Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

The Influence Of Different Distances On Determination Of Critical Velocity In Swimmers [a Influência De Diferentes Distâncias Na Determinação Da Velocidade Crítica Em Nadadores]

The purpose of this study was to determine the influence of different distance combinations on critical velocity (CV) and anaerobic work capacity (AWC). Nineteen swimmers experienced in this training modality participated in the study. CV was calculated by the angular coefficient of the linear regression line between distance and time obtained for each repetition. Five distances (50, 100, 200, 400 and 800 m) performed at an interval of 24 hours were used for the determination of CV, followed by the following four combinations of distances: CV1 (50, 100 and 200 m), CV2 (100, 200 and 400 m), CV3 (200, 400 and 800 m), and CV4 (50, 100, 200, 400 and 800 m). The Shapiro-Wilk test was used to determine the normality of the data. One-way ANOVA was used for comparisons between CV and the different combinations of shots (p<0.05). The combination of smaller distances (CV1) resulted in an increase of CV (1.47 ± 0.13) and a decrease of AWC (11.91 ± 2.61). The use of shots of medium and long distance resulted in a lower CV (1.38 ± 0.10, 1.34 ± 0.09 and 1.36 ± 0.09 for CV2, CV3 and CV4, respectively) and higher AWC (19.84 ± 6.74, 27.44 ± 6.91 and 18.43 ± 5.21) when compared to short shots. The results suggest that shot distance influences CV and AWC, overestimating or underestimating the speed corresponding to maximum lactate steady state.112190194Monod, H., Scherrer, J., The work capacity of a synergic muscular group (1965) Ergonomics, 8 (3), pp. 329-338Hill, D.W., The critical power concept (1993) Sports Medicine, 16 (4), pp. 237-254Moritani, T., Nagata, A., deVries, H., Muro, M., Critical power as a measure of physical work capacity and anaerobic threshold (1981) Ergonomics, 24 (5), pp. 339-350Wakayoshi, K., Ilkuta, K., Yoshida, T., Determination and validity of critical velocity speed as an index of swimming performance in the competitive swimmer (1992) Eur J Appl Physiol Occup Physiol, 64 (2), pp. 153-157Wakayoshi, K., Yoshida, T., Udo, M., Kasai, T., Moritani, T., Mutoh, Y., A simple method for determining critical speed as swimming fatigue threshold in competitive swimming (1992) Int J Sports Med, 13 (5), pp. 367-371Wakayoshi, K., Yoshida, T., Udo, M., Harada, T., Moritani, T., Mutoh, Y., Does critical swimming velocity represent exercise intensity at maximal lactate steady state? (1993) Eur J Appl Physiol Occup Physiol, 66 (1), pp. 90-95Le Chevalier, J.M., Vandewalle, H., Thépaut-Mathieu, C., Stein, J.F., Caplan, L., Local critical power is an index of local endurance (2000) Eur J Appl Physiol, 81 (1-2), pp. 120-127Smith, C.G., Jones, A.M., The relationship between critical velocity, maximal lactate steady-state velocity and lactate turn point velocity in runners (2001) Eur J Appl Physiol, 85 (1-2), pp. 19-26Brickley, G., Doust, J., Williams, C.A., Physiological responses during exercise to exhaustion at critical power (2002) Eur J Appl Physiol, 88 (1-2), pp. 146-151Bull, A.J., Housh, T.J., Johnson, G.O., Perry, S.R., Effect of mathematical modeling on the estimation of critical power (2000) Med Sci Sports Exerc, 32, pp. 526-530Dekerle, J., Baron, B., Dupont, L., Vanvelcenher, J., Pelayo, P., Maximal lactate steady state, respiratory compensation threshold and critical power (2003) Eur J Appl Physiol, 89 (3-4), pp. 281-288Hughson, R.L., Orok, C.J., Stendt, L.E., A high velocity treadmill running test to assess endurance running potential (1984) Int J Sports Med, 5 (1), pp. 23-25Martin, L., Whyte, G.P., Comparison of critical swimming velocity and velocity at lactate threshold in elite triathletes (2000) Int J Sports Med, 21 (5), pp. 366-368Denadai, B.S., Greco, C.C., Teixeira, M., Blood lactate response and critical speed in swimmers aged 10-12 years of different standards (2000) J Sports Sci, 18 (10), pp. 779-784Bishop, D., Jenkins, D.G., Howard, A., The critical power function is dependent on the duration of the predictive exercise tests chosen (1998) Int J Sports Med, 19 (1), pp. 125-129Jenkins, D.G., Quigley, B.M., Blood lactate in trained cyclists during cycle ergometry at critical power (1990) Eur J Appl Physiol Occup Physiol, 61 (4), pp. 278-283Housh, D.J., Housh, T.J., Bauge, S.M., A methodological consideration for the determination of critical power and anaerobic work capacity (1990) Res Q Exerc Sport, 61 (4), pp. 406-409Papoti, M., Zagatto, A.M., Mendes, O.C., Gobatto, C.A., Utilização de métodos invasivos e não invasivos na predição das performances aeróbia e anaeróbia em nadadores de nível nacional (2005) Rev Port Cien Desp, 5 (1), pp. 7-14Gaesser, G.A., Poole, D., The slow component of oxygen uptake kinetics in humans (1996) Exer Sport Sci Rev, 24, pp. 35-70Denadai, B.S., Greco, C., Critical speed endurance capacity in Young swimmers: Effects of gender and age (2005) Pediatric Exerc Sci, 17 (4), pp. 353-363Calis, J.F., Denadai, B.S., Influência das cargas selecionadas na determinação da potência crítica determinada no ergômetro de braço em dois modelos lineares (2000) Rev Bras Med Esporte, 6 (1), pp. 1-4Toubekis, A.G., Tsami, A.P., Tokmakidis, S.P., Critical Velocity and lactate threshold in Young swimmers (2006) Int J Sports Med, 27 (2), pp. 117-123Kokubun, E., Velocidade crítica como estimador do limiar anaeróbio na natação (1996) Rev Paul Educ Fis, 10 (1), pp. 5-20Tossaint, H.M., Wakayoshi, K., Hollander, A.P., Ogita, F., Simulated front crawl swimming performance related to critical speed and critical power (1998) Med Sci Sports Exerc, 30 (1), pp. 144-151Jenkins, D., Quigley, B.M., Endurance training enhances critical power (1992) Med Sci Sports Exerc, 24 (11), pp. 1283-1289Jenkins, D.G., Quigley, B.M., The influence of intensity exercise training on the Wlin-Tlin relationship (1993) Med Sci Sports Exerc., 25 (2), pp. 275-282Smith, J.C., Hill, D.W., Stability of parameters estimates from power/time relationship (1993) Can J Appl Physiol., 18 (1), pp. 43-47Miura, A., Sato, H., Whipp, B.J., Fukuba, Y., The effect of glycogen depletion on the curvature constant parameter of the power-duration curve for cycle ergometry (2000) Ergonomics, 46 (1), pp. 133-141McHado, M.V., Batista, A.R., Marques, A.C., Baleixo, R., Andries Jr., O., Influência do intervalo sobre a determinação da velocidade crítica em nadadores (2007) Rev Educ Fís, 18 (SUPPL.), pp. 112-115Smith, J.C., Stephens, D.P., Hall, E.L., Jackson, A.W., Earnest, C.P., Effect of oral creatine ingestion on parameters of work-time relationship and time to exhaustion in high-intensity cycling (1998) Eur J Appl Physiol, 77 (4), pp. 360-365Eckerson, J.M., Stout, J.R., Moore, G.A., Stone, N.J., Nishimura, K., Tamura, K., Effect of two and five days of creatine loading on anaerobic working capacity in women (2004) J Strength Cond Res, 18 (1), pp. 168-173Nakamura, F.Y., Gancedo, M.R., Silva, L.A., Lima, J.R., Kokubun, E., Utilização do esforço percebido na determinação da velocidade crítica em corrida aquática (2005) Rev Bras Med Esporte, 11 (1), pp. 1-

Effect Of Caffeine Intake On Critical Power Model Parameters Determined On A Cycle Ergometer [efeito Da Ingestão De Cafeína Sobre Os Parâmetros Da Potência Crítica]

The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg) or placebo (maltodextrin) 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively). The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p&lt;0.01). A high association (r2) was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively). We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.1214954Davis, J.M., Zhao, Z., Stock, H.S., Mehl, K.A., Buggy, J., Hand, G.A., Central nervous system effects of caffeine and adenosine on fatigue (2003) Am J Physiol, 284 (SUPPL.), pp. R399-R404Graham, T.E., Caffeine and exercise: Metabolism, endur-endurance and performance (2001) Sports Med, 31 (11), pp. 785-807Lindinger, M.I., Graham, T.E., Spriet, L.L., Caffeine attenuates the exercise-induced increases in plasma [K+] in humans (1993) J Appl Physiol, 74 (3), pp. 1149-1155Tarnopolsky, M.A., Cupido, C., Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine users (2000) J Appl Physiol, 89 (5), pp. 1719-1724Graham, T.E., Rush, J.W., van Soeren, M.H., Caffeine and exercise: Metabolism and performance (1994) Can J Appl Physiol, 19 (2), pp. 111-138Greer, F., Friars, D., Graham, T.E., Comparison of caffeine and theophylline ingestion: Exercise metabolism and endurance (2000) J Appl Physiol, 89 (5), pp. 1837-1844Bruce, C.R., Anderson, M.E., Fraser, S.F., Stepto, N.K., Klein, R., Hopkins, W.G., Enhancement of 2000-m rowing performance after caffeine ingestion (2000) Med Sci Sports Exerc, 32 (11), pp. 1958-1963Doherty, M., Smith, P.M., Hughes, M.G., Davison, R.C., Caffeine lowers percentual response and increases power output during high-intensity cycling (2004) J Sports Sci, 22 (7), pp. 637-643Jackman, M., Wendling, P., Friars, D., Graham, T.E., Metabolic, catecholamine and endurance responses to caffeine during intense exercise (1996) J Appl Physiol, 81 (4), pp. 1658-1663Spriet, L.L., Caffeine and performance (1995) Int J Sports Nutr, 5 (SUPPL.), pp. S84-S99Kalmar, J.M., Caffarelli, E., Caffeine: A valuable tool to study central fatigue in humans (2004) Exerc Sport Sci Rev, 32 (4), pp. 143-147Monod, H., Sherrer, J., The work capacity of a synergic muscular group (1965) Ergonomics, 8 (3), pp. 329-338Wakayoshi, K., Ilkuta, K., Yoshida, T., Determination and validity of critical velocity speed as an index of swimming performance in the competitive swimmer (1992) Eur J Appl Physiol Occup Physiol, 64 (2), pp. 153-157Wakayoshi, K., Yoshida, T., Udo, M., Harada, T., Moritani, T., Mutoh, Y., Does critical swimming velocity represent exercise intensity at maximal lactate steady state (1993) Eur J Appl Physiol Occup Physiol, 66 (1), pp. 90-95Moritani, T., Nagata, A., Devries, H., Muro, M., Critical power as a measure of physical work capacity and anaerobic threshold (1981) Ergonomics, 24 (5), pp. 339-350le Chevalier, J.M., Vandewalle, H., Thépaut-Mathieu, C., Stein, J.F., Caplan, L., Local critical power is an index of local endurance (2000) Eur J Appl Physiol, 81 (1-2), pp. 120-127Hill, D.W., Smith, J.C., A method to ensure the accuracy of estimates of anaerobic capacity derived using the critical power concept (1994) J Sports Med Phys Fitness, 34 (1), pp. 23-37Calis, J.F., Denadai, B.S., Influência das cargas selecionadas na determinação da potência crítica determinada no ergômetro de braço em dois modelos lineares (2000) Rev Bras Med Esporte, 6 (1), pp. 1-4Housh, D.J., Housh, T.J., Bauge, S.M., A methodological consideration for the determination of critical power and anaerobic work capacity (1990) Res Quarterly Exerc Sport, 61 (4), pp. 406-409Miura, A., Sato, H., Whipp, B.J., Fukuba, Y., The effect of glycogen depletion on the curvature constant parameter of the power-duration curve for cycle ergometry (2000) Ergonomics, 46 (1), pp. 133-141Smith, J.C., Stephens, D.P., Hall, E.L., Jackson, A.W., Earnest, C.P., Effect of oral creatine ingestion on parameters of work-time relationship and time to exhaustion in high-intensity cycling (1998) Eur J Appl Physiol, 77 (4), pp. 360-365Eckerson, J.M., Stout, J.R., Moore, G.A., Stone, N.J., Nishimura, K., Tamura, K., Effect of two and five days of creatine loading on anaerobic working capacity in women (2004) J Strength Condit Res, 18 (1), pp. 168-173Jenkins, D.G., Quigley, B.M., Endurance training enhances critical power (1992) Med Sci Sports Exerc, 24 (11), pp. 1283-1289Jenkins, D.G., Quigley, B.M., The influence of high-intensity exercise training on the Wlin-Tlim relationship (1993) Med Sci Sports Exerc, 25 (2), pp. 275-282Anselme, F., Collomp, K., Mercier, B., Ahmaidi, S., Prefaut, C., Caffeine increases maximal anaerobic power and blood lactate concentration (1992) Eur J Appl Physiol, 65 (2), pp. 188-191Paton, C.D., Hopkins, W.G., Volebregt, L., Little effect of caffeine ingestion on repeated sprints in team-sport athletes (2001) Med Sci Sports Exerc, 33 (5), pp. 822-825Jackman, M., Wendling, A., Friars, D., Graham, T.E., Metabolic, catecholamine, and endurance responses to caffeine during intense exercise (1996) J Appl Physiol, 81 (4), pp. 1658-1663Doherty, M., The effects of caffeine on the maximal accumulated oxygen deficit and short-term running performance (1998) Int J Sports Nutr, 8 (2), pp. 95-104Bell, D.G., Jacobs, I., Ellerington, K., Effect of caffeine and ephedrine ingestion on anaerobic exercise performance (2001) Med Sci Sports Exerc, 33 (11), pp. 1399-1403Alves, M.N., Ferrari-Auarek, W.M., Pinto, K.M.C., Sá, K.R., Viveiros, J.P., Pereira, H.A.A., Effects of caffeine on tryptophan on rectal temperature, metabolism, total exercise time, rate of perceived exertion and heart rate (1995) Braz J Med Biol Res, 28 (6), pp. 705-709Butts, N.K., Crowell, D., Effect of caffeine ingestion on cardiorespiratory endurance in men and women (1985) Res Q Exerc Sport, 56 (4), pp. 301-30

Electromyographic Response Of The Abdominal Muscles During Curl-up Exercises With Different Loads

Aim. The present study focuses on the behavior of the abdominal muscles when performing curl-ups with loads gauged in relation to a maximum load test (1 RM). Methods. Thirteen subjects performed curl-up exercises with loads equivalent to 80, 60, 40 and 20% of the 1 RM (100%) maximum, with 5-minute rests between sets. Surface bipolar EMG electrodes were placed on the right and left Rectus Abdominis and the Obliquus Externus muscle. Differences between loads and repetitions were determined using the Shapiro-Wilk, ANOVA (Friedman) and Wilcoxon tests (P<0.05). Results. The root mean square (RMS) of the EMG was calculated for the first four and the last three repetitions. The percentage values for the abdominal muscles studied were then averaged and the result was used to represent abdominal synergy (AbSyn). Conclusion. Considering AbSyn to be a representative measure of the abdominal muscles in general, we concluded that the abdominal muscles were more strongly recruited in the 100% category than under any other external load conditions. Overall, the most significant differences were between the 20% load and the other loads. Furthermore, as recognized in the literature, to maximize safety during the performance of abdominal exercises and minimize the compression of the lumbar spine, the use of heavy loads during the movement is not indicated. When using loads, therefore, we suggest giving priority to those in the 20% and 40% ranges.1685289296Edgerton, V.R., Roy, R.R., Regulation of skeletal muscle fiber size, shape and function (1991) J Biomech, 24, pp. 123-133Enoka, R.M., (2000) Bases neuromecânicas da cinesiologia, , 2nd ed. São Paulo: Editora Manole;Delp, S.L., Suryanarayanan, S., Murray, W.M., Uhlir, J., Triolo, R.J., Architecture of the rectus abdominis, quadratus lumborum and erector spinae (2001) J Biomech, 34, pp. 371-375Gans, C., Fiber architecture and muscle function (1982) Exerc Sport Sci Rev, 10, pp. 160-207Haggmark, T., Thorstensson, A., Fibre types in human abdominal muscles (1979) Acta Physiol Scand, 107, pp. 319-325Johnson, M.A., Polgar, J., Weightman, D., Appleton, D., Data on the distribution of fibre types in thirty-six human muscles: An autopsy study (1973) J Neurol Sci, 18, pp. 111-129Rasch, P.J., Burke, R.K., (1977) Cinesiologia e anatomia aplicada: A ciência do movimento humano, , 5th ed. Rio de Janeiro: Guanabara Koogan;Sakkas, G.K., Ball, D., Mercer, T.H., Naish, P.F., An alternative histochemical method to simultaneously demonstrate muscle nuclei and muscle fibre type (2003) Eur J Appl Physiol, 89, pp. 503-505Marquez, A., Finol, H.J., Ultrastructural fiber typing of human abdominal muscles obliquus internus and obliquus externus (1990) Acta Cient Venez, 41, pp. 40-42Flint, M.M., Abdominal muscle involvement during the performance of various forms of sit-up exercise. An electromyographic study (1965) Am J Phys Med, 44, pp. 224-234Flint, M.M., Gudgell, J., Electromyographic study of abdominal muscular activity during exercise (1965) Res Q, 36, pp. 29-37Bankoff, A.D.P., Furlani, J., Estudo eletromiográfico dos músculos: Reto abdominal e oblíquo externo. (1986) Rev Bras Ciênc Morfol, 2, pp. 48-54Guimaraes, A.C., Vaz, M.A., De Campos, M.I., Marantes, R., The contribution of the rectus abdominis and rectus femoris in twelve selected abdominal exercises: An electromyographic study (1991) J Sports Med Phys Fitness, 31, pp. 222-230Moraes, A.C., Bankoff, A.D., Pellegrinotti, L.L., Moreira, Z.W., Galdi, E.H., Electromyography analysis of the rectus abdominis and external oblique muscles of children 8 to 10 years old (1995) Electromyogr Clin Neurophysiol, 35, pp. 425-430Moraes, A.C., Bankoff, A.D., Almeida, T.L., Simoes, E.C., Rodrigues, C.E., Okano, A.H., Using weights in abdominal exercises: Electromyography response of the rectus abdominis and rectus femoris muscles (2003) Electromyogr Clin Neurophysiol, 43, pp. 487-496Pezarat-Correia, P., Nobre, H., Cabri, J., Canto de Loura, L., Melo, F., Comparison of abdominal muscles activation during different curl-up exercises in women (2002) Proceedings Book of the 3rd International Scientific Conference of Kinesiology, pp. 721-724. , Zagreb: University of Zagreb;Pezarat-Correia, P., Nobre, H., Cabri, J., Comparation of abdominal wall activation during sit-up and curl-up exercises in women (2002) Proceedings of the XX International Symposium on Biomechanics in Sports, pp. 425-428. , Gianikelis K editor, Cáceres: Universidad de Extremadura;Pezarat-Correia, P., Nobre, H., Cabri, C., Canto de Loura, L., Differences in EMG activation of upper and lower portions of the rectus abdominis during different exercises (2003) Med Sci Sports Exerc, 35 (5 SUPPL.), pp. S1063Whiting, W.C., Rugg, S., Coleman, A., Vincent, W.J., Muscle activity during sit-ups using abdominal exercise devices (1999) J Strength Cond Res, 13, pp. 339-345Escamilla, R.F., Babb, E., Dewitt, R., Jew, P., Kelleher, P., Burnham, T., Electromyographic analysis of traditional and nontraditional abdominal exercises: Implications for rehabilitation and training (2006) Phys Ther, 86, pp. 656-671Olson, M.S., Esco, M.R., Williford, H., The EMG of conventional abdominal exercise and exercise with a semi-upright commercial device: Comparative effects and technique considerations (2008) J Sports Med Phys Fitness, 48, pp. 43-48Sternlicht, E., Rugg, S., Fujii, L.L., Tomomitsu, K.F., Seki, M.M., Electromyographic comparison of a stability ball crunch with a traditional crunch (2007) J Strength Cond Res, 21, pp. 506-509Bressel E, Willardson JM, Thompson B, Fontana FE. 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Vorapaxar in the secondary prevention of atherothrombotic events

Item does not contain fulltextBACKGROUND: Thrombin potently activates platelets through the protease-activated receptor PAR-1. Vorapaxar is a novel antiplatelet agent that selectively inhibits the cellular actions of thrombin through antagonism of PAR-1. METHODS: We randomly assigned 26,449 patients who had a history of myocardial infarction, ischemic stroke, or peripheral arterial disease to receive vorapaxar (2.5 mg daily) or matching placebo and followed them for a median of 30 months. The primary efficacy end point was the composite of death from cardiovascular causes, myocardial infarction, or stroke. After 2 years, the data and safety monitoring board recommended discontinuation of the study treatment in patients with a history of stroke owing to the risk of intracranial hemorrhage. RESULTS: At 3 years, the primary end point had occurred in 1028 patients (9.3%) in the vorapaxar group and in 1176 patients (10.5%) in the placebo group (hazard ratio for the vorapaxar group, 0.87; 95% confidence interval [CI], 0.80 to 0.94; P<0.001). Cardiovascular death, myocardial infarction, stroke, or recurrent ischemia leading to revascularization occurred in 1259 patients (11.2%) in the vorapaxar group and 1417 patients (12.4%) in the placebo group (hazard ratio, 0.88; 95% CI, 0.82 to 0.95; P=0.001). Moderate or severe bleeding occurred in 4.2% of patients who received vorapaxar and 2.5% of those who received placebo (hazard ratio, 1.66; 95% CI, 1.43 to 1.93; P<0.001). There was an increase in the rate of intracranial hemorrhage in the vorapaxar group (1.0%, vs. 0.5% in the placebo group; P<0.001). CONCLUSIONS: Inhibition of PAR-1 with vorapaxar reduced the risk of cardiovascular death or ischemic events in patients with stable atherosclerosis who were receiving standard therapy. However, it increased the risk of moderate or severe bleeding, including intracranial hemorrhage. (Funded by Merck; TRA 2P-TIMI 50 ClinicalTrials.gov number, NCT00526474.)