What is the body temperature response of healthy pregnant women exercising at moderate intensity ... more What is the body temperature response of healthy pregnant women exercising at moderate intensity in an aqua-aerobics class where the water temperature is in the range of 28 to 33 degrees Celsius, as typically found in community swimming pools? An observational study. One hundred and nine women in the second and third trimester of pregnancy who were enrolled in a standardised aqua-aerobics class. Tympanic temperature was measured at rest pre-immersion (T1), after 35minutes of moderate-intensity aqua-aerobic exercise (T2), after a further 10minutes of light exercise while still in the water (T3) and finally on departure from the facility (T4). The range of water temperatures in seven indoor community pools was 28.8 to 33.4 degrees Celsius. Body temperature increased by a mean of 0.16 degrees Celsius (SD 0.35, p<0.001) at T2, was maintained at this level at T3 and had returned to pre-immersion resting values at T4. Regression analysis demonstrated that the temperature response was n...
Despite evidence of an increased fall risk in people with chronic obstructive pulmonary disease (... more Despite evidence of an increased fall risk in people with chronic obstructive pulmonary disease (COPD), there is a paucity of prospective fall data in this population. This preliminary study aimed to prospectively examine the prevalence rate, incidence rate and associated risk factors for falls in a sample of community-dwelling people with COPD over 1 year. Forty-one participants with stable COPD (mean ± SD) aged 71 ± 8 years with a forced expiratory volume in 1 s of 45.1 ± 16.2% predicted were included. At baseline, participants' demographic, physical function and fall-related measures were documented. Falls were monitored for 12 months following initial assessments. The prevalence of people having falls was 40% (95% CI: 24-56%); amongst these, 75% had frequent falls. The overall fall incidence rate was 1.17 falls/person-year. Risk factors associated with a higher fall incidence rate ratio (IRR) in COPD were: number of pack-years (IRR: 1.02; 95%CI: 1.00,1.04), comorbidities (IR...
Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important ... more Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery. In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE). Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e' and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and…
OBJECTIVE: To investigate forelimb hoof wall strains and shape changes in unshod horses undergoin... more OBJECTIVE: To investigate forelimb hoof wall strains and shape changes in unshod horses undergoing regular moderate exercise on a treadmill at selected speeds and gaits.ANIMALS: 6 horses of various body types.PROCEDURES: Each horse was exercised on a treadmill (walking, trotting, and cantering, with or without galloping at 12.5 m/s) 3 times a week for 4 consecutive weeks; duration of each exercise session ranged from 10 to 14 minutes. During the 4-week period, the proximal hoof circumference (PHC) and toe angle (TA) of each forelimb hoof were measured weekly with a flexible measuring tape and a hoof gauge, respectively. Forelimb hoof wall strains were measured bilaterally at the toe and each quarter (3 strain gauges) immediately before the first and after the last exercise session.RESULTS: Strain measurements revealed a consistent pattern of deformation of the hoof wall in both forelimbs at all gaits; strains increased during the stance phase of the stride. Strain values were dependent on site and gait. Compared with initial findings, mean TA increased significantly, whereas mean PHC did not, after the 4-week exercise period. A relationship between TA changes and hoof wall strains could not be established.CONCLUSIONS AND CLINICAL RELEVANCE: In unshod horses, forelimb hoof wall strains were affected by site and gait, but not by discrete changes in TA; PHC did not change in response to moderate regular exercise. The pattern of hoof loading was consistent despite significant changes in TA.
Data mining (and knowledge discovery) is the art and science of finding useful and valid patterns... more Data mining (and knowledge discovery) is the art and science of finding useful and valid patterns in data.
An important aspect of multiple hypothesis testing is controlling the significance level, or the ... more An important aspect of multiple hypothesis testing is controlling the significance level, or the level of Type I error. When the test statistics are not independent it can be particularly challenging to deal with this problem, without resorting to very conservative procedures. In this paper we show that, in the context of contemporary multiple testing problems, where the number of tests is often very large, the difficulties caused by dependence are less serious than in classical cases. This is particularly true when the null distributions of test statistics are relatively light-tailed, for example, when they can be based on Normal or Student's t approximations. There, if the test statistics can fairly be viewed as being generated by a linear process, an analysis founded on the incorrect assumption of independence is asymptotically correct as the number of hypotheses diverges. In particular, the point process representing the null distribution of the indices at which statistically significant test results occur is approximately Poisson, just as in the case of independence. The Poisson process also has the same mean as in the independence case, and of course exhibits no clustering of false discoveries. However, this result can fail if the null distributions are particularly heavy-tailed. There clusters of statistically significant results can occur, even when the null hypothesis is correct. We give an intuitive explanation for these disparate properties in light-and heavy-tailed cases, and provide rigorous theory underpinning the intuition.
What is the body temperature response of healthy pregnant women exercising at moderate intensity ... more What is the body temperature response of healthy pregnant women exercising at moderate intensity in an aqua-aerobics class where the water temperature is in the range of 28 to 33 degrees Celsius, as typically found in community swimming pools? An observational study. One hundred and nine women in the second and third trimester of pregnancy who were enrolled in a standardised aqua-aerobics class. Tympanic temperature was measured at rest pre-immersion (T1), after 35minutes of moderate-intensity aqua-aerobic exercise (T2), after a further 10minutes of light exercise while still in the water (T3) and finally on departure from the facility (T4). The range of water temperatures in seven indoor community pools was 28.8 to 33.4 degrees Celsius. Body temperature increased by a mean of 0.16 degrees Celsius (SD 0.35, p<0.001) at T2, was maintained at this level at T3 and had returned to pre-immersion resting values at T4. Regression analysis demonstrated that the temperature response was n...
Despite evidence of an increased fall risk in people with chronic obstructive pulmonary disease (... more Despite evidence of an increased fall risk in people with chronic obstructive pulmonary disease (COPD), there is a paucity of prospective fall data in this population. This preliminary study aimed to prospectively examine the prevalence rate, incidence rate and associated risk factors for falls in a sample of community-dwelling people with COPD over 1 year. Forty-one participants with stable COPD (mean ± SD) aged 71 ± 8 years with a forced expiratory volume in 1 s of 45.1 ± 16.2% predicted were included. At baseline, participants' demographic, physical function and fall-related measures were documented. Falls were monitored for 12 months following initial assessments. The prevalence of people having falls was 40% (95% CI: 24-56%); amongst these, 75% had frequent falls. The overall fall incidence rate was 1.17 falls/person-year. Risk factors associated with a higher fall incidence rate ratio (IRR) in COPD were: number of pack-years (IRR: 1.02; 95%CI: 1.00,1.04), comorbidities (IR...
Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important ... more Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery. In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE). Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e' and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and…
OBJECTIVE: To investigate forelimb hoof wall strains and shape changes in unshod horses undergoin... more OBJECTIVE: To investigate forelimb hoof wall strains and shape changes in unshod horses undergoing regular moderate exercise on a treadmill at selected speeds and gaits.ANIMALS: 6 horses of various body types.PROCEDURES: Each horse was exercised on a treadmill (walking, trotting, and cantering, with or without galloping at 12.5 m/s) 3 times a week for 4 consecutive weeks; duration of each exercise session ranged from 10 to 14 minutes. During the 4-week period, the proximal hoof circumference (PHC) and toe angle (TA) of each forelimb hoof were measured weekly with a flexible measuring tape and a hoof gauge, respectively. Forelimb hoof wall strains were measured bilaterally at the toe and each quarter (3 strain gauges) immediately before the first and after the last exercise session.RESULTS: Strain measurements revealed a consistent pattern of deformation of the hoof wall in both forelimbs at all gaits; strains increased during the stance phase of the stride. Strain values were dependent on site and gait. Compared with initial findings, mean TA increased significantly, whereas mean PHC did not, after the 4-week exercise period. A relationship between TA changes and hoof wall strains could not be established.CONCLUSIONS AND CLINICAL RELEVANCE: In unshod horses, forelimb hoof wall strains were affected by site and gait, but not by discrete changes in TA; PHC did not change in response to moderate regular exercise. The pattern of hoof loading was consistent despite significant changes in TA.
Data mining (and knowledge discovery) is the art and science of finding useful and valid patterns... more Data mining (and knowledge discovery) is the art and science of finding useful and valid patterns in data.
An important aspect of multiple hypothesis testing is controlling the significance level, or the ... more An important aspect of multiple hypothesis testing is controlling the significance level, or the level of Type I error. When the test statistics are not independent it can be particularly challenging to deal with this problem, without resorting to very conservative procedures. In this paper we show that, in the context of contemporary multiple testing problems, where the number of tests is often very large, the difficulties caused by dependence are less serious than in classical cases. This is particularly true when the null distributions of test statistics are relatively light-tailed, for example, when they can be based on Normal or Student's t approximations. There, if the test statistics can fairly be viewed as being generated by a linear process, an analysis founded on the incorrect assumption of independence is asymptotically correct as the number of hypotheses diverges. In particular, the point process representing the null distribution of the indices at which statistically significant test results occur is approximately Poisson, just as in the case of independence. The Poisson process also has the same mean as in the independence case, and of course exhibits no clustering of false discoveries. However, this result can fail if the null distributions are particularly heavy-tailed. There clusters of statistically significant results can occur, even when the null hypothesis is correct. We give an intuitive explanation for these disparate properties in light-and heavy-tailed cases, and provide rigorous theory underpinning the intuition.
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Papers by Sandy Clarke