899 resultados para Interval arithmetic
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We reconstructed Middle Pleistocene surface hydrography in the western South Atlantic based on planktonic foraminiferal assemblages, modern analog technique and Globorotalia truncatulinoides isotopic ratios of core SP1251 (38 degrees 29.7`S / 53 degrees 40.7`W / 3400 m water depth). Biostratigraphic analysis suggests that sediments were deposited between 0.3 and 0.12 Ma and therefore correlate to Marine Isotopic Stage 6 or 8. Faunal assemblage-based winter and summer SST estimates suggest that the western South Atlantic at 38 degrees S was 4-6 degrees C colder than at present, within the expected range for a glacial interval. High relative abundances of subantarctic species, particularly the dominance of Neogloboquadrina pachyderma (left), support lower than present SSTs throughout the recorded period. The oxygen isotopic composition of G. truncatulinoides suggests a northward shift of the Brazil-Malvinas Confluence Zone and of the associated mid-latitude frontal system during this Middle Pleistocene cold period, and a stronger than present influence of superficial subantarctic waters and lowering in SSTs at our core site during the recorded Middle Pleistocene glacial.
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AIM: We sought to evaluate the predictive validity of the Waterlow Scale in hospitalized patients. SUBJECTS AND SETTING: The study was conducted at a general private hospital with 220 beds and a mean time of hospitalization of 7.4 days and a mean occupation rate of approximately 80%. Adult patients with a Braden Scale score of 18 or less and a Waterlow Scale score of 16 or more were studied. The sample consisted of 98 patients with a mean age of 71.1 +/- 15.5 years. METHODS: Skin assessment and scoring by using the Waterlow and Braden scales were completed on alternate days. Patients were examined at least 3 times to be considered for analysis. The data were submitted to sensitivity and specificity analysis by using receiver operating characteristic (ROC) curves and positive (+LR) and negative (-LR) likelihood ratios. RESULTS: The cutoff scores were 17, 20, and 20 in the first, second, and third assessment, respectively. Sensitivity was 71.4%, 85.7%, and 85.7% and specificity was 67.0%, 40.7%, and 32.9%, respectively. Analysis of the area under the ROC curve revealed good accuracy (0.64, 95% confidence interval [CI]: 0.35-0.93) only for the cutoff score 17 in the first assessment. The results also showed probabilities of 14%, 10%, and 9% for the development of pressure ulcer when the test results were positive (+LR) and of 3% (-LR) when the test results were negative for the cutoff scores in the first, second, and third assessment, respectively. CONCLUSION: The Waterlow Scale achieved good predictive validity in predicting pressure ulcer in hospitalized patients when a cutoff score of 17 was used in the first assessment.
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Objective: to identify risk factors associated with neonatal transfers from a free-standing birth centre to a hospital. Design: epidemiological case-control study. Setting: midwifery-led free-standing birth centre in Sao Paulo, Brazil. Participants: 96 newborns were selected from 2840 births between September 1998 and August 2005. Cases were defined as all new borns transferred from the birth centre to a hospital (n = 32), and controls were defined as new borns delivered at the same birth centre, during the same time period, and who had not been transferred to a hospital (n = 64). Measurements and findings: data were collected from medical records available at the birth centre. Univariate and multivariate analyses were performed using logistic regression. The multivariate analysis included outcomes with p<0.25, specifically: smoking during pregnancy, prenatal care appointments, labour complications, weight in relation to gestational age, and one-minute Apgar score. Of the foregoing outcomes, those that remained in the full regression model as a risk factor associated with neonatal transfer were: smoking during pregnancy [p = 0.009, odds ratio (OR) = 4.1,95% confidence interval (CI) 1.03-16.33], labour complications (p<0.001, OR = 5.5, 95% CI 1.06-28.26) and one-minute Apgar score <= 7 (p<0.001, OR = 7.8,95% CI 1.62-37.03). Key conclusions and implications for practice: smoking during pregnancy, labour complications and one-minute Apgar score <= 7 were confirmed as risk factors for neonatal transfer from the birth centre to a hospital. The identified risk factors can help to improve institutional protocols and formulate hypotheses for other studies. (C) 2009 Elsevier Ltd. All rights reserved.
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Objective: to investigate the use of local anaesthetics, in the presence or absence of vasoconstrictors, for perineal repair during spontaneous delivery. Design: double-blind, randomised-controlled trial. Setting: a birth centre, in the city of Sao Paulo, Brazil. Participants: from June to December 2004, a total of 96 women were allocated into three groups (first-degree perineal lacerations, second-degree perineal lacerations or episiotomy), and treated with local anaesthesia (1% lidocaine or 1% lidocaine with epinephrine) (n = 16 per treatment per group). Interventions: an initial local infiltration of the anaesthetic solution was given so that episiotomy could be carried out (5 ml) and to suture spontaneous lacerations (1 ml), followed by repeated doses (1 ml) until pain was completely inhibited. Measurements and findings: the main outcome measurement was the volume of anaesthetic used during episiotomy and perineal suture. Our data suggest that the concomitant use of the vasoconstrictor resulted in a significantly lower average volume used in the treatment of first-degree (1 ml, 95% confidence interval (0) 0.4-1.6) and second-degree (3.7 ml, 95% CI 1.6-5.8) lacerations (p = 0.002 and 0.001, respectively). A 0.3 ml (95% CI 1.5-2.1) average decrease in anaesthetic volume was observed with episiotomy (p = 0.724). The maximum volume of anaesthetic used with and without vasoconstrictor was 1-2 ml in 95% and 3-4 ml in 50% of first-degree lacerations, respectively, and 1-6 ml in 88% and 7-15 ml in 81% of second-degree lacerations, respectively. For episiotomy, the maximum dose was 15 ml, regardless of anaesthetic solution used. Key conclusions: our data confirm the hypothesis that the use of anaesthetics in conjunction with vasoconstrictors is more effective than anaesthetics alone in the repair of perineal lacerations, but not for episiotomy. (C) 2007 Elsevier Ltd. All rights reserved.
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Aims To test the effects of early exercise training (ET) on left ventricular (LV) and autonomic functions, haemodynamics, tissues blood flows (BFs), maximal oxygen consumption (VO(2) max), and mortality after myocardial infarction (MI) in rats. Methods and results Male Wistar rats were divided into: control (C), sedentary-infarcted (SI), and trained-infarcted (TI). One week after MI, TI group underwent an ET protocol (90 days, 50-70% VO2 max). Left ventricular function was evaluated noninvasively and invasively. Baroreflex sensitivity, heart rate variability, and pulse interval were measured. Cardiac output (CO) and regional BFs were determined using coloured microspheres. Infarcted area was reduced in TI (19 +/- 6%) compared with SI (34 +/- 5%) after ET. Exercise training improved the LV and autonomic functions, the CO and regional BF changes induced by MI, as well as increased SERCA2 expression and mRNA vascular endothelial growth factor levels. These changes brought about by ET resulted in mortality rate reduction in the TI (13%) group compared with the SI (54%) group. Conclusion Early aerobic ET reduced cardiac and peripheral dysfunctions and preserved cardiovascular autonomic control after MI in trained rats. Consequently, these ET-induced changes resulted in improved functional capacity and survival after MI.
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The aims of this study were (a) to assess the ability of the rating of perceived exertion (RPE) to predict performance (i.e. number of vertical jumps performed to a fixed jump height) of an intermittent vertical jump exercise, and (b) to determine the ability of RPE to describe the physiological demand of such exercise. Eight healthy men performed intermittent vertical jumps with rest periods of 4, 5, and 6s until fatigue. Heart rate and RPE were recorded every five jumps throughout the sessions. The number of vertical jumps performed was also recorded. Random coefficient growth curve analysis identified relationships between the number of vertical jumps and both RPE and heart rate for which there were similar slopes. In addition, there were no differences between individual slopes and the mean slope for either RPE or heart rate. Moreover, RPE and number of jumps were highly correlated throughout all sessions (r=0.97-0.99; P0.001), as were RPE and heart rate (r=0.93-0.97; P0.001). The findings suggest that RPE can both predict the performance of intermittent vertical jump exercise and describe the physiological demands of such exercise.
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The hypothesis that salivary cortisol would increase and salivary immunoglobulin A (IgA) decrease after a kickboxing match was tested among 20 male athletes. Saliva samples collected before and after the match were analyzed. Salivary cortisol and salivary IgA concentrations (absolute concentration, salivary IgAabs) and the secretion rate of IgA (salivary IgArate) were measured by enzyme-linked immunosorbent assay. A Wilcoxon test for paired samples showed significant increases in salivary cortisol from pre- to postmatch. No significant changes were observed in salivary IgAabs or secretory IgArate and saliva flow rate. This study indicates that a kickboxing match might increase salivary concentration and thereafter it could be considered a significant source of exercise-related stress. On the other hand, the effect of a kickboxing match on mucosal immunity seems not to be relevant.
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The aim of this study was to test if the critical power model can be used to determine the critical rest interval (CRI) between vertical jumps. Ten males performed intermittent countermovement jumps on a force platform with different resting periods (4.1 +/- 0.3 s, 5.0 +/- 0.4 s, 5.9 +/- 0.6 s). Jump trials were interrupted when participants could no longer maintain 95% of their maximal jump height. After interruption, number of jumps, total exercise duration and total external work were computed. Time to exhaustion (s) and total external work (J) were used to solve the equation Work = a + b . time. The CRI (corresponding to the shortest resting interval that allowed jump height to be maintained for a long time without fatigue) was determined dividing the average external work needed to jump at a fixed height (J) by b parameter (J/s). in the final session, participants jumped at their calculated CRI. A high coefficient of determination (0.995 +/- 0.007) and the CRI (7.5 +/- 1.6 s) were obtained. In addition, the longer the resting period, the greater the number of jumps (44 13, 71 28, 105 30, 169 53 jumps; p<0.0001), time to exhaustion (179 +/- 50, 351 +/- 120, 610 +/- 141, 1,282 +/- 417 s; p<0.0001) and total external work (28.0 +/- 8.3, 45.0 +/- 16.6, 67.6 +/- 17.8, 111.9 +/- 34.6 kJ; p<0.0001). Therefore, the critical power model may be an alternative approach to determine the CRI during intermittent vertical jumps.
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Moreira, A, Arsati, F, Cury, PR, Franciscon, C, Oliveira, PR, and Araujo, VC. Salivary immunoglobulin a response to a match in top-level brazilian soccer players. J Strength Cond Res 23(7): 1968-1973, 2009-It has been suggested that several parameters of mucosal immunity, including salivary immunoglobulin A (s-IgA), are affected by heavy exercise either in field sports or in the laboratory environment. Few observations have been made during a true sporting environment, particularly in professional soccer. We tested the hypothesis that salivary IgA levels will be decreased after a 70-minute regulation in a top-level professional soccer friendly match. Saliva samples from 24 male professional soccer players collected before and after the match were analyzed. Salivary immunoglobulin A concentration was measured by enzyme-linked immunosorbent assay and expressed as the absolute concentration (s-IgAabs), s-IgA relative to total protein concentration (IgA-Pro), and the secretion rate of IgA (s-IgArate). Rate of perceived exertion (RPE) was used to monitor the exercise intensity. The paired t-test showed no significant changes in s-IgAabs and s-IgArate (p > 0.05) from PRE to POST match. However, a significant (p < 0.05) increase in total protein concentration (1.46 +/- 0.4 to 2.00 +/- 07) and a decrease in IgA-Pro were observed. The best and most significant correlation was obtained with the RPE and changes in IgA-Pro (rs = -0.43) and could indicate that this expression may be an interesting marker of intensity in a soccer match. However, further investigation regarding exercise intensity, protein concentration, and immune suppression, particularly in team sports, is warranted. From a practical application, the variability of the responses among the players leads us to suggest that there is a need to individually analyze the results with team sports. Some athletes showed a decrease in s-IgA expressions, suggesting the need for taking protective actions to minimize contact with cold viruses or even reducing the training load.
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Matsushigue, KA, Hartmann, K, and Franchini, E. Taekwondo: Physiological responses and match analysis. J Strength Cond Res 23(4): 1112-1117, 2009-The aim of the present study was to determine the time structure and physiological responses during Songahm Taekwondo (TKD) competition and to compare these variables between winner and non-winner athletes. Fourteen men subjects were analyzed. Blood lactate concentration (LA) and heart rate (HR) were determined before and after the match. The match was filmed for the determination of the number of techniques used, the duration of effort and rest periods (RPs), and the interval between high-intensity movements (HM). Post-match LA was 7.5 +/- 3.8 mmol.L(-1), HR was 183 +/- 9 b.min(-1), and HM was 31 +/- 16 seconds. The mean effort time (862 seconds) did not differ from mean interval time (8 +/- 3 seconds). Winners used a smaller total number of techniques, but post-match LA or HR did not differ from that of non-winners. In conclusion, the glycolytic metabolism was not the predominant energy source and the physiological responses did not differ between winners and non-winners. Coaches and sports scientists should prepare a technical or physical training session considering the low glycolytic contribution in this sport, hence the training protocol should involve high-intensity movements interspersed with longer RPs to provide the creatine phosphate recovery, with special attention given to the technical quality of TKD skills and not to higher technique volume during a simulation of matches.
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The aim of this study was to directly compare the causes of fatigue after a short- and a long-rest interval between consecutive stretch-shortening cycle exercises. Eleven healthy males jumped with different resting period lengths (short = 6.1 +/- 1 s, long = 8.6 +/- 0.9 s), performing countermovement jumps at 95% of their maximal jump height until they were unable to sustain the target height. After short- and long-rest, the maximal voluntary isometric contraction knee extension torque decreased (-7%; p = 0.04), comparing to values obtained before exercise protocols. No change was seen from pre- to post-exercise, for either short- or long-rest, in biceps femoris coactivation (-1%; p = 0.95), peak-to-peak amplitude (1%; p = 0.95) and duration (-8%; p = 0.92) of the compound muscle action potential of the vastus lateralis. Evoked peak twitch torque reduced after both exercise protocols (short = -26%, long = -32%; p = 0.003) indicating peripheral fatigue. However, central fatigue occurred only after short-rest evidenced by a reduction in voluntary activation of the quadriceps muscle (-14%; p = 0.013) measured using the interpolated twitch technique. In conclusion, after Stretch-shortening cycle exercise using short rest period length, the cause of fatigue was central and peripheral, while after using long rest period length, the cause of fatigue was peripheral.
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This investigation examined the impact of a 17-d training period (that included basketball-specific training, sprints, intermittent running exercises, and weight training, prior to an international championship competition) on salivary immunoglobulin A (SIgA) levels in 10 subjects (athletes and staff members) from a national basketball team, as a biomarker for mucosal immune defence. Unstimulated saliva samples were collected at rest at the beginning of the preparation for the Pan American Games and 1 d before the first game. The recovery interval from the last bout of exercise was 4 h. The SIgA level was measured using enzyme-linked immunosorbent assay and expressed as absolute concentrations, secretion rate, and SIgA level relative to total protein. The decrease in SIgA levels following training was greater in athletes than in support staff; however, no significant differences between the two groups were detected. A decrease in SIgA level, regardless of the method used to express IgA results, was verified for athletes. Only one episode of upper respiratory tract illness symptoms was reported, and it was not associated with changes in SIgA levels. In summary, a situation of combined stress for an important championship was found to decrease the level of SIgA-mediated immune protection at the mucosal surface in team members, with greater changes observed in the athletes.
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Pereira, G, Almeida, AG, Rodacki, ALF, Ugrinowitsch, C, Fowler, NE, Kokubun, E. The influence of resting period length on jumping performance. J Strength Cond Res 22: 1259-1264, 2008-The purpose of this study was to determine a resting interval between countermovement jumps (i.e., volleyball spikes) that allows the maintenance of maximal jumping performance. Ten male volleyball players (1.85 +/- 0.05 m, 77.2 +/- 10.6 kg, 21.6 +/- 5.3 years) performed 6 experimental jumping sessions. In the first and sixth sessions, maximal countermovement jump height was measured, followed by submaximal countermovement jumps to the point of volitional fatigue. The number of countermovement jumps was used as a reference to test the effect of rest period between volleyball spikes. From the second to fifth experimental sessions, 30 maximal volleyball spikes were performed with different resting periods (i.e., 8, 14, 17, and 20 seconds) followed by countermovement jumps. Between the 15th and 30th spikes, the blood lactate concentration and heart rate were measured. Because the performance on the first and sixth sessions was the same, no training effects were noticed. During the 8-second resting interval set, the lactate concentration increased significantly between the 15th and 30th spikes (i.e., from 3.37 +/- 1.16 mmol to 4.94 +/- 1.49 mmol); the number of countermovement jumps decreased significantly after spikes compared to those performed without a previous effort (i.e., from 23 +/- 7 jumps to 17 +/- 9 jumps); and these variables were significantly correlated (r = -0.7). On the other hand, the lactate concentration and number of countermovement jumps were stable across the other resting intervals, without a heart rate steady state. The results indicate that an adequate resting period between spikes allowed participants to achieve a lactate steady state in which the performance was maintained during the exercise. These findings show that resting intervals between 14 and 17 seconds, typical during volleyball matches, are indicated to use in volleyball spike drills due to their capacity to maintain maximal jumping performance.
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Mixed martial arts (MMA) have become a fast-growing worldwide expansion of martial arts competition, requiring high level of skill, physical conditioning, and strategy, and involving a synthesis of combat while standing or on the ground. This study quantified the effort-pause ratio (EP), and classified effort segments of stand-up or groundwork development to identify the number of actions performed per round in MMA matches. 52 MMA athletes participated in the study (M age = 24 yr., SD = 5; average experience in MMA = 5 yr., SD = 3). A one-way analysis of variance with repeated measurements was conducted to compare the type of action across the rounds. A chi-squared test was applied across the percentages to compare proportions of different events. Only one significant difference (p < .05) was observed among rounds: time in groundwork of low intensity was longer in the second compared to the third round. When the interval between rounds was not considered, the EP ratio (between high-intensity effort to low-intensity effort plus pauses) WE S 1:2 to 1:4. This ratio is between ratios typical for judo, wrestling, karate, and taekwondo and reflects the combination of ground and standup techniques. Most of the matches ended in the third round, involving high-intensity actions, predominantly executed during groundwork combat.
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The concentration of hydrogen peroxide is an important parameter in the azo dyes decoloration process through the utilization of advanced oxidizing processes, particularly by oxidizing via UV/H2O2. It is pointed out that, from a specific concentration, the hydrogen peroxide works as a hydroxyl radical self-consumer and thus a decrease of the system`s oxidizing power happens. The determination of the process critical point (maximum amount of hydrogen peroxide to be added) was performed through a ""thorough mapping"" or discretization of the target region, founded on the maximization of an objective function objective (constant of reaction kinetics of pseudo-first order). The discretization of the operational region occurred through a feedforward backpropagation neural model. The neural model obtained presented remarkable coefficient of correlation between real and predicted values for the absorbance variable, above 0.98. In the present work, the neural model had, as phenomenological basis the Acid Brown 75 dye decoloration process. The hydrogen peroxide addition critical point, represented by a value of mass relation (F) between the hydrogen peroxide mass and the dye mass, was established in the interval 50 < F < 60. (C) 2007 Elsevier B.V. All rights reserved.