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Sample records for age-predicted maximal heart

  1. Revisiting age-predicted maximal heart rate: Can it be used as a valid measure of effort?

    PubMed Central

    Arena, Ross; Myers, Jonathan; Kaminsky, Leonard A.

    2016-01-01

    Introduction Despite high error ranges, age-predicted maximal heart rate (APMHR) is frequently used to gauge the achievement of adequate effort during an exercise test. The current analysis revisits this issue using the Fitness Registry and the Importance of Exercise: National Database (FRIEND Registry). Methods A total of 4,796 (63% male) apparently healthy subjects underwent a maximal cardiopulmonary exercise test on a treadmill. The mean age, maximal heart rate (HR), and maximal aerobic capacity of the cohort were 43 ± 12 years, 178 ± 15 beats per minute, and 36.1 ± 10.6 mlO2 · kg−1 · min−1, respectively. All subjects reached or surpassed a peak respiratory exchange ratio of 1.10. A linear regression equation using age to predict maximal HR was validated in 3,796 subjects and cross-validated in the remaining 1,000 (randomly assigned). Results The APMHR equation in the validation cohort was as follows: 209.3 – 0.72(age). The r value and standard error of estimate for this regression was 0.61 (P < .001) and 11.35 beats/min, respectively. A 1-sample t test revealed that the mean difference between actual maximal HR and APMHR was not significantly different from 0 (mean difference = 0.32, P = .43). However, Bland-Altman revealed high limits of agreement (upper 25.31 and lower −24.67) and a significant proportional bias. Discussion The APMHR equation derived from this analysis included a large cohort of apparently healthy individuals with maximal exercise effort validated by the criterion standard (ie, peak respiratory exchange ratio). Using APMHR in this capacity should be discouraged, and new approaches to gauging an individual's exercise effort should be explored. PMID:26920596

  2. Resting and maximal heart rates in ectothermic vertebrates.

    PubMed

    Lillywhite, H B; Zippel, K C; Farrell, A P

    1999-12-01

    Resting and maximal heart rates (HR) in ectothermic vertebrates are generally lower than those in endotherms and vary by more than an order of magnitude interspecifically. Variation of HR transcends phylogeny and is influenced by numerous factors including temperature, activity, gas exchange, intracardiac shunts, pH, posture, and reflexogenic regulation of blood pressure. The characteristic resting HR is rarely the intrinsic rate of the pacemaker, which is primarily modulated by cholinergic inhibition and adrenergic excitation in most species. Neuropeptides also appear to be involved in cardiac regulation, although their role is not well understood. The principal determinants of resting HR include temperature, metabolic rate and hemodynamic requirements. Maximal HRs generally do not exceed 120 b min-1, but notable exceptions include the heterothermic tuna and small reptiles having HRs in excess of 300 b min-1 at higher body temperatures. Temperature affects the intrinsic pacemaker rate as well as the relative influence of adrenergic and cholinergic modulation. It also influences the evolved capability to increase HR, with maximal cardiac responses matched to preferred body temperatures in some species. Additional factors either facilitate or limit the maximal level of HR, including: (1) characteristics of the pacemaker potential; (2) development of sarcoplasmic reticulum as a calcium store in excitation-contraction coupling; (3) low-resistance coupling of myocardial cells; (4) limitations of force development imposed by rate changes; (5) efficacy of sympathetic modulation; and (6) development of coronary circulation to enhance oxygen delivery to myocardium. In evolutionary terms, both hemodynamic and oxygen requirements appear to have been key selection pressures for rapid cardiac rates.

  3. The effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake.

    PubMed

    Oh, Deuk-Ja; Hong, Hyeon-Ok; Lee, Bo-Ae

    2016-02-01

    The purpose of this study is to investigate the effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake. To achieve the purpose of the study, a total of 30 subjects were selected, including 15 people who performed continued regular exercises and 15 people as the control group. With regard to data processing, the IBM SPSS Statistics ver. 21.0 was used to calculate the mean and standard deviation. The difference of mean change between groups was verified through an independent t-test. As a result, there were significant differences in resting heart rate, maximal heart rate, maximal systolic blood pressure, and maximal oxygen uptake. However, the maximal systolic blood pressure was found to be an exercise-induced high blood pressure. Thus, it is thought that a risk diagnosis for it through a regular exercise stress test is necessary.

  4. Maximizing the Effectiveness of Ablation for Arrhythmias in the Congenital Heart Patients.

    PubMed

    Arujuna, Aruna; de Bono, Joseph

    2016-07-01

    Arrhythmias are common in adults with congenital heart disease and account for a large proportion of hospitalizations. The complex anatomical heterogeneity, often in the presence of a delicate hemodynamic system, presents a significant electrophysiological challenge. This review outlines current clinical practice and advances in maximizing the effectiveness of ablation for arrhythmias in congenital heart patients.

  5. Evaluating the Prediction of Maximal Heart Rate in Children and Adolescents

    ERIC Educational Resources Information Center

    Mahon, Anthony D.; Marjerrison, Andrea D.; Lee, Jonah D.; Woodruff, Megan E.; Hanna, Lauren E.

    2010-01-01

    In this study, we compared measured maximal heart rate (HRmax) to two different HRmax prediction equations [220-age and 208-0.7(age)] in 52 children ages 7-17 years. We determined the relationship of chronological age, maturational age, and resting HR to measured HRmax and assessed seated resting HR and HRmax during a graded exercise test.…

  6. Prediction of heart rate and oxygen uptake during incremental and maximal exercise in healthy adults.

    PubMed

    Fairbarn, M S; Blackie, S P; McElvaney, N G; Wiggs, B R; Paré, P D; Pardy, R L

    1994-05-01

    Measurement of heart rate and oxygen uptake during incremental exercise and at maximal exercise is useful in evaluating mechanisms responsible for exercise limitation in patients with cardiopulmonary disease. Presently used prediction equations are based on relatively small groups of subjects in whom there was an uneven distribution of subjects with regard to age and sex or based on equations that were from extrapolated data. Our prediction equations are based on data from 231 men and women equally divided within decades between 20 and 80 years. Patients exercised to a symptom-limited maximum on a cycle ergometer while measurements of heart rate and oxygen uptake were recorded. The relationship between heart rate and oxygen uptake throughout exercise (HR:VO2) was determined using a statistical technique that included each data point from each subject. The HR:VO2 throughout incremental exercise was best described by separate equations for women younger than 50 years and older than 50 years and for men younger than 70 years and older than 70 years. Prediction equations for maximal heart rate (HRmax) and maximal oxygen uptake (VO2max) were developed by linear regression and were selected from all possible combinations of parameters. The HRmax was most accurately predicted by age alone for both sexes. Unlike the HR:VO2 relationship, the slope of the line relating heart rate to age was not different for the older women compared with the younger women so that a single equation was derived to predict HRmax. A single equation for the men was also sufficient since the slope of heart rate to age was the same for all ages. To most accurately predict VO2max, a separate equation was required for both the women and men that included age, height, and weight.

  7. Adrenergic Receptor Polymorphism and Maximal Exercise Capacity after Orthotopic Heart Transplantation

    PubMed Central

    Feliciano, Helene; Martin, David; Regamey, Julien; Tozzi, Piergiorgio; Meyer, Philippe; Hullin, Roger

    2016-01-01

    Background Maximal exercise capacity after heart transplantion (HTx) is reduced to the 50–70% level of healthy controls when assessed by cardiopulmonary exercise testing (CPET) despite of normal left ventricular function of the donor heart. This study investigates the role of donor heart β1 and β2- adrenergic receptor (AR) polymorphisms for maximal exercise capacity after orthotopic HTx. Methods CPET measured peak VO2 as outcome parameter for maximal exercise in HTx recipients ≥9 months and ≤4 years post-transplant (n = 41; mean peak VO2: 57±15% of predicted value). Donor hearts were genotyped for polymorphisms of the β1-AR (Ser49Gly, Arg389Gly) and the β2-AR (Arg16Gly, Gln27Glu). Circumferential shortening of the left ventricle was measured using magnetic resonance based CSPAMM tagging. Results Peak VO2 was higher in donor hearts expressing the β1-Ser49Ser alleles when compared with β1-Gly49 carriers (60±15% vs. 47±10% of the predicted value; p = 0.015), and by trend in cardiac allografts with the β1-AR Gly389Gly vs. β1-Arg389 (61±15% vs. 54±14%, p = 0.093). Peak VO2 was highest for the haplotype Ser49Ser-Gly389, and decreased progressively for Ser49Ser-Arg389Arg > 49Gly-389Gly > 49Gly-Arg389Arg (adjusted R2 = 0.56, p = 0.003). Peak VO2 was not different for the tested β2-AR polymorphisms. Independent predictors of peak VO2 (adjusted R2 = 0.55) were β1-AR Ser49Gly SNP (p = 0.005), heart rate increase (p = 0.016), and peak systolic blood pressure (p = 0.031). Left ventricular (LV) motion kinetics as measured by cardiac MRI CSPAMM tagging at rest was not different between carriers and non-carriers of the β1-AR Gly49allele. Conclusion Similar LV cardiac motion kinetics at rest in donor hearts carrying either β1-AR Gly49 or β1-Ser49Ser variant suggests exercise-induced desensitization and down-regulation of the β1-AR Gly49 variant as relevant pathomechanism for reduced peak VO2 in β1-AR Gly49 carriers. PMID:27669015

  8. Heart rate recovery after maximal exercise is blunted in hypertensive seniors.

    PubMed

    Best, Stuart A; Bivens, Tiffany B; Dean Palmer, M; Boyd, Kara N; Melyn Galbreath, M; Okada, Yoshiyuki; Carrick-Ranson, Graeme; Fujimoto, Naoki; Shibata, Shigeki; Hastings, Jeffrey L; Spencer, Matthew D; Tarumi, Takashi; Levine, Benjamin D; Fu, Qi

    2014-12-01

    Abnormal heart rate recovery (HRR) after maximal exercise may indicate autonomic dysfunction and is a predictor for cardiovascular mortality. HRR is attenuated with aging and in middle-age hypertensive patients, but it is unknown whether HRR is attenuated in older-age adults with hypertension. This study compared HRR among 16 unmedicated stage 1 hypertensive (HTN) participants [nine men/seven women; 68 ± 5 (SD) yr; awake ambulatory blood pressure (BP) 149 ± 10/87 ± 7 mmHg] and 16 normotensive [control (CON)] participants (nine men/seven women; 67 ± 5 yr; 122 ± 4/72 ± 5 mmHg). HR, BP, oxygen uptake (V̇o2), cardiac output (Qc), and stroke volume (SV) were measured at rest, at two steady-state work rates, and graded exercise to peak during maximal treadmill exercise. During 6 min of seated recovery, the change in HR (ΔHR) was obtained every minute and BP every 2 min. In addition, HRR and R-R interval (RRI) recovery kinetics were analyzed using a monoexponential function, and the indexes (HRRI and RRII) were calculated. Maximum V̇o2, HR, Qc, and SV responses during exercise were not different between groups. ΔHR was significantly different (P < 0.001) between the HTN group (26 ± 8) and the CON group (36 ± 12 beats/min) after 1 min of recovery but less convincing at 2 min (P = 0.055). BP recovery was similar between groups. HRRI was significantly lower (P = 0.016), and there was a trend of lower RRII (P = 0.066) in the HTN group compared with the CON group. These results show that in older-age adults, HRR is attenuated further with the presence of hypertension, which may be attributable to an impairment of autonomic function.

  9. Baroreflex-mediated heart rate and vascular resistance responses 24 h after maximal exercise

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.

    2003-01-01

    INTRODUCTION: Plasma volume, heart rate (HR) variability, and stimulus-response relationships for baroreflex control of forearm vascular resistance (FVR) and HR were studied in eight healthy men after and without performing a bout of maximal exercise to test the hypotheses that acute expansion of plasma volume is associated with 1) reduction in baroreflex-mediated HR response, and 2) altered operational range for central venous pressure (CVP). METHODS: The relationship between stimulus (DeltaCVP) and vasoconstrictive reflex response (DeltaFVR) during unloading of cardiopulmonary baroreceptors was assessed with lower-body negative pressure (LBNP, 0, -5, -10, -15, -20 mm Hg). The relationship between stimulus (Deltamean arterial pressure (MAP)) and cardiac reflex response (DeltaHR) during loading of arterial baroreceptors was assessed with steady-state infusion of phenylephrine (PE) designed to increase MAP by 15 mm Hg alone and during application of LBNP (PE+LBNP) and neck pressure (PE+LBNP+NP). Measurements of vascular volume and autonomic baroreflex responses were conducted on two different test days, each separated by at least 1 wk. On one day, baroreflex response was tested 24 h after graded cycle exercise to volitional exhaustion. On another day, measurement of baroreflex response was repeated with no exercise (control). The order of exercise and control treatments was counterbalanced. RESULTS: Baseline CVP was elevated (P = 0.04) from a control value of 10.5 +/- 0.4 to 12.3 +/- 0.4 mm Hg 24 h after exercise. Average DeltaFVR/DeltaCVP during LBNP was not different (P = 0.942) between the exercise (-1.35 +/- 0.32 pru x mm Hg-1) and control (-1.32 +/- 0.36 pru x mm Hg-1) conditions. However, maximal exercise caused a shift along the reflex response relationship to a higher CVP and lower FVR. HR baroreflex response (DeltaHR/DeltaMAP) to PE+LBNP+NP was lower (P = 0.015) after maximal exercise (-0.43 +/- 0.15 beats x min-1 x mm Hg-1) compared with the control

  10. Sub-maximal and maximal Yo-Yo intermittent endurance test level 2: heart rate response, reproducibility and application to elite soccer.

    PubMed

    Bradley, Paul S; Mohr, M; Bendiksen, M; Randers, M B; Flindt, M; Barnes, C; Hood, P; Gomez, A; Andersen, Jesper L; Di Mascio, M; Bangsbo, J; Krustrup, P

    2011-06-01

    The aims of this study were to (1) determine the reproducibility of sub-maximal and maximal versions of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2 test), (2) assess the relationship between the Yo-Yo IE2 test and match performance and (3) quantify the sensitivity of the Yo-Yo IE2 test to detect test-retest changes and discriminate between performance for different playing standards and positions in elite soccer. Elite (n = 148) and sub-elite male (n = 14) soccer players carried out the Yo-Yo IE2 test on several occasions over consecutive seasons. Test-retest coefficient of variation (CV) in Yo-Yo IE2 test performance and heart rate after 6 min were 3.9% (n = 37) and 1.4% (n = 32), respectively. Elite male senior and youth U19 players Yo-Yo IE2 performances were better (P < 0.01) than elite youth U16s and sub-elite players (2,603 ± 451 and 2,534 ± 549 vs. 1,855 ± 535 vs. 1,749 ± 382 m). The intra- and inter-season CV for Yo-Yo IE2 test performance were 4.2 and 5.6%, respectively. A correlation was observed (P < 0.05) between Yo-Yo IE2 test performance and the total (r = 0.74) and high-intensity (r = 0.58) running distance covered in a match. A correlation was also evident (P < 0.01) between Yo-Yo IE2 test heart rate after 6 min expressed in percentage of maximal heart rate and the peak values for high-intensity running performed by midfielders in 5-min (r = -0.71), 15-min (r = -0.75) and 45-min periods (r = -0.77). The present data demonstrate that the Yo-Yo IE2 test is reproducible and can be used to determine the capacity of elite soccer players to perform intense intermittent exercise. Furthermore, the Yo-Yo IE2 test was shown to be a sensitive tool that not only relates to match performance but can also differentiate between intermittent exercise performance of players in various standards, stages of the season and playing positions.

  11. Dynamic Control of Maximal Ventricular Elastance in Conscious Dogs Before and After Pacing-Induced Heart Failure

    PubMed Central

    Chen, Xiaoxiao; Sala-Mercado, Javier A.; Hammond, Robert L.; Kim, Jong-Kyung; McDonald, Phillip J.; Stephenson, Larry W.; Soltani, Soroor; O'Leary, Donal S.; Mukkamala, Ramakrishna

    2010-01-01

    We identified the transfer functions relating beat-to-beat fluctuations in arterial blood pressure to maximal ventricular elastance (ABP→Emax) and beat-to-beat fluctuations in heart rate to Emax (HR→Emax) to characterize the dynamic properties of the arterial ventricular contractility baroreflex and force-frequency relation, respectively, in three conscious dogs before and after pacing-induced heart failure. During the control condition, the average gain value, dominant time constant, and time delay were respectively -0.0374 ml-1, 12.8 sec, and 2 sec for the ABP→Emax transfer function and 0.0137 mmHg/ml-bpm, 1.77 sec, and 0 sec for the HR→Emax transfer function. During the heart failure condition, both transfer functions were markedly depressed. These results are consistent with known physiology and previous studies and provide perhaps the first quantitative information on the dynamic control of Emax during normal closed-loop operation. PMID:19963897

  12. Tracking changes in maximal oxygen consumption with the heart rate index in female collegiate soccer players.

    PubMed

    Esco, Michael R; Snarr, Ronald L; Flatt, Andrew; Leatherwood, Matthew; Whittaker, Adam

    2014-09-29

    The purpose of this study was to determine if the HRindex Method (VO2max = [6 x HRindex - 5] x 3.5, where HRindex = HRmax/HRrest) was accurate for tracking changes in VO2max following 8-weeks of endurance training among collegiate female soccer players. Predicted VO2max via the HRindex Method and observed VO2max from a maximal exercise test on a treadmill were determined for a group of female soccer athletes (n = 15) before and following an 8-week endurance training protocol. The predicted (pVO2max) and observed (aVO2max) values were compared at baseline and within 1-week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference between aVO2max before (43.2 ± 2.8 ml·kg·min(-1)) and following (46.2 ± 2.1 ml·kg·min(-1)) the 8-week training program (p < 0.05). However, pVO2max did not significantly change following training (pre = 43.4 ± 4.6 ml·kg·min(-1), post = 42.9 ± 4.1 ml·kg·min(-1), p = 0.53). Furthermore, the correlation between the change in aVO2max and the change in pVO2max was trivial and non-significant (r = 0.30, p = 0.28). The HRindex Method does not appear to be suitable for predicting changes in VO2max following 8-weeks of endurance training in female collegiate soccer players.

  13. Microsimulation Modeling of Coronary Heart Disease: Maximizing the Impact of Nonprofit Hospital-Based Interventions.

    PubMed

    Orenstein, Peggy Vadillo; Shi, Lu

    We use microsimulation to forecast changes in coronary heart disease (CHD) among adults 45 or above over a 20-year time horizon in Los Angeles County (N = 3.4 million), a county with 12 635 CHD deaths in 2010. We simulate individuals' life course and calibrate CHD trends to observed trends in the past. Using the Health Forecasting Community Health Simulation Model, we simulate CHD prevalence and CHD mortality in 2 CHD prevention scenarios: (1) "comprehensive hypertension intervention" and (2) "gradual reduction of the average adult body mass index back to the year 2000 level." We use microsimulation methodology so that nonprofit hospitals can easily use our model to forecast intervention results in their specific hospital catchment area. Our baseline model (without intervention) forecasts an increase in CHD prevalence that will reach 13.01% among those 45+ in Los Angeles County in 2030. Under scenario 1, the increase in CHD prevalence is slower (12.47% in 2030), and the prevalence in scenario 2 reaches 12.83% in 2030. The baseline scenario projects a number of 21 300 CHD deaths in 2030, whereas there will be 20 070 CHD deaths under scenario 1 and 20 970 CHD deaths under scenario 2. At the population level, the CHD mortality outcome, as compared with the metric of CHD prevalence, might be more sensitive to preventive lifestyle interventions. Both CHD prevalence and CHD mortality might be more sensitive to the hypertension intervention than to the obesity reduction in the time horizon of 20 years.

  14. Heart rate recovery after maximal exercise is associated with acetylcholine receptor M2 (CHRM2) gene polymorphism.

    PubMed

    Hautala, Arto J; Rankinen, Tuomo; Kiviniemi, Antti M; Mäkikallio, Timo H; Huikuri, Heikki V; Bouchard, Claude; Tulppo, Mikko P

    2006-07-01

    The determinants of heart rate (HR) recovery after exercise are not well known, although attenuated HR recovery is associated with an increased risk of cardiovascular mortality. Because acetylcholine receptor subtype M2 (CHRM2) plays a key role in the cardiac chronotropic response, we tested the hypothesis that, in healthy individuals, the CHRM2 gene polymorphisms might be associated with HR recovery 1 min after the termination of a maximal exercise test, both before and after endurance training. The study population consisted of sedentary men and women (n = 95, 42 +/- 5 yr) assigned to a training (n = 80) or control group (n = 15). The study subjects underwent a 2-wk laboratory-controlled endurance training program, which included five 40-min sessions/wk at 70-80% of maximal HR. HR recovery differed between the intron 5 rs324640 genotypes at baseline (C/C, -33 +/- 10; C/T, -33 +/- 7; and T/T, -40 +/- 11 beats/min, P = 0.008). Endurance training further strengthened the association: the less common C/C homozygotes showed 6 and 12 beats/min lower HR recovery than the C/T heterozygotes or the T/T homozygotes (P = 0.001), respectively. A similar association was found between A/T transversion at the 3'-untranslated region of the CHRM2 gene and HR recovery at baseline (P = 0.025) and after endurance training (P = 0.005). These data suggest that DNA sequence variation at the CHRM2 locus is a potential modifier of HR recovery in the sedentary state and after short-term endurance training in healthy individuals.

  15. Maximal oxygen uptake is proportional to muscle fiber oxidative capacity, from chronic heart failure patients to professional cyclists.

    PubMed

    van der Zwaard, Stephan; de Ruiter, C Jo; Noordhof, Dionne A; Sterrenburg, Renske; Bloemers, Frank W; de Koning, Jos J; Jaspers, Richard T; van der Laarse, Willem J

    2016-09-01

    V̇o2 max during whole body exercise is presumably constrained by oxygen delivery to mitochondria rather than by mitochondria's ability to consume oxygen. Humans and animals have been reported to exploit only 60-80% of their mitochondrial oxidative capacity at maximal oxygen uptake (V̇o2 max). However, ex vivo quantification of mitochondrial overcapacity is complicated by isolation or permeabilization procedures. An alternative method for estimating mitochondrial oxidative capacity is via enzyme histochemical quantification of succinate dehydrogenase (SDH) activity. We determined to what extent V̇o2 max attained during cycling exercise differs from mitochondrial oxidative capacity predicted from SDH activity of vastus lateralis muscle in chronic heart failure patients, healthy controls, and cyclists. V̇o2 max was assessed in 20 healthy subjects and 28 cyclists, and SDH activity was determined from biopsy cryosections of vastus lateralis using quantitative histochemistry. Similar data from our laboratory of 14 chronic heart failure patients and 6 controls were included. Mitochondrial oxidative capacity was predicted from SDH activity using estimated skeletal muscle mass and the relationship between ex vivo fiber V̇o2 max and SDH activity of isolated single muscle fibers and myocardial trabecula under hyperoxic conditions. Mitochondrial oxidative capacity predicted from SDH activity was related (r(2) = 0.89, P < 0.001) to V̇o2 max measured during cycling in subjects with V̇o2 max ranging from 9.8 to 79.0 ml·kg(-1)·min(-1) V̇o2 max measured during cycling was on average 90 ± 14% of mitochondrial oxidative capacity. We conclude that human V̇o2 max is related to mitochondrial oxidative capacity predicted from skeletal muscle SDH activity. Mitochondrial oxidative capacity is likely marginally limited by oxygen supply to mitochondria.

  16. A novel cardiopulmonary exercise test protocol and criterion to determine maximal oxygen uptake in chronic heart failure

    PubMed Central

    Bowen, T. Scott; Cannon, Daniel T.; Begg, Gordon; Baliga, Vivek; Witte, Klaus K.

    2012-01-01

    Cardiopulmonary exercise testing for peak oxygen uptake (V̇o2peak) can evaluate prognosis in chronic heart failure (CHF) patients, with the peak respiratory exchange ratio (RERpeak) commonly used to confirm maximal effort and maximal oxygen uptake (V̇o2max). We determined the precision of RERpeak in confirming V̇o2max, and whether a novel ramp-incremental (RI) step-exercise (SE) (RISE) test could better determine V̇o2max in CHF. Male CHF patients (n = 24; NYHA class I–III) performed a symptom-limited RISE-95 cycle ergometer test in the format: RI (4–18 W/min; ∼10 min); 5 min recovery (10 W); SE (95% peak RI work rate). Patients (n = 18) then performed RISE-95 tests using slow (3–8 W/min; ∼15 min) and fast (10–30 W/min; ∼6 min) ramp rates. Pulmonary gas exchange was measured breath-by-breath. V̇o2peak was compared within patients by unpaired t-test of the highest 12 breaths during RI and SE phases to confirm V̇o2max and its 95% confidence limits (CI95). RERpeak was significantly influenced by ramp rate (fast, medium, slow: 1.21 ± 0.1 vs. 1.15 ± 0.1 vs. 1.09 ± 0.1; P = 0.001), unlike V̇o2peak (mean n = 18; 14.4 ± 2.6 ml·kg−1·min−1; P = 0.476). Group V̇o2peak was similar between RI and SE (n = 24; 14.5 ± 3.0 vs. 14.7 ± 3.1 ml·kg−1·min−1; P = 0.407); however, within-subject comparisons confirmed V̇o2max in only 14 of 24 patients (CI95 for V̇o2max estimation averaged 1.4 ± 0.8 ml·kg−1·min−1). The RERpeak in CHF was significantly influenced by ramp rate, suggesting its use to determine maximal effort and V̇o2max be abandoned. In contrast, the RISE-95 test had high precision for V̇o2max confirmation with patient-specific CI95 (without secondary criteria), and showed that V̇o2max is commonly underestimated in CHF. The RISE-95 test was well tolerated by CHF patients, supporting its use for V̇o2max confirmation. PMID:22653993

  17. A novel cardiopulmonary exercise test protocol and criterion to determine maximal oxygen uptake in chronic heart failure.

    PubMed

    Bowen, T Scott; Cannon, Daniel T; Begg, Gordon; Baliga, Vivek; Witte, Klaus K; Rossiter, Harry B

    2012-08-01

    Cardiopulmonary exercise testing for peak oxygen uptake (Vo(2peak)) can evaluate prognosis in chronic heart failure (CHF) patients, with the peak respiratory exchange ratio (RER(peak)) commonly used to confirm maximal effort and maximal oxygen uptake (Vo(2max)). We determined the precision of RER(peak) in confirming Vo(2max), and whether a novel ramp-incremental (RI) step-exercise (SE) (RISE) test could better determine Vo(2max) in CHF. Male CHF patients (n = 24; NYHA class I-III) performed a symptom-limited RISE-95 cycle ergometer test in the format: RI (4-18 W/min; ∼10 min); 5 min recovery (10 W); SE (95% peak RI work rate). Patients (n = 18) then performed RISE-95 tests using slow (3-8 W/min; ∼15 min) and fast (10-30 W/min; ∼6 min) ramp rates. Pulmonary gas exchange was measured breath-by-breath. Vo(2peak) was compared within patients by unpaired t-test of the highest 12 breaths during RI and SE phases to confirm Vo(2max) and its 95% confidence limits (CI(95)). RER(peak) was significantly influenced by ramp rate (fast, medium, slow: 1.21 ± 0.1 vs. 1.15 ± 0.1 vs. 1.09 ± 0.1; P = 0.001), unlike Vo(2peak) (mean n = 18; 14.4 ± 2.6 ml·kg(-1)·min(-1); P = 0.476). Group Vo(2peak) was similar between RI and SE (n = 24; 14.5 ± 3.0 vs. 14.7 ± 3.1 ml·kg(-1)·min(-1); P = 0.407); however, within-subject comparisons confirmed Vo(2max) in only 14 of 24 patients (CI(95) for Vo(2max) estimation averaged 1.4 ± 0.8 ml·kg(-1)·min(-1)). The RER(peak) in CHF was significantly influenced by ramp rate, suggesting its use to determine maximal effort and Vo(2max) be abandoned. In contrast, the RISE-95 test had high precision for Vo(2max) confirmation with patient-specific CI(95) (without secondary criteria), and showed that Vo(2max) is commonly underestimated in CHF. The RISE-95 test was well tolerated by CHF patients, supporting its use for Vo(2max) confirmation.

  18. Maximal care considerations when treating patients with end-stage heart failure: ethical and procedural quandaries in management of the very sick.

    PubMed

    Schwarz, Ernst R; Philip, Kiran J; Simsir, Sinan A; Czer, Lawrence; Trento, Alfredo; Finder, Stuart G; Cleenewerck, Laurent A

    2011-12-01

    Deciding who should receive maximal technological treatment options and who should not represents an ethical, moral, psychological and medico-legal challenge for health care providers. Especially in patients with chronic heart failure, the ethical and medico-legal issues associated with providing maximal possible care or withholding the same are coming to the forefront. Procedures, such as cardiac transplantation, have strict criteria for adequate candidacy. These criteria for subsequent listing are based on clinical outcome data but also reflect the reality of organ shortage. Lack of compliance and non-adherence to lifestyle changes represent relative contraindications to heart transplant candidacy. Mechanical circulatory support therapy using ventricular assist devices is becoming a more prominent therapeutic option for patients with end-stage heart failure who are not candidates for transplantation, which also requires strict criteria to enable beneficial outcome for the patient. Physicians need to critically reflect that in many cases, the patient's best interest might not always mean pursuing maximal technological options available. This article reflects on the multitude of critical issues that health care providers have to face while caring for patients with end-stage heart failure.

  19. Effect of acute exercise-induced fatigue on maximal rate of heart rate increase during submaximal cycling.

    PubMed

    Thomson, Rebecca L; Rogers, Daniel K; Howe, Peter R C; Buckley, Jonathan D

    2016-01-01

    Different mathematical models were used to evaluate if the maximal rate of heart rate (HR) increase (rHRI) was related to reductions in exercise performance resulting from acute fatigue. Fourteen triathletes completed testing before and after a 2-h run. rHRI was assessed during 5 min of 100-W cycling and a sigmoidal (rHRIsig) and exponential (rHRIexp) model were applied. Exercise performance was assessed using a 5-min cycling time-trial. The run elicited reductions in time-trial performance (1.34 ± 0.19 to 1.25 ± 0.18 kJ · kg(-1), P < 0.001), rHRIsig (2.25 ± 1.0 to 1.14 ± 0.7 beats · min(-1) · s(-1), P < 0.001) and rHRIexp (3.79 ± 2.07 to 1.98 ± 1.05 beats · min(-1) · s(-1), P = 0.001), and increased pre-exercise HR (73.0 ± 8.4 to 90.5 ± 11.4 beats · min(-1), P < 0.001). Pre-post run difference in time-trial performance was related to difference in rHRIsig (r = 0.58, P = 0.04 and r = 0.75, P = 0.003) but not rHRIexp (r = -0.04, P = 0.9 and r = 0.27, P = 0.4) when controlling for differences in pre-exercise and steady-state HR. rHRIsig was reduced following acute exercise-induced fatigue, and correlated with difference in performance.

  20. Heart Transplant

    MedlinePlus

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  1. Maximal oxygen uptake and exercise tolerance are improved in rats with heart failure subjected to low-level laser therapy associated with resistance training.

    PubMed

    Hentschke, Vítor Scotta; Capalonga, Lucas; Rossato, Douglas Dalcin; Perini, Júlia Luíza; Alves, Jadson Pereira; Stefani, Giuseppe Potrick; Karsten, Marlus; Pontes, Mauro; Lago, Pedro Dal

    2017-01-01

    Exercise tolerance and maximal oxygen uptake (VO2max) are reduced in heart failure (HF). The influence of combined resistance training (RT) and low-level laser therapy (LLLT) on exercise tolerance and VO2max in HF has not yet been explored. The aim of this study was to evaluate the influence of combined RT and LLLT on VO2max and exercise tolerance in rats with HF induced by myocardial infarction (MI). Rats were allocated to sedentary sham (Sed-Sham, n = 12), sedentary heart failure (Sed-HF, n = 9), RT heart failure (RT-HF, n = 7) and RT associated with LLLT heart failure (RT + LLLT-HF, n = 7) groups. After MI or sham surgery, rats underwent a RT and LLLT protocol (applied immediately after RT) for 8 weeks. VO2max and exercise tolerance were evaluated at the end of protocol. HF rats subjected to LLLT combined with RT showed higher VO2basal (41 %), VO2max (40 %), VO2reserve (39 %), run distance (46 %), time to exhaustion (30 %) and maximal velocity (22 %) compared with HF rats that underwent RT alone. LLLT associated with RT improved oxygen uptake and exercise tolerance compared with RT alone in HF rats.

  2. Ratings of Perceived Exertion, Heart Rate, and Power Output in Predicting Maximal Oxygen Uptake During Submaximal Cycle Ergometry.

    ERIC Educational Resources Information Center

    Wilmore, Jack H.; And Others

    1986-01-01

    Sixty-two subjects completed a four-stage submaximal cycle ergometer test to determine if estimates of maximal oxygen uptake could be improved by using ratings of perceived exertion singly or in combination with easily obtainable physiological measures. These procedures could be used to estimate the aerobic power of patients and athletes. (MT)

  3. Maximal oxygen consumption increases with temperature in the European eel (Anguilla anguilla) through increased heart rate and arteriovenous extraction

    PubMed Central

    Claësson, Débora; Wang, Tobias; Malte, Hans

    2016-01-01

    Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel (Anguilla anguilla) together with measurements of cardiac output during rest and activity. Aerobic capacity was not limited by an acutely increased temperature in the European eel. Oxygen demand was met by an increase in heart rate and arteriovenous extraction. These findings suggest that thermal tolerance during exposure to acute temperature changes is not defined by oxygen transport capacity in the eel, and other mechanisms may play a central role in limiting thermal tolerance in these fish. PMID:27766150

  4. Maximal oxygen consumption increases with temperature in the European eel (Anguilla anguilla) through increased heart rate and arteriovenous extraction.

    PubMed

    Claësson, Débora; Wang, Tobias; Malte, Hans

    2016-01-01

    Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel (Anguilla anguilla) together with measurements of cardiac output during rest and activity. Aerobic capacity was not limited by an acutely increased temperature in the European eel. Oxygen demand was met by an increase in heart rate and arteriovenous extraction. These findings suggest that thermal tolerance during exposure to acute temperature changes is not defined by oxygen transport capacity in the eel, and other mechanisms may play a central role in limiting thermal tolerance in these fish.

  5. Heart rates in fire fighters using light and heavy breathing equipment: similar near-maximal exertion in response to multiple work load conditions.

    PubMed

    Manning, J E; Griggs, T R

    1983-03-01

    Intense exertion is an occupational hazard inherent to fire fighting. This study was designed to look at the exertion levels that fire fighters attain during a fire fighting exercise when using (1) no self-contained breathing apparatus (SCBA), (2) light SCBA, and (3) heavy SCBA. Exertion levels were measured as a function of the heart rate increase relative to the maximum predicted heart rate determined by a standard treadmill exercise test. Five fire fighters wore electrocardiographic monitors during a routine fire fighting exercise. Heart rates increased rapidly to 70% to 80% of maximum within the first minute and then plateaued at 90% to 100% until the attack on the fire was completed. There was no significant difference between exertion levels when using no SCBA, light SCBA, and heavy SCBA (split-plot analysis of variance, p greater than .25). These results suggest that fire fighters attain an intense level of physical activity quickly and maintain that level as long as they are actively engaged in fighting fire. These results also suggest that regardless of the weight of the SCBA, if employed, fire fighters exert themselves from 85% to 100% of their maximum and adjust their work output to maintain that near-maximal level.

  6. Time-of-day variation in cardiovascular response to maximal exercise testing in coronary heart disease patients taking a beta-blocker.

    PubMed

    Dufour Doiron, Monique; Prud'homme, Denis; Boulay, Pierre

    2007-08-01

    The aim of this study was to investigate the effect of a beta-blocker (atenolol and metoprolol) on exercise heart rate (HR) and rate pressure product (RPP) during a morning and afternoon maximal exercise test (maxET) in patients with coronary heart disease (CHD). Twenty-one CHD patients (59.9 +/- 8.9 years of age) treated with either atenolol or metoprolol participated in this study. All subjects underwent a morning and afternoon symptom-limited maximal exercise test (maxET) 2-3 h and 8-10 h after medication intake. No significant differences in exercise capacity (atenolol: 8.3 +/- 1.9 vs. 8.3 +/- 2.1 metabolic equivalents (METs); metoprolol: 8.8 +/- 2.0 vs. 8.7 +/- 2.0 METs) or rate of perceived exertion (atenolol: 7.4 +/- 1.9 vs. 7.4 +/- 1.7 METs; metoprolol: 7.2 +/- 1.5 vs. 6.8 +/- 0.9 METs) were observed between the 2 maxETs in either group. However, there was a discrepancy in cardiovascular and ischemic responses between morning and afternoon maxET. Subjects treated with atenolol demonstrated better overall control of HR and RPP during the afternoon maxET. The difference between morning and afternoon HRmax (11 +/- 8 vs. 19 +/- 9 beats.min-1; p = 0.05) was significantly higher in the metoprolol group, but did not attain significance for RPP (31 +/- 30 vs. 54 +/- 28 mmHg.beats.min-1.10-2; p = 0.09). Also, nearly one quarter of our subjects who had a normal morning maxET demonstrated an abnormal electrocardiogram response and (or) ischemia when exercise testing was done in the late afternoon. These changes were more prevalent in subjects taking metoprolol. The results of this study suggest that there is considerable time-of-day variation in the cardiovascular response to a maxET in CHD patients treated with a beta-blocker.

  7. Usefulness of non-invasive measurement of cardiac output during sub-maximal exercise to predict outcome in patients with chronic heart failure.

    PubMed

    Goda, Ayumi; Lang, Chim C; Williams, Paula; Jones, Margaret; Farr, Mary Jane; Mancini, Donna M

    2009-12-01

    Peak oxygen consumption (Vo(2)) is a powerful prognostic predictor of survival in patients with chronic heart failure (CHF) because it provides an indirect assessment of a patient's ability to increase cardiac output (CO). However, many patients with CHF who undergo cardiopulmonary exercise testing are unable to perform maximal exercise. New metabolic carts coupled with the inert gas rebreathing technique provide a noninvasive measurement of CO. Whether the noninvasive measurement of CO at a fixed submaximal workload can predict outcome is unknown. This study's population comprised 259 patients (mean age 54 +/- 14 years, mean left ventricular ejection fraction 27 +/- 14%) with CHF who underwent symptom-limited incremental cardiopulmonary exercise testing. Vo(2) and CO were measured at rest, at 25 W, and at peak exercise. Submaximal exercise was defined as <80% peak Vo(2). Among 259 patients, 145 had Vo(2) at 25 W <80% of peak. Vo(2) at 25 W averaged 9.3 +/- 1.8 ml/kg/min. This Vo(2) represented 62 +/- 11% of peak Vo(2), which averaged 15.4 +/- 4.4 ml/kg/min. Prospective follow-up averaged 521 +/- 337 days. In this cohort, there were 15 outcome events (death, urgent heart transplantation, or implantation of a left ventricular assist device as a bridge to transplantation). On univariate Cox hazard analysis, CO at 25 W (hazard ratio 0.64, 95% confidence interval 0.48 to 0.84, p = 0.002) was found to be significant predictor of events of outcome. In conclusion, CO at 25 W measured noninvasively during submaximal exercise may have potential value as a predictor of outcomes in patients with CHF.

  8. Dynamic control of maximal ventricular elastance via the baroreflex and force-frequency relation in awake dogs before and after pacing-induced heart failure

    PubMed Central

    Chen, Xiaoxiao; Sala-Mercado, Javier A.; Hammond, Robert L.; Ichinose, Masashi; Soltani, Soroor; Mukkamala, Ramakrishna

    2010-01-01

    We investigated to what extent maximal ventricular elastance (Emax) is dynamically controlled by the arterial baroreflex and force-frequency relation in conscious dogs and to what extent these mechanisms are attenuated after the induction of heart failure (HF). We mathematically analyzed spontaneous beat-to-beat hemodynamic variability. First, we estimated Emax for each beat during a baseline period using the ventricular unstressed volume determined with the traditional multiple beat method during vena cava occlusion. We then jointly identified the transfer functions (system gain value and time delay per frequency) relating beat-to-beat fluctuations in arterial blood pressure (ABP) to Emax (ABP→Emax) and beat-to-beat fluctuations in heart rate (HR) to Emax (HR→Emax) to characterize the dynamic properties of the arterial baroreflex and force-frequency relation, respectively. During the control condition, the ABP→Emax transfer function revealed that ABP perturbations caused opposite direction Emax changes with a gain value of −0.023 ± 0.012 ml−1, whereas the HR→Emax transfer function indicated that HR alterations caused same direction Emax changes with a gain value of 0.013 ± 0.005 mmHg·ml−1·(beats/min)−1. Both transfer functions behaved as low-pass filters. However, the ABP→Emax transfer function was more sluggish than the HR→Emax transfer function with overall time constants (indicator of full system response time to a sudden input change) of 11.2 ± 2.8 and 1.7 ± 0.5 s (P < 0.05), respectively. During the HF condition, the ABP→Emax and HR→Emax transfer functions were markedly depressed with gain values reduced to −0.0002 ± 0.007 ml−1 and −0.001 ± 0.004 mmHg·ml−1·(beats/min)−1 (P < 0.1). Emax is rapidly and significantly controlled at rest, but this modulation is virtually abolished in HF. PMID:20435845

  9. Maximal enzyme activities, and myoglobin and glutathione concentrations in heart, liver and skeletal muscle of the Northern Short-tailed shrew (Blarina brevicauda; Insectivora: Soricidae).

    PubMed

    Stewart, J M; Woods, A K; Blakely, J A

    2005-07-01

    We measured the enzymes of glycolysis, Krebs Cycle, beta-oxidation and electron transport in the heart, liver and skeletal muscle of the Northern Short-tailed Shrew, Blarina brevicauda. Additionally, we measured the amount of myoglobin in skeletal and heart muscle as well as the concentration of glutathione in heart. The picture that emerges is of an aerobically well-endowed animal with constrained anaerobic capacity as indicated by small activities of glycolytic enzymes and creatine kinase. Lipid metabolism and amino acid transamination, as well as gluconeogenesis, are predominant in processing carbon resources and probably reflect the large contribution lipid and protein make to the diet of this carnivore. The citrate synthase activity is the largest of any reported value for vertebrate heart (250 U/g). The additional, very active cytochrome c oxidase activity (220 U/g) and large myoglobin concentrations (8 mg/g) in heart are clearly the underpinnings of the rapid metabolic rates reported for small insectivores. The potential for generation of reactive oxygen species must be great since the total glutathione concentration (165 mumol/g) is 300-fold greater in shrew hearts than in hearts of rats.

  10. Age prediction on the basis of brain anatomical measures.

    PubMed

    Valizadeh, S A; Hänggi, J; Mérillat, S; Jäncke, L

    2017-02-01

    In this study, we examined whether age can be predicted on the basis of different anatomical features obtained from a large sample of healthy subjects (n = 3,144). From this sample we obtained different anatomical feature sets: (1) 11 larger brain regions (including cortical volume, thickness, area, subcortical volume, cerebellar volume, etc.), (2) 148 cortical compartmental thickness measures, (3) 148 cortical compartmental area measures, (4) 148 cortical compartmental volume measures, and (5) a combination of the above-mentioned measures. With these anatomical feature sets, we predicted age using 6 statistical techniques (multiple linear regression, ridge regression, neural network, k-nearest neighbourhood, support vector machine, and random forest). We obtained very good age prediction accuracies, with the highest accuracy being R(2)  = 0.84 (prediction on the basis of a neural network and support vector machine approaches for the entire data set) and the lowest being R(2)  = 0.40 (prediction on the basis of a k-nearest neighborhood for cortical surface measures). Interestingly, the easy-to-calculate multiple linear regression approach with the 11 large brain compartments resulted in a very good prediction accuracy (R(2)  = 0.73), whereas the application of the neural network approach for this data set revealed very good age prediction accuracy (R(2)  = 0.83). Taken together, these results demonstrate that age can be predicted well on the basis of anatomical measures. The neural network approach turned out to be the approach with the best results. In addition, it was evident that good prediction accuracies can be achieved using a small but nevertheless age-representative dataset of brain features. Hum Brain Mapp 38:997-1008, 2017. © 2016 Wiley Periodicals, Inc.

  11. The use of Yo-Yo intermittent recovery level 1 and Andersen testing for fitness and maximal heart rate assessments of 6- to 10-year-old school children.

    PubMed

    Bendiksen, Mads; Ahler, Thomas; Clausen, Helle; Wedderkopp, Niels; Krustrup, Peter

    2013-06-01

    We evaluated a submaximal and maximal version of the Yo-Yo intermittent recovery level 1 children's (YYIR1C) test and the Andersen test for fitness and maximal heart rate assessments of children aged 6-10 years. Two repetitions of the YYIR1C and Andersen tests were carried out within 1 week by 6- to 7-year-olds and 8- to 9-year-olds (grade 0, n = 17; grade 2, n = 16) and 6 weeks apart by 9- to 10-year-olds (grade 3, n = 49). Grade 0-2 pupils also performed an incremental treadmill test (ITT). Grade 2 pupils had a better (p < 0.05) YYIR1C (84%; 994 ± 399 m (±SD) vs. 536 ± 218 m) and Andersen test performance (10%; 1,050 ± 71 m vs. 955 ± 56 m) than grade 0 pupils. For grade 0-2 pupils, YYIR1C, Andersen, and ITT peak heart rates were 205 ± 11, 207 ± 9, and 203 ± 7 b·min(-1), respectively (Andersen > ITT, p < 0.05), and for grade 3 pupils, YYIR1C and Andersen peak heart rates were 208 ± 9 and 204 ± 9 b·min(-1), respectively (YYIR1C > Andersen, p < 0.05). Submaximal YYIR1C heart rate (HR) was inversely correlated (p < 0.05) with YYIR1C test performance (r = -0.54 to -0.67) and VO2peak (r = -0.42). The 6-week change in submaximal HR correlated with the change in YYIR1C test performance (r = -0.42 to -0.53, p < 0.05). In conclusion, YYIR1C and Andersen tests are simple and inexpensive intermittent field tests that can detect differences in fitness levels and determine maximal HR of 6- to 10-year-old children. Additionally, submaximal YYIR1C testing can be used for frequent nonexhaustive fitness assessments.

  12. Ultra-weak photon emission of hands in aging prediction.

    PubMed

    Zhao, Xin; van Wijk, Eduard; Yan, Yu; van Wijk, Roeland; Yang, Huanming; Zhang, Yan; Wang, Jian

    2016-09-01

    Aging has been one of the several topics intensely investigated during recent decades. More scientists have been scrutinizing mechanisms behind the human aging process. Ultra-weak photon emission is known as one type of spontaneous photon emission that can be detected with a highly sensitive single photon counting photomultiplier tube (PMT) from the surface of human bodies. It may reflect the body's oxidative damage. Our aim was to examine whether ultra-weak photon emission from a human hand is able to predict one's chronological age. Sixty subjects were recruited and grouped by age. We examined four areas of each hand: palm side of fingers, palm side of hand, dorsum side of fingers, and dorsum side of hand. Left and right hand were measured synchronously with two independent PMTs. Mean strength and Fano factor values of photon counts were utilized to compare the UPE patterns of males and females of different age groups. Subsequently, we utilized UPE data from the most sensitive PMT to develop an age prediction model. We randomly picked 49 subjects to construct the model, whereas the remaining 11 subjects were utilized for validation. The results demonstrated that the model was a good regression compared to the observed values (Pearson's r=0.6, adjusted R square=0.4, p=9.4E-7, accuracy=49/60). Further analysis revealed that the average difference between the chronological age and predicted age was only 7.6±0.8years. It was concluded that this fast and non-invasive photon technology is sufficiently promising to be developed for the estimation of biological aging.

  13. Diurnal Variations in Maximal Oxygen Uptake.

    ERIC Educational Resources Information Center

    McClellan, Powell D.

    A study attempted to determine if diurnal (daily cyclical) variations were present during maximal exercise. The subjects' (30 female undergraduate physical education majors) oxygen consumption and heart rates were monitored while they walked on a treadmill on which the grade was raised every minute. Each subject was tested for maximal oxygen…

  14. Effect of Caffeine on near Maximal Blood Pressure and Blood Pressure Recovery in Physically-Active, College-Aged Females

    PubMed Central

    CONNAHAN, LAURA E.; OTT, CHRISTOPHER A.; BARRY, VAUGHN W.

    2017-01-01

    The purpose of this study is to determine how caffeine affects exercise blood pressure (BP) and active and passive recovery BP after vigorous intensity exercise in physically active college-aged females. Fifteen physically active, ACSM stratified low-risk females (age (y): 23.53 ± 4.07, weight (kg): 60.34 ± 3.67, height (cm): 165.14 ± 7.20, BMI (kg/m2): 22.18 ± 1.55) participated in two Bruce protocol exercise tests. Before each test participants consumed 1) a placebo or 2) 3.3 mg·kg−1 of caffeine at least one hour before exercise in a counterbalanced double-blinded fashion. After reaching 85% of their age-predicted maximum heart rate, BP was taken and participants began an active (i.e. walking) recovery phase for 6 minutes followed by a passive (i.e. sitting) recovery phase. BP was assessed every two minutes in each phase. Recovery times were assessed until active and passive BP equaled 20 mmHg and 10 mmHg above resting, respectively. Participants completed each test 1–2 weeks a part. Maximal systolic and diastolic blood pressures were not significantly different between the two trials. Active recovery, passive recovery, and total recovery times were all significantly longer during the caffeine trial than the placebo trial. Furthermore, the time to reach age-predicted maximum heart rate was significantly shorter in the placebo trial than the caffeine trial. While caffeine consumption did not significantly affect maximal blood pressure, it did affect active and passive recovery time following vigorous intensity exercise in physically active females. Exercise endurance also improved after consuming caffeine in this population. PMID:28344739

  15. Effect of Caffeine on near Maximal Blood Pressure and Blood Pressure Recovery in Physically-Active, College-Aged Females.

    PubMed

    Connahan, Laura E; Ott, Christopher A; Barry, Vaughn W

    2017-01-01

    The purpose of this study is to determine how caffeine affects exercise blood pressure (BP) and active and passive recovery BP after vigorous intensity exercise in physically active college-aged females. Fifteen physically active, ACSM stratified low-risk females (age (y): 23.53 ± 4.07, weight (kg): 60.34 ± 3.67, height (cm): 165.14 ± 7.20, BMI (kg/m(2)): 22.18 ± 1.55) participated in two Bruce protocol exercise tests. Before each test participants consumed 1) a placebo or 2) 3.3 mg·kg(-1) of caffeine at least one hour before exercise in a counterbalanced double-blinded fashion. After reaching 85% of their age-predicted maximum heart rate, BP was taken and participants began an active (i.e. walking) recovery phase for 6 minutes followed by a passive (i.e. sitting) recovery phase. BP was assessed every two minutes in each phase. Recovery times were assessed until active and passive BP equaled 20 mmHg and 10 mmHg above resting, respectively. Participants completed each test 1-2 weeks a part. Maximal systolic and diastolic blood pressures were not significantly different between the two trials. Active recovery, passive recovery, and total recovery times were all significantly longer during the caffeine trial than the placebo trial. Furthermore, the time to reach age-predicted maximum heart rate was significantly shorter in the placebo trial than the caffeine trial. While caffeine consumption did not significantly affect maximal blood pressure, it did affect active and passive recovery time following vigorous intensity exercise in physically active females. Exercise endurance also improved after consuming caffeine in this population.

  16. Heart Health - Brave Heart

    MedlinePlus

    ... Bar Home Current Issue Past Issues Cover Story Heart Health Brave Heart Past Issues / Winter 2009 Table of Contents For ... you can have a good life after a heart attack." Lifestyle Changes Surviving—and thriving—after such ...

  17. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  18. Heart MRI

    MedlinePlus

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

  19. How To: Maximize Google

    ERIC Educational Resources Information Center

    Branzburg, Jeffrey

    2004-01-01

    Google is shaking out to be the leading Web search engine, with recent research from Nielsen NetRatings reporting about 40 percent of all U.S. households using the tool at least once in January 2004. This brief article discusses how teachers and students can maximize their use of Google.

  20. Heart murmurs

    MedlinePlus

    Chest sounds - murmurs; Heart sounds - abnormal; Murmur - innocent; Innocent murmur; Systolic heart murmur; Diastolic heart murmur ... The heart has 4 chambers: Two upper chambers (atria) Two lower chambers (ventricles) The heart has valves that close ...

  1. DNA methylation-based forensic age prediction using artificial neural networks and next generation sequencing.

    PubMed

    Vidaki, Athina; Ballard, David; Aliferi, Anastasia; Miller, Thomas H; Barron, Leon P; Syndercombe Court, Denise

    2017-05-01

    The ability to estimate the age of the donor from recovered biological material at a crime scene can be of substantial value in forensic investigations. Aging can be complex and is associated with various molecular modifications in cells that accumulate over a person's lifetime including epigenetic patterns. The aim of this study was to use age-specific DNA methylation patterns to generate an accurate model for the prediction of chronological age using data from whole blood. In total, 45 age-associated CpG sites were selected based on their reported age coefficients in a previous extensive study and investigated using publicly available methylation data obtained from 1156 whole blood samples (aged 2-90 years) analysed with Illumina's genome-wide methylation platforms (27K/450K). Applying stepwise regression for variable selection, 23 of these CpG sites were identified that could significantly contribute to age prediction modelling and multiple regression analysis carried out with these markers provided an accurate prediction of age (R(2)=0.92, mean absolute error (MAE)=4.6 years). However, applying machine learning, and more specifically a generalised regression neural network model, the age prediction significantly improved (R(2)=0.96) with a MAE=3.3 years for the training set and 4.4 years for a blind test set of 231 cases. The machine learning approach used 16 CpG sites, located in 16 different genomic regions, with the top 3 predictors of age belonged to the genes NHLRC1, SCGN and CSNK1D. The proposed model was further tested using independent cohorts of 53 monozygotic twins (MAE=7.1 years) and a cohort of 1011 disease state individuals (MAE=7.2 years). Furthermore, we highlighted the age markers' potential applicability in samples other than blood by predicting age with similar accuracy in 265 saliva samples (R(2)=0.96) with a MAE=3.2 years (training set) and 4.0 years (blind test). In an attempt to create a sensitive and accurate age prediction test, a next

  2. Telomere dynamics rather than age predict life expectancy in the wild

    PubMed Central

    Bize, Pierre; Criscuolo, François; Metcalfe, Neil B.; Nasir, Lubna; Monaghan, Pat

    2009-01-01

    Despite accumulating evidence from in vitro studies that cellular senescence is linked to telomere dynamics, how this relates to whole-organism senescence and longevity is poorly understood and controversial. Using data on telomere length in red blood cells and long-term survival from wild Alpine swifts of a range of ages, we report that the telomere length and the rate of telomere loss are predictive of life expectancy, and that slow erosion of relatively long telomeres is associated with the highest survival probabilities. Importantly, because telomere dynamics, rather than chronological age, predict life expectancy, our study provides good evidence for a mechanistic link between telomere erosion and reduced organism longevity under natural conditions, chronological age itself possibly not becoming a significant predictor until very old ages beyond those in our sample. PMID:19324831

  3. Quantum-Inspired Maximizer

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2008-01-01

    A report discusses an algorithm for a new kind of dynamics based on a quantum- classical hybrid-quantum-inspired maximizer. The model is represented by a modified Madelung equation in which the quantum potential is replaced by different, specially chosen 'computational' potential. As a result, the dynamics attains both quantum and classical properties: it preserves superposition and entanglement of random solutions, while allowing one to measure its state variables, using classical methods. Such optimal combination of characteristics is a perfect match for quantum-inspired computing. As an application, an algorithm for global maximum of an arbitrary integrable function is proposed. The idea of the proposed algorithm is very simple: based upon the Quantum-inspired Maximizer (QIM), introduce a positive function to be maximized as the probability density to which the solution is attracted. Then the larger value of this function will have the higher probability to appear. Special attention is paid to simulation of integer programming and NP-complete problems. It is demonstrated that the problem of global maximum of an integrable function can be found in polynomial time by using the proposed quantum- classical hybrid. The result is extended to a constrained maximum with applications to integer programming and TSP (Traveling Salesman Problem).

  4. A Maximal Graded Exercise Test to Accurately Predict VO2max in 18-65-Year-Old Adults

    ERIC Educational Resources Information Center

    George, James D.; Bradshaw, Danielle I.; Hyde, Annette; Vehrs, Pat R.; Hager, Ronald L.; Yanowitz, Frank G.

    2007-01-01

    The purpose of this study was to develop an age-generalized regression model to predict maximal oxygen uptake (VO sub 2 max) based on a maximal treadmill graded exercise test (GXT; George, 1996). Participants (N = 100), ages 18-65 years, reached a maximal level of exertion (mean plus or minus standard deviation [SD]; maximal heart rate [HR sub…

  5. Influence of immunologic status on age prediction using signal joint T cell receptor excision circles.

    PubMed

    Cho, Sohee; Seo, Hee Jin; Lee, Ji Hyun; Kim, Moon Young; Lee, Soong Deok

    2017-02-01

    Age estimation based on quantifying signal joint T cell receptor excision circle (sjTREC) in T cells has been established to be a promising approach in forensic practice and demonstrated in different ethnic groups. Considering that the homeostasis of T cells carrying sjTRECs is closely related to the immunologic status of a person, it is important to investigate the influence of various immunologic statuses on the age estimation model. In this study, quantification of sjTREC contents was performed for groups of people with various immune system statuses, and the result showed less correlation with chronological age (r (2) = 0.424) than in the healthy group (r (2) = 0.648). The simulation model indicated that this influence could increase the range of prediction in the age estimation model, and the mean absolute deviation (MAD) between chronological age and predicted age. Through this study, it was demonstrated that immunologic status is a factor that affects the accuracy of age prediction using sjTREC quantification.

  6. A novel strategy for forensic age prediction by DNA methylation and support vector regression model

    PubMed Central

    Xu, Cheng; Qu, Hongzhu; Wang, Guangyu; Xie, Bingbing; Shi, Yi; Yang, Yaran; Zhao, Zhao; Hu, Lan; Fang, Xiangdong; Yan, Jiangwei; Feng, Lei

    2015-01-01

    High deviations resulting from prediction model, gender and population difference have limited age estimation application of DNA methylation markers. Here we identified 2,957 novel age-associated DNA methylation sites (P < 0.01 and R2 > 0.5) in blood of eight pairs of Chinese Han female monozygotic twins. Among them, nine novel sites (false discovery rate < 0.01), along with three other reported sites, were further validated in 49 unrelated female volunteers with ages of 20–80 years by Sequenom Massarray. A total of 95 CpGs were covered in the PCR products and 11 of them were built the age prediction models. After comparing four different models including, multivariate linear regression, multivariate nonlinear regression, back propagation neural network and support vector regression, SVR was identified as the most robust model with the least mean absolute deviation from real chronological age (2.8 years) and an average accuracy of 4.7 years predicted by only six loci from the 11 loci, as well as an less cross-validated error compared with linear regression model. Our novel strategy provides an accurate measurement that is highly useful in estimating the individual age in forensic practice as well as in tracking the aging process in other related applications. PMID:26635134

  7. Maximally Expressive Modeling

    NASA Technical Reports Server (NTRS)

    Jaap, John; Davis, Elizabeth; Richardson, Lea

    2004-01-01

    Planning and scheduling systems organize tasks into a timeline or schedule. Tasks are logically grouped into containers called models. Models are a collection of related tasks, along with their dependencies and requirements, that when met will produce the desired result. One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed; the information sought is at the cutting edge of scientific endeavor; and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a maximally expressive modeling schema.

  8. Maximally Expressive Task Modeling

    NASA Technical Reports Server (NTRS)

    Japp, John; Davis, Elizabeth; Maxwell, Theresa G. (Technical Monitor)

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiment activities for the Space Station. The equipment used in these experiments is some of the most complex hardware ever developed by mankind, the information sought by these experiments is at the cutting edge of scientific endeavor, and the procedures for executing the experiments are intricate and exacting. Scheduling is made more difficult by a scarcity of space station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling space station experiment operations calls for a "maximally expressive" modeling schema. Modeling even the simplest of activities cannot be automated; no sensor can be attached to a piece of equipment that can discern how to use that piece of equipment; no camera can quantify how to operate a piece of equipment. Modeling is a human enterprise-both an art and a science. The modeling schema should allow the models to flow from the keyboard of the user as easily as works of literature flowed from the pen of Shakespeare. The Ground Systems Department at the Marshall Space Flight Center has embarked on an effort to develop a new scheduling engine that is highlighted by a maximally expressive modeling schema. This schema, presented in this paper, is a synergy of technological advances and domain-specific innovations.

  9. COPD: maximization of bronchodilation.

    PubMed

    Nardini, Stefano; Camiciottoli, Gianna; Locicero, Salvatore; Maselli, Rosario; Pasqua, Franco; Passalacqua, Giovanni; Pela, Riccardo; Pesci, Alberto; Sebastiani, Alfredo; Vatrella, Alessandro

    2014-01-01

    The most recent guidelines define COPD in a multidimensional way, nevertheless the diagnosis is still linked to the limitation of airflow, usually measured by the reduction in the FEV1/FVC ratio below 70%. However, the severity of obstruction is not directly correlated to symptoms or to invalidity determined by COPD. Thus, besides respiratory function, COPD should be evaluated based on symptoms, frequency and severity of exacerbations, patient's functional status and health related quality of life (HRQoL). Therapy is mainly aimed at increasing exercise tolerance and reducing dyspnea, with improvement of daily activities and HRQoL. This can be accomplished by a drug-induced reduction of pulmonary hyperinflation and exacerbations frequency and severity. All guidelines recommend bronchodilators as baseline therapy for all stages of COPD, and long-acting inhaled bronchodilators, both beta-2 agonist (LABA) and antimuscarinic (LAMA) drugs, are the most effective in regular treatment in the clinically stable phase. The effectiveness of bronchodilators should be evaluated in terms of functional (relief of bronchial obstruction and pulmonary hyperinflation), symptomatic (exercise tolerance and HRQoL), and clinical improvement (reduction in number or severity of exacerbations), while the absence of a spirometric response is not a reason for interrupting treatment, if there is subjective improvement in symptoms. Because LABA and LAMA act via different mechanisms of action, when administered in combination they can exert additional effects, thus optimizing (i.e. maximizing) sustained bronchodilation in COPD patients with severe airflow limitation, who cannot benefit (or can get only partial benefit) by therapy with a single bronchodilator. Recently, a fixed combination of ultra LABA/LAMA (indacaterol/glycopyrronium) has shown that it is possible to get a stable and persistent bronchodilation, which can help in avoiding undesirable fluctuations of bronchial calibre.

  10. Psychological approach to successful ageing predicts future quality of life in older adults

    PubMed Central

    2011-01-01

    Background Public policies aim to promote well-being, and ultimately the quality of later life. Positive perspectives of ageing are underpinned by a range of appraoches to successful ageing. This study aimed to investigate whether baseline biological, psychological and social aproaches to successful ageing predicted future QoL. Methods Postal follow-up in 2007/8 of a national random sample of 999 people aged 65 and over in 1999/2000. Of 496 valid addresses of survivors at follow-up, the follow-up response rate was 58% (287). Measures of the different concepts of successful ageing were constructed using baseline indicators. They were assessed for their ability to independently predict quality of life at follow-up. Results Few respondents achieved all good scores within each of the approaches to successful ageing. Each approach was associated with follow-up QoL when their scores were analysed continuously. The biomedical (health) approach failed to achieve significance when the traditional dichotomous cut-off point for successfully aged (full health), or not (less than full health), was used. In multiple regression analyses of the relative predictive ability of each approach, only the psychological approach (perceived self-efficacy and optimism) retained significance. Conclusion Only the psychological approach to successful ageing independently predicted QoL at follow-up. Successful ageing is not only about the maintenance of health, but about maximising one's psychological resources, namely self-efficacy and resilience. Increasing use of preventive care, better medical management of morbidity, and changing lifestyles in older people may have beneficial effects on health and longevity, but may not improve their QoL. Adding years to life and life to years may require two distinct and different approaches, one physical and the other psychological. Follow-up health status, number of supporters and social activities, and self-rated active ageing also significantly

  11. Heart Failure

    MedlinePlus

    Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Heart failure does not mean that your heart has stopped ... Tiredness and shortness of breath Common causes of heart failure are coronary artery disease, high blood pressure and ...

  12. Heart attack

    MedlinePlus

    ... infarction; Non-ST - elevation myocardial infarction; NSTEMI; CAD - heart attack; Coronary artery disease - heart attack ... made up of cholesterol and other cells. A heart attack may occur when: A tear in the ...

  13. Heart palpitations

    MedlinePlus

    ... occur. Try deep relaxation or breathing exercises. Practice yoga, meditation, or tai chi. Get regular exercise. Do ... M. Editorial team. Images Heart chambers Heart beat Yoga Arrhythmia Read more Atrial Fibrillation Read more Heart ...

  14. Height loss starting in middle age predicts increased mortality in the elderly.

    PubMed

    Masunari, Naomi; Fujiwara, Saeko; Kasagi, Fumiyoshi; Takahashi, Ikuno; Yamada, Michiko; Nakamura, Toshitaka

    2012-01-01

    The purpose of this study was to determine the mortality risk among Japanese men and women with height loss starting in middle age, taking into account lifestyle and physical factors. A total of 2498 subjects (755 men and 1743 women) aged 47 to 91 years old underwent physical examinations during the period 1994 to 1995. Those individuals were followed for mortality status through 2003. Mortality risk was estimated using an age-stratified Cox proportional hazards model. In addition to sex, adjustment factors such as radiation dose, lifestyle, and physical factors measured at the baseline--including smoking status, alcohol intake, total cholesterol, blood pressure, and diagnosed diseases--were used for analysis of total mortality and mortality from each cause of death. There were a total of 302 all-cause deaths, 46 coronary heart disease and stroke deaths, 58 respiratory deaths including 45 pneumonia deaths, and 132 cancer deaths during the follow-up period. Participants were followed for 20,787 person-years after baseline. Prior history of vertebral deformity and hip fracture were not associated with mortality risk. However, more than 2 cm of height loss starting in middle age showed a significant association with all-cause mortality among the study participants (HR = 1.76, 95% CI 1.31 to 2.38, p = 0.0002), after adjustment was made for sex, attained age, atomic-bomb radiation exposure, and lifestyle and physical factors. Such height loss also was significantly associated with death due to coronary heart disease or stroke (HR = 3.35, 95% CI 1.63 to 6.86, p = 0.0010), as well as respiratory-disease death (HR = 2.52, 95% CI 1.25 to 5.22, p = 0.0130), but not cancer death. Continuous HL also was associated with all-cause mortality and CHD- or stroke-caused mortality. Association between height loss and mortality was still significant, even after excluding persons with vertebral deformity. Height loss of more than 2 cm starting in middle age

  15. Heart Transplantation

    MedlinePlus

    A heart transplant removes a damaged or diseased heart and replaces it with a healthy one. The healthy heart comes from a donor who has died. It is the last resort for people with heart failure when all other treatments have failed. The ...

  16. Heart Diseases

    MedlinePlus

    ... you're like most people, you think that heart disease is a problem for others. But heart disease is the number one killer in the ... of disability. There are many different forms of heart disease. The most common cause of heart disease ...

  17. Evaluation of true maximal oxygen uptake based on a novel set of standardized criteria.

    PubMed

    Midgley, Adrian W; Carroll, Sean; Marchant, David; McNaughton, Lars R; Siegler, Jason

    2009-04-01

    In this study, criteria are used to identify whether a subject has elicited maximal oxygen uptake. We evaluated the validity of traditional maximal oxygen uptake criteria and propose a novel set of criteria. Twenty athletes completed a maximal oxygen uptake test, consisting of an incremental phase and a subsequent supramaximal phase to exhaustion (verification phase). Traditional and novel maximal oxygen uptake criteria were evaluated. Novel criteria were: oxygen uptake plateau defined as the difference between modelled and actual maximal oxygen uptake >50% of the regression slope of the individual oxygen uptake-workrate relationship; as in the first criterion, but for maximal verification oxygen uptake; and a difference of maximal heart rate values in the 2 phases. Satisfying the traditional oxygen uptake plateau criterion was largely an artefact of the between-subject variation in the oxygen uptake-workrate relationship. Secondary criteria, supposedly an indicator of maximal effort, were often satisfied long before volitional exhaustion, even at intensities as low as 61% maximal oxygen uptake. No significant mean differences were observed between the incremental and verification phases for oxygen uptake (t = 0.4; p = 0.7) or heart rate (t = 0.8; p = 0.5). The novel oxygen uptake plateau criterion, maximal oxygen uptake verification criterion, and maximal heart rate verification criterion were satisfied by 17, 18, and 18 subjects, respectively. The small individual absolute differences in oxygen uptake between incremental and verification phases observed in most subjects provided additional confidence that maximal oxygen uptake was elicited. Current maximal oxygen uptake criteria were not valid and novel criteria should be further explored.

  18. Examination of DNA methylation status of the ELOVL2 marker may be useful for human age prediction in forensic science.

    PubMed

    Zbieć-Piekarska, Renata; Spólnicka, Magdalena; Kupiec, Tomasz; Makowska, Żanetta; Spas, Anna; Parys-Proszek, Agnieszka; Kucharczyk, Krzysztof; Płoski, Rafał; Branicki, Wojciech

    2015-01-01

    Age estimation in forensic investigations may complement the prediction of externally visible characteristics and the inference of biogeographical ancestry, thus allowing a better description of an unknown individual. Multiple CpG sites that show linear correlation between age and degree of DNA methylation have been identified in the human genome, providing a selection of candidates for age prediction. In this study, we optimized an assay based on bisulfite conversion and pyrosequencing of 7 CpG sites located in the ELOVL2 gene. Examination of 303 blood samples collected from individuals aged 2-75 years allowed selection of the most informative site, explaining 83% of variation in age. The final linear regression model included two CpG sites in ELOVL2 and enabled age prediction with R(2)=0.859, prediction error=6.85 and mean absolute deviation MAD=5.03. Examination of a testing set of 124 blood samples (MAD=5.75) showed that 68.5% of samples were correctly predicted, assuming that chronological and predicted ages matched ± 7 years. It was found that the ELOVL2 methylation status in bloodstains had not changed significantly after 4 weeks of storage in room temperature conditions. Analysis of 45 bloodstains deposited on tissue paper after 5, 10 and 15 years of storage in room conditions indicated that although a gradual decrease of positive PCR results was observed, the general age prediction success rate remained similar and equaled 60-78%. The obtained results show that the ELOVL2 locus provides a very good source of information about human chronological age based on analysis of blood, including bloodstains, and it may constitute a powerful and reliable predictor in future forensic age estimation models.

  19. Who gets a heart? Rationing and rationalizing in heart transplantation.

    PubMed Central

    Allen, M D; Fishbein, D P; McBride, M; Ellison, M; Daily, O P

    1997-01-01

    National policy on organ transplantation is made by the United Network for Organ Sharing (UNOS), a representative body composed of health care professionals and patients. Standardized criteria for determining when a patient should be placed on the waiting list for heart transplantation are now in effect nationwide. Current and future directions to maximize the utilization of available donated organs are explored. PMID:9217435

  20. ST segment/heart rate slope as a predictor of coronary artery disease: comparison with quantitative thallium imaging and conventional ST segment criteria

    SciTech Connect

    Finkelhor, R.S.; Newhouse, K.E.; Vrobel, T.R.; Miron, S.D.; Bahler, R.C.

    1986-08-01

    The ST segment shift relative to exercise-induced increments in heart rate, the ST/heart rate slope (ST/HR slope), has been proposed as a more accurate ECG criterion for diagnosing significant coronary artery disease (CAD). Its clinical utility, with the use of a standard treadmill protocol, was compared with quantitative stress thallium (TI) and standard treadmill criteria in 64 unselected patients who underwent coronary angiography. The overall diagnostic accuracy of the ST/HR slope was an improvement over TI and conventional ST criteria (81%, 67%, and 69%). For patients failing to reach 85% of their age-predicted maximal heart rate, its diagnostic accuracy was comparable with TI (77% and 74%). Its sensitivity in patients without prior myocardial infarctions was equivalent to that of thallium (91% and 95%). The ST/HR slope was directly related to the angiographic severity (Gensini score) of CAD in patients without a prior infarction (r = 0.61, p less than 0.001). The ST/HR slope was an improved ECG criterion for diagnosing CAD and compared favorably with TI imaging.

  1. Cardiovascular consequences of bed rest: effect on maximal oxygen uptake

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.

    1997-01-01

    Maximal oxygen uptake (VO2max) is reduced in healthy individuals confined to bed rest, suggesting it is independent of any disease state. The magnitude of reduction in VO2max is dependent on duration of bed rest and the initial level of aerobic fitness (VO2max), but it appears to be independent of age or gender. Bed rest induces an elevated maximal heart rate which, in turn, is associated with decreased cardiac vagal tone, increased sympathetic catecholamine secretion, and greater cardiac beta-receptor sensitivity. Despite the elevation in heart rate, VO2max is reduced primarily from decreased maximal stroke volume and cardiac output. An elevated ejection fraction during exercise following bed rest suggests that the lower stroke volume is not caused by ventricular dysfunction but is primarily the result of decreased venous return associated with lower circulating blood volume, reduced central venous pressure, and higher venous compliance in the lower extremities. VO2max, stroke volume, and cardiac output are further compromised by exercise in the upright posture. The contribution of hypovolemia to reduced cardiac output during exercise following bed rest is supported by the close relationship between the relative magnitude (% delta) and time course of change in blood volume and VO2max during bed rest, and also by the fact that retention of plasma volume is associated with maintenance of VO2max after bed rest. Arteriovenous oxygen difference during maximal exercise is not altered by bed rest, suggesting that peripheral mechanisms may not contribute significantly to the decreased VO2max. However reduction in baseline and maximal muscle blood flow, red blood cell volume, and capillarization in working muscles represent peripheral mechanisms that may contribute to limited oxygen delivery and, subsequently, lowered VO2max. Thus, alterations in cardiac and vascular functions induced by prolonged confinement to bed rest contribute to diminution of maximal oxygen uptake

  2. Heart pacemaker

    MedlinePlus

    ... PA: Elsevier Saunders; 2015:chap 37. Swerdlow CD, Wang PJ, Zipes DP. Pacemakers and implantable cardioverter-defibrillators. ... and lifestyle Controlling your high blood pressure Dietary fats explained Fast food tips Heart attack - discharge Heart ...

  3. Heart Block

    MedlinePlus

    ... not used to treat first-degree heart block. All types of heart block may increase your risk for other arrhythmias, such as atrial fibrillation (A-tre-al fih-brih-LA-shun). Talk with your doctor ...

  4. Heart Attack

    MedlinePlus

    ... a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get ... It's important to know the symptoms of a heart attack and call 9-1-1 if someone ...

  5. Automated pediatric abdominal effective diameter measurements versus age-predicted body size for normalization of CT dose.

    PubMed

    Cheng, Phillip M; Vachon, Linda A; Duddalwar, Vinay A

    2013-12-01

    There has been increasing interest in adjusting CT radiation dose data for patient body size. A method for automated computation of the abdominal effective diameter of a patient from a CT image has previously only been tested in adult patients. In this work, we tested the method on a set of 128 pediatric patients aged 0.8 to 12.9 years (average 8.0 years, SD = 3.7 years) who had CT abdomen/pelvis exams performed on a Toshiba Aquilion 64 scanner. For this set of patients, age-predicted abdominal effective diameter extrapolated based on data from the International Commission on Radiation Units and Measurements was a relatively poor predictor of measured effective diameter. The mean absolute percentage error between the CTDI normalization coefficient calculated from a manually measured effective diameter and the coefficient determined by age-predicted effective diameter was 12.3 % with respect to a 32 cm phantom (range 0.0-52.8 %, SD 8.7 %) and 12.9 % with respect to a 16 cm phantom (range 0.0-56.4 %, SD 9.2 %). In contrast, there is a close correspondence between the automated and manually measured patient effective diameters, with a mean absolute error of 0.6 cm (error range 0.2-1.3 cm). This correspondence translates into a high degree of correspondence between normalization coefficients determined by automated and manual measurements; the mean absolute percentage error was 2.1 % with respect to a 32 cm phantom (range 0.0-8.1 %, SD = 1.4 %) and 2.3 % with respect to a 16 cm phantom (range 0.0-9.3 %, SD = 1.6 %).

  6. Maximization, learning, and economic behavior

    PubMed Central

    Erev, Ido; Roth, Alvin E.

    2014-01-01

    The rationality assumption that underlies mainstream economic theory has proved to be a useful approximation, despite the fact that systematic violations to its predictions can be found. That is, the assumption of rational behavior is useful in understanding the ways in which many successful economic institutions function, although it is also true that actual human behavior falls systematically short of perfect rationality. We consider a possible explanation of this apparent inconsistency, suggesting that mechanisms that rest on the rationality assumption are likely to be successful when they create an environment in which the behavior they try to facilitate leads to the best payoff for all agents on average, and most of the time. Review of basic learning research suggests that, under these conditions, people quickly learn to maximize expected return. This review also shows that there are many situations in which experience does not increase maximization. In many cases, experience leads people to underweight rare events. In addition, the current paper suggests that it is convenient to distinguish between two behavioral approaches to improve economic analyses. The first, and more conventional approach among behavioral economists and psychologists interested in judgment and decision making, highlights violations of the rational model and proposes descriptive models that capture these violations. The second approach studies human learning to clarify the conditions under which people quickly learn to maximize expected return. The current review highlights one set of conditions of this type and shows how the understanding of these conditions can facilitate market design. PMID:25024182

  7. Maximization, learning, and economic behavior.

    PubMed

    Erev, Ido; Roth, Alvin E

    2014-07-22

    The rationality assumption that underlies mainstream economic theory has proved to be a useful approximation, despite the fact that systematic violations to its predictions can be found. That is, the assumption of rational behavior is useful in understanding the ways in which many successful economic institutions function, although it is also true that actual human behavior falls systematically short of perfect rationality. We consider a possible explanation of this apparent inconsistency, suggesting that mechanisms that rest on the rationality assumption are likely to be successful when they create an environment in which the behavior they try to facilitate leads to the best payoff for all agents on average, and most of the time. Review of basic learning research suggests that, under these conditions, people quickly learn to maximize expected return. This review also shows that there are many situations in which experience does not increase maximization. In many cases, experience leads people to underweight rare events. In addition, the current paper suggests that it is convenient to distinguish between two behavioral approaches to improve economic analyses. The first, and more conventional approach among behavioral economists and psychologists interested in judgment and decision making, highlights violations of the rational model and proposes descriptive models that capture these violations. The second approach studies human learning to clarify the conditions under which people quickly learn to maximize expected return. The current review highlights one set of conditions of this type and shows how the understanding of these conditions can facilitate market design.

  8. Ischemic preconditioning of the muscle improves maximal exercise performance but not maximal oxygen uptake in humans.

    PubMed

    Crisafulli, Antonio; Tangianu, Flavio; Tocco, Filippo; Concu, Alberto; Mameli, Ombretta; Mulliri, Gabriele; Caria, Marcello A

    2011-08-01

    Brief episodes of nonlethal ischemia, commonly known as "ischemic preconditioning" (IP), are protective against cell injury induced by infarction. Moreover, muscle IP has been found capable of improving exercise performance. The aim of the study was the comparison of standard exercise performances carried out in normal conditions with those carried out following IP, achieved by brief muscle ischemia at rest (RIP) and after exercise (EIP). Seventeen physically active, healthy male subjects performed three incremental, randomly assigned maximal exercise tests on a cycle ergometer up to exhaustion. One was the reference (REF) test, whereas the others were performed after the RIP and EIP sessions. Total exercise time (TET), total work (TW), and maximal power output (W(max)), oxygen uptake (VO(2max)), and pulmonary ventilation (VE(max)) were assessed. Furthermore, impedance cardiography was used to measure maximal heart rate (HR(max)), stroke volume (SV(max)), and cardiac output (CO(max)). A subgroup of volunteers (n = 10) performed all-out tests to assess their anaerobic capacity. We found that both RIP and EIP protocols increased in a similar fashion TET, TW, W(max), VE(max), and HR(max) with respect to the REF test. In particular, W(max) increased by ∼ 4% in both preconditioning procedures. However, preconditioning sessions failed to increase traditionally measured variables such as VO(2max), SV(max,) CO(max), and anaerobic capacity(.) It was concluded that muscle IP improves performance without any difference between RIP and EIP procedures. The mechanism of this effect could be related to changes in fatigue perception.

  9. Heart regeneration.

    PubMed

    Breckwoldt, Kaja; Weinberger, Florian; Eschenhagen, Thomas

    2016-07-01

    Regenerating an injured heart holds great promise for millions of patients suffering from heart diseases. Since the human heart has very limited regenerative capacity, this is a challenging task. Numerous strategies aiming to improve heart function have been developed. In this review we focus on approaches intending to replace damaged heart muscle by new cardiomyocytes. Different strategies for the production of cardiomyocytes from human embryonic stem cells or human induced pluripotent stem cells, by direct reprogramming and induction of cardiomyocyte proliferation are discussed regarding their therapeutic potential and respective advantages and disadvantages. Furthermore, different methods for the transplantation of pluripotent stem cell-derived cardiomyocytes are described and their clinical perspectives are discussed. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  10. Hypoplastic left heart syndrome

    MedlinePlus

    HLHS; Congenital heart - hypoplastic left heart; Cyanotic heart disease - hypoplastic left heart ... Hypoplastic left heart is a rare type of congenital heart disease. It is more common in males than in females. As ...

  11. Multivariate residues and maximal unitarity

    NASA Astrophysics Data System (ADS)

    Søgaard, Mads; Zhang, Yang

    2013-12-01

    We extend the maximal unitarity method to amplitude contributions whose cuts define multidimensional algebraic varieties. The technique is valid to all orders and is explicitly demonstrated at three loops in gauge theories with any number of fermions and scalars in the adjoint representation. Deca-cuts realized by replacement of real slice integration contours by higher-dimensional tori encircling the global poles are used to factorize the planar triple box onto a product of trees. We apply computational algebraic geometry and multivariate complex analysis to derive unique projectors for all master integral coefficients and obtain compact analytic formulae in terms of tree-level data.

  12. Heart transplant

    MedlinePlus

    ... catheterization Tests to look for cancer Tissue and blood typing , to help make sure your body will not reject the donated heart Ultrasound of your neck and legs You will ... heart pump enough blood to the body. Most often, this is a ...

  13. Heart Anatomy

    MedlinePlus

    ... español An Incredible Machine Bonus poster (PDF) The Human Heart Anatomy Blood The Conduction System The Coronary Arteries The Heart Valves The Heartbeat Vasculature of the Arm Vasculature of the Head Vasculature of the Leg Vasculature of the Torso ...

  14. Maximal aerobic power measurement in runners and swimmers.

    PubMed Central

    Corry, I.; Powers, N.

    1982-01-01

    Five cross-country runners and five competitive swimmers performed a pulling exercise with elastic shock cords and a treadmill run to exhaustion. The mean VO2 max related to lean body mass of the runners was significantly higher than the swimmers on the treadmill (p less than 0.05) while, on the pulling test, the mean VO2 max of the swimmers was significantly higher than the runners (p less 0.01). The maximum heart rates achieved pulling were 95% of the running maximum by runners and 96% by swimmers with no significant difference between them. Their mean oxygen pulse was almost the same for maximal running but the swimmers had a significantly higher oxygen pulse than the runners for maximal pulling (p less than 0.01). The swimmers could reach about 79% of their running VO2 max by pulling while the runners used 53% of their running VO2 max. Images Fig. 1 Fig. 3 PMID:7139226

  15. Knowledge discovery by accuracy maximization

    PubMed Central

    Cacciatore, Stefano; Luchinat, Claudio; Tenori, Leonardo

    2014-01-01

    Here we describe KODAMA (knowledge discovery by accuracy maximization), an unsupervised and semisupervised learning algorithm that performs feature extraction from noisy and high-dimensional data. Unlike other data mining methods, the peculiarity of KODAMA is that it is driven by an integrated procedure of cross-validation of the results. The discovery of a local manifold’s topology is led by a classifier through a Monte Carlo procedure of maximization of cross-validated predictive accuracy. Briefly, our approach differs from previous methods in that it has an integrated procedure of validation of the results. In this way, the method ensures the highest robustness of the obtained solution. This robustness is demonstrated on experimental datasets of gene expression and metabolomics, where KODAMA compares favorably with other existing feature extraction methods. KODAMA is then applied to an astronomical dataset, revealing unexpected features. Interesting and not easily predictable features are also found in the analysis of the State of the Union speeches by American presidents: KODAMA reveals an abrupt linguistic transition sharply separating all post-Reagan from all pre-Reagan speeches. The transition occurs during Reagan’s presidency and not from its beginning. PMID:24706821

  16. [Normal or high maximal oxygen uptake: a target in health].

    PubMed

    Ben-Dov, Issahar; Segel, Michael

    2012-02-01

    To achieve the predicted maximal oxygen consumption, many organs need to increase their output in a synchronized fashion. Therefore, maximal oxygen consumption is the single most reliable parameter predicting fitness, morbidity and mortality. Peak O2 uptake can be measured from noninvasive ventilatory parameters during short, incremental, cardiopulmonary exercise test (CPET) on a cycle ergometer or on a treadmill. Commercial systems are available and all enable breath by breath measurement of ventilation, exhaled gas concentration, oxygen saturation and additional cardiorespiratory parameters. Performance of the test requires adherence to strict guidelines and experienced technicians and physicians, although their qualification has not yet been defined by the national health authorities. There are well defined indications and benefits from CPET, among them are, determination of the anaerobic threshold, defining the cause of dyspnea, the timing for heart transplantation, exercise prescription for training and rehabilitation purposes and follow-up on disease progression or response to pharmacological or other modes of therapy. Measuring maximal oxygen consumption should be encouraged in health and disease and normal maximal oxygen consumption should be defined as a health target.

  17. Natural selection maximizes Fisher information.

    PubMed

    Frank, S A

    2009-02-01

    In biology, information flows from the environment to the genome by the process of natural selection. However, it has not been clear precisely what sort of information metric properly describes natural selection. Here, I show that Fisher information arises as the intrinsic metric of natural selection and evolutionary dynamics. Maximizing the amount of Fisher information about the environment captured by the population leads to Fisher's fundamental theorem of natural selection, the most profound statement about how natural selection influences evolutionary dynamics. I also show a relation between Fisher information and Shannon information (entropy) that may help to unify the correspondence between information and dynamics. Finally, I discuss possible connections between the fundamental role of Fisher information in statistics, biology and other fields of science.

  18. Wine and heart health

    MedlinePlus

    Health and wine; Wine and heart disease; Preventing heart disease - wine; Preventing heart disease - alcohol ... more often just to lower your risk of heart disease. Heavier drinking can harm the heart and ...

  19. What Causes Heart Failure?

    MedlinePlus

    ... Topics Arrhythmia Congenital Heart Defects Coronary Heart Disease Heart Valve Disease High Blood Pressure Send a link to NHLBI ... with the heart’s structure are present at birth. Heart valve disease . Occurs if one or more of your heart ...

  20. What Is Heart Failure?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Heart Failure? Heart failure is a condition in which the heart can' ... force. Some people have both problems. The term "heart failure" doesn't mean that your heart has stopped ...

  1. Factors associated with the differential in actual gestational age and gestational age predicted from transrectal ultrasonography in pregnant dairy cows.

    PubMed

    Fitzgerald, A M; Ryan, D P; Berry, D P

    2015-08-01

    The objective of the study was to determine (1) how gestational age predicted using transrectal ultrasonography related to actual gestational age derived as the number of days from the most recent artificial insemination date, (2) what factors, if any, were associated with the differential between the two measures, and (3) the association between this differential in gestational age and the likelihood of subsequent pregnancy loss, stillbirth, or calving dystocia. The data set contained 7340 ultrasound records from 6805 Holstein Friesian dairy cows in 175 herds. Ultrasonography assessment underestimated gestational age relative to days since last service by 0.51 days (standard error [SE]: 0.040), although the differential was less during embryonic development phase (i.e., ≤42 days of gestation; mean overestimation of 0.31 days) versus fetal development phase (i.e., >42 days of gestation; mean underestimation of 0.81 days). Predicted calving date calculated from ultrasonography was 1.41 days (SE: 0.040) later than the actual subsequent calving date and was, on average, 0.52 days later than predicted calving date, assuming a gestation length of 282 days. Parity of the dam (P < 0.05), stage of pregnancy (P < 0.001), and sex of the calf born (P < 0.001) were all associated with the differential in gestational age based on ultrasonography versus days since last service. No obvious trend among parities was evident in the difference between the methods in predicting gestational age. Ultrasonography underestimated gestational age by 0.83 (SE: 0.15) days in parity 5+ cows and underestimated gestational age by 0.41 (SE: 0.14) days in the first-parity cows. Relative to gestational age predicted from the most recent service, ultrasonography underestimated gestational age by 0.75 (SE: 0.13) days for heifer fetuses and underestimated gestational age by 0.36 (SE: 0.13) days for bull fetuses. The heritability of the differential in gestational age between the methods of

  2. Heart Attack

    MedlinePlus

    ... yourself MedlinePlus for More Information National Institute on Aging Related Topics Heart Failure High Blood Cholesterol High ... us | Customer Support | site map National Institute on Aging | U.S. National Library of Medicine | National Institutes of ...

  3. Hearts Wish.

    ERIC Educational Resources Information Center

    Jones, Lethonee A.

    1989-01-01

    Investigates characteristics and themes in 102 drawings by sexually abused children. Themes of the drawings included genitalia, the absence of specific body parts, phallic symbols, inappropriate smiles, distorted body images, kinetic activity, prominent hands and fingers, and hearts. (RJC)

  4. Heart Failure

    MedlinePlus

    ... for people who can't tolerate ACE inhibitors. Beta blockers. This class of drugs not only slows your ... rhythms and lessen your chance of dying unexpectedly. Beta blockers may reduce signs and symptoms of heart failure, ...

  5. Spatial-Sequential Working Memory in Younger and Older Adults: Age Predicts Backward Recall Performance within Both Age Groups.

    PubMed

    Brown, Louise A

    2016-01-01

    Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18-40 years) and older (64-85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale - Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts

  6. Spatial-Sequential Working Memory in Younger and Older Adults: Age Predicts Backward Recall Performance within Both Age Groups

    PubMed Central

    Brown, Louise A.

    2016-01-01

    Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18–40 years) and older (64–85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale – Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts

  7. Effects of selective cooling of the facial area on physiological and metabolic output during graded maximal or prolonged submaximal exercise

    NASA Astrophysics Data System (ADS)

    Quirion, A.; Boisvert, P.; Brisson, G. R.; Decarufel, D.; Laurencelle, L.; Dulac, S.; Vogelaere, P.; Therminarias, A.

    1989-06-01

    Physiological and metabolic output responses to facial cooling during a graded maximal exercise and a prolonged submaximal exercise lasting 30 min at 65%dot VO_2 max were investigated in five male subjects. Pedalling on a cycle ergometer was performed both with and without facial cooling (10°C, 4.6 m s-1). Facial cooling at the end of graded maximal exercise apparently had no effect on plasma lactate (LA), maximal oxygen consumption (dot VO_2 max), maximal heart rate (HR max), rectal temperature ( T re), work-load, lactate threshold (LT), ventilatory threshold (VT) and onset of blood lactate accumulation (OBLA). However, the response to facial cooling after prolonged submaximal exercise is significantly different for heart rate and work-load. The results suggest that facial wind stimulation during maximal exercise does not produce a stress high enough to alter the metabolic and physiological responses.

  8. What Is a Heart Murmur?

    MedlinePlus

    ... Heart Murmur Related Topics Anemia Congenital Heart Defects Heart Valve Disease Holes in the Heart How the Heart Works ... heart defect that is present since birth or heart valve disease. Depending on the heart problem causing the abnormal ...

  9. Maximal dinucleotide and trinucleotide circular codes.

    PubMed

    Michel, Christian J; Pellegrini, Marco; Pirillo, Giuseppe

    2016-01-21

    We determine here the number and the list of maximal dinucleotide and trinucleotide circular codes. We prove that there is no maximal dinucleotide circular code having strictly less than 6 elements (maximum size of dinucleotide circular codes). On the other hand, a computer calculus shows that there are maximal trinucleotide circular codes with less than 20 elements (maximum size of trinucleotide circular codes). More precisely, there are maximal trinucleotide circular codes with 14, 15, 16, 17, 18 and 19 elements and no maximal trinucleotide circular code having less than 14 elements. We give the same information for the maximal self-complementary dinucleotide and trinucleotide circular codes. The amino acid distribution of maximal trinucleotide circular codes is also determined.

  10. Physiologic Responses of Able-Bodied and Paraplegic Males to Maximal Arm Ergometry.

    ERIC Educational Resources Information Center

    Israel, Richard G.; And Others

    A study compared physiologic responses of healthy paraplegic males to those of healthy, able-bodied males during maximal arm ergometry. Fifteen able-bodied, healthy adult males and 13 healthy adult male paraplegics followed an exercise program involving heart rate, increased exercise loads, and oxygen uptake. Results from an analysis of the data…

  11. A maximally supersymmetric Kondo model

    NASA Astrophysics Data System (ADS)

    Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo

    2012-10-01

    We study the maximally supersymmetric Kondo model obtained by adding a fermionic impurity to N=4 supersymmetric Yang-Mills theory. While the original Kondo problem describes a defect interacting with a free Fermi liquid of itinerant electrons, here the ambient theory is an interacting CFT, and this introduces qualitatively new features into the system. The model arises in string theory by considering the intersection of a stack of M D5-branes with a stack of N D3-branes, at a point in the D3 worldvolume. We analyze the theory holographically, and propose a dictionary between the Kondo problem and antisymmetric Wilson loops in N=4 SYM. We perform an explicit calculation of the D5 fluctuations in the D3 geometry and determine the spectrum of defect operators. This establishes the stability of the Kondo fixed point together with its basic thermodynamic properties. Known supergravity solutions for Wilson loops allow us to go beyond the probe approximation: the D5s disappear and are replaced by three-form flux piercing a new topologically non-trivial S3 in the corrected geometry. This describes the Kondo model in terms of a geometric transition. A dual matrix model reflects the basic properties of the corrected gravity solution in its eigenvalue distribution.

  12. Maximizing the optical network capacity

    PubMed Central

    Bayvel, Polina; Maher, Robert; Liga, Gabriele; Shevchenko, Nikita A.; Lavery, Domaniç; Killey, Robert I.

    2016-01-01

    Most of the digital data transmitted are carried by optical fibres, forming the great part of the national and international communication infrastructure. The information-carrying capacity of these networks has increased vastly over the past decades through the introduction of wavelength division multiplexing, advanced modulation formats, digital signal processing and improved optical fibre and amplifier technology. These developments sparked the communication revolution and the growth of the Internet, and have created an illusion of infinite capacity being available. But as the volume of data continues to increase, is there a limit to the capacity of an optical fibre communication channel? The optical fibre channel is nonlinear, and the intensity-dependent Kerr nonlinearity limit has been suggested as a fundamental limit to optical fibre capacity. Current research is focused on whether this is the case, and on linear and nonlinear techniques, both optical and electronic, to understand, unlock and maximize the capacity of optical communications in the nonlinear regime. This paper describes some of them and discusses future prospects for success in the quest for capacity. PMID:26809572

  13. A Maximally Supersymmetric Kondo Model

    SciTech Connect

    Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo; /Stanford U., Phys. Dept. /SLAC

    2012-02-17

    We study the maximally supersymmetric Kondo model obtained by adding a fermionic impurity to N = 4 supersymmetric Yang-Mills theory. While the original Kondo problem describes a defect interacting with a free Fermi liquid of itinerant electrons, here the ambient theory is an interacting CFT, and this introduces qualitatively new features into the system. The model arises in string theory by considering the intersection of a stack of M D5-branes with a stack of N D3-branes, at a point in the D3 worldvolume. We analyze the theory holographically, and propose a dictionary between the Kondo problem and antisymmetric Wilson loops in N = 4 SYM. We perform an explicit calculation of the D5 fluctuations in the D3 geometry and determine the spectrum of defect operators. This establishes the stability of the Kondo fixed point together with its basic thermodynamic properties. Known supergravity solutions for Wilson loops allow us to go beyond the probe approximation: the D5s disappear and are replaced by three-form flux piercing a new topologically non-trivial S3 in the corrected geometry. This describes the Kondo model in terms of a geometric transition. A dual matrix model reflects the basic properties of the corrected gravity solution in its eigenvalue distribution.

  14. Maximal switchability of centralized networks

    NASA Astrophysics Data System (ADS)

    Vakulenko, Sergei; Morozov, Ivan; Radulescu, Ovidiu

    2016-08-01

    We consider continuous time Hopfield-like recurrent networks as dynamical models for gene regulation and neural networks. We are interested in networks that contain n high-degree nodes preferably connected to a large number of N s weakly connected satellites, a property that we call n/N s -centrality. If the hub dynamics is slow, we obtain that the large time network dynamics is completely defined by the hub dynamics. Moreover, such networks are maximally flexible and switchable, in the sense that they can switch from a globally attractive rest state to any structurally stable dynamics when the response time of a special controller hub is changed. In particular, we show that a decrease of the controller hub response time can lead to a sharp variation in the network attractor structure: we can obtain a set of new local attractors, whose number can increase exponentially with N, the total number of nodes of the nework. These new attractors can be periodic or even chaotic. We provide an algorithm, which allows us to design networks with the desired switching properties, or to learn them from time series, by adjusting the interactions between hubs and satellites. Such switchable networks could be used as models for context dependent adaptation in functional genetics or as models for cognitive functions in neuroscience.

  15. Heart failure

    PubMed Central

    2011-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of multidisciplinary interventions for heart failure? What are the effects of exercise in people with heart failure? What are the effects of drug treatments for heart failure? What are the effects of devices for treatment of heart failure? What are the effects of coronary revascularisation for treatment of heart failure? What are the effects of drug treatments in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 80 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium

  16. Maximal exercise as a countermeasure to orthostatic intolerance after spaceflight

    NASA Technical Reports Server (NTRS)

    Moore, A. D. Jr; Lee, S. M.; Charles, J. B.; Greenisen, M. C.; Schneider, S. M.

    2001-01-01

    Previous investigators have suggested that maximal exercise performed 24 h before the end of bed rest, a spaceflight analog, restores prebed rest plasma volume, baroreflex responses, and orthostatic tolerance. PURPOSE: In this case report, we examined the effect of a similar exercise protocol 24 h before a Shuttle landing on the orthostatic responses of four crewmembers (EX) after spaceflights of 8-14 d. Four additional crewmembers (CON) served as controls and did not perform exercise during the final day of the flight. METHODS: Each crewmember performed a 10-min stand test approximately 10 d before launch (L-10) and within 1-2 h of landing (R+0). Cardiac stroke volume was measured (Doppler ultrasound) supine and during each min of standing for three EX and three CON subjects. RESULTS: Preflight, all crewmembers completed the stand test and each group had similar heart rate and blood pressure responses. Postflight, all subjects also completed the 10-min stand test. Each group had similarly elevated supine and standing heart rates, elevated diastolic and mean arterial blood pressures, and reduced pulse pressures compared to L-10. However, postflight cardiac output, mean +/- SEM, (EX: 4.5+/-0.6 L x min(-1); CON: 3.1+/-0.3 L x min(-1)) and stroke volume (EX: 43+/-7 mL x beat; CON: 30+/-6 mL x beat) were higher after 10 min standing in the EX subjects compared to CON subjects. CONCLUSIONS: For these four crewmembers, maximal exercise performed 24 h before landing may have helped maintain stroke volume but did not maintain heart rate and blood pressure responses during standing compared to preflight.

  17. The relationship between cardiac autonomic function and maximal oxygen uptake response to high-intensity intermittent-exercise training.

    PubMed

    Boutcher, Stephen H; Park, Young; Dunn, Sarah Louise; Boutcher, Yati N

    2013-01-01

    Major individual differences in the maximal oxygen uptake response to aerobic training have been documented. Vagal influence on the heart has been shown to contribute to changes in aerobic fitness. Whether vagal influence on the heart also predicts maximal oxygen uptake response to interval-sprinting training, however, is undetermined. Thus, the relationship between baseline vagal activity and the maximal oxygen uptake response to interval-sprinting training was examined. Exercisers (n = 16) exercised three times a week for 12 weeks, whereas controls did no exercise (n = 16). Interval-sprinting consisted of 20 min of intermittent sprinting on a cycle ergometer (8 s sprint, 12 s recovery). Maximal oxygen uptake was assessed using open-circuit spirometry. Vagal influence was assessed through frequency analysis of heart rate variability. Participants were aged 22 ± 4.5 years and had a body mass of 72.7 ± 18.9 kg, a body mass index of 26.9 ± 3.9 kg · m(-2), and a maximal oxygen uptake of 28 ± 7.4 ml · kg(-1) · min(-1). Overall increase in maximal oxygen uptake after the training programme, despite being anaerobic in nature, was 19 ± 1.2%. Change in maximal oxygen uptake was correlated with initial baseline heart rate variability high-frequency power in normalised units (r = 0.58; P < 0.05). Thus, cardiac vagal modulation of heart rate was associated with the aerobic training response after 12 weeks of high-intensity intermittent-exercise. The mechanisms underlying the relationship between the aerobic training response and resting heart rate variability need to be established before practical implications can be identified.

  18. Heart failure

    PubMed Central

    2010-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of non-drug treatments, and of drug and invasive treatments, for heart failure? What are the effects of angiotensin-converting enzyme inhibitors in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 85 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium channel blockers, cardiac resynchronisation therapy, digoxin (in people already receiving diuretics and angiotensin-converting enzyme inhibitors), exercise, hydralazine plus isosorbide dinitrate, implantable cardiac

  19. Healthy Heart Quizzes

    MedlinePlus

    ... Cholesterol Tools & Resources Congenital Defects Children & Adults About Congenital Heart Defects The Impact of Congenital Heart Defects Understand Your Risk for Congenital Heart Defects Symptoms & ...

  20. Inflation in maximal gauged supergravities

    SciTech Connect

    Kodama, Hideo; Nozawa, Masato

    2015-05-18

    We discuss the dynamics of multiple scalar fields and the possibility of realistic inflation in the maximal gauged supergravity. In this paper, we address this problem in the framework of recently discovered 1-parameter deformation of SO(4,4) and SO(5,3) dyonic gaugings, for which the base point of the scalar manifold corresponds to an unstable de Sitter critical point. In the gauge-field frame where the embedding tensor takes the value in the sum of the 36 and 36’ representations of SL(8), we present a scheme that allows us to derive an analytic expression for the scalar potential. With the help of this formalism, we derive the full potential and gauge coupling functions in analytic forms for the SO(3)×SO(3)-invariant subsectors of SO(4,4) and SO(5,3) gaugings, and argue that there exist no new critical points in addition to those discovered so far. For the SO(4,4) gauging, we also study the behavior of 6-dimensional scalar fields in this sector near the Dall’Agata-Inverso de Sitter critical point at which the negative eigenvalue of the scalar mass square with the largest modulus goes to zero as the deformation parameter s approaches a critical value s{sub c}. We find that when the deformation parameter s is taken sufficiently close to the critical value, inflation lasts more than 60 e-folds even if the initial point of the inflaton allows an O(0.1) deviation in Planck units from the Dall’Agata-Inverso critical point. It turns out that the spectral index n{sub s} of the curvature perturbation at the time of the 60 e-folding number is always about 0.96 and within the 1σ range n{sub s}=0.9639±0.0047 obtained by Planck, irrespective of the value of the η parameter at the critical saddle point. The tensor-scalar ratio predicted by this model is around 10{sup −3} and is close to the value in the Starobinsky model.

  1. Mixed maximal and explosive strength training in recreational endurance runners.

    PubMed

    Taipale, Ritva S; Mikkola, Jussi; Salo, Tiina; Hokka, Laura; Vesterinen, Ville; Kraemer, William J; Nummela, Ari; Häkkinen, Keijo

    2014-03-01

    Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined during an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, n = 9), and control groups: men (MC, n = 7), women (WC, n = 9). The experimental groups performed mixed maximal and explosive exercises, whereas control subjects performed circuit training with body weight. Endurance training included running at an intensity below lactate threshold. Strength, power, endurance performance characteristics, and hormones were monitored throughout the study. Significance was set at p ≤ 0.05. Increases were observed in both experimental groups that were more systematic than in the control groups in explosive strength (12 and 13% in men and women, respectively), muscle activation, maximal strength (6 and 13%), and peak running speed (14.9 ± 1.2 to 15.6 ± 1.2 and 12.9 ± 0.9 to 13.5 ± 0.8 km Ł h). The control groups showed significant improvements in maximal and explosive strength, but Speak increased only in MC. Submaximal running characteristics (blood lactate and heart rate) improved in all groups. Serum hormones fluctuated significantly in men (testosterone) and in women (thyroid stimulating hormone) but returned to baseline by the end of the study. Mixed strength training combined with endurance training may be more effective than circuit training in recreational endurance runners to benefit overall fitness that may be important for other adaptive processes and larger training loads associated with, e.g., marathon training.

  2. Simple, heart-smart substitutions

    MedlinePlus

    Coronary artery disease - heart smart substitutions; Atherosclerosis - heart smart substitutions; Cholesterol - heart smart substitutions; Coronary heart disease - heart smart substitutions; Healthy diet - heart smart substitutions; Wellness - heart smart substitutions

  3. Women's Heart Disease: Heart Attack Symptoms

    MedlinePlus

    ... this page please turn JavaScript on. Feature: Women's Heart Disease Heart Attack Symptoms Past Issues / Winter 2014 Table ... NHLBI has uncovered some of the causes of heart diseases and conditions, as well as ways to prevent ...

  4. Heart Health: The Heart Truth Campaign 2009

    MedlinePlus

    ... Bar Home Current Issue Past Issues Cover Story Heart Health The Heart Truth Campaign 2009 Past Issues / Winter 2009 Table ... one of the celebrities supporting this year's The Heart Truth campaign. Both R&B singer Ashanti (center) ...

  5. Women's Heart Disease: Heart Disease Risk Factors

    MedlinePlus

    ... this page please turn JavaScript on. Feature: Women's Heart Disease Heart Disease Risk Factors Past Issues / Winter 2014 Table ... or habits may raise your risk for coronary heart disease (CHD). These conditions are known as risk ...

  6. Heart Health - Heart Disease: Symptoms, Diagnosis, Treatment

    MedlinePlus

    ... Bar Home Current Issue Past Issues Cover Story Heart Health Heart Disease: Symptoms, Diagnosis, Treatment Past Issues / Winter 2009 ... of this page please turn Javascript on. Most heart attacks happen when a clot in the coronary ...

  7. Heart Attack

    MedlinePlus

    ... to the heart.Usually, a blockage starts with atherosclerosis. Atherosclerosis is the buildup of fatty deposits (called plaque) ... Americans and native Hawaiians are at greater risk.Atherosclerosis (hardening of the arteries)Lack of exerciseStressObesitySex (Gender)-- ...

  8. Heart Truth

    MedlinePlus

    ... trademark of the U.S. Department of Health and Human Services and American Heart Association. Skip footer links and go to content Twitter Facebook YouTube Google+ SITE INDEX | ACCESSIBILITY | ... OIG | CONTACT US National Institutes of Health Department of Health and Human Services USA.gov

  9. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  10. Computing Maximally Supersymmetric Scattering Amplitudes

    NASA Astrophysics Data System (ADS)

    Stankowicz, James Michael, Jr.

    This dissertation reviews work in computing N = 4 super-Yang--Mills (sYM) and N = 8 maximally supersymmetric gravity (mSUGRA) scattering amplitudes in D = 4 spacetime dimensions in novel ways. After a brief introduction and overview in Ch. 1, the various techniques used to construct amplitudes in the remainder of the dissertation are discussed in Ch. 2. This includes several new concepts such as d log and pure integrand bases, as well as how to construct the amplitude using exactly one kinematic point where it vanishes. Also included in this chapter is an outline of the Mathematica package on shell diagrams and numerics.m (osdn) that was developed for the computations herein. The rest of the dissertation is devoted to explicit examples. In Ch. 3, the starting point is tree-level sYM amplitudes that have integral representations with residues that obey amplitude relations. These residues are shown to have corresponding residue numerators that allow a double copy prescription that results in mSUGRA residues. In Ch. 4, the two-loop four-point sYM amplitude is constructed in several ways, showcasing many of the techniques of Ch. 2; this includes an example of how to use osdn. The two-loop five-point amplitude is also presented in a pure integrand representation with comments on how it was constructed from one homogeneous cut of the amplitude. On-going work on the two-loop n-point amplitude is presented at the end of Ch. 4. In Ch. 5, the three-loop four-point amplitude is presented in the d log representation and in the pure integrand representation. In Ch. 6, there are several examples of four- through seven-loop planar diagrams that illustrate how considerations of the singularity structure of the amplitude underpin dual-conformal invariance. Taken with the previous examples, this is additional evidence that the structure known to exist in the planar sector extends to the full theory. At the end of this chapter is a proof that all mSUGRA amplitudes have a pole at

  11. Maximizing TDRS Command Load Lifetime

    NASA Technical Reports Server (NTRS)

    Brown, Aaron J.

    2002-01-01

    was therefore the key to achieving this goal. This goal was eventually realized through development of an Excel spreadsheet tool called EMMIE (Excel Mean Motion Interactive Estimation). EMMIE utilizes ground ephemeris nodal data to perform a least-squares fit to inferred mean anomaly as a function of time, thus generating an initial estimate for mean motion. This mean motion in turn drives a plot of estimated downtrack position difference versus time. The user can then manually iterate the mean motion, and determine an optimal value that will maximize command load lifetime. Once this optimal value is determined, the mean motion initially calculated by the command builder tool is overwritten with the new optimal value, and the command load is built for uplink to ISS. EMMIE also provides the capability for command load lifetime to be tracked through multiple TORS ephemeris updates. Using EMMIE, TORS command load lifetimes of approximately 30 days have been achieved.

  12. Specificity of a Maximal Step Exercise Test

    ERIC Educational Resources Information Center

    Darby, Lynn A.; Marsh, Jennifer L.; Shewokis, Patricia A.; Pohlman, Roberta L.

    2007-01-01

    To adhere to the principle of "exercise specificity" exercise testing should be completed using the same physical activity that is performed during exercise training. The present study was designed to assess whether aerobic step exercisers have a greater maximal oxygen consumption (max VO sub 2) when tested using an activity specific, maximal step…

  13. Heart disease and diet

    MedlinePlus

    Diet - heart disease; CAD - diet; Coronary artery disease - diet; Coronary heart disease - diet ... diet and lifestyle can reduce your risk of: Heart disease, heart attacks, and stroke Conditions that lead ...

  14. Coronary heart disease

    MedlinePlus

    Heart disease, Coronary heart disease, Coronary artery disease; Arteriosclerotic heart disease; CHD; CAD ... buildup of plaque in the arteries to your heart. This may also be called hardening of the ...

  15. What Is Heart Surgery?

    MedlinePlus

    ... Another type of heart surgery is called off-pump, or beating heart, surgery. It's like traditional open- ... heart-lung bypass machine isn't used. Off-pump heart surgery is limited to CABG. Surgeons can ...

  16. Anatomy of the Heart

    MedlinePlus

    ... picture of the outside of a normal, healthy, human heart. Heart Exterior Figure A shows the location of ... picture of the inside of a normal, healthy, human heart. Heart Interior Figure A shows the location of ...

  17. Diabetic Heart Disease

    MedlinePlus

    ... be coronary heart disease (CHD), heart failure, and diabetic cardiomyopathy. Diabetes by itself puts you at risk for heart disease. Other risk factors include Family history of heart disease Carrying extra ...

  18. Heart disease - resources

    MedlinePlus

    Resources - heart disease ... The following organizations are good resources for information on heart disease: American Heart Association -- www.heart.org Centers for Disease Control and Prevention -- www.cdc.gov/heartdisease

  19. Statistical mechanics of maximal independent sets

    NASA Astrophysics Data System (ADS)

    Dall'Asta, Luca; Pin, Paolo; Ramezanpour, Abolfazl

    2009-12-01

    The graph theoretic concept of maximal independent set arises in several practical problems in computer science as well as in game theory. A maximal independent set is defined by the set of occupied nodes that satisfy some packing and covering constraints. It is known that finding minimum and maximum-density maximal independent sets are hard optimization problems. In this paper, we use cavity method of statistical physics and Monte Carlo simulations to study the corresponding constraint satisfaction problem on random graphs. We obtain the entropy of maximal independent sets within the replica symmetric and one-step replica symmetry breaking frameworks, shedding light on the metric structure of the landscape of solutions and suggesting a class of possible algorithms. This is of particular relevance for the application to the study of strategic interactions in social and economic networks, where maximal independent sets correspond to pure Nash equilibria of a graphical game of public goods allocation.

  20. Impairment on cardiovascular and autonomic adjustments to maximal isometric exercise tests in offspring of hypertensive parents.

    PubMed

    Francica, Juliana V; Heeren, Marcelo V; Tubaldini, Márcio; Sartori, Michelle; Mostarda, Cristiano; Araujo, Rubens C; Irigoyen, Maria-Cláudia; De Angelis, Kátia

    2013-06-01

    The objective of the present study was to compare cardiovascular and autonomic responses to a mental stress test and to a maximal isometric exercise test between offspring of normotensive (ON, n = 10) and hypertensive parents (OH, n = 10). Subjects underwent a 3-min Stroop Color Word Test and a maximal isometric exercise test performed in an isokinetic dynamometer with continuous RR interval monitoring. At rest, arterial pressure and heart rate were similar between groups, but there was a significant reduction in total RR interval variance (ON: 5933 ± 493 vs. OH: 2967 ± 390 ms(2)) and an increase in low-high frequency components ratio of heart rate variability (ON: 2.3 ± 0.4 vs. OH: 4.6 ± 0.8) in OH group. In the first minute of the mental stress test and after both tests, the OH group presented increased heart rate as compared with the ON group. After both tests, only the ON group presented an increase in sympathetic component, thus reaching resting values similar to those of the OH group. Our data demonstrated increased resting cardiac sympathetic modulation in offspring of hypertensive parents at similar levels to that observed in offspring of normotensive parents after a mental stress test or a maximal isometric exercise test. Additionally, the exacerbated heart rate responses to these physiological tests in OH subjects may be associated with resting autonomic dysfunction, thus reinforcing these evaluations as important tools for detecting early dysfunctions in this genetically predisposed population.

  1. Pediatric heart surgery

    MedlinePlus

    Heart surgery - pediatric; Heart surgery for children; Acquired heart disease; Heart valve surgery - children ... There are many kinds of heart defects. Some are minor, and others are more serious. Defects can occur inside the heart or in the large blood vessels ...

  2. Heart Research

    NASA Technical Reports Server (NTRS)

    1991-01-01

    James Antaki and a group of researchers from the University of Pittsburgh School of Medicine used many elements of the Technology Utilization Program while looking for a way to visualize and track material points within the heart muscle. What they needed were tiny artificial "eggs" containing copper sulfate solution, small enough (about 2 mm in diameter) that they would not injure the heart, and large enough to be seen in Magnetic Resonance Imaging (MRI) images; they also had to be biocompatible and tough enough to withstand the beating of the muscle. The group could not make nor buy sufficient containers. After reading an article on microspheres in NASA Tech Briefs, and a complete set of reports on microencapsulation from the Jet Propulsion Laboratory (JPL), JPL put Antaki in touch with Dr.Taylor Wang of Vanderbilt University who helped construct the myocardial markers. The research is expected to lead to improved understanding of how the heart works and what takes place when it fails.

  3. A cycle ergometer test of maximal aerobic power.

    PubMed

    Myles, W S; Toft, R J

    1982-01-01

    An indirect test of maximal aerobic power (IMAP) was evaluated in 31 healthy male subjects by comparing it with a direct treadmill measurement of maximal aerobic power (VO2 max), with the prediction of VO2 max from heart rate during submaximal exercise on a cycle ergometer using Astrand's nomogram, with the British Army's Basic Fitness Test (BFT, a 2.4 km run performed in boots and trousers), and with a test of maximum anaerobic power. For the IMAP test, subjects pedalled on a cycle ergometer at 75 revs X min-1. The workload was 37.5 watts for the first minute, and was increased by 37.5 watts every minute until the subject could not continue. Time to exhaustion was recorded. Predicted VO2 max and times for BFT and IMAP correlated significantly (p less than 0.001) with the direct VO2 max: r = 0.70, r = 0.67 and r = 0.79 respectively. The correlation between direct VO2 max and the maximum anaerobic power test was significant (p less than 0.05) but lower, r = 0.44. Although lactate levels after direct VO2 max determination were significantly higher than those after the IMAP test, maximum heart rates were not significantly different. Submaximal VO2 values measured during the IMAP test yielded a regression equation relating VO2 and pedalling time. When individual values for direct and predicted VO2 max and times for BFT and IMAP were compared with equivalent standards, the percentages of subjects able to exceed the standard were 100, 65, 87, and 87 respectively. These data demonstrate that the IMAP test provides a valid estimate of VO2 max and indicate that it may be a practical test for establishing that an individual meets a minimum standard.

  4. Maximal Oxygen Consumption Is Reduced in Aquaporin-1 Knockout Mice

    PubMed Central

    Al-Samir, Samer; Goossens, Dominique; Cartron, Jean-Pierre; Nielsen, Søren; Scherbarth, Frank; Steinlechner, Stephan; Gros, Gerolf; Endeward, Volker

    2016-01-01

    We have measured maximal oxygen consumption (V˙O2,max) of mice lacking one or two of the established mouse red-cell CO2 channels AQP1, AQP9, and Rhag. We intended to study whether these proteins, by acting as channels for O2, determine O2 exchange in the lung and in the periphery. We found that V˙O2,max as determined by the Helox technique is reduced by ~16%, when AQP1 is knocked out, but not when AQP9 or Rhag are lacking. This figure holds for animals respiring normoxic as well as hypoxic gas mixtures. To see whether the reduction of V˙O2,max is due to impaired O2 uptake in the lung, we measured carotid arterial O2 saturation (SO2) by pulse oximetry. Neither under normoxic (inspiratory O2 21%) nor under hypoxic conditions (11% O2) is there a difference in SO2 between AQP1null and WT mice, suggesting that AQP1 is not critical for O2 uptake in the lung. The fact that the % reduction of V˙O2,max is identical in normoxia and hypoxia indicates moreover that the limitation of V˙O2,max is not due to an O2 diffusion problem, neither in the lung nor in the periphery. Instead, it appears likely that AQP1null animals exhibit a reduced V˙O2,max due to the reduced wall thickness and muscle mass of the left ventricles of their hearts, as reported previously. We conclude that very likely the properties of the hearts of AQP1 knockout mice cause a reduced maximal cardiac output and thus cause a reduced V˙O2,max, which constitutes a new phenotype of these mice. PMID:27559317

  5. [Therapy of terminal heart failure using heart transplantation].

    PubMed

    Hummel, M; Warnecke, H; Schüler, S; Hempel, B; Spiegelsberger, S; Hetzer, R

    1991-08-16

    Heart transplantation (HTx) has now become an accepted treatment modality for end-stage heart disease. The limited supply of suitable donor organs imposes constraints upon the decision of who should be selected for transplantation. Usually patients are candidates for HTx, who remain NYHA functional class III or IV despite maximal medical therapy. Further criteria are low left ventricular ejection fraction (less than 20%) with heart rhythm disturbances class IIIA-V (LOWN), which are associated with poor prognosis. Additionally, the suffering of the patient and also the course of heart failure are essential for judging the urgency of HTx. Contraindications are absolute in patients with untreated infections, fixed pulmonary vascular resistance (PVR) above 8 WOOD-degrees, severe irreversible kidney and liver disease, active ventricular or duodenal ulcers and acute, psychiatric illness. HTx is relatively contraindicated in patients with diabetes mellitus, age over 60 years, PVR above 6 WOOD-degrees and an unstable psychosocial situation. To prevent rejection of the transplant heart, live-long immunosuppressive therapy is needed. Most immunosuppressive regimes consist of Cyclosporine A and Azathioprine (double drug therapy) or in combination (tripple drug therapy) with Prednisolone. For monitoring of this therapy, control of hole blood cyclosporine A level and white blood count is needed. Rejection episodes can be suspected if there is a greater than 20 mmHg decrease of systolic blood pressure, elevated body temperature, malaise, tachycardia or heart rhythm disturbance. The diagnosis of cardiac rejection can be established by endomyocardial biopsy. Measurement of the voltage of either the surface or intramyocardial ECG, echocardiography with special consideration to early left ventricular filling time as well as immunological methods are additionally used tools. Graft sclerosis as the main risk factor of the late transplant period remains an unsolved problem.

  6. Neuromagnetic imaging of movement-related cortical oscillations in children and adults: age predicts post-movement beta rebound.

    PubMed

    Gaetz, W; Macdonald, M; Cheyne, D; Snead, O C

    2010-06-01

    We measured visually-cued motor responses in two developmentally separate groups of children and compared these responses to a group of adults. We hypothesized that if post-movement beta rebound (PMBR) depends on developmentally sensitive processes, PMBR will be greatest in adults and progressively decrease in children performing a basic motor task as a function of age. Twenty children (10 young children 4-6 years; 10 adolescent children 11-13 years) and 10 adults all had MEG recorded during separate recordings of right and left index finger movements. Beta band (15-30 Hz) event-related desynchronization (ERD) of bi-lateral sensorimotor areas was observed to increase significantly from both contralateral and ipsilateral MI with age. Movement-related gamma synchrony (60-90 Hz) was also observed from contralateral MI for each age group. However, PMBR was significantly reduced in the 4-6 year group and, while more prominent, remained significantly diminished in the adolescent (11-13 year) age group as compared to adults. PMBR measures were weak or absent in the youngest children tested and appear maximally from bilateral MI in adults. Thus PMBR may reflect an age-dependent inhibitory process of the primary motor cortex which comes on-line with normal development. Previous studies have shown PMBR may be observed from MI following a variety of movement-related tasks in adult participants - however, the origin and purpose of the PMBR is unclear. The current study shows that the expected PMBR from MI observed from adults is increasingly diminished in adolescent and young children respectively. A reduction in PMBR from children may reflect reduced motor cortical inhibition. Relatively less motor inhibition may facilitate neuronal plasticity and promote motor learning in children.

  7. Heart rate responses of women aged 23–67 years during competitive orienteering

    PubMed Central

    Bird, S; George, M; Balmer, J; Davison, R

    2003-01-01

    Objectives: To compare the heart rate responses of women orienteers of different standards and to assess any relation between heart rate responses and age. Methods: Eighteen competitive women orienteers completed the study. They were divided into two groups: eight national standard orienteers (ages 23–67 years); 10 club standard orienteers (ages 24–67 years). Each participant had her heart rate monitored during a race recognised by the British Orienteering Federation. Peak heart rate (HRPEAK), mean heart rate (HRMEAN), standard deviation of her heart rate during each orienteering race (HRSD), and mean change in heart rate at each control point (ΔHRCONTROL) were identified. The data were analysed using analysis of covariance with age as a covariate. Results: National standard orienteers displayed a lower within orienteering race standard deviation in heart rate (6 (2) v 12 (2) beats/min, p<0.001) and a lower ΔHRCONTROL (5 (1) v 17 (4) beats/min, p<0.001). The mean heart rate during competition was higher in the national standard group (170 (11) v 158 (11) beats/min, p = 0.025). The HRMEAN for the national and club standard groups were 99 (8)% and 88 (9)% of their age predicted maximum heart rate (220-age) respectively. All orienteers aged >55 years (n = 4) recorded HRMEAN greater than their age predicted maximum. Conclusions: The heart rate responses indicate that national and club standard women orienteers of all ages participate in the sport at a vigorous intensity. The higher ΔHRCONTROL of club standard orienteers is probably due to failing to plan ahead before arriving at the controls and this, coupled with slowing down to navigate or relocate when lost, produced a higher HRSD. PMID:12782552

  8. Comparison of maximal oxygen consumption with oral and nasal breathing.

    PubMed

    Morton, A R; King, K; Papalia, S; Goodman, C; Turley, K R; Wilmore, J H

    1995-09-01

    The major cause of exercise-induced asthma (EIA) is thought to be the drying and cooling of the airways during the 'conditioning' of the inspired air. Nasal breathing increases the respiratory system's ability to warm and humidity the inspired air compared to oral breathing and reduces the drying and cooling effects of the increased ventilation during exercise. This will reduce the severity of EIA provoked by a given intensity and duration of exercise. The purpose of the study was to determine the exercise intensity (%VO2 max) at which healthy subjects, free from respiratory disease, could perform while breathing through the nose-only and to compare this with mouth-only and mouth plus nose breathing. Twenty subjects (11 males and 9 females) ranging from 18-55 years acted as subjects in this study. They were all non-smokers and non-asthmatic. At the time of the study, all subjects were involved in regular physical activity and were classified, by a physician, as free from nasal polyps or other nasal obstruction. The percentage decrease in maximal ventilation with nose-only breathing compare to mouth and mouth plus nose breathing was three times the percentage decrease in maximal oxygen consumption. The pattern of nose-only breathing at maximal work showed a small reduction in tidal volume and large reduction in breathing frequency. Nasal breathing resulted in a reduction in FEO2 and an increase in FECO2. While breathing through the nose-only, all subjects could attain a work intensity great enough to produce an aerobic training effect (based on heart rate and percentage of VO2 max).

  9. Congenital Heart Defects (For Parents)

    MedlinePlus

    ... heart, lungs, and blood vessels make up the circulatory system . The heart is the central pump of this ... Heart Defects Getting an EKG (Video) Your Heart & Circulatory System Heart Murmurs Mitral Valve Prolapse Movie: Heart & Circulatory ...

  10. ISL1 Is Necessary for Maximal Thyrotrope Response to Hypothyroidism

    PubMed Central

    Castinetti, F.; Brinkmeier, M. L.; Mortensen, A. H.; Vella, K. R.; Gergics, P.; Brue, T.; Hollenberg, A. N.; Gan, L.

    2015-01-01

    ISLET1 is a homeodomain transcription factor necessary for development of the pituitary, retina, motor neurons, heart, and pancreas. Isl1-deficient mice (Isl1−/−) die early during embryogenesis at embryonic day 10.5 due to heart defects, and at that time, they have an undersized pituitary primordium. ISL1 is expressed in differentiating pituitary cells in early embryogenesis. Here, we report the cell-specific expression of ISL1 and assessment of its role in gonadotropes and thyrotropes. Isl1 expression is elevated in pituitaries of Cga−/− mice, a model of hypothyroidism with thyrotrope hypertrophy and hyperplasia. Thyrotrope-specific disruption of Isl1 with Tshb-cre is permissive for normal serum TSH, but T4 levels are decreased, suggesting decreased thyrotrope function. Inducing hypothyroidism in normal mice causes a reduction in T4 levels and dramatically elevated TSH response, but mice with thyrotrope-specific disruption of Isl1 have a blunted TSH response. In contrast, deletion of Isl1 in gonadotropes with an Lhb-cre transgene has no obvious effect on gonadotrope function or fertility. These results show that ISL1 is necessary for maximal thyrotrope response to hypothyroidism, in addition to its role in development of Rathke's pouch. PMID:26296153

  11. Effects of biofeedback training on voluntary heart rate control during dynamic exercise.

    PubMed

    Alvarez Moleiro, M; Villamaín Cid, F

    2001-12-01

    The aims of this study were to (1) compare the effect of biofeedback with that of verbal instructions on the control of heart rate during exercise on a treadmill, (2) test the possible effect of workload on this control, and (3) examine the effect of workload on baseline heart rate at rest and during exercise. The study involved 35 participants who were randomly assigned to each of 4 experimental conditions generated by combining the 2 independent variables: training strategy for heart rate control (heart rate biofeedback or verbal control instructions) and work level (30 or 50% of maximal heart rate). By the end of 5 experimental sessions, participants trained with heart rate biofeedback showed a greater attenuation of the increase in heart rate produced by exercise than participants trained with verbal control instructions. The workload did not influence the voluntary control of heart rate, nor did it affect resting baseline heart rate, but it did affect exercise baseline heart rate.

  12. Heart rate response to hypoxic exercise: role of dopamine D2-receptors and effect of oxygen supplementation.

    PubMed

    Lundby, C; Møller, P; Kanstrup, I L; Olsen, N V

    2001-10-01

    This study examined the effects of dopamine D(2)-receptor blockade on the early decrease in maximal heart rate at high altitude (4559 m). We also attempted to clarify the time-dependent component of this reduction and the extent to which it is reversed by oxygen breathing. Twelve subjects performed two consecutive maximal exercise tests, without and with oxygen supplementation respectively, at sea level and after 1, 3 and 5 days at altitude. On each study day, domperidone (30 mg; n=6) or no medication (n=6) was given 1 h before the first exercise session. Compared with sea level, hypoxia progressively decreased the maximal heart rate from day 1 and onwards; also, hypoxia by itself increased plasma noradrenaline levels after maximal exercise. Domperidone further increased maximal noradrenaline concentrations, but had no effect on maximal heart rate. On each study day at altitude, oxygen breathing completely reversed the decrease in maximal heart rate to values not different from those at sea level. In conclusion, dopamine D(2)-receptor blockade with domperidone demonstrates that hypoxic exercise in humans activates D(2)-receptors, resulting in a decrease in circulating levels of noradrenaline. However, dopamine D(2)-receptors are not involved in the hypoxia-induced decrease in the maximal heart rate. These data suggest that receptor uncoupling, and not down-regulation, of cardiac adrenoreceptors, is responsible for the early decrease in heart rate at maximal hypoxic exercise.

  13. Maximizing Complementary Quantities by Projective Measurements

    NASA Astrophysics Data System (ADS)

    M. Souza, Leonardo A.; Bernardes, Nadja K.; Rossi, Romeu

    2017-04-01

    In this work, we study the so-called quantitative complementarity quantities. We focus in the following physical situation: two qubits ( q A and q B ) are initially in a maximally entangled state. One of them ( q B ) interacts with a N-qubit system ( R). After the interaction, projective measurements are performed on each of the qubits of R, in a basis that is chosen after independent optimization procedures: maximization of the visibility, the concurrence, and the predictability. For a specific maximization procedure, we study in detail how each of the complementary quantities behave, conditioned on the intensity of the coupling between q B and the N qubits. We show that, if the coupling is sufficiently "strong," independent of the maximization procedure, the concurrence tends to decay quickly. Interestingly enough, the behavior of the concurrence in this model is similar to the entanglement dynamics of a two qubit system subjected to a thermal reservoir, despite that we consider finite N. However, the visibility shows a different behavior: its maximization is more efficient for stronger coupling constants. Moreover, we investigate how the distinguishability, or the information stored in different parts of the system, is distributed for different couplings.

  14. Right heart ventriculography

    MedlinePlus

    Angiography - right heart ... moved forward into the right side of the heart. As the catheter is advanced, the doctor can ... is injected into the right side of the heart. It helps the cardiologist determine the size and ...

  15. Left heart catheterization

    MedlinePlus

    Catheterization - left heart ... to help guide the catheters up into your heart and arteries. Dye (sometimes called "contrast") will be ... in the blood vessels that lead to your heart. The catheter is then moved through the aortic ...

  16. Heart disease and women

    MedlinePlus

    ... disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, ... the American Heart Association and American College of Cardiology Foundation endorsed by the World Heart Federation and ...

  17. Honolulu Heart Program

    ClinicalTrials.gov

    2016-04-13

    Cardiovascular Diseases; Coronary Disease; Cerebrovascular Accident; Heart Diseases; Heart Failure, Congestive; Myocardial Infarction; Asthma; Emphysema; Lung Diseases, Obstructive; Aortic Aneurysm, Abdominal; Bronchitis; Dementia; Hypertension; Chronic Obstructive Pulmonary Disease; Heart Failure

  18. Heart Attack Recovery FAQs

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Heart Attack Recovery FAQs Updated:Sep 19,2016 Most people ... recovery. View an animation of a heart attack . Heart Attack Recovery Questions and Answers What treatments will I ...

  19. Heart Surgery Terms

    MedlinePlus

    ... the hearts of humans who have died (cadavers). Angina pectoris The discomfort experienced by individuals when their heart ... performed during symptoms suggestive of coronary artery disease angina pectoris , abnormalities may confirm the diagnosis of ischemic heart ...

  20. Heart disease and depression

    MedlinePlus

    ... gov/ency/patientinstructions/000790.htm Heart disease and depression To use the sharing features on this page, ... a heart attack or heart surgery Signs of Depression It is pretty common to feel down or ...

  1. Getting a New Heart

    MedlinePlus

    ... About Heart Transplants American Society of Transplantation 1120 Route 73, Suite 200 Mount Laurel, NJ 08054 Phone: ... of heart disease; these patients have no other choice. The best treatment for your heart failure will ...

  2. Lipidome determinants of maximal lifespan in mammals.

    PubMed

    Bozek, Katarzyna; Khrameeva, Ekaterina E; Reznick, Jane; Omerbašić, Damir; Bennett, Nigel C; Lewin, Gary R; Azpurua, Jorge; Gorbunova, Vera; Seluanov, Andrei; Regnard, Pierrick; Wanert, Fanelie; Marchal, Julia; Pifferi, Fabien; Aujard, Fabienne; Liu, Zhen; Shi, Peng; Pääbo, Svante; Schroeder, Florian; Willmitzer, Lothar; Giavalisco, Patrick; Khaitovich, Philipp

    2017-12-01

    Maximal lifespan of mammalian species, even if closely related, may differ more than 10-fold, however the nature of the mechanisms that determine this variability is unresolved. Here, we assess the relationship between maximal lifespan duration and concentrations of more than 20,000 lipid compounds, measured in 669 tissue samples from 6 tissues of 35 species representing three mammalian clades: primates, rodents and bats. We identify lipids associated with species' longevity across the three clades, uncoupled from other parameters, such as basal metabolic rate, body size, or body temperature. These lipids clustered in specific lipid classes and pathways, and enzymes linked to them display signatures of greater stabilizing selection in long-living species, and cluster in functional groups related to signaling and protein-modification processes. These findings point towards the existence of defined molecular mechanisms underlying variation in maximal lifespan among mammals.

  3. An information maximization model of eye movements

    NASA Technical Reports Server (NTRS)

    Renninger, Laura Walker; Coughlan, James; Verghese, Preeti; Malik, Jitendra

    2005-01-01

    We propose a sequential information maximization model as a general strategy for programming eye movements. The model reconstructs high-resolution visual information from a sequence of fixations, taking into account the fall-off in resolution from the fovea to the periphery. From this framework we get a simple rule for predicting fixation sequences: after each fixation, fixate next at the location that minimizes uncertainty (maximizes information) about the stimulus. By comparing our model performance to human eye movement data and to predictions from a saliency and random model, we demonstrate that our model is best at predicting fixation locations. Modeling additional biological constraints will improve the prediction of fixation sequences. Our results suggest that information maximization is a useful principle for programming eye movements.

  4. Singularity structure of maximally supersymmetric scattering amplitudes.

    PubMed

    Arkani-Hamed, Nima; Bourjaily, Jacob L; Cachazo, Freddy; Trnka, Jaroslav

    2014-12-31

    We present evidence that loop amplitudes in maximally supersymmetric (N=4) Yang-Mills theory (SYM) beyond the planar limit share some of the remarkable structures of the planar theory. In particular, we show that through two loops, the four-particle amplitude in full N=4 SYM has only logarithmic singularities and is free of any poles at infinity--properties closely related to uniform transcendentality and the UV finiteness of the theory. We also briefly comment on implications for maximal (N=8) supergravity theory (SUGRA).

  5. Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

    PubMed

    Mellis, M G; Ingle, L; Carroll, S

    2014-02-01

    This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P < 0.001). Lower coefficient of variation (≤ 10.2%) and narrower limits of agreement were found for actual heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults.

  6. Heart failure - medicines

    MedlinePlus

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  7. Understanding violations of Gricean maxims in preschoolers and adults

    PubMed Central

    Okanda, Mako; Asada, Kosuke; Moriguchi, Yusuke; Itakura, Shoji

    2015-01-01

    This study used a revised Conversational Violations Test to examine Gricean maxim violations in 4- to 6-year-old Japanese children and adults. Participants' understanding of the following maxims was assessed: be informative (first maxim of quantity), avoid redundancy (second maxim of quantity), be truthful (maxim of quality), be relevant (maxim of relation), avoid ambiguity (second maxim of manner), and be polite (maxim of politeness). Sensitivity to violations of Gricean maxims increased with age: 4-year-olds' understanding of maxims was near chance, 5-year-olds understood some maxims (first maxim of quantity and maxims of quality, relation, and manner), and 6-year-olds and adults understood all maxims. Preschoolers acquired the maxim of relation first and had the greatest difficulty understanding the second maxim of quantity. Children and adults differed in their comprehension of the maxim of politeness. The development of the pragmatic understanding of Gricean maxims and implications for the construction of developmental tasks from early childhood to adulthood are discussed. PMID:26191018

  8. How to Generate Good Profit Maximization Problems

    ERIC Educational Resources Information Center

    Davis, Lewis

    2014-01-01

    In this article, the author considers the merits of two classes of profit maximization problems: those involving perfectly competitive firms with quadratic and cubic cost functions. While relatively easy to develop and solve, problems based on quadratic cost functions are too simple to address a number of important issues, such as the use of…

  9. Robust Utility Maximization Under Convex Portfolio Constraints

    SciTech Connect

    Matoussi, Anis; Mezghani, Hanen Mnif, Mohamed

    2015-04-15

    We study a robust maximization problem from terminal wealth and consumption under a convex constraints on the portfolio. We state the existence and the uniqueness of the consumption–investment strategy by studying the associated quadratic backward stochastic differential equation. We characterize the optimal control by using the duality method and deriving a dynamic maximum principle.

  10. Maximizing the Spectacle of Water Fountains

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    For a given initial speed of water from a spigot or jet, what angle of the jet will maximize the visual impact of the water spray in the fountain? This paper focuses on fountains whose spigots are arranged in circular fashion, and couches the measurement of the visual impact in terms of the surface area and the volume under the fountain's natural…

  11. Maximizing the Effective Use of Formative Assessments

    ERIC Educational Resources Information Center

    Riddell, Nancy B.

    2016-01-01

    In the current age of accountability, teachers must be able to produce tangible evidence of students' concept mastery. This article focuses on implementation of formative assessments before, during, and after instruction in order to maximize teachers' ability to effectively monitor student achievement. Suggested strategies are included to help…

  12. Maximal dinucleotide comma-free codes.

    PubMed

    Fimmel, Elena; Strüngmann, Lutz

    2016-01-21

    The problem of retrieval and maintenance of the correct reading frame plays a significant role in RNA transcription. Circular codes, and especially comma-free codes, can help to understand the underlying mechanisms of error-detection in this process. In recent years much attention has been paid to the investigation of trinucleotide circular codes (see, for instance, Fimmel et al., 2014; Fimmel and Strüngmann, 2015a; Michel and Pirillo, 2012; Michel et al., 2012, 2008), while dinucleotide codes had been touched on only marginally, even though dinucleotides are associated to important biological functions. Recently, all maximal dinucleotide circular codes were classified (Fimmel et al., 2015; Michel and Pirillo, 2013). The present paper studies maximal dinucleotide comma-free codes and their close connection to maximal dinucleotide circular codes. We give a construction principle for such codes and provide a graphical representation that allows them to be visualized geometrically. Moreover, we compare the results for dinucleotide codes with the corresponding situation for trinucleotide maximal self-complementary C(3)-codes. Finally, the results obtained are discussed with respect to Crick׳s hypothesis about frame-shift-detecting codes without commas.

  13. DNA solution of the maximal clique problem.

    PubMed

    Ouyang, Q; Kaplan, P D; Liu, S; Libchaber, A

    1997-10-17

    The maximal clique problem has been solved by means of molecular biology techniques. A pool of DNA molecules corresponding to the total ensemble of six-vertex cliques was built, followed by a series of selection processes. The algorithm is highly parallel and has satisfactory fidelity. This work represents further evidence for the ability of DNA computing to solve NP-complete search problems.

  14. Maximizing Resource Utilization in Video Streaming Systems

    ERIC Educational Resources Information Center

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  15. Ehrenfest's Lottery--Time and Entropy Maximization

    ERIC Educational Resources Information Center

    Ashbaugh, Henry S.

    2010-01-01

    Successful teaching of the Second Law of Thermodynamics suffers from limited simple examples linking equilibrium to entropy maximization. I describe a thought experiment connecting entropy to a lottery that mixes marbles amongst a collection of urns. This mixing obeys diffusion-like dynamics. Equilibrium is achieved when the marble distribution is…

  16. Why Contextual Preference Reversals Maximize Expected Value

    PubMed Central

    2016-01-01

    Contextual preference reversals occur when a preference for one option over another is reversed by the addition of further options. It has been argued that the occurrence of preference reversals in human behavior shows that people violate the axioms of rational choice and that people are not, therefore, expected value maximizers. In contrast, we demonstrate that if a person is only able to make noisy calculations of expected value and noisy observations of the ordinal relations among option features, then the expected value maximizing choice is influenced by the addition of new options and does give rise to apparent preference reversals. We explore the implications of expected value maximizing choice, conditioned on noisy observations, for a range of contextual preference reversal types—including attraction, compromise, similarity, and phantom effects. These preference reversal types have played a key role in the development of models of human choice. We conclude that experiments demonstrating contextual preference reversals are not evidence for irrationality. They are, however, a consequence of expected value maximization given noisy observations. PMID:27337391

  17. Maximizing the Motivated Mind for Emergent Giftedness.

    ERIC Educational Resources Information Center

    Rea, Dan

    2001-01-01

    This article explains how the theory of the motivated mind conceptualizes the productive interaction of intelligence, creativity, and achievement motivation and how this theory can help educators to maximize students' emergent potential for giftedness. It discusses the integration of cold-order thinking and hot-chaotic thinking into fluid-adaptive…

  18. A Model of College Tuition Maximization

    ERIC Educational Resources Information Center

    Bosshardt, Donald I.; Lichtenstein, Larry; Zaporowski, Mark P.

    2009-01-01

    This paper develops a series of models for optimal tuition pricing for private colleges and universities. The university is assumed to be a profit maximizing, price discriminating monopolist. The enrollment decision of student's is stochastic in nature. The university offers an effective tuition rate, comprised of stipulated tuition less financial…

  19. Formation Control for the Maxim Mission.

    NASA Technical Reports Server (NTRS)

    Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

    2004-01-01

    Over the next twenty years, a wave of change is occurring in the spacebased scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today's technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. The Stellar Imager mission requirements are on the same order of those for MAXIM. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; (2) the formation control architecture devised for such missions; (3) the design of the formation control laws to maintain very high precision relative positions; and (4) the levels of fuel usage required in the duration of these missions. Specific preliminary results are presented for two spacecraft within the MAXIM mission.

  20. Heart failure.

    PubMed

    Braunwald, Eugene

    2013-02-01

    Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.

  1. Hypoplastic left heart syndrome (image)

    MedlinePlus

    Hypoplastic left heart syndrome is a congenital heart condition that occurs during the development of the heart in the ... womb. During the heart's development, parts of the left side of the heart (mitral valve, left ventricle ...

  2. In-Game Heart Rate Responses Among Professional Baseball Starting Pitchers.

    PubMed

    Cornell, David J; Paxson, Jeffrey L; Caplinger, Roger A; Seligman, Joshua R; Davis, Nicholas A; Flees, Robert J; Ebersole, Kyle T

    2017-01-01

    Cornell, DJ, Paxson, JL, Caplinger, RA, Seligman, JR, Davis, NA, Flees, RJ, and Ebersole, KT. In-game heart rate responses among professional baseball starting pitchers. J Strength Cond Res 31(1): 24-29, 2017-The purpose of the current study was to characterize the in-game heart rate (HR) responses of baseball pitching. In-game HR was recorded from 16 professional baseball starting pitchers (mean ± SD, age = 22.1 ± 1.3 years; height = 187.9 ± 4.4 cm; weight = 90.5 ± 9.5 kg) for a total of 682 innings (home = 381, away = 301). All analyzed HR data were then normalized to each pitcher's age-predicted maximal HR (%HRmax). The group mean ± SD in-game %HRmax among all pitchers was 84.8 ± 3.9%, suggesting that baseball pitching is predominantly an anaerobic task. A split-plot mixed-model repeated measures analysis of variance identified a significant interaction effect between inning and game location (p = 0.042). Follow-up simple effects indicated that the in-game %HRmax was significantly different across innings, but only during home starts (p < 0.001). Specifically, pairwise analyses indicated that the in-game %HRmax during home starts were significantly (p ≤ 0.05) higher in the first and second innings than in all other innings. In addition, follow-up simple effects indicated that the in-game %HRmax was significantly (p = 0.017) higher during home starts than away starts in the first inning (87.3 ± 3.6% vs. 85.8 vs. 3.8%, respectively). Thus, it is possible that inning-dependent psychological factors may have contributed to the observed changes in in-game physiological intensity across innings and that these factors are specific to game location. Consequently, strength and conditioning practitioners should prescribe high-intensity exercises when developing conditioning programs for professional baseball starting pitchers.

  3. Role of the Frank-Starling mechanism during maximal semisupine exercise after oral atenolol.

    PubMed

    Andersen, K; Vik-Mo, H

    1982-08-01

    Reproducible left ventricular dimensions were found by M-mode echocardiography in eight healthy men in the semisupine position during two maximal bicycle exercise tests, performed with four hours interval. Left ventricular end-diastolic dimension did not increase during maximal exercise, while fractional shortening increased by a decrease in end-systolic dimension. Twelve men studied by the same procedure were given 100 mg atenolol orally just after the first test which conspicuously reduced their heart rate response to exercise. End-diastolic dimension increased significantly from rest to peak exercise after the administration of atenolol in contrast to that before beta blockade, and fractional shortening at maximal exercise increased compared with the preceding control test. We conclude that atenolol changes the left ventricular response to maximal semisupine exercise in normal man, with dilatation and a concomitant increase in systolic myocardial shortening. This suggests that atenolol during maximal exercise reveals the part played by the Frank-Starling mechanism in cardiac reserve. In addition to that mechanism, the increased ventricular emptying is probably also the result of reduced afterload after administration of atenolol.

  4. Role of the Frank-Starling mechanism during maximal semisupine exercise after oral atenolol.

    PubMed Central

    Andersen, K; Vik-Mo, H

    1982-01-01

    Reproducible left ventricular dimensions were found by M-mode echocardiography in eight healthy men in the semisupine position during two maximal bicycle exercise tests, performed with four hours interval. Left ventricular end-diastolic dimension did not increase during maximal exercise, while fractional shortening increased by a decrease in end-systolic dimension. Twelve men studied by the same procedure were given 100 mg atenolol orally just after the first test which conspicuously reduced their heart rate response to exercise. End-diastolic dimension increased significantly from rest to peak exercise after the administration of atenolol in contrast to that before beta blockade, and fractional shortening at maximal exercise increased compared with the preceding control test. We conclude that atenolol changes the left ventricular response to maximal semisupine exercise in normal man, with dilatation and a concomitant increase in systolic myocardial shortening. This suggests that atenolol during maximal exercise reveals the part played by the Frank-Starling mechanism in cardiac reserve. In addition to that mechanism, the increased ventricular emptying is probably also the result of reduced afterload after administration of atenolol. Images PMID:7093084

  5. Running speed and maximal oxygen uptake in rats and mice: practical implications for exercise training.

    PubMed

    Høydal, Morten A; Wisløff, Ulrik; Kemi, Ole J; Ellingsen, Oyvind

    2007-12-01

    Valid and reliable experimental models are essential to gain insight into the cellular and molecular mechanisms underlying the beneficial effects of exercise in prevention, treatment, and rehabilitation of lifestyle-related diseases. Studies with large changes, low variation, and reproducible training outcome require individualized training intensity, controlled by direct measurements of maximal oxygen uptake or heart rate. As this approach is expensive and time consuming, we discuss whether maximal treadmill running speed in a gradually increasing ramp protocol might be sufficient to control intensity without losing accuracy. Combined data from six studies of rats and mice from our lab demonstrated a close correlation between running speed and oxygen uptake. This relationship changed towards a steeper linear slope after endurance training, indicating improved work economy, that is, less oxygen was consumed at fixed submaximal running speeds. Maximal oxygen uptake increased 40-70% after high-intensity aerobic interval training in mice and rats. The speed at which oxygen uptake reached a plateau, increased in parallel with the change in maximal oxygen uptake during the training period. Although this suggests that running speed can be used to assess training intensity throughout a training program, the problem is to determine the exact relative intensity related to maximal oxygen uptake from running speed alone. We therefore suggest that directly measured oxygen uptake should be used to assess exercise intensity and optimize endurance training in rats and mice. Running speed may serve as a supplement to ensure this intensity.

  6. Pediatric heart surgery - discharge

    MedlinePlus

    ... get enough calories to heal and grow. After heart surgery, most babies and infants (younger than 12 to 15 months) can take ... valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... open heart surgery References Bernstein D. General principles ...

  7. Advanced Heart Failure

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Advanced Heart Failure Updated:Feb 9,2017 When heart failure (HF) ... content was last reviewed on 04/06/2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  8. High-Intensity Inspiratory Protocol Increases Heart Rate Variability in Myocardial Revascularization Patients

    PubMed Central

    Caruso, Flavia Cristina Rossi; Simões, Rodrigo Polaquini; Reis, Michel Silva; Guizilini, Solange; Alves, Vera Lucia dos Santos; Papa, Valeria; Arena, Ross; Borghi-Silva, Audrey

    2016-01-01

    Objective: To evaluate heart rate variability during an inspiratory muscle endurance protocol at three different load levels [30%, 60% and 80% of maximal inspiratory pressure], in patients who had previously undergone coronary artery bypass grafting. Methods: Nineteen late postoperative myocardial revascularization patients participating in a cardiovascular rehabilitation program were studied. Maximal inspiratory pressure maneuvers were performed. An inspiratory muscle endurance protocol at 30%, 60% and 80% of maximal inspiratory pressure was applied for four minutes each, in random order. Heart rate and RR intervals were recorded and heart rate variability was analyzed by time (RMSSD-the mean of the standard deviations for all R-R intervals, and RMSM-root-mean square differences of successive R-R intervals) and frequency domains indices (high and low frequency) in normalized units. ANOVA for repeated measurements was used to compare heart rate variability indices and Student t-test was used to compare the maximal inspiratory pressure and maximal expiratory pressure values. Results: Heart rate increased during performance of maximal respiratory pressures maneuvers, and the maximal inspiratory pressure and maximal expiratory pressure mean values were significantly lower than predicted values (P<0.05). RMSSD increased significantly at 80% in relation to rest and 30% of maximal inspiratory pressure and RMSM decreased at 30% and 60% of maximal inspiratory pressure in relation to rest (P<0.05). Additionally, there was significant and progressive decrease in low frequency and increase in high frequency at 30%, 60% and 80% of maximal inspiratory pressure in relation to the resting condition. Conclusion: These results suggest that respiratory muscle training at high intensities can promote greater parasympathetic activity and it may confer important benefits during a rehabilitation program in post-coronary artery bypass grafting. PMID:27074273

  9. Congenital complete heart block.

    PubMed Central

    Agarwala, B.; Sheikh, Z.; Cibils, L. A.

    1996-01-01

    Congenital complete heart block in utero has become diagnosed more frequently with the clinical use of fetal echocardiography. The fetus with complete heart block may remain asymptomatic or may develop congestive heart failure. Congenital complete heart block is more frequently seen in infants of mothers with systemic lupus erythematosus, both clinically manifested and subclinical systemic lupus erythematosus with positive antibodies (SS-A and SS-B antibodies). At birth, the neonate with complete heart block may remain asymptomatic and may not require a pacemaker to increase the heart rate. The indications for a pacemaker in neonates with complete heart block have been discussed. Both in-utero and neonatal management of congenital complete heart block are discussed to manage congestive heart failure in a fetus. Four patients with congenital complete heart block are presented covering a broad spectrum of clinical presentation, diagnosis, and management both in the fetal and neonatal period. Images Figure 1 PMID:8961692

  10. Modularity maximization using completely positive programming

    NASA Astrophysics Data System (ADS)

    Yazdanparast, Sakineh; Havens, Timothy C.

    2017-04-01

    Community detection is one of the most prominent problems of social network analysis. In this paper, a novel method for Modularity Maximization (MM) for community detection is presented which exploits the Alternating Direction Augmented Lagrangian (ADAL) method for maximizing a generalized form of Newman's modularity function. We first transform Newman's modularity function into a quadratic program and then use Completely Positive Programming (CPP) to map the quadratic program to a linear program, which provides the globally optimal maximum modularity partition. In order to solve the proposed CPP problem, a closed form solution using the ADAL merged with a rank minimization approach is proposed. The performance of the proposed method is evaluated on several real-world data sets used for benchmarks community detection. Simulation results shows the proposed technique provides outstanding results in terms of modularity value for crisp partitions.

  11. Maximally discordant mixed states of two qubits

    SciTech Connect

    Galve, Fernando; Giorgi, Gian Luca; Zambrini, Roberta

    2011-01-15

    We study the relative strength of classical and quantum correlations, as measured by discord, for two-qubit states. Quantum correlations appear only in the presence of classical correlations, while the reverse is not always true. We identify the family of states that maximize the discord for a given value of the classical correlations and show that the largest attainable discord for mixed states is greater than for pure states. The difference between discord and entanglement is emphasized by the remarkable fact that these states do not maximize entanglement and are, in some cases, even separable. Finally, by random generation of density matrices uniformly distributed over the whole Hilbert space, we quantify the frequency of the appearance of quantum and classical correlations for different ranks.

  12. Hamiltonian formalism and path entropy maximization

    NASA Astrophysics Data System (ADS)

    Davis, Sergio; González, Diego

    2015-10-01

    Maximization of the path information entropy is a clear prescription for constructing models in non-equilibrium statistical mechanics. Here it is shown that, following this prescription under the assumption of arbitrary instantaneous constraints on position and velocity, a Lagrangian emerges which determines the most probable trajectory. Deviations from the probability maximum can be consistently described as slices in time by a Hamiltonian, according to a nonlinear Langevin equation and its associated Fokker-Planck equation. The connections unveiled between the maximization of path entropy and the Langevin/Fokker-Planck equations imply that missing information about the phase space coordinate never decreases in time, a purely information-theoretical version of the second law of thermodynamics. All of these results are independent of any physical assumptions, and thus valid for any generalized coordinate as a function of time, or any other parameter. This reinforces the view that the second law is a fundamental property of plausible inference.

  13. Nondecoupling of maximal supergravity from the superstring.

    PubMed

    Green, Michael B; Ooguri, Hirosi; Schwarz, John H

    2007-07-27

    We consider the conditions necessary for obtaining perturbative maximal supergravity in d dimensions as a decoupling limit of type II superstring theory compactified on a (10-d) torus. For dimensions d=2 and d=3, it is possible to define a limit in which the only finite-mass states are the 256 massless states of maximal supergravity. However, in dimensions d>or=4, there are infinite towers of additional massless and finite-mass states. These correspond to Kaluza-Klein charges, wound strings, Kaluza-Klein monopoles, or branes wrapping around cycles of the toroidal extra dimensions. We conclude that perturbative supergravity cannot be decoupled from string theory in dimensions>or=4. In particular, we conjecture that pure N=8 supergravity in four dimensions is in the Swampland.

  14. Experimental implementation of maximally synchronizable networks

    NASA Astrophysics Data System (ADS)

    Sevilla-Escoboza, R.; Buldú, J. M.; Boccaletti, S.; Papo, D.; Hwang, D.-U.; Huerta-Cuellar, G.; Gutiérrez, R.

    2016-04-01

    Maximally synchronizable networks (MSNs) are acyclic directed networks that maximize synchronizability. In this paper, we investigate the feasibility of transforming networks of coupled oscillators into their corresponding MSNs. By tuning the weights of any given network so as to reach the lowest possible eigenratio λN /λ2, the synchronized state is guaranteed to be maintained across the longest possible range of coupling strengths. We check the robustness of the resulting MSNs with an experimental implementation of a network of nonlinear electronic oscillators and study the propagation of the synchronization errors through the network. Importantly, a method to study the effects of topological uncertainties on the synchronizability is proposed and explored both theoretically and experimentally.

  15. Profit Maximization Models for Exponential Decay Processes.

    DTIC Science & Technology

    1980-08-01

    assumptions could easily be analyzed in similar fashion. References [1] Bensoussan, A., Hurst , E.G. and Nislund, B., Management Applications of Modern...TVIPe OF r 04PORNT A i M0 CiH O .V9RAE PROFIT MAXIMIZATION .ODELS FOR EXPONENT IAL Technical Report DECAY PROCESSES August 1990 ~~~I. PtA’OR~idNG ONqG

  16. Maximal respiratory pressures among adolescent swimmers.

    PubMed

    Rocha Crispino Santos, M A; Pinto, M L; Couto Sant'Anna, C; Bernhoeft, M

    2011-01-01

    Maximal inspiratory pressures (MIP) and maximal expiratory pressures (MEP) are useful indices of respiratory muscle strength in athletes. The aims of this study were: to describe the strength of the respiratory muscles of Olympic junior swim team, at baseline and after a standard physical training; and to determine if there is a differential inspiratory and expiratory pressure response to the physical training. A cross-sectional study evaluated 28 international-level swimmers with ages ranging from 15 to 17 years, 19 (61 %) being males. At baseline, MIP was found to be lower in females (P = .001). The mean values reached by males and females were: MIP(cmH2O) = M: 100.4 (± 26.5)/F: 67.8 (± 23.2); MEP (cmH2O) = M: 87.4 (± 20.7)/F: 73.9 (± 17.3). After the physical training they reached: MIP (cmH2O) = M: 95.3 (± 30.3)/F: 71.8 (± 35.6); MEP (cmH2O) = M: 82.8 (± 26.2)/F: 70.4 (± 8.3). No differential pressure responses were observed in either males or females. These results suggest that swimmers can sustain the magnitude of the initial maximal pressures. Other studies should be developed to clarify if MIP and MEP could be used as a marker of an athlete's performance.

  17. Formation Control for the MAXIM Mission

    NASA Technical Reports Server (NTRS)

    Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

    2004-01-01

    Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

  18. Comparison of tests for measuring maximal exercise ability in elite swimmers

    PubMed Central

    Suk, Min-Hwa; Yu, Kyung-Hun; Shin, Yun-A

    2016-01-01

    The purpose of this study was to compare of tests for measuring maximal exercise ability in elite swimmers. The high-school male elite swimmers (n=17) were performed maximal exercise ability tests. The experimental method consisted of a crossover design at 1-week intervals with the swimming tests (field test, water VAMEVAL test, 200-m test, and 400-m test) in random order. It measured the heart rate, ratings of perceived exertion (RPE), and lactate level by physiological factors, and swimming velocity (SV), stroke rate (SR), and stroke length (SL) by mechanical factors. The change of SV, SR, and SL in swimming tests was no significantly different. To compare tests, however, the lactate level and RPE in 200-m test was higher than water VAMEVAL test. The RPE of the 200-m and 400-m tests were higher than the field test and the water VAMEVAL test. Correlations showed between the field test and the 400-m test in heart rate and RPE. Moreover, a correlation observed between the field test and 200-m test in heart rate. In this study, 200-m and 400-m tests were suit to apply the test methods for establishing the exercise intensity appropriate for the underwater training of swimmers. PMID:27419117

  19. Risks for Heart Valve Problems

    MedlinePlus

    ... Cholesterol Tools & Resources Congenital Defects Children & Adults About Congenital Heart Defects The Impact of Congenital Heart Defects Understand Your Risk for Congenital Heart Defects Symptoms & ...

  20. Ivabradine in Management of Heart Failure: a Critical Appraisal.

    PubMed

    Orasanu, Gabriela; Al-Kindi, Sadeer G; Oliveira, Guilherme H

    2016-02-01

    Elevated resting heart rate has been linked to poor outcomes in patients with chronic systolic heart failure. Blockade of funny current channel with ivabradine reduces heart rate without inotropic effects. Ivabradine was recently approved by US Food and Drug Administration for patients with stable, symptomatic chronic heart failure (HF) with left ventricular ejection fraction (LVEF) ≤35 %, who are in sinus rhythm with resting heart rate (HR) ≥ 70 bpm and either are on maximally tolerated doses of beta-blockers, or have a contraindication to beta-blockers. This article will review and evaluate the data supporting the use of ivabradine in patients with HF and explore its mechanisms and physiologic effects.

  1. Use of ratings of perceived exertion for predicting maximal work rate and prescribing exercise intensity in patients taking atenolol.

    PubMed Central

    Eston, R G; Thompson, M

    1997-01-01

    OBJECTIVE: The purpose of this study was to assess the efficacy of Borg's rating of perceived exertion (RPE) scale to predict maximal exercise levels to control exercise intensity in patients taking atenolol for the treatment of essential hypertension. Normally, a standard formula (220-age) is used for calculating a percentage of exercise intensity, but beta blockade can cause reductions in maximal heart rate of between 20 and 30%. METHODS: Patients were split into a control group-10 men and 10 women, aged 50 (SD 12) and 46 (9) respectively, who had risk factors for cardiovascular disease but were not taking any drugs, and a treatment group-11 men and 11 women, aged 53 (13) and 55 (13) respectively, who were established on 25-100 mg of atenolol. All patients performed two submaximal tests on a cycle ergometer. Test 1 was an estimation test, during which the RPE was reported for each increment in work rate. Test 2 was an RPE production test, during which the patient regulated the work rate according to his/her perception of effort at four predetermined points on the RPE scale (RPE 9, 13, 15, 17). RESULTS: In both tests the individual correlations (r) between RPE, heart rate, and work rate ranged from 0.96 to 0.99. Analysis of variance showed no significant difference in maximal heart rate and maximal power output for the control group when predicted from the regression lines of RPE versus heart rate and RPE versus power output in the estimation test. However, the prediction of maximal power output was lower in the women in the control group and patients in the treatment group when this was predicted from the effort production protocol (P < 0.01). When exercise intensity at each RPE was expressed relative to maximal power output there were no differences between treatment and control groups. CONCLUSION: The findings from this study confirmed the strong positive relation between RPE, heart rate, and work rate in these patients in both passive effort estimation and

  2. Maximizing versus satisficing: happiness is a matter of choice.

    PubMed

    Schwartz, Barry; Ward, Andrew; Monterosso, John; Lyubomirsky, Sonja; White, Katherine; Lehman, Darrin R

    2002-11-01

    Can people feel worse off as the options they face increase? The present studies suggest that some people--maximizers--can. Study 1 reported a Maximization Scale, which measures individual differences in desire to maximize. Seven samples revealed negative correlations between maximization and happiness, optimism, self-esteem, and life satisfaction, and positive correlations between maximization and depression, perfectionism, and regret. Study 2 found maximizers less satisfied than nonmaximizers (satisficers) with consumer decisions, and more likely to engage in social comparison. Study 3 found maximizers more adversely affected by upward social comparison. Study 4 found maximizers more sensitive to regret and less satisfied in an ultimatum bargaining game. The interaction between maximizing and choice is discussed in terms of regret, adaptation, and self-blame.

  3. Postactivation Potentiation Biases Maximal Isometric Strength Assessment

    PubMed Central

    Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Oliveira, Thiago Pires; Assumpção, Claudio de Oliveira; Greco, Camila Coelho; Cardozo, Adalgiso Croscato; Denadai, Benedito Sérgio

    2014-01-01

    Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s−1versus 727 ± 158 N·m·s−1), and RMS (59.1 ± 12.2% RMSMAX  versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables. PMID:25133157

  4. Electromagnetically induced grating with maximal atomic coherence

    SciTech Connect

    Carvalho, Silvania A.; Araujo, Luis E. E. de

    2011-10-15

    We describe theoretically an atomic diffraction grating that combines an electromagnetically induced grating with a coherence grating in a double-{Lambda} atomic system. With the atom in a condition of maximal coherence between its lower levels, the combined gratings simultaneously diffract both the incident probe beam as well as the signal beam generated through four-wave mixing. A special feature of the atomic grating is that it will diffract any beam resonantly tuned to any excited state of the atom accessible by a dipole transition from its ground state.

  5. Maximizing algebraic connectivity in air transportation networks

    NASA Astrophysics Data System (ADS)

    Wei, Peng

    In air transportation networks the robustness of a network regarding node and link failures is a key factor for its design. An experiment based on the real air transportation network is performed to show that the algebraic connectivity is a good measure for network robustness. Three optimization problems of algebraic connectivity maximization are then formulated in order to find the most robust network design under different constraints. The algebraic connectivity maximization problem with flight routes addition or deletion is first formulated. Three methods to optimize and analyze the network algebraic connectivity are proposed. The Modified Greedy Perturbation Algorithm (MGP) provides a sub-optimal solution in a fast iterative manner. The Weighted Tabu Search (WTS) is designed to offer a near optimal solution with longer running time. The relaxed semi-definite programming (SDP) is used to set a performance upper bound and three rounding techniques are discussed to find the feasible solution. The simulation results present the trade-off among the three methods. The case study on two air transportation networks of Virgin America and Southwest Airlines show that the developed methods can be applied in real world large scale networks. The algebraic connectivity maximization problem is extended by adding the leg number constraint, which considers the traveler's tolerance for the total connecting stops. The Binary Semi-Definite Programming (BSDP) with cutting plane method provides the optimal solution. The tabu search and 2-opt search heuristics can find the optimal solution in small scale networks and the near optimal solution in large scale networks. The third algebraic connectivity maximization problem with operating cost constraint is formulated. When the total operating cost budget is given, the number of the edges to be added is not fixed. Each edge weight needs to be calculated instead of being pre-determined. It is illustrated that the edge addition and the

  6. Approximation Algorithms for Free-Label Maximization

    NASA Astrophysics Data System (ADS)

    de Berg, Mark; Gerrits, Dirk H. P.

    Inspired by air traffic control and other applications where moving objects have to be labeled, we consider the following (static) point labeling problem: given a set P of n points in the plane and labels that are unit squares, place a label with each point in P in such a way that the number of free labels (labels not intersecting any other label) is maximized. We develop efficient constant-factor approximation algorithms for this problem, as well as PTASs, for various label-placement models.

  7. Maximizing results in reconstruction of cheek defects.

    PubMed

    Mureau, Marc A M; Hofer, Stefan O P

    2009-07-01

    The face is exceedingly important, as it is the medium through which individuals interact with the rest of society. Reconstruction of cheek defects after trauma or surgery is a continuing challenge for surgeons who wish to reliably restore facial function and appearance. Important in aesthetic facial reconstruction are the aesthetic unit principles, by which the face can be divided in central facial units (nose, lips, eyelids) and peripheral facial units (cheeks, forehead, chin). This article summarizes established options for reconstruction of cheek defects and provides an overview of several modifications as well as tips and tricks to avoid complications and maximize aesthetic results.

  8. Developing maximal neuromuscular power: part 2 - training considerations for improving maximal power production.

    PubMed

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2011-02-01

    This series of reviews focuses on the most important neuromuscular function in many sport performances: the ability to generate maximal muscular power. Part 1, published in an earlier issue of Sports Medicine, focused on the factors that affect maximal power production while part 2 explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability to generate maximal power during complex motor skills is of paramount importance to successful athletic performance across many sports. A crucial issue faced by scientists and coaches is the development of effective and efficient training programmes that improve maximal power production in dynamic, multi-joint movements. Such training is referred to as 'power training' for the purposes of this review. Although further research is required in order to gain a deeper understanding of the optimal training techniques for maximizing power in complex, sports-specific movements and the precise mechanisms underlying adaptation, several key conclusions can be drawn from this review. First, a fundamental relationship exists between strength and power, which dictates that an individual cannot possess a high level of power without first being relatively strong. Thus, enhancing and maintaining maximal strength is essential when considering the long-term development of power. Second, consideration of movement pattern, load and velocity specificity is essential when designing power training programmes. Ballistic, plyometric and weightlifting exercises can be used effectively as primary exercises within a power training programme that enhances maximal power. The loads applied to these exercises will depend on the specific requirements of each particular sport and the type of movement being trained. The use of ballistic exercises with loads ranging from 0% to 50% of one-repetition maximum (1RM) and

  9. Heart transplantation in adult congenital heart disease.

    PubMed

    Burchill, Luke J

    2016-12-01

    Heart failure (HF) in adult congenital heart disease (ACHD) is vastly different to that observed in acquired heart disease. Unlike acquired HF in which pharmacological strategies are the cornerstone for protecting and improving ventricular function, ACHD-related HF relies heavily upon structural and other interventions to achieve these aims. patients with ACHD constitute a small percentage of the total adult heart transplant population (∼3%), although the number of ACHD heart transplant recipients is growing rapidly with a 40% increase over the last two decades. The worldwide experience to date has confirmed heart transplantation as an effective life-extending treatment option in carefully selected patients with ACHD with end-stage cardiac disease. Opportunities for improving outcomes in patients with ACHD-related HF include (i) earlier recognition and referral to centres with combined expertise in ACHD and HF, (ii) increased awareness of arrhythmia and sudden cardiac death risk in this population, (iii) greater collaboration between HF and ACHD specialists at the time of heart transplant assessment, (iv) expert surgical planning to reduce ischaemic time and bleeding risk at the time of transplant, (v) tailored immunosuppression in the post-transplant period and (vi) development and validation of ACHD-specific risk scores to predict mortality and guide patient selection. The purpose of this article is to review current approaches to diagnosing and treating advanced HF in patients with ACHD including indications, contraindications and clinical outcomes after heart transplantation.

  10. How Can I Live with Heart Failure?

    MedlinePlus

    ... Understand Your Risk for Congenital Heart Defects Symptoms & Diagnosis of Congenital Heart Defects Care & Treatment for Congenital Heart Defects Congenital Heart Defects Tools & Resources Heart Attack About Heart Attacks Warning Signs of a Heart ...

  11. Heart PET scan

    MedlinePlus

    Heart nuclear medicine scan; Heart positron emission tomography; Myocardial PET scan ... Udelson JE, Dilsizian V, Bonow RO. Nuclear cardiology. In: Mann DL, ... A Textbook of Cardiovascular Medicine . 10th ed. Philadelphia, ...

  12. Inflammation and Heart Disease

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Inflammation and Heart Disease Updated:Oct 12,2016 Understand the risks of ... inflammation causes cardiovascular disease, inflammation is common for heart disease and stroke patients and is thought to be ...

  13. Heart disease - risk factors

    MedlinePlus

    Heart disease - prevention; CVD - risk factors; Cardiovascular disease - risk factors; Coronary artery disease - risk factors; CAD - risk ... a certain health condition. Some risk factors for heart disease you cannot change, but some you can. ...

  14. Heart bypass surgery

    MedlinePlus

    Off-pump coronary artery bypass; OPCAB; Beating heart surgery; Bypass surgery - heart; CABG; Coronary artery bypass graft; Coronary artery bypass surgery; Coronary bypass surgery; Coronary artery disease - CABG; CAD - CABG; Angina - ...

  15. Problem: Heart Valve Regurgitation

    MedlinePlus

    ... Options • Recovery and Healthy Living Goals • Personal Stories Heart Valve Disease Symptoms Dr. Robert Bonow describes the symptoms that may alert you to heart valve disease. Support Network: You're Not Alone Popular Articles ...

  16. Nuclear Heart Scan

    MedlinePlus

    ... into your blood and travels to your heart. Nuclear heart scans use single photon emission computed tomography (SPECT) or cardiac positron emission tomography (PET) to detect the energy from the tracer to make pictures of your ...

  17. Congenital Heart Defects

    MedlinePlus

    ... Treatment can include medicines, catheter procedures, surgery, and heart transplants. The treatment depends on the type of the defect, how severe it is, and a child's age, size, and general health. NIH: National Heart, Lung, and Blood Institute

  18. Heart failure - discharge

    MedlinePlus

    ... Heart failure - overview Heart pacemaker High blood pressure Implantable cardioverter-defibrillator Smoking - tips on how to quit ... ask your doctor How to read food labels Implantable cardioverter defibrillator - discharge Low-salt diet Mediterranean diet ...

  19. Menopause and Heart Disease

    MedlinePlus

    ... minutes, you can get your own personal heart score and life plan. Live better with Life's Simple ... and wellness. Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Target Heart Rates ...

  20. Know Your Heart's Numbers

    MedlinePlus

    ... of body fat based on height and weight), waist circumference, blood sugar and weight. The telephone survey of ... for heart health. Just 36 percent knew that waist circumference is important measure of heart disease risk. The ...

  1. Heart attack - discharge

    MedlinePlus

    ... syndromes: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. ... disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice ...

  2. Tachycardia | Fast Heart Rate

    MedlinePlus

    ... heart disease and stroke. Start exploring today ! Printable Arrhythmia Information Sheets What is Arrhythmia? What is Atrial ... Card See all Answers by Heart patient sheets Arrhythmia • Home • About Arrhythmia Introduction Atrial Fibrillation Bradycardia Conduction ...

  3. Types of Heart Surgery

    MedlinePlus

    ... conditions that make open-heart surgery very risky. Arrhythmia Treatment An arrhythmia (ah-RITH-me-ah) is a problem with ... rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, ...

  4. American Heart Association

    MedlinePlus

    ... Educator CPR & ECC Shop Causes Advocate Giving Media American Heart Association Check out Scientific Sessions 2016 news -- translated for ... do not always represent the views of the American Heart Association. Keep color fresh and vibrant by knowing how ...

  5. Overview of Heart Tumors

    MedlinePlus

    ... the heart. Most heart tumors are metastatic cancer. Did You Know... Noncancerous tumors can be as deadly ... slow the tumor's growth. Resources In This Article Did You Know 1 Did You Know... Table 2 ...

  6. Men and Heart Disease

    MedlinePlus

    ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ...

  7. Heart Disease Risk Factors

    MedlinePlus

    ... this? Submit What's this? Submit Button Related CDC Web Sites Division for Heart Disease and Stroke Prevention ... this? Submit What's this? Submit Button Related CDC Web Sites Division for Heart Disease and Stroke Prevention ...

  8. Heart failure - tests

    MedlinePlus

    CHF - tests; Congestive heart failure - tests; Cardiomyopathy - tests; HF - tests ... An echocardiogram (Echo) is a test that uses sound waves to create a moving picture of the heart. The picture is much more detailed than a plain ...

  9. How the Heart Works

    MedlinePlus

    ... Your heart is at the center of your circulatory system. This system consists of a network of blood ... the walls contract, blood is pumped into your circulatory system. Inlet and outlet valves in your heart chambers ...

  10. Heart and Stroke Encyclopedia

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More The Heart and Stroke Encyclopedia Click a letter below to get a ... dozens of cardiovascular terms from our Heart and Stroke Encyclopedia and get links to in-depth information. ...

  11. Heart Murmurs (For Kids)

    MedlinePlus

    ... Dictionary of Medical Words En Español What Other Kids Are Reading Taking Care of Your Ears Taking ... Getting an X-ray Heart Murmurs KidsHealth > For Kids > Heart Murmurs Print A A A What's in ...

  12. About Heart Attacks

    MedlinePlus

    ... called plaque. This slow process is known as atherosclerosis . When a plaque in a heart artery breaks, ... called plaque. This slow process is known as atherosclerosis . When a plaque in a heart artery breaks, ...

  13. Congenital heart disease

    MedlinePlus

    ... defect - heartbeat Patent ductus arteriosis (PDA) - series References Fraser CD, Carberry KE. Congenital heart disease. In: Townsend ... ASD) Coarctation of the aorta Ellis-van Creveld syndrome Fetal alcohol syndrome Hypoplastic left heart syndrome Marfan ...

  14. Pericarditis - after heart attack

    MedlinePlus

    ... medlineplus.gov/ency/article/000166.htm Pericarditis - after heart attack To use the sharing features on this page, ... occur in the days or weeks following a heart attack . Causes Two types of pericarditis can occur after ...

  15. [Understanding heart failure].

    PubMed

    Boo, José Fernando Guadalajara

    2006-01-01

    Heart failure is a disease with several definitions. The term "heart failure" is used by has brougth about confusion in the terminology. For this reason, the value of the ejection fraction (< 0.40 or < 0.35) is used in most meganalyses on the treatment of heart failure, avoiding the term "heart failure" that is a confounding concept. In this paper we carefully analyze the meaning of contractility, ventricular function or performance, preload, afterload, heart failure, compensation mechanisms in heart failure, myocardial oxygen consumption, inadequate, adequate and inappropriate hypertrophy, systole, diastole, compliance, problems of relaxation, and diastolic dysfunction. Their definitions are supported by the original scientific descriptions in an attempt to clarify the concepts about ventricular function and heart failure and, in this way, use the same scientific language about the meaning of ventricular function, heart failure, and diastolic dysfunction.

  16. Optimizing Population Variability to Maximize Benefit

    PubMed Central

    Izu, Leighton T.; Bányász, Tamás; Chen-Izu, Ye

    2015-01-01

    Variability is inherent in any population, regardless whether the population comprises humans, plants, biological cells, or manufactured parts. Is the variability beneficial, detrimental, or inconsequential? This question is of fundamental importance in manufacturing, agriculture, and bioengineering. This question has no simple categorical answer because research shows that variability in a population can have both beneficial and detrimental effects. Here we ask whether there is a certain level of variability that can maximize benefit to the population as a whole. We answer this question by using a model composed of a population of individuals who independently make binary decisions; individuals vary in making a yes or no decision, and the aggregated effect of these decisions on the population is quantified by a benefit function (e.g. accuracy of the measurement using binary rulers, aggregate income of a town of farmers). Here we show that an optimal variance exists for maximizing the population benefit function; this optimal variance quantifies what is often called the “right mix” of individuals in a population. PMID:26650247

  17. Fractional stereo matching using expectation-maximization.

    PubMed

    Xiong, Wei; Chung, Hin Shun; Jia, Jiaya

    2009-03-01

    In our fractional stereo matching problem, a foreground object with a fractional boundary is blended with a background scene using unknown transparencies. Due to the spatially varying disparities in different layers, one foreground pixel may be blended with different background pixels in stereo images, making the color constancy commonly assumed in traditional stereo matching not hold any more. To tackle this problem, in this paper, we introduce a probabilistic framework constraining the matching of pixel colors, disparities, and alpha values in different layers, and propose an automatic optimization method to solve a Maximizing a Posterior (MAP) problem using Expectation-Maximization (EM), given only a short-baseline stereo input image pair. Our method encodes the effect of background occlusion by layer blending without requiring a special detection process. The alpha computation process in our unified framework can be regarded as a new approach by natural image matting, which handles appropriately the situation when the background color is similar to that of the foreground object. We demonstrate the efficacy of our method by experimenting with challenging stereo images and making comparisons with state-of-the-art methods.

  18. Maximal liquid bridges between horizontal cylinders.

    PubMed

    Cooray, Himantha; Huppert, Herbert E; Neufeld, Jerome A

    2016-08-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace-Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity.

  19. Maximal liquid bridges between horizontal cylinders

    NASA Astrophysics Data System (ADS)

    Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A.

    2016-08-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace-Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity.

  20. Maximizing strain in miniaturized dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Rosset, Samuel; Araromi, Oluwaseun; Shea, Herbert

    2015-04-01

    We present a theoretical model to optimise the unidirectional motion of a rigid object bonded to a miniaturized dielectric elastomer actuator (DEA), a configuration found for example in AMI's haptic feedback devices, or in our tuneable RF phase shifter. Recent work has shown that unidirectional motion is maximized when the membrane is both anistropically prestretched and subjected to a dead load in the direction of actuation. However, the use of dead weights for miniaturized devices is clearly highly impractical. Consequently smaller devices use the membrane itself to generate the opposing force. Since the membrane covers the entire frame, one has the same prestretch condition in the active (actuated) and passive zones. Because the passive zone contracts when the active zone expands, it does not provide a constant restoring force, reducing the maximum achievable actuation strain. We have determined the optimal ratio between the size of the electrode (active zone) and the passive zone, as well as the optimal prestretch in both in-plane directions, in order to maximize the absolute displacement of the rigid object placed at the active/passive border. Our model and experiments show that the ideal active ratio is 50%, with a displacement twice smaller than what can be obtained with a dead load. We expand our fabrication process to also show how DEAs can be laser-post-processed to remove carefully chosen regions of the passive elastomer membrane, thereby increasing the actuation strain of the device.

  1. Maximal lactate steady state in Judo

    PubMed Central

    de Azevedo, Paulo Henrique Silva Marques; Pithon-Curi, Tania; Zagatto, Alessandro Moura; Oliveira, João; Perez, Sérgio

    2014-01-01

    Summary Background: the purpose of this study was to verify the validity of respiratory compensation threshold (RCT) measured during a new single judo specific incremental test (JSIT) for aerobic demand evaluation. Methods: to test the validity of the new test, the JSIT was compared with Maximal Lactate Steady State (MLSS), which is the gold standard procedure for aerobic demand measuring. Eight well-trained male competitive judo players (24.3 ± 7.9 years; height of 169.3 ± 6.7cm; fat mass of 12.7 ± 3.9%) performed a maximal incremental specific test for judo to assess the RCT and performed on 30-minute MLSS test, where both tests were performed mimicking the UchiKomi drills. Results: the intensity at RCT measured on JSIT was not significantly different compared to MLSS (p=0.40). In addition, it was observed high and significant correlation between MLSS and RCT (r=0.90, p=0.002), as well as a high agreement. Conclusions: RCT measured during JSIT is a valid procedure to measure the aerobic demand, respecting the ecological validity of Judo. PMID:25332923

  2. Optimizing Population Variability to Maximize Benefit.

    PubMed

    Izu, Leighton T; Bányász, Tamás; Chen-Izu, Ye

    2015-01-01

    Variability is inherent in any population, regardless whether the population comprises humans, plants, biological cells, or manufactured parts. Is the variability beneficial, detrimental, or inconsequential? This question is of fundamental importance in manufacturing, agriculture, and bioengineering. This question has no simple categorical answer because research shows that variability in a population can have both beneficial and detrimental effects. Here we ask whether there is a certain level of variability that can maximize benefit to the population as a whole. We answer this question by using a model composed of a population of individuals who independently make binary decisions; individuals vary in making a yes or no decision, and the aggregated effect of these decisions on the population is quantified by a benefit function (e.g. accuracy of the measurement using binary rulers, aggregate income of a town of farmers). Here we show that an optimal variance exists for maximizing the population benefit function; this optimal variance quantifies what is often called the "right mix" of individuals in a population.

  3. Spiders Tune Glue Viscosity to Maximize Adhesion.

    PubMed

    Amarpuri, Gaurav; Zhang, Ci; Diaz, Candido; Opell, Brent D; Blackledge, Todd A; Dhinojwala, Ali

    2015-11-24

    Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities that matches their foraging habitats. By using high-speed imaging and spreading power law, we find that the glue viscosity varies over 5 orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10(5)-10(6) cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by a combination of proteins and hygroscopic organic salts that determines water uptake in the glue. We therefore anticipate that manipulation of polymer-salts interaction to control viscosity can provide a simple mechanism to design humidity responsive smart adhesives.

  4. Maximal coherence in a generic basis

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Dong, G. H.; Ge, Li; Li, Mo; Sun, C. P.

    2016-12-01

    Since quantum coherence is an undoubted characteristic trait of quantum physics, the quantification and application of quantum coherence has been one of the long-standing central topics in quantum information science. Within the framework of a resource theory of quantum coherence proposed recently, a fiducial basis should be preselected for characterizing the quantum coherence in specific circumstances, namely, the quantum coherence is a basis-dependent quantity. Therefore, a natural question is raised: what are the maximum and minimum coherences contained in a certain quantum state with respect to a generic basis? While the minimum case is trivial, it is not so intuitive to verify in which basis the quantum coherence is maximal. Based on the coherence measure of relative entropy, we indicate the particular basis in which the quantum coherence is maximal for a given state, where the Fourier matrix (or more generally, complex Hadamard matrices) plays a critical role in determining the basis. Intriguingly, though we can prove that the basis associated with the Fourier matrix is a stationary point for optimizing the l1 norm of coherence, numerical simulation shows that it is not a global optimal choice.

  5. Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Shibasaki, M.; Wilson, T. E.; Cui, J.; Levine, B. D.

    2003-01-01

    Cutaneous vasodilation and sweat rate are reduced during a thermal challenge after simulated and actual microgravity exposure. The effects of microgravity exposure on cutaneous vasodilator capacity and on sweat gland function are unknown. The purpose of this study was to test the hypothesis that simulated microgravity exposure, using the 6 degrees head-down tilt (HDT) bed rest model, reduces maximal forearm cutaneous vascular conductance (FVC) and sweat gland function and that exercise during HDT preserves these responses. To test these hypotheses, 20 subjects were exposed to 14 days of strict HDT bed rest. Twelve of those subjects exercised (supine cycle ergometry) at 75% of pre-bed rest heart rate maximum for 90 min/day throughout HDT bed rest. Before and after HDT bed rest, maximal FVC was measured, via plethysmography, by heating the entire forearm to 42 degrees C for 45 min. Sweat gland function was assessed by administering 1 x 10(-6) to 2 M acetylcholine (9 doses) via intradermal microdialysis while simultaneously monitoring sweat rate over the microdialysis membranes. In the nonexercise group, maximal FVC and maximal stimulated sweat rate were significantly reduced after HDT bed rest. In contrast, these responses were unchanged in the exercise group. These data suggest that 14 days of simulated microgravity exposure, using the HDT bed rest model, reduces cutaneous vasodilator and sweating capacity, whereas aerobic exercise training during HDT bed rest preserves these responses.

  6. Potential benefits of maximal exercise just prior to return from weightlessness

    SciTech Connect

    Convertino, V.A.

    1987-06-01

    The purpose of this study was to determine whether performance of a single maximal bout of exercise during weightlessness within hours of return to earth would enhance recovery of aerobic fitness and physical work capacities under a 1G environment. Ten healthy men were subjected to a 10-d bedrest period in the 6-deg headdown position. A graded maximal supine cycle ergometer test was performed before and at the end of bedrest to simulate exercise during weightlessness. Following 3 h of resumption of the upright posture, a second maximal exercise test was performed on a treadmill to measure work capacity under conditions of 1G. Compared to before bedrest, peak oxygen consumption, V(O/sub 2/), decreased by 8.7 percent and peak heart rate (HR) increased by 5.6 percent in the supine cycle test at the end of bedrest. However, there were no significant changes in peak V(O/sub 2/) and peak HR in the upright treadmill test following bedrest. These data suggest that one bout of maximal leg exercise prior to return from 10 d of weightlessness may be adequate to restore preflight aerobic fitness and physical work capacity. 26 references.

  7. Potential benefits of maximal exercise just prior to return from weightlessness

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.

    1987-01-01

    The purpose of this study was to determine whether performance of a single maximal bout of exercise during weightlessness within hours of return to earth would enhance recovery of aerobic fitness and physical work capacities under a 1G environment. Ten healthy men were subjected to a 10-d bedrest period in the 6-deg headdown position. A graded maximal supine cycle ergometer test was performed before and at the end of bedrest to simulate exercise during weightlessness. Following 3 h of resumption of the upright posture, a second maximal exercise test was performed on a treadmill to measure work capacity under conditions of 1G. Compared to before bedrest, peak oxygen consumption, V(O2), decreased by 8.7 percent and peak heart rate (HR) increased by 5.6 percent in the supine cycle test at the end of bedrest. However, there were no significant changes in peak V(O2) and peak HR in the upright treadmill test following bedrest. These data suggest that one bout of maximal leg exercise prior to return from 10 d of weightlessness may be adequate to restore preflight aerobic fitness and physical work capacity.

  8. How Is Heart Failure Diagnosed?

    MedlinePlus

    ... in a pocket, or hung around your neck. Nuclear Heart Scan A nuclear heart scan shows how well blood is flowing ... blood is reaching your heart muscle. During a nuclear heart scan, a safe, radioactive substance called a ...

  9. Congenital Heart Disease in Adults

    MedlinePlus

    ... and genetics may play a role. Why congenital heart disease resurfaces in adulthood Some adults may find that ... in following adults with congenital heart disease. Congenital heart disease and pregnancy Women with congenital heart disease who ...

  10. Living with Heart Valve Disease

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Heart Valve Disease Heart valve disease is a lifelong condition. However, ... all of your medicines as prescribed. Pregnancy and Heart Valve Disease Mild or moderate heart valve disease during pregnancy ...

  11. Heart Disease and Stroke Prevention

    MedlinePlus

    ... Heart disease and stroke prevention Heart Health and Stroke Heart disease and stroke prevention Related information Learn more about healthy eating ... to top More information on Heart disease and stroke prevention Read more from womenshealth.gov A Lifetime ...

  12. Life After a Heart Attack

    MedlinePlus

    ... from the NHLBI on Twitter. Life After a Heart Attack Many people survive heart attacks and live active, ... a few weeks. Anxiety and Depression After a Heart Attack After a heart attack, many people worry about ...

  13. What Is a Heart Attack?

    MedlinePlus

    ... from the NHLBI on Twitter. What Is a Heart Attack? Español A heart attack happens when the flow ... This Content: NEXT >> Featured Video What is a heart attack? 05/22/2014 Describes how a heart attack ...

  14. What Happens After Heart Surgery?

    MedlinePlus

    ANSWERS by heart Treatments + Tests What Happens After Heart Surgery? What are the ICU and CCU? In a ... doctors. This is where patients go after open-heart surgery or a heart attack. You’re watched around ...

  15. Heart Disease in Women

    MedlinePlus

    ... United States, 1 in 4 women dies from heart disease. The most common cause of heart disease in both men and women is narrowing ... the blood vessels that supply blood to the heart itself. This is called coronary artery disease, and ...

  16. The Heart of Coaching

    ERIC Educational Resources Information Center

    Docheff, Dennis M.; Gerdes, Dan

    2015-01-01

    This article challenges coaches to address the more personal, human elements of coaching--the HEART of coaching. While there is much research on numerous aspects of coaching, this article provides ideas that make a lasting impact on the hearts of athletes. Using HEART as an acronym, five elements of effective coaching are presented: Humility,…

  17. Heart Valve Diseases

    MedlinePlus

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  18. Working Model Hearts

    ERIC Educational Resources Information Center

    Brock, David

    2009-01-01

    Despite student interest, the heart is often a poorly understood topic in biology. To help students understand this vital organ's physiology, the author created this investigation activity involving the mammalian heart and its role in the circulatory system. Students design, build, and demonstrate working artificial "hearts" to exhibit what they…

  19. Heart bypass surgery

    MedlinePlus Videos and Cool Tools

    Heart bypass surgery begins with an incision made in the chest, with the breastbone cut exposing the heart. Next, a portion of the saphenous vein is ... used to bypass the blocked arteries in the heart. The venous graft is sewn to the aorta ...

  20. Cancer and the heart

    SciTech Connect

    Kapoor, A.S.

    1986-01-01

    This book contains 28 chapters. Some of the titles are: Computed tomography of neoplastic disease of the pericardium; Radiation therapy and the heart; Valvular involvement in cancer; Smoking, lung cancer, and coronary heart disease; Carcinoid heart disease; Cardiac amyloidosis; and Anemia of cancer and its cardiac effects.

  1. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  2. Determination of maximal oxygen uptake using the bruce or a novel athlete-led protocol in a mixed population.

    PubMed

    Hamlin, Michael J; Draper, Nick; Blackwell, Gavin; Shearman, Jeremy P; Kimber, Nicholas E

    2012-03-01

    Treadmill tests for maximal oxygen uptake (V̇O2max) have traditionally used set speed and incline increments regardless of participants training or exercise background. The aim of this study was to determine the validity of a novel athlete-led protocol for determining maximal aerobic fitness in adults. Twenty-nine participants (21 male, 8 female, age 29.8 ± 9.5 y, BMI 24.4 ± 3.1, mean ± SD) from a variety of exercise backgrounds were asked to complete two maximal treadmill running tests (using the standard Bruce or a novel athlete-led protocol [ALP]) to volitional failure in a counter-balanced randomised cross-over trial one week apart. We found no substantial difference in maximal oxygen uptake (47.0 ± 9.1 and 46.8 ± 10.7 ml·kg(-1)·min(-1), mean ± SD for the ALP and Bruce protocols respectively), evidenced by the Spearman correlation coefficient of 0.93 (90% confidence limits, 0.88-0.96). However, compared to the Bruce protocol, participants completing the ALP protocol attained a substantially higher maximal heart rate (ALP = 182.8 ± 10.5, Bruce = 179.7 ± 8.7 beats·min(-1)). Additionally, using the Bruce protocol took a longer period of time (23.2 ± 17.0 s) compared to the ALP protocol. It seems that using either treadmill protocol will give you similar maximal oxygen uptake results. We suggest the ALP protocol which is simpler, quicker and probably better at achieving maximal heart rates is a useful alternative to the traditional Bruce protocol.

  3. A comparison between laddermill and treadmill maximal oxygen consumption.

    PubMed

    Montoliu, M A; Gonzalez, V; Rodriguez, B; Palenciano, L

    1997-01-01

    Maximal O2 consumption (VO2max) is an index of the capacity for work over an 8 h workshift. Running on a treadmill is the most common method of eliciting it, because it is an easy, natural exercise, and also, by engaging large muscle masses, larger values are obtained than by other exercises. It has been claimed, however, that climbing a laddermill elicits a still higher VO2max, probably because more muscle mass is apparently engaged (legs + arms) than on the treadmill (legs only). However, no data in support of this claim have been presented. To see if differences exist, we conducted progressive tests to exhaustion on 44 active coal miners, on a laddermill (slant angle 75 degrees, vertical separation of rungs 25 cm) and on a treadmill set at a 5% gradient. The subjects' mean (range) age was 37.4 (31-47) years, height 174.3 (164-187) cm, body mass 82.2 (64-103) kg. Mean (range) VO2max on the laddermill was 2.83 (2.31-3.64) l x min(-1) and 2.98 (2.03-4.22) l x min(-1) on the treadmill (P < 0.01, Student's paired t-test). Mean (range) of maximal heart rate f(cmax) (beats x min(-1)) on the laddermill and on the treadmill were 181.0 (161-194) and 181.3 (162-195), respectively (NS). Laddermill:treadmill VO2max was negatively related to both treadmill VO2max x kg body mass(-1) (r = -0.410, P < 0.01) and body mass (r = -0.409, P < 0.01). Laddermill:treadmill f(cmax) was negatively related to treadmill VO2max x kg body mass(-1) (r = -0.367, P < 0.02) but not to body mass (r = -0.166, P = 0.28). Our data would suggest that for fitter subjects (VO2max > 2.6 l x min or VO2max kg body mass(-1) > 30 ml x min(-1) x kg(-1)) and/or higher body masses (> 70 kg), exercise on the laddermill is not dynamic enough to elicit a VO2max as high as on the treadmill. For such subjects, treadmill VO2max would overestimate exercise capacity for jobs requiring a fair amount of climbing ladders or ladder-like structures.

  4. Heart Failure: A Primer.

    PubMed

    Lee, Christopher S; Auld, Jonathan

    2015-12-01

    Heart failure is a complex and multisystem clinical syndrome that results from impaired ventricular contractility and/or relaxation. Hypertension, diabetes mellitus, and coronary artery disease are common antecedents to heart failure. The main pathogenic mechanisms involved in heart failure include sympathetic nervous and renin-angiotensin-aldosterone system activation, as well as inflammation. A detailed history and physical examination and additional diagnostic tests may be needed to diagnose heart failure. Most treatment strategies target neurohormonal systems. Nonpharmacologic interventions and effective engagement in self-care are also important in overall heart failure management. Therapeutic strategies are geared toward prolonging life and optimizing quality of life.

  5. Maximal energy extraction under discrete diffusive exchange

    SciTech Connect

    Hay, M. J.; Schiff, J.; Fisch, N. J.

    2015-10-15

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  6. Maximal energy extraction under discrete diffusive exchange

    NASA Astrophysics Data System (ADS)

    Hay, M. J.; Schiff, J.; Fisch, N. J.

    2015-10-01

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  7. Multipartite maximally entangled states in symmetric scenarios

    NASA Astrophysics Data System (ADS)

    González-Guillén, Carlos E.

    2012-08-01

    We consider the class of (N+1)-partite states suitable for protocols where there is a powerful party, the authority, and the other N parties play the same role, namely, the state of their system lies in the symmetric Hilbert space. We show that, within this scenario, there is a “maximally entangled state” that can be transform by a local operations and classical communication protocol into any other state. In addition, we show how to use the protocol efficiently, including the construction of the state, and discuss security issues for possible applications to cryptographic protocols. As an immediate consequence we recover a sequential protocol that implements the 1-to-N symmetric cloning.

  8. Polycrystalline configurations that maximize electrical resistivity

    NASA Astrophysics Data System (ADS)

    Nesi, Vincenzo; Milton, Graeme W.

    A lower bound on the effective conductivity tensor of polycrystalline aggregates formed from a single basic crystal of conductivity σ was recently established by Avellaneda. Cherkaev, Lurie and Milton. The bound holds for any basic crystal, but for isotropic aggregates of a uniaxial crystal, the bound is achieved by a sphere assemblage model of Schulgasser. This left open the question of attainability of the bound when the crystal is not uniaxial. The present work establishes that the bound is always attained by a rather large class of polycrystalline materials. These polycrystalline materials, with maximal electrical resistivity, are constructed by sequential lamination of the basic crystal and rotations of itself on widely separated length scales. The analysis is facilitated by introducing a tensor S = 0( 0I + σ) -1 where 0 > 0 is chosen so that Tr S = 1. This tensor s is related to the electric field in the optimal polycrystalline configurations.

  9. Dispatch Scheduling to Maximize Exoplanet Detection

    NASA Astrophysics Data System (ADS)

    Johnson, Samson; McCrady, Nate; MINERVA

    2016-01-01

    MINERVA is a dedicated exoplanet detection telescope array using radial velocity measurements of nearby stars to detect planets. MINERVA will be a completely robotic facility, with a goal of maximizing the number of exoplanets detected. MINERVA requires a unique application of queue scheduling due to its automated nature and the requirement of high cadence observations. A dispatch scheduling algorithm is employed to create a dynamic and flexible selector of targets to observe, in which stars are chosen by assigning values through a weighting function. I designed and have begun testing a simulation which implements the functions of a dispatch scheduler and records observations based on target selections through the same principles that will be used at the commissioned site. These results will be used in a larger simulation that incorporates weather, planet occurrence statistics, and stellar noise to test the planet detection capabilities of MINERVA. This will be used to heuristically determine an optimal observing strategy for the MINERVA project.

  10. Characterizing maximally singular phase-space distributions

    NASA Astrophysics Data System (ADS)

    Sperling, J.

    2016-07-01

    Phase-space distributions are widely applied in quantum optics to access the nonclassical features of radiations fields. In particular, the inability to interpret the Glauber-Sudarshan distribution in terms of a classical probability density is the fundamental benchmark for quantum light. However, this phase-space distribution cannot be directly reconstructed for arbitrary states, because of its singular behavior. In this work, we perform a characterization of the Glauber-Sudarshan representation in terms of distribution theory. We address important features of such distributions: (i) the maximal degree of their singularities is studied, (ii) the ambiguity of representation is shown, and (iii) their dual space for nonclassicality tests is specified. In this view, we reconsider the methods for regularizing the Glauber-Sudarshan distribution for verifying its nonclassicality. This treatment is supported with comprehensive examples and counterexamples.

  11. Robust determination of maximally localized Wannier functions

    NASA Astrophysics Data System (ADS)

    Cancès, Éric; Levitt, Antoine; Panati, Gianluca; Stoltz, Gabriel

    2017-02-01

    We propose an algorithm to determine maximally localized Wannier functions (MLWFs). This algorithm, based on recent theoretical developments, does not require any physical input such as initial guesses for the Wannier functions, unlike popular schemes based on the projection method. We discuss how the projection method can fail on fine grids when the initial guesses are too far from MLWFs. We demonstrate that our algorithm is able to find localized Wannier functions through tests on two-dimensional systems, simplified models of semiconductors, and realistic DFT systems by interfacing with the wannier90 code. We also test our algorithm on the Haldane and Kane-Mele models to examine how it fails in the presence of topological obstructions.

  12. Maximally reliable Markov chains under energy constraints.

    PubMed

    Escola, Sean; Eisele, Michael; Miller, Kenneth; Paninski, Liam

    2009-07-01

    Signal-to-noise ratios in physical systems can be significantly degraded if the outputs of the systems are highly variable. Biological processes for which highly stereotyped signal generations are necessary features appear to have reduced their signal variabilities by employing multiple processing steps. To better understand why this multistep cascade structure might be desirable, we prove that the reliability of a signal generated by a multistate system with no memory (i.e., a Markov chain) is maximal if and only if the system topology is such that the process steps irreversibly through each state, with transition rates chosen such that an equal fraction of the total signal is generated in each state. Furthermore, our result indicates that by increasing the number of states, it is possible to arbitrarily increase the reliability of the system. In a physical system, however, an energy cost is associated with maintaining irreversible transitions, and this cost increases with the number of such transitions (i.e., the number of states). Thus, an infinite-length chain, which would be perfectly reliable, is infeasible. To model the effects of energy demands on the maximally reliable solution, we numerically optimize the topology under two distinct energy functions that penalize either irreversible transitions or incommunicability between states, respectively. In both cases, the solutions are essentially irreversible linear chains, but with upper bounds on the number of states set by the amount of available energy. We therefore conclude that a physical system for which signal reliability is important should employ a linear architecture, with the number of states (and thus the reliability) determined by the intrinsic energy constraints of the system.

  13. Does Maximizing Information at the Cut Score Always Maximize Classification Accuracy and Consistency?

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Babcock, Ben

    2016-01-01

    A common suggestion made in the psychometric literature for fixed-length classification tests is that one should design tests so that they have maximum information at the cut score. Designing tests in this way is believed to maximize the classification accuracy and consistency of the assessment. This article uses simulated examples to illustrate…

  14. Anaerobic contribution during maximal anaerobic running test: correlation with maximal accumulated oxygen deficit.

    PubMed

    Zagatto, A; Redkva, P; Loures, J; Kalva Filho, C; Franco, V; Kaminagakura, E; Papoti, M

    2011-12-01

    The aims of this study were: (i) to measure energy system contributions in maximal anaerobic running test (MART); and (ii) to verify any correlation between MART and maximal accumulated oxygen deficit (MAOD). Eleven members of the armed forces were recruited for this study. Participants performed MART and MAOD, both accomplished on a treadmill. MART consisted of intermittent exercise, 20 s effort with 100 s recovery, after each spell of effort exercise. Energy system contributions by MART were also determined by excess post-exercise oxygen consumption, lactate response, and oxygen uptake measurements. MAOD was determined by five submaximal intensities and one supramaximal intensity exercises corresponding to 120% at maximal oxygen uptake intensity. Energy system contributions were 65.4±1.1% to aerobic; 29.5±1.1% to anaerobic a-lactic; and 5.1±0.5% to anaerobic lactic system throughout the whole test, while only during effort periods the anaerobic contribution corresponded to 73.5±1.0%. Maximal power found in MART corresponded to 111.25±1.33 mL/kg/min but did not significantly correlate with MAOD (4.69±0.30 L and 70.85±4.73 mL/kg). We concluded that the anaerobic a-lactic system is the main energy system in MART efforts and this test did not significantly correlate to MAOD.

  15. From entropy-maximization to equality-maximization: Gauss, Laplace, Pareto, and Subbotin

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo

    2014-12-01

    The entropy-maximization paradigm of statistical physics is well known to generate the omnipresent Gauss law. In this paper we establish an analogous socioeconomic model which maximizes social equality, rather than physical disorder, in the context of the distributions of income and wealth in human societies. We show that-on a logarithmic scale-the Laplace law is the socioeconomic equality-maximizing counterpart of the physical entropy-maximizing Gauss law, and that this law manifests an optimized balance between two opposing forces: (i) the rich and powerful, striving to amass ever more wealth, and thus to increase social inequality; and (ii) the masses, struggling to form more egalitarian societies, and thus to increase social equality. Our results lead from log-Gauss statistics to log-Laplace statistics, yield Paretian power-law tails of income and wealth distributions, and show how the emergence of a middle-class depends on the underlying levels of socioeconomic inequality and variability. Also, in the context of asset-prices with Laplace-distributed returns, our results imply that financial markets generate an optimized balance between risk and predictability.

  16. Evidence for altered alpha-adrenoreceptor responsiveness after a single bout of maximal exercise

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.

    2003-01-01

    We studied hemodynamic responses to alpha- and beta-receptor agonists in eight men to test the hypothesis that adrenoreceptor responsiveness is altered within 24 h of the performance of maximal exercise. Adrenoreceptor responsiveness was tested under two experimental conditions (with and without maximal exercise). Adrenoreceptor tests were performed 24 h after each subject performed graded upright cycle ergometry to volitional exhaustion. The 2 test days (experimental conditions) were separated by at least 1 wk, and the order of exercise and no-exercise conditions was counterbalanced. Steady-state graded infusions of phenylephrine (PE) and isoproterenol (Iso) were used to assess alpha- and beta-adrenoreceptor responsiveness, respectively. Slopes calculated from linear regressions between Iso and PE doses and changes in heart rate, blood pressure, and leg vascular resistance for each subject were used as an index of alpha- and beta-adrenoreceptor responsiveness. The slope of the relationship between heart rate and Iso with maximal exercise was 1773 +/- 164 beats x microm-1x kg-1x min-1 compared with 1987 +/- 142 beats x microg-1x kg-1x min-1 without exercise (P = 0.158), whereas the slopes of the relationship between vascular resistance to Iso were -438 +/- 123 peripheral resistance units (PRU) x microg-1x kg-1x min-1 with maximal exercise and -429 +/- 105 x microg-1x kg-1 x min-1 without exercise (P = 0.904). Maximal exercise was associated with greater (P < 0.05) vascular resistance (15.1 +/- 2.8 PRU x microg-1 kg-1x min-1) and mean arterial blood pressure (15.8 +/- 2.1 mmHg. microg-1x kg-1x min-1) responses to PE infusion compared with no exercise (9.0 +/- 2.0 PRU x microg-1 kg-1 x min-1 and 10.9 +/- 2.0 mmHg. microg-1x kg-1x min-1, respectively). These results provide evidence that a single bout of maximal exercise increases alpha1-adrenoreceptor responsiveness within 24 h without affecting beta-cardiac and vascular adrenoreceptor responses.

  17. A simplified approach to estimating the maximal lactate steady state.

    PubMed

    Snyder, A C; Woulfe, T; Welsh, R; Foster, C

    1994-01-01

    The exercise intensity associated with an elevated but stable blood lactate (HLa) concentration during constant load work (the maximal steady state, MSS) has received attention as a candidate for the "optimal" exercise intensity for endurance training. Identification of MSS ordinarily demands direct measurement of HLa or respiratory metabolism. The purpose of this study was to test the ability of heart rate (HR) to identify MSS during steady state exercise, similar to that used in conventional exercise prescription. Trained runners (n = 9) and cyclists (n = 12) performed incremental and steady state exercise. MSS was defined as the highest intensity in which blood lactate concentration increased < 1.0 mM from minutes 10 to 30. The next higher intensity workbout completed was defined as > MSS. HR models related to the presence or absence of steady state conditions were developed from the upper 95% confidence interval of MSS and the lower 95% confidence interval of > MSS. Cross validation of the model to predict MSS was performed using 21 running and 45 cycling exercise bouts in a separate group. Using the MSS upper 95% confidence interval model 84% and 76% of workbouts were correctly predicted in cyclists and runners, respectively. Using the > MSS lower 95% confidence interval model, 76% and 81% of workbouts were correctly predicted in cyclists and runners, respectively. Prediction errors tended to incorrectly predict non-steady state conditions when steady state had occurred (16/26) (62%). We conclude that use of these simple HR models may predict MSS with sufficient accuracy to be useful when direct HLa measurement is not available.

  18. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

    PubMed Central

    Arslan, Erşan; Aras, Dicle

    2016-01-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  19. Role of the autonomic nervous system in the reduced maximal cardiac output at altitude.

    PubMed

    Bogaard, Harm J; Hopkins, Susan R; Yamaya, Yoshiki; Niizeki, Kyuichi; Ziegler, Michael G; Wagner, Peter D

    2002-07-01

    After acclimatization to high altitude, maximal exercise cardiac output (QT) is reduced. Possible contributing factors include 1) blood volume depletion, 2) increased blood viscosity, 3) myocardial hypoxia, 4) altered autonomic nervous system (ANS) function affecting maximal heart rate (HR), and 5) reduced flow demand from reduced muscle work capability. We tested the role of the ANS reduction of HR in this phenomenon in five normal subjects by separately blocking the sympathetic and parasympathetic arms of the ANS during maximal exercise after 2-wk acclimatization at 3,800 m to alter maximal HR. We used intravenous doses of 8.0 mg of propranolol and 0.8 mg of glycopyrrolate, respectively. At altitude, peak HR was 170 +/- 6 beats/min, reduced from 186 +/- 3 beats/min (P = 0.012) at sea level. Propranolol further reduced peak HR to 139 +/- 2 beats/min (P = 0.001), whereas glycopyrrolate increased peak HR to sea level values, 184 +/- 3 beats/min, confirming adequate dosing with each drug. In contrast, peak O(2) consumption, work rate, and QT were similar at altitude under all drug treatments [peak QT = 16.2 +/- 1.2 (control), 15.5 +/- 1.3 (propranolol), and 16.2 +/- 1.1 l/min (glycopyrrolate)]. All QT results at altitude were lower than those at sea level (20.0 +/- 1.8 l/min in air). Therefore, this study suggests that, whereas the ANS may affect HR at altitude, peak QT is unaffected by ANS blockade. We conclude that the effect of altered ANS function on HR is not the cause of the reduced maximal QT at altitude.

  20. Effects of different levels of compression during sub-maximal and high-intensity exercise on erythrocyte deformability.

    PubMed

    Wahl, Patrick; Bloch, Wilhelm; Mester, Joachim; Born, Dennis-Peter; Sperlich, Billy

    2012-06-01

    The aim of the study was to test the hypothesis whether different levels of sock compression (0, 10, 20, and 40 mmHg) affect erythrocyte deformability and metabolic parameters during sub-maximal and maximal running. Nine well-trained, male endurance athletes (age 22.2 ± 1.3 years, peak oxygen uptake 57.7 ± 4.5 mL min(-1) kg(-1)) carried out four periods of sub-maximal running at 70% of peak oxygen uptake for 30 min followed by a ramp test until exhaustion with and without compression socks that applied different levels of pressure. Erythrocyte deformability, blood lactate, heart rate and arterial partial pressure of oxygen (pO(2)) were monitored before and during all of these tests. Erythrocyte deformability, heart rate, pO(2) and lactate concentration were unaffected by compression, whereas exercise itself significantly increased erythrocyte deformability. However, the increasing effects of exercise were attenuated when high compression was applied. This first evaluation of the potential effects of increasing levels of compression on erythrocyte deformability and metabolic parameters during (sub-) maximal exercise, revealed no effects whatsoever.

  1. Shuttle walking versus maximal cycle testing: clinical correlates in patients with kyphoscoliosis.

    PubMed

    López-Campos, José Luis; Cejudo, Pilar; Ortega, Francisco; López-Márquez, Isabel; Márquez-Martín, Eduardo; Capote, Francisco; Echevarría, Miriam; Montemayor, Teodoro; Barrot, Emilia

    2008-02-29

    A cross-sectional prospective design was used to compare the effectiveness of the shuttle walking test (SWT) and the maximal cycle ergometry test (CET) to assess the functional capacity of patients with chronic hypercapnic respiratory failure due to severe kyphoscoliosis. Twenty-four patients completed both the SWT and CET. Heart rate, blood pressure, leg fatigue, chest pain and dyspnea (Borg's scale) were measured immediately after each test. Correlation coefficients and Bland-Altman analysis were used to compare the two methods. Borg's dyspnea, leg and chest pain after exercise were not significantly different between tests. Only heart rate (SWT 130[20.7] versus CET 116[28.75]; p = 0.048) and diastolic blood pressure (SWT: 85.5[13.75] versus CET 95[17.5]; p = 0.021) were slightly but significantly different between the two protocols. There was a good positive correlation between the distance walked in SWT and maximal oxygen consumption (r = 0.675; p < 0.001). SWT and CET testing elicited similar clinical and hemodynamic responses. SWT is a feasible measure of functional capacity in this patient group.

  2. Exercise and heart failure in the elderly.

    PubMed

    Kappagoda, Tissa; Amsterdam, Ezra A

    2012-09-01

    In this review, we will examine the physiological responses to exercise in elderly populations (age > 65 years) with and without evidence of heart failure. Aging per se in both men and women is associated with a ~40% lower maximum oxygen consumption in sedentary subjects. In trained individuals, this value is 25-32% lower. A smaller SV accounts for nearly 50% of these age-related differences, and the remainder is explained by a lower maximal HR and reduced oxygen extraction. Exercise training is also associated with an increase in the arteriovenous O(2) difference in previously sedentary elderly men and women, which probably contributes to the overall beneficial effect of training in the elderly. However, during vigorous exercise (125 W), the cardiac output in the elderly is dependent upon an age-related increase in end-diastolic volume and stroke volume, which "compensates" partially for the age-related decrease in heart rate. Hence, in elderly individuals, the stroke volume during exercise depends upon diastolic filling. The changes that occur in the heart are also associated with an overall reduction in efferent sympathetic nerve activity. Despite this decline, the metaboreflex initiated by receptors in exercising muscles remains the main determinant of sympathetic activation (to maintain blood pressure) during exercise in the elderly. It is recognized that aging is associated with the development of heart failure, particularly in women in whom its prevalence increases >twofold from age 65-69 (6.6%) to age 85 years (14%). Almost half the people presenting with heart failure appear to have normal left ventricular systolic function, a phenomenon that is more common in women. Exercise training in elderly people with and without heart failure appears to have a beneficial effect in terms of enhancing the quality of life and functional capacity. Mortality benefit in the latter has not been established with certainty.

  3. Maximal and sub-maximal functional lifting performance at different platform heights.

    PubMed

    Savage, Robert J; Jaffrey, Mark A; Billing, Daniel C; Ham, Daniel J

    2015-01-01

    Introducing valid physical employment tests requires identifying and developing a small number of practical tests that provide broad coverage of physical performance across the full range of job tasks. This study investigated discrete lifting performance across various platform heights reflective of common military lifting tasks. Sixteen Australian Army personnel performed a discrete lifting assessment to maximal lifting capacity (MLC) and maximal acceptable weight of lift (MAWL) at four platform heights between 1.30 and 1.70 m. There were strong correlations between platform height and normalised lifting performance for MLC (R(2) = 0.76 ± 0.18, p < 0.05) and MAWL (R(2) = 0.73 ± 0.21, p < 0.05). The developed relationship allowed prediction of lifting capacity at one platform height based on lifting capacity at any of the three other heights, with a standard error of < 4.5 kg and < 2.0 kg for MLC and MAWL, respectively.

  4. Maximally Expressive Modeling of Operations Tasks

    NASA Technical Reports Server (NTRS)

    Jaap, John; Richardson, Lea; Davis, Elizabeth

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed, the information sought is at the cutting edge of scientific endeavor, and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a "maximally expressive" modeling schema.

  5. Maximizing exosome colloidal stability following electroporation.

    PubMed

    Hood, Joshua L; Scott, Michael J; Wickline, Samuel A

    2014-03-01

    Development of exosome-based semisynthetic nanovesicles for diagnostic and therapeutic purposes requires novel approaches to load exosomes with cargo. Electroporation has previously been used to load exosomes with RNA. However, investigations into exosome colloidal stability following electroporation have not been considered. Herein, we report the development of a unique trehalose pulse media (TPM) that minimizes exosome aggregation following electroporation. Dynamic light scattering (DLS) and RNA absorbance were employed to determine the extent of exosome aggregation and electroextraction post electroporation in TPM compared to common PBS pulse media or sucrose pulse media (SPM). Use of TPM to disaggregate melanoma exosomes post electroporation was dependent on both exosome concentration and electric field strength. TPM maximized exosome dispersal post electroporation for both homogenous B16 melanoma and heterogeneous human serum-derived populations of exosomes. Moreover, TPM enabled heavy cargo loading of melanoma exosomes with 5nm superparamagnetic iron oxide nanoparticles (SPION5) while maintaining original exosome size and minimizing exosome aggregation as evidenced by transmission electron microscopy. Loading exosomes with SPION5 increased exosome density on sucrose gradients. This provides a simple, label-free means of enriching exogenously modified exosomes and introduces the potential for MRI-driven theranostic exosome investigations in vivo.

  6. Maximal respiratory pressure in healthy Japanese children.

    PubMed

    Tagami, Miki; Okuno, Yukako; Matsuda, Tadamitsu; Kawamura, Kenta; Shoji, Ryosuke; Tomita, Kazuhide

    2017-03-01

    [Purpose] Normal values for respiratory muscle pressures during development in Japanese children have not been reported. The purpose of this study was to investigate respiratory muscle pressures in Japanese children aged 3-12 years. [Subjects and Methods] We measured respiratory muscle pressure values using a manovacuometer without a nose clip, with subjects in a sitting position. Data were collected for ages 3-6 (Group I: 68 subjects), 7-9 (Group II: 86 subjects), and 10-12 (Group III: 64 subjects) years. [Results] The values for respiratory muscle pressures in children were significantly higher with age in both sexes, and were higher in boys than in girls. Correlation coefficients were significant at values of 0.279 to 0.471 for each gender relationship between maximal respiratory pressure and age, height, and weight, respectively. [Conclusion] In this study, we showed pediatric respiratory muscle pressure reference value for each age. In the present study, values for respiratory muscle pressures were lower than Brazilian studies. This suggests that differences in respiratory muscle pressures vary with ethnicity.

  7. Maximally localized Wannier functions: Theory and applications

    NASA Astrophysics Data System (ADS)

    Marzari, Nicola; Mostofi, Arash A.; Yates, Jonathan R.; Souza, Ivo; Vanderbilt, David

    2012-10-01

    The electronic ground state of a periodic system is usually described in terms of extended Bloch orbitals, but an alternative representation in terms of localized “Wannier functions” was introduced by Gregory Wannier in 1937. The connection between the Bloch and Wannier representations is realized by families of transformations in a continuous space of unitary matrices, carrying a large degree of arbitrariness. Since 1997, methods have been developed that allow one to iteratively transform the extended Bloch orbitals of a first-principles calculation into a unique set of maximally localized Wannier functions, accomplishing the solid-state equivalent of constructing localized molecular orbitals, or “Boys orbitals” as previously known from the chemistry literature. These developments are reviewed here, and a survey of the applications of these methods is presented. This latter includes a description of their use in analyzing the nature of chemical bonding, or as a local probe of phenomena related to electric polarization and orbital magnetization. Wannier interpolation schemes are also reviewed, by which quantities computed on a coarse reciprocal-space mesh can be used to interpolate onto much finer meshes at low cost, and applications in which Wannier functions are used as efficient basis functions are discussed. Finally the construction and use of Wannier functions outside the context of electronic-structure theory is presented, for cases that include phonon excitations, photonic crystals, and cold-atom optical lattices.

  8. Inverting Monotonic Nonlinearities by Entropy Maximization

    PubMed Central

    López-de-Ipiña Pena, Karmele; Caiafa, Cesar F.

    2016-01-01

    This paper proposes a new method for blind inversion of a monotonic nonlinear map applied to a sum of random variables. Such kinds of mixtures of random variables are found in source separation and Wiener system inversion problems, for example. The importance of our proposed method is based on the fact that it permits to decouple the estimation of the nonlinear part (nonlinear compensation) from the estimation of the linear one (source separation matrix or deconvolution filter), which can be solved by applying any convenient linear algorithm. Our new nonlinear compensation algorithm, the MaxEnt algorithm, generalizes the idea of Gaussianization of the observation by maximizing its entropy instead. We developed two versions of our algorithm based either in a polynomial or a neural network parameterization of the nonlinear function. We provide a sufficient condition on the nonlinear function and the probability distribution that gives a guarantee for the MaxEnt method to succeed compensating the distortion. Through an extensive set of simulations, MaxEnt is compared with existing algorithms for blind approximation of nonlinear maps. Experiments show that MaxEnt is able to successfully compensate monotonic distortions outperforming other methods in terms of the obtained Signal to Noise Ratio in many important cases, for example when the number of variables in a mixture is small. Besides its ability for compensating nonlinearities, MaxEnt is very robust, i.e. showing small variability in the results. PMID:27780261

  9. Viral quasispecies assembly via maximal clique enumeration.

    PubMed

    Töpfer, Armin; Marschall, Tobias; Bull, Rowena A; Luciani, Fabio; Schönhuth, Alexander; Beerenwinkel, Niko

    2014-03-01

    Virus populations can display high genetic diversity within individual hosts. The intra-host collection of viral haplotypes, called viral quasispecies, is an important determinant of virulence, pathogenesis, and treatment outcome. We present HaploClique, a computational approach to reconstruct the structure of a viral quasispecies from next-generation sequencing data as obtained from bulk sequencing of mixed virus samples. We develop a statistical model for paired-end reads accounting for mutations, insertions, and deletions. Using an iterative maximal clique enumeration approach, read pairs are assembled into haplotypes of increasing length, eventually enabling global haplotype assembly. The performance of our quasispecies assembly method is assessed on simulated data for varying population characteristics and sequencing technology parameters. Owing to its paired-end handling, HaploClique compares favorably to state-of-the-art haplotype inference methods. It can reconstruct error-free full-length haplotypes from low coverage samples and detect large insertions and deletions at low frequencies. We applied HaploClique to sequencing data derived from a clinical hepatitis C virus population of an infected patient and discovered a novel deletion of length 357±167 bp that was validated by two independent long-read sequencing experiments. HaploClique is available at https://github.com/armintoepfer/haploclique. A summary of this paper appears in the proceedings of the RECOMB 2014 conference, April 2-5.

  10. Network channel allocation and revenue maximization

    NASA Astrophysics Data System (ADS)

    Hamalainen, Timo; Joutsensalo, Jyrki

    2002-09-01

    This paper introduces a model that can be used to share link capacity among customers under different kind of traffic conditions. This model is suitable for different kind of networks like the 4G networks (fast wireless access to wired network) to support connections of given duration that requires a certain quality of service. We study different types of network traffic mixed in a same communication link. A single link is considered as a bottleneck and the goal is to find customer traffic profiles that maximizes the revenue of the link. Presented allocation system accepts every calls and there is not absolute blocking, but the offered data rate/user depends on the network load. Data arrival rate depends on the current link utilization, user's payment (selected CoS class) and delay. The arrival rate is (i) increasing with respect to the offered data rate, (ii) decreasing with respect to the price, (iii) decreasing with respect to the network load, and (iv) decreasing with respect to the delay. As an example, explicit formula obeying these conditions is given and analyzed.

  11. Evolution of correlated multiplexity through stability maximization

    NASA Astrophysics Data System (ADS)

    Dwivedi, Sanjiv K.; Jalan, Sarika

    2017-02-01

    Investigating the relation between various structural patterns found in real-world networks and the stability of underlying systems is crucial to understand the importance and evolutionary origin of such patterns. We evolve multiplex networks, comprising antisymmetric couplings in one layer depicting predator-prey relationship and symmetric couplings in the other depicting mutualistic (or competitive) relationship, based on stability maximization through the largest eigenvalue of the corresponding adjacency matrices. We find that there is an emergence of the correlated multiplexity between the mirror nodes as the evolution progresses. Importantly, evolved values of the correlated multiplexity exhibit a dependence on the interlayer coupling strength. Additionally, the interlayer coupling strength governs the evolution of the disassortativity property in the individual layers. We provide analytical understanding to these findings by considering starlike networks representing both the layers. The framework discussed here is useful for understanding principles governing the stability as well as the importance of various patterns in the underlying networks of real-world systems ranging from the brain to ecology which consist of multiple types of interaction behavior.

  12. Maximizing Exosome Colloidal Stability Following Electroporation

    PubMed Central

    Hood, Joshua L.; Scott, Michael J.; Wickline, Samuel A.

    2014-01-01

    Development of exosome based semi-synthetic nanovesicles for diagnostic and therapeutic purposes requires novel approaches to load exosomes with cargo. Electroporation has previously been used to load exosomes with RNA. However, investigations into exosome colloidal stability following electroporation have not been considered. Herein, we report the development of a unique trehalose pulse media (TPM) that minimizes exosome aggregation following electroporation. Dynamic light scattering (DLS) and RNA absorbance were employed to determine the extent of exosome aggregation and electroextraction post electroporation in TPM compared to common PBS pulse media or sucrose pulse media (SPM). Use of TPM to disaggregate melanoma exosomes post electroporation was dependent on both exosome concentration and electric field strength. TPM maximized exosome dispersal post electroporation for both homogenous B16 melanoma and heterogeneous human serum derived populations of exosomes. Moreover, TPM enabled heavy cargo loading of melanoma exosomes with 5 nm superparamagnetic iron oxide nanoparticles (SPION5) while maintaining original exosome size and minimizing exosome aggregation as evidenced by transmission electron microscopy. Loading exosomes with SPION5 increased exosome density on sucrose gradients. This provides a simple, label free means to enrich exogenously modified exosomes and introduces the potential for MRI driven theranostic exosome investigations in vivo. PMID:24333249

  13. Predicting maximal grip strength using hand circumference.

    PubMed

    Li, Ke; Hewson, David J; Duchêne, Jacques; Hogrel, Jean-Yves

    2010-12-01

    The objective of this study was to analyze the correlations between anthropometric data and maximal grip strength (MGS) in order to establish a simple model to predict "normal" MGS. Randomized bilateral measurement of MGS was performed on a homogeneous population of 100 subjects. MGS was measured according to a standardized protocol with three dynamometers (Jamar, Myogrip and Martin Vigorimeter) for both dominant and non-dominant sides. Several anthropometric data were also measured: height; weight; hand, wrist and forearm circumference; hand and palm length. Among these data, hand circumference had the strongest correlation with MGS for all three dynamometers and for both hands (0.789 and 0.782 for Jamar; 0.829 and 0.824 for Myogrip; 0.663 and 0.730 for Vigorimeter). In addition, the only anthropometric variable systematically selected by a stepwise multiple linear regression analysis was also hand circumference. Based on this parameter alone, a predictive regression model presented good results (r(2) = 0.624 for Jamar; r(2) = 0.683 for Myogrip and r(2) = 0.473 for Vigorimeter; all adjusted r(2)). Moreover a single equation was predictive of MGS for both men and women and for both non-dominant and dominant hands. "Normal" MGS can be predicted using hand circumference alone.

  14. Maximal respiratory pressure in healthy Japanese children

    PubMed Central

    Tagami, Miki; Okuno, Yukako; Matsuda, Tadamitsu; Kawamura, Kenta; Shoji, Ryosuke; Tomita, Kazuhide

    2017-01-01

    [Purpose] Normal values for respiratory muscle pressures during development in Japanese children have not been reported. The purpose of this study was to investigate respiratory muscle pressures in Japanese children aged 3–12 years. [Subjects and Methods] We measured respiratory muscle pressure values using a manovacuometer without a nose clip, with subjects in a sitting position. Data were collected for ages 3–6 (Group I: 68 subjects), 7–9 (Group II: 86 subjects), and 10–12 (Group III: 64 subjects) years. [Results] The values for respiratory muscle pressures in children were significantly higher with age in both sexes, and were higher in boys than in girls. Correlation coefficients were significant at values of 0.279 to 0.471 for each gender relationship between maximal respiratory pressure and age, height, and weight, respectively. [Conclusion] In this study, we showed pediatric respiratory muscle pressure reference value for each age. In the present study, values for respiratory muscle pressures were lower than Brazilian studies. This suggests that differences in respiratory muscle pressures vary with ethnicity. PMID:28356644

  15. Reflection quasilattices and the maximal quasilattice

    NASA Astrophysics Data System (ADS)

    Boyle, Latham; Steinhardt, Paul J.

    2016-08-01

    We introduce the concept of a reflection quasilattice, the quasiperiodic generalization of a Bravais lattice with irreducible reflection symmetry. Among their applications, reflection quasilattices are the reciprocal (i.e., Bragg diffraction) lattices for quasicrystals and quasicrystal tilings, such as Penrose tilings, with irreducible reflection symmetry and discrete scale invariance. In a follow-up paper, we will show that reflection quasilattices can be used to generate tilings in real space with properties analogous to those in Penrose tilings, but with different symmetries and in various dimensions. Here we explain that reflection quasilattices only exist in dimensions two, three, and four, and we prove that there is a unique reflection quasilattice in dimension four: the "maximal reflection quasilattice" in terms of dimensionality and symmetry. Unlike crystallographic Bravais lattices, all reflection quasilattices are invariant under rescaling by certain discrete scale factors. We tabulate the complete set of scale factors for all reflection quasilattices in dimension d >2 , and for all those with quadratic irrational scale factors in d =2 .

  16. Heart transplantation: review

    PubMed Central

    Mangini, Sandrigo; Alves, Bárbara Rubim; Silvestre, Odílson Marcos; Pires, Philippe Vieira; Pires, Lucas José Tachotti; Curiati, Milena Novaes Cardoso; Bacal, Fernando

    2015-01-01

    ABSTRACT Heart transplantation is currently the definitive gold standard surgical approach in the treatment of refractory heart failure. However, the shortage of donors limits the achievement of a greater number of heart transplants, in which the use of mechanical circulatory support devices is increasing. With well-established indications and contraindications, as well as diagnosis and treatment of rejection through defined protocols of immunosuppression, the outcomes of heart transplantation are very favorable. Among early complications that can impact survival are primary graft failure, right ventricular dysfunction, rejection, and infections, whereas late complications include cardiac allograft vasculopathy and neoplasms. Despite the difficulties for heart transplantation, in particular, the shortage of donors and high mortality while on the waiting list, in Brazil, there is a great potential for both increasing effective donors and using circulatory assist devices, which can positively impact the number and outcomes of heart transplants. PMID:26154552

  17. Isometric exercise in the denervated heart: a Doppler echocardiographic study.

    PubMed Central

    Robson, S C; Furniss, S S; Heads, A; Boys, R J; McGregor, C; Bexton, R S

    1989-01-01

    The haemodynamic responses to isometric exercise of eight recipients of orthotopic heart transplants and eight healthy controls were studied. Each performed sustained exercise at 30% of maximal voluntary contraction for three minutes on a handgrip dynamometer. Cardiac output was measured by combined Doppler and cross sectional echocardiography before exercise and every 30 seconds during and after exercise. In the controls cardiac output and blood pressure increased significantly owing to an increase in heart rate with no change in stroke volume. In the transplant group cardiac output, heart rate, and stroke volume remained unchanged throughout exercise. In contrast with its response to dynamic exercise the denervated human heart is unable to increase cardiac output during isometric exercise. The pressor response that occurs is mediated via an increase in peripheral vascular resistance. PMID:2649119

  18. Swan-Ganz - right heart catheterization

    MedlinePlus

    ... Congenital heart disease Heart failure Kidney disease Leaky heart valves (valvular regurgitation) Shock It may also be done ... flow problems, such as heart failure or shock Heart valve disease Lung disease Structural problems with the heart, ...

  19. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  20. Texas Heart Institute

    MedlinePlus

    ... Texas Heart Institute, The University of Texas Health Science Center at Houston, MD Anderson Cancer Center, and The University of Houston. Held most ... for Physicians Fellowships & Residencies School ...

  1. Rare flavor processes in Maximally Natural Supersymmetry

    NASA Astrophysics Data System (ADS)

    García, Isabel García; March-Russell, John

    2015-01-01

    We study CP-conserving rare flavor violating processes in the recently proposed theory of Maximally Natural Supersymmetry (MNSUSY). MNSUSY is an unusual supersymmetric (SUSY) extension of the Standard Model (SM) which, remarkably, is untuned at present LHC limits. It employs Scherk-Schwarz breaking of SUSY by boundary conditions upon compactifying an underlying 5-dimensional (5D) theory down to 4D, and is not well-described by softly-broken SUSY, with much different phenomenology than the Minimal Supersymmetric Standard Model (MSSM) and its variants. The usual CP-conserving SUSY-flavor problem is automatically solved in MNSUSY due to a residual almost exact U(1) R symmetry, naturally heavy and highly degenerate 1st- and 2nd-generation sfermions, and heavy gauginos and Higgsinos. Depending on the exact implementation of MNSUSY there exist important new sources of flavor violation involving gauge boson Kaluza-Klein (KK) excitations. The spatial localization properties of the matter multiplets, in particular the brane localization of the 3rd generation states, imply KK-parity is broken and tree-level contributions to flavor changing neutral currents are present in general. Nevertheless, we show that simple variants of the basic MNSUSY model are safe from present flavor constraints arising from kaon and B-meson oscillations, the rare decays B s, d → μ + μ -, μ → ēee and μ- e conversion in nuclei. We also briefly discuss some special features of the radiative decays μ → eγ and . Future experiments, especially those concerned with lepton flavor violation, should see deviations from SM predictions unless one of the MNSUSY variants with enhanced flavor symmetries is realized.

  2. Nuts and Your Heart: Eating Nuts for Heart Health

    MedlinePlus

    Diseases and Conditions Heart disease Eating nuts helps your heart. Discover how walnuts, almonds and other nuts can help lower your cholesterol when ... a healthy diet may be good for your heart. Nuts contain unsaturated fatty acids and other nutrients. ...

  3. Dimensional analysis of heart rate variability in heart transplant recipients

    SciTech Connect

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  4. Maximality-Based Structural Operational Semantics for Petri Nets

    NASA Astrophysics Data System (ADS)

    Saīdouni, Djamel Eddine; Belala, Nabil; Bouneb, Messaouda

    2009-03-01

    The goal of this work is to exploit an implementable model, namely the maximality-based labeled transition system, which permits to express true-concurrency in a natural way without splitting actions on their start and end events. One can do this by giving a maximality-based structural operational semantics for the model of Place/Transition Petri nets in terms of maximality-based labeled transition systems structures.

  5. Women's Heart Foundation

    MedlinePlus

    ... by Dr. Stephen Sinatra - "Should I take a Statin?" - TED TALK by Dr. Noel Bairey Merz - discusses new heart diagnostics for women - TED TALK by Dr. Joel Furhman - discusses how to eat to prevent and reverse heart disease - Women get their own stroke guidelines - AHA - Speak ...

  6. Mapping the Heart

    ERIC Educational Resources Information Center

    Hulse, Grace

    2012-01-01

    In this article, the author describes how her fourth graders made ceramic heart maps. The impetus for this project came from reading "My Map Book" by Sara Fanelli. This book is a collection of quirky, hand-drawn and collaged maps that diagram a child's world. There are maps of her stomach, her day, her family, and her heart, among others. The…

  7. Heart imaging method

    DOEpatents

    Collins, H. Dale; Gribble, R. Parks; Busse, Lawrence J.

    1991-01-01

    A method for providing an image of the human heart's electrical system derives time-of-flight data from an array of EKG electrodes and this data is transformed into phase information. The phase information, treated as a hologram, is reconstructed to provide an image in one or two dimensions of the electrical system of the functioning heart.

  8. Target Heart Rates

    MedlinePlus

    ... Terms and Conditions and Privacy Policy Lower Your Sodium in 21 Days! Learn how you can lower your sodium and change your salty ways in 21 Days! Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Target Heart Rates 4 Heart ...

  9. Anxiety and Heart Disease

    DTIC Science & Technology

    2003-01-01

    disability among women and men in the United States. By the year 2020, CHD is projected to be the number one cause of death worldwide.( American Heart Association , 2002...combined.( American Heart Association , 2002) The effect of various demographic (e.g., age, gender) and clinical (e.g., presence of comorbidities

  10. The total artificial heart.

    PubMed

    Cook, Jason A; Shah, Keyur B; Quader, Mohammed A; Cooke, Richard H; Kasirajan, Vigneshwar; Rao, Kris K; Smallfield, Melissa C; Tchoukina, Inna; Tang, Daniel G

    2015-12-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review.

  11. The total artificial heart

    PubMed Central

    Cook, Jason A.; Shah, Keyur B.; Quader, Mohammed A.; Cooke, Richard H.; Kasirajan, Vigneshwar; Rao, Kris K.; Smallfield, Melissa C.; Tchoukina, Inna

    2015-01-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

  12. Diabetic Heart Disease

    MedlinePlus

    ... cardiomyopathy (KAR-de-o-mi-OP-ah-thee). Coronary Heart Disease In CHD, a waxy substance called plaque (plak) ... DHD tend to have less success with some heart disease treatments, such as coronary artery bypass grafting and percutaneous coronary intervention , also ...

  13. Human heart by art.

    PubMed

    Tamir, Abraham

    2012-11-01

    Heart is of great importance in maintaining the life of the body. Enough to stop working for a few minutes to cause death, and hence the great importance in physiology, medicine, and research. This fact was already emphasized in the Bible in the Book of Proverbs, chapter 4 verse 23: "Keep your heart with all diligence, for out of it is the wellspring of life." Art was able to demonstrate the heart from various aspects; realistically, as done by Leonardo de Vinci who demonstrated the halves of the heart and its blood vessels. Symbolically, as a source of life, the heart was demonstrated by the artist Mrs. Erlondeiel, as a caricature by Salvador Dali, as an open heart by Sawaya, etc. Finally, it should be emphasized that different demonstrations of the human heart by many artworks make this most important organ of our body (that cannot be seen from outside) more familiar and clearer to us. And this is the purpose of this article-to demonstrate the heart through a large number of artworks of different kinds.

  14. Music and the heart.

    PubMed

    Koelsch, Stefan; Jäncke, Lutz

    2015-11-21

    Music can powerfully evoke and modulate emotions and moods, along with changes in heart activity, blood pressure (BP), and breathing. Although there is great heterogeneity in methods and quality among previous studies on effects of music on the heart, the following findings emerge from the literature: Heart rate (HR) and respiratory rate (RR) are higher in response to exciting music compared with tranquilizing music. During musical frissons (involving shivers and piloerection), both HR and RR increase. Moreover, HR and RR tend to increase in response to music compared with silence, and HR appears to decrease in response to unpleasant music compared with pleasant music. We found no studies that would provide evidence for entrainment of HR to musical beats. Corresponding to the increase in HR, listening to exciting music (compared with tranquilizing music) is associated with a reduction of heart rate variability (HRV), including reductions of both low-frequency and high-frequency power of the HRV. Recent findings also suggest effects of music-evoked emotions on regional activity of the heart, as reflected in electrocardiogram amplitude patterns. In patients with heart disease (similar to other patient groups), music can reduce pain and anxiety, associated with lower HR and lower BP. In general, effects of music on the heart are small, and there is great inhomogeneity among studies with regard to methods, findings, and quality. Therefore, there is urgent need for systematic high-quality research on the effects of music on the heart, and on the beneficial effects of music in clinical settings.

  15. Morphogenesis of univentricular hearts.

    PubMed Central

    Anderson, R H; Becker, A E; Wilkinson, J L; Gerlis, L M

    1976-01-01

    Two main theories exist for the explanation of univentricular hearts. One states that the bulboventricular septum becomes realigned to form the interventricular septum, and that univentricular hearts are a consequence of failure of this realignment. The other states that bulboventricular and interventricular septa are different structures, and that the univentricular heart results from failure of formation of the posterior interventricular septum. Four hearts are described in which both the posterior septum and an anterior bulboventricular septum are present. In each heart, therefore, the right ventricular sinus is separated both from the left ventricular sinus and from a discrete outlet chamber which supports the pulmonary artery. It is argued that these findings militate strongly against theories proposing reorientation of the bulboventricular septum to form the definitive interventricular septum. They support strongly the concept that the definitive right ventricle is formed in part from the bulbus and in part from the primitive ventricle. On the basis of these findings, it is suggested that the distinctive feature of the univentricular heart is absence of the posterior septum. Such hearts can properly be termed 'primitive ventricle'. It is also suggested that hearts with atretic or straddling valves should be included within this category. Images PMID:1275986

  16. Cyanotic heart disease

    MedlinePlus

    ... the body and flows through the heart and lungs. Blood that is low in oxygen (blue blood) returns ... the way blood flows through the heart and lungs. This causes non-oxygenated blood to be pumped out to the body without ...

  17. Patterns of Heart Attacks

    DTIC Science & Technology

    2010-06-01

    36 5.1 Pattern of gradually increasing occurrence of COPD .............................................. 37 5.2 Pattern of...deaths [1]. According to the Heart Disease and Stroke Statistics - 2010 Update from the American Heart Association, the estimated annual incidence of MI...7]. The study combined the insurance claims from the Medicare and the Manitoba Health Services Commission claims database with hospitalization

  18. Acute Decompensated Heart Failure

    PubMed Central

    Joseph, Susan M.; Cedars, Ari M.; Ewald, Gregory A.; Geltman, Edward M.; Mann, Douglas L.

    2009-01-01

    Hospitalizations for acute decompensated heart failure are increasing in the United States. Moreover, the prevalence of heart failure is increasing consequent to an increased number of older individuals, as well as to improvement in therapies for coronary artery disease and sudden cardiac death that have enabled patients to live longer with cardiovascular disease. The main treatment goals in the hospitalized patient with heart failure are to restore euvolemia and to minimize adverse events. Common in-hospital treatments include intravenous diuretics, vasodilators, and inotropic agents. Novel pharmaceutical agents have shown promise in the treatment of acute decompensated heart failure and may simplify the treatment and reduce the morbidity associated with the disease. This review summarizes the contemporary management of patients with acute decompensated heart failure. PMID:20069075

  19. Living with Diabetic Heart Disease

    MedlinePlus

    ... from the NHLBI on Twitter. Living With Diabetic Heart Disease Diabetic heart disease (DHD) increases the likelihood of earlier and more ... also tend to have less success from certain heart disease treatments, such as coronary artery bypass grafting and ...

  20. Guidelines for Better Heart Health

    MedlinePlus

    ... Home Current Issue Past Issues Guidelines for Better Heart Health Past Issues / Winter 2007 Table of Contents For ... Heart Association (AHA) released new guidelines for preventing heart disease and stroke ... health. Those guidelines, still in effect today, adopted the ...

  1. What Causes Heart Valve Disease?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Heart Valve Disease? Heart conditions and other disorders, age-related changes, ... valve disease. Other Conditions and Factors Linked to Heart Valve Disease Many other conditions and factors are linked to ...

  2. Signs of a Heart Attack

    MedlinePlus

    ... attack Heart Health and Stroke Signs of a heart attack Related information Make the Call. Don't Miss ... to top More information on Signs of a heart attack Read more from womenshealth.gov Make the Call, ...

  3. What Are Congenital Heart Defects?

    MedlinePlus

    ... heart disease. Google+ Hangout on the first large-scale gene sequencing analysis of congenital heart disease 05/ ... in the journal Nature, about the first large-scale sequencing analysis of congenital heart disease. This NHLBI- ...

  4. Types of Congenital Heart Defects

    MedlinePlus

    ... heart disease. Google+ Hangout on the first large-scale gene sequencing analysis of congenital heart disease 05/ ... in the journal Nature, about the first large-scale sequencing analysis of congenital heart disease. This NHLBI- ...

  5. Preparing Children for Heart Surgery

    MedlinePlus

    ... Physical Activity Recommendations for Heart Health • Tools & Resources Web Booklets on Congenital Heart Defects These online publications ... to you or your child’s defect and concerns. Web Booklet: Adults With Congenital Heart Defects Web Booklet: ...

  6. EPA Heathy Heart Program Webinar

    EPA Pesticide Factsheets

    EPA is raising awareness of heart disease and its link to air pollution and other environmental factors as a partner in the Million Hearts, a national initiative to prevent 1 million heart attacks and strokes by 2017.

  7. Substances and Heart Rhythm Disorders

    MedlinePlus

    ... that trigger the heartbeat. Caffeine, Diet and Heart Arrhythmias Caffeine is the most common substance linked with abnormal heart rhythms ( arrhythmias ). Some people feel heart palpitations (fast heartbeats) when ...

  8. Data and Statistics: Heart Failure

    MedlinePlus

    ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... to Prevent and Control Chronic Diseases Million Hearts® Web Sites with More Information About Heart Failure For ...

  9. Illegal Drugs and Heart Disease

    MedlinePlus

    ... vessels and heart valves. Many drugs, such as cocaine, heroin and various forms of amphetamine, affect the ... heart attacks, seizures, and respiratory arrest More about Cocaine - the "perfect heart-attack drug" The powdered form ...

  10. [Heart disease or sick at heart].

    PubMed

    Nager, F

    1993-02-27

    It is attempted to draw attention to the demanding and complementary reality of the modern cardiologist by confronting cardiology and cordiology (symbolistic theory of the heart). After a short survey of the symbolic and mythological world of the heart, the question of compatibility between the apparently opposing poles of cardiologic curative technology and cordiologic emotionalism is posed. With respect to the comprehensive cardiology of tomorrow, it is crucial whether the modern cardiac specialist will be capable of a difficult quadruple synthesis, namely: (1) the harmonious interaction between a rational basic position (raison de la mathématique) and an irrational-emotional standpoint (raison du coeur), (2) the increasing closeness of science and humanity, (3) the balanced care and culture of technology and medical language, and (4) the increasing harmony of male and female norms. Future cardiology must follow the call of the complementary, which reflects the apparent contrast between the scientific and the poetic heart; between having a symbolic heart condition and being heartsick.

  11. Profound spatial heterogeneity of coronary reserve. Discordance between patterns of resting and maximal myocardial blood flow.

    PubMed

    Austin, R E; Aldea, G S; Coggins, D L; Flynn, A E; Hoffman, J I

    1990-08-01

    We examined the ability of individual regions of the canine left ventricle to increase blood flow relative to baseline rates of perfusion. Regional coronary flow was measured by injecting radioactive microspheres over 90 seconds in seven anesthetized mongrel dogs. Preliminary experiments demonstrated a correlation between the regional distributions of blood flow during asphyxia and pharmacological vasodilatation with adenosine (mean r = 0.75; 192 regions in each of two dogs), both of which resulted in increased coronary flow. Subsequent experiments, during which coronary perfusion pressure was held constant at 80 mm Hg, examined the pattern of blood flow in 384 regions (mean weight, 106 mg) of the left ventricular free wall during resting flow and during maximal coronary flow effected by intracoronary adenosine infusion. We found that resting and maximal flow patterns were completely uncorrelated to each other in a given dog (mean r = 0.06, p = NS; n = 3 dogs). Furthermore, regional coronary reserve, defined as the ratio of maximal to resting flow, ranged from 1.75 (i.e., resting flow was 57% of maximum) to 21.9 (resting flow was 4.5% of maximum). Thus, coronary reserve is spatially heterogeneous and determined by two distinct perfusion patterns: the resting (control) pattern and the maximal perfusion pattern. Normal hearts, therefore, contain small regions that may be relatively more vulnerable to ischemia. This may explain the patchy nature of infarction with hypoxia and at reduced perfusion pressures as well as the difficulty of using global parameters to predict regional ischemia. Despite the wide dispersion of coronary reserve, we found, by autocorrelation analysis, that reserve in neighboring regions (even when separated by a distance of several tissue samples) was significantly correlated. This also applied to patterns of resting myocardial flow. Thus, both resting coronary blood flow and reserve appear to be locally continuous and may define functional

  12. Cardiorespiratory responses to maximal arm and leg exercise in national-class marathon runners.

    PubMed

    deJong, Adam T; Bonzheim, Kimberly; Franklin, Barry A; Saltarelli, William

    2009-06-01

    Marathon runners (MR) are among the most aerobically fit athletes in the world. Although aerobic capacity (VO(2)max) during arm exercise generally varies between 64% and 80% of leg VO(2)max (mean 70%) in healthy men, few data are available regarding the comparative arm fitness of MR. To clarify the relationship between arm and leg fitness in MR, we studied 10 national-class MR (mean + or - standard deviation age 30 + or - 4 years) whose best marathon times averaged < 2 hours and 40 minutes. Each MR underwent lower and upper body maximal exercise evaluations with measurement of cardiorespiratory variables using indirect calorimetry during treadmill testing (standard Bruce protocol) and arm-crank ergometry, respectively. Our subjects achieved VO(2)max levels equaling 75.8 + or - 7.1 mL/kg/min (5.2 + or - 0.6 L/min) during treadmill testing, which was significantly higher than the level of cardiorespiratory fitness achieved during maximal arm exercise (45.4 + or - 12.4 mL/kg/min [3.1 + or - 0.9 L/min]; P < 0.01). In addition, maximal heart rate (183.2 + or - 8.2 vs 163.7 + or - 10 bpm) and systolic blood pressure (201.8 + or - 10.1 vs 186.6 + or - 12.1 mm Hg) were significantly higher (P < 0.01 and P < 0.05, respectively) during maximal leg versus arm exercise. Relative arm fitness (arm VO(2)max/leg VO(2)max) was extremely variable (41%-76%), averaging 60% + or - 13%. Although MR are able to achieve significantly higher VO(2)max values during treadmill testing than those observed in the general population, their relative arm fitness appears to be slightly reduced. These findings add to and strongly support the specificity of measurement and training concept.

  13. Heart rates of elementary physical education students during the dancing classrooms program.

    PubMed

    Nelson, Larry; Evans, Melissa; Guess, Wendy; Morris, Mary; Olson, Terry; Buckwalter, John

    2011-06-01

    We examined how different types of dance activities, along with their duration, influenced heart rate responses among fifth-grade physical education students (N = 96) who participated in the Dancing Classrooms program. Results indicated that the overall Dancing Classrooms program elicits a moderate cardiovascular heart rate response (M = 124.4 bpm), in which 47% of class time was spent above a 60% maximal heart rate threshold. The swing dance in particular (M = 143.4 bpm) stimulated a much higher heart rate level than all other dances in the program, with a mean heart rate change of 52.6 bpm. Girls (127.3 bpm) achieved marginally higher heart rates (p = .059) than boys (121.1 bpm).

  14. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.

  15. Pace's Maxims for Homegrown Library Projects. Coming Full Circle

    ERIC Educational Resources Information Center

    Pace, Andrew K.

    2005-01-01

    This article discusses six maxims by which to run library automation. The following maxims are discussed: (1) Solve only known problems; (2) Avoid changing data to fix display problems; (3) Aut viam inveniam aut faciam; (4) If you cannot make it yourself, buy something; (5) Kill the alligator closest to the boat; and (6) Just because yours is…

  16. The Negative Consequences of Maximizing in Friendship Selection.

    PubMed

    Newman, David B; Schug, Joanna; Yuki, Masaki; Yamada, Junko; Nezlek, John B

    2017-02-27

    Previous studies have shown that the maximizing orientation, reflecting a motivation to select the best option among a given set of choices, is associated with various negative psychological outcomes. In the present studies, we examined whether these relationships extend to friendship selection and how the number of options for friends moderated these effects. Across 5 studies, maximizing in selecting friends was negatively related to life satisfaction, positive affect, and self-esteem, and was positively related to negative affect and regret. In Study 1, a maximizing in selecting friends scale was created, and regret mediated the relationships between maximizing and well-being. In a naturalistic setting in Studies 2a and 2b, the tendency to maximize among those who participated in the fraternity and sorority recruitment process was negatively related to satisfaction with their selection, and positively related to regret and negative affect. In Study 3, daily levels of maximizing were negatively related to daily well-being, and these relationships were mediated by daily regret. In Study 4, we extended the findings to samples from the U.S. and Japan. When participants who tended to maximize were faced with many choices, operationalized as the daily number of friends met (Study 3) and relational mobility (Study 4), the opportunities to regret a decision increased and further diminished well-being. These findings imply that, paradoxically, attempts to maximize when selecting potential friends is detrimental to one's well-being. (PsycINFO Database Record

  17. Detrimental Relations of Maximization with Academic and Career Attitudes

    ERIC Educational Resources Information Center

    Dahling, Jason J.; Thompson, Mindi N.

    2013-01-01

    Maximization refers to a decision-making style that involves seeking the single best option when making a choice, which is generally dysfunctional because people are limited in their ability to rationally evaluate all options and identify the single best outcome. The vocational consequences of maximization are examined in two samples, college…

  18. Smokeless tobacco, sport and the heart.

    PubMed

    Chagué, Frédéric; Guenancia, Charles; Gudjoncik, Aurélie; Moreau, Daniel; Cottin, Yves; Zeller, Marianne

    2015-01-01

    Smokeless tobacco (snuff) is a finely ground or shredded tobacco that is sniffed through the nose or placed between the cheek and gum. Chewing tobacco is used by putting a wad of tobacco inside the cheek. Smokeless tobacco is widely used by young athletes to enhance performance because nicotine improves some aspects of physiology. However, smokeless tobacco has harmful health effects, including cardiovascular disorders, linked to nicotine physiological effects, mainly through catecholamine release. Nicotine decreases heart rate variability and the ventricular fibrillation threshold, and promotes the occurrence of various arrhythmias; it also impairs endothelial-dependent vasodilation and could therefore promote premature atherogenesis. At rest, heart rate, blood pressure, inotropism, cardiac output and myocardial oxygen consumption are increased by nicotine, leading to an imbalance between myocardial oxygen demand and supply. The same occurs at submaximal levels of exercise. These increases are accompanied by a rise in systemic resistances. At maximal exercise, heart rate, cardiac output and maximal oxygen uptake (V˙O2max) are unaffected by nicotine. Because endothelial dysfunction is promoted by nicotine, paradoxical coronary vasoconstriction may occur during exercise and recovery. Nicotine induces a decrease in muscular strength and impairs anaerobic performance. However, nicotine is used in sports as it diminishes anxiety, enhances concentration and agility, improves aerobic performance and favours weight control. Importantly, smokeless tobacco, similar to cigarette smoking, leads to nicotine dependence through dopaminergic pathways. Smokeless tobacco has harmful cardiovascular effects and is addictive: it fulfils all the criteria for inclusion in the World Anti-Doping Agency prohibited list as a doping product. Smokeless tobacco use in sporting activities must be discouraged.

  19. Heart Truth for Women: If You Have Heart Disease

    MedlinePlus

    THE FOR WO MEN TRUTH THE HEART TRUTH FoR WoMEN: iF You HAVE HEART DisEAsE If you have heart disease, or think you do, it’s vital to take action to protect your heart health. Fortunately, there’s a lot you can do. ...

  20. Heart to Heart Art: Empowering Homeless Children and Youth

    ERIC Educational Resources Information Center

    Shepard, Jerri; Booth, Deborah

    2009-01-01

    This article describes Heart to Heart Art, an after-school program developed for homeless children and youth at the YWCA in Spokane, Washington. Pre-service teacher candidates from a local university create meaningful activities that engage homeless students in visual art, music, drama, cooking, and community service. Heart to Heart Art was…

  1. Effects of thyroid state on respiration of perfused rat and guinea pig hearts

    SciTech Connect

    Read, L.C.; Wallace, P.G.; Berry, M.N. )

    1987-09-01

    The effects of thyroid state on the respiration of the isolated heart were investigated using retrograde perfused rat and guinea pig hearts. In both species, hypothyroidism caused a marked depression in circulating thyroid hormone concentrations and in the respiration of the isolated, retrograde perfused heart. Hypothyroidism was caused by injecting animals with Na{sup 131}I. The effects on myocardial respiration could be attributed to changes in the contraction frequency and in the oxygen consumption per beat, with little contribution from basal respiration. Treatment of animals with thyroxine elevated plasma thyroid hormones to a similar extent in rats and guinea pigs. In the latter, thyroxine treatment was associated with substantial increases in the contraction frequency and the oxygen consumption per beat of the isolated heart. In contrast, only small changes were apparent in the retrograde perfused rat heart, observations that were confirmed in rat hearts perfused at near physiological work loads. It was concluded that rat hearts isolated from normal animals function at near maximal thyroid state, in contrast to the guinea pig heart, which requires higher circulating concentrations of thyroid hormones to attain maximal responses.

  2. Heart Surgery: MedlinePlus Health Topic

    MedlinePlus

    ... disease, or peripheral arterial disease. NIH: National Heart, Lung, and Blood Institute Start Here Cardiac Procedures and Surgeries (American Heart Association) What Is Heart Surgery? (National Heart, Lung, and Blood Institute) Latest News Taking Statins May Boost Heart ...

  3. General review of maximal aerobic velocity measurement at laboratory. Proposition of a new simplified protocol for maximal aerobic velocity assessment.

    PubMed

    Berthon, P; Fellmann, N

    2002-09-01

    The maximal aerobic velocity concept developed since eighties is considered as either the minimal velocity which elicits the maximal aerobic consumption or as the "velocity associated to maximal oxygen consumption". Different methods for measuring maximal aerobic velocity on treadmill in laboratory conditions have been elaborated, but all these specific protocols measure V(amax) either during a maximal oxygen consumption test or with an association of such a test. An inaccurate method presents a certain number of problems in the subsequent use of the results, for example in the elaboration of training programs, in the study of repeatability or in the determination of individual limit time. This study analyzes 14 different methods to understand their interests and limits in view to propose a general methodology for measuring V(amax). In brief, the test should be progressive and maximal without any rest period and of 17 to 20 min total duration. It should begin with a five min warm-up at 60-70% of the maximal aerobic power of the subjects. The beginning of the trial should be fixed so that four or five steps have to be run. The duration of the steps should be three min with a 1% slope and an increasing speed of 1.5 km x h(-1) until complete exhaustion. The last steps could be reduced at two min for a 1 km x h(-1) increment. The maximal aerobic velocity is adjusted in relation to duration of the last step.

  4. Heart, front view (image)

    MedlinePlus

    ... the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen ... carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen ...

  5. [Heart involvement in sarcoglycanopathies].

    PubMed

    Fayssoil, A; Nardi, O; Orlikowski, D; Annane, D

    2012-11-01

    Sarcoglycanopathies (SG) are autosomic recessive muscular dystrophies, secondary to mutations of the sarcoglycan complex. Clinical pictures include muscle weakness affecting mainly the proximal limb girdle musculature. We review heart involvement in this group of disease.

  6. Sleepless Nights, Unhealthy Hearts?

    MedlinePlus

    ... heart attack or stroke, a research review from China suggests. "We found that difficulty initiating sleep, difficulty ... fully understood, said He, a graduate student at China Medical University in Shenyang. However, the study doesn' ...

  7. Heart Truth for Latinas

    MedlinePlus

    ... salt and other forms of sodium, getting regular physical activity, maintaining a healthy weight, and, if you drink ... are physically inactive—they do no spare-time physical activity. Regular physical activity lowers your risk of heart ...

  8. Keeping Hearts Pumping

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A collaboration between NASA, Dr. Michael DeBakey, Dr. George Noon, and MicroMed Technology, Inc., resulted in a life-saving heart pump for patients awaiting heart transplants. The MicroMed DeBakey VAD functions as a "bridge to heart transplant" by pumping blood throughout the body to keep critically ill patients alive until a donor heart is available. Weighing less than 4 ounces and measuring 1 inch by 3 inches, the pump is approximately one-tenth the size of other currently marketed pulsatile VADs. This makes it less invasive and ideal for smaller adults and children. Because of the pump's small size, less than 5 percent of the patients implanted developed device-related infections. It can operate up to 8 hours on batteries, giving patients the mobility to do normal, everyday activities.The MicroMed DeBakey VAD is a registered trademark of MicroMed Technology, Inc.

  9. Types of Heart Block

    MedlinePlus

    ... is less serious than Mobitz type II. The animation below shows how your heart's electrical system works. ... block. Click the "start" button to play the animation. Written and spoken explanations are provided with each ...

  10. Heart failure overview

    MedlinePlus

    ... heart failure: Fast or difficult breathing Leg swelling (edema) Neck veins that stick out (are distended) Sounds ( ... pacemaker High blood pressure Implantable cardioverter-defibrillator Pulmonary edema Stable angina Ventricular assist device Patient Instructions ACE ...

  11. Heart Diseases and Disorders

    MedlinePlus

    ... damage the heart muscle or valves. Electrical Disorders Arrhythmias that start in the heart’s upper chambers, the ... low blood count) or hyperthyroidism (overactive thyroid gland). Arrhythmias that originate in the heart’s lower chambers, the ...

  12. What Causes Heart Block?

    MedlinePlus

    ... of congenital heart block occurs in babies whose mothers have autoimmune diseases, such as lupus. People who have these diseases make proteins called antibodies that attack and damage the body's tissues or ...

  13. Open heart surgery

    MedlinePlus

    ... Cornwell LD, Bakaeen FG. Acquired heart disease: coronary insufficiency. In: Townsend CM Jr, Beauchamp RD, Evers BM, ... Pulmonary atresia Tetralogy of Fallot Total anomalous pulmonary venous return Ventricular septal defect Review Date 4/13/ ...

  14. Hypertensive heart disease

    MedlinePlus

    ... DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 10th ed. Philadelphia, PA: Elsevier ... Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, ...

  15. Heart bypass surgery - discharge

    MedlinePlus

    ... Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest . 2012;141(2 ... surgery Heart failure - overview High blood cholesterol levels Smoking - ...

  16. Heart pacemaker - discharge

    MedlinePlus

    ... please enable JavaScript. A pacemaker is a small, battery-operated device that senses when your heart is ... pacemaker is placed under your skin. These include: Battery powered cordless tools (such as screwdrivers and drills) ...

  17. Caffeine and Heart Disease

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  18. Alcohol and Heart Health

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  19. Meditation and Heart Health

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  20. Protein and Heart Health

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  1. Target Heart Rate Calculator

    MedlinePlus

    ... try exercising within the upper range of your target zone. (If just beginning an exercise program, consult your doctor first.) Source: National Heart, Lung, and Blood Institute ... Information Cancer Prevention & Detection Cancer Basics Signs & Symptoms of Cancer Treatments & Side ...

  2. Heart attack first aid

    MedlinePlus

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 ...

  3. Living with Heart Failure

    MedlinePlus

    ... help you in the future. Follow Your Treatment Plan Treatment can relieve your symptoms and make daily ... or nurse about getting flu and pneumonia vaccines. Plan Ahead If you have heart failure, it's important ...

  4. Left heart ventricular angiography

    MedlinePlus

    ... pressure when the catheter is inserted. Occasionally, a flushing sensation or a feeling that you need to ... E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 10th ed. Philadelphia, PA: Elsevier Saunders; 2015: ...

  5. Problem: Heart Valve Stenosis

    MedlinePlus

    ... valve . Learn about the different types of stenosis: Aortic stenosis Tricuspid stenosis Pulmonary stenosis Mitral stenosis Outlook for ... Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - ...

  6. Heart valve surgery - discharge

    MedlinePlus

    ... surgery - minimally invasive Aortic valve surgery - open Bicuspid aortic valve Endocarditis Heart valve surgery Mitral valve prolapse Mitral valve surgery - minimally invasive Mitral valve surgery - open Pulmonary valve stenosis Smoking - tips on how to quit Patient Instructions ...

  7. Heart Disease (For Kids)

    MedlinePlus

    ... a variety of problems, including high blood pressure , hardening of the arteries, chest pain, heart attacks, and ... teer-ee-oh-skluh-ROW-sus): also called hardening of the arteries, arteriosclerosis means the arteries become ...

  8. Heart transplant - slideshow

    MedlinePlus

    ... ency/presentations/100086.htm Heart transplant - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  9. Congenital Heart Information Network

    MedlinePlus

    ... Baemayr for The Congenital Heart Information Network Exempt organization under Section 501(c)3. Copyright ©1996 - 2016 C.H.I.N. All rights reserved TX4-390-685 Original site design and HTML by Panoptic Communications

  10. Heart failure in pregnancy.

    PubMed

    Rutherford, John D

    2012-12-01

    With increasing maternal age and the presence of comorbid conditions such as hypertension, cardiovascular assessment and monitoring is the responsibility of all clinicians caring for pregnant patients. Furthermore, there are specific conditions, such as mitral stenosis, peripartum cardiomyopathy, and preeclampsia, that can be associated with heart failure and secondary maternal (and fetal) mortality and morbidity. The important causes of heart failure in pregnancy are discussed.

  11. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  12. Risks for Heart Disease & Stroke

    MedlinePlus

    ... for Heart Disease & Stroke Risks for Heart Disease & Stroke About 1.5 million heart attacks and strokes happen every year in the United States. You ... some of your risks for heart disease and stroke, but you can manage many of your risks ...

  13. Heart valve surgery - series (image)

    MedlinePlus

    There are four valves in the heart: aortic valve, mitral valve, tricuspid valve, and pulmonary valve. The valves are designed to control the direction of blood flow through the heart. The opening and closing of the heart valves produce the heart-beat sounds.

  14. Decompensated heart failure

    PubMed Central

    Mangini, Sandrigo; Pires, Philippe Vieira; Braga, Fabiana Goulart Marcondes; Bacal, Fernando

    2013-01-01

    ABSTRACT Heart failure is a disease with high incidence and prevalence in the population. The costs with hospitalization for decompensated heart failure reach approximately 60% of the total cost with heart failure treatment, and mortality during hospitalization varies according to the studied population, and could achieve values of 10%. In patients with decompensated heart failure, history and physical examination are of great value for the diagnosis of the syndrome, and also can help the physician to identify the beginning of symptoms, and give information about etiology, causes and prognosis of the disease. The initial objective of decompensated heart failure treatment is the hemodynamic and symptomatic improvement preservation and/or improvement of renal function, prevention of myocardial damage, modulation of the neurohormonal and/or inflammatory activation and control of comorbidities that can cause or contribute to progression of the syndrome. According to the clinical-hemodynamic profile, it is possible to establish a rational for the treatment of decompensated heart failure, individualizing the proceedings to be held, leading to reduction in the period of hospitalization and consequently reducing overall mortality. PMID:24136770

  15. [Heart failure and comorbidities].

    PubMed

    Boully, Clémence; Hanon, Olivier

    2015-03-01

    Heart failure is a frequent disease in the elderly. Its clinical presentation is less typical and the prognosis more severe than in younger subjects because heart failure occurs in patients with multiple comorbidities. A comprehensive geriatric assessment should therefore be performed to detect the vulnerabilities and manage the comorbidities. The main diseases associated with heart failure are dementia, depression, malnutrition, atrial fibrillation, coronary artery disease, orthostatic hypotension, renal failure, anemia and iron deficiency. Comorbidities worsen heart failure and makes its treatment more difficult. The identification and treatment of comorbidities improve the prognosis in terms of mortality but especially in terms of quality of life. Caution with drugs is necessary because of pharmacokinetic or pharmacodynamic changes related to aging and the comorbidities. In this context, clinical and laboratory monitoring should be increased, mostly during an acute event (acute heart failure, infection, dehydration, fall, new therapy…). Therefore, the follow-up of elderly patients with heart failure requires a multidisciplinary approach that involves close cooperation between cardiologists, geriatricians, general practitioners, nurses, and pharmacists.

  16. Can monkeys make investments based on maximized pay-off?

    PubMed

    Steelandt, Sophie; Dufour, Valérie; Broihanne, Marie-Hélène; Thierry, Bernard

    2011-03-10

    Animals can maximize benefits but it is not known if they adjust their investment according to expected pay-offs. We investigated whether monkeys can use different investment strategies in an exchange task. We tested eight capuchin monkeys (Cebus apella) and thirteen macaques (Macaca fascicularis, Macaca tonkeana) in an experiment where they could adapt their investment to the food amounts proposed by two different experimenters. One, the doubling partner, returned a reward that was twice the amount given by the subject, whereas the other, the fixed partner, always returned a constant amount regardless of the amount given. To maximize pay-offs, subjects should invest a maximal amount with the first partner and a minimal amount with the second. When tested with the fixed partner only, one third of monkeys learned to remove a maximal amount of food for immediate consumption before investing a minimal one. With both partners, most subjects failed to maximize pay-offs by using different decision rules with each partner' quality. A single Tonkean macaque succeeded in investing a maximal amount to one experimenter and a minimal amount to the other. The fact that only one of over 21 subjects learned to maximize benefits in adapting investment according to experimenters' quality indicates that such a task is difficult for monkeys, albeit not impossible.

  17. Oxygen uptake in maximal effort constant rate and interval running.

    PubMed

    Pratt, Daniel; O'Brien, Brendan J; Clark, Bradley

    2013-01-01

    This study investigated differences in average VO2 of maximal effort interval running to maximal effort constant rate running at lactate threshold matched for time. The average VO2 and distance covered of 10 recreational male runners (VO2max: 4158 ± 390 mL · min(-1)) were compared between a maximal effort constant-rate run at lactate threshold (CRLT), a maximal effort interval run (INT) consisting of 2 min at VO2max speed with 2 minutes at 50% of VO2 repeated 5 times, and a run at the average speed sustained during the interval run (CR submax). Data are presented as mean and 95% confidence intervals. The average VO2 for INT, 3451 (3269-3633) mL · min(-1), 83% VO2max, was not significantly different to CRLT, 3464 (3285-3643) mL · min(-1), 84% VO2max, but both were significantly higher than CR sub-max, 3464 (3285-3643) mL · min(-1), 76% VO2max. The distance covered was significantly greater in CLRT, 4431 (4202-3731) metres, compared to INT and CR sub-max, 4070 (3831-4309) metres. The novel finding was that a 20-minute maximal effort constant rate run uses similar amounts of oxygen as a 20-minute maximal effort interval run despite the greater distance covered in the maximal effort constant-rate run.

  18. Maximal oxygen uptake, ventilatory thresholds and mechanical power during cycling in tropical climate in Guadeloupean elite cyclists.

    PubMed

    Hue, O; Antoine-Jonville, S; Galy, O; Blonc, S

    2010-11-01

    The Tropical climate imposes a high level of physiological stress, which could modify the target heart rate in training load prescription, as the recommendations are often determined by maximal oxygen uptake testing in temperature-neutral laboratories. To test this hypothesis, 7 high-level cyclists performed two randomised maximal tests in neutral (19.2±0.9°C; 51.7±1.3% RH) and Tropical environment (25.8±1.1°C; 63.7±2.3% RH). Neither maximal oxygen uptake nor ventilatory threshold was influenced by the environmental conditions. However, ventilation (p<0.005) and the respiratory equivalent in O(2) (p<0.05) were significantly higher in the Tropical environment, whereas maximal power output and the time to attain maximal oxygen uptake were significantly lower (p<0.05 for both). Moreover, the ventilatory cost of cycling (expressed in LW(-1)) was significantly greater in the Tropical condition (0.40±0.03LW(-1) vs. 0.32±0.05LW(-1), in Tropical vs. Neutral; condition effect: p<0.005; condition × time: p<0.001). Rectal temperature was influenced by neither the environmental conditions nor exercise (36.7±0.1 and 37.0±0.1°C vs. 36.8±0.1 and 37.1±0.2°C, in Tropical vs. Neutral, before and after exercise) but was influenced by condition × time (p<0.05). The heart rate (HR) values usually used for training prescription were not significantly different (154±5bpm vs. 156±4bpm and 172±4bpm vs. 167±4bpm in Tropical vs. Neutral climate, for the first and second thresholds, respectively). We concluded that the usual parameters measured during maximal exercise to establish training programs are not impaired in moderate Tropical environment. Nevertheless, the thermal stress attested by the increased ventilatory cost of cycling could have prevented the cyclists from performing a true maximal test in Tropical conditions.

  19. On the Ribosomal Density that Maximizes Protein Translation Rate

    PubMed Central

    Zarai, Yoram; Margaliot, Michael; Tuller, Tamir

    2016-01-01

    During mRNA translation, several ribosomes attach to the same mRNA molecule simultaneously translating it into a protein. This pipelining increases the protein translation rate. A natural and important question is what ribosomal density maximizes the protein translation rate. Using mathematical models of ribosome flow along both a linear and a circular mRNA molecules we prove that typically the steady-state protein translation rate is maximized when the ribosomal density is one half of the maximal possible density. We discuss the implications of our results to endogenous genes under natural cellular conditions and also to synthetic biology. PMID:27861564

  20. Building hospital TQM teams: effective polarity analysis and maximization.

    PubMed

    Hurst, J B

    1996-09-01

    Building and maintaining teams require careful attention to and maximization of such polar opposites (¿polarities¿) as individual and team, directive and participatory leadership, task and process, and stability and change. Analyzing systematic elements of any polarity and listing blocks, supports, and flexible ways to maximize it will prevent the negative consequences that occur when treating a polarity like a solvable problem. Flexible, well-timed shifts from pole to pole result in the maximization of upside and minimization of downside consequences.

  1. Cardiovascular determinants of maximal oxygen consumption in upright and supine posture at the end of prolonged bed rest in humans.

    PubMed

    Bringard, Aurélien; Pogliaghi, Silvia; Adami, Alessandra; De Roia, Gabriela; Lador, Frédéric; Lucini, Daniela; Pizzinelli, Paolo; Capelli, Carlo; Ferretti, Guido

    2010-06-30

    We tested the hypothesis that, after bed rest, maximal oxygen consumption ( VO₂max ) decreases more upright than supine, because of adequate cardiovascular response supine, but not upright. On 9 subjects, we determined VO₂max and maximal cardiac output (Q ) upright and supine, before and after (reambulation day upright, the following day supine) 35-day bed rest, by classical steady state protocol. Oxygen consumption, heart rate (f(H)) and stroke volume (Q(st)) were measured by a metabolic cart, electrocardiography and Modelflow from pulse pressure profiles, respectively. We computed Q as f(H) times Q(st), and systemic oxygen flow ( QaO₂) as Q. times arterial oxygen concentration, obtained after haemoglobin and arterial oxygen saturation measurements. Before bed rest, all parameters at maximal exercise were similar upright and supine. After bed rest, VO₂max was lower (p<0.05) than before, both upright (-38.6%) and supine (-17.0%), being 30.8% higher supine than upright. Maximal Q(st) decreased upright (-44.3%), but not supine (+3.7%), being 98.9% higher supine than upright. Maximal Q decreased upright (-45.1%), but not supine (+9.0%), being higher supine than upright (+98.4%). Maximal QaO₂ decreased upright (-37.8%), but not supine (+14.8%), being higher (+74.8%) upright than supine. After bed rest, the cardiovascular response (i) did not affect VO₂max supine, (ii) partially explained the VO₂max decrease upright, and (iii) caused the VO₂max differences between postures. We speculate that impaired peripheral oxygen transfer and/or utilisation may explain the VO₂max decrease supine and the fraction of VO₂max decrease upright unexplained by cardiovascular responses.

  2. Heart Rate and Energy Expenditure in Division I Field Hockey Players During Competitive Play.

    PubMed

    Sell, Katie M; Ledesma, Allison B

    2016-08-01

    Sell, KM and Ledesma, AB. Heart rate and energy expenditure in Division I field hockey players during competitive play. J Strength Cond Res 30(8): 2122-2128, 2016-The purpose of this study was to quantify energy expenditure and heart rate data for Division I female field hockey players during competitive play. Ten female Division I collegiate field hockey athletes (19.8 ± 1.6 years; 166.4 ± 6.1 cm; 58.2 ± 5.3 kg) completed the Yo-Yo intermittent endurance test to determine maximal heart rate. One week later, all subjects wore a heart rate monitor during a series of 3 matches in an off-season competition. Average heart rate (AvHR), average percentage of maximal heart rate (AvHR%), peak exercise heart rate (PExHR), and percentage of maximal heart rate (PExHR%), time spent in each of the predetermined heart rate zones, and caloric expenditure per minute of exercise (kcalM) were determined for all players. Differences between positions (backs, midfielders, and forwards) were assessed. No significant differences in AvHR, AvHR%, PExHR, PExHR%, and %TM were observed between playing positions. The AvHR% and PExHR% for each position fell into zones 4 (77-93% HRmax) and 5 (>93% HRmax), respectively, and significantly more time was spent in zone 4 compared with zones 1, 2, 3, and 5 across all players (p ≤ 0.05). The kcalM reflected very heavy intensity exercise. The results of this study will contribute toward understanding the sport-specific physiological demands of women's field hockey and has specific implications for the duration and schedule of training regimens.

  3. The Effects of Vibration During Maximal Graded Cycling Exercise: A Pilot Study

    PubMed Central

    Filingeri, Davide; Jemni, Monèm; Bianco, Antonino; Zeinstra, Edzard; Jimenez, Alfonso

    2012-01-01

    Whole Body Vibration training is studied and used in different areas, related to sport performance and rehabilitation. However, few studies have investigated the effects of Vibration (Vib) exposure on aerobic performance through the application of this concept to cycling exercise. A specifically designed vibrating cycloergometer, the powerBIKE™, was used to compare the effects of Vib cycling exercise and normal cycling on different physiological parameters during maximal graded exercise test. Twelve recreationally active male adults (25 ± 4.8 yrs; 181.33 ± 5.47 cm; 80.66 ± 11.91 kg) performed two maximal incremental cycling tests with and without Vib in a block-randomized order. The protocol consisted of a 4 min warm up at 70 rev·min-1 followed by incremental steps of 3 min each. Cycling cadence was increased at each step by 10 rev·min-1 until participants reached their volitional exhaustion. Respiratory gases (VO2, VCO2), Heart Rate, Blood Lactate and RPE were collected during the test. Paired t-tests and Cor-relation Coefficients were used for statistical analysis. A significantly greater (P<0.05) response in the VO2, HR, BLa and RPE was observed during the Vib trial compare to normal cycling. No significant differences were found in the maximal aerobic power (Vib 34.32 ± 9.70 ml·kg-1·min-1; no Vib 40.11 ± 9.49 ml·kg-1·min-1). Adding Vib to cycling exercise seems eliciting a quicker energetic demand during maximal exercise. However, mechanical limitations of the vibrating prototype could have affected the final outcomes. Future studies with more comparative setting are recommended to deeply appraise this concept. Key points There is strong evidence to suggest that acute indirect vibrations act on muscle to enhance force, power, flexibility, balance and proprioception. There is a lack of knowledge regarding the effects of applying Vib to dynamic aerobic exercise. Added vibrations to cycling exercise seem producing a quicker energetic demand during

  4. Sensitivity to conversational maxims in deaf and hearing children.

    PubMed

    Surian, Luca; Tedoldi, Mariantonia; Siegal, Michael

    2010-09-01

    We investigated whether access to a sign language affects the development of pragmatic competence in three groups of deaf children aged 6 to 11 years: native signers from deaf families receiving bimodal/bilingual instruction, native signers from deaf families receiving oralist instruction and late signers from hearing families receiving oralist instruction. The performance of these children was compared to a group of hearing children aged 6 to 7 years on a test designed to assess sensitivity to violations of conversational maxims. Native signers with bimodal/bilingual instruction were as able as the hearing children to detect violations that concern truthfulness (Maxim of Quality) and relevance (Maxim of Relation). On items involving these maxims, they outperformed both the late signers and native signers attending oralist schools. These results dovetail with previous findings on mindreading in deaf children and underscore the role of early conversational experience and instructional setting in the development of pragmatics.

  5. Optimizing Air Force Depot Programming to Maximize Operational Capability

    DTIC Science & Technology

    2014-03-27

    34 vii LINGO Component... LINGO Code with Notional Data by Model .................................. 45 RAND Formulation to Maximize Operational Capability...Minimize Cost ...................................................................................... 49 Appendix B –Final LINGO Code by Model

  6. Interpreting Negative Results in an Angle Maximization Problem.

    ERIC Educational Resources Information Center

    Duncan, David R.; Litwiller, Bonnie H.

    1995-01-01

    Presents a situation in which differential calculus is used with inverse trigonometric tangent functions to maximize an angle measure. A negative distance measure ultimately results, requiring a reconsideration of assumptions inherent in the initial figure. (Author/MKR)

  7. On maximal parabolic regularity for non-autonomous parabolic operators

    NASA Astrophysics Data System (ADS)

    Disser, Karoline; ter Elst, A. F. M.; Rehberg, Joachim

    2017-02-01

    We consider linear inhomogeneous non-autonomous parabolic problems associated to sesquilinear forms, with discontinuous dependence of time. We show that for these problems, the property of maximal parabolic regularity can be extrapolated to time integrability exponents r ≠ 2. This allows us to prove maximal parabolic Lr-regularity for discontinuous non-autonomous second-order divergence form operators in very general geometric settings and to prove existence results for related quasilinear equations.

  8. Power Converters Maximize Outputs Of Solar Cell Strings

    NASA Technical Reports Server (NTRS)

    Frederick, Martin E.; Jermakian, Joel B.

    1993-01-01

    Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

  9. [Maximal anaerobic capacity of man in a modified Wingate test].

    PubMed

    Ushakov, B B; Chelnokova, E V

    1992-01-01

    We studied the possibility of using a 380B Siemens-Elema (Sweden) bicycle ergometer to determine the maximal anaerobic capacity of healthy subjects during a modified Wingate test. Exercise was performed under stable moment conditions, with calculation of braking resistance on the basis of the subjects lean body mass. The values of total work performed and maximal power may be used for comparative evaluation of physical work capacity in participants of training and rehabilitation programs.

  10. Maximally Permissive Composition of Actors in Ptolemy II

    DTIC Science & Technology

    2013-03-20

    Maximally Permissive Composition of Actors in Ptolemy II Marten Lohstroh Electrical Engineering and Computer Sciences University of California at...3. DATES COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Maximally Permissive Composition of Actors in Ptolemy II 5a. CONTRACT NUMBER...addresses the problem of handling dynamic data, in the statically typed, actor-oriented modeling environment called Ptolemy II. It explores the possibilities

  11. A new augmentation based algorithm for extracting maximal chordal subgraphs

    SciTech Connect

    Bhowmick, Sanjukta; Chen, Tzu-Yi; Halappanavar, Mahantesh

    2014-10-18

    If every cycle of a graph is chordal length greater than three then it contains an edge between non-adjacent vertices. Chordal graphs are of interest both theoretically, since they admit polynomial time solutions to a range of NP-hard graph problems, and practically, since they arise in many applications including sparse linear algebra, computer vision, and computational biology. A maximal chordal subgraph is a chordal subgraph that is not a proper subgraph of any other chordal subgraph. Existing algorithms for computing maximal chordal subgraphs depend on dynamically ordering the vertices, which is an inherently sequential process and therefore limits the algorithms’ parallelizability. In our paper we explore techniques to develop a scalable parallel algorithm for extracting a maximal chordal subgraph. We demonstrate that an earlier attempt at developing a parallel algorithm may induce a non-optimal vertex ordering and is therefore not guaranteed to terminate with a maximal chordal subgraph. We then give a new algorithm that first computes and then repeatedly augments a spanning chordal subgraph. After proving that the algorithm terminates with a maximal chordal subgraph, we then demonstrate that this algorithm is more amenable to parallelization and that the parallel version also terminates with a maximal chordal subgraph. That said, the complexity of the new algorithm is higher than that of the previous parallel algorithm, although the earlier algorithm computes a chordal subgraph which is not guaranteed to be maximal. Finally, we experimented with our augmentation-based algorithm on both synthetic and real-world graphs. We provide scalability results and also explore the effect of different choices for the initial spanning chordal subgraph on both the running time and on the number of edges in the maximal chordal subgraph.

  12. A new augmentation based algorithm for extracting maximal chordal subgraphs

    DOE PAGES

    Bhowmick, Sanjukta; Chen, Tzu-Yi; Halappanavar, Mahantesh

    2014-10-18

    If every cycle of a graph is chordal length greater than three then it contains an edge between non-adjacent vertices. Chordal graphs are of interest both theoretically, since they admit polynomial time solutions to a range of NP-hard graph problems, and practically, since they arise in many applications including sparse linear algebra, computer vision, and computational biology. A maximal chordal subgraph is a chordal subgraph that is not a proper subgraph of any other chordal subgraph. Existing algorithms for computing maximal chordal subgraphs depend on dynamically ordering the vertices, which is an inherently sequential process and therefore limits the algorithms’more » parallelizability. In our paper we explore techniques to develop a scalable parallel algorithm for extracting a maximal chordal subgraph. We demonstrate that an earlier attempt at developing a parallel algorithm may induce a non-optimal vertex ordering and is therefore not guaranteed to terminate with a maximal chordal subgraph. We then give a new algorithm that first computes and then repeatedly augments a spanning chordal subgraph. After proving that the algorithm terminates with a maximal chordal subgraph, we then demonstrate that this algorithm is more amenable to parallelization and that the parallel version also terminates with a maximal chordal subgraph. That said, the complexity of the new algorithm is higher than that of the previous parallel algorithm, although the earlier algorithm computes a chordal subgraph which is not guaranteed to be maximal. Finally, we experimented with our augmentation-based algorithm on both synthetic and real-world graphs. We provide scalability results and also explore the effect of different choices for the initial spanning chordal subgraph on both the running time and on the number of edges in the maximal chordal subgraph.« less

  13. Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity

    NASA Technical Reports Server (NTRS)

    Engelke, K. A.; Doerr, D. F.; Crandall, C. G.; Convertino, V. A.

    1996-01-01

    We tested the hypothesis that one bout of maximal exercise performed at the conclusion of prolonged simulated microgravity would improve blood pressure stability during an orthostatic challenge. Heart rate (HR), mean arterial blood pressure (MAP), norepinephrine (NE), epinephrine (E), arginine vasopressin (AVP), plasma renin activity (PRA), atrial natriuretic peptide (ANP), cardiac output (Q), forearm vascular resistance (FVR), and changes in leg volume were measured during lower body negative pressure (LBNP) to presyncope in seven subjects immediately prior to reambulation from 16 days of 6 degrees head-down tilt (HDT) under two experimental conditions: 1) after maximal supine cycle ergometry performed 24 h before returning to the upright posture (exercise) and 2) without exercise (control). After HDT, the reduction of LBNP tolerance time from pre-HDT levels was greater (P = 0.041) in the control condition (-2.0 +/- 0.2 min) compared with the exercise condition (-0.4 +/- 0.2 min). At presyncope after HDT, FVR and NE were higher (P < 0.05) after exercise compared with control, whereas MAP, HR, E, AVP, PRA, ANP, and leg volume were similar in both conditions. Plasma volume (PV) and carotid-cardiac baroreflex sensitivity were reduced after control HDT, but were restored by the exercise treatment. Maintenance of orthostatic tolerance by application of acute intense exercise after 16 days of simulated microgravity was associated with greater circulating levels of NE, vasoconstriction, Q, baroreflex sensitivity, and PV.

  14. Mechanical Circulatory Support and the Role of LVADs in Heart Failure Therapy

    PubMed Central

    McLarty, Allison

    2015-01-01

    Heart failure is epidemic in the United States with a prevalence of over 5 million. The diagnosis carries a mortality risk of 50% at 5 years rivaling many diagnoses of cancer. Heart transplantation, long the “gold standard” treatment for end stage heart failure unresponsive to maximal medical therapy falls way short of meeting the need with only about 2,000 transplants performed annually in the United States due to donor limitation. Left ventricular devices have emerged as a viable option for patients as both a “bridge to transplantation” and as a final “destination therapy”. PMID:25983564

  15. [Heart failure and anemia].

    PubMed

    Reda, S; Motloch, L J; Hoppe, U C

    2013-09-01

    Chronic heart failure has an age-dependent prevalence of 2% and is therefore one of the most frequent diseases in western societies. A reduced hemoglobin concentration according to the definition of the World Health Organization is a common comorbidity affecting more than half of all heart failure patients. Elderly patients, patients suffering from renal impairment and women are more likely to develop anemia but a definitive etiology of anemia is only identified in the minority of cases. Anemia is associated with a poor clinical status and a greater risk of hospitalization and is a predictive factor for increased mortality. The incidence of anemia appears to increase with a poorer functional class. Intravenous iron therapy improves the exercise capacity in patients with systolic heart failure and iron deficiency and is currently being recommended for patients with persistent symptoms despite optimal medical and device therapy. However, erythropoietin-stimulating agents as a treatment for anemia in chronic heart failure have failed to improve clinical outcome in a large randomized trial. In patients with heart failure but with maintained ejection fraction, anemia is also associated with a poor prognosis. Specific therapeutic recommendations for these patients are still not available.

  16. Does the incremental shuttle walk test require maximal effort in young obese women?

    PubMed

    Jürgensen, S P; Trimer, R; Di Thommazo-Luporini, L; Dourado, V Z; Bonjorno-Junior, J C; Oliveira, C R; Arena, R; Borghi-Silva, A

    2016-07-11

    Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 - age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option.

  17. Heart transplantation in adults with congenital heart disease.

    PubMed

    Houyel, Lucile; To-Dumortier, Ngoc-Tram; Lepers, Yannick; Petit, Jérôme; Roussin, Régine; Ly, Mohamed; Lebret, Emmanuel; Fadel, Elie; Hörer, Jürgen; Hascoët, Sébastien

    2017-02-22

    With the advances in congenital cardiac surgery and postoperative care, an increasing number of children with complex congenital heart disease now reach adulthood. There are already more adults than children living with a congenital heart defect, including patients with complex congenital heart defects. Among these adults with congenital heart disease, a significant number will develop ventricular dysfunction over time. Heart failure accounts for 26-42% of deaths in adults with congenital heart defects. Heart transplantation, or heart-lung transplantation in Eisenmenger syndrome, then becomes the ultimate therapeutic possibility for these patients. This population is deemed to be at high risk of mortality after heart transplantation, although their long-term survival is similar to that of patients transplanted for other reasons. Indeed, heart transplantation in adults with congenital heart disease is often challenging, because of several potential problems: complex cardiac and vascular anatomy, multiple previous palliative and corrective surgeries, and effects on other organs (kidney, liver, lungs) of long-standing cardiac dysfunction or cyanosis, with frequent elevation of pulmonary vascular resistance. In this review, we focus on the specific problems relating to heart and heart-lung transplantation in this population, revisit the indications/contraindications, and update the long-term outcomes.

  18. Heart rate monitoring mobile applications

    PubMed Central

    2016-01-01

    Total number of times a heart beats in a minute is known as the heart rate. Traditionally, heart rate was measured using clunky gadgets but these days it can be measured with a smartphone’s camera. This can help you measure your heart rate anywhere and at anytime, especially during workouts so you can adjust your workout intensity to achieve maximum health benefits. With simple and easy to use mobile app, ‘Unique Heart Rate Monitor’, you can also maintain your heart rate history for personal reflection and sharing with a provider. PMID:28293594

  19. The acute effect of maximal exercise on plasma beta-endorphin levels in fibromyalgia patients

    PubMed Central

    Ghavidel-Parsa, Banafsheh; Rajabi, Sahar; Sanaei, Omid; Toutounchi, Mehrangiz

    2016-01-01

    Background This study aimed to investigate the effect of strenuous exercise on β-endorphine (β-END) level in fibromyalgia (FM) patients compared to healthy subjects. Methods We enrolled 30 FM patients and 15 healthy individuals. All study participants underwent a treadmill exercise test using modified Bruce protocol (M.Bruce). The goal of the test was achieving at least 70% of the predicted maximal heart rate (HRMax). The serum levels of β-END were measured before and after the exercise program. Measurements were done while heart rate was at least 70% of its predicted maximum. Results The mean ± the standard deviation (SD) of exercise duration in the FM and control groups were 24.26 ± 5.29 and 29.06 ± 3.26 minutes, respectively, indicating a shorter time to achieve the goal heart rate in FM patients (P < 0.003). Most FM patients attained 70% HRMax at lower stages (stage 2 and 3) of M.Bruce compared to the control group (70% versus 6.6%, respectively; P < 0.0001). Compared to healthy subjects, FM patients had lower serum β-END levels both in baseline and post-exercise status (Mean ± SD: 122.07 ± 28.56 µg/ml and 246.55 ± 29.57 µg/ml in the control group versus 90.12 ± 20.91 µg/ml and 179.80 ± 28.57 µg/ml in FM patients, respectively; P < 0.001). Conclusions We found that FM patients had lower levels of β-END in both basal and post-exercise status. Exercise increased serum the β-END level in both groups but the average increase in β-END in FM patients was significantly lower than in the control group. PMID:27738503

  20. How Accurate Is the Prediction of Maximal Oxygen Uptake with Treadmill Testing?

    PubMed Central

    Wicks, John R.; Oldridge, Neil B.

    2016-01-01

    Background Cardiorespiratory fitness measured by treadmill testing has prognostic significance in determining mortality with cardiovascular and other chronic disease states. The accuracy of a recently developed method for estimating maximal oxygen uptake (VO2peak), the heart rate index (HRI), is dependent only on heart rate (HR) and was tested against oxygen uptake (VO2), either measured or predicted from conventional treadmill parameters (speed, incline, protocol time). Methods The HRI equation, METs = 6 x HRI– 5, where HRI = maximal HR/resting HR, provides a surrogate measure of VO2peak. Forty large scale treadmill studies were identified through a systematic search using MEDLINE, Google Scholar and Web of Science in which VO2peak was either measured (TM-VO2meas; n = 20) or predicted (TM-VO2pred; n = 20) based on treadmill parameters. All studies were required to have reported group mean data of both resting and maximal HRs for determination of HR index-derived oxygen uptake (HRI-VO2). Results The 20 studies with measured VO2 (TM-VO2meas), involved 11,477 participants (median 337) with a total of 105,044 participants (median 3,736) in the 20 studies with predicted VO2 (TM-VO2pred). A difference of only 0.4% was seen between mean (±SD) VO2peak for TM- VO2meas and HRI-VO2 (6.51±2.25 METs and 6.54±2.28, respectively; p = 0.84). In contrast, there was a highly significant 21.1% difference between mean (±SD) TM-VO2pred and HRI-VO2 (8.12±1.85 METs and 6.71±1.92, respectively; p<0.001). Conclusion Although mean TM-VO2meas and HRI-VO2 were almost identical, mean TM-VO2pred was more than 20% greater than mean HRI-VO2. PMID:27875547

  1. Congestive Heart Failure.

    PubMed

    Scott, Michael C; Winters, Michael E

    2015-08-01

    Patients with acute decompensated heart failure are usually critically ill and require immediate treatment. However, most are not volume overloaded. Emergency department (ED) management is based on rapid initiation of noninvasive positive-pressure ventilation and aggressive titration of nitrates. Afterload reduction with an angiotensin-converting enzyme inhibitor can be considered. A diuretic should not be administered before optimal preload and afterload reduction has been achieved. Short-term inotropic therapy can be considered in select patients with cardiogenic shock and acute decompensated heart failure (ADHF) who fail to respond to standard therapy.

  2. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  3. Towards defining heart failure in adults with congenital heart disease.

    PubMed

    Bolger, Aidan P; Gatzoulis, Michael A

    2004-12-01

    Injury to the myocardium disrupts geometric integrity and results in changes to intracardiac pressure, wall stress and tension, and the pattern of blood flow through the heart. Significant disruption to pump function results in heart failure which is defined in terms of symptoms: breathlessness and fatigue, signs of salt and water retention, and neurohormonal activation. This syndrome most commonly occurs in the context of injury due to ischaemic heart disease and dilated cardiomyopathy but because patients with congenital heart disease (CHD) are born with sometimes gross distortions of cardiac anatomy they too are subject to the forces that drive heart failure. This paper explores the available data relating to the clinical and neurohormonal manifestations of heart failure in patients with congenital heart disease and describes how, by additionally exploring events at a cellular level, we may be able to arrive at a definition of heart failure relevant to this population.

  4. Epidemiology of coronary heart disease in women.

    PubMed

    Bello, Natalie; Mosca, Lori

    2004-01-01

    Cardiovascular disease (CVD) is the leading cause of mortality in women and a major cause of morbidity. Coronary heart disease (CHD) accounts for nearly half of all CVD deaths. Gender differences in CHD include a later age of onset for women, a greater prevalence of comorbid diseases, and differences in the initial manifestations of the disease. Traditional risk factors for CHD include tobacco use, hypertension, diabetes mellitus, dyslipidemia, obesity, sedentary lifestyle, and atherogenic diet. More recently identified risk factors in women include high sensitivity C-reactive protein (hsCRP), homocysteine, and lipoprotein (a). Appropriate management of risk factors is associated with a reduced incidence of CHD, yet poor implementation in women is widely documented. Barriers to optimal risk factor management in women should be identified and overcome in an effort to maximize the cardiovascular health of women.

  5. Heart Health: Learn the Truth About Your Heart

    MedlinePlus

    ... Bar Home Current Issue Past Issues Cover Story Heart Health Learn the Truth About Your Heart Past Issues / Winter 2009 Table of Contents For ... turn Javascript on. Photo: iStock February is American Heart Month. Now is the time to make sure ...

  6. Women's Heart Disease: Join the Heart Truth Community

    MedlinePlus

    ... this page please turn JavaScript on. Feature: Women's Heart Disease Join The Heart Truth Community Past Issues / Winter 2014 Table of Contents National Symbol The centerpiece of The Heart Truth ® is The Red Dress ® which was introduced ...

  7. Million Hearts: Key to Collaboration to Reduce Heart Disease

    ERIC Educational Resources Information Center

    Brinkman, Patricia

    2016-01-01

    Extension has taught successful classes to address heart disease, yet heart disease remains the number one killer in the United States. The U.S. government's Million Hearts initiative seeks collaboration among colleges, local and state health departments, Extension and other organizations, and medical providers in imparting a consistent message…

  8. How Will I Recover from My Heart Attack?

    MedlinePlus

    ... Understand Your Risk for Congenital Heart Defects Symptoms & Diagnosis of Congenital Heart Defects Care & Treatment for Congenital Heart Defects Congenital Heart Defects Tools & Resources Heart Attack About Heart Attacks Warning Signs of a Heart ...

  9. Disk Density Tuning of a Maximal Random Packing

    PubMed Central

    Ebeida, Mohamed S.; Rushdi, Ahmad A.; Awad, Muhammad A.; Mahmoud, Ahmed H.; Yan, Dong-Ming; English, Shawn A.; Owens, John D.; Bajaj, Chandrajit L.; Mitchell, Scott A.

    2016-01-01

    We introduce an algorithmic framework for tuning the spatial density of disks in a maximal random packing, without changing the sizing function or radii of disks. Starting from any maximal random packing such as a Maximal Poisson-disk Sampling (MPS), we iteratively relocate, inject (add), or eject (remove) disks, using a set of three successively more-aggressive local operations. We may achieve a user-defined density, either more dense or more sparse, almost up to the theoretical structured limits. The tuned samples are conflict-free, retain coverage maximality, and, except in the extremes, retain the blue noise randomness properties of the input. We change the density of the packing one disk at a time, maintaining the minimum disk separation distance and the maximum domain coverage distance required of any maximal packing. These properties are local, and we can handle spatially-varying sizing functions. Using fewer points to satisfy a sizing function improves the efficiency of some applications. We apply the framework to improve the quality of meshes, removing non-obtuse angles; and to more accurately model fiber reinforced polymers for elastic and failure simulations. PMID:27563162

  10. Panic Attack or Heart Attack?

    MedlinePlus

    ... with echocardiography. It is a good first-line test for a woman with symptoms and risk factors for heart disease. Echocardiography uses sound waves technology to give detailed information about the heart muscle, ...

  11. Heart failure - fluids and diuretics

    MedlinePlus

    ... In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook ... In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook ...

  12. Give your heart a workout

    MedlinePlus

    Exercise - heart workout; CAD prevention - workout; Cardiovascular disease prevention - workout ... Exercise helps your heart in several ways. Burns calories. This can help you lose extra pounds (kilograms) or stay at a healthy weight. ...

  13. Ejection Fraction Heart Failure Measurement

    MedlinePlus

    ... Thromboembolism Aortic Aneurysm More Ejection Fraction Heart Failure Measurement Updated:Feb 15,2017 The ejection fraction (EF) is an important measurement in determining how well your heart is pumping ...

  14. Angioplasty and stent placement - heart

    MedlinePlus

    ... syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. ... disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice ...

  15. Thrombolytic drugs for heart attack

    MedlinePlus

    ... syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. ... infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice ...

  16. All about Heart Rate (Pulse)

    MedlinePlus

    ... Giving for Heart.org Media for Heart.org Arrhythmia About Arrhythmia Why Arrhythmia Matters Understand Your Risk for Arrhythmia Symptoms, Diagnosis & Monitoring of Arrhythmia Prevention & Treatment of ...

  17. Heart Disease: Know Your Risk

    MedlinePlus

    A project of the U.S. Department of Health and Human Services Office on Women's Health Skip ... Heart disease risk factors you can't control Other possible heart disease risk factors Stroke: Know your ...

  18. Hispanics and Heart Disease, Stroke

    MedlinePlus

    ... Thromboembolism Aortic Aneurysm More Hispanics and Heart Disease, Stroke Updated:Aug 30,2016 Heart disease is the No. 1 killer for all Americans and stroke is the fifth leading cause of death. Hispanics ...

  19. What Causes a Heart Attack?

    MedlinePlus

    ... After Clinical Trials Links Related Topics Angina Arrhythmia Atherosclerosis Coronary Heart Disease Heart Failure Send a link ... up in the arteries, the condition is called atherosclerosis . The buildup of plaque occurs over many years. ...

  20. Heart Attack Symptoms in Women

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Heart Attack Symptoms in Women Updated:Jan 10,2017 Heart Attack Signs in Women Uncomfortable pressure, squeezing, fullness or ...

  1. Heart Failure Society of America

    MedlinePlus

    ... hfsa.org Events Calendar>> Copyright © 2017 Heart Failure Society of America. All Rights Reserved 2017 Call for ... for Organ Sharing (UNOS) asks the Heart Failure Society of America (HFSA) members to comment on the ...

  2. Diabetes, Heart Disease, and Stroke

    MedlinePlus

    ... Disease, & Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetes, Heart Disease, and Stroke Having diabetes means that ... help to stop. What is the link between diabetes, heart disease, and stroke? Over time, high blood ...

  3. Infant open heart surgery (image)

    MedlinePlus

    During open-heart surgery an incision is made through the breastbone (sternum) while the child is under general anesthesia. ... During open-heart surgery an incision is made through the breastbone (sternum) while the child is under general anesthesia.

  4. Heart Disease and Stroke Statistics

    MedlinePlus

    ... failure on the rise; cardiovascular diseases remain leading killer AHA News: Heart failure projected to increase dramatically, ... failure on the rise; cardiovascular diseases remain leading killer 2017 Statistics At-a-Glance Heart Disease and ...

  5. How Is Heart Disease Diagnosed?

    MedlinePlus

    ... structures inside your chest, such as your heart, lungs, and blood vessels. A chest x ray can reveal signs ... disease and is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of ...

  6. Living with Coronary Heart Disease

    MedlinePlus

    ... disease and is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of ... disease and is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of ...

  7. What Is Coronary Heart Disease?

    MedlinePlus

    ... disease and is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of ... disease and is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of ...

  8. [Heart and Steinert's disease].

    PubMed

    Fayssoil, A; Nardi, O

    2011-08-01

    Myotonic dystrophy type 1 (Steinert disease) is an autosomal dominant disease characterized by myotonia and multiorgan damage. This latter is the most frequent of the adult-onset muscular dystrophies. Heart involvement is often associated, including cardiomyopathies, atrioventricular block, atrial and ventricular arrhythmias.

  9. Sweet & Simple Clay Hearts

    ERIC Educational Resources Information Center

    White, Heather

    2010-01-01

    Nothing pleases parents more than receiving handmade gifts from their children, especially if the gift is in the shape of a heart. Nothing pleases an art teacher more than having a lesson that is easy to follow, teaches basic skills, and enables students to be successful with the activity. In this article, the author describes how to create a…

  10. Heart and vascular services

    MedlinePlus

    ... MedlinePlus GO GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Heart and vascular services URL of this page: //medlineplus.gov/ency/article/ ...

  11. Heart disease and intimacy

    MedlinePlus

    ... hard to talk to your heart doctor about these topics, talk to your primary care provider. If you are depressed, anxious, or afraid, medicine or talk therapy may help. Classes in lifestyle change, stress management, or therapy may help you, family members, and ...

  12. Heart Ed 101

    ERIC Educational Resources Information Center

    Smith, Lynne E.

    2008-01-01

    Cardiovascular disease is the leading cause of death for men and women in the United States. Risk factors and health behaviors combine over time to contribute to the disease process. College communities provide a unique environment for health promotion, risk reduction, and primary intervention. Heart health should be an integral part of college…

  13. Feedback on heart attack.

    PubMed

    Pearce, Lynne

    2016-04-13

    The Royal Brompton & Harefield NHS Foundation Trust in London is the largest heart and lung centre in the UK. This article explores a project carried out by nurses at the trust looking at the experiences of having an acute myocardial infarction, and how patients felt about taking part in a research study.

  14. Exercise and Your Heart.

    ERIC Educational Resources Information Center

    National Heart and Lung Inst. (DHHS/NIH), Bethesda, MD.

    This pamphlet presents information on the effects of physical activity on the heart and practical guidelines for starting and staying on an exercise program. The following topics are discussed: (1) the benefits of getting sufficient exercise; (2) possible risks in exercising compared to benefits; (3) when to seek doctor's advice and prevention of…

  15. Adult Congenital Heart Association

    MedlinePlus

    ... my congenital heart … Read More Let's Talk About Love... BY Kelly DiMaggio Being in love and in a relationship is one of the ... are born they have … Read More Learning to Love the Scar BY Clare Almand I wrote about ...

  16. Be Still My Heart.

    ERIC Educational Resources Information Center

    Barber, Betsy; Ball, Rhonda

    This project description is designed to show how graphing calculators and calculator-based laboratories (CBLs) can be used to explore topics in physics and health sciences. The activities address such topics as respiration, heart rate, and the circulatory system. Teaching notes and calculator instructions are included as are blackline masters. (MM)

  17. Educating the Heart

    ERIC Educational Resources Information Center

    Schwartz, Sherry

    2007-01-01

    Japan's elementary and junior high schools have a formal, nationally mandated moral curriculum called Kokoro-no-kyoiku--education of the heart. Japanese educators include moral growth as an integral part of one's intellectual growth and believe that democratic societies must promote virtuous decision making. Moral education in Japan nurtures the…

  18. About Heart Failure

    MedlinePlus

    ... prescribe an ACE inhibitor  Last, they prescribe a beta-blocker This is what these medicines do to help ... ARBs. This medicine works similar to ACE inhibitors. Beta-blockers:  Protect the heart by slowing down the heartbeat  ...

  19. A call to action: bold ideas from the Minnesota Women's Heart Summit.

    PubMed

    Ali, Nora; Lindquist, Ruth; Boucher, Jackie L; Witt, Dawn; Ambroz, Teresa; Konety, Suma H; Luepker, Russell; Windenburg, Denise; Hayes, Sharonne N

    2012-05-01

    Minnesota has the lowest overall coronary heart disease mortality rate in the United States. Yet disparities between men and women persist with regard to prevention, detection, and treatment. This has led to a gender gap not only in terms of care but also in survival rates. In an effort to better understand and close the gender gap, the Minneapolis Heart Institute, the Minneapolis Heart Institute Foundation, the University of Minnesota, and Mayo Clinic hosted a multidisciplinary Women's Heart Summit in April 2010. The goals of the summit were to stimulate dialogue and devise strategies to eliminate untimely deaths of women from heart disease. Summit participants were asked to contribute suggestions--called "Bold Ideas"--to address sex-based differences in the prevention, detection, and treatment of heart disease. Ideas were categorized according to three themes: educational programming, modifications to the health care system, and government involvement and funding. From these, several solutions emerged: 1) Involve obstetric/gynecologic physicians in providing heart-health education; 2) involve mid-level providers (midwives and other advanced practice women's health care providers) and other health professionals in women's heart health education, and 3) maximize the use of social media and online newsfeeds to raise awareness of heart disease in women. This article summarizes the discussion of the main ideas submitted by summit participants.

  20. The Danish Heart Registry

    PubMed Central

    Özcan, Cengiz; Juel, Knud; Flensted Lassen, Jens; von Kappelgaard, Lene Mia; Mortensen, Poul Erik; Gislason, Gunnar

    2016-01-01

    Aim The Danish Heart Registry (DHR) seeks to monitor nationwide activity and quality of invasive diagnostic and treatment strategies in patients with ischemic heart disease as well as valvular heart disease and to provide data for research. Study population All adult (≥15 years) patients undergoing coronary angiography (CAG), percutaneous coronary intervention (PCI), coronary artery bypass grafting, and heart valve surgery performed across all Danish hospitals were included. Main variables The DHR contains a subset of the data stored in the Eastern and Western Denmark Heart Registries (EDHR and WDHR). For each type of procedure, up to 70 variables are registered in the DHR. Since 2010, the data quality protocol encompasses fulfillment of web-based validation rules of daily-submitted records and yearly approval of the data by the EDHR and WDHR. Descriptive data The data collection on procedure has been complete for PCI and surgery since 2000, and for CAG as of 2006. From 2000 to 2014, the number of CAG, PCI, and surgical procedures changed by 231%, 193%, and 99%, respectively. Until the end of 2014, a total of 357,476 CAG, 131,309 PCI, and 60,831 surgical procedures had been performed, corresponding to 249,445, 100,609, and 55,539 first-time patients, respectively. The DHR generally has a high level of completeness (1–missing) of each procedure (>90%) when compared to the National Patient Registry. Variables important for assessing the quality of care have a high level of completeness for surgery since 2000, and for CAG and PCI since 2010. Conclusion The DHR contains valuable data on cardiac invasive procedures, which makes it an important national monitoring and quality system and at the same time serves as a platform for research projects in the cardiovascular field. PMID:27822091

  1. Effects of exercise training on acclimatization to hypoxia: systemic O2 transport during maximal exercise.

    PubMed

    Favret, Fabrice; Henderson, Kyle K; Richalet, Jean-Paul; Gonzalez, Norberto C

    2003-10-01

    Acclimatization to hypoxia has minimal effect on maximal O2 uptake (Vo2 max). Prolonged hypoxia shows reductions in cardiac output (Q), maximal heart rate (HR-max), myocardial beta-adrenoceptor (beta-AR) density, and chronotropic response to isoproterenol. This study tested the hypothesis that exercise training (ET), which attenuates beta-AR downregulation, would increase HRmax and Q of acclimatization and result in higher Vo2 max. After 3 wk of ET, rats lived at an inspired Po2 of 70 Torr for 10 days (acclimatized trained rats) or remained in normoxia, while both groups continued to train in normoxia. Controls were sedentary acclimatized and nonacclimatized rats. All rats exercised maximally in normoxia and hypoxia (inspired Po2 of 70 Torr). Myocardial beta-AR density and the chronotropic response to isoproterenol were reduced, and myocardial cholinergic receptor density was increased after acclimatization; all of these receptor changes were reversed by ET. Normoxic Vo2 max (in ml.min-1.kg-1) was 95.8 +/- 1.0 in acclimatized trained (n = 6), 87.7 +/- 1.7 in nonacclimatized trained (P < 0.05, n = 6), 74.2 +/- 1.4 in acclimatized sedentary (n = 6, P < 0.05), and 72.5 +/- 1.2 in nonacclimatized sedentary (n = 8; P > 0.05 acclimatized sedentary vs. nonacclimatized sedentary). A similar distribution of Vo2 max values occurred in hypoxic exercise. Q was highest in trained acclimatized and nonacclimatized, intermediate in nonacclimatized sedentary, and lowest in acclimatized sedentary groups. ET preserved Q in acclimatized rats thanks to maintenance of HRmax as well as of maximal stroke volume. Q preservation, coupled with a higher arterial O2 content, resulted in the acclimatized trained rats having the highest convective O2 transport and Vo2 max. These results show that ET attenuates beta-AR downregulation and preserves Q and Vo2 max after acclimatization, and support the idea that beta-AR downregulation partially contributes to the limitation of Vo2 max after

  2. Ventromedial frontal lobe damage disrupts value maximization in humans.

    PubMed

    Camille, Nathalie; Griffiths, Cathryn A; Vo, Khoi; Fellows, Lesley K; Kable, Joseph W

    2011-05-18

    Recent work in neuroeconomics has shown that regions in orbitofrontal and medial prefrontal cortex encode the subjective value of different options during choice. However, these electrophysiological and neuroimaging studies cannot demonstrate whether such signals are necessary for value-maximizing choices. Here we used a paradigm developed in experimental economics to empirically measure and quantify violations of utility theory in humans with damage to the ventromedial frontal lobe (VMF). We show that people with such damage are more likely to make choices that violate the generalized axiom of revealed preference, which is the one necessary and sufficient condition for choices to be consistent with value maximization. These results demonstrate that the VMF plays a critical role in value-maximizing choice.

  3. Maximally symmetric stabilizer MUBs in even prime-power dimensions

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Schultz, Jussi; Toigo, Alessandro

    2017-03-01

    One way to construct a maximal set of mutually unbiased bases (MUBs) in a prime-power dimensional Hilbert space is by means of finite phase-space methods. MUBs obtained in this way are covariant with respect to some subgroup of the group of all affine symplectic phase-space transformations. However, this construction is not canonical: as a consequence, many different choices of covariance subgroups are possible. In particular, when the Hilbert space is 2n dimensional, it is known that covariance with respect to the full group of affine symplectic phase-space transformations can never be achieved. Here we show that in this case there exist two essentially different choices of maximal subgroups admitting covariant MUBs. For both of them, we explicitly construct a family of 2n covariant MUBs. We thus prove that, contrary to the odd dimensional case, maximally covariant MUBs are very far from being unique in even prime-power dimensions.

  4. Evaluation of maximal respiratory pressures in myasthenia gravis. Prognostic value.

    PubMed

    Muñoz Fernández, Carmen; Díez Tejedor, Exuperio; Frank Garcia, Ana; Pino, Jose María; Pérez Conde, Concepción; Barreiro Tella, Pablo

    2004-01-01

    We assess the prognosis of mild forms of myasthenia gravis (MG) by maximal respiratory pressures (MRP) and single fiber electromyography (SFEMG). Fifty MG patients (12 form I, 21 form IIa and 17 form IIb) are valued by MRP [maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP)] and SFEMG, and are followed-up clinically. We have found in form I patients developing form IIa and form IIa worsening to form IIb, MEP and MIP mean relative values significantly lower than the rest. Inversely, IIb form patients improving to IIa form display MIP mean relative values higher than the rest; no difference appears with MEP. A reduction under 50% of fifth-percentile implies clinical deterioration in forms I and IIa, while its surpassing in IIb form suggests a tendency to improvement. No evident differences are found by SFEMG. MRP allow the follow-up of MG patients and could warn us of a clinical prognosis.

  5. Viscosity and density dependence during maximal flow in man.

    PubMed

    Staats, B A; Wilson, T A; Lai-Fook, S J; Rodarte, J R; Hyatt, R E

    1980-02-01

    Maximal expiratory flow curves were obtained from ten healthy subjects white breathing air and three other gas mixtures with different densities and viscosities. From these data, the magnitudes of the dependence of maximal flow on gas density and viscosity were obtained. The scaling laws of fluid mechanics, together with a model for the flow-limiting mechanism, were used to obtain a prediction of the relationship between the density dependence and the viscosity dependence of maximal flow. Although the data for individual subjects were too variable to allow a precise comparison with this prediction, the relationship between the mean density dependence and the mean viscosity dependence of all usbjects agreed with the theoretic prediction. This agreement supports the assumption, which is frequently made, that flow resistance rather than tissue visoelasticity is the dominant contributor to peripheral resistance. Information on the relationships between the pressure drop to the flow-limiting segment and flow, gas density and viscosity, and lung volume were also obtained.

  6. Matching and maximizing with variable-time schedules.

    PubMed Central

    DeCarlo, L T

    1985-01-01

    Pigeons were offered choices between a variable-time schedule that arranged reinforcers throughout the session and a variable-time schedule that arranged reinforcers only when the pigeon was spending time on it. The subjects could maximize the overall rate of reinforcement in this situation by biasing their time allocation towards the latter schedule. This arrangement provides an alternative to concurrent variable-interval variable-ratio schedules for testing whether animals maximize overall rates or match relative rates, and has the advantage of being free of the asymmetrical response requirements present with those schedules. The results were contrary to those predicted by maximizing: The bias it predicts did not appear. PMID:3981085

  7. Fetal Echocardiography/Your Unborn Baby's Heart

    MedlinePlus

    ... in the Young, American Heart Association Overview of congenital heart disease: Congenital heart disease is a problem that occurs with the baby's ... Find answers to common questions about children and heart disease. CHD Personal Stories ... and hope. Popular Articles ...

  8. How Is a Heart Attack Treated?

    MedlinePlus

    ... from the NHLBI on Twitter. How Is a Heart Attack Treated? Early treatment for a heart attack can ... or years after the procedure. Other Treatments for Heart Attack Other treatments for heart attack include: Medicines Medical ...

  9. How Is a Heart Attack Diagnosed?

    MedlinePlus

    ... from the NHLBI on Twitter. How Is a Heart Attack Diagnosed? Your doctor will diagnose a heart attack ... This Content: NEXT >> Featured Video What is a heart attack? 05/22/2014 Describes how a heart attack ...

  10. Heart Failure in South America

    PubMed Central

    Bocchi, Edimar Alcides

    2013-01-01

    Continued assessment of temporal trends in mortality and epidemiology of specific heart failure in South America is needed to provide a scientific basis for rational allocation of the limited health care resources, and strategies to reduce risk and predict the future burden of heart failure. The epidemiology of heart failure in South America was reviewed. Heart failure is the main cause of hospitalization based on available data from approximately 50% of the South American population. The main etiologies of heart failure are ischemic, idiopathic dilated cardiomyopathy, valvular, hypertensive and chagasic etiologies. In endemic areas, Chagas heart disease may be responsible by 41% of the HF cases. Also, heart failure presents high mortality especially in patients with Chagas etiology. Heart failure and etiologies associated with heart failure may be responsible for 6.3% of causes of deaths. Rheumatic fever is the leading cause of valvular heart disease. However, a tendency to reduction of HF mortality due to Chagas heart disease from 1985 to 2006, and reduction in mortality due to HF from 1999 to 2005 were observed in selected states in Brazil. The findings have important public health implications because the allocation of health care resources, and strategies to reduce risk of heart failure should also consider the control of neglected Chagas disease and rheumatic fever in South American countries. PMID:23597301

  11. Facts about Congenital Heart Defects

    MedlinePlus

    ... into the heart, where a doctor can take measurements and pictures, do tests, or repair the problem. Sometimes the heart defect can’t be fully repaired, but these procedures can improve blood flow and the way the heart works. Causes The ...

  12. What Is Heart Valve Disease?

    MedlinePlus

    ... flow properly. Acquired heart valve disease usually involves aortic or mitral valves. Although the valves are normal at first, problems develop over time. Both congenital and acquired heart valve disease can cause stenosis or backflow. Outlook Many people have heart valve ...

  13. Your Heart Failure Healthcare Team

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Your Heart Failure Healthcare Team Updated:Sep 28,2016 Patients with ... to the Terms and Conditions and Privacy Policy Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  14. Warning Signs of Heart Failure

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Warning Signs of Heart Failure Updated:Feb 9,2017 By themselves, any one ... faster. This content was last reviewed April 2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  15. FastStats: Heart Disease

    MedlinePlus

    ... 96 [PDF - 9.8 MB] Death rates for diseases of heart, by sex, race, Hispanic origin, and age Health, United States, 2015, table 22 [ ... causes of death, by sex, race, and Hispanic origin Health, United States, 2015, table ... in Heart Disease and Cancer Mortality Recent Trends in Heart Failure- ...

  16. HEART OF MYTH – HEART OF SCIENCE Part I

    PubMed Central

    Bound Alberti, Fay

    2015-01-01

    This article explores the history and meanings of the heart and its diseases as aspects of the histories of science and emotion. Analyzing the twofold meanings of the heart as both bodily object and cultural symbol, it explores the reasons for the apparent conflict in meanings of the heart of science and the heart of emotion in Western medical culture since the 19th century. In Part I, a case study of the writer, economist, and philosopher Harriet Martineau is used to demonstrate and trace that conflict, while Part II highlights the manifold meanings of the heart both in the past and in the present. PMID:26167117

  17. Non-Heart-Beating Donor Heart Transplantation: Breaking the Taboo

    PubMed Central

    Fatullayev, Javid; Samak, Mostafa; Sabashnikov, Anton; Weymann, Alexander; Mohite, Prashant N.; García-Sáez, Diana; Patil, Nikhil P.; Dohmen, Pascal M.; Popov, Aron-Frederik; Simon, André R.; Zeriouh, Mohamed

    2015-01-01

    Roughly 60% of hearts offered for transplantation are rejected because of organ dysfunction. Moreover, hearts from circulatory-dead patients have long been thought to be non-amenable for transplantation, unlike other organs. However, tentative surgical attempts inspired by the knowledge obtained from preclinical research to recover those hearts have been performed, finally culminating in clinically successful transplants. In this review we sought to address the major concerns in non-heart-beating donor heart transplantation and highlight recently introduced developments to overcome them. PMID:26174972

  18. Beyond heart transplantation: potentials and problems of the shape memory alloy fibers in the treatment of heart failure.

    PubMed

    Kalogerakos, Paris D; Hassoulas, Jannie; Ladopoulos, Vlassis S

    2014-01-01

    Heart failure can be treated with devices that mechanically support the circulation. The improvement of these devices would benefit many patients, especially those refractory to maximal pharmacological treatment and ineligible for heart transplantation. This study examined whether the shape memory alloy (SMA) fibers, which are fibers that contract when electric current flows through them and relax passively when that flow is interrupted, can be wrapped around the failing heart and assist in its pumping action. A band of SMA fibers was wrapped around a silicon cylindrical chamber which simulated a dilated heart and its pumping action was tested in a circulatory mockup. This rudimentary device was innovatively controlled by pulse width modulation. The band was made of only six fibers but yet produced the considerable pressure of 20 mm Hg and a stroke volume of 11.8 ml with modest energy demands. A SMA device could assist a severely failing heart, but there are limiting factors to overcome before designing highly effective devices.

  19. Influence of central obesity in estimating maximal oxygen uptake

    PubMed Central

    de Souza e Silva, Christina Grüne; Franklin, Barry A.; de Araújo, Claudio Gil Soares

    2016-01-01

    OBJECTIVE: To assess the influence of central obesity on the magnitude of the error of estimate of maximal oxygen uptake in maximal cycling exercise testing. METHOD: A total of 1,715 adults (68% men) between 18-91 years of age underwent cardiopulmonary exercise testing using a progressive protocol to volitional fatigue. Subjects were stratified by central obesity into three quartile ranges: Q1, Q2-3 and Q4. Maximal oxygen uptake [mL.(kg.min)-1] was estimated by the attained maximal workload and body weight using gender- and population-specific equations. The error of estimate [mL.(kg.min)-1] and percent error between measured and estimated maximal oxygen uptake values were compared among obesity quartile ranges. RESULTS: The error of estimate and percent error differed (mean ± SD) for men (Q1=1.3±3.7 and 2.0±10.4; Q2-3=0.5±3.1 and -0.5±13.0; and Q4=-0.3±2.8 and -4.5±15.8 (p<0.05)) and for women (Q1=1.6±3.3 and 3.6±10.2; Q2-3=0.4±2.7 and -0.4±11.8; and Q4=-0.9±2.3 and -10.0±22.7 (p<0.05)). CONCLUSION: Central obesity directly influences the magnitude of the error of estimate of maximal oxygen uptake and should be considered when direct expired gas analysis is unavailable. PMID:27982162

  20. Classification of maximally supersymmetric backgrounds in supergravity theories

    NASA Astrophysics Data System (ADS)

    Louis, Jan; Lüst, Severin

    2017-02-01

    We study maximally supersymmetric solutions of all gauged or deformed supergravity theories in D ≥ 3 space-time dimensions. For vanishing background fluxes the space-time background has to be either Minkowski or anti-de Sitter. We derive a simple criterion for the existence of solutions with non-trivial fluxes and determine all supergravities that satisfy it. We show that their solutions coincide with those of the corresponding ungauged theories and conclude that the known list of maximally supersymmetric solutions is exhaustive.

  1. Maximizing the Divergence from a Hierarchical Model of Quantum States

    NASA Astrophysics Data System (ADS)

    Weis, Stephan; Knauf, Andreas; Ay, Nihat; Zhao, Ming-Jing

    2015-03-01

    We study many-party correlations quantified in terms of the Umegaki relative entropy (divergence) from a Gibbs family known as a hierarchical model. We derive these quantities from the maximum-entropy principle which was used earlier to define the closely related irreducible correlation. We point out the differences between quantum states and probability vectors which exist in hierarchical models, in the divergence from a hierarchical model and in local maximizers of this divergence. The differences are, respectively, missing factorization, discontinuity and reduction of uncertainty. We discuss global maximizers of the mutual information of separable qubit states.

  2. Remarks on the information entropy maximization method and extended thermodynamics

    NASA Astrophysics Data System (ADS)

    Eu, Byung Chan

    1998-04-01

    The information entropy maximization method was applied by Jou et al. [J. Phys. A 17, 2799 (1984)] to heat conduction in the past. Advancing this method one more step, Nettleton [J. Chem. Phys. 106, 10311 (1997)] combined the method with a projection operator technique to derive a set of evolution equations for macroscopic variables from the Liouville equation for a simple liquid, and a claim was made that the method provides a statistical mechanical theory basis of irreversible processes and, in particular, of extended thermodynamics which is consistent with the laws of thermodynamics. This line of information entropy maximization method is analyzed from the viewpoint of the laws of thermodynamics in this paper.

  3. Cardiac performance correlates of relative heart ventricle mass in amphibians.

    PubMed

    Kluthe, Gregory J; Hillman, Stanley S

    2013-08-01

    This study used an in situ heart preparation to analyze the power output and stroke work of spontaneously beating hearts of four anurans (Rhinella marina, Lithobates catesbeianus, Xenopus laevis, Pyxicephalus edulis) and three urodeles (Necturus maculosus, Ambystoma tigrinum, Amphiuma tridactylum) that span a representative range of relative ventricle mass (RVM) found in amphibians. Previous research has documented that RVM correlates with dehydration tolerance and maximal aerobic capacity in amphibians. The power output (mW g(-1) ventricle mass) and stroke work (mJ g(-1) ventricle muscle mass) were independent of RVM and were indistinguishable from previously published results for fish and reptiles. RVM was significantly correlated with maximum power output (P max, mW kg(-1) body mass), stroke volume, cardiac output, afterload pressure (P O) at P max, and preload pressure (P I) at P max. P I at P max and P O at P max also correlated very closely with each other. The increases in both P I and P O at maximal power outputs in large hearts suggest that concomitant increases in blood volume and/or increased modulation of vascular compliance either anatomically or via sympathetic tone on the venous vasculature would be necessary to achieve P max in vivo. Hypotheses for variation in RVM and its concomitant increased P max in amphibians are developed.

  4. Effects of cognitive stimulation with a self-modeling video on time to exhaustion while running at maximal aerobic velocity: a pilot study.

    PubMed

    Hagin, Vincent; Gonzales, Benoît R; Groslambert, Alain

    2015-04-01

    This study assessed whether video self-modeling improves running performance and influences the rate of perceived exertion and heart rate response. Twelve men (M age=26.8 yr., SD=6; M body mass index=22.1 kg.m(-2), SD=1) performed a time to exhaustion running test at 100 percent maximal aerobic velocity while focusing on a video self-modeling loop to synchronize their stride. Compared to the control condition, there was a significant increase of time to exhaustion. Perceived exertion was lower also, but there was no significant change in mean heart rate. In conclusion, the video self-modeling used as a pacer apparently increased endurance by decreasing perceived exertion without affecting the heart rate.

  5. Electrophysiological Remodeling in Heart Failure

    PubMed Central

    Wang, Yanggan; Hill, Joseph A.

    2010-01-01

    Heart failure affects nearly 6 million Americans, with a half-million new cases emerging each year. Whereas up to 50% of heart failure patients die of arrhythmia, the diverse mechanisms underlying heart failure-associated arrhythmia are poorly understood. As a consequence, effectiveness of antiarrhythmic pharmacotherapy remains elusive. Here, we review recent advances in our understanding of heart failure-associated molecular events impacting the electrical function of the myocardium. We approach this from an anatomical standpoint, summarizing recent insights gleaned from pre-clinical models and discussing their relevance to human heart failure. PMID:20096285

  6. Different types of compression clothing do not increase sub-maximal and maximal endurance performance in well-trained athletes.

    PubMed

    Sperlich, Billy; Haegele, Matthias; Achtzehn, Silvia; Linville, John; Holmberg, Hans-Christer; Mester, Joachim

    2010-04-01

    Three textiles with increasing compressive surface were compared with non-compressive conventional clothing on physiological and perceptual variables during sub-maximal and maximal running. Fifteen well-trained endurance athletes (mean+/-s: age 27.1+/-4.8 years, VO(2max) 63.7+/-4.9 ml x min(-1) x kg(-1)) performed four sub-maximal (approximately 70% VO(2max)) and maximal tests with and without different compression stockings, tights, and whole-body compression suits. Arterial lactate concentration, oxygen saturation and partial pressure, pH, oxygen uptake, and ratings of muscle soreness were recorded before, during, and after all tests. In addition, we assessed time to exhaustion. Sub-maximal (P=0.22) and maximal oxygen uptake (P=0.26), arterial lactate concentration (P=0.16; 0.20), pH (P=0.23; 0.46), oxygen saturation (P=0.13; 0.26), and oxygen partial pressure (P=0.09; 0.20) did not differ between the types of clothing (effect sizes=0.00-0.45). Ratings of perceived exertion (P=0.10; 0.15), muscle soreness (P=0.09; 0.10) and time to exhaustion (P=0.16) were also unaffected by the different clothing (effect sizes=0.28-0.85). This was the first study to evaluate the effect on endurance performance of different types of compression clothing with increasing amounts of compressive surface. Overall, there were no performance benefits when using the compression garments.

  7. Heart Imaging System

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Johnson Space Flight Center's device to test astronauts' heart function in microgravity has led to the MultiWire Gamma Camera, which images heart conditions six times faster than conventional devices. Dr. Jeffrey Lacy, who developed the technology as a NASA researcher, later formed Proportional Technologies, Inc. to develop a commercially viable process that would enable use of Tantalum-178 (Ta-178), a radio-pharmaceutical. His company supplies the generator for the radioactive Ta-178 to Xenos Medical Systems, which markets the camera. Ta-178 can only be optimally imaged with the camera. Because the body is subjected to it for only nine minutes, the radiation dose is significantly reduced and the technique can be used more frequently. Ta-178 also enables the camera to be used on pediatric patients who are rarely studied with conventional isotopes because of the high radiation dosage.

  8. Anemia and heart failure.

    PubMed

    O'Meara, Eileen; Murphy, Clare; McMurray, John J V

    2004-12-01

    Over the past few years, anemia has emerged as a powerful independent predictor of adverse outcomes in chronic heart failure (CHF). It affects up to 50% of patients with CHF, depending on the definition of anemia used and on the population studied. Even small reductions in hemoglobin are associated with worse outcome. However, the causes of anemia in CHF remain unclear, although impairment of renal function and inflammatory cytokines are proposed mechanisms. Both may act through impairment of the synthesis or action of erythropoietin. Preliminary studies have demonstrated improvement in symptoms, exercise tolerance, quality of life, and reductions in hospitalizations when patients with severe CHF were treated with erythropoietin. The benefits and the potential risks of such therapies will be further addressed in upcoming larger randomized trials. The recent interest in anemia reflects a new perspective in heart failure therapy, focusing on non-cardiovascular comorbidities.

  9. Maximizing the Online Learning Experience: Suggestions for Educators and Students

    ERIC Educational Resources Information Center

    Cicco, Gina

    2011-01-01

    This article will discuss ways of maximizing the online course experience for teachers- and counselors-in-training. The widespread popularity of online instruction makes it a necessary learning experience for future teachers and counselors (Ash, 2011). New teachers and counselors take on the responsibility of preparing their students for real-life…

  10. Maximizing Thermal Efficiency and Optimizing Energy Management (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

  11. Matching Pupils and Teachers to Maximize Expected Outcomes.

    ERIC Educational Resources Information Center

    Ward, Joe H., Jr.; And Others

    To achieve a good teacher-pupil match, it is necessary (1) to predict the learning outcomes that will result when each student is instructed by each teacher, (2) to use the predicted performance to compute an Optimality Index for each teacher-pupil combination to indicate the quality of each combination toward maximizing learning for all students,…

  12. On Adaptation, Maximization, and Reinforcement Learning among Cognitive Strategies

    ERIC Educational Resources Information Center

    Erev, Ido; Barron, Greg

    2005-01-01

    Analysis of binary choice behavior in iterated tasks with immediate feedback reveals robust deviations from maximization that can be described as indications of 3 effects: (a) a payoff variability effect, in which high payoff variability seems to move choice behavior toward random choice; (b) underweighting of rare events, in which alternatives…

  13. Optoelectronic plethysmography compared to spirometry during maximal exercise.

    PubMed

    Layton, Aimee M; Moran, Sienna L; Garber, Carol Ewing; Armstrong, Hilary F; Basner, Robert C; Thomashow, Byron M; Bartels, Matthew N

    2013-01-15

    The purpose of this study was to compare simultaneous measurements of tidal volume (Vt) by optoelectronic plethysmography (OEP) and spirometry during a maximal cycling exercise test to quantify possible differences between methods. Vt measured simultaneously by OEP and spirometry was collected during a maximal exercise test in thirty healthy participants. The two methods were compared by linear regression and Bland-Altman analysis at submaximal and maximal exercise. The average difference between the two methods and the mean percentage discrepancy were calculated. Submaximal exercise (SM) and maximal exercise (M) Vt measured by OEP and spirometry had very good correlation, SM R=0.963 (p<0.001), M R=0.982 (p<0.001) and high degree of common variance, SM R(2)=0.928, M R(2)=0.983. Bland-Altman analysis demonstrated that during SM, OEP could measure exercise Vt as much as 0.134 L above and -0.025 L below that of spirometry. OEP could measure exercise Vt as much as 0.188 L above and -0.017 L below that of spirometry. The discrepancy between measurements was -2.0 ± 7.2% at SM and -2.4 ± 3.9% at M. In conclusion, Vt measurements at during exercise by OEP and spirometry are closely correlated and the difference between measurements was insignificant.

  14. Fertilizer placement to maximize nitrogen use by fescue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The method of fertilizer nitrogen(N) application can affect N uptake in tall fescue and therefore its yield and quality. Subsurface-banding (knife) of fertilizer maximizes fescue N uptake in the poorly-drained clay–pan soils of southeastern Kansas. This study was conducted to determine if knifed N r...

  15. Curriculum and Testing Strategies to Maximize Special Education STAAR Achievement

    ERIC Educational Resources Information Center

    Johnson, William L.; Johnson, Annabel M.; Johnson, Jared W.

    2015-01-01

    This document is from a presentation at the 2015 annual conference of the Science Teachers Association of Texas (STAT). The two sessions (each listed as feature sessions at the state conference) examined classroom strategies the presenter used in his chemistry classes to maximize Texas end-of-course chemistry test scores for his special population…

  16. Using Debate to Maximize Learning Potential: A Case Study

    ERIC Educational Resources Information Center

    Firmin, Michael W.; Vaughn, Aaron; Dye, Amanda

    2007-01-01

    Following a review of the literature, an educational case study is provided for the benefit of faculty preparing college courses. In particular, we provide a transcribed debate utilized in a General Psychology course as a best practice example of how to craft a debate which maximizes student learning. The work is presented as a model for the…

  17. Modifying Softball for Maximizing Learning Outcomes in Physical Education

    ERIC Educational Resources Information Center

    Brian, Ali; Ward, Phillip; Goodway, Jacqueline D.; Sutherland, Sue

    2014-01-01

    Softball is taught in many physical education programs throughout the United States. This article describes modifications that maximize learning outcomes and that address the National Standards and safety recommendations. The modifications focus on tasks and equipment, developmentally appropriate motor-skill acquisition, increasing number of…

  18. Maximal regularity for perturbed integral equations on periodic Lebesgue spaces

    NASA Astrophysics Data System (ADS)

    Lizama, Carlos; Poblete, Verónica

    2008-12-01

    We characterize the maximal regularity of periodic solutions for an additive perturbed integral equation with infinite delay in the vector-valued Lebesgue spaces. Our method is based on operator-valued Fourier multipliers. We also study resonances, characterizing the existence of solutions in terms of a compatibility condition on the forcing term.

  19. Apportioning Program Evaluation Resources to Maximize Information Yield.

    ERIC Educational Resources Information Center

    Sadler, D. Royce

    1982-01-01

    Not all data for a program evaluation may be equally valuable, and costs of collection may vary when using several methods to obtain data from several sources. An approach to maximize information yield for a fixed, limited budget using a mathematical technique known as linear programming is described and generalized. (Author/CM)

  20. Formulation of Maximized Weighted Averages in URTURIP Technique

    DTIC Science & Technology

    2001-10-25

    Formulation of Maximized Weighted Averages in URTURIP Technique Bruno Migeon, Philippe Deforge, Pierre Marché Laboratoire Vision et Robotique ...Organization Name(s) and Address(es) Laboratoire Vision et Robotique 63, avenue de Lattre de Tassigny, 18020 Bourges Cedex - France Performing Organization

  1. A Maximal Flow Approach to Dynamic Routing in Communication Networks,

    DTIC Science & Technology

    1980-05-01

    of nodes. In Appendix B we provide a computer program in Fortran for finding the maximal flow in these networks, based on the algorithm of Edmons and... Edmons and Karp is implemented by a Fortran Subroutine called MAXFL. The algorithm finds the shortest path between source and destination on which an

  2. Maximizing the Benefits of an Administrative Internship: Some Practical Advice.

    ERIC Educational Resources Information Center

    Oldfield, Kenneth; Ayers, Nancy

    Recommendations to help student interns in administrative positions maximize their educational opportunities vis-a-vis the "real world" and to also help them avoid certain placement-associated problems. The suggestions may be helpful to both new and established internship directors as well. Attention is focused on governmental administrative…

  3. Maximizing grain sorghum water use efficiency under deficit irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development and evaluation of sustainable and efficient irrigation strategies is a priority for producers faced with water shortages resulting from aquifer depletion, reduced base flows, and reallocation of water to non-agricultural sectors. Under a limited water supply, yield maximization may not b...

  4. Maximizing Access, Equity, and Inclusion in General and Special Education

    ERIC Educational Resources Information Center

    Obiakor, Festus E.

    2011-01-01

    The goal of any educational program is to help its students to maximize their fullest potential in inclusive environments. For many students with disabilities, having an inclusive environment seems to be an ideal policy. Ironically, this policy continues to be debatable and controversial. Sometimes, the controversy or debate dominates the real…

  5. Optimal technique for maximal forward rotating vaults in men's gymnastics.

    PubMed

    Hiley, Michael J; Jackson, Monique I; Yeadon, Maurice R

    2015-08-01

    In vaulting a gymnast must generate sufficient linear and angular momentum during the approach and table contact to complete the rotational requirements in the post-flight phase. This study investigated the optimization of table touchdown conditions and table contact technique for the maximization of rotation potential for forwards rotating vaults. A planar seven-segment torque-driven computer simulation model of the contact phase in vaulting was evaluated by varying joint torque activation time histories to match three performances of a handspring double somersault vault by an elite gymnast. The closest matching simulation was used as a starting point to maximize post-flight rotation potential (the product of angular momentum and flight time) for a forwards rotating vault. It was found that the maximized rotation potential was sufficient to produce a handspring double piked somersault vault. The corresponding optimal touchdown configuration exhibited hip flexion in contrast to the hyperextended configuration required for maximal height. Increasing touchdown velocity and angular momentum lead to additional post-flight rotation potential. By increasing the horizontal velocity at table touchdown, within limits obtained from recorded performances, the handspring double somersault tucked with one and a half twists, and the handspring triple somersault tucked became theoretically possible.

  6. Maximizing plant density affects broccoli yield and quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased demand for fresh market bunch broccoli (Brassica oleracea L. var. italica) has led to increased production along the United States east coast. Maximizing broccoli yields is a primary concern for quickly expanding southeastern commercial markets. This broccoli plant density study was carr...

  7. Mentoring as Professional Development for Novice Entrepreneurs: Maximizing the Learning

    ERIC Educational Resources Information Center

    St-Jean, Etienne

    2012-01-01

    Mentoring can be seen as relevant if not essential in the continuing professional development of entrepreneurs. In the present study, we seek to understand how to maximize the learning that occurs through the mentoring process. To achieve this, we consider various elements that the literature suggested are associated with successful mentoring and…

  8. Emotional Control and Instructional Effectiveness: Maximizing a Timeout

    ERIC Educational Resources Information Center

    Andrews, Staci R.

    2015-01-01

    This article provides recommendations for best practices for basketball coaches to maximize the instructional effectiveness of a timeout during competition. Practical applications are derived from research findings linking emotional intelligence to effective coaching behaviors. Additionally, recommendations are based on the implications of the…

  9. How to Maximize Learning for Gifted Math Students

    ERIC Educational Resources Information Center

    Chamberlin, Scott A.

    2008-01-01

    Having a gifted math or science student in the family or classroom is a fascination as well as a significant challenge and responsibility for many parents and teachers. In order to help maximize student learning, several questions need to be asked. What should be the role of technology? How well do traditional schools serve gifted students? What…

  10. Nursing Students' Awareness and Intentional Maximization of Their Learning Styles

    ERIC Educational Resources Information Center

    Mayfield, Linda Riggs

    2012-01-01

    This small, descriptive, pilot study addressed survey data from four levels of nursing students who had been taught to maximize their learning styles in a first-semester freshman success skills course. Bandura's Agency Theory supports the design. The hypothesis was that without reinforcing instruction, the students' recall and application of that…

  11. The Profit-Maximizing Firm: Old Wine in New Bottles.

    ERIC Educational Resources Information Center

    Felder, Joseph

    1990-01-01

    Explains and illustrates a simplified use of graphical analysis for analyzing the profit-maximizing firm. Believes that graphical analysis helps college students gain a deeper understanding of marginalism and an increased ability to formulate economic problems in marginalist terms. (DB)

  12. Maximally entangled mixed-state generation via local operations

    SciTech Connect

    Aiello, A.; Puentes, G.; Voigt, D.; Woerdman, J. P.

    2007-06-15

    We present a general theoretical method to generate maximally entangled mixed states of a pair of photons initially prepared in the singlet polarization state. This method requires only local operations upon a single photon of the pair and exploits spatial degrees of freedom to induce decoherence. We report also experimental confirmation of these theoretical results.

  13. A Method for Maximizing Split-Half Reliability Coefficients

    ERIC Educational Resources Information Center

    Callender, John C.; Osburn, H. G.

    1977-01-01

    An efficient algorithm for maximizing split-half reliability coefficients is described. Coefficients derived by the algorithm were found to be generally larger than odd-even split-half coefficients or other internal consistency measures and nearly as large as the largest split half coefficients. MSPLIT, Odd-Even, and Kuder-Richardson-20…

  14. Hardy-Littlewood maximal operator in generalized grand Lebesgue spaces

    NASA Astrophysics Data System (ADS)

    Umarkhadzhiev, Salaudin M.

    2014-12-01

    We obtain sufficient conditions and necessary conditions for the maximal operator to be bounded in the generalized grand Lebesgue space on an open set Ω ∈ Rn which is not necessarily bounded. The sufficient conditions coincide with necessary conditions for instance in the case where Ω is bounded and the standard definition of the grand space is used.

  15. Teacher Praise: Maximizing the Motivational Impact. Teaching Strategies.

    ERIC Educational Resources Information Center

    McVey, Mary D.

    2001-01-01

    Recognizes the influence of praise on human behavior, and provides specific suggestions on how to maximize the positive effects of praise when intended as positive reinforcement. Examines contingency, specificity, and selectivity aspects of praise. Cautions teachers to avoid the controlling effects of praise and the possibility that praise may…

  16. Quantum state space as a maximal consistent set

    NASA Astrophysics Data System (ADS)

    Tabia, Gelo Noel

    2012-02-01

    Measurement statistics in quantum theory are obtained from the Born rule and the uniqueness of the probability measure it assigns through quantum states is guaranteed by Gleason's theorem. Thus, a possible systematic way of exploring the geometry of quantum state space expresses quantum states in terms of outcome probabilities of a symmetric informationally complete measurement. This specific choice for representing quantum states is motivated by how the associated probability space provides a natural venue for characterizing the set of quantum states as a geometric construct called a maximal consistent set. We define the conditions for consistency and maximality of a set, provide some examples of maximal consistent sets and attempt to deduce the steps for building up a maximal consistent set of probability distributions equivalent to Hilbert space. In particular, we demonstrate how the reconstruction procedure works for qutrits and observe how it reveals an elegant underlying symmetry among five SIC-POVMs and a complete set of mutually unbiased bases, known in finite affine geometry as the Hesse configuration.

  17. Dextroposition of the Heart

    DTIC Science & Technology

    2007-10-01

    Segmental Analysis A. Location of the Atria Determination of the orientation of the atria is the first step in segmental analysis. A universal rule ...cardiac MRI (Fig. 1B) confirm situs solitus. B. Location of the Ventricles The primitive heart tube of early embryology develops a rightward...The valves exist, as a general rule , in concordance with their associated ventricles. In our patient, the “technically-limited” echocardiography

  18. Heart of Darkness

    PubMed Central

    2016-01-01

    Abstract Significant literature has an impact on the reader. Reading the novella Heart of Darkness by Joseph Conrad as a young boy rose emotions comparable to those I felt when losing a patient after percutaneous nephrolithotomy (PCNL) as a grown up. The case of a 37-year-old woman with bilateral staghorn and a fatal outcome after PCNL is presented and alternatives are discussed. PMID:27868094

  19. Straight from the Heart

    ERIC Educational Resources Information Center

    Jonell, Lynne

    2010-01-01

    Every adult who reads to a child has seen what happens when a book speaks. For a time, the book becomes the child's beloved friend. It is asked for repeatedly and learned by heart. But books do more than speak to a child. Children use books to speak to adults. If one wants to understand a child's deepest emotions, take a look at the books they…

  20. Broken Heart Syndrome

    PubMed Central

    Therkleson, Tessa; Stronach, Shona

    2015-01-01

    This case describes a combination external treatment for “Broken Heart Syndrome” that includes a lavender footbath, massage using moor extract, and oxalis ointment to the abdomen applied by an Anthroposophic nurse for a specific personality type. Lavender footbaths have been used since ancient times for relaxation and calming, while moor extract has been used medicinally in Europe since the middle ages for warmth and environmental protection. Rhythmical massage using moor extract and oxalis ointment poultice to the abdomen are part of the tradition of Anthroposophic nursing when managing stress induced by emotional and physical trauma. An elderly lady with specific characteristics diagnosed as Broken Heart Syndrome received one treatment a week for 4 weeks given by an Anthroposophic nurse at an integrative medical center. Between treatments, education was given to enable self-treatment in the home. The nursing treatments, each using lavender footbaths, moor extract massage, and oxalis ointment poultice to the abdomen, proved very effect, and no negative effects were reported. External applications need to be considered by nurses caring for specific personality types with Broken Heart Syndrome. PMID:25673580

  1. Rethinking Heart Failure

    PubMed Central

    Fürstenwerth, Hauke

    2012-01-01

    An increasing body of clinical observations and experimental evidence suggests that cardiac dysfunction results from autonomic dysregulation of the contractile output of the heart. Excessive activation of the sympathetic nervous system and a decrease in parasympathetic tone are associated with increased mortality. Elevated levels of circulating catecholamines closely correlate with the severity and poor prognosis in heart failure. Sympathetic over-stimulation causes increased levels of catecholamines, which induce excessive aerobic metabolism leading to excessive cardiac oxygen consumption. Resulting impaired mitochondrial function causes acidosis, which results in reduction in blood flow by impairment of contractility. To the extent that the excessive aerobic metabolism resulting from adrenergic stimulation comes to a halt the energy deficit has to be compensated for by anaerobic metabolism. Glucose and glycogen become the essential nutrients. Beta-adrenergic blockade is used successfully to decrease hyperadrenergic drive. Neurohumoral antagonists block adrenergic over-stimulation but do not provide the heart with fuel for compensatory anaerobic metabolism. The endogenous hormone ouabain reduces catecholamine levels in healthy volunteers, promotes the secretion of insulin, induces release of acetylcholine from synaptosomes and potentiates the stimulation of glucose metabolism by insulin and acetylcholine. Ouabain stimulates glycogen synthesis and increases lactate utilisation by the myocardium. Decades of clinical experience with ouabain confirm the cardioprotective effects of this endogenous hormone. The so far neglected sympatholytic and vagotonic effects of ouabain on myocardial metabolism clearly make a clinical re-evaluation of this endogenous hormone necessary. Clinical studies with ouabain that correspond to current standards are warranted.

  2. Rejuvenating the senescent heart

    PubMed Central

    Nguyen, Nathalie; Sussman, Mark A.

    2015-01-01

    Purpose of review The purpose of this review is to provide an update on the cardiac stem cell field with an emphasis on aging and to suggest some relevant strategies directed toward rejuvenation of the senescent heart. Recent findings Stem cells were long considered as a fountain of youth and were assumed to be equipped against any form of aging effect. However, it is now clear that stem cells suffer the consequences of aging as well. With the discovery that cardiac stem cells reside in the heart comes the question whether these cells are also impaired upon aging. As cardiac stem cell properties are also altered with age, autologous stem cell-based therapy to treat heart failure will benefit from new improved strategies. Summary With the goal to improve stem cell properties that are impaired upon aging, some strategies are highlighted. Genetic modification of adult human cardiac progenitor cells prior to autologous stem cell-based therapy, delivery of the next generation of stem cells such as CardioChimeras and CardioClusters, and improvement of the myocardial environment with rejuvenating factors constitute some of the possibilities and are discussed in more detail in this review. PMID:25760821

  3. Maximal intermittent handgrip strategy: design and evaluation of an exercise protocol and a grip tool

    PubMed Central

    Bentley, Danielle Christine; Thomas, Scott Gordon

    2016-01-01

    Handgrip (HG) exercise has been prescribed as a lifestyle intervention to successfully reduce resting blood pressure (BP) among heterogeneous groups of participants. Current HG protocols have limited accessibility due to complicated exercise prescriptions and sophisticated required equipment. Therefore, this research describes the design and evaluation of the maximal intermittent (MINT) HG exercise strategy, consisting of both a novel exercise protocol (32×5 seconds maximal grip squeezes separated by 5 seconds of rest between sets) and an original grip tool. This research was a multistep progressive design that included 51 postmenopausal women as participants in three separate research studies. Part 1 of this research focuses on the MINT exercise protocol. A literature-informed rationale for the design of the protocol is described. This includes exercise intensity, work-to-rest ratio, and total exercise duration with reference to the unique physiology (mechanoreflex and metaboreflex) of postmenopausal women. Subsequent experimental analyses of acute responses to the MINT protocol revealed that women produced 50% of their maximum grip force with moderate cardiovascular responses (increases of systolic BP: 41.6 mmHg, diastolic BP: 20.1 mmHg, heart rate: 35.1 bpm) that remained far below the thresholds of concern identified by the American College of Sports Medicine. Part 2 of this research describes the creation of a novel grip tool, beginning with a mixed-methods assessment of participant opinions regarding two distinct in-laboratory grip tools, leading to the creation of four prototype MINT tools. Structured focus groups revealed a strong preference for MINT prototype 1 for all tool design features, including color, shape, size, and foam grip. Collectively, the result of this multistep research is a novel HG exercise strategy with enhanced accessibility by being easy to understand and simple to execute. The long-term training effectiveness of MINT as an exercise

  4. Cardiac function and myocardial perfusion immediately following maximal treadmill exercise inside the MRI room

    PubMed Central

    Jekic, Mihaela; Foster, Eric L; Ballinger, Michelle R; Raman, Subha V; Simonetti, Orlando P

    2008-01-01

    Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR. It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed. PMID:18272005

  5. Reproducibility of incremental maximal cycle ergometer testing in patients with restrictive lung disease.

    PubMed Central

    Marciniuk, D. D.; Watts, R. E.; Gallagher, C. G.

    1993-01-01

    BACKGROUND--Exercise testing has become an important tool in the diagnosis and treatment of restrictive lung disease. The reproducibility of variables measured during exercise testing was examined in subjects with stable restrictive lung disease. METHODS--Six subjects, who had never previously undergone exercise testing, each underwent three maximal incremental exercise studies on a bicycle ergometer conducted during a 28 day period. RESULTS--Data collected at rest, before exercise, were not significantly different during the three study days. Comparison of results at the end of the exercise tests from the three studies also revealed no evidence of a significant learning effect. Reproducibility of exercise performance by subjects was assessed by the coefficient of variation. The mean within subject coefficient of variation at the end of the exercise tests was 5.6% for work rate, 7.9% for exercise duration, and 9.5% for dyspnoea. The mean within subject coefficient of variation obtained at the end of the exercise tests was 5.3% for oxygen uptake (VO2), 2.5% for oxygen saturation (SaO2), 4.0% for heart rate (HR), 5.5% for minute ventilation (VE), 5.8% for respiratory frequency (f), and 4.6% for tidal volume (VT). The mean within subject coefficient of variation at 40% and 70% of maximal work rates for VO2 was 5.7% and 5.6% respectively, for SaO2 1.3% and 1.5%, for HR 4.8% and 4.0%, for VE 6.3% and 6.6%, for f 10.1% and 7.8%, and for VT 6.0% and 4.5%. CONCLUSIONS--Variables measured during clinical exercise testing in subjects with restrictive lung disease are highly reproducible. No significant learning effect was found on repeated testing in subjects who had never previously undergone exercise testing. PMID:8236071

  6. Twin-sibling study and meta-analysis on the heritability of maximal oxygen consumption

    PubMed Central

    Nederend, Ineke; Hudziak, James J.; Bartels, Meike; de Geus, Eco J. C.

    2016-01-01

    Large individual differences exist in aerobic fitness in childhood and adolescence, but the relative contribution of genetic factors to this variation remains to be established. In a sample of adolescent twins and siblings (n = 479), heart rate (HR) and maximal oxygen uptake (V̇o2max) were recorded during the climax of a graded maximal exercise test. In addition, V̇o2max was predicted in two graded submaximal exercise tests on the cycle ergometer and the treadmill, using extrapolation of the HR/V̇o2 curve to the predicted HRmax. Heritability estimates for measured V̇o2max were 60% in ml/min and 55% for V̇o2max in ml·min−1·kg−1. Phenotypic correlations between measured V̇o2max and predicted V̇o2max from either submaximal treadmill or cycle ergometer tests were modest (0.57 < r < 0.70), in part because of the poor agreement between predicted and actual HRmax. The majority of this correlation was explained by genetic factors; therefore, the submaximal exercise tests still led to very comparable estimates of heritability of V̇o2max. To arrive at a robust estimate for the heritability of V̇o2max in children to young adults, a sample size weighted meta-analysis was performed on all extant twin and sibling studies in this age range. Eight studies, including the current study, were meta-analyzed and resulted in a weighted heritability estimate of 59% (ml/min) and 72% (ml·min−1·kg−1) for V̇o2max. Taken together, the twin-sibling study and meta-analyses showed that from childhood to early adulthood genetic factors determine more than half of the individual differences in V̇o2max. PMID:26787216

  7. Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes.

    PubMed

    Park, Saejong; Kim, Jong Kyung; Choi, Hyun Min; Kim, Hyun Gook; Beekley, Matthew D; Nho, Hosung

    2010-07-01

    Walk training with blood flow occlusion (OCC-walk) leads to muscle hypertrophy; however, cardiorespiratory endurance in response to OCC-walk is unknown. Ischemia enhances the adaptation to endurance training such as increased maximal oxygen uptake (VO₂(max)) and muscle glycogen content. Thus, we investigated the effects of an OCC-walk on cardiorespiratory endurance, anaerobic power, and muscle strength in elite athletes. College basketball players participated in walk training with (n = 7) and without (n = 5) blood flow occlusion. Five sets of a 3-min walk (4-6 km/h at 5% grade) and a 1-min rest between the walks were performed twice a day, 6 days a week for 2 weeks. Two-way ANOVA with repeated measures (groups x time) was utilized (P < 0.05). Interactions were found in VO₂(max) (P = 0.011) and maximal minute ventilation (VE(max); P = 0.019). VO₂(max) (11.6%) and VE(max) (10.6%) were increased following the OCC-walk. For the cardiovascular adaptations of the OCC-walk, hemodynamic parameters such as stroke volume (SV) and heart rate (HR) at rest and during OCC-walk were compared between the first and the last OCC-walk sessions. Although no change in hemodynamics was found at rest, during the last OCC-walk session SV was increased in all five sets (21.4%) and HR was decreased in the third (12.3%) and fifth (15.0%) sets. With anaerobic power an interaction was found in anaerobic capacity (P = 0.038) but not in peak power. Anaerobic capacity (2.5%) was increased following the OCC-walk. No interaction was found in muscle strength. In conclusion, the 2-week OCC-walk significantly increases VO₂(max) and VE(max) in athletes. The OCC-walk training might be used in the rehabilitation for athletes who intend to maintain or improve endurance.

  8. Twin-sibling study and meta-analysis on the heritability of maximal oxygen consumption.

    PubMed

    Schutte, Nienke M; Nederend, Ineke; Hudziak, James J; Bartels, Meike; de Geus, Eco J C

    2016-03-01

    Large individual differences exist in aerobic fitness in childhood and adolescence, but the relative contribution of genetic factors to this variation remains to be established. In a sample of adolescent twins and siblings (n = 479), heart rate (HR) and maximal oxygen uptake (V̇o2max) were recorded during the climax of a graded maximal exercise test. In addition, V̇o2max was predicted in two graded submaximal exercise tests on the cycle ergometer and the treadmill, using extrapolation of the HR/V̇o2 curve to the predicted HRmax. Heritability estimates for measured V̇o2max were 60% in ml/min and 55% for V̇o2max in ml·min(-1)·kg(-1). Phenotypic correlations between measured V̇o2max and predicted V̇o2max from either submaximal treadmill or cycle ergometer tests were modest (0.57 < r < 0.70), in part because of the poor agreement between predicted and actual HRmax. The majority of this correlation was explained by genetic factors; therefore, the submaximal exercise tests still led to very comparable estimates of heritability of V̇o2max. To arrive at a robust estimate for the heritability of V̇o2max in children to young adults, a sample size weighted meta-analysis was performed on all extant twin and sibling studies in this age range. Eight studies, including the current study, were meta-analyzed and resulted in a weighted heritability estimate of 59% (ml/min) and 72% (ml·min(-1)·kg(-1)) for V̇o2max. Taken together, the twin-sibling study and meta-analyses showed that from childhood to early adulthood genetic factors determine more than half of the individual differences in V̇o2max.

  9. Maximal intermittent handgrip strategy: design and evaluation of an exercise protocol and a grip tool.

    PubMed

    Bentley, Danielle Christine; Thomas, Scott Gordon

    2016-01-01

    Handgrip (HG) exercise has been prescribed as a lifestyle intervention to successfully reduce resting blood pressure (BP) among heterogeneous groups of participants. Current HG protocols have limited accessibility due to complicated exercise prescriptions and sophisticated required equipment. Therefore, this research describes the design and evaluation of the maximal intermittent (MINT) HG exercise strategy, consisting of both a novel exercise protocol (32×5 seconds maximal grip squeezes separated by 5 seconds of rest between sets) and an original grip tool. This research was a multistep progressive design that included 51 postmenopausal women as participants in three separate research studies. Part 1 of this research focuses on the MINT exercise protocol. A literature-informed rationale for the design of the protocol is described. This includes exercise intensity, work-to-rest ratio, and total exercise duration with reference to the unique physiology (mechanoreflex and metaboreflex) of postmenopausal women. Subsequent experimental analyses of acute responses to the MINT protocol revealed that women produced 50% of their maximum grip force with moderate cardiovascular responses (increases of systolic BP: 41.6 mmHg, diastolic BP: 20.1 mmHg, heart rate: 35.1 bpm) that remained far below the thresholds of concern identified by the American College of Sports Medicine. Part 2 of this research describes the creation of a novel grip tool, beginning with a mixed-methods assessment of participant opinions regarding two distinct in-laboratory grip tools, leading to the creation of four prototype MINT tools. Structured focus groups revealed a strong preference for MINT prototype 1 for all tool design features, including color, shape, size, and foam grip. Collectively, the result of this multistep research is a novel HG exercise strategy with enhanced accessibility by being easy to understand and simple to execute. The long-term training effectiveness of MINT as an exercise

  10. Effects of acute inhalation of albuterol on submaximal and maximal VO2 and blood lactate.

    PubMed

    Fleck, S J; Lucia, A; Storms, W W; Wallach, J M; Vint, P F; Zimmerman, S D

    1993-07-01

    The acute effects of inhaled albuterol, a selective beta-2 adrenergic agonist, on measures of endurance cycling performance and pulmonary function were assessed in 21 competitive road cyclists. A 5 step methacholine challenge revealed all cyclists to be non-asthmatic. Albuterol (A) total dose 360 micrograms or a saline placebo (P) was administered by inhaler, in 4 metered doses of 90 micrograms each, 15 minutes before cycle ergometry exercise. Heart rate, whole blood lactate, perceived exertion and VO2 were determined at the submaximal workloads of 150, 200, 225, 250, 275, 300 watts and at max. Pulmonary function tests determining forced vital capacity, forced expiratory volume during the first second of expiration, forced mid-expiratory flow and maximal voluntary ventilation were performed prior to and 10 minutes after inhalation; and 5, 10 and 15 minutes after termination of the exercise protocol. Heart rate was significantly greater during the A compared to the P treatment at 200 (150.8 +/- 2.5 vs 146.7 +/- 2.8 beats per minute), 225 (159.7 +/- 2.4 vs 154.6 +/- 2.7 beats per minute) and 250 watts (166.9 +/- 2.4 vs 164.4 +/- 2.6 beats per minute). Whole blood lactate was significantly greater during the A compared to the P treatment at 275 watts (4.7 +/- 0.3 vs 4.2 +/- 0.4 mmol.l-1). No other significant differences were found between the 2 treatments at any time point. These data indicate that the acute effect of albuterol inhalation at twice the recommended dosage has no positive effect on endurance performance measures or pulmonary function in athletes who are not asthmatic.

  11. Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training.

    PubMed

    Bonne, Thomas C; Doucende, Gregory; Flück, Daniela; Jacobs, Robert A; Nordsborg, Nikolai B; Robach, Paul; Walther, Guillaume; Lundby, Carsten

    2014-05-15

    With this study we tested the hypothesis that 6 wk of endurance training increases maximal cardiac output (Qmax) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (Vo2max 47 ± 5 ml·min(-1)·kg(-1)) underwent supervised training (60 min; 4 times weekly at 65% Vo2max for 6 wk), and Qmax was determined by inert gas rebreathing during cycle ergometer exercise before and after the training period. After the training period, blood volume (determined in duplicates by CO rebreathing) was reestablished to pretraining values by phlebotomy and Qmax was quantified again. Resting echography revealed no structural heart adaptations as a consequence of the training intervention. After the training period, plasma volume (PV), red blood cell volume (RBCV), and BV increased (P < 0.05) by 147 ± 168 (5 ± 5%), 235 ± 64 (10 ± 3%), and 382 ± 204 ml (7 ± 4%), respectively. Vo2max was augmented (P < 0.05) by 10 ± 7% after the training period and decreased (P < 0.05) by 8 ± 7% with phlebotomy. Concomitantly, Qmax was increased (P < 0.05) from 18.9 ± 2.1 to 20.4 ± 2.3 l/min (9 ± 6%) as a consequence of the training intervention, and after normalization of BV by phlebotomy Qmax returned to pretraining values (18.1 ± 2.5 l/min; 12 ± 5% reversal). Thus the exercise training-induced increase in BV is the main mechanism increasing Qmax after 6 wk of endurance training in previously untrained subjects.

  12. Does the incremental shuttle walk test require maximal effort in young obese women?

    PubMed Central

    Jürgensen, S.P.; Trimer, R.; Di Thommazo-Luporini, L.; Dourado, V.Z.; Bonjorno-Junior, J.C.; Oliveira, C.R.; Arena, R.; Borghi-Silva, A.

    2016-01-01

    Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 – age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option. PMID:27409333

  13. The acute effects of flotation restricted environmental stimulation technique on recovery from maximal eccentric exercise.

    PubMed

    Morgan, Paul M; Salacinski, Amanda J; Stults-Kolehmainen, Matthew A

    2013-12-01

    Flotation restricted environmental stimulation technique (REST) involves compromising senses of sound, sight, and touch by creating a quiet dark environment. The individual lies supine in a tank of Epsom salt and water heated to roughly skin temperature (34-35° C). This study was performed to determine if a 1-hour flotation REST session would aid in the recovery process after maximal eccentric knee extensions and flexions. Twenty-four untrained male students (23.29 ± 2.1 years, 184.17 ± 6.85 cm, 85.16 ± 11.54 kg) participated in a randomized, repeated measures crossover study. The participants completed 2 exercise and recovery protocols: a 1-hour flotation REST session and a 1-hour seated control (passive recovery). After isometric muscle strength testing, participants were fatigued with eccentric isokinetic muscle contractions (50 repetitions at 60°·s) of the nondominant knee extensors and flexors. Blood lactate, blood glucose, heart rate, OMNI-rating of perceived exertion for resistance exercise (OMNI-RPE), perceived pain, muscle soreness, and isometric strength were collected before exercise, after treatment, and 24 and 48 hours later. A multivariate analysis of covariance found that treatment had a significant main effect on blood lactate, whereas subsequent univariate analyses of variance found statistical significance with the immediate posttreatment blood lactate measures. The results indicate that flotation REST appears to have a significant impact on blood lactate and perceived pain compared with a 1-hour passive recovery session in untrained healthy men. No difference was found between conditions for muscle strength, blood glucose, muscle soreness, heart rate, or OMNI-RPE. Flotation REST may be used for recreational and professional athletes to help reduce blood lactate levels after eccentric exercise.

  14. The efficacy of ergometry determined heart rates for flatwater kayak training.

    PubMed

    van Someren, K A; Oliver, J E

    2002-01-01

    The aim of this study was to investigate the use of incremental ergometry determined heart rate training intensities for the control of kayak ergometer and open water kayak training. Eight well-trained male kayakers completed a maximal incremental exercise test on an air-braked kayak ergometer for the determination of LT(1) (the power output at which blood lactate concentration increased by > or = 1 mmol x L(-1)), the associated heart rate (HR-LT(1)), VO(2)peak, maximal heart rate and maximal aerobic power. Subjects then performed 20 min trials of kayak ergometry (E), open water kayaking in a single kayak (K1) and open water kayaking in a four-seat kayak (K4) at HR-LT(1). During the three trials, heart rate was continuously measured, and blood lactate concentration, rating of perceived exertion (RPE) and stroke rate were determined every 5 min. In all trials, exercise at HR-LT(1) resulted in stable blood lactate concentrations and a stable RPE. Comparison of the three trials demonstrated that the only difference was for RPE, which was lower in (K4) than in (E), (p < 0.05). The results demonstrate that the prescription of HR-LT(1) elicits similar blood lactate concentrations during kayak ergometer and open water kayak training in both single and team boats.

  15. Effect of muscle mass and intensity of isometric contraction on heart rate.

    PubMed

    Gálvez, J M; Alonso, J P; Sangrador, L A; Navarro, G

    2000-02-01

    The purpose of this study was to determine the effect of muscle mass and the level of force on the contraction-induced rise in heart rate. We conducted an experimental study in a sample of 28 healthy men between 20 and 30 yr of age (power: 95%, alpha: 5%). Smokers, obese subjects, and those who performed regular physical activity over a certain amount of energetic expenditure were excluded from the study. The participants exerted two types of isometric contractions: handgrip and turning a 40-cm-diameter wheel. Both were sustained to exhaustion at 20 and 50% of maximal force. Twenty-five subjects finished the experiment. Heart rate increased a mean of 15.1 beats/min [95% confidence interval (CI): 5.5-24.6] from 20 to 50% handgrip contractions, and 20.7 beats/min (95% CI: 11.9-29.5) from 20 to 50% wheel-turn contractions. Heart rate also increased a mean of 13.3 beats/min (95% CI: 10.4-16.1) from handgrip to wheel-turn contractions at 20% maximal force, and 18.9 beats/min (95% CI: 9. 8-28.0) from handgrip to wheel-turn contractions at 50% maximal force. We conclude that the magnitude of the heart rate increase during isometric exercise is related to the intensity of the contraction and the mass of the contracted muscle.

  16. Treadmill performance and cardiac function in selected patients with coronary heart disease

    SciTech Connect

    McKirnan, M.D.; Sullivan, M.; Jensen, D.; Froelicher, V.F.

    1984-02-01

    To investigate the cardiac determinants of treadmill performance in patients able to exercise to volitional fatigue, 88 patients with coronary heart disease free of angina pectoris were tested. The exercise tests included supine bicycle radionuclide ventriculography, thallium scintigraphy and treadmill testing with expired gas analysis. The number of abnormal Q wave locations, ejection fraction, end-diastolic volume, cardiac output, exercise-induced ST segment depression and thallium scar and ischemia scores were the cardiac variables considered. Rest and exercise ejection fractions were highly correlated to thallium scar score (r . -0.72 to -0.75, p less than 0.001), but not to maximal oxygen consumption (r . 0.19 to 0.25, p less than 0.05). Fifty-five percent of the variability in predicting treadmill time or estimated maximal oxygen consumption was explained by treadmill test-induced change in heart rate (39%), thallium ischemia score (12%) and cardiac output at rest (4%). The change in heart rate induced by the treadmill test explained only 27% of the variability in measured maximal oxygen consumption. Myocardial damage predicted ejection fraction at rest and the ability to increase heart rate with treadmill exercise appeared as an essential component of exercise capacity. Exercise capacity was only minimally affected by asymptomatic ischemia and was relatively independent of ventricular function.

  17. [Ischaemic heart disease].

    PubMed

    Brotons, Carlos; Cuende, José I; Fernández Pardo, Jacinto; Plana, Nuria; Moral, Irene

    2013-01-01

    In the year 2011, cardiovascular diseases were responsible of 31.2% of total deaths in Spain. The absolute number of cases of acute coronary syndrome in this year will be approximately 115,752 cases (95%CI: 114,822-116,687). The prevalence of stable angina in the population aged 25-74 years is 2.6% in men and 3.5% in women. Cardiovascular diseases were in the year 2011 the first cause of hospitalizations representing 14.1% of the total hospitalizations. Diagnose of ischaemic heart disease and acute myocardial infarction were responsible of 110,950 and 50,064 hospitalizations, respectively. In the year 2003, the hospitalization rate was 314 while in the year 2011 was 237 per 100,000, a reduction of 24.4%. The average cost of hospitalization due to ischaemic heart disease in 1997 was 3,093.7euros while in the year 2011 was 7,028.71euros. Cardiovascular mortality rates have decreased from 2007 to 2011, showing a relative reduction of 7% in women and 8% in men. With regard to myocardial infarction, it was observed a relative reduction of 17% in men and 20% in women. According to EUROASPIREIII survey done in 8,966 patients with ischaemic heart disease in Europe, 17% of patients were still smokers, 35% were obese, 56% has uncontrolled blood pressure, 51% has raised blood cholesterol and 25% were diabetics. With regard to drugs utilisation, 91% were treated with antiplatelets agents, 80% with beta blockers, 71% with ACE inhibitors/ARBs.

  18. The total artificial heart.

    PubMed

    Meyer, A; Slaughter, M

    2011-09-01

    In the 1960s, cardiac surgeons and biomedical engineers pioneered the development of total artificial hearts (TAH) for the treatment of left and right heart failure. As we mark the 10th anniversary of the first implantation of the AbioCor device, the use of TAH has been limited, having failed to reach its envisioned potential and promise as an alternative therapy to heart transplantation. The Syncardia/CardioWest device, originally developed 30 years ago as the Jarvik TAH and later renamed the CardioWest TAH, continues to be used clinically in over 50 centers within the US and Europe having supported over 900 patients worldwide. Syncardia continues to develop TAH technology as evidenced by their recent introduction of a new portable pneumatic driver that enables patients to be discharged from the hospital. In contrast to TAH devices, continuous flow ventricular assist devices (VAD) have made tremendous technological strides and are rapidly gaining widespread clinical acceptance. The VAD technology has demonstrated extraordinary safety and reliability records through evolving technologies, advanced biocompatible materials, and improved patient management. Subsequently, the number of TAH implantations remains low compared to the growth in LVAD implants. Nonetheless, the Syncardia/CardioWest TAH remains an important and viable option for patients with severe biventricular failure and end organ dysfunction. Overall, a 79% survival rate has been achieved in patients supported with a Syncardia/CardioWest TAH as bridge-to-transplantation. In this review article, a brief history on the evolution of TAH devices, their current use and emerging use of evolving continuous flow VAD technology as chronic biventricular and TAH device systems are presented.

  19. Long maximal incremental tests accurately assess aerobic fitness in class II and III obese men.

    PubMed

    Lanzi, Stefano; Codecasa, Franco; Cornacchia, Mauro; Maestrini, Sabrina; Capodaglio, Paolo; Brunani, Amelia; Fanari, Paolo; Salvadori, Alberto; Malatesta, Davide

    2015-01-01

    This study aimed to compare two different maximal incremental tests with different time durations [a maximal incremental ramp test with a short time duration (8-12 min) (STest) and a maximal incremental test with a longer time duration (20-25 min) (LTest)] to investigate whether an LTest accurately assesses aerobic fitness in class II and III obese men. Twenty obese men (BMI≥35 kg.m-2) without secondary pathologies (mean±SE; 36.7±1.9 yr; 41.8±0.7 kg*m-2) completed an STest (warm-up: 40 W; increment: 20 W*min-1) and an LTest [warm-up: 20% of the peak power output (PPO) reached during the STest; increment: 10% PPO every 5 min until 70% PPO was reached or until the respiratory exchange ratio reached 1.0, followed by 15 W.min-1 until exhaustion] on a cycle-ergometer to assess the peak oxygen uptake [Formula: see text] and peak heart rate (HRpeak) of each test. There were no significant differences in [Formula: see text] (STest: 3.1±0.1 L*min-1; LTest: 3.0±0.1 L*min-1) and HRpeak (STest: 174±4 bpm; LTest: 173±4 bpm) between the two tests. Bland-Altman plot analyses showed good agreement and Pearson product-moment and intra-class correlation coefficients showed a strong correlation between [Formula: see text] (r=0.81 for both; p≤0.001) and HRpeak (r=0.95 for both; p≤0.001) during both tests. [Formula: see text] and HRpeak assessments were not compromised by test duration in class II and III obese men. Therefore, we suggest that the LTest is a feasible test that accurately assesses aerobic fitness and may allow for the exercise intensity prescription and individualization that will lead to improved therapeutic approaches in treating obesity and severe obesity.

  20. Determinants of maximal oxygen uptake in moderate acute hypoxia in endurance athletes.

    PubMed

    Mollard, Pascal; Woorons, Xavier; Letournel, Muriel; Lamberto, Christine; Favret, Fabrice; Pichon, Aurélien; Beaudry, Michèle; Richalet, Jean-Paul

    2007-08-01

    The factors determining maximal oxygen consumption were explored in eight endurance trained subjects (TS) and eight untrained subjects (US) exposed to moderate acute normobaric hypoxia. Subjects performed maximal incremental tests at sea level and simulated altitudes (1,000, 2,500, 4,500 m). Heart rate (HR), stroke volume (SV), cardiac output (.Q), arterialized oxygen saturation (Sa'O2), oxygen uptake (.VO2max), ventilation (.VE, expressed in normobaric conditions) were measured. At maximal exercise, ventilatory equivalent (.VE/.VO2max), O2 transport (.QaO2max) and O2 extraction (O2ERmax) were calculated. In TS, .Qmax remained unchanged despite a significant reduction in HRmax at 4,500 m. SVmax remained unchanged. .VEmax decreased in TS at 4,500 m, .VE/.VO2max was lower in TS and greater at 4,500 m vs. sea level in both groups. Sa'O2max decreased at and above 1,000 m in TS and 2,500 m in US, O2ERmax increased at 4,500 m in both groups. .QaO2max decreased with altitude and was greater in TS than US up to 2,500 m but not at 4,500 m. .VO2max decreased with altitude but the decrement (Delta.VO2max) was larger in TS at 4,500 m. In both groups Delta.VO2max in moderate hypoxia was correlated with Delta.QaO2max. Several differences between the two groups are probably responsible for the greater Delta.VO2max in TS at 4,500 m : (1) the relative hypoventilation in TS as shown by the decrement in .VEmax at 4,500 m (2) the greater.QaO2max decrement in TS due to a lower Sa'O2max and unchanged .Qmax 3) the smaller increase in O2ERmax in TS, insufficient to compensate the decrease in .QaO2max.