon exhalation rate in granite rocks between accelerated aging cycles; Avaliacao da cor e taxa de exalacao de radonio em rochas graniticas entre ciclos de envelhecimento acelerado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Francisco Diones Oliveira

    2016-07-01

    Data used for the assessment of the analyzes performed on three types of dimension stone (Juparana Bordeaux, Branco Nevasca and Golden Artico), in natural state and after several cycles of accelerated aging are presented, correlating them with the gas exhalation rate radon issued by the analyzed lithologies. In the samples were conducted permeability, porosity, colorimetry, image analysis, petrographic and exhalation rate of radon, accompanied by aging tests on climate simulation chamber which simulates change situations of materials by weathering agents, accelerating wear and tear samples. The measurements were performed on samples in natural state, with 50 and 100 cycles of aging acceleration, where each cycle corresponds to variations in temperature and humidity in climatic simulation chamber, with the addition of an internal atmosphere of SO{sub 2} with 25 concentration ppm. The results obtained during the tests were related to better analysis of the changes observed on the samples and the variation rate of exhalation radon emitted. The rocks have radon concentration values above the limits suggested by relevant international agencies (200-400 Bq/m³), with average values in the natural state, in 6149, 1619 and 866 Bq/m³ for Juparana Bordeaux, Branco Nevasca and Golden Arctic, respectively. The other aging cycles (50 and 100 cycles) showed an average increase of 0.8% for Juparana Bordeaux, 6.9% for White Blizzard and -23.87% for the Golden Arctic, with 50 cycles. From 50 to 100 cycles, there was reduction of 3.43% for Juparana Bordeaux and 22.15% for Branco Nevasca and an increase of 13.82% in the Golden Artico. The porosity results in the natural state obtained values an average of 0.696% for Juparana Bordeaux, 0.919% for Branco Nevasca and 0.830% for Golden Artico, and after 50 cycles of accelerated aging, obtained 0.621% to Juparana Bordeaux, 0.910% for Branco Nevasca and 0.840% for Golden Artico. The permeability of the samples showed values in the natural

  16. 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)

  17. Biogeochemical Cycling

    Science.gov (United States)

    Bebout, Brad; Fonda, Mark (Technical Monitor)

    2002-01-01

    This lecture will introduce the concept of biogeochemical cycling. The roles of microbes in the cycling of nutrients, production and consumption of trace gases, and mineralization will be briefly introduced.

  18. Experimental investigation of air relative humidity (RH) cycling tests on MEA/cell aging in PEMFC. Pt. II. Study of low RH cycling test with air RH at 62%/0%

    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, Nancy University, Vandoeuvre-les-Nancy (France)

    2012-06-15

    The effect of low relative humidity (RH) cycling (RH{sub C} 62%/0%) on the degradation mechanisms of a single proton exchange membrane fuel cell (5 x 5 cm{sup 2}) was investigated and compared to a cell operated at constant humidification (RH{sub C} = 62%). The overall cell performance loss was near 33 {mu}V h{sup -1}, which is greater than the voltage decay under constant RH condition near 3 {mu}V h{sup -1}. The electroactive surface was reduced but to an acceptable level. Impedance spectroscopy revealed that the ohmic and charge transfer resistances were reduced by the likely improved hydration of the ionomeric layer at the catalyst due to hydrogen crossover. This was so important that H{sub 2} starvation was finally responsible for the collapse of the cell after 650 h. Transmission electron microscopy showed occurrence of various phenomena, e.g., bubbles and pinholes formation in the membrane due to local overheat from hydrogen combustion at the cathode, and thickness reduction of catalytic layers. The water up take obtained by {sup 1}H NMR within the membrane electrode assembly (MEA) after low RH cycling reduced by 24% compared to a fresh MEA. Observations are also compared to those obtained at high RH cycling (RH{sub C} 62%/100%) presented in Part I of this study [1]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Repetition and severity of suicide attempts across the life cycle: a comparison by age group between suicide victims and controls with severe depression

    OpenAIRE

    Berglund Mats; Brådvik Louise

    2009-01-01

    Abstract Background Suicide attempts have been shown to be less common in older age groups, with repeated attempts generally being more common in younger age groups and severe attempts in older age groups. Consistently, most studies have shown an increased suicide risk after attempts in older age. However, little is known about the predictive value of age on repeated and severe suicide attempts for accomplished suicide. The aim of the present study was to investigate the reduced incidence for...

  20. Effects of Thermal Cycling and Thermal Aging on the Hermeticity and Strength of Silver-Copper Oxide Air-Brazed Seals

    Energy Technology Data Exchange (ETDEWEB)

    Weil, K. Scott; Coyle, Christopher A.; Darsell, Jens T.; Xia, Gordon; Hardy, John S.

    2005-12-01

    Thermal cycle and exposure tests were conducted on ceramic-to-metal joints prepared by a new sealing technique. Known as reactive air brazing, this joining method is currently being considered for use in sealing various high-temperature solid-state electrochemical devices, including planar solid oxide fuel cells (pSOFC). In order to simulate a typical pSOFC application, test specimens were prepared by joining ceramic anode/electrolyte bilayers to washers, of the same composition as the common frame materials employed in pSOFC stacks, using a filler metal composed of 4mol% CuO in silver. The brazed samples were exposure tested at 750°C for 200, 400, and 800hrs in both simulated fuel and air environments and thermally cycled at rapid rate (75°C/min) between room temperature and 750°C for as many as fifty cycles. Subsequent joint strength testing and microstructural analysis indicated that the samples exposure tested in air displayed little degradation with respect to strength, hermeticity, or microstructure out to 800hrs of exposure. Those tested in fuel showed no change in rupture strength or loss in hermeticity after 800hrs of high-temperature exposure, but did undergo microstructural change due to the dissolution of hydrogen into the silver-based braze material. Air brazed specimens subjected to rapid thermal cycling exhibited no loss in joint strength or hermeticity, but displayed initial signs of seal delamination along the braze/electrolyte interface after 50 cycles.

  1. The Efficacy of a Pre-Workout Vegan Supplement on High-Intensity Cycling Performance in Healthy College-Aged Males.

    Science.gov (United States)

    Gallien, Gabrielle; Bellar, David; Davis, Greggory R

    2017-11-02

    There is a limited supply of sport nutrition supplements currently available for vegan or vegetarian athletes. In addition, the efficacy of a vegan or vegetarian pre-workout supplement that does not contain any processed ingredients or stimulants is currently unknown. The purpose of the current study was to examine the effects of an unprocessed vegan pre-workout supplement on high-intensity cycling performance. Participants completed three separate cycling trials following the consumption of a vegan pre-workout supplement, an isocaloric processed supplement, or a zero-calorie placebo supplement. Each supplement was consumed 30 minutes prior to each trial, and each cycling trial was separated by a minimum of 72 hours. Supplements were administered using a randomized, double-blind cross-over design. Each cycling trial was performed at a workload equal to 80% VO 2peak until exhaustion. The average time in seconds (s) until exhaustion values for the vegan, isocaloric, and zero-calorie supplements were 482 ± 163, 480 ± 157, and 496 ± 238, respectively. Consumption of the vegan supplement did not significantly improve performance compared to an isocaloric and zero-calorie supplement (F = 0.12, p =.89). The results of this study indicate that individuals who choose a vegan pre-workout supplement (over an isocaloric or zero-calorie product) will not experience any acute decrements or ergogenic benefits in cycling performance. Although the present study does not support performance benefits of the tested vegan pre-workout supplement before cycling, additional research examining various exercise intensities and modalities is warranted.

  2. Effects of thermal cycling and thermal aging on the hermeticity and strength of silver-copper oxide air-brazed seals

    Energy Technology Data Exchange (ETDEWEB)

    Scott Weil, K.; Coyle, Christopher A.; Hardy, John S. [Energy Science and Technology Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Darsell, Jens T. [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States); Xia, Gordon G. [Environmental Technology Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2005-12-01

    Thermal cycle and exposure tests were conducted on ceramic-to-metal joints prepared by a new sealing technique. Known as reactive air brazing, this joining method is currently being considered for use in sealing various high-temperature solid-state electrochemical devices, including planar solid oxide fuel cells (pSOFC). In order to simulate a typical pSOFC application, test specimens were prepared by joining ceramic anode/electrolyte bilayers to metal washers, of the same composition as the common frame materials employed in pSOFC stacks, using a filler metal composed of 4mol% CuO in silver. The brazed samples were exposure tested at 750{sup o}C for 200, 400, and 800h in both simulated fuel and air environments and thermally cycled at rapid rate (75{sup o}Cmin{sup -1}) between room temperature and 750{sup o}C for as many as 50 cycles. Subsequent joint strength testing and microstructural analysis indicated that the samples exposure tested in air displayed little degradation with respect to strength, hermeticity, or microstructure out to 800h of exposure. Those tested in fuel showed no change in rupture strength or loss in hermeticity after 800h of high-temperature exposure, but did undergo microstructural change due to the dissolution of hydrogen into the silver-based braze material. Air-brazed specimens subjected to rapid thermal cycling exhibited no loss in joint strength or hermeticity, but displayed initial signs of seal delamination along the braze-electrolyte interface after 50 cycles. (author)

  3. Assessing Cycling Participation in Australia

    Directory of Open Access Journals (Sweden)

    Chris Rissel

    2013-01-01

    Full Text Available Planning and evaluating cycling programs at a national or state level requires accurate measures of cycling participation. However, recent reports of cycling participation have produced very different estimates. This paper examines the reported rates of cycling in five recent population surveys of cycling. Three surveys (one national and two from Sydney asking respondents when they last rode a bicycle generated cycling participation (cycled in the past year estimates of 29.7%, 34.1% and 28.9%. Two other national surveys which asked participants to recall (unprompted any physical activity done for exercise, recreation or sport in the previous 12 months, estimated cycling in the past year as 11.1% and 6.5%. While unprompted recall of cycling as a type of physical activity generates lower estimates of cycling participation than specific recall questions, both assessment approaches produced similar patterns of cycling by age and sex with both approaches indicating fewer women and older adults cycling. The different question styles most likely explain the substantial discrepancies between the estimates of cycling participation. Some differences are to be expected due to sampling variability, question differences, and regional variation in cycling.

  4. Middle-aged Subjects With Habitual Low-speed Cycling Exercise Have Greater Mononuclear Cell Responsiveness Against Human Hepatitis B Virus Surface Antigen

    Directory of Open Access Journals (Sweden)

    Kuen-Chang Hsieh

    2010-06-01

    Conclusion: The results reveal that the immune response of MNC, which are stimulated by PHA to suppress hepatitis B surface antigen expression, is greater in middle-aged subjects with low-speed HCE than in sedentary subjects.

  5. Assessment of Accrued Damage and Remaining Useful Life in Leadfree Electronics Subjected to Multiple Thermal Environments of Thermal Aging and Thermal Cycling

    Data.gov (United States)

    National Aeronautics and Space Administration — A method has been developed for prognostication of accrued prior damage in electronics subjected to overlapping sequential environments of thermal aging and thermal...

  6. Assessment of the Potential Role of Tryptophan as the Precursor of Serotonin and Melatonin for the Aged Sleep-wake Cycle and Immune Function: Streptopelia Risoria as a Model

    Directory of Open Access Journals (Sweden)

    Sergio D. Paredes

    2009-01-01

    Full Text Available In the present review we summarize the relationship between the amino acid, tryptophan, the neurotransmitter, serotonin, and the indole, melatonin, with the rhythms of sleep/wake and the immune response along with the possible connections between the alterations in these rhythms due to aging and the so-called “serotonin and melatonin deficiency state.” The decrease associated with aging of the brain and circulating levels of serotonin and melatonin seemingly contributes to the alterations of both the sleep/wake cycle and the immune response that typically accompany old age. The supplemental administration of tryptophan, e.g. the inclusion of tryptophan-enriched food in the diet, might help to remediate these age- related alterations due to its capacity of raise the serotonin and melatonin levels in the brain and blood. Herein, we also summarize a set of studies related to the potential role that tryptophan, and its derived product melatonin, may play in the restoration of the aged circadian rhythms of sleep/wake and immune response, taking the ringdove (Streptopelia risoria as a suitable model.

  7. Ageing Mechanisms and Control. Specialists’ Meeting on Life Management Techniques for Ageing Air Vehicles (Les mecanismes vieillissants et le controle) (Reunions des specialistes des techniques de gestion du cycle de vie pour vehicules aeriens vieillissants)

    Science.gov (United States)

    2003-02-01

    SUR-SEINE CEDEX, FRANCE RTO MEETING PROCEEDINGS 79(II) Ageing Mechanisms and Control (Les mécanismes vieillissants et le contrôle) Specialists...aériens vieillissants ) Papers presented at the RTO Applied Vehicle Technology Panel (AVT) Specialists’ Meeting held in Manchester, United Kingdom, 8-11...RUE ANCELLE, F-92201 NEUILLY-SUR-SEINE CEDEX, FRANCE RTO MEETING PROCEEDINGS 79(II) Ageing Mechanisms and Control (Les mécanismes vieillissants et le

  8. Female age, serum antimüllerian hormone level, and number of oocytes affect the rate and number of euploid blastocysts in in vitro fertilization/intracytoplasmic sperm injection cycles.

    Science.gov (United States)

    La Marca, Antonio; Minasi, Maria Giulia; Sighinolfi, Giovanna; Greco, Pierfrancesco; Argento, Cindy; Grisendi, Valentina; Fiorentino, Francesco; Greco, Ermanno

    2017-11-01

    To study the relative role of female age and ovarian reserve, measured through serum antimüllerian hormone (AMH) in determining the rate and number of euploid blastocysts in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles. Retrospective analysis of cycles performed in 2014-2015. Tertiary referral IVF center. A total of 578 infertile couples undergoing IVF/ICSI and preimplantation genetic screening (PGS) analysis. All embryos were cultured and biopsied at the blastocyst stage. The method involved whole-genome amplification followed by array comparative genome hybridization. Serum AMH was measured by means of the modified Beckman Coulter AMH Gen II assay. The rate and number of euploid blastocysts and their correlation with ovarian reserve and response to stimulation. The mean (±SD) age of patients was 37.6 ± 4.1 years, and the mean number of blastocysts per patient was 3.1 ± 2. The total number of blastocysts available to the analysis was 1,814, and 36% of them were euploid after PGS. Age and serum AMH were significantly and independently related to the rate of euploid blastocysts available for patients. As an effect of the cohort size, the number of mature oocytes positively affected the total number of euploid blastocysts per patient. A strong positive age-independent relationship between AMH level and the rate of euploid blastocysts was found. This confirms that the measurement of ovarian reserve by means of AMH has high relevance when counseling infertile patients. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  9. Glacial cycles

    DEFF Research Database (Denmark)

    Kaufmann, R. K.; Juselius, Katarina

    and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed......We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...

  10. Allergy immunotherapy across the life cycle to promote active and healthy ageing: from research to policies: An AIRWAYS Integrated Care Pathways (ICPs) programme item (Action Plan B3 of the European Innovation Partnership on active and healthy ageing) and the Global Alliance against Chronic Respiratory Diseases (GARD), a World Health Organization GARD research demonstration project.

    Science.gov (United States)

    Calderon, M A; Demoly, P; Casale, T; Akdis, C A; Bachert, C; Bewick, M; Bilò, B M; Bohle, B; Bonini, S; Bush, A; Caimmi, D P; Canonica, G W; Cardona, V; Chiriac, A M; Cox, L; Custovic, A; De Blay, F; Devillier, P; Didier, A; Di Lorenzo, G; Du Toit, G; Durham, S R; Eng, P; Fiocchi, A; Fox, A T; van Wijk, R Gerth; Gomez, R M; Haathela, T; Halken, S; Hellings, P W; Jacobsen, L; Just, J; Tanno, L K; Kleine-Tebbe, J; Klimek, L; Knol, E F; Kuna, P; Larenas-Linnemann, D E; Linneberg, A; Matricardi, M; Malling, H J; Moesges, R; Mullol, J; Muraro, A; Papadopoulos, N; Passalacqua, G; Pastorello, E; Pfaar, O; Price, D; Del Rio, P Rodriguez; Ruëff, R; Samolinski, B; Scadding, G K; Senti, G; Shamji, M H; Sheikh, A; Sisul, J C; Sole, D; Sturm, G J; Tabar, A; Van Ree, R; Ventura, M T; Vidal, C; Varga, E M; Worm, M; Zuberbier, T; Bousquet, J

    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 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 the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing.

  11. Observations on the reproductive cycle, age and growth of the salema, Sarpa salpa (Osteichthyes: Sparidae along the western central coast of Italy

    Directory of Open Access Journals (Sweden)

    Alessandro Criscoli

    2006-03-01

    Full Text Available The sexual maturation and the growth of the salema, Sarpa salpa (Linnaeus, 1758, along the Italian Mediterranean coast (central Italy, were studied in fish (n = 105 killed incidentally by underwater explosions during the construction of Civitavecchia harbour in 1999 and specimens collected with trammel nets (n = 339. This species is characterized by a protandric hermaphroditism and the sex change process occurs between 24 and 31 cm TL corresponding to a wide range of ages (3-7 years. Size at maturity (L50 was 19.5 cm, at which almost all the individuals were males. Two distinct spawning periods were observed: one in spring, from March to May, and the other in autumn, from the end of September to November. During the first year, compensatory growth occurred in the individuals born in the two periods. An annual regular pattern of ring deposition was identified in the otoliths: the translucent ring was laid down during the winter months, while the opaque ring was formed during the summer months. Back-calculated lengths at age were used to estimate the parameters of the Von Bertalanffy growth equation which were: L∞ = 37.27 cm, K = 0.27 year-1 and t0 = -0.53 year. Salema showed isometric growth (b = 3.04; P = 0.84; t = 0.19.

  12. CYCLE CONTROL

    African Journals Online (AJOL)

    changed to gestodene. Although large- scale comparative trials are needed to confirm this finding, evidence suggests that cycle control with gestodene is better than for monophasic preparations containing desogestrel, norgestimate or levonorgestrel,10 as well as for levonorg- estrel-or norethisterone-containing triphasics.

  13. Menu Cycles.

    Science.gov (United States)

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  14. Simple cycles

    OpenAIRE

    Rivin, Igor

    1999-01-01

    We obtain sharp bounds for the number of n-cycles in a finite graph as a function of the number of edges, and prove that the complete graph is optimal in more ways than could be imagined. En route, we prove some sharp estimates on power sums.

  15. Happy Cycling

    DEFF Research Database (Denmark)

    Geert Jensen, Birgitte; Nielsen, Tom

    2013-01-01

    og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...

  16. Understanding the carbon cycle in a Late Quaternary-age limestone aquifer system using radiocarbon of dissolved inorganic and organic carbon

    Science.gov (United States)

    Bryan, Eliza; Meredith, Karina T.; Baker, Andy; Andersen, Martin S.; Post, Vincent E. A.

    2017-04-01

    Estimating groundwater residence time is critical for our understanding of hydrogeological systems, for groundwater resource assessments and for the sustainable management of groundwater resources. Due to its capacity to date groundwater up to 30 thousand years old, as well as the ubiquitous nature of dissolved carbon (as organic and inorganic forms) in groundwater, 14C is the most widely used radiogenic dating technique in regional aquifers. However, the geochemistry of carbon in groundwater systems includes interaction with the atmosphere, biosphere and geosphere, which results in multiple sources and sinks of carbon that vary in time and space. Identifying these sources of carbon and processes relating to its release or removal is important for understanding the evolution of the groundwater and essential for residence time calculations. This study investigates both the inorganic and organic facets of the carbon cycle in groundwaters throughout a freshwater lens and mixing zone of a carbonate island aquifer and identifies the sources of carbon that contribute to the groundwater system. Groundwater samples were collected from shallow (5-20 m) groundwater wells on a small carbonate Island in Western Australia in September 2014 and analysed for major and minor ions, stable water isotopes (SWIs: δ18O, δ2H), 3H, 14C and 13C carbon isotope values of both DIC and DOC, and 3H. The composition of groundwater DOC was investigated by Liquid Chromatography-Organic Carbon Detection (LC-OCD) analysis. The presence of 3H (0.12 to 1.35 TU) in most samples indicates that groundwaters on the Island are modern, however the measured 14CDIC values (8.4 to 97.2 pmc) suggest that most samples are significantly older due to carbonate dissolution and recrystallisation reactions that are identified and quantified in this work. 14CDOC values (46.6 to 105.6 pMC) were higher than 14CDIC values and were well correlated with 3H values, however deeper groundwaters had lower 14CDOC values than

  17. The preventive effect of the bounding exercise programme on hamstring injuries in amateur soccer players: the design of a randomized controlled trial.

    Science.gov (United States)

    Van de Hoef, S; Huisstede, B M A; Brink, M S; de Vries, N; Goedhart, E A; Backx, F J G

    2017-08-22

    Hamstring injuries are the most common muscle injury in amateur and professional soccer. Most hamstring injuries occur in the late swing phase, when the hamstring undergoes a stretch-shortening cycle and the hamstring does a significant amount of eccentric work. The incidence of these injuries has not decreased despite there being effective injury prevention programmes focusing on improving eccentric hamstring strength. As this might be because of poor compliance, a more functional injury prevention exercise programme that focuses on the stretch-shortening cycle might facilitate compliance. In this study, a bounding exercise programme consisting of functional plyometric exercises is being evaluated. A cluster-randomized controlled trial (RCT). Male amateur soccer teams (players aged 18-45 years) have been randomly allocated to intervention and control groups. Both groups are continuing regular soccer training and the intervention group is additionally performing a 12-week bounding exercise programme (BEP), consisting of a gradual build up and maintenance programme for the entire soccer season. The primary outcome is hamstring injury incidence. Secondary outcome is compliance with the BEP during the soccer season and 3 months thereafter. Despite effective hamstring injury prevention programmes, the incidence of these injuries remains high in soccer. As poor compliance with these programmes may be an issue, a new plyometric exercise programme may encourage long-term compliance and is expected to enhance sprinting and jumping performance besides preventing hamstring injuries. NTR6129 . Retrospectively registered on 1 November 2016.

  18. Combined Effect of Hydrogen and Dynamic Strain Aging on Low Cycle Fatigue Behaviors of SA508 Gr.1a Low Alloy Steels in 310 .deg. C Deoxygenated Water

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hun; Kim, Jeong Hyeon; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of); Kim, Tae Soon [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2011-05-15

    Significant reduction of fatigue life of structural materials in nuclear power plants is one of the issues of considerable significance to maintain superior integrity throughout their service life. From extensive studies, hydrogen induced cracking (HIC) is widely accepted mechanisms for reduction of fatigue life of low alloy steels (LAS) used as structural materials. Some of authors reported that hydrogen content in reactor pressure vessel could reach 2 {approx} 5 ppm during reactor operation. Hydrogen was resulted from corrosion reaction at the metal surface or crack tip in water. In addition, it has been reported that LAS is susceptible material for dynamic strain aging (DSA) in PWR environment at specific strain rate. Therefore, it is possible that the synergism between DSA and hydrogen might induce more significant LCF damage in PWR environment. In this regard, combined effect of DSA and hydrogen was investigated in this study. For that, LCF tests of SA508 Gr.1a LAS in various environments and tensile tests of hydrogen charged (H charged) samples in DSA range were conducted

  19. Menstrual Cycle

    Science.gov (United States)

    ... Effects of Aging on the Female Reproductive System Menstruation is the shedding of the lining of the ... throughout a woman's reproductive life, except during pregnancy. Menstruation starts during puberty (at menarche) and stops permanently ...

  20. Aging According to Biography.

    Science.gov (United States)

    Weiland, Steven

    1989-01-01

    Uses Erik Erikson's work to discuss how biographies treat aging. Explores how developmental theorists observe biographical representations of the life cycle and its applicability to aging. (Author/BHK)

  1. Safe cycling!

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    The HSE Unit will be running a cycling safety campaign at the entrances to CERN's restaurants on 14, 15 and 16 May. Pop along to see if they can persuade you to get back in the saddle!   With summer on its way, you might feel like getting your bike out of winter storage. Well, the HSE Unit has come up with some original ideas to remind you of some of the most basic safety rules. This year, the prevention campaign will be focussing on three themes: "Cyclists and their equipment", "The bicycle on the road", and "Other road users". This is an opportunity to think about the condition of your bike as well as how you ride it. From 14 to 16 May, representatives of the Swiss Office of Accident Prevention and the Touring Club Suisse will join members of the HSE Unit at the entrances to CERN's restaurants to give you advice on safe cycling (see box). They will also be organising three activity stands where you can test your knowle...

  2. Cycling infrastructure for reducing cycling injuries in cyclists.

    Science.gov (United States)

    Mulvaney, Caroline A; Smith, Sherie; Watson, Michael C; Parkin, John; Coupland, Carol; Miller, Philip; Kendrick, Denise; McClintock, Hugh

    2015-12-10

    Cycling is an attractive form of transport. It is beneficial to the individual as a form of physical activity that may fit more readily into an individual's daily routine, such as for cycling to work and to the shops, than other physical activities such as visiting a gym. Cycling is also beneficial to the wider community and the environment as a result of fewer motorised journeys. Cyclists are seen as vulnerable road users who are frequently in close proximity to larger and faster motorised vehicles. Cycling infrastructure aims to make cycling both more convenient and safer for cyclists. This review is needed to guide transport planning. To:1. evaluate the effects of different types of cycling infrastructure on reducing cycling injuries in cyclists, by type of infrastructure;2. evaluate the effects of cycling infrastructure on reducing the severity of cycling injuries in cyclists;3. evaluate the effects of cycling infrastructure on reducing cycling injuries in cyclists with respect to age, sex and social group. We ran the most recent search on 2nd March 2015. We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (OvidSP), Embase Classic + Embase(OvidSP), PubMed and 10 other databases. We searched websites, handsearched conference proceedings, screened reference lists of included studies and previously published reviews and contacted relevant organisations. We included randomised controlled trials, cluster randomised controlled trials, controlled before-after studies, and interrupted time series studies which evaluated the effect of cycling infrastructure (such as cycle lanes, tracks or paths, speed management, roundabout design) on cyclist injury or collision rates. Studies had to include a comparator, that is, either no infrastructure or a different type of infrastructure. We excluded studies that assessed collisions that occurred as a result of competitive cycling. Two review authors examined the titles and

  3. Psychosocial Consequences of Weight Cycling.

    Science.gov (United States)

    Bartlett, Susan J.; And Others

    1996-01-01

    Participants were 130 obese women who reported undertaking a mean lifetime total of 4.7 major diets on which they had lost a mean of 45.9 kilograms. Participants with a severe history of weight cycling had a significantly younger age of onset of obesity than mild cyclers and reported initiating dieting at a significantly younger age and lower…

  4. Hydrological cycle.

    Science.gov (United States)

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.

  5. Clinical application of a nomogram based on age, serum FSH and AMH to select the FSH starting dose in IVF/ICSI cycles: a retrospective two-centres study.

    Science.gov (United States)

    Papaleo, Enrico; Zaffagnini, Stefano; Munaretto, Maria; Vanni, Valeria Stella; Rebonato, Giorgia; Grisendi, Valentina; Di Paola, Rossana; La Marca, Antonio

    2016-12-01

    To externally validate a nomogram based on ovarian reserve markers as a tool to optimize the FSH starting dose in IVF/ICSI cycles. A two-centres retrospective study including 398 infertile women undergoing their first IVF/ICSI cycle (June 2013-June 2014). IVF data were retrieved from two independent IVF centres in Italy (San Raffaele Hospital, Centre 1; Verona Hospital, Centre 2). A central lab for the routine measurement of AMH and FSH was used for both centres. All women were treated based on physical and hormonal characteristics according to locally adopted protocols. The nomogram was then retrospectively applied to the patients comparing the calculated starting dose to the one actually given. In Centre 1, 64/131 women (48.8%) had an ovarian response below the target. While 45 of these patients were treated with a maximal FSH starting dose (≥225 IU), n=19/131 (14.5%) were treated with a submaximal dose. The vast majority of them (n=17/19) would have received a higher FSH starting dose by using the nomogram. Seventeen patients (n=17/131) had hyper response and about half of them would have been treated with a reduced FSH starting dose according to the nomogram. In Centre 2, 142/267 patients (53.2%) had an ovarian response below the target. While 136 of these were treated with a maximal FSH starting dose (≥225 IU), n=6/267 were treated with a submaximal dose. The majority of them (n=5/6) would have received a higher FSH starting dose. Thirty-two (n=32/267) patients had hyper response and more than half of them would have been treated with a reduced FSH dose. In both Centres, applying the nomogram would have resulted in more appropriate FSH starting doses compared to the the ones actually given based on clinicians choices. The use of an objective algorithm based on patient's age, serum FSH and AMH levels may thus be an effective advice on the selection of the tailored FSH starting dose. Hence, the use of this easily available nomogram could increase the

  6. The timing and cause of glacial advances in the southern mid-latitudes during the last glacial cycle based on a synthesis of exposure ages from Patagonia and New Zealand

    Science.gov (United States)

    Darvill, Christopher M.; Bentley, Michael J.; Stokes, Chris R.; Shulmeister, James

    2016-10-01

    Glacier advances in the southern mid-latitudes during the last glacial cycle (ca. 110-10 ka) were controlled by changes in temperature and precipitation linked to several important ocean-climate systems. As such, the timing of glacial advance and retreat can yield important insights into the mechanisms of Southern Hemisphere climate change. This is particularly important given that several recent studies have demonstrated significant glacial advances prior to the global Last Glacial Maximum (gLGM) in Patagonia and New Zealand, the cause of which are uncertain. The recent increase in chronological studies in these regions offers the opportunity to compare regional trends in glacial activity. Here, we compile the first consistent 10Be exposure-dating chronologies for Patagonia and New Zealand to highlight the broad pattern of mid-latitude glacial activity over the last glacial cycle. Our results show that advances or still stands culminated at 26-27 ka, 18-19 ka and 13-14 ka in both Patagonia and New Zealand and were broadly synchronous, but with an offset between regions of up to 900 years that cannot be explained by age calculation or physically plausible erosion differences. Furthermore, there is evidence in both regions for glacial advances culminating from at least 45 ka, during the latter half of Marine Isotope Stage (MIS) 3. Glacial activity prior to the gLGM differed from the large Northern Hemisphere ice sheets, likely due to favourable Southern Hemisphere conditions during late MIS 3: summer insolation reached a minimum, seasonality was reduced, winter duration was increasing, and sea ice had expanded significantly, inducing stratification of the ocean and triggering northward migration of oceanic fronts and the Southern Westerly Winds. Glacial advances in Patagonia and New Zealand during the gLGM were probably primed by underlying orbital parameters. However, the precise timing is likely to have been intrinsically linked to migration of the coupled ocean

  7. Effect of the recovery duration of a repeated sprint exercise on the power output, jumping performance and lactate concentration in pre-pubescent soccer players

    Directory of Open Access Journals (Sweden)

    Nikolaidis Pantelis T.

    2016-05-01

    Full Text Available Study aim: The aim of the present study was to examine the effect of two different recovery durations (2 min versus 5 min on the physiological responses (power output, stretch-shortening cycle and lactate concentration to a 5×6 s repeated cycling sprint exercise protocol in pre-pubescent soccer players.

  8. Measuring risky adolescent cycling behaviour.

    Science.gov (United States)

    Feenstra, Hans; Ruiter, Robert A C; Schepers, Jan; Peters, Gjalt-Jorn; Kok, Gerjo

    2011-09-01

    Adolescents are at a greater risk of being involved in traffic accidents than most other age groups, even before they start driving cars. This article aims to determine the factor structure of a self-report questionnaire measuring adolescent risky cycling behaviour, the ACBQ (Adolescent Cycling Behaviour Questionnaire). The questionnaire's structure was based on the widely used Driver Behaviour Questionnaire (DBQ). A sample of secondary school students (N = 1749; age range: 13-18 years) filled out the questionnaire. Factor analysis revealed a three-factor structure underlying the questionnaire, which was confirmed on two equally large portions of the entire sample. These three underlying factors were identified as errors, common violations and exceptional violations. The ACBQ is a useful instrument for measuring adolescents' risky cycling behaviour.

  9. Optimal Life Cycle Portfolio Choice with Housing Market Cycles

    DEFF Research Database (Denmark)

    Fischer, Marcel; Stamos, Michael Z.

    2013-01-01

    In recent decades U.S. households have experienced residential house prices moving persistently, that is, returns being positively serially correlated. We set up a realistically calibrated life cycle model with slow-moving time variation in expected housing returns, showing that not only age, labor...... income, and pre-existing housing wealth but also the state of the housing market significantly affect household decisions. Consistently with the data, the model predicts that in good states of housing market cycles (1) homeownership rates increase, (2) households buying homes invest a larger share...

  10. Essays on economic cycles

    NARCIS (Netherlands)

    Groot, de E.A. (Bert)

    2006-01-01

    Schumpeter’s line of thought of multiple economic cycles is further investigated. The existence of multiple cycles in economic variables is demonstrated. In basic innovations five different cycles are found. Multiple cycle structures are shown in various macro-economic variables from the United

  11. Preliminary results from a field experiment on e-bike safety : speed choice and mental workload for middle-aged and elderly cyclists. Paper presented at the International Cycling Safety Conference 2013, Helmond, The Netherland, 20-21 November 2013.

    NARCIS (Netherlands)

    Twisk, D.A.M. Boele, M.J. Vlakveld, W.P. Christoph, M. Sikkema, R. Remij, R. & Schwab, A.L.

    2014-01-01

    To study the safety of e-bikes for the elderly, an experimental field study was conducted, using instrumented bicycles and comparing two age groups: older cyclists, n= 29, mean age = 70, SD = 4.2 and middle-aged cyclists, n = 29, mean age = 38, SD = 4.3. All were regular cyclists. They rode a fixed

  12. Solar Cycle 25: Another Moderate Cycle?

    Science.gov (United States)

    Cameron, R. H.; Jiang, J.; Schüssler, M.

    2016-06-01

    Surface flux transport simulations for the descending phase of Cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during the upcoming activity minimum together with a realistic uncertainty range. The expectation value for the dipole moment around 2020 (2.5 ± 1.1 G) is comparable to that observed at the end of Cycle 23 (about 2 G). The empirical correlation between the dipole moment during solar minimum and the strength of the subsequent cycle thus suggests that Cycle 25 will be of moderate amplitude, not much higher than that of the current cycle. However, the intrinsic uncertainty of such predictions resulting from the random scatter of the source properties is considerable and fundamentally limits the reliability with which such predictions can be made before activity minimum is reached.

  13. The preventive effect of the bounding exercise programme on hamstring injuries in amateur soccer players : The design of a randomized controlled trial

    NARCIS (Netherlands)

    Van de Hoef, S.; Huisstede, B. M. A.; Brink, M. S.; de Vries, N.; Goedhart, E. A.; Backx, F. J. G.

    2017-01-01

    Background: Hamstring injuries are the most common muscle injury in amateur and professional soccer. Most hamstring injuries occur in the late swing phase, when the hamstring undergoes a stretch-shortening cycle and the hamstring does a significant amount of eccentric work. The incidence of these

  14. Creative Cycling of News Professionals

    Directory of Open Access Journals (Sweden)

    Astrid Gynnild, PhD.

    2007-03-01

    Full Text Available The theory of creative cycling emerged from my PhD study of news professionals in Norway. The study was carried out according to classic grounded theory principles (Glaser and Strauss 1967, Glaser 1978, 1998, 2001, 2005, and the area of interest was the performance of news journalism in the multimedia age. The theory runs counter to widespread tendencies of industrial age thinking in news media. It emphasizes news professionals’ search for meaning in their daily work, and suggests that their main concern is self-fulfillment through original contribution. The dilemma and resolution, creative cycling, is a basic social process continuously going within inner and outer framings. It consists of three interrelated dimensions: productive processing, breaks and shifts and inspirational looping.

  15. Life cycle assessment (LCA)

    DEFF Research Database (Denmark)

    Thrane, Mikkel; Schmidt, Jannick Andresen

    2004-01-01

    The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards.......The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards....

  16. Menstrual Cycle Problems

    Science.gov (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Menstrual Cycle ProblemsFrom missed periods to painful periods, menstrual cycle problems are common, but usually not serious. Follow ...

  17. Monitoring city wide patterns of cycling safety.

    Science.gov (United States)

    Boss, Darren; Nelson, Trisalyn; Winters, Meghan

    2018-02-01

    Many cities are making significant financial investments in cycling infrastructure with the aim of making cycling safer for riders of all ages and abilities. Methods for evaluating cycling safety tend to summarize average change for a city or emphasize change on a single road segment. Few spatially explicit approaches are available to evaluate how patterns of safety change throughout a city due to cycling infrastructure investments or other changes. Our goal is to demonstrate a method for monitoring changes in the spatial-temporal distribution of cycling incidents across a city. Using cycling incident data provided by the Insurance Corporation of British Columbia, we first compare planar versus network constrained kernel density estimation for visualizing incident intensity across the street network of Vancouver, Canada. Second, we apply a change detection algorithm explicitly designed for detecting statistically significant change in kernel density estimates. The utility of network kernel density change detection is demonstrated through the comparison of cycling incident densities following the construction of two cycle tracks in the downtown core of Vancouver. The methods developed and demonstrated for this study provide city planners, transportation engineers and researchers a means of monitoring city-wide change in the intensity of cycling incidents following enhancements to cycling infrastructure or other significant changes to the transportation network. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Cycling To Awareness.

    Science.gov (United States)

    Kozak, Stan

    1999-01-01

    Encourages environmental and outdoor educators to promote bicycling. In the community and the curriculum, cycling connects environmental issues, health and fitness, law and citizenship, appropriate technology, and the joy of being outdoors. Describes the Ontario Cycling Association's cycling strategy and its four components: school cycling…

  19. Estrous cycle and gestational age-dependent expression of members of the interleukin-36 subfamily in a semi-allogeneic model of infected and non-infected murine pregnancy

    Directory of Open Access Journals (Sweden)

    José Martin Murrieta Coxca

    2016-09-01

    Full Text Available The IL-36 subfamily is a recently described group of cytokines with pro-inflammatory behavior, comprising three agonists (α, β and γ, its receptor (R and one antagonist (Ra. The expression and function of IL-36 subfamily members in the estrous cycle in healthy and infected pregnancy have not been described. We evaluated mRNA and protein expression of IL-36 family members during the estrous cycle, implantation, fetal development and post-labor periods in a model of allogenic pregnancy in mice. We also explored the ability of Listeria monocytogenes to modulate expression of IL-36 subfamily members during pregnancy. Expression of IL-36 subfamily members showed different expression during the estrous cycle and pregnancy, but was induced at estrous, 16.5 days post coitum (dpc, 18.5 dpc and labor. IL-36 subfamily members showed a characteristic distribution in the glandular epithelium, perimetrium, myometrium, and stratum vasculare. Infection with Listeria monocytogenes during pregnancy induced strong production of IL-36 subfamily members, an observation that correlated with an increasing prevalence of fetal loss. Conclusions: IL-36 agonists showed specific patterns of mRNA and protein expression that might suggest functional specialization or specific target cells. Infection with Listeria monocytogenes during pregnancy induced strong production of IL-36 subfamily members.

  20. Estrous Cycle and Gestational Age-Dependent Expression of Members of the Interleukin-36 Subfamily in a Semi-Allogeneic Model of Infected and Non-Infected Murine Pregnancy

    Science.gov (United States)

    Murrieta-Coxca, José Martin; Gómez-Chávez, Fernando; Baeza-Martínez, Damariz Adriana; Cancino-Diaz, Mario Eugenio; Cancino-Diaz, Juan Carlos; Pérez-Tapia, Sonia Mayra; Reyes-Maldonado, Elba; Rodríguez-Martínez, Sandra

    2016-01-01

    The IL-36 subfamily is a recently described group of cytokines with pro-inflammatory behavior, comprising three agonists (α, β, and γ), its receptor (R), and one antagonist (Ra). The expression and function of IL-36 subfamily members in the estrous cycle in healthy and infected pregnancy has not been described. We evaluated mRNA and protein expression of IL-36 family members during the estrous cycle, implantation, fetal development, and post-labor periods in a model of allogenic pregnancy in mice. We also explored the ability of Listeria monocytogenes to modulate the expression of IL-36 subfamily members during pregnancy. Expression of IL-36 subfamily members showed different expression during the estrous cycle and pregnancy but was induced at estrous, 16.5 days post coitum (dpc), 18.5 dpc, and labor. IL-36 subfamily members showed a characteristic distribution in the glandular epithelium, perimetrium, myometrium, and stratum vasculare. Infection with L. monocytogenes during pregnancy induced strong production of IL-36 subfamily members, an observation that correlated with an increasing prevalence of fetal loss. In conclusion, IL-36 agonists showed specific patterns of mRNA and protein expression that might suggest functional specialization or specific target cells. Infection with L. monocytogenes during pregnancy induced strong production of IL-36 subfamily members. PMID:27713746

  1. The Solar Cycle

    Directory of Open Access Journals (Sweden)

    David H. Hathaway

    2010-03-01

    Full Text Available The Solar Cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. We examine a number of other solar activity indicators including the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores that vary in association with the sunspots. We examine the characteristics of individual solar cycles including their maxima and minima, cycle periods and amplitudes, cycle shape, and the nature of active latitudes, hemispheres, and longitudes. We examine long-term variability including the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double peaked maxima. We conclude with an examination of prediction techniques for the solar cycle.

  2. Female aging

    Directory of Open Access Journals (Sweden)

    Isabel Cristina Esposito Sorpreso

    2015-12-01

    Full Text Available SUMMARY Female aging is a process that involves hypoestrogenism time, the individual impact on each woman, and what we can do as experts to reduce morbidity and provide quality of life. This natural process in the female life cycle has been of concern to women after menopause. Changes in different biophysical and psychosocial aspects, and their individual experiences, have repercussions on the lives of patients seeking specialized and multidisciplinary support to reduce the harmful effects of prolonged hypoestrogenism. Overweight and obesity, inadequate living habits and the presence of multi-morbidities cause damage to the quality of life and impact the functional capacity. Behavioral prescription and hormone therapy are among the treatments given to ease symptoms and reduce morbidity. A better understanding of these factors can help identify groups that require more care after menopause.

  3. The Solar Cycle

    Directory of Open Access Journals (Sweden)

    David H. Hathaway

    2015-09-01

    Full Text Available The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl (even-odd Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24.

  4. Exploring cycle crash characteristics in Malaysia

    Directory of Open Access Journals (Sweden)

    Hamzah A.

    2017-01-01

    Full Text Available This paper explains the cycle road crash trend, characteristics and injuries in Malaysia. It analyses the in-depth road crash investigation data collected by the Royal Malaysian Police which was made available to MIROS crash database. Fatality data was utilized due to its consistency. Cycle casualties reflected a continual downward pattern for year 2009 to 2014 in which the number of cycle crash involvement reduced by 49% and fatalities dropped by 42%. Among the prevalent factors of cycle fatalities are >60 age group, federal and state roads and straight road sections, rural and small towns, evening peak hours, and mainly involving cars and motorcycles. It is hoped that all these information would spark interests to improve cycle safety in Malaysia.

  5. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  6. Vuilleumier Cycle Cryogenic Refrigeration

    Science.gov (United States)

    1976-04-01

    changing pressure to produce a cooling effect is similar to that of the cold section of the Stirling cycle refrigerator , since the method by which the...AFFDL-TR-76-17 VUILLEUMIER CYCLE CRYOGENIC REFRIGERATION ENVIRONMENTAL CONTROL BRANCH 4 VEHICLE EQUIPMENT DIVISION APRIL 1976 TECHNICAL REPORT AFFDL...WORDS (Continue on reverse side if necessary and identify by block number) Cryogenic Refrigerator Vuilleumier Cycle 20. ABSTRACT (Continue on reverse

  7. [Cycling in Zagreb].

    Science.gov (United States)

    Matos, Stipan; Krapac, Ladislav; Krapac, Josip

    2007-01-01

    Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

  8. The nitrogen cycle

    National Research Council Canada - National Science Library

    Stein, Lisa Y; Klotz, Martin G

    2016-01-01

    .... Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions...

  9. Edgeworth cycles revisited

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Joseph [MIT Sloan School of Management, 50 Memorial Drive, E52-447, Cambridge MA 02142 (United States); Muehlegger, Erich [John F. Kennedy School of Government, Harvard University, Mailbox 25, 79 JFK Street, Cambridge, MA 02138 (United States); Samphantharak, Krislert [Graduate School of International Relations and Pacific Studies, University of California at San Diego, 9500 Gilman Drive 1519, La Jolla, CA 92093 (United States)

    2010-05-15

    Some gasoline markets exhibit remarkable price cycles, where price spikes are followed by a series of small price declines: a pattern consistent with a model of Edgeworth cycles described by Maskin and Tirole. We extend the model and empirically test its predictions with a new dataset of daily station-level prices in 115 US cities. Consistent with the theory, and often in contrast with previous empirical work, we find the least and most concentrated markets are much less likely to exhibit cycling behavior both within and across cities; areas with more independent convenience-store gas stations are also more likely to cycle. (author)

  10. Universal cycle periods

    NARCIS (Netherlands)

    Groot, de E.A. (Bert); Franses, P.H.P.H.

    2009-01-01

    We present a meta-analysis of cycles in historical economic data. The literature on stochastic and deterministic cycles in variables such as the consumer price index, employment, interest rates, commodity prices, and GDP is huge and scattered, but our meta-analysis reveals various communalities. Our

  11. Stability through cycles

    NARCIS (Netherlands)

    Groot, de E.A. (Bert); Franses, P.H.P.H.

    2006-01-01

    Economic variables like GDP growth, employment, interest rates and consumption show signs of cyclical behavior. Many variables display multiple cycles, with lengths ranging in between 5 to even up to 100 years. We argue that multiple cycles can be associated with long-run stability of the economic

  12. Life Cycle Environmental Management

    DEFF Research Database (Denmark)

    Pedersen, Claus Stig; Jørgensen, Jørgen; Pedersen, Morten Als

    1996-01-01

    processes. The discipline of life cycle environmental management (LCEM) focuses on the incorporation of environmental criteria from the life cycles of products and other company activities into the company management processes. This paper introduces the concept of LCEM as an important element...

  13. Teaching the Krebs Cycle.

    Science.gov (United States)

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  14. Rock Cycle Roulette.

    Science.gov (United States)

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  15. Life Cycle Impact Assessment

    DEFF Research Database (Denmark)

    Rosenbaum, Ralph K.; Hauschild, Michael Zwicky; Boulay, Anne-Marie

    2017-01-01

    This chapter is dedicated to the third phase of an LCA study, the Life Cycle Impact Assessment (LCIA) where the life cycle inventory’s information on elementary flows is translated into environmental impact scores. In contrast to the three other LCA phases, LCIA is in practice largely automated...

  16. Life cycle management (LCM)

    DEFF Research Database (Denmark)

    Remmen, Arne; Thrane, Mikkel

    2004-01-01

    The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels.......The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels....

  17. Seeing the Carbon Cycle

    Science.gov (United States)

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  18. The carbon cycle revisited

    Science.gov (United States)

    Bolin, Bert; Fung, Inez

    1992-01-01

    Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

  19. Power Plant Cycling Costs

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  20. Developmental Changes in Ultradian Sleep Cycles across Early Childhood.

    Science.gov (United States)

    Lopp, Sean; Navidi, William; Achermann, Peter; LeBourgeois, Monique; Diniz Behn, Cecilia

    2017-02-01

    Nocturnal human sleep is composed of cycles between rapid eye movement (REM) sleep and non-REM (NREM) sleep. In adults, the structure of ultradian cycles between NREM and REM sleep is well characterized; however, less is known about the developmental trajectories of ultradian sleep cycles across early childhood. Cross-sectional studies indicate that the rapid ultradian cycling of active-quiet sleep in infancy shifts to a more adult-like pattern of NREM-REM sleep cycling by the school-age years, yet longitudinal studies elucidating the details of this transition are scarce. To address this gap, we examined ultradian cycling during nocturnal sleep following 13 h of prior wakefulness in 8 healthy children at 3 longitudinal points: 2Y (2.5-3.0 years of age), 3Y (3.5-4.0 years of age), and 5Y (5.5-6.0 years of age). We found that the length of ultradian cycles increased with age as a result of increased NREM sleep episode duration. In addition, we observed a significant decrease in the number of NREM sleep episodes as well as a nonsignificant trend for a decrease in the number of cycles with increasing age. Together, these findings suggest a concurrent change in which cycle duration increases and the number of cycles decreases across development. We also found that, consistent with data from adolescents and adults, the duration of NREM sleep episodes decreased with time since lights-off whereas the duration of REM sleep episodes increased over this time period. These results indicate the presence of circadian modulation of nocturnal sleep in preschool children. In addition to characterizing changes in ultradian cycling in healthy children ages 2 to 5 years, this work describes a developmental model that may provide insights into the emergence of normal adult REM sleep regulatory circuitry as well as potential trajectories of dysregulated ultradian cycles such as those associated with affective disorders.

  1. Adiposity Measures and Menstrual Cycle: Do We Envisage a Relation?

    Directory of Open Access Journals (Sweden)

    Rashmi Sinha

    2011-01-01

    Full Text Available The study aims to see the relationship between menstrual cycle and adiposity measures in Indian populations as menstrual cycle length has an important bearing on fertility and health of women. 415 premenopausal women in the ages 22–50 years residing in Delhi, India constituted the data. The adiposity was assessed by BMI as well as by using Bio-electric impedance method. The information regarding their physical activity pattern and menstrual cycle was recorded, and age at menarche was obtained through recall method. None of the underweight category women had menstrual cycle of less than 25 days. A decrease in body mass index and an increase in the age at menarche were found with the increase in the duration of menstrual cycle. The majority of women with 25–35 days duration of menstrual cycle in the present study were distributed in all the categories of BMI. Age was found to have no effect on longer cycle. The majority of women were in moderately physically active group and experienced menstrual cycle duration of 25–35 days. It is of utmost importance to identify the effects of moderate levels of physical activity, body mass index, and age at menarche on the menstrual cycle to enable the normal reproductive health of women.

  2. Applied physiology of cycling.

    Science.gov (United States)

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  3. Symbiotic Origin of Aging.

    Science.gov (United States)

    Greenberg, Edward F; Vatolin, Sergei

    2017-09-25

    Normally aging cells are characterized by an unbalanced mitochondrial dynamic skewed toward punctate mitochondria. Genetic and pharmacological manipulation of mitochondrial fission/fusion cycles can contribute to both accelerated and decelerated cellular or organismal aging. In this work, we connect these experimental data with the symbiotic theory of mitochondrial origin to generate new insight into the evolutionary origin of aging. Mitochondria originated from autotrophic α-proteobacteria during an ancient endosymbiotic event early in eukaryote evolution. To expand beyond individual host cells, dividing α-proteobacteria initiated host cell lysis; apoptosis is a product of this original symbiont cell lytic exit program. Over the course of evolution, the host eukaryotic cell attenuated the harmful effect of symbiotic proto-mitochondria, and modern mitochondria are now functionally interdependent with eukaryotic cells; they retain their own circular genomes and independent replication timing. In nondividing differentiated or multipotent eukaryotic cells, intracellular mitochondria undergo repeated fission/fusion cycles, favoring fission as organisms age. The discordance between cellular quiescence and mitochondrial proliferation generates intracellular stress, eventually leading to a gradual decline in host cell performance and age-related pathology. Hence, aging evolved from a conflict between maintenance of a quiescent, nonproliferative state and the evolutionarily conserved propagation program driving the life cycle of former symbiotic organisms: mitochondria.

  4. Life Cycle Management

    DEFF Research Database (Denmark)

    Bey, Niki

    2017-01-01

    This chapter gives an overview of Life Cycle Management (LCM)—a discipline that deals with the managerial tasks related to practicing sustainable development in an organisation . Just as Life Cycle Assessment, LCM advocates the life cycle perspective , and it applies this perspective in decision......-making processes. The chapter shows that LCA can play a key role in LCM since LCA provides quantitative performance measurements. It also explains, which stakeholders need to be considered, how LCA and LCM relate, how LCA can be used to develop Key Performance Indicators, and addresses how LCM can be integrated...

  5. Political Budget Cycles

    DEFF Research Database (Denmark)

    Aaskoven, Lasse; Lassen, David Dreyer

    2017-01-01

    The political budget cycle—how elections affect government fiscal policy—is one of the most studied subjects in political economy and political science. The key theoretical question is whether incumbent governments can time or structure public finances in ways that improve their chances...... on political budget cycles have recently focused on conditions under which such cycles are likely to obtain. Much recent research focuses on subnational settings, allowing comparisons of governments in similar institutional environments, and a consensus on the presences of cycles in public finances......—and in the reporting of public finances—is beginning to emerge....

  6. Joy, Exercise, Enjoyment, Getting out: A Qualitative Study of Older People's Experience of Cycling in Sydney, Australia

    OpenAIRE

    Alexis Zander; Erin Passmore; Chloe Mason; Chris Rissel

    2013-01-01

    Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack...

  7. Product Life Cycle Planning

    National Research Council Canada - National Science Library

    Walaszek, Jeffrey

    2003-01-01

    .... This phase of work was undertaken to: (1) provide guidelines, technical support, and planning approaches for researchers that result in realistic life cycle plans for products emerging from the RSM...

  8. The Rock Cycle

    Science.gov (United States)

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  9. Cycles in graphs

    CERN Document Server

    Alspach, BR

    1985-01-01

    This volume deals with a variety of problems involving cycles in graphs and circuits in digraphs. Leading researchers in this area present here 3 survey papers and 42 papers containing new results. There is also a collection of unsolved problems.

  10. Traffic Signal Cycle Lengths

    Data.gov (United States)

    Town of Chapel Hill, North Carolina — Traffic signal location list for the town of Chapel Hill. This data set includes light cycle information as well as as intersection information.The Town of Chapel...

  11. Life Cycle Costing.

    Science.gov (United States)

    McCraley, Thomas L.

    1985-01-01

    Life cycle costing establishes a realistic comparison of the cost of owning and operating products. The formula of initial cost plus maintenance plus operation divided by useful life identifies the best price over the lifetime of the product purchased. (MLF)

  12. Solar Cycle Prediction

    Directory of Open Access Journals (Sweden)

    Kristóf Petrovay

    2010-12-01

    Full Text Available A review of solar cycle prediction methods and their performance is given, including forecasts for cycle 24. The review focuses on those aspects of the solar cycle prediction problem that have a bearing on dynamo theory. The scope of the review is further restricted to the issue of predicting the amplitude (and optionally the epoch of an upcoming solar maximum no later than right after the start of the given cycle. Prediction methods form three main groups. Precursor methods rely on the value of some measure of solar activity or magnetism at a specified time to predict the amplitude of the following solar maximum. Their implicit assumption is that each numbered solar cycle is a consistent unit in itself, while solar activity seems to consist of a series of much less tightly intercorrelated individual cycles. Extrapolation methods, in contrast, are based on the premise that the physical process giving rise to the sunspot number record is statistically homogeneous, i.e., the mathematical regularities underlying its variations are the same at any point of time and, therefore, it lends itself to analysis and forecasting by time series methods. Finally, instead of an analysis of observational data alone, model based predictions use physically (more or less consistent dynamo models in their attempts to predict solar activity. In their overall performance during the course of the last few solar cycles, precursor methods have clearly been superior to extrapolation methods. Nevertheless, most precursor methods overpredicted cycle 23, while some extrapolation methods may still be worth further study. Model based forecasts have not yet had a chance to prove their skills. One method that has yielded predictions consistently in the right range during the past few solar cycles is that of K. Schatten et al., whose approach is mainly based on the polar field precursor. The incipient cycle 24 will probably mark the end of the Modern Maximum, with the Sun

  13. The glacial cycles and cosmic rays

    CERN Document Server

    Kirkby, Jasper; Müller, R A

    2004-01-01

    The cause of the glacial cycles remains a mystery. The origin is widely accepted to be astronomical since paleoclimatic archives contain strong spectral components that match the frequencies of Earth's orbital modulation. Milankovitch insolation theory contains similar frequencies and has become established as the standard model of the glacial cycles. However, high precision paleoclimatic data have revealed serious discrepancies with the Milankovitch model that fundamentally challenge its validity and re-open the question of what causes the glacial cycles. We propose here that the ice ages are initially driven not by insolation cycles but by cosmic ray changes, probably through their effect on clouds. This conclusion is based on a wide range of evidence, including results presented here on speleothem growth in caves in Austria and Oman, and on a record of cosmic ray flux over the past 220 kyr obtained from the 10Be composition of deep-ocean sediments.

  14. Menstrual Cycle: Basic Biology

    OpenAIRE

    Hawkins, Shannon M.; Matzuk, Martin M.

    2008-01-01

    The basic biology of the menstrual cycle is a complex, coordinated sequence of events involving the hypothalamus, anterior pituitary, ovary, and endometrium. The menstrual cycle with all its complexities can be easily perturbed by environmental factors such as stress, extreme exercise, eating disorders, and obesity. Furthermore, genetic influences such as fragile X premutations (Chapter X), X chromosome abnormalities (Chapter X), and galactose-1-phosphate uridyltransferase (GALT) point mutati...

  15. Evaluation of light/dark cycle in anxiety- and depressive-like behaviors after regular treatment with methylphenidate hydrochloride in rats of different ages Avaliação do ciclo claro e escuro no comportamento relacionado à ansiedade e à depressão em ratos de diferentes idades após tratamento crônico com hidrocloridrato de metilfenidato

    Directory of Open Access Journals (Sweden)

    Karin M. Gomes

    2011-03-01

    Full Text Available OBJECTIVE: Methylphenidate hydrochloride is the most widely used medication for treatment and management of attention-deficit hyperactivity disorder. However, the chronic effects of methylphenidate hydrochloride on anxiety- and depressive-like rat behaviors remain poorly investigated. In this context, the present study evaluated the effects of treatment with methylphenidate hydrochloride on anxiety- and depressive-like behaviors using young and adult rats during the light and the dark cycle. METHOD: Male Wistar rats (25 or 60 days old received a once-daily (in either the light or dark cycle methylphenidate hydrochloride (2mg/kg or saline intraperitoneal injection for 28 days. We performed elevated plus maze and forced swimming test two hours after the last injection. RESULTS: The light/dark cycle was a significant factor in the anxiety-like behaviors; however, no significant interaction between all three factors (cycle, age and methylphenidate hydrochloride was found. Nevertheless, we observed a nominally significant interaction between the light/ dark cycle and age in the forced swimming test. CONCLUSION: Our results have shown that age and the light/dark cycle are more significant modulators of anxiety- and depressive-like behaviors than methylphenidate hydrochloride treatment.OBJETIVO: Hidrocloridrato de metilfenidato é a medicação preferida para o tratamento e manutenção do transtorno de atenção e hiperatividade. No entanto, os efeitos do tratamento crônico com hidrocloridrato de metilfenidato em diferentes idades e ciclos sobre o comportamento relacionado à ansiedade e à depressão ainda não está claro. Neste contexto, o presente estudo teve como objetivo avaliar os efeitos do tratamento com hidrocloridrato de metilfenidato sobre o comportamento relacionado à ansiedade e à depressão em diferentes idades e no ciclo claro e escuro. MÉTODO: Foram utilizados ratos Wistar machos jovens e adultos que receberam uma vez ao dia

  16. Quantifying the Adaptive Cycle.

    Directory of Open Access Journals (Sweden)

    David G Angeler

    Full Text Available The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011 data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  17. Quantifying the adaptive cycle

    Science.gov (United States)

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  18. Rapid Cycling and Its Treatment

    Science.gov (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

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

    Science.gov (United States)

    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.

  20. Age Spots

    Science.gov (United States)

    ... Hands Age Spots Aging Skin Birthmarks Burn Scars Cellulite Crow's Feet Droopy Eyelids Excess Fat Excessive Sweating ... Hands Age Spots Aging Skin Birthmarks Burn Scars Cellulite Crow's Feet Droopy Eyelids Excess Fat Excessive Sweating ...

  1. Helium process cycle

    Science.gov (United States)

    Ganni, Venkatarao

    2008-08-12

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  2. Sex Roles and Depression in Middle Age.

    Science.gov (United States)

    Broschart, Kay Richards

    Middle age is a phase of the life cycle marked by poorly defined boundaries and declining status. Studies reveal that depression is more likely to occur during middle age than during any other phase of the life cycle. In addition, research has verified that depression occurs more commonly in women than men. A sociological analysis of factors which…

  3. The global sulfur cycle

    Science.gov (United States)

    Sagan, D. (Editor)

    1985-01-01

    The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

  4. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  5. Revenue cycle management.

    Science.gov (United States)

    Manley, Ray; Satiani, Bhagwan

    2009-11-01

    With the widening gap between overhead expenses and reimbursement, management of the revenue cycle is a critical part of a successful vascular surgery practice. It is important to review the data on all the components of the revenue cycle: payer contracting, appointment scheduling, preregistration, registration process, coding and capturing charges, proper billing of patients and insurers, follow-up of accounts receivable, and finally using appropriate benchmarking. The industry benchmarks used should be those of peers in identical groups. Warning signs of poor performance are discussed enabling the practice to formulate a performance improvement plan.

  6. Supercapacitor Degradation Assesment by Power Cycling and Calendar Life Tests

    Directory of Open Access Journals (Sweden)

    Sedlakova Vlasta

    2016-09-01

    Full Text Available Degradation of Supercapacitors (SC is quantified by accelerated ageing tests. Energy cycling tests and calendar life tests are used since they address the real operating modes. The periodic characterization is used to analyse evolution of the SC parameters as a whole, and its Helmholtz and diffusion capacitances. These parameters are determined before the ageing tests and during 3 × 105 cycles of both 75% and 100% energy cycling, respectively. Precise evaluation of the capacitance and Equivalent Series Resistance (ESR is based on fitting the experimental data by an exponential function of voltage vs. time. The ESR increases linearly with the number (No of cycles for both 75% and 100% energy cycling, whereas a super-linear increase of ESR vs. time of cycling is observed for the 100% energy cycling. A decrease of capacitance in time had been evaluated for 2000 hours of ageing of SC. A relative change of capacitance is ΔC/C0 = 16% for the 75% energy cycling test and ΔC/C0 = 20% for the 100% energy cycling test at temperature 25°C, while ΔC/C0 = 6% for the calendar test at temperature 22°C for a voltage bias V = 1.0 Vop. The energy cycling causes a greater decrease of capacitance in comparison with the calendar test; such results may be a consequence of increasing the temperature due to the Joule heat created in the SC structure. The charge/discharge current value is the same for both 75% and 100% energy cycling tests, so it is the Joule heat created on both the equivalent series resistance and time-dependent diffuse resistance that should be the source of degradation of the SC structure. The diffuse resistance reaches a value of up to 30Ω within each 75% energy cycle and up to about 43Ω within each 100% energy cycle.

  7. Finite time thermodynamics of power and refrigeration cycles

    CERN Document Server

    Kaushik, Shubhash C; Kumar, Pramod

    2017-01-01

    This book addresses the concept and applications of Finite Time Thermodynamics to various thermal energy conversion systems including heat engines, heat pumps, and refrigeration and air-conditioning systems. The book is the first of its kind, presenting detailed analytical formulations for the design and optimisation of various power producing and cooling cycles including but not limited to: • Vapour power cycles • Gas power cycles • Vapour compression cycles • Vapour absorption cycles • Rankine cycle coupled refrigeration systems Further, the book addresses the thermoeconomic analysis for the optimisation of thermal cycles, an important field of study in the present age and which is characterised by multi-objective optimization regarding energy, ecology, the environment and economics. Lastly, the book provides the readers with key techniques associated with Finite Time Thermodynamics, allowing them to understand the relevance of irreversibilitie s associated with real processes and the scientific r...

  8. Diferencias de género en las edades del ciclo vital de 65 años y más en el municipio Guanabacoa Gender differences in 65 years life cycle age and more in Guanabacoa municipality

    Directory of Open Access Journals (Sweden)

    Ileana Castañeda Abascal

    2009-12-01

    énero fueron menores, y se correspondió con el «Índice de igualdad 65 años y más» (II 65 y más con valor más elevado, opuesto totalmente al consultorio de condiciones de vida desfavorables, en el que se registraron las mayores diferencias de género y el «Índice de igualdad 65 años y más» (II 65 y más fue el menor. Los aspectos de la vida que marcaron la mayor diferencia en este último consultorio fueron: labores en el hogar, jubilación, maltrato y salud.Introduction: Gender could be known like the social, cultural, politic, psychological, legal and economic features set associated with persons in a different way according to sex. Gender inequalities increase with age affecting the elderly health. The gender approach in this research proposes to attract the attention on determined features of reality where there are inequalities frequently ignored and affecting the elderly (men and women health in Guanabacoa municipality. Objectives: To identify the gender differences according to life conditions in 65 age group and more in this municipality from January, 2006 to February, 2007, and to determine the modifiable factors contributing to gender disparity, in the consulting room more affected by these inequalities. Methods: In a first stage, a descriptive study was conducted to classify in a debatable way three territories according the life conditions selecting among them one by randomized simple sampling. Gender differences were identified through synthetic indicator designed in Public Health National School called "Equality Rate of 65 years old or more" (II 65 and more; and in a second stage we made a group discussion technique with community social representatives to identify life features in which it is possible to decrease the gender differences. Priority matrix allowed us to identify among those life features those more modifiable by means of a strategy of educational intervention. Results: There were differences among women and men in the three consulting

  9. Development of peak performance in track cycling.

    Science.gov (United States)

    Schumacher, Y O; Mueller, P; Keul, J

    2001-06-01

    Retrospective analysis of peak performances can be a usefull tool for the estimation of future trends in high performance sports. The purpose of this study was to investigate the evolution of performance in track cycling from 1979 to 1999 and to asses age- and gender-related differences. We studied the results of the world track cycling championships for this period in 200 m, 1000 m, individual and team pursuit races for elite and junior athletes. Overall trends, performance differences between rank 1 and 5, gender- and age-related differences were calculated. They show a significant (ptrack cycling endurance disciplines. New technical developments show no statistical significant impact. The performance gap between male and female athletes is constant, independent of discipline or race distance and comparable to observations in other sports. Age-related differences in performance is most visible in disciplines requiring short, high intensity power output. Based on these data, estimation of possible winning times and adaptation of training programs for future track cycling competitions might be facilitated.

  10. 5 KPIs that require revenue cycle managers' attention.

    Science.gov (United States)

    Saharia, Devendra

    2014-09-01

    Revenue cycle leaders can gain the clearest insight into their organizations' revenue cycle performance by focusing in particular on five key performance indicators: Cash ratio. Medicare-billed accounts receivable (A/R) over 30 days as a percentage of total Medicare A/R. Third-party aging over 90 days. Bad debt expense. Customer experience.

  11. Menstrual cycle pattern and fertility

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

    1999-01-01

    To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss.......To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss....

  12. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    2009-01-01

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...

  13. THE EUROPEAN BUSINESS CYCLE

    Directory of Open Access Journals (Sweden)

    Ignat Ion

    2009-05-01

    Full Text Available The construction of European Monetary Union has raised several questions about the existence of a common business cycle, a European one. The lack of cyclical synchronization would complicate the monetary and fiscal policies in the Union, being a negative

  14. Reasoning with Causal Cycles

    Science.gov (United States)

    Rehder, Bob

    2017-01-01

    This article assesses how people reason with categories whose features are related in causal cycles. Whereas models based on causal graphical models (CGMs) have enjoyed success modeling category-based judgments as well as a number of other cognitive phenomena, CGMs are only able to represent causal structures that are acyclic. A number of new…

  15. LIFE-CYCLE ASSESSMENT

    Science.gov (United States)

    Life Cycle Assessment, or LCA, is an environmental accounting and mangement approach that consider all the aspects of resource use and environmental releases associated with an industrial system from cradle-to-grave. Specifically, it is a holistic view of environmental interacti...

  16. The Degree Cycle

    DEFF Research Database (Denmark)

    Wood, Johanna

    2016-01-01

    The grammaticalization of the demonstratives this, that and thus are investigated with respect to their functions as degree adverbs using empirical data from dictionaries and historical and modern corpora. It is first argued that thus participates in the CP cycle. With respect to this and that...

  17. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...

  18. Econometric Business Cycle Research

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1940-01-01

    textabstractAlso published in: G. Haberler (Ed.), Readings in Business Cycles Theory, Blakiston, Philadelphia, 1944, pp. 61-86, in: Adrian C. Darnell (Ed.), The History of Econometrics, Vol. 2, Edward Elgar, Aldershot, 1994, pp. 230-247 and in: David F. Hendry and Mary S. Morgan (Eds), The

  19. Assisted Cycling Tours

    Science.gov (United States)

    Hollingsworth, Jan Carter

    2008-01-01

    This article discusses Assisted Cycling Tours (ACT), a Westminster, Colorado based 501(c)3, non-profit that is offering the joy of bicycle tours in breathtaking, scenic locations to children and adults with developmental and physical disabilities and their families. ACT was founded by Bob Matter and his son David with a goal of opening up the…

  20. Mosquito Life Cycle

    Science.gov (United States)

    Knowing the stages of the mosquito's life will help you prevent mosquitoes around your home and help you choose the right pesticides for your needs, if you decide to use them. All mosquito species go through four distinct stages during their live cycle.

  1. Big Data and Cycling

    NARCIS (Netherlands)

    Romanillos, Gustavo; Zaltz Austwick, Martin; Ettema, Dick; De Kruijf, Joost

    2016-01-01

    Big Data has begun to create significant impacts in urban and transport planning. This paper covers the explosion in data-driven research on cycling, most of which has occurred in the last ten years. We review the techniques, objectives and findings of a growing number of studies we have classified

  2. The Pneumocystis life cycle

    Directory of Open Access Journals (Sweden)

    Cécile-Marie Aliouat-Denis

    2009-05-01

    Full Text Available First recognised as "schizonts" of Trypanosoma cruzi, Pneumocystis organisms are now considered as part of an early-diverging lineage of Ascomycetes. As no robust long-term culture model is available, most data on the Pneumocystis cell cycle have stemmed from ultrastructural images of infected mammalian lungs. Although most fungi developing in animals do not complete a sexual cycle in vivo, Pneumocystis species constitute one of a few exceptions. Recently, the molecular identification of several key players in the fungal mating pathway has provided further evidence for the existence of conjugation and meiosis in Pneumocystisorganisms. Dynamic follow-up of stage-to-stage transition as well as studies of stage-specific proteins and/or genes would provide a better understanding of the still hypothetical Pneumocystislife cycle. Although difficult to achieve, stage purification seems a reasonable way forward in the absence of efficient culture systems. This mini-review provides a comprehensive overview of the historical milestones leading to the current knowledge available on the Pneumocystis life cycle.

  3. Life Cycle Collection Management

    Directory of Open Access Journals (Sweden)

    Helen Shenton

    2003-09-01

    Full Text Available Life cycle collection management is a way of taking a long-term approach to the responsible stewardship of the British Library's collections and is one of the Library's strategic strands. It defines the different stages in a collection item's existence over time. These stages range from selection and acquisitions processing, cataloguing and press marking, through to preventive conservation, storage and retrieval. Life cycle collection management seeks to identify the costs of each stage in order to show the economic interdependencies between the phases over time. It thereby aims to demonstrate the long-term consequences of what the library takes into its collections, by making explicit the financial and other implications of decisions made at the beginning of the life cycle for the next 100 plus years. This paper describes the work over the past year at the British Library on this complex and complicated subject. It presents the emerging findings and suggests how it can be used for practical reasons (by individual curators and selectors and for economic, governance and political purposes. The paper describes the next steps in the project, for example, on a predictive data model. The British Library is seeking to benchmark itself against comparable organisations in this area. It intends to work with others on specific comparison for example, of life cycle costing of electronic and paper journals, as a prelude to eliding digital and 'traditional' formats.

  4. Apoptosis and cell cycle

    Directory of Open Access Journals (Sweden)

    Petrović Marija

    2014-01-01

    Full Text Available Apoptosis, a form of programmed cell death, is used to eliminate individual cells surrounded by normal cell population. It is a controlled way of cell death in which the cell actively participates by conducting precise, gene-regulated program of self-destruction, that is, cell 'suicide.' Active synthesis of macromolecules is necessary during this process. Death of individual cells is necessary to maintain a balance in living systems, so the process of apoptosis is continuously present in the body, which allows normal development, tissue homeostasis, and many other physiological processes. The molecular mechanisms that regulate apoptosis are functionally linked to other cellular mechanisms, such as control of the cell cycle, cell proliferation and differentiation, genomic stability and cellular metabolism. Damage to the DNA molecule, caused both spontaneously and under the influence of various chemical and physical agents, leads to the cell cycle arrest and activation of mechanisms that repair the damage. Depending on the type and extent of the damage, the cell either continues progression through the cell cycle, or activates the mechanisms that lead to apoptosis. Disturbances in the regulation of apoptosis and cell cycle present the molecular and biological basis of many diseases. Because of the importance of these processes during the development and progression of tumors, their use as biological markers is one of the main strategies in the formation of therapeutic approaches for the treatment of cancer.

  5. Privatization and nationalization cycles

    OpenAIRE

    Chang, Roberto; Hevia, Constantino; Loayza, Norman

    2009-01-01

    This paper studies the cycles of nationalization and privatization in resource-rich economies as a prime instance of unstable institutional reform. The authors discuss the available evidence on the drivers and consequences of privatization and nationalization, review the existing literature, and present illustrative case studies. This leads to the main contribution of the paper: a static a...

  6. Re-Cycling

    Science.gov (United States)

    Brown, Robert W.; Covault, Corbin E.

    2015-01-01

    An old comedy routine on Saturday Night Live by Father Guido Sarducci introduced a "Five-Minute University," because five minutes is all that's remembered after graduation anyway. In counterpoint, we discuss "cycling," a teaching method for memory enhancement. Our principal implementation consists of offering a simple version…

  7. The Science of Cycling

    Science.gov (United States)

    Crompton, Zoe; Daniels, Shelley

    2014-01-01

    Children are engaged by finding out about science in the real world (Harlen, 2010). Many children will be cyclists or will have seen or heard about the success of British cyclists in the Olympics and the Tour de France. This makes cycling a good hook to draw children into learning science. It is also a good cross-curricular topic, with strong…

  8. The Geologic Nitrogen Cycle

    Science.gov (United States)

    Johnson, B. W.; Goldblatt, C.

    2013-12-01

    N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

  9. Rural Aging

    Science.gov (United States)

    ... Rural Health Topics & States Topics View more Rural Aging The nation's population is aging, and with that change comes increased healthcare needs. ... Disease Control and Prevention report, The State of Aging and Health in America 2013 , the population 65 ...

  10. Archaea in biogeochemical cycles.

    Science.gov (United States)

    Offre, Pierre; Spang, Anja; Schleper, Christa

    2013-01-01

    Archaea constitute a considerable fraction of the microbial biomass on Earth. Like Bacteria they have evolved a variety of energy metabolisms using organic and/or inorganic electron donors and acceptors, and many of them are able to fix carbon from inorganic sources. Archaea thus play crucial roles in the Earth's global geochemical cycles and influence greenhouse gas emissions. Methanogenesis and anaerobic methane oxidation are important steps in the carbon cycle; both are performed exclusively by anaerobic archaea. Oxidation of ammonia to nitrite is performed by Thaumarchaeota. They represent the only archaeal group that resides in large numbers in the global aerobic terrestrial and marine environments on Earth. Sulfur-dependent archaea are confined mostly to hot environments, but metal leaching by acidophiles and reduction of sulfate by anaerobic, nonthermophilic methane oxidizers have a potential impact on the environment. The metabolisms of a large number of archaea, in particular those dominating the subsurface, remain to be explored.

  11. Life Cycle Sustainability Dashboard

    DEFF Research Database (Denmark)

    Traverso, Marzia; Finkbeiner, Matthias; Jørgensen, Andreas

    2012-01-01

    One method to assess the sustainability performance of products is life cycle sustainability assessment (LCSA), which assesses product performance considering the environmental,economic, and social dimensions of the life cycle. The results of LCSA can be used to compare different products...... or to support decision making toward sustainable production and consumption. In both cases, LCSA results could be too disaggregated and consequently too difficult to understand and interpret by decision makers. As non-experts are usually the target audience of experts and scientists, and are also involved...... in decision-making processes, the necessity for a straightforward but comprehensive presentation of LCSA results is becoming strategically important. The implementation of the dashboard of sustainability proposed in this article offers a possible solution. An outstanding characteristic of the dashboard...

  12. Characteristics of track cycling.

    Science.gov (United States)

    Craig, N P; Norton, K I

    2001-01-01

    Track cycling events range from a 200 m flying sprint (lasting 10 to 11 seconds) to the 50 km points race (lasting approximately 1 hour). Unlike road cycling competitions where most racing is undertaken at submaximal power outputs, the shorter track events require the cyclist to tax maximally both the aerobic and anaerobic (oxygen independent) metabolic pathways. Elite track cyclists possess key physical and physiological attributes which are matched to the specific requirements of their events: these cyclists must have the appropriate genetic predisposition which is then maximised through effective training interventions. With advances in technology it is now possible to accurately measure both power supply and demand variables under competitive conditions. This information provides better resolution of factors that are important for training programme design and skill development.

  13. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    In 1845, the French chemist and mining engineer Jacques-Joseph Ebelman figured out why Earth's atmosphere contains oxygen (1). Oxygen is produced by plants during photosynthesis, but almost all of this oxygen is used again in respiration. Ebelman reasoned that small amounts of organic matter rema...... geochemical cycle. But Earth is an old planet, and oxygen levels have changed through time (2). On page 540 of this issue, Schrag et al. (3) challenge the most commonly used geochemical approach to assess long-term changes in the coupled oxygen and carbon cycles....... remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen...

  14. Cycling and erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Ina Šibli

    2015-01-01

    Full Text Available Abstract: For many years medical studies have implicated bicycle riding is causing erectile dysfunction (ED in association with higher perineal pressure. This review focuses upon epidemiological studies assesing the impact of cycling on ED, pathogenesis of ED in cyclists  as well as on research considering changes of perineal pressure, hemodynamics, and nerve conduction when cycling. Investigestors were also interested in different saddle sizes, materials and geometry and also in the impact of saddle and riders position on changes to the perineum. Research on female cyclists is very limited but indicates similar genitourinary disorders as in male cyclists. We also review  research on preventative and therapeutic options regarding bicycle riding and ED.

  15. [Microbial geochemical calcium cycle].

    Science.gov (United States)

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  16. Unemployment and Business Cycles

    OpenAIRE

    Lawrence J. Christiano; Martin Eichenbaum; Mathias Trabandt

    2013-01-01

    We develop and estimate a general equilibrium search and matching model that accounts for key business cycle properties of macroeconomic aggregates, including labor market variables. In sharp contrast to leading New Keynesian models, we do not impose wage inertia. Instead we derive wage inertia from our specification of how firms and workers negotiate wages. Our model outperforms a variant of the standard New Keynesian Calvo sticky wage model. According to our estimated model, there is a crit...

  17. Skills, sunspots and cycles

    DEFF Research Database (Denmark)

    Busato, Francesco; Marchetti, Enrico

    This paper explores the ability of a class of one-sector,multi-input models to generate indeterminate equilibrium paths, andendogenous cycles, without relying on factors' hoarding. The modelpresents a novel theoretical economic mechanism that supportssunspot-driven expansions without requiring...... upward sloping labordemand schedules. Its distinctive characteristic is that the skillcomposition of aggregate labor demand drives expansionary i.i.d.demand shocks. Next, the model explains the labor market dynamicsfrom the supply side, while endogenizing the capital productivityresponse to changes...

  18. Injuries in Competitive Cycling.

    Science.gov (United States)

    Bohlmann, J T

    1981-05-01

    In brief: There are relatively few injuries in competitive cycling, and abrasions are the most common. In this study most injuries occurred to the left side of the cyclist, and most common causes were flat tires and colliding with other cyclists. The number of injuries decreased as the cyclist gained more experience. Preventive measures include keeping the bicycle in top mechanical condition, wearing strong, durable clothing and a helmet, and knowing how to fall.

  19. Centrifugal Gas Compression Cycle

    Science.gov (United States)

    Fultun, Roy

    2002-11-01

    A centrifuged gas of kinetic, elastic hard spheres compresses isothermally and without flow of heat in a process that reverses free expansion. This theorem follows from stated assumptions via a collection of thought experiments, theorems and other supporting results, and it excludes application of the reversible mechanical adiabatic power law in this context. The existence of an isothermal adiabatic centrifugal compression process makes a three-process cycle possible using a fixed sample of the working gas. The three processes are: adiabatic mechanical expansion and cooling against a piston, isothermal adiabatic centrifugal compression back to the original volume, and isochoric temperature rise back to the original temperature due to an influx of heat. This cycle forms the basis for a Thomson perpetuum mobile that induces a loop of energy flow in an isolated system consisting of a heat bath connectable by a thermal path to the working gas, a mechanical extractor of the gas's internal energy, and a device that uses that mechanical energy and dissipates it as heat back into the heat bath. We present a simple experimental procedure to test the assertion that adiabatic centrifugal compression is isothermal. An energy budget for the cycle provides a criterion for breakeven in the conversion of heat to mechanical energy.

  20. Terrestrial Carbon Cycle Variability.

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2 , temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1 ) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1 ), and

  1. CANDU-6 fuel optimization for advanced cycles

    Energy Technology Data Exchange (ETDEWEB)

    St-Aubin, Emmanuel, E-mail: emmanuel.st-aubin@polymtl.ca; Marleau, Guy, E-mail: guy.marleau@polymtl.ca

    2015-11-15

    Highlights: • New fuel selection process proposed for advanced CANDU cycles. • Full core time-average CANDU modeling with independent refueling and burnup zones. • New time-average fuel optimization method used for discrete on-power refueling. • Performance metrics evaluated for thorium-uranium and thorium-DUPIC cycles. - Abstract: We implement a selection process based on DRAGON and DONJON simulations to identify interesting thorium fuel cycles driven by low-enriched uranium or DUPIC dioxide fuels for CANDU-6 reactors. We also develop a fuel management optimization method based on the physics of discrete on-power refueling and the time-average approach to maximize the economical advantages of the candidates that have been pre-selected using a corrected infinite lattice model. Credible instantaneous states are also defined using a channel age model and simulated to quantify the hot spots amplitude and the departure from criticality with fixed reactivity devices. For the most promising fuels identified using coarse models, optimized 2D cell and 3D reactivity device supercell DRAGON models are then used to generate accurate reactor databases at low computational cost. The application of the selection process to different cycles demonstrates the efficiency of our procedure in identifying the most interesting fuel compositions and refueling options for a CANDU reactor. The results show that using our optimization method one can obtain fuels that achieve a high average exit burnup while respecting the reference cycle safety limits.

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

    African Journals Online (AJOL)

    Enrique

    system.6,16,18,24 Mechanical disruption of muscle fibres caused by prolonged eccentric muscle activity has ... necrosis and inflammation occurred in muscle biopsies per- formed on runners after running a marathon ..... Nicol C, Komi PV, Marconnet P. Fatigue effects of marathon running on neuromuscular performance.

  3. Age-Related Differences in Bilateral Asymmetry in Cycling Performance

    Science.gov (United States)

    Liu, Ting; Jensen, Jody L.

    2012-01-01

    Bilateral asymmetry, a form of limb laterality in the context of moving two limbs, emerges in childhood. Children and adults show lateral preference in tasks that involve the upper and lower limbs. The importance of research in limb laterality is the insight it could provide about lateralized functions of the cerebral hemispheres. Analyzing…

  4. Battery cycling and calendar aging: year one testing results.

    Science.gov (United States)

    2016-07-01

    This report is meant to provide an update on the ongoing battery testing performed by the Hawaii Natural Energy Institute to evaluate Electric Vehicle (EV) battery durability and reliability under electric utility grid operations. Commercial EV batte...

  5. Reporting in vitro fertilization cycles to the Society for Assisted Reproductive Technology database: where have all the cycles gone?

    Science.gov (United States)

    Kulak, David; Jindal, Sangita K; Oh, Cheongeun; Morelli, Sara S; Kratka, Scott; McGovern, Peter G

    2016-04-01

    To assess the relationship between live birth rates (LBRs) and the incidence of under-reported cycles by IVF clinics. Cohort study. Not applicable. All patients undergoing IVF cycles in the aforementioned clinics. Not applicable. The reporting percentage (RP), defined as number of cycles with reported pregnancy rates divided by total cycles performed. Results from cryopreservation cycles are only presented by SART if an embryo transfer occurs. Thus, RP decreases as incidence of embryo or oocyte banking cycles increases. The LBRs in women aged Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  6. Menstrual cycle pattern and fertility

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

    1999-01-01

    OBJECTIVE: To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss. DESIGN: Prospective follow-up study. SETTING: Healthy couples recruited throughout Denmark...

  7. National Urea Cycle Disorders Foundation

    Science.gov (United States)

    ... INGESTING HIGH-PROTEIN FOODS AND PROTEIN SUPPLEMENTS FOR BODYBUILDING : Symptoms of urea cycle disorder went unrecognized as young mother, Meegan Hefford, prepared for a bodybuilding competition. Undiagnosed urea cycle disorders can be triggered ...

  8. GEOSS Water Cycle Integrator

    Science.gov (United States)

    Koike, Toshio; Lawford, Richard; Cripe, Douglas

    2013-04-01

    It is critically important to recognize and co-manage the fundamental linkages across the water-dependent domains; land use, including deforestation; ecosystem services; and food-, energy- and health-securities. Sharing coordinated, comprehensive and sustained observations and information for sound decision-making is a first step; however, to take full advantage of these opportunities, we need to develop an effective collaboration mechanism for working together across different disciplines, sectors and agencies, and thereby gain a holistic view of the continuity between environmentally sustainable development, climate change adaptation and enhanced resilience. To promote effective multi-sectoral, interdisciplinary collaboration based on coordinated and integrated efforts, the intergovernmental Group on Earth Observations (GEO) is implementing the Global Earth Observation System of Systems (GEOSS). A component of GEOSS now under development is the "GEOSS Water Cycle Integrator (WCI)", which integrates Earth observations, modeling, data and information, management systems and education systems. GEOSS/WCI sets up "work benches" by which partners can share data, information and applications in an interoperable way, exchange knowledge and experiences, deepen mutual understanding and work together effectively to ultimately respond to issues of both mitigation and adaptation. (A work bench is a virtual geographical or phenomenological space where experts and managers collaborate to use information to address a problem within that space). GEOSS/WCI enhances the coordination of efforts to strengthen individual, institutional and infrastructure capacities, especially for effective interdisciplinary coordination and integration. GEO has established the GEOSS Asian Water Cycle Initiative (AWCI) and GEOSS African Water Cycle Coordination Initiative (AfWCCI). Through regional, inter-disciplinary, multi-sectoral integration and inter-agency coordination in Asia and Africa, GEOSS

  9. Life Cycle Inventory Analysis

    DEFF Research Database (Denmark)

    Bjørn, Anders; Moltesen, Andreas; Laurent, Alexis

    2017-01-01

    of different sources. The output is a compiled inventory of elementary flows that is used as basis of the subsequent life cycle impact assessment phase. This chapter teaches how to carry out this task through six steps: (1) identifying processes for the LCI model of the product system; (2) planning......The inventory analysis is the third and often most time-consuming part of an LCA. The analysis is guided by the goal and scope definition, and its core activity is the collection and compilation of data on elementary flows from all processes in the studied product system(s) drawing on a combination...

  10. Elementary cycles of time

    Directory of Open Access Journals (Sweden)

    Dolce Donatello

    2013-09-01

    Full Text Available Elementary particles, i.e. the basic constituents of nature, are characterized by quantum recurrences in time. The flow of time of every physical system can be therefore decomposed in elementary cycles of time. This allows us to enforce the local nature of relativistic time, yielding interesting unified descriptions of fundamental aspects of modern physics, as shown in recent publications. Every particle can be regarded as a reference clock with time resolution of the order of the Compton time particle, many orders of magnitude more accurate than the atomic clocks. Here we report basic implications about the resulting notion of time.

  11. The software life cycle

    CERN Document Server

    Ince, Darrel

    1990-01-01

    The Software Life Cycle deals with the software lifecycle, that is, what exactly happens when software is developed. Topics covered include aspects of software engineering, structured techniques of software development, and software project management. The use of mathematics to design and develop computer systems is also discussed. This book is comprised of 20 chapters divided into four sections and begins with an overview of software engineering and software development, paying particular attention to the birth of software engineering and the introduction of formal methods of software develop

  12. Geomicrobiological cycling of antimony

    Science.gov (United States)

    Kulp, T. R.; Terry, L.; Dovick, M. A.; Braiotta, F.

    2013-12-01

    Microbiologically catalyzed oxidation and reduction of toxic metalloids (e.g., As, Se, and Te) generally proceeds much faster than corresponding abiotic reactions. These microbial transformations constitute biogeochemical cycles that control chemical speciation and environmental behavior of metalloids in aqueous environments. Particular progress has been made over the past two decades in documenting microbiological biotransformations of As, which include anaerobic respiratory reduction of As(V) to As(III), oxidation of As(III) to As(V) linked to chemoautotrophy or photoautotrophy, and cellular detoxification pathways. By contrast, microbial interactions with Sb, As's group 15 neighbor and a toxic element of emerging global concern, are poorly understood. Our work with sediment microcosms, enrichment cultures, and bacterial isolates suggests that prokaryotic metabolisms may be similarly important to environmental Sb cycling. Enrichment cultures and isolates from a Sb-contaminated mine site in Idaho exhibited Sb(V)-dependent heterotrophic respiration under anaerobic conditions and Sb(III)-dependent autotrophic growth in the presence of air. Live, anoxic cultures reduced 2 mM Sb(V) to Sb(III) within 5 d, while no activity occurred in killed controls. Sb(V) reduction was stimulated by lactate or acetate and was quantitatively coupled to the oxidation of lactate. The oxidation of radiolabeled 14C-acetate (monitored by GC-GPC) demonstrated Sb(V)-dependent oxidation to 14CO2, suggesting a dissimilatory process. Sb(V) dependent growth in cultures was demonstrated by direct counting. Microbiological reduction of Sb(V) also occurred in anerobic sediment microcosms from an uncontaminated suburban lake, but did not appear to be linked to growth and is interpreted as a mechanism of biological detoxification. Aerobic microcosms and cultures from the Idaho mine oxidized 2 mM Sb(III) to Sb(V) within 7 d and coupled this reaction to cell growth quantified by direct counting. An

  13. Kondratieff's Long-Wave Cycle.

    Science.gov (United States)

    Volland, Craig S.

    1985-01-01

    The legendary Soviet economist's classic work, "Long-Wave Cycle," has been republished. Admirers believe that it explains how the world's economy works. According to Kondratieff, the world economy follows cycles lasting from 48 to 55 years. His cycle theory is discussed. (Author/RM)

  14. Entrepreneurship and the Business Cycle

    NARCIS (Netherlands)

    Ph.D. Koellinger (Philipp); A.R. Thurik (Roy)

    2011-01-01

    textabstractWe find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972-2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment

  15. Revenue cycle management: part I.

    Science.gov (United States)

    Crew, Matt

    2006-01-01

    The revenue cycle starts long before a patient is seen and continues until a claim is completely resolved. Each step in the revenue cycle must be clearly defined and easy to follow. Use of various tools such as templates, forms, reports, spreadsheets, and components of your practice management system will help to provide the consistency you need for profitable revenue cycle management.

  16. Sometimes "Newton's Method" Always "Cycles"

    Science.gov (United States)

    Latulippe, Joe; Switkes, Jennifer

    2012-01-01

    Are there functions for which Newton's method cycles for all non-trivial initial guesses? We construct and solve a differential equation whose solution is a real-valued function that two-cycles under Newton iteration. Higher-order cycles of Newton's method iterates are explored in the complex plane using complex powers of "x." We find a class of…

  17. Political Business Cycles through Lobbying

    OpenAIRE

    Marco Bonomo; Cristina Terra

    2008-01-01

    In this paper we build a framework where the interplay between the lobby power of special interest groups and the voting power of the majority of the population leads to political business cycles. We apply our set up to explain electoral cycles in government expenditure composition as well as to cycles in aggregate expenditures and in real exchange rates.

  18. Culture in cycles: considering H.T. Odum's 'information cycle'

    Science.gov (United States)

    Abel, Thomas

    2014-01-01

    'Culture' remains a conundrum in anthropology. When recast in the mold of 'information cycles,' culture is transformed. New fault lines appear. Information is splintered into parallel or nested forms. Dynamics becomes cycling. Energy is essential. And culture has function in a directional universe. The 'information cycle' is the crowning component of H.T. Odum's theory of general systems. What follows is an application of the information cycle to the cultural domains of discourse, social media, ritual, education, journalism, technology, academia, and law, which were never attempted by Odum. In information cycles, cultural information is perpetuated - maintained against Second Law depreciation. Conclusions are that culture is in fact a nested hierarchy of cultural forms. Each scale of information production is semi-autonomous, with its own evolutionary dynamics of production and selection in an information cycle. Simultaneously, each information cycle is channeled or entrained by its larger scale of information and ultimately human-ecosystem structuring.

  19. Jumping and Hopping in Elite and Amateur Orienteering Athletes and Correlations to Sprinting and Running

    DEFF Research Database (Denmark)

    Hébert-Losier, Kim; Jensen, Kurt; Holmberg, Hans-Christer

    2014-01-01

    PURPOSE: Jumping and hopping are used to measure lower-body muscle power, stiffness, and stretch-shortening cycle utilization in sports, with several studies reporting correlations between such measures and sprinting and/or running abilities in athletes. Neither jumping and hopping nor correlations...... to road, path, and forest running and sprinting performance, as well as running economy, velocity at anaerobic threshold, and VO2peak from treadmill assessments. RESULTS: During SJs and CMJs, elites demonstrated superior relative peak forces, time-to-peak forces, and pre-stretch augmentation albeit lower......-stretch augmentation and forest running velocities. Pre-stretch augmentation and time-to-peak forces were moderately correlated to VO2peak. Correlations between running economy and jumping or hopping were small or trivial. CONCLUSIONS: Overall, our elites exhibited superior stretch-shortening cycle utilization...

  20. Nuclear Fuel Cycle; (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. (eds.)

    1991-01-01

    Nuclear Fuel Cycle (NFC) announces on a monthly basis the current worldwide information available from the open literature on all aspects of the fuel cycle except in-reactor properties and performance of fuels. More information related to radioactive waste and to the transport and storage of spent fuel is included in the current awareness publication, Radioactive Waste Management. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past month. Also included are other US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Technology Data Exchange, the International Atomic Energy Agency's International Nuclear Information System, or government-to-government agreements. The digests in NFC on nuclear fuel back to 1948 are available for online searching and retrieval in EDB and Nuclear Science Abstracts (NSA) database. Current information, added daily to EDB, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user's needs.

  1. Coming Full Cycle.

    Science.gov (United States)

    Fay, Lindsey; Carll-White, Allison; Harrell, James

    2017-04-01

    This article illustrates a collaborative, full cycle diagnostic postoccupancy evaluation (POE) conducted in an emergency department (ED) to demonstrate methods of planning a POE, conducting research to capture meaningful data, and applying outcomes through the use of a design charrette. POEs often end with the reporting of findings rather than suggesting how this knowledge feeds forward. A design charrette presents an opportunity to engage with POE evidence and integrate research into practice. Planning for the POE resulted in a multiphased, multimethodological study. Data collection and analysis utilized objective and subjective measures yielding both qualitative and quantitative data. The design charrette then served as an interactive method to assist design practitioners in both understanding and applying the research findings in the redesign of the entry/triage sequence of the ED. POE findings revealed four key issues impacting the ED experience. These include workflow, communication, privacy and confidentiality, and safety and security. In analyzing the use of the charrette to link POE findings to design application, it was determined that the charrette should include an all-inclusive, collaborative process, easily interpreted evidence, active participant engagement, and feasible outcomes grounded in research. Taking the POE process full cycle is a critical component in bridging the gap between research and its application to design. The charrette process offers a positive mark of completion to the POE and helps participants gain sensitivity to the importance of evidence-based decision-making.

  2. Frozen embryo transfer can be performed in the cycle immediately following the freeze-all cycle.

    Science.gov (United States)

    Ozgur, Kemal; Bulut, Hasan; Berkkanoglu, Murat; Humaidan, Peter; Coetzee, Kevin

    2018-01-01

    In this study, we investigated whether the time interval between oocyte retrieval and frozen embryo transfer (FET) affected the live birth (LB) rates of human segmented-IVF cycles. A total of 1338 ICSI freeze-all cycles were performed between February 2015 and January 2016, with 1121 FET cycles being retrospectively analyzed. All vitrified-warmed blastocyst transfers were performed in artificial FET cycles, using gonadotropin-releasing hormone (GnRH) agonist downregulation and oral estrogen endometrial preparation. The primary outcome measure was LB. Cycles were investigated in oocyte retrieval-to-FET interval groups of 32-46, 47-61, 62-76, 77-91, and ≥ 92 days, with the 47-61-day group used as the reference group. There were no significant differences in LB rates between the groups in the overall analysis, as well as, in sub-analyses investigating LB in terms of single blastocyst transfer (SBT), trigger type (GnRH agonist, triggers including hCG), oocyte number (≤ 5 and ≥ 15), and maternal age (> 35 years). The present study showed that it is feasible to perform transfers 36 days after oocyte retrieval and that delaying FET in freeze-all beyond the cycle immediately following oocyte retrieval does not increase LB rates.

  3. Assessing the impact of road traffic on cycling for leisure and cycling to work

    Directory of Open Access Journals (Sweden)

    Wareham Nicholas J

    2011-06-01

    Full Text Available Abstract Background To explore the relationship between leisure and commuter cycling with objectively measured levels of road traffic and whether any relationship was affected by traffic levels directly outside of home or in local neighbourhood. Findings We conducted a secondary analysis of data from the UK European Prospective Investigation of Cancer (EPIC Norfolk cohort in 2009. We used a geographical information system (GIS and gender specific multivariate models to relate 13 927 participants' reported levels of cycling with an index of road traffic volume (Road Traffic Volume Index Score - RTVIS. RTVIS were calculated around each participants home, using four distance based buffers, (0.5 km, 1 km, 2 km and 3.2 km. Models were adjusted for age, social status, education, car access and deprivation. Both genders had similar decreases in leisure cycling as traffic volumes increased at greater distances from home (OR 0.42, (95% CI 0.32-0.52, p Conclusions Traffic volumes appear to have greater impact on leisure cycling than commuter cycling. Future research should investigate the importance of traffic on different types of cycling and include psychosocial correlates.

  4. Skin Aging

    Science.gov (United States)

    ... too. Sunlight is a major cause of skin aging. You can protect yourself by staying out of ... person has smoked. Many products claim to revitalize aging skin or reduce wrinkles, but the Food and ...

  5. Influence of menstrual cycle on cardiac performance.

    Science.gov (United States)

    Zengin, Kadriye; Tokac, Mehmet; Duzenli, Mehmet Akif; Soylu, Ahmet; Aygul, Nazif; Ozdemir, Kurtulus

    2007-09-20

    The purpose of this study was to investigate the relationship between endogen sex hormone levels and myocardial performance in two different phases of menstrual cycle. The relationships between cardiac performance and sex hormone levels in menstrual cycle have not yet been clearly identified. Twenty-seven women at the age of 19-42 years (mean 24.11+/-6.02) with regular menstrual cycles (28-31 days) were enrolled in this study. Cardiac performance was evaluated by tissue Doppler imaging (TDI) derived myocardial performance index (MPI) in the menstrual and the luteal phases of the menstrual cycle. Left ventricular MPI were statistically significant between the menstrual phase and luteal phase of the menstrual cycle (Inferior 0.53+/-0.10 versus 0.44+/-0.09, P<0.001; Anterior 0.54+/-0.13 versus 0.45+/-0.10, P<0.008; Lateral 0.50+/-0.09 versus 0.44+/-0.12, P<0.03; Septum 0.54+/-0.07 versus 0.46+/-0.10, P<0.005; Global 0.52+/-0.06 versus 0.44+/-0.09, P<0.001). Right ventricle MPI between the two periods was also significantly different (0.49+/-0.10 versus 0.42+/-0.10, P<0.01). There was a moderate correlation between estrogen levels and global MPI (r=0.46, P=0.001), but no correlation was found between progesterone levels and global MPI (r=0.22, P=NS). We firstly demonstrated that endogen estrogen or progesterone improved the combined systolic and diastolic function in both left and right ventricle during luteal phases of menstrual cycle. Considering the previous studies and our results, estrogen may be responsible for this improvement.

  6. OVARIAN AGING AND INFERTILITY TREATMENT

    Directory of Open Access Journals (Sweden)

    Helena Meden Vrtovec

    2003-12-01

    Full Text Available Background. Due to changes in the socio-economic environment the first pregnancy is being more often postponed to advanced age; an increasing number of women seek medical help for infertility in their late thirties. Degenerative processes in the ovary start as early as after 35 years of age. When the woman is over 38, the signs of hormonal changes occur (FSH, inhibin, the menstrual cycle changes, and fertility is being increasingly reduced. Infertility treatment by assisted reproduction technology (ART has proved less efficient in older than in younger women.Material and methods. In a retrospective analysis we evaluated the success rates achieved with homologous intrauterine insemination (IUI, in vitro fertilization and embryo-transfer (IVF-ET, intracytoplasmic sperm injection (ICSI, and compared them in regard to the women > 38 years vs. < 38 years.Results. After IUI the pregnancy rate in the women over 38 was 3.7% per patient (1.5% per cycle and 28.0% (9.9% in the women younger than 38 years. After IVF-ET the pregnancy rate in the over 38-year group was 16% per patient (14% per cycle, and 28% per patient (25% per cycle in the less than 38-year group. After ICSI, the pregnancy rate in the group over 38 years was 11% per patient (9% per cycle, and 25% per patient (22% per cycle in the less than 38-year group. In the analysed population, the spontaneous abortion rate was 26.0% in the group of women aged over 38 years, and 14.0% in the group of women aged less than 38 years.Conclusions. Before introduction of an ART procedure the woman with advanced age should be properly counselled and well informed about poor success of their infertility treatment and high spontaneous abortion rate.

  7. LIFE CYCLE OF INFORMATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Y. S. Sennik

    2015-01-01

    Full Text Available This work is a generalization of the theoretical propositions related to the life cycle of information systems. There was given the definition of the life cycle, specify which items you should include every step of the cycle. Describes the methodology division of the life cycle on the main stage, including methodology Rational Unified Process. The description of the fundamental standards in this area. Special attention was paid to the work of the basic life cycle models. It was carried out their comparative characteristics. On the basis of the theoretical propositions, it was concluded that the preferred model of the life cycle for the corporate network is a spiral model and the use of international standards in the life cycle saves a lot of effort, time and material resources.

  8. Impact of entrainment and impingement on fish populations in the Hudson River Estuary. Volume II. Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass spawning stock, and the LMS real-time life cycle model

    Energy Technology Data Exchange (ETDEWEB)

    Barnthouse, L. W.; Van Winkle, W.; Golumbek, J.; Cada, G. F.; Goodyear, C. P.; Christensen, S. W.; Cannon, J. B.; Lee, D. W.

    1982-04-01

    This volume includes a series of four exhibits relating to impacts of impingement on fish populations, together with a collection of critical evaluations of testimony prepared for the utilities by their consultants. The first exhibit is a quantitative evaluation of four sources of bias (collection efficiency, reimpingement, impingement on inoperative screens, and impingement survival) affecting estimates of the number of fish killed at Hudson River power plants. The two following exhibits contain, respectively, a detailed assessment of the impact of impingement on the Hudson River white perch population and estimates of conditional impingement mortality rates for seven Hudson River fish populations. The fourth exhibit is an evaluation of the engineering feasibility and potential biological effectiveness of several types of modified intake structures proposed as alternatives to cooling towers for reducing impingement impacts. The remainder of Volume II consists of critical evaluations of the utilities' empirical evidence for the existence of density-dependent growth in young-of-the-year striped bass and white perch, of their estimate of the age-composition of the striped bass spawning stock in the Hudson River, and of their use of the Lawler, Matusky, and Skelly (LMS) Real-Time Life Cycle Model to estimate the impact of entrainment and impingement on the Hudson River striped bass population.

  9. Krebs Cycle Wordsearch

    Science.gov (United States)

    Helser, Terry L.

    2001-04-01

    This puzzle embeds 46 names, terms, abbreviations, and acronyms about the citric acid (Krebs) cycle in a 14- x 17-letter matrix. A descriptive narrative beside it describes important features of the pathway. All the terms a student needs to find are embedded there with the first letter followed by underlined blanks to be completed. Therefore, the students usually must find the terms to know how to spell them, correctly fill in the blanks in the narrative with the terms, and then find and highlight the terms in the letter matrix. When all are found, the 24 unused letters complete a sentence that describes a major feature of this central pathway. The puzzle may be used as homework, an extra-credit project, or a group project in the classroom in any course where basic metabolism is learned. It disguises as fun the hard work needed to learn the names of the intermediates, enzymes, and cofactors.

  10. Open cycle thermoacoustics

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Robert Stowers [Georgia Inst. of Technology, Atlanta, GA (United States)

    2000-01-01

    A new type of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process is discussed and experimentally demonstrated. The gas flowing through this device can be heated or cooled in a series of semi-open cyclic steps. The combination of open and cyclic flows makes possible the elimination of some or all of the heat exchangers (with their associated irreversibility). Heat is directly exchanged with the process fluid as it flows through the device when operating as a refrigerator, producing a staging effect that tends to increase First Law thermodynamic efficiency. An open-flow thermoacoustic refrigerator was built to demonstrate this concept. Several approaches are presented that describe the physical characteristics of this device. Tests have been conducted on this refrigerator with good agreement with a proposed theory.

  11. Variable cycle engine

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, A.P.; Sprunger, E.V.

    1980-09-16

    A variable cycle turboshaft engine includes a remote fan system and respective high and low pressure systems for selectively driving the fan system in such a manner as to provide VTOL takeoff capability and minimum specific fuel consumption (SFC) at cruise and loiter conditions. For takeoff the fan system is primarily driven by the relatively large low pressure system whose combustor receives the motive fluid from a core bypass duct and, for cruise and loiter conditions, the fan system is driven by both a relatively small high pressure core and the low pressure system with its combustor inoperative. A mixer is disposed downstream of the high pressure system for mixing the relatively cold air from the bypass duct and the relatively hot air from the core prior to its flow to the low pressure turbine.

  12. Longitudinal study of insulin resistance and sex hormones over the menstrual cycle: the BioCycle Study.

    Science.gov (United States)

    Yeung, Edwina H; Zhang, Cuilin; Mumford, Sunni L; Ye, Aijun; Trevisan, Maurizio; Chen, Liwei; Browne, Richard W; Wactawski-Wende, Jean; Schisterman, Enrique F

    2010-12-01

    Conflicting findings have been reported regarding the effect of menstrual cycle phase and sex hormones on insulin sensitivity. The aim was to determine the pattern of insulin resistance over the menstrual cycle and whether variations in sex hormones explain these patterns. The BioCycle study is a longitudinal study that measured hormones at different phases of the menstrual cycle. Participants had up to eight visits per cycle; each visit was timed using fertility monitors to capture sensitive windows of hormonal changes. The study was conducted in the general community of the University at Buffalo (Buffalo, NY). A total of 257 healthy, premenopausal women (age, 27±8 yr; body mass index, 24±4 kg/m2) participated in the study. We measured fasting insulin, glucose, and insulin resistance by the homeostasis model of insulin resistance (HOMA-IR). Significant changes in HOMA-IR were observed over the menstrual cycle; from a midfollicular phase level of 1.35, levels rose to 1.59 during the early luteal phase and decreased to 1.55 in the late-luteal phase. HOMA-IR levels primarily reflected changes in insulin and not glucose. After adjustment for age, race, cycle, and other sex hormones, HOMA-IR was positively associated with estradiol (β=0.082; Pmenstrual cycle variability. Estradiol and progesterone were positively associated with insulin resistance and should be considered in studies of insulin resistance among premenopausal women.

  13. Anoxygenic Photosynthesis Modulated Proterozoic Oxygen and Sustained Earth's Middle Age

    National Research Council Canada - National Science Library

    D. T. Johnston; F. Wolfe-Simon; A. Pearson; A. H. Knoll

    2009-01-01

    ... (including physiologically versatile cyanobacteria) influenced biogeochemical cycling during Earth's middle age, helping to perpetuate our planet's intermediate redox state by tempering O₂ production...

  14. Sleep quality and the menstrual cycle.

    Science.gov (United States)

    Romans, Sarah E; Kreindler, David; Einstein, Gillian; Laredo, Sheila; Petrovic, Michele J; Stanley, James

    2015-04-01

    This study aimed to assess the temporal relationship of subjective sleep quality to menstrual cycle phase in a community (non help-seeking) sample of adult women over six months. Previous work has produced contradictory results and often used student samples. This was a cohort study, using daily electronic data collection in the Greater Toronto Area, Ontario, Canada; 76 women aged 18-42 years recruited by random digit telephone dialing, recorded mood, sleep quality, and other health variables on a daily basis for 24 weeks. Using linear mixed models, we assessed the relationship between subjective sleep quality and three menstrual cycle phases (menses, premenstrual and midcycle) over 395 cycles. Premenstrual sleep quality was poorer than during the rest of the cycle, with a mean difference of 1.32 between premenstrual and midcycle reference phase, on a 1-100 quality scale (higher score denotes poorer quality). This difference held when the independent variables of daily exercise and physical health were added to the model; it became non-significant when perceived stress and later, social support were also added to the model. Sleep quality in adult non-help seeking women is statistically poorer in the premenstruum but the size of the difference is of little clinical significance and was no longer statistically significant with inclusion of the potentially confounding variables, perceived stress and social support. Copyright © 2014. Published by Elsevier B.V.

  15. Cycling and bone health: a systematic review

    Directory of Open Access Journals (Sweden)

    Olmedillas Hugo

    2012-12-01

    Full Text Available Abstract Background Cycling is considered to be a highly beneficial sport for significantly enhancing cardiovascular fitness in individuals, yet studies show little or no corresponding improvements in bone mass. Methods A scientific literature search on studies discussing bone mass and bone metabolism in cyclists was performed to collect all relevant published material up to April 2012. Descriptive, cross-sectional, longitudinal and interventional studies were all reviewed. Inclusion criteria were met by 31 studies. Results Heterogeneous studies in terms of gender, age, data source, group of comparison, cycling level or modality practiced among others factors showed minor but important differences in results. Despite some controversial results, it has been observed that adult road cyclists participating in regular training have low bone mineral density in key regions (for example, lumbar spine. Conversely, other types of cycling (such as mountain biking, or combination with other sports could reduce this unsafe effect. These results cannot yet be explained by differences in dietary patterns or endocrine factors. Conclusions From our comprehensive survey of the current available literature it can be concluded that road cycling does not appear to confer any significant osteogenic benefit. The cause of this may be related to spending long hours in a weight-supported position on the bike in combination with the necessary enforced recovery time that involves a large amount of time sitting or lying supine, especially at the competitive level.

  16. Successful ageing

    DEFF Research Database (Denmark)

    Kusumastuti, Sasmita; Derks, Marloes G. M.; Tellier, Siri

    2016-01-01

    on the objective measurements as determined by researchers. Subsequent sub-clustering analysis pointed to different domains of functioning and various ways of assessment. CONCLUSION: In the current literature two mutually exclusive concepts of successful ageing are circulating that depend on whether the individual......BACKGROUND: Ageing is accompanied by an increased risk of disease and a loss of functioning on several bodily and mental domains and some argue that maintaining health and functioning is essential for a successful old age. Paradoxically, studies have shown that overall wellbeing follows...... a curvilinear pattern with the lowest point at middle age but increases thereafter up to very old age. OBJECTIVE: To shed further light on this paradox, we reviewed the existing literature on how scholars define successful ageing and how they weigh the contribution of health and functioning to define success...

  17. Removing Cycles in Esterel Programs

    Directory of Open Access Journals (Sweden)

    Reinhard von Hanxleden

    2007-05-01

    Full Text Available Esterel belongs to the family of synchronous programming languages, which are affected by cyclic signal dependencies. This prohibits a static scheduling, limiting the choice of available compilation techniques for programs with such cycles. This work proposes an algorithm that, given a constructive synchronous Esterel program, performs a semantics-preserving source code level transformation that removes cyclic signal dependencies. The transformation is divided into two parts: detection of cycles and iterative resolution of these cycles. It is based on the replacement of cycle signals by a signal expression involving no other cycle signals, thereby breaking the cycle. This transformation of cyclic Esterel programs enables the use of efficient compilation techniques, which are only available for acyclic programs. Furthermore, experiments indicate that the code transformation can even improve code quality produced by compilers that can already handle cyclic programs.

  18. The Global Nitrogen Cycle

    Science.gov (United States)

    Galloway, J. N.

    2003-12-01

    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  19. Menstrual cycle disorders in female volleyball players.

    Science.gov (United States)

    Wodarska, M; Witkoś, J; Drosdzol-Cop, A; Dąbrowska, J; Dąbrowska-Galas, M; Hartman, M; Plinta, R; Skrzypulec-Plinta, V

    2013-07-01

    The aim of this study was to examine the relation between increased physical activity and menstrual disorders in adolescent female volleyball players. The study was conducted on 210 Polish female volleyball players, aged 13-17 years, the authorship questionnaire was used. The results of the study showed that irregular menstruation occurred in 19% of girls, spotting between menstrual periods in 27% and heavy menstruation was reported in 33% of girls. Out of all volleyball female players participating in the study, 94 girls (45%) declared absence of menstrual periods after regular cycles. Statistical analysis showed that the more training hours per week, the bigger probability of the occurrence of irregular menstruation. It was concluded that the number of hours of volleyball training per week affects regularity of menstrual cycles in female volleyball players. The absence of menstruation might be caused by the duration of training per week or years of training.

  20. Life cycle of transformer oil

    Directory of Open Access Journals (Sweden)

    Đurđević Ksenija R.

    2008-01-01

    Full Text Available The consumption of electric power is constantly increasing due to industrialization and population growth. This results in much more severe operating conditions of transformers, the most important electrical devices that make integral parts of power transmission and distribution systems. The designed operating life of the majority of worldwide transformers has already expired, which puts the increase of transformer reliability and operating life extension in the spotlight. Transformer oil plays a very important role in transformer operation, since it provides insulation and cooling, helps extinguishing sparks and dissolves gases formed during oil degradation. In addition to this, it also dissolves moisture and gases from cellulose insulation and atmosphere it is exposed to. Further and by no means less important functions of transformer are of diagnostic purpose. It has been determined that examination and inspection of insulation oil provide 70% of information on transformer condition, which can be divided in three main groups: dielectric condition, aged transformer condition and oil degradation condition. By inspecting and examining the application oil it is possible to determine the condition of insulation, oil and solid insulation (paper, as well as irregularities in transformer operation. All of the above-mentioned reasons and facts create ground for the subject of this research covering two stages of transformer oil life cycle: (1 proactive maintenance and monitoring of transformer oils in the course of utilization with reference to influence of transformer oil condition on paper insulation condition, as well as the condition of the transformer itself; (2 regeneration of transformer oils for the purpose of extension of utilization period and paper insulation revitalization potential by means of oil purification. The study highlights advantages of oil-paper insulation revitalization over oil replacement. Besides economic, there are

  1. Biomass Gasification Combined Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Judith A. Kieffer

    2000-07-01

    Gasification combined cycle continues to represent an important defining technology area for the forest products industry. The ''Forest Products Gasification Initiative'', organized under the Industry's Agenda 2020 technology vision and supported by the DOE ''Industries of the Future'' program, is well positioned to guide these technologies to commercial success within a five-to ten-year timeframe given supportive federal budgets and public policy. Commercial success will result in significant environmental and renewable energy goals that are shared by the Industry and the Nation. The Battelle/FERCO LIVG technology, which is the technology of choice for the application reported here, remains of high interest due to characteristics that make it well suited for integration with the infrastructure of a pulp production facility. The capital cost, operating economics and long-term demonstration of this technology area key input to future economically sustainable projects and must be verified by the 200 BDT/day demonstration facility currently operating in Burlington, Vermont. The New Bern application that was the initial objective of this project is not currently economically viable and will not be implemented at this time due to several changes at and around the mill which have occurred since the inception of the project in 1995. The analysis shows that for this technology, and likely other gasification technologies as well, the first few installations will require unique circumstances, or supportive public policies, or both to attract host sites and investors.

  2. The nitrogen cycle.

    Science.gov (United States)

    Stein, Lisa Y; Klotz, Martin G

    2016-02-08

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The earth's hydrological cycle

    CERN Document Server

    Bonnet, R-M; Calisto, M; Destouni, G; Gurney, R; Johannessen, J; Kerr, Y; Lahoz, WA; Rast, M

    2014-01-01

    This book gives a comprehensive presentation of our present understanding of the Earth's Hydrological cycle and the problems, consequences and impacts that go with this topic. Water is a central component in the Earth's system. It is indispensable for life on Earth in its present form and influences virtually every aspect of our planet's life support system. On relatively short time scales, atmospheric water vapor interacts with the atmospheric circulation and is crucial in forming the Earth's climate zones. Water vapor is the most powerful of the greenhouse gases and serves to enhance the tropospheric temperature. The dominant part of available water on Earth resides in the oceans. Parts are locked up in the land ice on Greenland and Antarctica and a smaller part is estimated to exist as groundwater. If all the ice over the land and all the glaciers were to melt, the sea level would rise by some 80 m. In comparison, the total amount of water vapor in the atmosphere is small; it amounts to ~ 25 kg/m2, or the ...

  4. Specific cell cycle synchronization with butyrate and cell cycle analysis

    Science.gov (United States)

    Synchronized cells have been invaluable for many kinds of cell cycle and cell proliferation studies. Butyrate induces cell cycle arrest and apoptosis in MDBK cells. To explore the possibility of using butyrate-blocked cells to obtain synchronized cells, we investigated the property of the cell cyc...

  5. Safety effects of the London cycle superhighways on cycle collisions.

    Science.gov (United States)

    Li, Haojie; Graham, Daniel J; Liu, Pan

    2017-02-01

    This paper evaluates the effects of the London Cycle Superhighways (CS) on cycle collisions. A total of 45 CS segments and 375 control segments are observed for a period of 8 years in London. Variables such as road characteristics, crash history and socio-economic information are included in the data set. Traffic characteristics including traffic volume, cycle volume and traffic speed are obtained from Department for Transport. We first estimate the safety effects on the CS routes using Empirical Bayes methods. Then propensity score matching methods are also applied for comparison. The introduction of cycle superhighways caused cycling traffic volumes to increase dramatically along CS routes with no significant impacts on collision rates. Our models find that the increase in traffic was associated with a rise in annual total cycle collisions of around 2.6 per km (38% in percentage). However, when we re-estimate the effects based on cycle collision rates rather than levels, our results also show that the CS routes are not more dangerous or safer than the control roads. Among the four CS routes, CS3 performs the best in protecting cyclists with a large proportion of segregated lanes whilst the cyclists have to share the lanes with motorists on other routes. It is recommended that consistent safety designs should be applied on all CS routes for a safer cycling environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 'Benefits cycle' replacing premium cycle as consumerism takes hold.

    Science.gov (United States)

    2002-05-01

    The traditional premium cycle of ups and downs in rates is giving way to a new phenomenon--driven by the advent of consumerism in health care--termed the "benefits cycle" by one consultant. Rather than shifts in rates, he argues, the future will see shifts in benefits packages.

  7. Serializing Age

    DEFF Research Database (Denmark)

    resulted in complex television narratives, in which experimental temporalities and revisions of narrative linearity and chronological time have become key features. As the first of its kind, this volume investigates how TV series as a powerful cultural medium shape representations of age and aging...

  8. Successful Aging

    Directory of Open Access Journals (Sweden)

    Taufiqurrahman Nasihun

    2015-06-01

    Full Text Available The emerging concept of successful aging is based on evidence that in healthy individual when they get aged, there are  considerable variations in physiological functions alteration. Some people exhibiting greater, but others very few or no age related alteration. The first is called poor aging and the later is called successful pattern of aging (Lambert SW, 2008. Thus, in the simple words the successful aging concept is define as an opportunity of old people to stay  active and productive condition despite they get aged chronologically. Aging itself might be defined as the progressive accumulation of changes with time associated with or responsible for the ever-increasing susceptibility to disease and death which accompanies advancing age (Harman D, 1981. The time needed to accumulate changes is attributable to aging process. The marked emerging questions are how does aging happen and where does aging start? To answer these questions and because of the complexity of aging process, there are more than 300 aging theories have been proposed to explain how and where aging occured and started respectively. There are too many to enumerate theories and classification of aging process. In summary, all of these aging theories can be grouped into three clusters: 1. Genetics program theory, this theory suggests that aging is resulted from program directed by the genes; 2. Epigenetic theory, in these theory aging is resulted from environmental random events not determined by the genes; 3. Evolutionary theory, which propose that aging is a medium for disposal mortal soma in order to avoid competition between organism and their progeny for food and space, did not try to explain how aging occur, but possibly answer why aging occur (De la Fuente. 2009. Among the three groups of aging theories, the epigenetic theory is useful to explain and try to solve the enigma of aging which is prominently caused by internal and external environmental influences

  9. Economic growth and business cycles

    NARCIS (Netherlands)

    Canton, E.J.F.

    1997-01-01

    This thesis contains five essays on economic growth and business cycles. The main focus is on the interaction between economic growth and the cycle: is cyclical variability good or bad for the long-run rate of economic growth? The introduction aims to provide some empirical evidence for an

  10. Credit cycles and macro fundamentals

    NARCIS (Netherlands)

    Koopman, S.J.; Kraeussl, R.G.W.; Lucas, A.; Monteiro, A.

    2009-01-01

    We use an intensity-based framework to study the relation between macroeconomic fundamentals and cycles in defaults and rating activity. Using Standard and Poor's U.S. corporate rating transition and default data over the period 1980-2005, we directly estimate the default and rating cycle from micro

  11. The LifeCycle model

    DEFF Research Database (Denmark)

    Krink, Thiemo; Løvbjerg, Morten

    2002-01-01

    Adaptive search heuristics are known to be valuable in approximating solutions to hard search problems. However, these techniques are problem dependent. Inspired by the idea of life cycle stages found in nature, we introduce a hybrid approach called the LifeCycle model that simultaneously applies...

  12. Emissions from photovoltaic life cycles

    NARCIS (Netherlands)

    Fthenakis, V.M.; Kim, H.C.; Alsema, E.A.|info:eu-repo/dai/nl/073416258

    2008-01-01

    Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004–2006, this study presents the life-cycle

  13. Hamiltonian cycles in polyhedral maps

    Indian Academy of Sciences (India)

    We present a necessary and sufficient condition for existence of a contractible, non-separating and non-contractible separating Hamiltonian cycle in the edge graph of polyhedral maps on surfaces.We also present algorithms to construct such cycles whenever it exists where one of them is linear time and another is ...

  14. Reducing Life-Cycle Costs.

    Science.gov (United States)

    Roodvoets, David L.

    2003-01-01

    Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

  15. Menstrual cycle and skin reactivity

    DEFF Research Database (Denmark)

    Agner, T; Damm, P; Skouby, S O

    1991-01-01

    The hypothesis was tested that a cyclic variation exists in skin reactivity to irritant stimuli. Twenty-nine healthy women with regular menstrual cycles were challenged with sodium lauryl sulfate as an irritant patch test at day 1 and at days 9 through 11 of the menstrual cycle. The skin response...

  16. Cycling, modernity and national culture.

    NARCIS (Netherlands)

    Oosterhuis, Harry

    2016-01-01

    This historiographical essay provides an overview of extensive recent work on the history of cycling to show the diverse ways in which the bicycle was adopted and experienced across Western societies. Two key aspects are explored. Firstly, it discusses the complex relationship between cycling and

  17. Oil Origin and Age

    Directory of Open Access Journals (Sweden)

    A.A. Barenbaum

    2017-03-01

    Full Text Available The question of oil age is discussed on the basis of the biosphere concept of oil and gas formation. It considers oil and gas deposits as underground carbon traps circulating through the Earth’s surface in the three main cycles of the circulation. A theoretical model has been developed that makes it possible to explain from these positions the phenomenon of replenishment of oil and gas deposits in the process of field development. The model provides a balance between carbon flows on the ascending and descending branches of its circulation through the Earth’s surface. In this model, the ascending flow of carbon is represented by the products of subsoil degassing (СН4, СО2 and extracted by the person from the depths of oil, gas and coal. A descending flow is an organic matter and carbonates that are submerged in the subsoil in the processes of sedimentation and subduction of lithospheric plates, as well as atmospheric COsub>2, entering the Earth’s surface with meteoric waters in the process of their climatic circulation. Since the fields are filled with hydrocarbons formed in cycles of carbon with widely differing circulation times, instead of the term ‘age of oil’, it is suggested to use the terms ‘trap formation time’ and ‘hydrocarbon life time in the trap’. This approach to the question of oil age in the biosphere concept leads to a number of conclusions, from which it follows that: 1 the ‘old’ petroleum of biogenic genesis is extracted at the initial stage of the development of deposits, whereas in the depletion stage the ‘young’ hydrocarbons of abiogenic synthesis prevail; 2 the age of industrial accumulations of oil on our planet is hardly older than the Pleistocene, while gaseous, liquid and bituminous fractions of oil have different lifetimes in traps.

  18. Healthy Ageing

    NARCIS (Netherlands)

    Dr. C.P. van der Schans

    2015-01-01

    Presentatie gehouden bij de bijeenkomst voor het Regionaal Genootschap Fysiotherapie Het Noorden op 10 februari te Marum, over het belang van fysieke activiteit voor healthy ageing en de rol van de fysiotherapeut hierin

  19. Limit cycles in quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Patrick

    2015-04-27

    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  20. Understanding aging.

    Science.gov (United States)

    Strehler, B L

    2000-01-01

    Enormous advances in our understanding of human aging have occurred during the last 50 yr. From the late 19th to the mid-20th centuries only four comprehensive and important sources of information were available: 1. August Weismann's book entitled Essays on Heredity and Kindred Biological Problems (the first of these essays dealt with The Duration of Life; 1). Weissmann states (p. 10) "In the first place in regulating the length of life, the advantage to the species, and not to the individual, is alone of any importance. This must be obvious to any one who has once thoroughly thought out the process of natural selection_". 2. A highly systematized second early source of information on aging was the collection of essays edited by Cowdry and published in 1938. This 900+ page volume contains 34 chapters and was appropriately called Problems of Aging. 3. At about the same time Raymond Pearl published his book on aging (2). Pearl believed that aging was the indirect result of cell specialization and that only the germ line was resistant to aging. Unfortunately Pearl died in the late 1930s and is largely remembered now for having been the founding editor of Quarterly Review of Biology while he was at the Johns Hopkins University, this author's alma mater. 4. Alexis Carrel wrote a monumental scientific and philosophical book, Man, the Unknown (3). Carrel believed that he had demonstrated that vertebrate cells could be kept in culture and live indefinitely, a conclusion challenged by others (more on this later).

  1. Overview of cycling injuries: results of a cycling club survey.

    Science.gov (United States)

    Decalzi, Javier F; Narvy, Steven J; Vangsness, C Thomas

    2013-04-01

    Participation in competitive bicycling has increased substantially over the past decade, and bicycle injuries have increased accordingly. Cycling has been reported in several studies to have higher rates of injury than other sports and recreational activities; accordingly, riders must be cognizant of the potential for injury and protect themselves appropriately. The purpose of the current study was to survey an established competitive Los Angeles-based road cycling team to determine the epidemiology of and circumstances for traumatic cycling injuries. Copyright 2013, SLACK Incorporated.

  2. Cycling infrastructure for reducing cycling injuries in cyclists

    OpenAIRE

    Mulvaney, C.; Smith, S.; Watson, M; Parkin, J.; Coupland, C; Miller, P; Kendrick, D.; McClintock, H.

    2015-01-01

    Background\\ud Cycling is an attractive form of transport. It is beneficial to the individual as a form of physical activity that may fit more readily into an individual’s daily routine, such as for cycling to work and to the shops, than other physical activities such as visiting a gym. Cycling is also beneficial to the wider community and the environment as a result of fewer motorised journeys. Cyclists are seen as vulnerable road users who are frequently in close proximity to larger and fast...

  3. Postwar fertility cycles and the Easterlin hypothesis: a life-cycle approach.

    Science.gov (United States)

    Moffitt, R A

    1982-01-01

    The Easterlin hypothesis is discussed in the context of the life-cycle model. Fertility rates rose by 15% after World War II, and have fallen steadily since. The Easterlin hypothesis states that such a pattern could be generated if each generation makes its fertility decisions based on its own income relative to the income of its parental generation. The income of one generation determines the level of material well-being to which its children become accustomed; when the children grow up they will desire material goods rather than children in order to retain the lifestyle they are accustomed to. In the traditional statement of the hypothesis, relative income is defined as some ratio of the current incomes of 2 generations at particular points in time; from the viewpoint of the life-cycle theory, the concept of the income of a cohort is replaced by the concept of lifetime wealth, the value of the income received over the entire life cycle. In this article, a value of lifetime wealth is constructed for each of the cohorts of childbearing age in the postwar period and for each of their parental cohorts. Regression analysis is employed to determine whether the lifetime wealth of a cohorts' parents significantly affects its fertility. Parental wealth has a strong negative effect on a cohort's age-specific fertility rate and own-cohort wealth is found to have a positive effect on fertility rates. This article contains a discussion of the life-cycle model, explains the regression equation, presents the method used to estimate lifetime wealth and fertility regressions, and provides an examination of the effect of own and parental wealth on a cohort's pattern of female labor force participation. There appear to be underlying trends in fertility rates that are independent of relative wealth, but this article demonstrates that the Easterlin hypothesis provides at least a strong partial explanation for postwar fertility cycles.

  4. Variations on the Zilch Cycle

    Science.gov (United States)

    Binder, P.-M.; Tanoue, C. K. S.

    2013-10-01

    Thermo dynamic cycles in introductory physics courses are usually made up from a small number of permutations of isothermal, adiabatic, and constant-pressure and volume quasistatic strokes, with the working fluid usually being an ideal gas. Among them we find the Carnot, Stirling, Otto, Diesel, and Joule-Brayton cycles; in more advanced courses, steam cycles and refrigerators based on real working fluids are often introduced. Any additional cycles made up from the same simple strokes, and any extended analysis of known cycles, are welcome additions to the teaching repertory, as they provide more opportunities for practice and discussion. Our purpose in this note is to extend the analysis of the zilch cycle, introduced in Ref. 1, by presenting its TS diagram and by proposing several variations that do not contain adiabatic strokes, thus allowing a simpler mathematical treatment. As a bonus, we also provide results that make it possible to represent practically any elementary ideal-gas cycle in a TS diagram.

  5. Tram system related cycling injuries.

    Science.gov (United States)

    Maempel, J F; Mackenzie, S P; Stirling, P H C; McCann, C; Oliver, C W; White, T O

    2018-01-24

    Understanding of tram-system related cycling injuries (TSRCI) is poor. The aim of this study was to report the spectrum of injuries, demographics and social deprivation status of patients. Secondary aims included assessment of accident circumstances, effects of TSRCI on patients' confidence cycling, together with time off work and cycling. A retrospective review of patients presenting to emergency services across all hospitals in Edinburgh and West Lothian with tram related injuries between May 2009 and April 2016 was undertaken. Medical records and imagining were analysed and patients were contacted by telephone. 191 cyclists (119 males, 72 females) were identified. 63 patients sustained one or more fractures or dislocations. Upper limb fractures/dislocations occurred in 55, lower limb fractures in 8 and facial fractures in 2. Most patients demonstrated low levels of socioeconomic deprivation. In 142 cases, the wheel was caught in tram-tracks, while in 32 it slid on tracks. The latter occurred more commonly in wet conditions (p = 0.028). 151 patients answered detailed questionnaires. Ninety-eight were commuting. 112 patients intended to cross tramlines and 65 accidents occurred at a junction. Eighty patients reported traffic pressures contributed to their accident. 120 stated that their confidence was affected and 24 did not resume cycling. Female gender (p cycling (median 57 days vs 21, p cycling. TSRCI can result in significant loss of working and cycling days.

  6. Holocene carbon cycle dynamics: HOLOCENE CARBON CYCLE DYNAMICS

    National Research Council Canada - National Science Library

    Kleinen, Thomas; Brovkin, Victor; von Bloh, Werner; Archer, David; Munhoven, Guy

    2010-01-01

    .... Apart from the deep sea sediments, important carbon cycle processes considered are carbon uptake or release by the vegetation, carbon uptake by peatlands, and CO2 release due to shallow water sedimentation of CaCO3...

  7. Exercises for Development of Cycling Technique on Cycling Indoor Track

    OpenAIRE

    Petr, Lukáš

    2006-01-01

    Exercises Enhancing the track cycling technique Aim: The aim of this thesis is to compile and verify in practice exercises for inventory development and training proper techniques bike ride along the bike path. These exercises should be included in the beginning and during the cycling training. In conclusion, the thesis is whether Applications should exercise for the development of proper riding techniques on the bike path positive impact on the group of competitors, or if they had no effect....

  8. Corporate governance cycles during transition

    DEFF Research Database (Denmark)

    Mygind, Niels; Demina, Natalia; Gregoric, Aleksandra

    2004-01-01

    Ownership is determined by firm specific factors and the environment. Firms change over their life-cycle. The governance cycle - here defined as changes in identity of the dominant owner and own-ership concentration - is marked by key phases including start-up, growth, and possibly a restructur......-ing or exit stage. During transition the cycle reflects: privatization often with a high proportion of employee ownership like in Russia and in Slovenia; strong pressures for restructuring and owner-ship changes; limited possibility for external finance because of embryonic development of the fi...

  9. Corporate governance cycles during transition

    DEFF Research Database (Denmark)

    Jones, Derek C.; Mygind, Niels

    2004-01-01

    We begin by identifying a typical governance life-cycle, defined as changes in ownership structure, and including both the identity of the major owner and ownership concentration. The cycle is marked by key events and phases including start-up, initial growth, mature growth, and possibly a crisis......-sures for restructuring produce strong impulses for ownership changes. There is limited possibility for external finance because of the embryonic development of the banking system and the capital markets during early transition. The governance cycle is also influenced by specific features of the institutional, cultural...

  10. Life-cycle cost analysis of adsorption cycles for desalination

    KAUST Repository

    Thu, Kyaw

    2010-08-01

    This paper presents the thermo-economic analysis of the adsorption desalination (AD) cycle that is driven by low-temperature waste heat from exhaust of industrial processes or renewable sources. The AD cycle uses an adsorbent such as the silica gel to desalt the sea or brackish water. Based on an experimental prototype AD plant, the life-cycle cost analysis of AD plants of assorted water production capacities has been simulated and these predictions are translated into unit cost of water production. Our results show that the specific energy consumption of the AD cycle is 1.38 kWh/m3 which is the lowest ever reported. For a plant capacity of 1000 m3/d, the AD cycle offers a unit cost of $0.457/m3 as compared to more than $0.9 for the average RO plants. Besides being cost-effective, the AD cycle is also environment-friendly as it emits less CO2 emission per m3 generated, typically 85% less, by comparison to an RO process. © 2010 Desalination Publications.

  11. Successful ageing

    DEFF Research Database (Denmark)

    Bülow, Morten Hillgaard; Söderqvist, Thomas

    2014-01-01

    Since the late 1980s, the concept of ‘ successful ageing’ has set the frame for discourse about contemporary ageing research. Through an analysis of the reception to John W. Rowe and Robert L. Kahn's launch of the concept of ‘ successful ageing’ in 1987, this article maps out the important themes...... strategies; and the importance of individual, societal and scientific conceptualisations and understandings of ageing. By presenting an account of the recent historical uses, interpretations and critiques of the concept, the article unfolds the practical and normative complexities of ‘ successful ageing’....... and discussions that have emerged from the interdisciplinary field of ageing research. These include an emphasis on interdisciplinarity; the interaction between biology, psycho-social contexts and lifestyle choices; the experiences of elderly people; life-course perspectives; optimisation and prevention...

  12. Aging Differently

    DEFF Research Database (Denmark)

    Zajitschek, Felix; Jin, Tuo; Colchero, Fernando

    2014-01-01

    Diet effects on age-dependent mortality patterns are well documented in a large number of animal species, but studies that look at the effects of nutrient availability on late-life mortality plateaus are lacking. Here, we focus on the effect of dietary protein content (low, intermediate, and high...... based on Bayesian inference of age-specific mortality rates and found a deceleration of late-life mortality rates on all diets in males but only on the intermediate (standard) diet in females. The difference in mortality rate deceleration between males and females on extreme diets suggests...

  13. [Market and ageing].

    Science.gov (United States)

    Joël, M-E

    2005-06-01

    Ageing can be defined as growth of the proportion of elderly people in the population, but also as a group of transformations in life cycles: older age at time of first job, marriage, birth of first child, early retirement, longer life expectancy, active retirement, greater number of dependent persons. The economic impact of the ageing population has been extensively studied from the perspective of the social security fund. In France and in most developed countries, population ageing has considerably destabilized social accounting creating a gap between a system thought out after WWII and the present social environment. The current response of social security system to elderly person's needs is considered inadequate. There are however other consequences of ageing. It is important to measure the upheaval caused by longer life expectancy and changing life stages on all markets. Three kinds of markets are involved in different ways: job market, services market for the elderly and all goods market for seniors and golden aged. Many studies have focused on the links between economic production and physiological ageing. The traditional organisation of working conditions stresses working intensity over experience, young workers'capabilities over than those of older workers. The link between age and the job market can also be analyzed by considering supply and demand for employment for workers over 50. Another question is the workforce shortage forecasted in some sectors (health and social sectors in particular) and the role of immigration. Growth in the supply of long-term care will require restructuring of the sector's logistics and financing. Certain trends are appearing: government authorities are reducing their supply of services, private production is increasing, public financing is being maintained, and individual contributions are growing while the role of insurance has remained stagnant. A qualitative analysis of the markets also shows heterogeneous workers

  14. The role of senescent cells in ageing

    NARCIS (Netherlands)

    Deursen, J.M.A. van

    2014-01-01

    Cellular senescence has historically been viewed as an irreversible cell-cycle arrest mechanism that acts to protect against cancer, but recent discoveries have extended its known role to complex biological processes such as development, tissue repair, ageing and age-related disorders. New insights

  15. Ovarian Aging : Mechanisms and Clinical Consequences

    NARCIS (Netherlands)

    Broekmans, F. J.; Soules, M. R.; Fauser, B. C.

    Menopause is the final step in the process referred to as ovarian ageing. The age related decrease in follicle numbers dictates the onset of cycle irregularity and the final cessation of menses. The parallel decay in oocyte quality contributes to the gradual decline in fertility and the final

  16. [Forest carbon cycle model: a review].

    Science.gov (United States)

    Wang, Ping

    2009-06-01

    Forest carbon cycle is one of the important items in the research of terrestrial carbon cycle, while carbon cycle model is an important means in studying the carbon cycle mechanisms of forest ecosystem and in estimating carbon fluxes. Based on the sum-up of main carbon cycle models, this paper classified the forest carbon cycle models into two categories, i.e., patch scale forest carbon cycle models and regional scale terrestrial carbon cycle models, with their features commented. The future development trend in the research of forest carbon cycle models in China was discussed.

  17. Life Cycle Costing: An Introduction

    DEFF Research Database (Denmark)

    Rödger, Jan-Markus; Kjær, Louise Laumann; Pagoropoulos, Aris

    2018-01-01

    The chapter gives an introduction to life cycle costing (LCC) and how it can be used to support decision-making. It can form the economic pillar in a full life cycle sustainability assessment, but often system delimitations differ depending on the goal and scope of the study. To provide a profound...... understanding this chapter describes several approaches and terms, fundamental principles and different types of costs. A brief introduction is given to conventional LCC and societal LCC but the main focus is on environmental Life Cycle Costing (eLCC) as the LCC approach that is compatible with environmental...... Life Cycle Assessment (LCA) in terms of system delimitation. Differences are explained and addressed, and an overview is given of the main cost categories to consider from different user perspectives. As inventory data is often sensitive in financial analyses, a list of relevant databases is provided...

  18. Total Product Life Cycle (TPLC)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Total Product Life Cycle (TPLC) database integrates premarket and postmarket data about medical devices. It includes information pulled from CDRH databases...

  19. Optimisation of the nominal cycle

    CERN Document Server

    Redaelli, S

    2011-01-01

    The energy ramp and the betatron squeeze are critical phases of the LHC operation. During the squeeze, delicate optics manipulations take place when the stored energy is maximum. In 2010, ramp and squeeze were commissioned rapidly and smoothly became operational. On the other hand, during the first commissioning exercise, the focus was put on machine safety and on operational robustness rather then in efficiency for luminosity production. After having accumulated a full year of experience on the operational cycle and having gained important feedback on machine behaviour and operational procedures, it is now time to address the optimization of the LHC cycle, while still respecting safe boundaries. In this paper, the experience with the LHC operational cycle is reviewed, possible bottlenecks are identified and paths for improvements are addressed. Proposals for improvement are based on a critical look at the limiting factors encountered in the different phases of the cycle. More complex operation configurations...

  20. Endogenous, Imperfectly Competitive Business Cycles

    DEFF Research Database (Denmark)

    Whitta-Jacobsen, Hans Jørgen

    We investigate how imperfect competition affects the occurrence and the properties of endogenous, rational expectations business cycles in an overlapping generations model with constant returns to scale in production. The model has explicit product and labor markets all characterized...

  1. Mirador - Carbon Cycle and Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. This Focus Area deals with the cycling of carbon in reservoirs and ecosystems as it changes naturally, is changed by humans,...

  2. Revenue cycle management, Part II.

    Science.gov (United States)

    Crew, Matt

    2007-01-01

    The proper management of your revenue cycle requires the application of "best practices" and the continual monitoring and measuring of the entire cycle. The correct technology will enable you to gain the insight and efficiencies needed in the ever-changing healthcare economy. The revenue cycle is a process that begins when you negotiate payor contracts, set fees, and schedule appointments and continues until claims are paid in full. Every single step in the cycle carries equal importance. Monitoring all phases and a commitment to continually communicating the results will allow you to achieve unparalleled success. In part I of this article, we explored the importance of contracting, scheduling, and case management as well as coding and clinical documentation. We will now take a closer look at the benefits charge capture, claim submission, payment posting, accounts receivable follow-up, and reporting can mean to your practice.

  3. Hamiltonian cycles in polyhedral maps

    Indian Academy of Sciences (India)

    Dipendu Maity

    2017-08-24

    contractible separating Hamiltonian cycles; proper graphs in polyhedral maps. Mathematics Subject Classification. 57M20, 57N05, 05C38. 1. Introduction and definitions. By a topological graph we mean a representation of a graph in ...

  4. Mirador - Water and Energy Cycles

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Through water and energy cycle research we can improve hurricane prediction, quantify tropical rainfall and eventually begin...

  5. Towards Life Cycle Sustainability Assessment

    Directory of Open Access Journals (Sweden)

    Marzia Traverso

    2010-10-01

    Full Text Available Sustainability is nowadays accepted by all stakeholders as a guiding principle for both public policy making and corporate strategies. However, the biggest challenge for most organizations remains in the real and substantial implementation of the sustainability concept. The core of the implementation challenge is the question, how sustainability performance can be measured, especially for products and processes. This paper explores the current status of Life Cycle Sustainability Assessment (LCSA for products and processes. For the environmental dimension well established tools like Life Cycle Assessment are available. For the economic and social dimension, there is still need for consistent and robust indicators and methods. In addition to measuring the individual sustainability dimensions, another challenge is a comprehensive, yet understandable presentation of the results. The “Life Cycle Sustainability Dashboard” and the “Life Cycle Sustainability Triangle” are presented as examples for communication tools for both experts and non expert stakeholders.

  6. Venus Altitude Cycling Balloon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ISTAR Group ( IG) and team mate Thin Red Line Aerospace (TRLA) propose a Venus altitude cycling balloon (Venus ACB), an innovative superpressure balloon...

  7. Leptin controls hair follicle cycling.

    Science.gov (United States)

    Watabe, Reiko; Yamaguchi, Takashi; Kabashima-Kubo, Rieko; Yoshioka, Manabu; Nishio, Daisuke; Nakamura, Motonobu

    2014-04-01

    Leptin is a cytokine well known for its ability to control body weight and energy metabolism. Several lines of evidence have recently revealed that leptin also plays an important role in wound healing and immune modulation in skin. Sumikawa et al. Exp Dermatol 2014 evaluated the effect of leptin on hair follicle cycling using mutant and wild-type mice. They report that leptin is produced in dermal papilla cells in hair follicles and that leptin receptor-deficient db/db mice show an abnormality in hair follicle cycling. Moreover, leptin injection induced the transition into the growth stage of the hair cycle (anagen). On this basis, it now deserves exploration whether leptin-mediated signalling is a key stimulus for anagen induction and whether this may be targeted to manage human hair disorders with defect in the control of hair follicle cycling. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. (Auto)Ethnographies and Cycling

    DEFF Research Database (Denmark)

    Larsen, Jonas

    2014-01-01

    This article discusses the formation, salience and reformation of everyday bodily routines and resources in relation to cycling; it also examines how we can study them ethnographically in different places. I discuss forms of embodied, sensuous and mobile ethnography that can illuminate how routines......, habits and affective capacities of cycling are cultivated and performed. The article argues that autoethnography is particularly apt at illuminating the embodied qualities of movement, and it sits within established ethnographies of ‘excising’ and ‘mobile bodies’. In the second part of the article, I...... draw upon ongoing autoethnographies of cycling in a familiar place (my hometown, Copenhagen) and by learning to cycle ‘out-of-place’ (in London) and ‘in-a-new–way’ (when commuting long distance on a racer bike). The study challenges static notions of the body by analysing how cyclists’ (and researchers...

  9. Air Quality Management Process Cycle

    Science.gov (United States)

    Air quality management are activities a regulatory authority undertakes to protect human health and the environment from the harmful effects of air pollution. The process of managing air quality can be illustrated as a cycle of inter-related elements.

  10. IS BLOOD LACTATE REMOVAL DURING WATER IMMERSED CYCLING FASTER THAN DURING CYCLING ON LAND?

    Directory of Open Access Journals (Sweden)

    Fabrízio Di Masi

    2007-06-01

    Full Text Available The aim of the present study was to compare lactate removal during active recovery performed during cycling in water immersion (CW and during cycling on land (CL, after a similar exercise bout in male adults. Eleven healthy and physically active men, aged between 20 and 26 years old participated in the experiment. Before the experimental tests, the ventilatory threshold of the subjects was determined. Each subject completed the experimental tests twice, with one week separating the two periods of experiment. The subjects exercised on the treadmill during 6 min at a speed 10% above the speed corresponding to their ventilatory threshold. Subsequently, the subjects recovered from the exercise bout either on a stationary bike (CL or on a aquatic-specific bike (CW. On the subsequent week the subjects performed the same protocol but with a different recovery condition. Recovery condition assignment for the first test was counterbalanced (six subjects started with one condition and five with the other. Capillary blood samples were collected after each test and during the recovery period (at 3, 6, 9 and 15 minutes and blood lactate was measured. The blood lactate values during CW were lower than during CL and significant differences were observed at the 6th minute (p < 0.05 and at the 15th minute of recovery (p < 0.05. Therefore, we may conclude that active recovery using cycling in water immersion may be more efficient than cycling on land for blood lactate removal.

  11. Weak ionization of the global ionosphere in solar cycle 24

    Directory of Open Access Journals (Sweden)

    Y. Q. Hao

    2014-07-01

    Full Text Available Following prolonged and extremely quiet solar activity from 2008 to 2009, the 24th solar cycle started slowly. It has been almost 5 years since then. The measurement of ionospheric critical frequency (foF2 shows the fact that solar activity has been significantly lower in the first half of cycle 24, compared to the average levels of cycles 19 to 23; the data of global average total electron content (TEC confirm that the global ionosphere around the cycle 24 peak is much more weakly ionized, in contrast to cycle 23. The weak ionization has been more notable since the year 2012, when both the ionosphere and solar activity were expected to be approaching their maximum level. The undersupply of solar extreme ultraviolet (EUV irradiance somewhat continues after the 2008–2009 minimum, and is considered to be the main cause of the weak ionization. It further implies that the thermosphere and ionosphere in the first solar cycle of this millennium would probably differ from what we have learned from the previous cycles of the space age.

  12. Inflation Targeting and Business Cycle Synchronization

    OpenAIRE

    Flood, Robert P; Rose, Andrew K

    2009-01-01

    Inflation targeting seems to have a small but positive effect on the synchronization of business cycles; countries that target inflation seem to have cycles that move slightly more closely with foreign cycles. Thus the advent of inflation targeting does not explain the decoupling of global business cycles, for two reasons. Indeed business cycles have not in fact become less synchronized across countries.

  13. Detonation Jet Engine. Part 1--Thermodynamic Cycle

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

  14. Equipment life cycle costs minimised.

    Science.gov (United States)

    Kuligowski, Sharon

    2004-11-01

    With the cost of energy now a major component of building operating costs, NHS Trust managers increasingly focus on estimating total life cycle costs of equipment such as boiler room and heat, steam and incineration plant. "Life cycle costing" is a broad term and encompasses a wide range of techniques that take into account both initial and future costs as well as the savings of an investment over a period of time.

  15. The NEWS Water Cycle Climatology

    Science.gov (United States)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  16. A biogeochemical cycle for aluminium?

    Science.gov (United States)

    Exley, Christopher

    2003-09-15

    The elaboration of biogeochemical cycles for elements which are known to be essential for life has enabled a broad appreciation of the homeostatic mechanisms which underlie element essentiality. In particular they can be used effectively to identify any part played by human activities in element cycling and to predict how such activities might impact upon the lithospheric and biospheric availability of an element in the future. The same criteria were the driving force behind the construction of a biogeochemical cycle for aluminium, a non-essential element which is a known ecotoxicant and a suspected health risk in humans. The purpose of this exercise was to examine the concept of a biogeochemical cycle for aluminium and not to review the biogeochemistry of this element. The cycle as presented is rudimentary and qualitative though, even in this nascent form, it is informative and predictive and, for these reasons alone, it is deserving of future quantification. A fully fledged biogeochemical cycle for aluminium should explain the biospheric abundance of this element and whether we should expect its (continued) active involvement in biochemical evolution.

  17. Rapid increases in training load affects markers of skeletal muscle damage and mechanical performance

    DEFF Research Database (Denmark)

    Kamandulis, Sigitas; Snieckus, Audrius; Venckunas, Tomas

    2012-01-01

    a program involving a rapid stepwise increase in the number of jumps, drop height, and squat depth, and the addition of weight. Concentric, isometric maximal voluntary contraction (MVC), and stimulated knee extension torque were measured before and 10 min after each session. Muscle soreness and plasma...... creatine kinase activity were assessed after each session. Steep increments in stretch-shortening exercise load in sessions 4 and 7 amplified the postexercise decrease in stimulated muscle torque and slightly increased muscle soreness but had a minimal effect on the recovery of MVC and stimulated torque......The aim of the present study was to monitor the changes in indirect markers of muscle damage during 3 weeks (nine training sessions) of stretch-shortening (drop jump) exercise with constant load alternated with steep increases in load. Physically active men (n = 9, mean age 19.1 years) performed...

  18. Very high cycle fatigue testing of concrete using ultrasonic cycling

    Energy Technology Data Exchange (ETDEWEB)

    Karr, Ulrike; Schuller, Reinhard; Fitzka, Michael; Mayer, Herwig [Univ. of Natural Resources and Life Sciences, Vienna (Austria). Inst. of Physics and Materials Science; Denk, Andreas; Strauss, Alfred [Univ. of Natural Resources and Life Sciences, Vienna (Austria)

    2017-06-01

    The ultrasonic fatigue testing method has been further developed to perform cyclic compression tests with concrete. Cylindrical specimens vibrate in resonance at a frequency of approximately 20 kHz with superimposed compressive static loads. The high testing frequency allows time-saving investigations in the very high cycle fatigue regime. Fatigue tests were carried out on ''Concrete 1'' (compressive strength f{sub c} = 80 MPa) and ''Concrete 2'' (f{sub c} = 107 MPa) under purely compressive loading conditions. Experiments at maximum compressive stresses of 0.44 f{sub c} (Concrete 1) and 0.38 f{sub c} (Concrete 2) delivered specimen failures above 109 cycles, indicating that no fatigue limit exists for concrete below one billion load cycles. Resonance frequency, power required to resonate the specimen and second order harmonics of the vibration are used to monitor fatigue damage in situ. Specimens were scanned by X-ray computed tomography prior to and after testing. Fatigue cracks were produced by ultrasonic cycling in the very high cycle fatigue regime at interfaces of grains as well as in cement. The possibilities as well as limitations of ultrasonic fatigue testing of concrete are discussed.

  19. Cytological Determination Of The Estrus Cycle In Guinea Pigs ...

    African Journals Online (AJOL)

    A cytologic study was carried out to determine the Estrus cycle in 5 female guinea pigs of reproductive age, for a period of 28 days in the Animal House of the College of Medicine, University of Nigeria, Enugu Campus, Enugu. Vaginal smears were collected from the animals and made on clean grease-free slides, fixed in ...

  20. Annual cycle of the southern elephant seal Mirounga leonina (Linn ...

    African Journals Online (AJOL)

    The annual cycle of southern elephant seals, Mirounga leonina, was studied at Marion Island (46°54'S, 37°45' E), between August 1973 and December 1976. Data on the breeding and moulting haul-out of different age and sex classes were obtained by conducting once weekly censuses in a selected study area.

  1. Surface-Cycling of Rhenium and its Isotopes

    Science.gov (United States)

    2009-06-01

    R., Ruiz, J., and Tornos, F. (1999), Age and sources of the ore at Tharsis and Rio Tinto, Iberian Pyrite Belt, from Re-Os isotopes, Mineralium...R. J., Orians, G. H., and Wolfe , G. V. (eds.), Global Biogeochemical Cycles, chap. 4, Academic Press, 55–72. [91] Rosman, K. J. R. and Taylor, P. D

  2. Unbalanced Growth, Senescence and Aging.

    Science.gov (United States)

    Polymenis, Michael; Kennedy, Brian K

    2017-01-01

    Usually, cells balance their growth with their division. Coordinating growth inputs with cell division ensures the proper timing of division when sufficient cell material is available and affects the overall rate of cell proliferation. At a very fundamental level, cellular replicative lifespan-defined as the number of times a cell can divide, is a manifestation of cell cycle control. Hence, control of mitotic cell divisions, especially when the commitment is made to a new round of cell division, is intimately linked to replicative aging of cells. In this chapter, we review our current understanding, and its shortcomings, of how unbalanced growth and division, can dramatically influence the proliferative potential of cells, often leading to cellular and organismal aging phenotypes. The interplay between growth and division also underpins cellular senescence (i.e., inability to divide) and quiescence, when cells exit the cell cycle but still retain their ability to divide.

  3. The Sphinx's Riddle: Life and Career Cycles.

    Science.gov (United States)

    Burack, Elmer H.

    1984-01-01

    Career cycles should be considered apart from life cycles, even though the two are interrelated. This essay examines five theories about life and career cycles, and offers insights into their limitations and potential uses. (JB)

  4. The Abbreviated Pluripotent Cell Cycle

    Science.gov (United States)

    Kapinas, Kristina; Grandy, Rodrigo; Ghule, Prachi; Medina, Ricardo; Becker, Klaus; Pardee, Arthur; Zaidi, Sayyed K.; Lian, Jane; Stein, Janet; van Wijnen, Andre; Stein, Gary

    2013-01-01

    Human embryonic stem cells and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory andstructural. The primary temporal context that the pluripotent self-renewal cell cycle of human embryonic stem cells (hESCs) is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the ESC cell cycle. This supports the requirements of pluripotent cells to self propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated embryonic stem cell cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle. PMID:22552993

  5. Enhanced absorption cycle computer model

    Science.gov (United States)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  6. 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.

  7. Physiological responses and perceived exertion during cycling with superimposed electromyostimulation.

    Science.gov (United States)

    Wahl, Patrick; Schaerk, Jonas; Achtzehn, Silvia; Kleinöder, Heinz; Bloch, Wilhelm; Mester, Joachim

    2012-09-01

    The goal of the study was to evaluate and to quantify the effects of local electromyostimulation (EMS) during cycling on the cardiorespiratory system, muscle metabolism, and perceived exertion compared with cycling with no EMS. Ten healthy men (age: 24.6 ± 3.2 years, V[Combining Dot Above]O2max: 54.1 ± 6.0 ml·min·kg) performed 3 incremental cycle ergometer step tests, 1 without and 2 with EMS (30 and 85 Hz) until volitional exhaustion. Lactate values and respiratory exchange ratio were significantly higher at intensities ≥75% peak power output (PPO) when EMS was applied. Bicarbonate concentration, base excess (BE), and Pco2 were significantly lower when EMS was applied compared with the control at intensities ≥75% PPO. Saliva cortisol levels increased because of the exercise but were unaffected by EMS. Furthermore, EMS showed greater effects on CK levels 24 hours postexercise than normal cycling did. Rating of perceived exertion was significantly higher at 100% PPO with EMS. No statistical differences were found for heart rate, pH, and Po2 between the tested cycling modes. The main findings of this study are greater metabolic changes (lactate, respiratory exchange ratio, BE, (Equation is included in full-text article.), Pco2) during cycling with EMS compared with normal cycling independent of frequency, mainly visible at higher work rates. Because metabolic alterations are important for the induction of cellular signaling cascades and adaptations, these results lead to the hypothesis that applied EMS stimulations during cycling exercise might be an enhancing stimulus for skeletal muscle metabolism and related adaptations. Thus, superimposed EMS application during cycling could be beneficial to aerobic performance enhancements in athletes and in patients who cannot perform high workloads. However, the higher demand on skeletal muscles involved must be considered.

  8. What interventions increase commuter cycling? A systematic review.

    Science.gov (United States)

    Stewart, Glenn; Anokye, Nana Kwame; Pokhrel, Subhash

    2015-08-14

    To identify interventions that will increase commuter cycling. All settings where commuter cycling might take place. Adults (aged 18+) in any country. Individual, group or environmental interventions including policies and infrastructure. A wide range of 'changes in commuter cycling' indicators, including frequency of cycling, change in workforce commuting mode, change in commuting population transport mode, use of infrastructure by defined populations and population modal shift. 12 studies from 6 countries (6 from the UK, 2 from Australia, 1 each from Sweden, Ireland, New Zealand and the USA) met the inclusion criteria. Of those, 2 studies were randomised control trials and the remainder preintervention and postintervention studies. The majority of studies (n=7) evaluated individual-based or group-based interventions and the rest environmental interventions. Individual-based or group-based interventions in 6/7 studies were found to increase commuter cycling of which the effect was significant in only 3/6 studies. Environmental interventions, however, had small but positive effects in much larger but more difficult to define populations. Almost all studies had substantial loss to follow-up. Despite commuter cycling prevalence varying widely between countries, robust evidence of what interventions will increase commuter cycling in low cycling prevalence nations is sparse. Wider environmental interventions that make cycling conducive appear to reach out to hard to define but larger populations. This could mean that environmental interventions, despite their small positive effects, have greater public health significance than individual-based or group-based measures because those interventions encourage a larger number of people to integrate physical activity into their everyday lives. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. [Hyperprolactinemia and disorders of the menstrual cycle].

    Science.gov (United States)

    Topalski-Fistes, N; Bujas, M; Maticki-Sekulić, M; Suvacarev, S

    1999-01-01

    The authors presented physiological conditions associated with increased prolactin values (sleep, stress, hypoglycemia, nipples stimulation, pregnancy and lactation) as well as the causes of pathological hyperprolactinemia. The results of radioimmunoassay study have been analyzed in concern to the values of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL) obtained from the serum of 100 women with increased PRL levels. The "HOECHT" sets were used for the analysis, whereas the values up to 20.9 microgrammes per litre were rated normal. The patients were distributed into 4 groups in concern to the level of PRL increase: 1st group--twenty (n = 20) patients with PRL values from 21-29.9 micrograms/l, 90 blood samples analyzed; 2nd group-forty (n = 40) patients with PRL values f; 30-49.9 micrograms/l, 183 blood samples analyzed; 3rd group--twenty (n = 20) patients with PRL values from 50-99.9 micrograms/l, 83 blood samples analyzed; 4th group--twenty patients (n = 20) with PRL values more than 100 micrograms/l, 78 blood samples analyzed. The values of FSH and LH recorded in the women with hyperprolactinemia were compared with mean values of the same hormones presented in IU/l from the follicular phase of the cycle in the control group which comprised 50 women of reproductive age having normal ovulatory menstrual cycle. The mean values of FSH and LH in the 1st group have not presented with statistically significant difference in relation to the control group. Prevalence of menstrual disorders was 30%, which was statistically significantly higher than in general population. FSH values in the 2nd group were almost the same as in the control group whereas the values of LH were significantly higher. The rate of polycistic ovary syndrome (PCOS) in this group has been significant, also the increased rate of anovulatory cycles from 30 to 67.5%. A mild increase of menstrual cycle rhythm disorders, from 35 to 40% has been recorded. The values of FSH

  10. Focused training boosts revenue cycle skills, accountability.

    Science.gov (United States)

    Richmond, Craig

    2011-09-01

    In 2009, the MetroHealth System took its first steps toward creating a comprehensive revenue cycle university, with the goal of developing revenue cycle staff talent and achieving best-in-class revenue cycle operations. MetroHealth became a beta site for HFMA's online Credentialed Revenue Cycle Representative (CRCR) program, and asked its revenue cycle leaders to present classes on key revenue cycle issues. As of June 2011, 62 percent of 122 revenue cycle employees who had taken the CRCR course passed the exam. The CRCR designation is now a prerequisite for career advancement in certain revenue cycle areas at MetroHealth.

  11. Origins of the supercontinent cycle

    Directory of Open Access Journals (Sweden)

    R. Damian Nance

    2013-07-01

    Full Text Available The supercontinent cycle, by which Earth history is seen as having been punctuated by the episodic assembly and breakup of supercontinents, has influenced the rock record more than any other geologic phenomena, and its recognition is arguably the most important advance in Earth Science since plate tectonics. It documents fundamental aspects of the planet's interior dynamics and has charted the course of Earth's tectonic, climatic and biogeochemical evolution for billions of years. But while the widespread realization of the importance of supercontinents in Earth history is a relatively recent development, the supercontinent cycle was first proposed thirty years ago and episodicity in tectonic processes was recognized long before plate tectonics provided a potential explanation for its occurrence. With interest in the supercontinent cycle gaining momentum and the literature expanding rapidly, it is instructive to recall the historical context from which the concept developed. Here we examine the supercontinent cycle from this perspective by tracing its development from the early recognition of long-term episodicity in tectonic processes, through the identification of tectonic cycles following the advent of plate tectonics, to the first realization that these phenomena were the manifestation of episodic supercontinent assembly and breakup.

  12. Antifreeze life cycle assessment (LCA

    Directory of Open Access Journals (Sweden)

    Kesić Jelena

    2005-01-01

    Full Text Available Antifreeze based on ethylene glycol is a commonly used commercial product The classification of ethylene glycol as a toxic material increased the disposal costs for used antifreeze and life cycle assessment became a necessity. Life Cycle Assessment (LCA considers the identification and quantification of raw materials and energy inputs and waste outputs during the whole life cycle of the analyzed product. The objectives of LCA are the evaluation of impacts on the environment and improvements of processes in order to reduce and/or eliminate waste. LCA is conducted through a mathematical model derived from mass and energy balances of all the processes included in the life cycle. In all energy processes the part of energy that can be transformed into some other kind of energy is called exergy. The concept of exergy considers the quality of different types of energy and the quality of different materials. It is also a connection between energy and mass transformations. The whole life cycle can be described by the value of the total loss of exergy. The physical meaning of this value is the loss of material and energy that can be used. The results of LCA are very useful for the analyzed products and processes and for the determined conditions under which the analysis was conducted. The results of this study indicate that recycling is the most satisfactory solution for the treatment of used antifreeze regarding material and energy consumption but the re-use of antifreeze should not be neglected as a solution.

  13. The chromosome cycle of prokaryotes

    Science.gov (United States)

    Kuzminov, Andrei

    2013-01-01

    Summary In both eukaryotes and prokaryotes, chromosomal DNA undergoes replication, condensation-decondensation and segregation, sequentially, in some fixed order. Other conditions, like sister-chromatid cohesion (SCC), may span several chromosomal events. One set of these chromosomal transactions within a single cell cycle constitutes the “chromosome cycle”. For many years it was generally assumed that the prokaryotic chromosome cycle follows major phases of the eukaryotic one: -replication-condensation-segregation-(cell division)-decondensation-, with SCC of unspecified length. Eventually it became evident that, in contrast to the strictly consecutive chromosome cycle of eukaryotes, all stages of the prokaryotic chromosome cycle run concurrently. Thus, prokaryotes practice “progressive” chromosome segregation separated from replication by a brief SCC, and all three transactions move along the chromosome at the same fast rate. In other words, in addition to replication forks, there are “segregation forks” in prokaryotic chromosomes. Moreover, the bulk of prokaryotic DNA outside the replication-segregation transition stays compacted. I consider possible origins of this concurrent replication-segregation and outline the “nucleoid administration” system that organizes the dynamic part of the prokaryotic chromosome cycle. PMID:23962352

  14. Air bottoming cycle, an alternative to combined cycles. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kaikko, J. [Royal Inst. of Techn., Stockholm (Sweden). Dept. of Energy Technology

    2001-10-01

    In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or

  15. Air bottoming cycle, an alternative to combined cycles. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kaikko, J. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

    2002-02-01

    In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or

  16. Aging Perspectives

    Directory of Open Access Journals (Sweden)

    Theodore D Cosco

    2014-05-01

    Full Text Available Despite the proliferation of successful ageing (SA research, the literature is dominated by researcher-driven Anglophone conceptualisations. To date, lay perspectives of SA have not been examined in Europe or Turkey. The current study aims to conduct a mixed-methods examination of conceptualisations of SA in seven underrepresented countries. Using snowball sampling via social media sites, an online survey consisting of established closed-ended and open-ended items – translated into seven languages – was administered. Grounded theory methods and descriptive statistics were used to analyse qualitative and quantitative data, respectively.

  17. Adiposity and sex hormones across the menstrual cycle: the BioCycle Study.

    Science.gov (United States)

    Yeung, E H; Zhang, C; Albert, P S; Mumford, S L; Ye, A; Perkins, N J; Wactawski-Wende, J; Schisterman, E F

    2013-02-01

    To investigate the influence of adiposity on patterns of sex hormones across the menstrual cycle among regularly menstruating women. The BioCycle Study followed 239 healthy women for 1-2 menstrual cycles, with up to eight visits per cycle timed using fertility monitors. Serum estradiol (E2), progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) were measured at each visit. Adiposity was measured by anthropometry and by dual energy X-ray absorptiometry (DXA). Differences in hormonal patterns by adiposity measures were estimated using nonlinear mixed models, which allow for comparisons in overall mean levels, amplitude (i.e., lowest to highest level within each cycle) and shifts in timing of peaks while adjusting for age, race, energy intake and physical activity. Compared with normal weight women (n=154), obese women (body mass index (BMI) 30 kg m(-2), n=25) averaged lower levels of progesterone (-15%, P=0.003), LH (-17%, P=0.01), FSH (-23%, P=0.001) and higher free E2 (+22%, P=0.0001) across the cycle. To lesser magnitudes, overweight women (BMI: 25-30, n=60) also exhibited differences in the same directions for mean levels of free E2, FSH and LH. Obese women experienced greater changes in amplitude of LH (9%, P=0.002) and FSH (8%, P=0.004), but no differences were observed among overweight women. Higher central adiposity by top compared to bottom tertile of trunk-to-leg fat ratio by DXA was associated with lower total E2 (-14%, P=0.005), and FSH (-15%, P=0.001). Peaks in FSH and LH occurred later (∼0.5 day) in the cycle among women with greater central adiposity. Greater total and central adiposity were associated with changes in mean hormone levels. The greater amplitudes observed among obese women suggest compensatory mechanisms at work to maintain hormonal homeostasis. Central adiposity may be more important in influencing timing of hormonal peaks than total adiposity.

  18. Modeling the Nuclear Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; A. M. Yacout; G. E. Matthern; S. J. Piet; A. Moisseytsev

    2005-07-01

    The Advanced Fuel Cycle Initiative is developing a system dynamics model as part of their broad systems analysis of future nuclear energy in the United States. The model will be used to analyze and compare various proposed technology deployment scenarios. The model will also give a better understanding of the linkages between the various components of the nuclear fuel cycle that includes uranium resources, reactor number and mix, nuclear fuel type and waste management. Each of these components is tightly connected to the nuclear fuel cycle but usually analyzed in isolation of the other parts. This model will attempt to bridge these components into a single model for analysis. This work is part of a multi-national laboratory effort between Argonne National Laboratory, Idaho National Laboratory and United States Department of Energy. This paper summarizes the basics of the system dynamics model and looks at some results from the model.

  19. Proliferation resistance fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. S.; Ko, W. I

    1999-02-01

    The issues of dual use in nuclear technology are analysed for nuclear fuel cycle with special focus on uranium enrichment and spent fuel reprocessing which are considered as the most sensitive components in terms of vulnerability to diversion. Technical alternatives to mitigrate the vulnerability, as has been analysed in depth during the NASAP and INFCE era in the late seventies, are reviewed to characterize the DUPIC fuel cycle alternative. On the other hand, the new realities in nuclear energy including the disposition of weapon materials as a legacy of cold war are recast in an angle of nuclear proliferation resistance and safeguards with a discussion on the concept of spent fuel standard concept and its compliance with the DUPIC fuel cycle technology. (author)

  20. Aging Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Inchang Cho

    2013-09-01

    Full Text Available In performing upper blepharoplasty in the elderly, looking younger and keeping the eyelidsharmonious with the rest of the face have to be achieved at the same time. The most importantgoal in upper blepharoplasty for aging is correcting the drooping upper eyelid skin, and inthis process, the surgeon may or may not create a double eyelid fold. The pros and cons haveto be fully discussed with the patient, but the author personally prefers creating a doublefold unless the patient refuses, because it is efficient in correcting and preventing furtherdrooping of the skin. In most patients, the brow is elevated to compensate for the droopingeyelid, and when the drooping is corrected, brow ptosis may ensue. The surgeon has to preparefor these consequences before performing the procedure, and estimate the exact amountof skin to be excised. In the elderly, the skin and the orbicularis oculi muscle is thin, with adecreased amount of subcutaneous fat and retro-orbicularis oculi fat, and in most cases,excision of the skin alone is enough to correct the deformity. Removing large portions ofsoft tissue may also prolong the recovery period. Unlike younger patients, the lower skinflap should not be stretched too much in the elderly, as it may create an aggressive lookingappearance. A few wrinkles in the lower flap should remain untouched to create a naturallook. In this article, the author’s own methods of performing an aging blepharoplasty aredescribed specifically, with a step-by-step guide and surgical tips.

  1. Biogeochemical cycling and remote sensing

    Science.gov (United States)

    Peterson, D. L.

    1985-01-01

    Research is underway at the NASA Ames Research Center that is concerned with aspects of the nitrogen cycle in terrestrial ecosystems. An interdisciplinary research group is attempting to correlate nitrogen transformations, processes, and productivity with variables that can be remotely sensed. Recent NASA and other publications concerning biogeochemical cycling at global scales identify attributes of vegetation that could be related or explain the spatial variation in biologically functional variables. These functional variables include net primary productivity, annual nitrogen mineralization, and possibly the emission rate of nitrous oxide from soils.

  2. Business Cycles in Developing Countries

    DEFF Research Database (Denmark)

    Rand, John; Tarp, Finn

    2002-01-01

    than those of the rather uniform industrialized countries. Supply-side models are generally superior in explaining changes in output, but a “one-size fits all” approach in formulating policy is inappropriate. Our results also illustrate the critical importance of understanding business regularities......This paper demonstrates that developing countries differ considerably from their developed counterparts when focus is on the nature and characteristics of short run macroeconomic fluctuations. Cycles are generally shorter, and the stylized facts of business cycles across countries are more diverse...

  3. Simple ocean carbon cycle models

    Energy Technology Data Exchange (ETDEWEB)

    Caldeira, K. [Lawrence Livermore National Lab., CA (United States); Hoffert, M.I. [New York Univ., NY (United States). Dept. of Earth System Sciences; Siegenthaler, U. [Bern Univ. (Switzerland). Inst. fuer Physik

    1994-02-01

    Simple ocean carbon cycle models can be used to calculate the rate at which the oceans are likely to absorb CO{sub 2} from the atmosphere. For problems involving steady-state ocean circulation, well calibrated ocean models produce results that are very similar to results obtained using general circulation models. Hence, simple ocean carbon cycle models may be appropriate for use in studies in which the time or expense of running large scale general circulation models would be prohibitive. Simple ocean models have the advantage of being based on a small number of explicit assumptions. The simplicity of these ocean models facilitates the understanding of model results.

  4. Digital calculations of engine cycles

    CERN Document Server

    Starkman, E S; Taylor, C Fayette

    1964-01-01

    Digital Calculations of Engine Cycles is a collection of seven papers which were presented before technical meetings of the Society of Automotive Engineers during 1962 and 1963. The papers cover the spectrum of the subject of engine cycle events, ranging from an examination of composition and properties of the working fluid to simulation of the pressure-time events in the combustion chamber. The volume has been organized to present the material in a logical sequence. The first two chapters are concerned with the equilibrium states of the working fluid. These include the concentrations of var

  5. SNMR pulse sequence phase cycling

    Science.gov (United States)

    Walsh, David O; Grunewald, Elliot D

    2013-11-12

    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

  6. Development of soil properties and nitrogen cycling in created wetlands

    Science.gov (United States)

    Wolf, K.L.; Ahn, C.; Noe, G.B.

    2011-01-01

    Mitigation wetlands are expected to compensate for the loss of structure and function of natural wetlands within 5–10 years of creation; however, the age-based trajectory of development in wetlands is unclear. This study investigates the development of coupled structural (soil properties) and functional (nitrogen cycling) attributes of created non-tidal freshwater wetlands of varying ages and natural reference wetlands to determine if created wetlands attain the water quality ecosystem service of nitrogen (N) cycling over time. Soil condition component and its constituents, gravimetric soil moisture, total organic carbon, and total N, generally increased and bulk density decreased with age of the created wetland. Nitrogen flux rates demonstrated age-related patterns, with younger created wetlands having lower rates of ammonification, nitrification, nitrogen mineralization, and denitrification potential than older created wetlands and natural reference wetlands. Results show a clear age-related trajectory in coupled soil condition and N cycle development, which is essential for water quality improvement. These findings can be used to enhance N processing in created wetlands and inform the regulatory evaluation of mitigation wetlands by identifying structural indicators of N processing performance.

  7. Variation of fluorescence spectroscopy during the menstrual cycle

    Science.gov (United States)

    Macaulay, Calum; Richards-Kortum, Rebecca; Utzinger, Urs; Fedyk, Amanda; Neely Atkinson, E.; Cox, Dennis; Follen, Michele

    2002-06-01

    Cervical autofluorescence has been demonstrated to have potential for real-time diagnosis. Inter-patient and intra-patient variations in fluorescence intensity have been measured. Inter-patient measurements may vary by a factor of ten, while intra-patient measurements may vary by a factor of two. Age and menopausal status have been demonstrated to account for some of the variations, while race and smoking have not. In order to explore in detail the role of the menstrual cycle in intra-patient variation, a study was designed to measure fluorescence excitation emission matrices (EEMs) in patients daily throughout one cycle. Ten patients with a history of normal menstrual cycles and normal Papanicolaou smears underwent daily measurements of fluorescence EEMs from three colposcopically normal sites throughout one menstrual cycle. Changes in signals from porphyrin, NADH, and FAD fluorescence and blood absorption were noted when the data was viewed in a graphical format. Visually interpreted features of the EEMs in this graphical format did not appear to correlate with the day of the menstrual cycle with the exception that blood absorption features were more prominent during the menstrual phase (during which bleeding occurs), suggesting that measurements during the menstrual phase should be avoided. Variations in cycle date likely do not account for inter- or intra-patient variations.

  8. Ionizing radiation damage to cells: effects of cell cycle redistribution.

    Science.gov (United States)

    Chen, P L; Brenner, D J; Sachs, R K

    1995-04-01

    If a population of cycling cells is exposed to a fixed dose of ionizing radiation delivered over time T, it is sometimes observed that increasing T increases the amount of cell killing. This is essentially because at first the radiation preferentially kills cells in a sensitive portion of the cycle and the surviving, more resistant cells then have time to reach more sensitive stages. We refer to this effect as population resensitization, caused by redistribution within the cell cycle. We investigate the effect theoretically by employing the McKendrick-von Foerster equation for age-structured proliferating cell populations, generalized by introducing a radiation damage term. Within our formalism, we show that population resensitization occurs whenever: (a) prior to irradiation the cell population has the stable age-distribution approached asymptotically by an unirradiated population, and (b) T is sufficiently small. Examples and other cases are outlined. The methods of Volterra integral equations, renewal theory, and positive semigroup theory are applied. The effect of varying T is evaluated by considering the ultimate amplitude of the stable age-distribution population at times much greater than both the irradiation duration and the average cell-cycle time. The main biological limitations of the formalism are the following: considering only radiation damage which is not subject to enzymatic repair or quadratic misrepair, using an overly naive method of ensuring loss of cell cycle synchrony, neglecting nonlinear effects such as density inhibition of growth, and neglecting radiatively induced perturbations of the cell cycle. Possible methods for removing these limitations are briefly discussed.

  9. Global Links to Local Carbon Cycling Perturbation

    Science.gov (United States)

    Chen, J.; Montanez, I. P.; Wang, X.; Qi, Y.

    2016-12-01

    Carbon cycle perturbations recorded by stable carbon isotope excursions (CIEs) play an important role in understanding climate, oceanography, and the biosphere through time. Recent studies, however, reveal the influence of regional processes on apparent global CIEs. Deconvolving local/regional from global processes imprinted in the carbon isotopic records of sedimentary successions requires integrated sedimentologic, stratigraphic, and geochemical study. Here we present coupled C and Sr isotopic records of diagenetically screened micrite and brachiopods from late Mississippian shallow-marine, carbonate platform and contemporaneous carbonate slope successions from the east Paleotethys Ocean region (South China). These records reveal distinctly different signatures of the depositional response to the onset of Carboniferous glaciation. C and Sr isotopic compositions of the platform carbonates exhibit systematic fluctuations in step with inferred sea-level changes captured by depositional cycles. CIEs in the platform succession can be correlated to the contemporaneous C isotope record from the Antler carbonate ramp (Idaho, USA). In contrast, slope carbonate and conodont isotopic records exhibit minimal variability interpreted to record the open-ocean seawater composition. The isotopic disparity between successions is interpreted to record the influence of local depositional, but not diagenetic, processes operating on the carbonate platform in response to glacioeustasy. Variability in the nature of coupled isotopic and inferred sea level fluctuations is interpreted to record stepwise onset of the late Paleozoic ice age in the late Mississippian. Initial large magnitude shifts in C and Sr isotopic compositions of late Visean to early Serpukhovian carbonates correspond to 1 to 2 myr-scale cycles driven by the buildup of continental glaciers. Subsequent decreased magnitude of isotopic shifts coincident with a shift to shorter duration and smaller magnitude sea

  10. Changes in strength and power qualities over two years in volleyball players transitioning from junior to senior national team.

    Science.gov (United States)

    Sheppard, Jeremy M; Nolan, Emily; Newton, Robert U

    2012-01-01

    The purpose of this investigation was to examine the changes in performance indicators as they relate to strength and speed-strength development, over 2 years in a group of volleyball players who successfully transitioned from age group (U21) to senior national team in that time period. Sixteen male subjects (age: 18.5 ± 1.5 years, height: 2.00 ± 0.06 m, and weight: 88.4 ± 7.7 kg) participated in this 2-year longitudinal study. During the 24-month period of this investigation, all the subjects gained professional European contracts and also debuted with at least 1 senior national team match. These included, at a minimum, not only international friendly matches but also senior continental championships, World Championships, and the World Cup. Testing included 1 repetition maximum (1RM) and 3RM for the clean and squat, a maximum effort counter movement vertical jump (CMVJ), depth jump from a 0.35-m box (DJ), spike jump (with approach) (SPJ), and lower body speed-strength assessment with a body weight and body weight + 50% load. Large magnitude increases were observed for CMVJ, DJ, and SPJ over the 2-year period (d = 0.80, 0.82, and 0.94, respectively, p volleyball players must increase their CMVJ and SPJ. This is best accomplished through increasing lean mass, reducing fat mass, improving strength and speed strength, and developing high levels of stretch-load tolerance in stretch-shorten cycle activity.

  11. Risk factors on the menstrual cycle of healthy Taiwanese college nursing students.

    Science.gov (United States)

    Chang, Pei-Jen; Chen, Pau-Chung; Hsieh, Chia-Jung; Chiu, Li-Tan

    2009-12-01

    The purpose of this study was to explore risk factors, including age at menarche, body mass index (BMI), psychiatric stress and physical exercise on the menstrual cycle of healthy Taiwanese college nursing students. We conducted a cross-sectional survey involving 1300 female college students in the nursing curriculum between December 2002 and March 2003. We provided a structured questionnaire for each student. Information on the women's demographics, lifestyles and reproductive history related to menstrual cycle characteristics was requested. A total of 1095 healthy students were included in the analysis. A logistic regression was used to estimate the odds ratios for each of the menstrual cycle characteristics. We found that age at menarche, BMI and psychiatric stress were associated with menstrual cycle characteristics in healthy college nursing students. In addition to menarche at the age of 14 years or later, obesity and psychological stress, menarche before 12 years of age was an important risk factor for menstrual dysfunction. Moreover, obese students had the highest risk of having a longer cycle and cycle irregularity. Early menarche might be related to menstrual dysfunction in addition to late menarche, obesity and psychological stress. Moreover, obese students are at the highest risks for longer cycles and cycle irregularity.

  12. Life-Cycle Trade-Offs in Matrix Population-Models

    NARCIS (Netherlands)

    Van Tienderen, P.H.

    1995-01-01

    Matrix projections allow identification of those phases in the life cycle with a high potential impact on the population growth rate. This impact is assessed by the sensitivity or elasticity of the matrix elements that are computed from life cycle data such as age-dependent survival or fecundity.

  13. 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…

  14. Optimizing the aging, retirement, and pensions dilemma

    CERN Document Server

    Bertocchi, Marida; Ziemba, William T.

    2010-01-01

    A straightforward guide focused on life cycle investing-namely aging, retirement, and pensions Life cycle investing and the implications of aging, retirement, and pensions continues to grow in importance. With people living longer, the relative and absolute number of retirees is growing while the number of workers contributing to pension funds is declining. This reliable resource develops a detailed economic analysis-at the micro (individual) and macro (economy wide) levels-which addresses issues regarding the economics of an aging population. Topics touched upon include retirement and the associated health care funding of the aged as well as social security and the asset classes that are considered asset-liability choices over time. The probability of achieving adequate return patterns from various investment strategies and asset classes is reviewed Shares rich insights on the aging, retirement, and pensions dilemma An assessment of the resources the real economy will be able to commit to non-workers is prov...

  15. Cycling for transport and recreation: associations with socio-economic position, environmental perceptions, and psychological disposition.

    Science.gov (United States)

    Heesch, Kristiann C; Giles-Corti, Billie; Turrell, Gavin

    2014-06-01

    Interest is growing in promoting utility cycling (i.e., for transport) as a means of incorporating daily physical activity (PA) into people's lives, but little is known about correlates of utility cycling. Our primary aim was to examine cross-sectional relationships between socio-economic characteristics, neighborhood environment perceptions and psychological disposition with utility cycling (with or without additional recreational cycling). A secondary aim was to compare these relationships with those for recreation-only cycling. Baseline survey data (2007) from 10,233 participants in HABITAT, a multilevel longitudinal study of PA, sedentary behavior, and health in Brisbane adults aged 40-65years, were analyzed using multinomial regression modeling. Greater income, habitual PA, and positive beliefs about PA were associated with utility and recreation-only cycling (precreation-only cycling (precreational destinations) were associated with utility cycling (precreation-only cycling in Brisbane residents aged 40-65years. Tailored approaches appear to be required to promote utility and recreational cycling. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Prospects for Predicting Cycle 24

    Indian Academy of Sciences (India)

    We explain this by suggesting that the Babcock–Leighton mechanism of poloidal field generation from tilted active regions involves randomness, whereas the other aspects of the dynamo process are more ordered. To model actual cycles, we have to 'correct' our theoretical dynamo model by 'feeding' information about the ...

  17. The product life cycle revisited

    DEFF Research Database (Denmark)

    Ulhøi, John Parm

    1995-01-01

    Efter et introduktionsafsnit følger afsnit II, hvor der gives en historisk analyse af Life Cycle Assessment (LCA) og Environmental Impact Assessment (EIA). I afsnit III munder analysen ud i en vurdering af ligheder og forskelle mellem LCA analyser og EIA analyser, og en diskussion følger af...

  18. Energy Conservative Limit Cycle Oscillations

    NARCIS (Netherlands)

    Stramigioli, Stefano; van Dijk, Michel

    This paper shows how globally attractive limit cycle oscillations can be induced in a system with a nonlinear feedback element. Based on the same principle as the Van der Pol oscillator, the feedback behaves as a negative damping for low velocities but as an ordinary damper for high velocities. This

  19. Environmental life-cycle assessment

    Science.gov (United States)

    Kirchain, Randolph E., Jr.; Gregory, Jeremy R.; Olivetti, Elsa A.

    2017-07-01

    Concerns about the planet's health call for a careful evaluation of the environmental impact of materials choices. Life-cycle assessment is a tool that can help identify sustainable materials pathways by considering the burdens of materials both during production and as a product.

  20. Autoradiography and the Cell Cycle.

    Science.gov (United States)

    Jones, C. Weldon

    1992-01-01

    Outlines the stages of a cell biology "pulse-chase" experiment in which the students apply autoradiography techniques to learn about the concept of the cell cycle. Includes (1) seed germination and plant growth; (2) radioactive labeling and fixation of root tips; (3) feulgen staining of root tips; (4) preparation of autoradiograms; and…

  1. H gas turbine combined cycle

    Energy Technology Data Exchange (ETDEWEB)

    Corman, J. [General Electric Co., Schenectady, NY (United States)

    1995-10-01

    A major step has been taken in the development of the Next Power Generation System - {open_quotes}H{close_quotes} Technology Combined Cycle. This new gas turbine combined-cycle system increases thermal performance to the 60% level by increasing gas turbine operating temperature to 1430 C (2600 F) at a pressure ratio of 23 to 1. Although this represents a significant increase in operating temperature for the gas turbine, the potential for single digit NOx levels (based upon 15% O{sub 2}, in the exhaust) has been retained. The combined effect of performance increase and environmental control is achieved by an innovative closed loop steam cooling system which tightly integrates the gas turbine and steam turbine cycles. The {open_quotes}H{close_quotes} Gas Turbine Combined Cycle System meets the goals and objectives of the DOE Advanced Turbine System Program. The development and demonstration of this new system is being carried out as part of the Industrial/Government cooperative agreement under the ATS Program. This program will achieve first commercial operation of this new system before the end of the century.

  2. Studies on the Life Cycle

    African Journals Online (AJOL)

    Key words:Honeybees, Caste Differentiation, Larval Instar Determination, Life Cycle and Apiculture. ABSTRACT. 103. Ife Journal of Science vol. ... produce honey and beeswax (Seegeren et al., 1996 and Ojeleye, 1999). The dwarf ... Sri Lanka including Philippines and China is Apis. dorsataFabricius (1793) commonly ...

  3. Nuclear Fuel Cycle Introductory Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    The nuclear fuel cycle is a complex entity, with many stages and possibilities, encompassing natural resources, energy, science, commerce, and security, involving a host of nations around the world. This overview describes the process for generating nuclear power using fissionable nuclei.

  4. Business cycle synchronization in Europe

    DEFF Research Database (Denmark)

    Bergman, Ulf Michael; Jonung, Lars

    2011-01-01

    In this paper we study business cycle synchronization in the three Scandinavian countries Denmark, Norway and Sweden prior to, during and after the Scandinavian Currency Union 1873–1913. We find that the degree of synchronization tended to increase during the currency union, thus supporting earlier...

  5. Emissions from photovoltaic life cycles.

    Science.gov (United States)

    Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

    2008-03-15

    Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

  6. The Passive Aggressive Conflict Cycle

    Science.gov (United States)

    Whitson, Signe

    2013-01-01

    Understanding the Passive Aggressive Conflict Cycle (PACC) helps observers to be able to look beyond behavior and better understand what is occurring beneath the surface. This article presents a real-life example of a seemingly minor conflict between a teacher and child that elicited an apparent major overreaction by the adult. Also provided is a…

  7. Respiratory Mechanical and Cardiorespiratory Consequences of Cycling with Aerobars.

    Science.gov (United States)

    Charlton, Jesse M; Ramsook, Andrew H; Mitchell, Reid A; Hunt, Michael A; Puyat, Joseph H; Guenette, Jordan A

    2017-12-01

    Aerobars place a cyclist in a position where the trunk is flexed forward and the elbows are close to the midline of the body. This position is known to improve cycling aerodynamics and time trial race performance compared with upright cycling positions. However, the aggressive nature of this position may have important cardiorespiratory and metabolic consequences. The purpose of this investigation was to examine the respiratory mechanical, ventilatory, metabolic, and sensory consequences of cycling while using aerobars during laboratory-based cycling. Eleven endurance-trained male cyclists (age, 26 ± 9 yr; V˙O2peak, 55 ± 5 mL·kg·min) were recruited. Visit 1 consisted of an incremental cycling test to determine peak power output. Visit 2 consisted of 6-min bouts of constant load cycling at 70% of peak incremental power output in the aerobar position, drop position, and upright position while grasping the brake hoods. Metabolic and ventilatory responses were measured using a commercially available metabolic cart, and respiratory pressures were measured using an esophageal catheter. Cycling in the aerobar position significantly increased the work of breathing (Wb), power of breathing (Pb), minute ventilation, ventilatory equivalent for oxygen and carbon dioxide, and transdiaphragmatic pressure compared with the upright position. Increases in the Wb and Pb in the aerobars relative to the upright position were strongly correlated with the degree of thoracic restriction, measured as the shoulder-to-aerobar width ratio (Wb: r = 0.80, P = 0.01; Pb: r = 0.69, P = 0.04). Aerobars significantly increase the mechanical cost of breathing and leads to greater ventilatory inefficiency compared with upright cycling. Future work is needed to optimize aerobar width to minimize the respiratory mechanical consequences while optimizing aerodynamics.

  8. Dysmenorrhea, the menstrual cycle, and sleep.

    Science.gov (United States)

    Woosley, Julie A; Lichstein, Kenneth L

    2014-01-01

    This study examined the relationship between dysmenorrhea and insomnia, as well as variability in sleep across the menstrual cycle. Participants were 89 women, ages 18 to 24 (M = 18.63, SD = 0.93), who completed daily surveys for five weeks. On the second day of menses, they completed a questionnaire regarding dysmenorrhea. Participants having insomnia rated their dysmenorrhea as being more severe and causing more interference with daily activities than did participants without insomnia. Insomnia severity was directly associated with dysmenorrhea severity and interference. Sleep onset latency was longer and sleep efficiency was lower in participants with severe dysmenorrhea than in those with mild dysmenorrhea. Further, participants with mild dysmenorrhea reported significantly better sleep quality than did those having moderate or severe dysmenorrhea. Additionally, wake time after sleep onset was shortest and number of awakenings was lowest around the time of ovulation. Future research should examine whether treating dysmenorrhea or insomnia alone results in improvements in the other condition.

  9. Associations between Recreational and Commuter Cycling, Changes in Cycling, and Type 2 Diabetes Risk

    DEFF Research Database (Denmark)

    Rasmussen, Martin G; Grøntved, Anders; Blond, Kim

    2016-01-01

    of type 2 diabetes (T2D) in Danish adults from the Diet, Cancer and Health cohort study. METHODS AND FINDINGS: At baseline from 1993 to 1997, 24,623 men and 27,890 women from Denmark, 50-65 y of age and free of T2D and other chronic diseases, underwent a number of assessments, including completing...... a lifestyle questionnaire also addressing cycling habits. Approximately 5 y later, at a second examination, participants completed a new, updated lifestyle questionnaire. Cox regression was used to estimate hazard ratios (HRs) of incident T2D registered in the Danish National Diabetes Registry, according...... to recreational and commuter cycling and changes in cycling habits, with adjustment for a priori known T2D risk factors. During 743,245.4 person-years of follow-up (mean follow-up 14.2 y), 6,779 incident cases of T2D were documented. Multivariable adjusted HRs (95% confidence interval [CI]) were 1, 0.87 (0.82, 0...

  10. Patellar tracking during the gait cycle.

    Science.gov (United States)

    Abbas, Ghulam; Diss, Ceri

    2011-12-01

    To assess normal patellar tracking during walking using the 9-camera infrared system. Four men and 6 women aged 25 to 33 (mean, 29) years each performed 16 walking trials on one occasion. They had prominent patellae with minimal soft tissues (minimising skin artefacts), and their knees and lower limbs were normal and symmetrical. 12 retro-reflective markers (2.5 cm in diameter) were taped to anatomic landmarks of the lower body. Two additional markers (1.4 cm in diameter) were first placed on the medial and lateral points and then proximal and distal points of the patella. Patellar motion relative to the centre of the knee joint was defined as angles between the centre of the knee joint and the 2 sets of patellar markers (medial-lateral and proximal-distal). The mean, maximum, and minimum values of these angles in a standing position were recorded, as was patellar tracking during walking. The X, Y, and Z coordinates for each marker were smoothed out throughout the capturing time. A single gait cycle per trial was chosen for analysis. During walking, the centre of the knee joint and the patella did not move in unison, and the extent of separation was subject dependent. In 70% of the participants, the maximum angle between the centre of the knee joint and each set of markers occurred in the swing phase (0-43%) of the gait cycle. When analysing both sets of markers together, the percentage of participants became 60%. The extent of knee flexion was subject dependent. There was more medial-lateral motion (shift) of the patella than proximal-distal (tilt) motion during the gait cycle. These indicated that the maximum amount of patellar shift and tilt occurred in the swing and early stance phases of the gait cycle and that abnormal patellar motion can be detected if excessive shift or tilt occurs outside of these phases. Patella mal-tracking could be attributed to the position of the lower body segments rather than the absorption or generation of forces.

  11. Aging of Rejuvenated Asphalt Binders

    Directory of Open Access Journals (Sweden)

    Mojtaba Mohammadafzali

    2017-01-01

    Full Text Available An important concern that limits the RAP content in asphalt mixtures is the fact that the aged binder that is present in the RAP can cause premature cracking. Rejuvenators are frequently added to high RAP mixtures to enhance the properties of the binder. There is no existing method to predict the longevity of a rejuvenated asphalt. This study investigated the aging of rejuvenated binders and compared their durability with that of virgin asphalt. Various samples with different types and proportions of RAP, virgin binder, and rejuvenator were aged by RTFO and three cycles of PAV. DSR and BBR tests were conducted to examine the high-temperature and low-temperature rheological properties of binders. Results indicated that the type and dosage of the rejuvenator have a great influence on the aging rate and durability of the binder. Some rejuvenators make the binder age slower, while others accelerate aging. These observations confirm the importance of evaluating the long-term aging of recycled binders. For this purpose, critical PAV time was proposed as a measure of binder’s longevity.

  12. Combination of IVF and IVM in naturally cycling women

    DEFF Research Database (Denmark)

    Tang-Pedersen, Mikael; Westergaard, Lars Grabow; Erb, Karin

    2012-01-01

    This study investigated the combination of an unstimulated IVF cycle with in-vitro maturation (IVM) of additional immature cumulus-oocyte-complexes (COC) from the same cycle collected at the same time as the spontaneous preovulatory follicle. This could potentially improve rates of embryo transfer...... and pregnancy/live births compared with conventional unstimulated IVF treatment and at the same time eliminate the risk of ovarian hyperstimulation syndrome. This prospective trial included 77 women with regular menstrual cycles. Age at inclusion was between 20 and 37 years. Results showed a retrieval rate...... between endometrial factors and IVM oocytes together with unknown competence of IVM embryos is suspected. For some time, there has been an increasing interest in mild approaches for fertility treatment, in particular IVF. In-vitro maturation (IVM) of immature eggs outside the ovaries followed by IVF...

  13. Single-cell model of prokaryotic cell cycle.

    Science.gov (United States)

    Abner, Kristo; Aaviksaar, Tõnis; Adamberg, Kaarel; Vilu, Raivo

    2014-01-21

    One of the recognized prokaryotic cell cycle theories is Cooper-Helmstetter (CH) theory which relates start of DNA replication to particular (initiation) cell mass, cell growth and division. Different aspects of this theory have been extensively studied in the past. In the present study CH theory was applied at single cell level. Universal equations were derived for different cell parameters (cell mass and volume, surface area, DNA amount and content) depending on constructivist cell cycle parameters (unit mass, replication and division times, cell age, cell cycle duration) based on selected growth laws of cell mass (linear, exponential). The equations derived can be integrated into single-cell models for the analysis and design of bacterial cells. © 2013 Published by Elsevier Ltd.

  14. Modelling nutrient cycling in forest ecosystems; Modellering av naeringssyklus i skogoekosystemer

    Energy Technology Data Exchange (ETDEWEB)

    Kvindesland, Sheila H.S.B.

    1997-12-31

    Acid deposition`s threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway spruce forests, emphasizing the effects on soil chemical properties, soil solution chemistry and streamwater chemistry. It investigates the effects of different aged stands on nutrient cycling and sets up nutrient budgets of the base cations and nitrogen at two sites in Norway. It also selects, documents, calibrates, tests and improves nutrient cycling models for use in Norwegian forests. 84 refs., 44 figs., 46 tabs.

  15. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  16. Volatile earliest Triassic sulfur cycle

    DEFF Research Database (Denmark)

    Schobben, Martin; Stebbins, Alan; Algeo, Thomas J.

    2017-01-01

    Marine biodiversity decreases and ecosystem destruction during the end-Permian mass extinction (EPME) have been linked to widespread marine euxinic conditions. Changes in the biogeochemical sulfur cycle, microbial sulfate reduction (MSR), and marine dissolved sulfate concentrations during the Per...... of widespread euxinic conditions, posing a sustained threat to marine life during the Early Triassic.......Marine biodiversity decreases and ecosystem destruction during the end-Permian mass extinction (EPME) have been linked to widespread marine euxinic conditions. Changes in the biogeochemical sulfur cycle, microbial sulfate reduction (MSR), and marine dissolved sulfate concentrations during...... the Permian-Triassic transition can provide insights into the role of ocean chemistry change in the largest mass extinction in Earth history. In this study, we constrain marine dissolved sulfate concentrations using the MSR-trend method of Algeo et al. [Algeo, T.J., Luo, G.M., Song, H.Y., Lyons, T...

  17. Single-cycle nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Max-Planck-Institut fur Quantenoptik; Goulielmakis, E.; Schultze, M.; Hofstetter, M.; Yakovlev, V. S.; Gagnon, J.; Uiberacker, M.; Aquila, A. L.; gullikson, E. M.; attwood, D. T.; Kienberger, R.; Krausz, F.; Kleineberg, U.

    2008-11-05

    Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy {approx} 80 electron volts), containing {approx} 0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of {approx} 10{sup -6}. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time ({approx} 24 attoseconds).

  18. Fashion and death: Trends Cycles

    Directory of Open Access Journals (Sweden)

    Flavia Jakemiu Araújo Bortolon

    2016-12-01

    Full Text Available Fashion is composed of cycles subpostos trends that seek to eliminate the past for a new one, which makes it ephemeral and eternal at the same time. This study investigates how is the relationship between these cycles of trends over time, through a brief history of fashion, considering the theoretical rules of Simmel, Crane and Caldas. They will still be used concepts proposed by Agamben, such as: device, in order to classify the system of the fashion; contemporaneidade, to understand the action of that factor in relation to the time and profanation, to identify the capacity to maintain in the society. It is ended that the fashion, as well as the death, renews the society, it destroys and it creates the new, as a system naturalized artificially

  19. Cycle of conception endometrial biopsy.

    Science.gov (United States)

    Wentz, A C; Herbert, C M; Maxson, W S; Hill, G A; Pittaway, D E

    1986-08-01

    Although controversial, the diagnosis of luteal phase inadequacy and its therapy may improve reproductive outcome, but an endometrial biopsy in the cycle of conception (COC) might theoretically interrupt an intrauterine pregnancy. Fifty-four biopsies obtained in the COC were identified, and patient outcome was documented. Eleven (20%) of the 54 women who underwent COC biopsy did not deliver viable infants. Two patients had ectopic pregnancies, and nine had early abortions, including one whose biopsy specimen contained an early implantation site and another with a trisomy 16 fetus. Although COC endometrial biopsy did not appear to increase the incidence of fetal wastage, biopsy information provided no predictive information suggestive of ultimate pregnancy outcome. Because no useful information is gained from a COC biopsy, we recommend either that pregnancy be avoided or a sensitive pregnancy test be employed for detection in a cycle in which a biopsy is to be performed.

  20. Adverse childhood event experiences, fertility difficulties and menstrual cycle characteristics.

    Science.gov (United States)

    Jacobs, Marni B; Boynton-Jarrett, Renee D; Harville, Emily W

    2015-01-01

    Increased childhood adversity may be affect adult fertility, however, the mechanism through which this occurs is unclear. Menstrual cycle abnormalities are predictive of fertility difficulties, and stress influences menstrual cycle characteristics. Here, we assess whether adverse childhood experiences (ACEs) are associated with fertility difficulties and menstrual cycle dysregulation, offering a plausible mechanism for the link between lifetime stress and fertility. From April 2012 to February 2014, 742 pregnant and non-pregnant women aged 18-45 years residing in southeastern Louisiana provided information on childhood adversity and reproductive history. Associations between ACEs and fertility difficulties and menstrual cycle patterns were evaluated. As the number of ACEs increased, risk of fertility difficulties and amenorrhea increased (RR = 1.09, 95% CI 1.05-1.13 and RR = 1.07, 95% CI 1.04-1.10, respectively), while fecundability decreased [fecundability ratio (FR) = 0.97, 95% CI 0.95-1.00]. Compared to women with no adversity, women in the high adversity group were more likely to experience both infertility and amenorrhea (RR = 2.75, 95% CI 1.45-5.21 and RR = 2.54, 95% CI 1.52-4.25, respectively), and reduced fecundability (FR = 0.75, 95% CI 0.56-1.00). Although similar patterns were seen for menstrual cycle irregularity, associations were diminished. Associations did not materially change following adjustment for age, body mass index, race, education, smoking and income. Results are constrained by the self-report nature of the study and the limited generalizability of the study population. To our knowledge, this is the first study to present evidence of a link between childhood stressors, menstrual cycle disruption and fertility difficulties. The effect of childhood stress on fertility may be mediated through altered functioning of the HPA axis, acting to suppress fertility in response to less than optimal reproductive circumstances.

  1. Biomechanics of Counterweighted One-Legged Cycling.

    Science.gov (United States)

    Elmer, Steven J; McDaniel, John; Martin, James C

    2016-02-01

    One-legged cycling has served as a valuable research tool and as a training and rehabilitation modality. Biomechanics of one-legged cycling are unnatural because the individual must actively lift the leg during flexion, which can be difficult to coordinate and cause premature fatigue. We compared ankle, knee, and hip biomechanics between two-legged, one-legged, and counterweighted (11.64 kg) one-legged cycling. Ten cyclists performed two-legged (240 W), one-legged (120 W), and counterweighted one-legged (120 W) cycling (80 rpm). Pedal forces and limb kinematics were recorded to determine work during extension and flexion. During counterweighted one-legged cycling relative ankle dorsiflexion, knee flexion, and hip flexion work were less than one-legged but greater than two-legged cycling (all P cycling were greater than one-legged but less than two-legged cycling (all P cycling reduced but did not eliminate differences in joint flexion and extension actions between one- and two-legged cycling. Even with these differences, counterweighted one-legged cycling seemed to have advantages over one-legged cycling. These results, along with previous work highlighting physiological characteristics and training adaptations to counterweighted one-legged cycling, demonstrate that this exercise is a viable alternative to one-legged cycling.

  2. Biogeochemical Cycles in Degraded Lands

    Science.gov (United States)

    Davidson, Eric A.; Vieira, Ima Celia G.; ReisdeCarvalho, Claudio Jose; DeanedeAbreuSa, Tatiana; deSouzaMoutinho, Paulo R.; Figueiredo, Ricardo O.; Stone, Thomas A.

    2004-01-01

    The objectives of this project were to define and describe the types of landscapes that fall under the broad category of "degraded lands" and to study biogeochemical cycles across this range of degradation found in secondary forests. We define degraded land as that which has lost part of its capacity of renovation of a productive ecosystem, either in the context of agroecosystems or as native communities of vegetation. This definition of degradation permits evaluation of biogeochemical constraints to future land uses.

  3. Linked Partitions and Linked Cycles

    OpenAIRE

    Chen, William Y. C.; Wu, Susan Y. J.; Yan, Catherine H.

    2006-01-01

    The notion of noncrossing linked partition arose from the study of certain transforms in free probability theory. It is known that the number of noncrossing linked partitions of [n+1] is equal to the n-th large Schroder number $r_n$, which counts the number of Schroder paths. In this paper we give a bijective proof of this result. Then we introduce the structures of linked partitions and linked cycles. We present various combinatorial properties of noncrossing linked partitions, linked partit...

  4. Low frequency split cycle cryocooler

    Science.gov (United States)

    Bian, S. X.; Zhang, Y. D.; Wan, W. W.; Wang, L.; Hu, Q. C.

    1985-01-01

    A split cycle Stirling cryocooler with two different drive motors and operating at a low drive frequency can have high thermodynamic efficiency. The temperature of the cold end of the cryocooler varies with drive frequency, voltage of the input electrical power and initial charge pressure values. The cryocooler operating at 8 Hz can provide 7 watts of refrigeration at 77 K for 230 watts of electrical input power.

  5. Control of locomotor cycle durations.

    Science.gov (United States)

    Yakovenko, S; McCrea, D A; Stecina, K; Prochazka, A

    2005-08-01

    In intact animals and humans, increases in locomotor speed are usually associated with decreases in step cycle duration. Most data indicate that the locomotor central pattern generator (CPG) shortens cycle duration mainly by shortening the durations of extensor rather than flexor phases of the step cycle. Here we report that in fictive locomotion elicited by electrical stimulation of the midbrain locomotor region (MLR) in the cat, spontaneous variations in cycle duration were due more to changes in flexor rather than extensor phase durations in 22 of 31 experiments. The locomotor CPG is therefore not inherently extensor- or flexor-biased. We coined the term "dominant" to designate the phase (flexion or extension) showing the larger variation. In a simple half-center oscillator model, experimental phase duration plots were fitted well by adjusting two parameters that corresponded to background drive ("bias") and sensitivity ("gain") of the oscillator's timing elements. By analogy we argue that variations in background drive to the neural timing elements of the CPG could produce larger variations in phase duration in the half-center receiving the lower background drive, i.e., background drive may determine which half-center is dominant. The fact that data from normal cats were also fitted well by the model indicates that sensory input and central drive combine to determine locomotor phase durations. We conclude that there is a considerable flexibility in the control of phase durations in MLR-induced fictive locomotion. We posit that this may be explained by changes in background excitation of neural timing elements in the locomotor CPG.

  6. Technology cycles and technology revolutions

    Energy Technology Data Exchange (ETDEWEB)

    Paganetto, Luigi; Scandizzo, Pasquale Lucio

    2010-09-15

    Technological cycles have been characterized as the basis of long and continuous periods economic growth through sustained changes in total factor productivity. While this hypothesis is in part consistent with several theories of growth, the sheer magnitude and length of the economic revolutions experienced by humankind seems to indicate surmise that more attention should be given to the origin of major technological and economic changes, with reference to one crucial question: role of production and use of energy in economic development.

  7. Economic Comparisons Between an Even-Aged and an Uneven-Aged Loblolly Pine Silvicultural System

    OpenAIRE

    Cafferata, Michael J.S.

    1997-01-01

    This study compares financially optimal uneven-aged and even-aged silvicultural regimes of loblolly pine (Pinus Taeda). Uneven-aged regimes which maximize net present value (NPV) are found by quantifying the effects of diameter distribution (Q factor), maximum diameter, cutting cycle, and residual basal area on NPV. For the benchmark inputs, the regime yielding the highest NPV had a maximum diameter of 12 inches, residual basal area of 45 ft2/acre, and a cutting cyc...

  8. [Changes in bone mineral density of postmenopausal women in relation to the menstrual cycle length].

    Science.gov (United States)

    Enchev, E; Dimitrakova, E

    2010-01-01

    There is a strong relationship between the age of menarche, the length of the menstrual cycle and menstrual bleeding and fracture risk in the postmenopausal period. Evaluation of the menstrual cycle length and lumbar bone mineral density in postmenopausal women. We investigated three groups of postmenopausal women (each - n = 50). The first group included women with menstrual duration of 27 days during reproductive age, the second group included postmenopausal women with menstrual duration of 28 days during the reproductive age, and the third group consisted of postmenopausal women with menstrual duration of 30 days during reproductive age. The average age of women was 58.80 +/- 0.94 y. in the first group, 60.36 +/- 5.12 y. in the second group and -61.84 +/- 0.80 y. in the third group. Age, age of menarche, number of childbirths, length of the menstrual cycle and menstrual bleeding, and lumbar bone density were assessed and registered for each woman. We used DXA in a anterior-posterior projection to assess the bone density of the lumbar spine; the obtained results are shown in gram/cm2. The women from the third group, with average menstrual cycle length of 30 days, reach menopause at a significantly later age, have longer menstrual cycle and shorter menstrual bleeding, and higher lumbar spine bone density, compared to the other two groups. The data from our research show that women with anamnesis for average normal menstrual cycle length of 30 days reach menopausal period at a significantly later age, have shorter menstrual bleeding, and higher lumbar spine bone density compared to those with shorter menstrual cycle duration (27 and 28 days).

  9. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2009-12-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  10. Repeated Maxima of Sunspot Cycles

    Science.gov (United States)

    Krivodubskij, V.

    2015-12-01

    The explanation for the observed phenomenon of repeated maxima of sunspot cycles is proposed. Key roles in the proposed scenarioplay two tides of toroidal field from the lower base of the solar convection zone (SCZ) to the surface. Deep toroidal field is excited due to Ω-effectnear the bottom of the SCZ at the beginning of the cycle. Then this field is transported to the surface due to combined acting of magnetic buoyancy,magnetic ∇ρ-flow and turbulent diamagnetism in the equatorial domain. Over time the magnetic fragments can be seen as bipolar spots in themiddle latitudes in the "royal zone". This first wave of toroidal field, which is directed up, gives the main maximum activity spots. However, theunderlying toroidal field in the high-latitude polar domains at the beginning of the cycle is blocked by directed downward magnetic∇ρ-pumping and turbulent diamagnetism. Directed to the equator deep meridional flow replaces this field to the low latitudes (the equatorialdomain) during about 1 - 2 years. After that the turn of floating this "retarded" field to surface (second tide of toroidal field). Coming to the surfaceat low latitudes this second portion of toroidal field leads to second sunspot maximum.

  11. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert

    2007-04-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 26 cost modules—24 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, and high-level waste.

  12. Digital Daily Cycles of Individuals

    Directory of Open Access Journals (Sweden)

    Talayeh eAledavood

    2015-10-01

    Full Text Available Humans, like almost all animals, are phase-locked to the diurnal cycle. Most of us sleep at night and are active through the day. Because we have evolved to function with this cycle, the circadian rhythm is deeply ingrained and even detectable at the biochemical level. However, within the broader day-night pattern, there are individual differences: e.g., some of us are intrinsically morning-active, while others prefer evenings. In this article, we look at digital daily cycles: circadian patterns of activity viewed through the lens of auto-recorded data of communication and online activity. We begin at the aggregate level, discuss earlier results, and illustrate differences between population-level daily rhythms in different media. Then we move on to the individual level, and show that there is a strong individual-level variation beyond averages: individuals typically have their distinctive daily pattern that persists in time. We conclude by discussing the driving forces behind these signature daily patterns, from personal traits (morningness/eveningness to variation in activity level and external constraints, and outline possibilities for future research.

  13. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2008-03-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  14. The parenting cycle of deployment.

    Science.gov (United States)

    DeVoe, Ellen R; Ross, Abigail

    2012-02-01

    Parents of dependent children comprise approximately 42% of Active Duty and National Guard/Reserve military members serving in Operation Iraqi Freedom/Operation Enduring Freedom. Recent estimates indicate that more than two million children have experienced parental deployment since the terrorist attacks on September 11, 2001. This article seeks to characterize the impact of the deployment life cycle on parenting roles among service members and at-home partners/caregivers of dependent children. Specifically, a new conceptual framework is presented for considering the ways in which parenting and co-parenting processes are affected by the demands and transitions inherent in contemporary deployment to a war zone. Although the phase-based emotional cycle of deployment continues to offer an instructive description of the broad challenges faced by military couples, a parenting cycle of deployment model shifts the perspective to the critical and largely ignored processes of parenting in the context of deployment and war, and to the realities faced by parents serving in the U.S. military. Implications for prevention, intervention, and future research related to military families are addressed.

  15. Soleus stretch reflex during cycling.

    Science.gov (United States)

    Grey, M J; Pierce, C W; Milner, T E; Sinkjaer, T

    2001-01-01

    The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions during the crank cycle, producing ankle dorsiflexion perturbations of similar trajectory. The stretch reflex was greatest during the power phase of the crank cycle and was decreased to the level of background EMG during recovery. Matched perturbations were induced under static conditions at the same crank angle and background soleus EMG as recorded during the power phase of active pedaling. The magnitude of the stretch reflex was not statistically different from that during the static condition throughout the power phase of the movement. The results of this study indicate that the stretch reflex is not depressed during active cycling as has been shown with the H-reflex. This lack of depression may reflect a decreased susceptibility of the stretch reflex to inhibition, possibly originating from presynaptic mechanisms.

  16. Perceived environmental correlates of cycling for transport among adults in five regions of Europe.

    Science.gov (United States)

    Mertens, L; Compernolle, S; Gheysen, F; Deforche, B; Brug, J; Mackenbach, J D; Lakerveld, J; Oppert, J-M; Feuillet, T; Glonti, K; Bárdos, H; De Bourdeaudhuij, I

    2016-01-01

    Regular cycling for transport is an important potential contributor to daily physical activity among adults. Characteristics of the physical environment are likely to influence cycling for transport. The current study investigated associations between perceived physical environmental neighbourhood factors and adults' cycling for transport across five urban regions across Europe, and whether such associations were moderated by age, gender, education and urban region. A total of 4,612 adults from five European regions provided information about their transport-related cycling and their neighbourhood physical environmental perceptions in an online survey. Hurdle models adjusted for the clustering within neighbourhoods were performed to estimate associations between perceived physical environmental neighbourhood factors and odds of engaging in cycling for transport and minutes of cycling for transport per week. Inhabitants of neighbourhoods that were perceived to be polluted, having better street connectivity, having lower traffic speed levels and being less pleasant to walk or cycle in had higher levels of cycling for transport. Moderation analyses revealed only one interaction effect by gender. This study indicates that cycling for transport is associated with a number of perceived physical environmental neighbourhood factors across five urban regions across Europe. Our results indicated that the majority of the outcomes identified were valid for all subgroups of age, gender, education and across regions in the countries included in the study. © 2016 World Obesity.

  17. Does whole-body cryotherapy improve vertical jump recovery following a high-intensity exercise bout?

    Science.gov (United States)

    Vieira, Amilton; Bottaro, Martim; Ferreira-Junior, Joao B; Vieira, Carlos; Cleto, Vitor A; Cadore, Eduardo L; Simões, Herbert G; Carmo, Jake Do; Brown, Lee E

    2015-01-01

    Whole-body cryotherapy (WBC) has been used as a recovery strategy following different sports activities. Thus, the aim of the study reported here was to examine the effect of WBC on vertical jump recovery following a high-intensity exercise (HIE) bout. Twelve trained men (mean ± standard deviation age = 23.9±5.9 years) were randomly exposed to two different conditions separated by 7 days: 1) WBC (3 minutes of WBC at -110°C immediately after the HIE) and 2) control (CON; no WBC after the HIE). The HIE consisted of six sets of ten repetitions of knee extensions at 60° · s(-1) concentric and 180° · s(-1) eccentric on an isokinetic dynamometer. The vertical jump test was used to evaluate the influence of HIE on lower extremity muscular performance. The vertical jump was performed on a force platform before HIE (T1) and 30 minutes after (T2) the WBC and CON conditions. As a result of HIE, jump height, muscle power, and maximal velocity (Vmax) had significant decreases between T1 and T2, however no significance was found between the WBC and CON conditions. The results indicate that one session of WBC had no effect on vertical jump following an HIE compared with a CON condition. WBC may not improve muscle-function (dependent on stretch-shortening cycle) recovery in very short periods (ie, 30 minutes) following HIE.

  18. The Effect of Water Temperature during Cold-Water Immersion on Recovery from Exercise-Induced Muscle Damage.

    Science.gov (United States)

    Vieira, A; Siqueira, A F; Ferreira-Junior, J B; do Carmo, J; Durigan, J L Q; Blazevich, A; Bottaro, M

    2016-11-01

    This study investigated the effects of 5 and 15°C cold-water immersion on recovery from exercise resulting in exercise-induced muscle damage. 42 college-aged men performed 5×20 drop-jumps and were randomly allocated into one of 3 groups: (1) 5°C; (2) 15°C; or (3) control. After exercise, individuals from the cold-water immersion groups had their lower limbs immerged in iced water for 20 min. Isometric knee extensor torque, countermovement jump, muscle soreness, and creatine kinase were measured before, immediately after, 24, 48, 72, 96 and 168 h post-exercise. There was no between-group difference in isometric strength recovery (p=0.73). However, countermovement jump recovered quicker in cold-water immersion groups compared to control group (pcold-water immersion promote recovery of stretch-shortening cycle performance, but not influence the recovery of maximal contractile force. Immersion at warmer temperature may be more effective than colder temperatures promoting recovery from strenuous exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  19. BUSINESS CYCLES, ELECTORAL CYCLES. TOWARD A THEORETICAL FRAME OF INTERACTION

    Directory of Open Access Journals (Sweden)

    BOGDAN-LUCIAN DOSPINESCU

    2015-06-01

    Full Text Available The idea of cyclical movement of a system: be it political, economic, institutional, is one of the constants of critical thinking. In this sense, there is a natural cyclic movement that cannot be avoided (only amplified or diminished and is connected with the nature of these systems. The economy follows a cyclical movement; a period of growth follows a period of decline, and so on. So does popularity for political parties or leaders. In this paper, I explore the links between the business cycles and electoral cycles. For this purpose, I introduce the concept of electoral perception cycles. My hypothesis is that popularity of political parties and leaders follow a cyclical evolution, both on short and long term. I show how perception cycles can impact the “political business cycle theory”. There is great interest in political science literature for the factors that influence the fluctuations in Presidents’ popularity, especially from United States. However, very little has been said about Romania’s case. I investigate the hypothesis of electoral perception cycles looking at the popularity of former president Traian Basescu, over his two terms. The variable used to measure popularity is favorability, measured in national surveys, done face to face, on representative samplez, of around 1000 subjects. I’ve correlated the fluctuations in favorability over time, with key public events or political decisions taken by Traian Băsescu. The main findings are as follows. Firstly, there are significant short term fluctuations (short term perception cycles and they are correlated with major events on the agenda. I would point the following key moments: 1. The referendum for dismissal of the President in May 2007 – Traian Băsescu’s favorability increased by 7 percentage points; 2. The referendum for unicameral Parliament with 300 MPs in the fall of 2009. Coupled with victory in the presidential election, it lead to an increase of 10 percentage

  20. Quantification of Underestimation of Physical Activity During Cycling to School When Using Accelerometry

    DEFF Research Database (Denmark)

    Tarp, Jakob; Andersen, Lars B; Østergaard, Lars

    2015-01-01

    Background: Cycling to and from school is an important source of physical activity (PA) in youth but it is not captured by the dominant objective method to quantify PA. The aim of this study was to quantify the underestimation of objectively assessed PA caused by cycling when using accelerometry....... Methods: Participants were 20 children aged 11-14 years from a randomized controlled trial performed in 2011. Physical activity was assessed by accelerometry with the addition of heart rate monitoring during cycling to school. Global positioning system (GPS) was used to identify periods of cycling...... to school. Results: Mean (95% CI) minutes of moderate-to-vigorous physical activity (MVPA) during round-trip commutes was 10.8 (7.1 - 16.6). Each kilometre of cycling meant an underestimation of 9314 (95%CI: 7719 - 11238) counts and 2.7 (95%CI: 2.1 - 3.5) minutes of MVPA. Adjusting for cycling to school...

  1. Intensity versus duration of cycling, impact on all-cause and coronary heart disease mortality

    DEFF Research Database (Denmark)

    Schnohr, Peter; Marott, Jacob L; Jensen, Jan S

    2012-01-01

    the impact of intensity versus duration of cycling on all-cause and coronary heart disease mortality. Design: Relative intensity and duration of cycling were recorded in 5106 apparently healthy men and women aged 21-90 years drawn from the general population of Copenhagen, and followed for an average of 18...... years. Total number of deaths during follow-up was 1172, of these 146 were coronary heart disease deaths. For both sexes we found a significant inverse association between cycling intensity and risk of all-cause and coronary heart disease death, but only a weak association with cycling duration......: Our findings indicate that the relative intensity, and not the duration of cycling, is of more importance in relation to all-cause and coronary heart disease mortality. Thus our general recommendations to all adults would be that brisk cycling is preferable to slow....

  2. Drivers of cycling mode-share: analysis of danes travel behavior 1996-2013

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Mulalic, Ismir; Christiansen, Hjalmar

    2016-01-01

    Denmark, as Europes second cycling nation after the Netherlands, has a cycling mode share of around 15% of all trips. Cycling was decreasing slowly through the 1990s into the 2000s, which inspired substantial investments and promotional efforts to reverse the trend. This paper uses Danish micro......-level travel survey data series from 1996 through 2013 to analyze the trend in cycling as main or access mode, as well as the significance of background variables representing key spatial and societal trends. The analysis confirms that the general trend in cycling from 1996 to 2013 was negative irrespective...... of statistical control for socio-economics, ageing, location, urban density, and weather. Results points to an increasing significance of population density over time as well as changes to the effect of location vis-a-vis the largest urban centers. The difference in cycling between central areas and more...

  3. Circadian Rhythms, Sleep, and Disorders of Aging

    OpenAIRE

    Mattis, Joanna; Sehgal, Amita

    2016-01-01

    Sleep:wake cycles are known to be disrupted in people with neurodegenerative disorders. These findings are now supported by data from animal models for some of these disorders, raising the question of whether the disrupted sleep/circadian regulation contributes to the loss of neural function. As circadian rhythms and sleep consolidation also break down with normal aging, changes in these may be part of what makes aging a risk factor for disorders like Alzheimer's disease. Mechanisms underlyin...

  4. Menstrual Cycle Hormone Changes in Women Traversing Menopause: Study of Women's Health Across the Nation.

    Science.gov (United States)

    Santoro, Nanette; Crawford, Sybil L; El Khoudary, Samar R; Allshouse, Amanda A; Burnett-Bowie, Sherri-Ann; Finkelstein, Joel; Derby, Carol; Matthews, Karen; Kravitz, Howard M; Harlow, Sioban D; Greendale, Gail A; Gold, Ellen B; Kazlauskaite, Rasa; McConnell, Dan; Neal-Perry, Genevieve; Pavlovic, Jelena; Randolph, John; Weiss, Gerson; Chen, Hsiang-Yu; Lasley, Bill

    2017-07-01

    Menstrual cycle hormone patterns in women approaching menopause are inadequately studied. To describe day-to-day menstrual cycle hormones in women as they approach menopause from the Study of Women's Health Across the Nation Daily Hormone Study (DHS). DHS enrollees collected daily urine for one entire menstrual cycle or up to 50 days, whichever came first, annually, up to the final menstrual period (FMP) or for up to 10 years. Seven sites across the United States. A total of 511 premenopausal or early perimenopausal women at enrollment, within 10 years before menopause. Time-to-FMP measurement. Evidence of luteal activity (ELA), determined using objective algorithms. Menstrual cycle/segment length; whole cycle, and segment integrated urinary luteinizing hormone, follicle-stimulating hormone, estrone conjugates, and pregnanediol glucuronide (Pdg) for each year, organized around the FMP. Mean menstrual cycle length was remarkably preserved at 26 to 27 days in ELA cycles; non-ELA cycles had greater variability. The percentage of cycles that were ELA remained high until 5 years before the FMP (87.9%); only 22.8% of cycles within 1 year of the FMP were ELA. Whole cycle hormones remained relatively stable up to 3 years before the FMP, when gonadotropins began to increase. Pdg excretion declined slowly with progress to the FMP, but Pdg patterns of ELA cycles remained distinguishable from non-ELA. Menstrual cycle hormone patterns in perimenopausal women resemble those of midreproductive-aged women until 5 years before menopause, and presumably ovulatory cycles retain a potentially fertile pattern up to the end of reproductive life.

  5. Menstrual-cycle dependence of breast parenchyma elasticity: estimation with magnetic resonance elastography of breast tissue during the menstrual cycle.

    Science.gov (United States)

    Lorenzen, Jörn; Sinkus, Ralph; Biesterfeldt, Maike; Adam, Gerhard

    2003-04-01

    Magnetic resonance elastography (MRE) is a promising diagnostic method that produces images with a contrast proportional to the elasticity of the tissue. This study investigated using MRE the dependence of breast tissue elasticity from the menstrual cycle of healthy volunteers. Five volunteers (age 26-36) without breast disease and contraceptive medication were examined once weekly over 2 menstrual cycles. Examinations were performed with a 1.5 T magnet (ACS-NT, Philips Medical Systems, Best, The Netherlands). Low-frequency mechanical waves (65 Hz) were transmitted into the tissue by an oscillator. By means of a motion-sensitive spin-echo sequence, mechanical waves were displayed within the phase of the MR image and phase images were used to reconstruct the local distribution of elasticity. The elasticity of fibroglandular tissue and adipose breast tissue was analyzed individually, and the median and mean values of elasticity over the menstrual cycle were determined. All volunteers presented a repeating pattern concerning the elasticity over the 2 cycles. After 5 days of the onset of menses, the median value of elasticity for fibroglandular adipose tissue declined significantly by -29% (P = 0.010). After the second week of the cycle, fibroglandular tissue showed again an increase in elasticity (P = 0.028). The highest median values of elasticity were obtained during days 11 to 23 with an increase of up to 35%. For adipose tissue, only a slight and not significant variation of elasticity during the menstrual cycle was determined. MRE is able to measure a dependence of tissue elasticity on the menstrual cycle.

  6. Dose–response associations between cycling activity and risk of hypertension in regular cyclists: The UK Cycling for Health Study

    Science.gov (United States)

    Hollingworth, M; Harper, A; Hamer, M

    2015-01-01

    Most population studies on physical activity and health have involved largely inactive men and women, thus making it difficult to infer if health benefits occur at exercise levels above the current minimum guidelines. The aim was to examine associations between cycling volume and classical cardiovascular risk markers, including hypertension and hypercholesterolemia, in a population sample of habitual cyclists. A nationwide sample comprising 6949 men and women (aged 47.6 years on average) completed questions about their cycling levels, demographics and health. Nearly the entire sample (96.3%) achieved the current minimum physical activity recommendation through cycling alone. There was a dose–response association between cycling volume and risk of diagnosed hypertension (P-trend =0.001), with odds ratios of 0.98 (95% confidence interval (CI), 0.80–1.21), 0.86 (0.70, 1.06), 0.67 (95% CI, 0.53–0.83) across categories of 23–40, 40–61 and >61 metabolic equivalent hours/week (MET-h/week) compared with cycling volume and other risk factors including BMI and hypercholesterolemia. In summary, results from a population sample of cyclists suggest that additional cardiovascular health benefits can be achieved beyond the current minimum physical activity recommendation. PMID:25273856

  7. Disability and Psychosocial Development in Old Age.

    Science.gov (United States)

    Kivnick, Helen Q.

    1985-01-01

    Explores the impact of disability on psychosocial development in old age and vice versa. Considers both the ways that physiological disabilities influence normative psychosocial development in the final stage of the life cycle and the kinds of influence psychosocial factors may have on the older person's experience of disability. (Author/BL)

  8. Biogeochemical cycles: Interactions in global metabolism

    Science.gov (United States)

    Moore, B., III; Morowitz, H.; Dastoor, M. N.

    1984-01-01

    A science that chooses the globe as it fundamental biogeophysical unit forces extraordinary conceptual difficulties. The roles of energy flow, matter cycles, carbon cycle, air pollution, global effects, air water interactions are discussed.

  9. Introducing Mendelian Genetics Through a Learning Cycle.

    Science.gov (United States)

    Lawson, Anton E.

    1996-01-01

    Presents activities that use the learning cycle to engage students in meaningful inquiries in the study of Mendelian genetics. Includes content-related background and teaching tips for each phase of the learning cycle. (JRH)

  10. Sprint cycling training improves intermittent run performance

    Directory of Open Access Journals (Sweden)

    Hardaway Chun-Kwan Chan

    2018-01-01

    Conclusions: Sprint cycling significantly improved intermittent run performance, VO2max and peak power output at VO2max. Sprint cycling training is suitable for intermittent sports athletes but separate speed and COD training should be included.

  11. Non-MTC gait cycles: An adaptive toe trajectory control strategy in older adults.

    Science.gov (United States)

    Santhiranayagam, Braveena K; Sparrow, W A; Lai, Daniel T H; Begg, Rezaul K

    2017-03-01

    Minimum-toe-clearance (MTC) above the walking surface is a critical representation of toe-trajectory control due to its association with tripping risk. Not all gait cycles exhibit a clearly defined MTC within the swing phase but there have been few previous accounts of the biomechanical characteristics of non-MTC gait cycles. The present report investigated the within-subject non-MTC gait cycle characteristics of 15 older adults (mean 73.1 years) and 15 young controls (mean 26.1 years). Participants performed the following tasks on a motorized treadmill: preferred speed walking, dual task walking (carrying a glass of water) and a dual-task speed-matched control. Toe position-time coordinates were acquired using a 3 dimensional motion capture system. When MTC was present, toe height at MTC (MTCheight) was extracted. The proportion of non-MTC gait cycles was computed for the age groups and individuals. For non-MTC gait cycles an 'indicative' toe height at the individual's average swing phase time (MTCtime) for observed MTC cycles was averaged across multiple non-MTC gait cycles. In preferred-speed walking Young demonstrated 2.9% non-MTC gait cycles and Older 18.7%. In constrained walking conditions both groups increased non-MTC gait cycles and some older adults revealed over 90%, confirming non-MTC gait cycles as an ageing-related phenomenon in lower limb trajectory control. For all participants median indicative toe-height on non-MTC gait cycles was greater than median MTCheight. This result suggests that eliminating the biomechanically hazardous MTC event by adopting more of the higher-clearance non-MTC gait cycles, is adaptive in reducing the likelihood of toe-ground contact. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Feasibility and safety of in-bed cycling for physical rehabilitation in the intensive care unit.

    Science.gov (United States)

    Kho, Michelle E; Martin, Robert A; Toonstra, Amy L; Zanni, Jennifer M; Mantheiy, Earl C; Nelliot, Archana; Needham, Dale M

    2015-12-01

    The purpose was to evaluate the feasibility and safety of in-bed cycle ergometry as part of routine intensive care unit (ICU) physical therapist (PT) practice. Between July 1, 2010, and December 31, 2011, we prospectively identified all patients admitted to a 16-bed medical ICU receiving cycling by a PT, prospectively collected data on 12 different potential safety events, and retrospectively conducted a chart review to obtain specific details of each cycling session. Six hundred eighty-eight patients received PT interventions, and 181 (26%) received a total of 541 cycling sessions (median [interquartile range {IQR}] cycling sessions per patient, 2 [1-4]). Patients' mean (SD) age was 57 (17) years, and 103 (57%) were male. The median (IQR) time from medical ICU admission to first PT intervention and first cycling session was 2 (1-4) and 4 (2-6) days, respectively, with a median (IQR) cycling session duration of 25 (18-30) minutes. On cycling days, the proportion of patients receiving mechanical ventilation, vasopressor infusions, and continuous renal replacement therapy was 80%, 8%, and 7%, respectively. A single safety event occurred, yielding a 0.2% event rate (95% upper confidence limit, 1.0%). Use of in-bed cycling as part of routine PT interventions in ICU patients is feasible and appears safe. Further study of the potential benefits of early in-bed cycling is needed. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Terminology gap in hydrological cycle

    Science.gov (United States)

    Zhuo, Lu; Han, Dawei

    2016-04-01

    Water is central to life on Earth. People have been trying to understand how water moves in the hydrosphere throughout the human history. In the 9th century BC, the famous Greek poet Homer described the hydrological cycle in Iliad as "okeanos whose stream bends back in a circle" with a belief that rivers are ocean-fed from subterranean seas. Later, Aristotle (4th century BC) claimed that most of the water came from underground caverns in which air was transformed into water. It was only until 1674, French scientist Perrault developed the correct concept of the water cycle. In modern times, scientists are interested in understanding the individual processes of the hydrological cycle with a keen focus on runoff which supplies water to rivers, lakes, and oceans. Currently, the prevailing concepts on runoff processes include 'infiltration excess runoff' and 'saturation excess runoff'. However, there is no term to describe another major runoff due to the excess beyond the soil water holding capacity (i.e., the field capacity). We argue that a new term should be introduced to fill this gap, and it could be called 'holding excess runoff' which is compatible with the convention. This new term is significant in correcting a half-century misnomer where 'holding excess runoff' has been incorrectly named as 'saturation excess runoff', which was introduced by the Xinanjiang model in China in 1960s. Similar concept has been adopted in many well-known hydrological models such as PDM and HBV in which the saturation refers to the field capacity. The term 'holding excess runoff' resolves such a common confusion in the hydrological community.

  14. Multipartite graph decomposition: cycles and closed trails

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Billington

    2004-11-01

    Full Text Available This paper surveys results on cycle decompositions of complete multipartite graphs (where the parts are not all of size 1, so the graph is not K_n , in the case that the cycle lengths are “small”. Cycles up to length n are considered, when the complete multipartite graph has n parts, but not hamilton cycles. Properties which the decompositions may have, such as being gregarious, are also mentioned.

  15. Bicycle infrastructure: can good design encourage cycling?

    OpenAIRE

    Angela Hull; Craig O’Holleran

    2014-01-01

    This research posits the question that good design of the bicycle infrastructure in a city will encourage more people to cycle. Research is carried out to compare the cycle infrastructure in selected European cities against an adapted Level of Service concept using accompanied ride-alongs. The literature review on the factors that encourage/dissuade cycle use suggests that it is the potential rider’s perceptions on the safety of cycling in their neighbourhood that is the deciding feature. Mor...

  16. Business Cycle Dependent Unemployment Insurance

    DEFF Research Database (Denmark)

    Andersen, Torben M.; Svarer, Michael

    The consequences of business cycle contingencies in unemployment insurance systems are considered in a search-matching model allowing for shifts between "good" and "bad" states of nature. We show that not only is there an insurance argument for such contingencies, but there may also be an incentive...... argument. Since benefits may be less distortionary in a recession than a boom, it follows that counter-cyclical benefits reduce average distortions compared to state independent benefits. We show that optimal (utilitarian) benefits are counter-cyclical and may reduce the structural (average) unemployment...... rate, although the variability of unemployment may increase....

  17. Introducing Life Cycle Impact Assessment

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky; Huijbregts, Mark AJ

    2015-01-01

    methodology projects and presents the international scientific discussions and methodological consensus attempts in consecutive working groups under the auspices of the Society of Environmental Toxicology and Chemistry (SETAC) as well as the UNEP/ SETAC Life Cycle Initiative, and the (almost) parallel...... standardisation activities under the International Organisation for Standardisation (ISO). A brief introduction is given on the purpose and structure of LCIA. As a common background for the 11 chapters dealing with the characterisation modelling of the most common impact categories, the chapter concludes...

  18. Climate and the Carbon Cycle

    Science.gov (United States)

    Manley, Jim

    2017-04-01

    Climate and the Carbon Cycle EOS3a Science in tomorrow's classroom Students, like too much of the American public, are largely unaware or apathetic to the changes in world climate and the impact that these changes have for life on Earth. A study conducted by Michigan State University and published in 2011 by Science Daily titled 'What carbon cycle? College students lack scientific literacy, study finds'. This study relates how 'most college students in the United States do not grasp the scientific basis of the carbon cycle - an essential skill in understanding the causes and consequences of climate change.' The study authors call for a new approach to teaching about climate. What if teachers better understood vital components of Earth's climate system and were able to impart his understanding to their students? What if students based their responses to the information taught not on emotion, but on a deeper understanding of the forces driving climate change, their analysis of the scientific evidence and in the context of earth system science? As a Middle School science teacher, I have been given the opportunity to use a new curriculum within TERC's EarthLabs collection, Climate and the Carbon Cycle, to awaken those brains and assist my students in making personal lifestyle choices based on what they had learned. In addition, with support from TERC and The University of Texas Institute for Geophysics I joined others to begin training other teachers on how to implement this curriculum in their classrooms to expose their students to our changing climate. Through my poster, I will give you (1) a glimpse into the challenges faced by today's science teachers in communicating the complicated, but ever-deepening understanding of the linkages between natural and human-driven factors on climate; (2) introduce you to a new module in the EarthLabs curriculum designed to expose teachers and students to global scientific climate data and instrumentation; and (3) illustrate how

  19. Nitrogen Cycle Ninja, A Teaching Exercise.

    Science.gov (United States)

    Raun, William R.; And Others

    1997-01-01

    Assesses the effectiveness of using pop quizzes and rewards to improve student retention of the nitrogen cycle. Students able to diagram the N cycle on pop quizzes were rewarded with special cards that included the N cycle. These cards could then be used on subsequent tests in place of memory alone. Six of 11 students tested three months later…

  20. Transcriptional regulation of the cell cycle

    NARCIS (Netherlands)

    Stahl, M.

    2006-01-01

    Transcriptional regulators play an important role during cell cycle progression. A subset of these even seems to have a critical function in regulating cell cycle transitions. In this thesis, I have addressed the importance of transcriptional control in the regulation of cell cycle progression, in

  1. "Constructing" the Cell Cycle in 3D

    Science.gov (United States)

    Koc, Isil; Turan, Merve

    2012-01-01

    The cycle of duplication and division, known as the "cell cycle," is the essential mechanism by which all living organisms reproduce. This activity allows students to develop an understanding of the main events that occur during the typical eukaryotic cell cycle mostly in the process of mitotic phase that divides the duplicated genetic material…

  2. The next generation of revenue cycle management.

    Science.gov (United States)

    Hammer, David C

    2007-07-01

    The revenue cycle management environment is dynamic. Revenue cycle leaders are now responsible for additional functional areas and have to deal with new financing arrangements that expose the organization to greater financial risk. Financial managers can use key performance indicators and the suggested practice processes checklist to determine whether their revenue cycle operations are in good shape or need shaping up.

  3. Does It Have a Life Cycle?

    Science.gov (United States)

    Keeley, Page

    2010-01-01

    If life continues from generation to generation, then all plants and animals must go through a life cycle, even though it may be different from organism to organism. Is this what students have "learned," or do they have their own private conceptions about life cycles? The formative assessment probe "Does It Have a Life Cycle?" reveals some…

  4. CHOOSING DRIVING CYCLE OF HYBRID VEHICLE

    Directory of Open Access Journals (Sweden)

    A. Vorona

    2011-01-01

    Full Text Available The analysis of existing driving cycles was performed. After comparing some of the cycles, one specific driving cycle was selected for the hybrid vehicle as the most reliable in representing the real moving of the vehicle in operating conditions and which may be reproduced at experimental tests at the modeling roller stand.

  5. Teaching the Rock Cycle with Ease.

    Science.gov (United States)

    Bereki, Debra

    2000-01-01

    Describes a hands-on lesson for teaching high school students the concept of the rock cycle using sedimentary, metamorphic, and igneous rocks. Students use a rock cycle diagram to identify pairs of rocks. From the rock cycle, students explain on paper how their first rock became the second rock and vice versa. (PVD)

  6. 40 CFR 94.105 - Duty cycles.

    Science.gov (United States)

    2010-07-01

    ... EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Test Procedures § 94.105 Duty cycles. (a) Overview. For...) General cycle. Propulsion engines that are used with (or intended to be used with) fixed-pitch propellers, propeller-law auxiliary engines, and any other engines for which the other duty cycles of this section do...

  7. Life cycle assessment : Past, present, and future

    NARCIS (Netherlands)

    Guinée, Jeroen B.; Heijungs, Reinout; Huppes, Gjalt; Zamagni, Alessandra; Masoni, Paolo; Buonamici, Roberto; Ekvall, Tomas; Rydberg, Tomas

    2011-01-01

    Environmental life cycle assessment (LCA) has developed fast over the last three decades. Whereas LCA developed from merely energy analysis to a comprehensive environmental burden analysis in the 1970s, full-fledged life cycle impact assessment and life cycle costing models were introduced in the

  8. Round and Round the Water Cycle

    Science.gov (United States)

    Bradley, Barbara A.

    2017-01-01

    Children enjoy water play, and kindergarten children can learn about the water cycle. Teachers are already introducing elements of the water cycle when discussing weather and bodies of water. The water cycle also can be a springboard for teaching children about plants and animals and the importance of water for sustaining life and shaping our…

  9. Cycling efficiency and energy cost of walking in young and older adults.

    Science.gov (United States)

    Gaesser, Glenn A; Tucker, Wesley J; Sawyer, Brandon J; Bhammar, Dharini M; Angadi, Siddhartha S

    2018-02-01

    To determine whether age affects cycling efficiency and the energy cost of walking (Cw), 190 healthy adults, ages 18-81 yr, cycled on an ergometer at 50 W and walked on a treadmill at 1.34 m/s. Ventilation and gas exchange at rest and during exercise were used to calculate net Cw and net efficiency of cycling. Compared with the 18-40 yr age group (2.17 ± 0.33 J·kg -1 ·m -1 ), net Cw was not different in the 60-64 yr (2.20 ± 0.40 J·kg -1 ·m -1 ) and 65-69 yr (2.20 ± 0.28 J·kg -1 ·m -1 ) age groups, but was significantly ( P 60 yr, net Cw was significantly correlated with age ( R 2  = 0.123; P = 0.002). Cycling net efficiency was not different between 18-40 yr (23.5 ± 2.9%), 60-64 yr (24.5 ± 3.6%), 65-69 yr (23.3 ± 3.6%) and ≥70 yr (24.7 ± 2.7%) age groups. Repeat tests on a subset of subjects (walking, n = 43; cycling, n = 37) demonstrated high test-retest reliability [intraclass correlation coefficients (ICC), 0.74-0.86] for all energy outcome measures except cycling net energy expenditure (ICC = 0.54) and net efficiency (ICC = 0.50). Coefficients of variation for all variables ranged from 3.1 to 7.7%. Considerable individual variation in Cw and efficiency was evident, with a ~2-fold difference between the least and most economical/efficient subjects. We conclude that, between 18 and 81 yr, net Cw was only higher for ages ≥70 yr, and that cycling net efficiency was not different across age groups. NEW & NOTEWORTHY This study illustrates that the higher energy cost of walking in older adults is only evident for ages ≥70 yr. For older adults ages 60-69 yr, the energy cost of walking is similar to that of young adults. Cycling efficiency, by contrast, is not different across age groups. Considerable individual variation (∼2-fold) in cycling efficiency and energy cost of walking is observed in young and older adults.

  10. Activity cycles in members of young loose stellar associations

    Science.gov (United States)

    Distefano, E.; Lanzafame, A. C.; Lanza, A. F.; Messina, S.; Spada, F.

    2017-10-01

    Context. Magnetic cycles analogous to the solar cycle have been detected in tens of solar-like stars by analyzing long-term time series of different magnetic activity indexes. The relationship between the cycle properties and global stellar parameters is not fully understood yet. One reason for this is the lack of long-term time series for stars covering a wide range of stellar parameters. Aims: We searched for activity cycles in a sample of 90 young solar-like stars with ages between 4 and 95 Myr with the aim to investigate the properties of activity cycles in this age range. Methods: We measured the length Pcyc of a given cycle by analyzing the long-term time series of three different activity indexes: the period of rotational modulation, the amplitude of the rotational modulation and the median magnitude in the V band. For each star, we also computed the global magnetic activity index ⟨ IQR ⟩ that is proportional to the amplitude of the rotational modulation and can be regarded as a proxy of the mean level of the surface magnetic activity. Results: We detected activity cycles in 67 stars. Secondary cycles were also detected in 32 stars of the sample. The lack of correlation between Pcyc and Prot and the position of our targets in the Pcyc/Prot-Ro-1 diagram suggest that these stars belong to the so-called transitional branch and that the dynamo acting in these stars is different from the solar dynamo and from that acting in the older Mt. Wilson stars. This statement is also supported by the analysis of the butterfly diagrams whose patterns are very different from those seen in the solar case. We computed the Spearman correlation coefficient rS between Pcyc, ⟨ IQR ⟩ and various stellar parameters. We found that Pcyc in our sample is uncorrelated with all the investigated parameters. The ⟨ IQR ⟩ index is positively correlated with the convective turnover timescale, the magnetic diffusivity timescale τdiff, and the dynamo number DN, whereas it is anti

  11. The steel scrap age.

    Science.gov (United States)

    Pauliuk, Stefan; Milford, Rachel L; Müller, Daniel B; Allwood, Julian M

    2013-04-02

    Steel production accounts for 25% of industrial carbon emissions. Long-term forecasts of steel demand and scrap supply are needed to develop strategies for how the steel industry could respond to industrialization and urbanization in the developing world while simultaneously reducing its environmental impact, and in particular, its carbon footprint. We developed a dynamic stock model to estimate future final demand for steel and the available scrap for 10 world regions. Based on evidence from developed countries, we assumed that per capita in-use stocks will saturate eventually. We determined the response of the entire steel cycle to stock saturation, in particular the future split between primary and secondary steel production. During the 21st century, steel demand may peak in the developed world, China, the Middle East, Latin America, and India. As China completes its industrialization, global primary steel production may peak between 2020 and 2030 and decline thereafter. We developed a capacity model to show how extensive trade of finished steel could prolong the lifetime of the Chinese steelmaking assets. Secondary steel production will more than double by 2050, and it may surpass primary production between 2050 and 2060: the late 21st century can become the steel scrap age.

  12. Social Life Cycle Assessment Revisited

    Directory of Open Access Journals (Sweden)

    Ruqun Wu

    2014-07-01

    Full Text Available To promote the development of Social Life Cycle Assessment (SLCA, we conducted a comprehensive review of recently developed frameworks, methods, and characterization models for impact assessment for future method developers and SLCA practitioners. Two previous reviews served as our foundations for this review. We updated the review by including a comprehensive list of recently-developed SLCA frameworks, methods and characterization models. While a brief discussion from goal, data, and indicator perspectives is provided in Sections 2 to 4 for different frameworks/methods, the focus of this review is Section 5 where discussion on characterization models for impact assessment of different methods is provided. The characterization models are categorized into two types following the UNEP/SETAC guidelines: type I models without impact pathways and type II models with impact pathways. Different from methods incorporating type I/II characterization models, another LCA modeling approach, Life Cycle Attribute Assessment (LCAA, is also discussed in this review. We concluded that methods incorporating either type I or type II models have limitations. For type I models, the challenge lies in the systematic identification of relevant stakeholders and materiality issues; while for type II models, identification of impact pathways that most closely and accurately represent the real-world causal relationships is the key. LCAA may avoid these problems, but the ultimate questions differ from those asked by the methods using type I and II models.

  13. Technology development life cycle processes.

    Energy Technology Data Exchange (ETDEWEB)

    Beck, David Franklin

    2013-05-01

    This report and set of appendices are a collection of memoranda originally drafted in 2009 for the purpose of providing motivation and the necessary background material to support the definition and integration of engineering and management processes related to technology development. At the time there was interest and support to move from Capability Maturity Model Integration (CMMI) Level One (ad hoc processes) to Level Three. As presented herein, the material begins with a survey of open literature perspectives on technology development life cycles, including published data on %E2%80%9Cwhat went wrong.%E2%80%9D The main thrust of the material presents a rational expose%CC%81 of a structured technology development life cycle that uses the scientific method as a framework, with further rigor added from adapting relevant portions of the systems engineering process. The material concludes with a discussion on the use of multiple measures to assess technology maturity, including consideration of the viewpoint of potential users.

  14. MHD Integrated Topping Cycle Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990's, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

  15. Life Cycle Assessment of Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Sjunnesson, Jeannette

    2005-09-15

    This is an environmental study on concrete that follows the standard protocol of life cycle assessment (LCA). The study is done for two types of concrete, ordinary and frost-resistant concrete, and has an extra focus on the superplasticizers used as admixtures. The utilization phase is not included in this study since the type of construction for which the concrete is used is not defined and the concrete is assumed to be inert during this phase. The results show that it is the production of the raw material and the transports involved in the life cycle of concrete that are the main contributors to the total environmental load. The one single step in the raw material production that has the highest impact is the production of cement. Within the transportation operations the transportation of concrete is the largest contributor, followed by the transportation of the cement. The environmental impact of frost-resistant concrete is between 24-41 % higher than that of ordinary concrete due to its higher content of cement. Superplasticizers contribute with approximately 0.4-10.4 % of the total environmental impact of concrete, the least to the global warming potential (GWP) and the most to the photochemical ozone creation potential (POCP). Also the toxicity of the superplasticizers is investigated and the conclusion is that the low amount of leakage of superplasticizers from concrete leads to a low risk for the environment and for humans.

  16. Open-cycle OTEC system performance analysis. [Claude cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, A.A.; Olson, D.A.; Johnson, D.H.

    1980-10-01

    An algorithm developed to calculate the performance of Claude-Cycle ocean thermal energy conversion (OTEC) systems is described. The algorithm treats each component of the system separately and then interfaces them to form a complete system, allowing a component to be changed without changing the rest of the algorithm. Two components that are subject to change are the evaporator and condenser. For this study we developed mathematical models of a channel-flow evaporator and both a horizontal jet and spray director contact condenser. The algorithm was then programmed to run on SERI's CDC 7600 computer and used to calculate the effect on performance of deaerating the warm and cold water streams before entering the evaporator and condenser, respectively. This study indicates that there is no advantage to removing air from these streams compared with removing the air from the condenser.

  17. When Product Life Cycle Meets Customer Activity Cycle

    DEFF Research Database (Denmark)

    Tan, Adrian Ronald

    2007-01-01

    project in a global office furniture manufacturer, this paper attempts to uncover how a manufacturing company is making the move from selling office furniture to selling the benefit of workspace performance. A significant insight is that the definition of value is core to both relationship marketing......Manufacturing companies have traditionally focused their efforts on designing, developing and producing products to offer on the market. Today global competition and demands for greater company responsibility of products throughout their entire life cycle are driving manufacturing companies...... to shift market strategies from a transactional approach to an approach based on the establishment and management of customer relationships (Grönroos, 1999). A growing number of studies and research programmes have focused on the potentials of business strategies based on providing the value of utility...

  18. Advanced Fuel Cycle Economic Sensitivity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    David Shropshire; Kent Williams; J.D. Smith; Brent Boore

    2006-12-01

    A fuel cycle economic analysis was performed on four fuel cycles to provide a baseline for initial cost comparison using the Gen IV Economic Modeling Work Group G4 ECON spreadsheet model, Decision Programming Language software, the 2006 Advanced Fuel Cycle Cost Basis report, industry cost data, international papers, the nuclear power related cost study from MIT, Harvard, and the University of Chicago. The analysis developed and compared the fuel cycle cost component of the total cost of energy for a wide range of fuel cycles including: once through, thermal with fast recycle, continuous fast recycle, and thermal recycle.

  19. Revisiting super-cycles in commodity prices

    Directory of Open Access Journals (Sweden)

    Fatma Pınar Erdem

    2016-12-01

    Full Text Available It is argued that business cycles have been moderating. However, there are a limited number of studies in the literature analyzing the cyclical behaviour of commodity prices in the last decades. This paper attempts to fill this gap by investigating the super-cycles in oil prices. In addition, interdependence between cycles in GDP and oil prices and co-movements between cycles in oil and other commodity prices are investigated. Results show that super-cycles in oil prices still exist and are not moderating. The last peak in long-term oil price was observed in 2012 and since then it has been on a downward trend.

  20. On acyclicity of games with cycles

    DEFF Research Database (Denmark)

    Andersson, Klas Olof Daniel; Hansen, Thomas Dueholm; Gurvich, Vladimir

    2010-01-01

    We study restricted improvement cycles (ri-cycles) in finite positional n-person games with perfect information modeled by directed graphs (di-graphs) that may contain directed cycles (di-cycles). We assume that all these di-cycles form one outcome c, for example, a draw. We obtain criteria...... of restricted improvement acyclicity (ri-acyclicity) in two cases: for n D 2 and for acyclic di-graphs. We provide several examples that outline the limits of these criteria and show that, essentially, there are no other ri-acyclic cases. We also discuss connections between ri-acyclicity and some open problems...

  1. Intermittent Stem Cell Cycling Balances Self-Renewal and Senescence of the C. elegans Germ Line.

    Directory of Open Access Journals (Sweden)

    Amanda Cinquin

    2016-04-01

    Full Text Available Self-renewing organs often experience a decline in function in the course of aging. It is unclear whether chronological age or external factors control this decline, or whether it is driven by stem cell self-renewal-for example, because cycling cells exhaust their replicative capacity and become senescent. Here we assay the relationship between stem cell cycling and senescence in the Caenorhabditis elegans reproductive system, defining this senescence as the progressive decline in "reproductive capacity," i.e. in the number of progeny that can be produced until cessation of reproduction. We show that stem cell cycling diminishes remaining reproductive capacity, at least in part through the DNA damage response. Paradoxically, gonads kept under conditions that preclude reproduction keep cycling and producing cells that undergo apoptosis or are laid as unfertilized gametes, thus squandering reproductive capacity. We show that continued activity is in fact beneficial inasmuch as gonads that are active when reproduction is initiated have more sustained early progeny production. Intriguingly, continued cycling is intermittent-gonads switch between active and dormant states-and in all likelihood stochastic. Other organs face tradeoffs whereby stem cell cycling has the beneficial effect of providing freshly-differentiated cells and the detrimental effect of increasing the likelihood of cancer or senescence; stochastic stem cell cycling may allow for a subset of cells to preserve proliferative potential in old age, which may implement a strategy to deal with uncertainty as to the total amount of proliferation to be undergone over an organism's lifespan.

  2. TryCYCLE: A Prospective Study of the Safety and Feasibility of Early In-Bed Cycling in Mechanically Ventilated Patients.

    Science.gov (United States)

    Kho, Michelle E; Molloy, Alexander J; Clarke, France J; Ajami, Daana; McCaughan, Magda; Obrovac, Kristy; Murphy, Christina; Camposilvan, Laura; Herridge, Margaret S; Koo, Karen K Y; Rudkowski, Jill; Seely, Andrew J E; Zanni, Jennifer M; Mourtzakis, Marina; Piraino, Thomas; Cook, Deborah J

    2016-01-01

    The objective of this study was to assess the safety and feasibility of in-bed cycling started within the first 4 days of mechanical ventilation (MV) to inform a future randomized clinical trial. We conducted a 33-patient prospective cohort study in a 21-bed adult academic medical-surgical intensive care unit (ICU) in Hamilton, ON, Canada. We included adult patients (≥ 18 years) receiving MV who walked independently pre-ICU. Our intervention was 30 minutes of in-bed supine cycling 6 days/week in the ICU. Our primary outcome was Safety (termination), measured as events prompting cycling termination; secondary Safety (disconnection or dislodgement) outcomes included catheter/tube dislodgements. Feasibility was measured as consent rate and fidelity to intervention. For our primary outcome, we calculated the binary proportion and 95% confidence interval (CI). From 10/2013-8/2014, we obtained consent from 34 of 37 patients approached (91.9%), 33 of whom received in-bed cycling. Of those who cycled, 16(48.4%) were female, the mean (SD) age was 65.8(12.2) years, and APACHE II score was 24.3(6.7); 29(87.9%) had medical admitting diagnoses. Cycling termination was infrequent (2.0%, 95% CI: 0.8%-4.9%) and no device dislodgements occurred. Cycling began a median [IQR] of 3 [2, 4] days after ICU admission; patients received 5 [3, 8] cycling sessions with a median duration of 30.7 [21.6, 30.8] minutes per session. During 205 total cycling sessions, patients were receiving invasive MV (150 [73.1%]), vasopressors (6 [2.9%]), sedative or analgesic infusions (77 [37.6%]) and dialysis (4 [2.0%]). Early cycling within the first 4 days of MV among hemodynamically stable patients is safe and feasible. Research to evaluate the effect of early cycling on patient function is warranted. Clinicaltrials.gov: NCT01885442.

  3. Menstrual cycle and its disorders in women with congenital heart disease.

    NARCIS (Netherlands)

    Drenthen, W.; Hoendermis, E.S.; Moons, P.; Heida, K.Y.; Roos-Hesselink, J.W.; Mulder, B.J.M.; Dijk, A.P.J. van; Vliegen, H.W.; Sollie, K.M.; Berger, R.M.; Lely, A.T.; Canobbio, M.M.; Pieper, P.G.

    2008-01-01

    OBJECTIVES: To investigate the age at menarche, the prevalence of menstrual cycle (interval) disorders, and determinants in women with congenital heart disease (CHD). DESIGN: Using two CHD registries, 1802 (82%) of the 2196 women with CHD contacted (aged 18-58 years) provided written informed

  4. Menstrual cycle and its disorders in women with congenital heart disease

    NARCIS (Netherlands)

    Drenthen, Willem; Hoendermis, Elke S.; Moons, Philip; Heida, Karst Y.; Roos-Hesselink, Jolien W.; Mulder, Barbara J.M.; Van Dijk, Arie P.J.; Vliegen, Hubert W.; Sollie, Krystyna M.; Berger, Rolf M.F.; Lely, A. Titia; Canobbio, Mary M.; Pieper, Petronella G.; Berger, Rudolphus

    2008-01-01

    OBJECTIVES: To investigate the age at menarche, the prevalence of menstrual cycle (interval) disorders, and determinants in women with congenital heart disease (CHD). DESIGN: Using two CHD registries, 1802 (82%) of the 2196 women with CHD contacted (aged 18-58 years) provided written informed

  5. Circulating microRNA Profile throughout the menstrual cycle.

    Directory of Open Access Journals (Sweden)

    Kadri Rekker

    Full Text Available Normal physiological variables, such as age and gender, contribute to alterations in circulating microRNA (miRNA expression levels. The changes in the female body during the menstrual cycle can also be reflected in plasma miRNA expression levels. Therefore, this study aimed to determine the plasma miRNA profile of healthy women during the menstrual cycle and to assess which circulating miRNAs are derived from blood cells. The plasma miRNA expression profiles in nine healthy women were determined by quantitative real time PCR using Exiqon Human Panel I assays from four time-points of the menstrual cycle. This platform was also used for studying miRNAs from pooled whole blood RNA samples at the same four time-points. Our results indicated that circulating miRNA expression levels in healthy women were not significantly altered by the processes occurring during the menstrual cycle. No significant differences in plasma miRNA expression levels were observed between the menstrual cycle time-points, but the number of detected miRNAs showed considerable variation among the studied individuals. miRNA analysis from whole blood samples revealed that majority of miRNAs in plasma are derived from blood cells. The most abundant miRNA in plasma and blood was hsa-miR-451a, but a number of miRNAs were only detected in one or the other sample type. In conclusion, our data suggest that the changes in the female body during the menstrual cycle do not affect the expression of circulating miRNAs at measurable levels.

  6. VISION: Verifiable Fuel Cycle Simulation Model

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

    2009-04-01

    The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

  7. Fuel Cycle System Analysis Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Steven J. Piet; Brent W. Dixon; Dirk Gombert; Edward A. Hoffman; Gretchen E. Matthern; Kent A. Williams

    2009-06-01

    This Handbook aims to improve understanding and communication regarding nuclear fuel cycle options. It is intended to assist DOE, Campaign Managers, and other presenters prepare presentations and reports. When looking for information, check here. The Handbook generally includes few details of how calculations were performed, which can be found by consulting references provided to the reader. The Handbook emphasizes results in the form of graphics and diagrams, with only enough text to explain the graphic, to ensure that the messages associated with the graphic is clear, and to explain key assumptions and methods that cause the graphed results. Some of the material is new and is not found in previous reports, for example: (1) Section 3 has system-level mass flow diagrams for 0-tier (once-through), 1-tier (UOX to CR=0.50 fast reactor), and 2-tier (UOX to MOX-Pu to CR=0.50 fast reactor) scenarios - at both static and dynamic equilibrium. (2) To help inform fast reactor transuranic (TRU) conversion ratio and uranium supply behavior, section 5 provides the sustainable fast reactor growth rate as a function of TRU conversion ratio. (3) To help clarify the difference in recycling Pu, NpPu, NpPuAm, and all-TRU, section 5 provides mass fraction, gamma, and neutron emission for those four cases for MOX, heterogeneous LWR IMF (assemblies mixing IMF and UOX pins), and a CR=0.50 fast reactor. There are data for the first 10 LWR recycle passes and equilibrium. (4) Section 6 provides information on the cycle length, planned and unplanned outages, and TRU enrichment as a function of fast reactor TRU conversion ratio, as well as the dilution of TRU feedstock by uranium in making fast reactor fuel. (The recovered uranium is considered to be more pure than recovered TRU.) The latter parameter impacts the required TRU impurity limits specified by the Fuels Campaign. (5) Section 7 provides flows for an 800-tonne UOX separation plant. (6) To complement 'tornado' economic

  8. Live-Birth Rate Associated With Repeat In Vitro Fertilization Treatment Cycles.

    Science.gov (United States)

    Smith, Andrew D A C; Tilling, Kate; Nelson, Scott M; Lawlor, Debbie A

    The likelihood of achieving a live birth with repeat in vitro fertilization (IVF) is unclear, yet treatment is commonly limited to 3 or 4 embryo transfers. To determine the live-birth rate per initiated ovarian stimulation IVF cycle and with repeated cycles. Prospective study of 156,947 UK women who received 257,398 IVF ovarian stimulation cycles between 2003 and 2010 and were followed up until June 2012. In vitro fertilization, with a cycle defined as an episode of ovarian stimulation and all subsequent separate fresh and frozen embryo transfers. Live-birth rate per IVF cycle and the cumulative live-birth rates across all cycles in all women and by age and treatment type. Optimal, prognosis-adjusted, and conservative cumulative live-birth rates were estimated, reflecting 0%, 30%, and 100%, respectively, of women who discontinued due to poor prognosis and having a live-birth rate of 0 had they continued. Among the 156,947 women, the median age at start of treatment was 35 years (interquartile range, 32-38; range, 18-55), and the median duration of infertility for all 257,398 cycles was 4 years (interquartile range, 2-6; range, live-birth rate for the first cycle was 29.5% (95% CI, 29.3%-29.7%). This remained above 20% up to and including the fourth cycle. The cumulative prognosis-adjusted live-birth rate across all cycles continued to increase up to the ninth cycle, with 65.3% (95% CI, 64.8%-65.8%) of women achieving a live birth by the sixth cycle. In women younger than 40 years using their own oocytes, the live-birth rate for the first cycle was 32.3% (95% CI, 32.0%-32.5%) and remained above 20% up to and including the fourth cycle. Six cycles achieved a cumulative prognosis-adjusted live-birth rate of 68.4% (95% CI, 67.8%-68.9%). For women aged 40 to 42 years, the live-birth rate for the first cycle was 12.3% (95% CI, 11.8%-12.8%), with 6 cycles achieving a cumulative prognosis-adjusted live-birth rate of 31.5% (95% CI, 29.7%-33.3%). For women older than 42

  9. Thorium nuclear fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Tae Yoon; Do, Jae Bum; Choi, Yoon Dong; Park, Kyoung Kyum; Choi, In Kyu; Lee, Jae Won; Song, Woong Sup; Kim, Heong Woo

    1998-03-01

    Since thorium produces relatively small amount of TRU elements after irradiation in the reactor, it is considered one of possible media to mix with the elements to be transmuted. Both solid and molten-salt thorium fuel cycles were investigated. Transmutation concepts being studied involved fast breeder reactor, accelerator-driven subcritical reactor, and energy amplifier with thorium. Long-lived radionuclides, especially TRU elements, could be separated from spent fuel by a pyrochemical process which is evaluated to be proliferation resistance. Pyrochemical processes of IFR, MSRE and ATW were reviewed and evaluated in detail, regarding technological feasibility, compatibility of thorium with TRU, proliferation resistance, their economy and safety. (author). 26 refs., 22 figs

  10. Wireless Crankarm Dynamometer for Cycling

    Directory of Open Access Journals (Sweden)

    Caetano Decian LAZZARI

    2011-05-01

    Full Text Available This report describes a new crankarm dynamometer designed to evaluate the strength produced by cyclists in real conditions. The dynamometer was designed to be fitted on a conventional crankset while data were transmitted via wireless communication channels available on a BluetoothTM module. Some 3D solid models were created in the SolidsWorks2010TM development environment to analyze the static and dynamic characteristics, by using the finite elements technique. Each crankset arm was used as a load cell based on strain gages configured as two Wheatstone bridges. The signals were conditioned on a printed circuit board attached directly to the structure. As a result, the load cell shows a maximum nonlinearity error between 2.1 % and 2.8 %. Some tests were performed on a cycling trainer, allowing to evaluate the system's functionality and to determine the involved forces in the crankset.

  11. Annual Cycle Energy System (ACES)

    Science.gov (United States)

    Holman, A. S.; Abbatiello, L. A.

    1980-05-01

    A single family residence near Knoxville, Tennessee, is being used to demonstrate the energy conserving features of the annual cycle energy system (ACES), an integrated heating and cooling system that utilizes a unidirectional heat pump and low temperature thermal storage. A second house, the control house, is being used to compare the performance of the ACES with that of an electric resistance heating and hot water system combined with a central air conditioning system. The ACES reduced peak utility system demands significantly: a reduction from 11.7 to 3.1 kW was achieved in the winter and from 4.1 to 0.7 kW in the summer. The only problems encountered were a heat leak into the storage bin that was twice the calculated value and control logic errors that produced excessive hot water in the winter, requiring extensive use of the night heat rejection mode in the summer. These problems are currently being corrected.

  12. Ferroelectric Stirling-Cycle Refrigerator

    Science.gov (United States)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    A Stirling-cycle refrigerator has a three-pump configuration and pumping sequence, in which one pump serves as a compressor. one pump serves as an expander, and one pump serves as a displacer. The pumps are ferroelectrically actuated diaphragm pumps which are coordinated by synchronizing the ferroelectric-actuator voltages in such a way that the net effect of the displacer is to reduce the deleterious effect of dead space; that is, to circulate a greater fraction of the working fluid through the heat exchangers than would be possible by use of the compressor and expander alone. In addition. the displacer can be controlled separately to make the flow of working fluid in the heat exchangers turbulent (to increase the rate of transfer of heat at the cost of greater resistance to flow) or laminar (to decrease the resistance to flow at the cost of a lower heat-transfer rate).

  13. Digital daily cycles of individuals

    DEFF Research Database (Denmark)

    Aledavood, Talayeh; Jørgensen, Sune Lehmann; Saramäki, Jari

    2015-01-01

    day-night pattern, there are individual differences: e.g., some of us are intrinsically morning-active, while others prefer evenings. In this article, we look at digital daily cycles: circadian patterns of activity viewed through the lens of auto-recorded data of communication and online activity. We...... begin at the aggregate level, discuss earlier results, and illustrate differences between population-level daily rhythms in different media. Then we move on to the individual level, and show that there is a strong individual-level variation beyond averages: individuals typically have their distinctive...... daily pattern that persists in time. We conclude by discussing the driving forces behind these signature daily patterns, from personal traits (morningness/eveningness) to variation in activity level and external constraints, and outline possibilities for future research....

  14. Violence as a Vicious Cycle

    Directory of Open Access Journals (Sweden)

    Huseyin Gulec

    2012-03-01

    Full Text Available Since the conclusion that the violence as a behavior is not (cannot be determined within an absolute genetic determinism has been reached for long years, environmental factors are increasingly examined. We witness that human behavior in society can easily convert into coping with stressful events with violence. Individual or social violence as a behavior has a similar pattern with violence committed in primitive society and by children. After a brief review of violence, its description, etiological theories and types, this article majorly focuses on children and their early and late response to violence. The purpose here is to draw attention to the individuals who were previously exposed to violence (either directly or indirectly resort to violence, perpetuating a vicious cycle.

  15. Medical coverage of cycling events.

    Science.gov (United States)

    Martinez, John M

    2006-05-01

    Medical coverage of recreational and competitive cycling events requires significant planning and cooperation among the race and medical directors, race officials, and local emergency medical services. The medical team should be proficient in treating minor and self-limiting injuries such as abrasions and minor trauma. The medical team should also have contingency plans for medical emergencies, such as cardiac events and major trauma, that ensure rapid stabilization and transport of the athlete to the appropriate medical facility. Stationary and mobile medical teams may be necessary for proper coverage of the event. Event day communication systems between individual medical staff as well as race officials and local emergency medical services is important to the success of the event.

  16. Global biogeochemical cycle of vanadium.

    Science.gov (United States)

    Schlesinger, William H; Klein, Emily M; Vengosh, Avner

    2017-12-26

    Synthesizing published data, we provide a quantitative summary of the global biogeochemical cycle of vanadium (V), including both human-derived and natural fluxes. Through mining of V ores (130 × 109 g V/y) and extraction and combustion of fossil fuels (600 × 109 g V/y), humans are the predominant force in the geochemical cycle of V at Earth's surface. Human emissions of V to the atmosphere are now likely to exceed background emissions by as much as a factor of 1.7, and, presumably, we have altered the deposition of V from the atmosphere by a similar amount. Excessive V in air and water has potential, but poorly documented, consequences for human health. Much of the atmospheric flux probably derives from emissions from the combustion of fossil fuels, but the magnitude of this flux depends on the type of fuel, with relatively low emissions from coal and higher contributions from heavy crude oils, tar sands bitumen, and petroleum coke. Increasing interest in petroleum derived from unconventional deposits is likely to lead to greater emissions of V to the atmosphere in the near future. Our analysis further suggests that the flux of V in rivers has been incremented by about 15% from human activities. Overall, the budget of dissolved V in the oceans is remarkably well balanced-with about 40 × 109 g V/y to 50 × 109 g V/y inputs and outputs, and a mean residence time for dissolved V in seawater of about 130,000 y with respect to inputs from rivers.

  17. MHD limit cycles on FTU

    Science.gov (United States)

    Pucella, G.; Giovannozzi, E.; Buratti, P.; Cianfarani, C.

    2017-11-01

    The development of low-order tearing modes during density ramp-up in the high density regime on the Frascati Tokamak Upgrade is characterized by an initial ordinary stage, with a ‘one-to-one’ relation between mode amplitude and frequency, followed by the formation, on the amplitude/frequency plane, of ‘limit cycles’ with increasing area up to disruption for density limit if the density continues to grow. A critical mode amplitude for transition from smooth to cyclic behavior has been observed in experiments performed changing the line-averaged density, and the existence of such a threshold has been confirmed in experiments of real time control of tearing mode in the high density regime by means of electron cyclotron resonance heating. The amplitude and frequency modulations of the observed m/n=2/1 tearing mode (m and n are the poloidal and toroidal mode number, respectively) occur in few milliseconds, which is not in agreement with the diffusion resistive time of about two hundred milliseconds expected on the q=2 resonance from the non-linear theory. The origin of such modulations has been investigated, taking into account that in the high amplitude stages of the mode temporal evolution it is difficult to discriminate between non-linear effects and mode coupling mechanisms. Our analysis suggests that the formation of limit cycles could be due to a recursive island fragmentation, with a sort of self-healing phenomenon; in fact the island distortion increases before amplitude drops. Concerning the interaction with modes of different helicity, our experiments seem to indicate that the presence of the q=3 resonance in the plasma is necessary for the occurrence of deep and regular limit cycles for the 2/1 tearing mode.

  18. Numerical analysis and field study of time dependent exergy-energy of a gas-steam combined cycle

    Directory of Open Access Journals (Sweden)

    Barari Bamdad

    2012-01-01

    Full Text Available In this study, time dependent exergy analysis of the Fars Combined Power Plant Cycle has been investigated. Exergy analysis has been used for investigating each part of actual combined cycle by considering irreversibility from Apr 2006 to Oct 2010. Performance analysis has been done for each part by evaluating exergy destruction in each month. By using of exergy analysis, aging of each part has been evaluated respect to time duration. In addition, the rate of lost work for each month has been calculated and variation of this parameter has been considered as a function of aging rate. Finally, effects of exergy destruction of each part have been investigated on exergy destruction of whole cycle. Entire analysis has been done for Unit 3 and 4 of gas turbine cycle which combined by Unit B of steam cycle in Fars Combined Power Plant Cycle located in Fars province in Iran.

  19. Subclinical hypothyroidism: Is it important in intracytoplasmic sperm injection cycles?

    Science.gov (United States)

    Çalışkan, Eray; Ergin, Rahime Nida; Öztekin, Deniz Can; Kars, Bülent; Çakır, Seda; Sofuoğlu, Kenan

    2017-06-01

    To compare intracytoplasmic sperm injection (ICSI) outcomes of women with subclinical hypothyroidism with those of euthyroid women. A retrospective case-control study was conducted. Out of 2529 ICSI cycles evaluated, 41 women with hypothyroidism, 28 women with hyperthyroidism, and 128 women with subclinical hyperthyroidism were excluded, and 2336 cycles were analyzed. Women were identified as having subclinical hypothyroidism (case group, n=105) in the presence of a thyroid-stimulating hormone level >4.5 mU/L and normal free T4 and compared with euthyroid controls (n=2231). The mean age, body mass index, day 3 follicle-stimulating hormone level, and antral follicle count of the study patients were similar to the control group (p>0.5). The cycle cancellation rate of the study group was similar to the control group (13.3% vs. 7.6%, p=0.1). The clinical pregnancy rate was 21.2% in the study group, which was significantly lower than the 35.8% in the control group (p=0.04). The take-home baby rate was also significantly lower in the study group compared with the control groups (13.5% vs. 31.4% respectively, p=0.01). Both the clinical pregnancy rate and the take-home baby rate is lower in women with subclinical hypothyroidism at the time of ICSI cycle.

  20. Characterization of chaotic dynamics in the human menstrual cycle

    Science.gov (United States)

    Derry, Gregory; Derry, Paula

    2010-03-01

    The human menstrual cycle exhibits much unexplained variability, which is typically dismissed as random variation. Given the many delayed nonlinear feedbacks in the reproductive endocrine system, however, the menstrual cycle might well be a nonlinear dynamical system in a chaotic trajectory, and that this instead accounts for the observed variability. Here, we test this hypothesis by performing a time series analysis on data for 7438 menstrual cycles from 38 women in the 20-40 year age range, using the database maintained by the Tremin Research Program on Women's Health. Using phase space reconstruction techniques with a maximum embedding dimension of 6, we find appropriate scaling behavior in the correlation sums for this data, indicating low dimensional deterministic dynamics. A correlation dimension of 2.6 is measured in this scaling regime, and this result is confirmed by recalculation using the Takens estimator. These results may be interpreted as offering an approximation to the fractal dimension of a strange attractor governing the chaotic dynamics of the menstrual cycle.