A Consideration of Alternative Sample Spaces Used in Coin-Toss Problems.

This paper examines coin-toss comparison questions from two recent studies involving undergraduate students and high school teachers and connects to findings from two prior studies in the literature. Considering possible sample spaces employed by participants, this is a reflection on whether one sequence could be more likely depending on the interpretation of the question. To critique the choice of sequences and determine possible scenarios in which one sequence may be more likely than the other, three alternative sample spaces were explored. It was determined that different sample spaces can lead to one sequence being more likely to occur than the other. Further evaluation discusses whether alternative sample spaces may have been utilised by the participants in each of the studies, and hence, the paper concludes with an advocacy to enquire deeper into participants' reasoning when investigating coin-toss questions.

Cet article s'intéresse aux aspects liés à la comparaison de tirages au sort dans deux études récentes menées auprès d'étudiants de premier cycle et d'enseignants au secondaire et nous établissons des liens avec les conclusions de deux études antérieures consultées dans la documentation. En tenant compte des espaces échantillon potentiels utilisés par les participants, cet article amène une réflexion à savoir si une séquence peut s'avérer plus probable selon l'interprétation faite de la question. Afin d'évaluer le bien-fondé des séquences choisies et pour déterminer les scénarios possibles dans lesquels une séquence serait plus susceptible d'être présente qu'une autre, nous avons exploré trois espaces échantillon différents. On a jugé que des espaces échantillon distincts peuvent donner matière à ce qu'une séquence est davantage susceptible de se matérialiser qu'une autre. La suite de l'évaluation porte sur la question de savoir si des espaces échantillon différents peuvent avoir été utilisés par les participants dans chacune des études et de ce fait, la conclusion de l'article revendique un examen plus approfondi du raisonnement des participants lorsque l'on étudie des questions liées au tirage au sort.

Assessing exercises recommended for women at risk of pelvic floor disorders using multivariate statistical techniques.

INTRODUCTION AND HYPOTHESIS: There is a widely held, but untested, belief that certain exercises and activities generate intraabdominal pressure (IAP) that may compromise the function of the pelvic floor muscles. Women with, or at risk of, pelvic floor disorders are advised therefore to refrain from these exercises and activities in order to theoretically protect their pelvic floor. The aim of this study was to compare IAPs generated during exercises of different types that are recommended to women as pelvic floor "safe" with those generated during the corresponding conventional exercises that women are typically cautioned against. METHODS: This was a cross-sectional cohort study. All participants were guided by a trained exercise practitioner through a series of ten exercise pairs, one version recommended to women as pelvic floor "safe" and one conventional version which women are cautioned against. IAP components were extracted from the pressure traces from a wireless intravaginal pressure sensor and used in multivariate linear regression modelling, canonical discriminant analysis, and linear mixed modelling. RESULTS: A total of 53 participants were recruited. After adjusting for age, body mass index and parity, there was an exercise type-version effect (p < 0.01). After taking into account all pressure components of the IAP trace, there was a significant difference in IAP between the recommended and discouraged versions of the same exercise for five of the ten exercise types. Coughing and the Valsalva manoeuvre generated IAPs that were distinct from those generated by the exercises. CONCLUSIONS: No differences in IAPs were found between the recommended and discouraged versions of the same exercise for all exercise types. In particular, the IAPs generated during the two versions of ball rotations, lunges, core, push-ups and squats did not differ significantly. Performing the recommended pelvic floor "safe" version instead of the discouraged conventional version of these exercises may not necessarily protect the pelvic floor and vice versa.

Effects of lipid emulsion particle size on satiety and energy intake: a randomised cross-over trial.

BACKGROUND/OBJECTIVES: Emulsified lipids, with central lipid core surrounded by polar lipid 'protective coat', have been proposed to stimulate the ileal brake, alter appetite, food intake and aid weight control. In addition to lipid composition, emulsion particle size may contribute to efficacy with small droplets providing a larger surface area for gastrointestinal (GI) lipase action and larger droplets prolonging and delaying digestion in the GI tract. Tube feeding studies delivering emulsions directly into the small intestine show clear effects of smaller particle size on appetite and food intake, but evidence from oral feeding studies is sparse. The objective of this study was to determine the effects of lipid emulsion particle size on appetite response and food intake. SUBJECTS/METHODS: In a three-arm randomised cross-over, high-phospholipid (PL) dairy lipid emulsions or matched control were consumed at breakfast within a yoghurt smoothie: (i) large-particle size emulsion, LPE (diameter 0.759 µm, 10 g lipid emulsion, 190 g yoghurt), (ii) small-particle size emulsion, SPE (diameter 0.290 µm, 10 g lipid emulsion, 190 g yoghurt), (iii) control non-emulsion, NE (10 g non-emulsion lipid, 190 g yoghurt). Twenty male participants completed the study, where postprandial appetite response was rated using visual analogue scales (VAS) and ad libitum energy intake at a lunch meal measured 3 h later. RESULTS: There was a trend for LPE to suppress hunger (P = 0.08) and enhance fullness (P = 0.24) relative to both SPE and NE but not statistically significant, and no significant effect of either emulsion on food intake at the lunch meal (P > 0.05). CONCLUSIONS: Altering particle size of a high-PL emulsion did not enhance satiety or alter eating behaviour in a group of lean men.

Duodenal and ileal glucose infusions differentially alter gastrointestinal peptides, appetite response, and food intake: a tube feeding study.

Background: Activation of the ileal brake through the delivery of nutrients into the distal small intestine to promote satiety and suppress food intake provides a new target for weight loss. Evidence is limited, with support from naso-ileal lipid infusion studies.Objective: The objective of the study was to investigate whether glucose infused into the duodenum and ileum differentially alters appetite response, food intake, and secretion of satiety-related gastrointestinal peptides.Design: Fourteen healthy male participants were randomly assigned to a blinded 4-treatment crossover, with each treatment of single-day duration. On the day before the intervention (day 0), a 380-cm multilumen tube (1.75-mm diameter) with independent port access to the duodenum and ileum was inserted, and position was confirmed by X-ray. Subsequently (days 1-4), a standardized breakfast meal was followed midmorning by a 90-min infusion of isotonic glucose (15 g, 235 kJ) or saline to the duodenum or ileum. Appetite ratings were assessed with the use of visual analog scales (VASs), blood samples collected, and ad libitum energy intake (EI) measured at lunch, afternoon snack, and dinner.Results: Thirteen participants completed the 4 infusion days. There was a significant effect of nutrient infused and site (treatment × time, P < 0.05) such that glucose-to-ileum altered VAS-rated fullness, satisfaction, and thoughts of food compared with saline-to-ileum (Tukey's post hoc, P < 0.05); decreased ad libitum EI at lunch compared with glucose-to-duodenum [-22%, -988 ± 379 kJ (mean ± SEM), Tukey's post hoc, P < 0.05]; and increased glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) compared with all other treatments (Tukey's post hoc, P < 0.05).Conclusions: Macronutrient delivery to the proximal and distal small intestine elicits different outcomes. Glucose infusion to the ileum increased GLP-1 and PYY secretion, suppressed aspects of VAS-rated appetite, and decreased ad libitum EI at a subsequent meal. Although glucose to the duodenum also suppressed appetite ratings, eating behavior was not altered. This trial was registered at www.anzctr.org.au as ACTRN12612000429853.

Characterizing levator-ani muscle stiffness pre- and post-childbirth in European and Polynesian women in New Zealand: a pilot study.

INTRODUCTION: The influence of levator-ani muscles on second-stage labor is poorly understood. The ability of these muscles to stretch without damage may affect birth outcomes, but little is known about material properties, effects of pregnancy and/or ethnicity on levator-ani stiffness. There are strong associations between muscle damage and subsequent pelvic floor disorders. This study aimed to quantify levator-ani muscle stiffness during the third trimester of pregnancy and postpartum in European and Polynesian women. Associations between stiffness, obstetric variables, and the risk of intrapartum levator-ani injury (avulsion) were investigated. MATERIAL AND METHODS: This was a prospective observational pilot study. A total of 167 (106 European and 61 Polynesian) nulliparous women were recruited antenatally; 129 returned postnatally. Participants were assessed between 36 and 38 weeks' gestation and three to five months postpartum. Assessments included pelvic floor ultrasound, elastometry testing, and validated questionnaires on pelvic floor function. Logistic regression, Student t-, Chi-square and Mann-Whitney tests were used as appropriate. RESULTS: There are significant differences between antenatal and postnatal muscle stiffness measurements (p < 0.01). Stiffness was significantly higher in the European cohort (p = 0.03). There were more avulsion injuries in European (20%) than in Polynesian (9%) women. There were no significant differences in antenatal stiffness between women with and without avulsion, but change in stiffness (antenatal to postnatal) was significantly less in the avulsion group. There were no associations between stiffness, and other obstetric variables, epidural anesthesia seemed protective (p = 0.03). CONCLUSIONS: Quantification of levator-ani muscle stiffness is feasible. Muscle stiffness is significantly different before and after birth.

Postprandial effects of a polyphenolic grape extract (PGE) supplement on appetite and food intake: a randomised dose-comparison trial.

BACKGROUND: There is recent evidence that glucose delivered to the distal small intestine (SI) may stimulate the ileal brake and inhibit appetite. High polyphenolic grape extract (PGE) has been shown to inhibit α-amylase and α-glucosidase activity, two key enzymes required for starch digestion, in vitro. It is hypothesised to slow digestion and absorption of starch in the proximal SI such that glucose may be delivered distally into the ileum and suppress appetite. This study investigated the safety and efficacy of a PGE supplement, delivered within a capsule and consumed with a high-starch breakfast, on appetite ratings and ad libitum energy intake (EI) at a subsequent lunch meal. METHODS: Twenty healthy, non-obese (BMI 18-28 kg/m(2)) male volunteers participated in a randomised, double blind, placebo controlled, three arm, cross-over study. Participants were administered (i) low dose PGE500 (500 mg), (ii) high dose PGE1500 (1500 mg), and (iii) matched placebo with a 2 MJ high-starch breakfast (white bread); followed 3 h later by a single item buffet-style lunch meal (pasta and meat sauce). Outcome variables were feelings of hunger, fullness, prospective thoughts of food (TOF) and satisfaction assessed using visual analogue scales (VAS); and ad lib energy and macronutrient intake at the lunch meal. RESULTS: There was no detectable effect of PGE500 or PGE1500 compared with placebo (all, time*supplement interaction, P > 0.05) on VAS-assessed hunger, fullness, TOF or satisfaction. There was also no evidence that PGE significantly altered ad lib energy or macronutrient intake at the lunch meal relative to placebo (P > 0.05). EI following PGE500 was +164 kJ higher than placebo (+5.3%, P > 0.05); and EI following PGE1500 was -51 kJ lower than placebo (-1.7%, P > 0.05). CONCLUSIONS: Whilst well tolerated, there was no evidence that encapsulated low dose PGE500 or high dose PGE1500 consumed with a high starch breakfast meal altered postprandial hunger, fullness, TOF or satisfaction relative to a matched placebo. Nor was there evidence that either dose altered ad lib energy or macronutrient intake at an outcome meal. TRIAL REGISTRATION: ACTRN12614000041651.

An automated hand-held elastometer for quantifying the passive stiffness of the levator ani muscle in women.

AIM: Design and develop an automated, hand-held instrument (elastometer) to assess in vivo passive stiffness of the pelvic floor muscle. MATERIALS AND METHODS: The elastometer system consisted of a hand piece, real-time controller, and laptop computer. A cable connected the hand-piece to the controller, which communicated with a laptop computer via an ethernet connection. Force sensitivity calibration and displacement accuracy were determined experimentally using a spring load and an Instron mechanical tester. A test re-test series quantified the in vivo repeatability (within a procedure) and reproducibility (between procedures after a 5 min delay) of passive stiffness in volunteers (n = 20). Stiffness was determined from the gradient of the force-displacement curve for each cycle. RESULTS: The force-aperture spring measurements from the elastometer showed consistent (r(2) = 1.0000) agreement with those measured by the Instron. The difference between spring stiffness as measured by the elastometer and the Instron (388.1 N/m cf. 388.5 N/m, respectively) was negligible. The intra-class correlation coefficient for repeatability within procedures was 0.986 95% CI (0.964-0.994) n = 20, and reproducibility between procedures ICC 0.934 (95% CI 0.779-0.981) n = 12. Bland-Altman analysis determined a bias of 0.3 and 18.5 N/m, for repeatability and reproducibility respectively. Neither bias is likely to be clinically significance. CONCLUSION: The elastometer demonstrated very good repeatability and accuracy in the measurement of force/displacement during in vitro testing. There was a high degree of repeatability and reproducibility in stiffness measurements in a test re-test series. Our results demonstrate the elastometer is accurate and reliable and thereby suitable for larger clinical trials.

Comparison between transperineal ultrasound and digital detection of levator ani trauma. Can we improve the odds?

AIMS: To investigate the predictive ability of four digital assessment parameters to detect levator ani (LA) muscle defects (avulsion injury) and compare these to transperineal tomographic ultrasound images. METHODS: This was an observational study imbedded in a larger quasi-experimental cohort study for women with urinary incontinence. Seventy-two women, ≥ 60 years who had attended or were going to attend physiotherapy for treatment of urinary incontinence, were included in the study. Inclusion criteria from the parent study were symptoms of stress, urge or both types of urinary incontinence. The predictive ability of the following digital parameters: direct palpation of a discontinuity of the LA muscle from insertion on the pubic ramus; palpation of the distance between the muscle insertion sites; palpation of LA strength; palpation of LA tone, were analyzed against findings from tomographic transperineal ultrasound images. Correlation between methods was measured using Cohen's kappa for each of the individual parameters. RESULTS: Seventeen women (24%) presented with a complete or partial avulsion of the puborectalis muscle as diagnosed with tomographic ultrasound imaging. Nine women (13%) had complete avulsions, one of which was bilateral. The predictive ability of the digital assessment parameters varied from poor (k = 0.187, 95% CI [0.02-0.36]) to moderate (k = 0.569, 95% CI [0.31-0.83]). The new parameter of 'width between insertion sites' performed best. CONCLUSIONS: Adding the parameter of "width between insertion sites" appears to enhance our ability to detect avulsion of the levator ani (LA) muscle by digital examination however it does not distinguish between unilateral or bilateral avulsion.

Using a smaller dining plate does not suppress food intake from a buffet lunch meal in overweight, unrestrained women.

The aim of the study was to determine whether plate size affects ad libitum energy intake (EI) at a buffet-style lunch in overweight, yet unrestrained women. Twenty overweight/obese (BMI=25-40 kg/m(2)) women attended two study visits, and were randomly assigned to small (19.5 cm) or large (26.5 cm) diameter plate size at a free choice lunch meal. At 9 am participants were given a small (0.5 MJ) breakfast, followed at 12 noon by the lunch meal from which they ate ad lib until comfortably full. Mean (SEM) EI at lunch was 3975 (239)kJ and 3901 (249) kJ respectively for small and large plate size. There was no detectable difference in EI between the two plate sizes (P>0.05). When in a raised state of hunger and offered a palatable buffet meal, altering the diameter of the dining plate onto which food was self-served did not significantly alter ad lib EI. We conclude there was no evidence that a smaller plate suppressed EI in a group of unrestrained, overweight women encouraged to eat to appetite from a wide choice of items. Whether plate size is a useful cue for portion size, and hence control of EI, in individuals actively restricting intake however remains possible, and requires investigation.

Sensitivity of ad libitum meals to detect changes in hunger. Restricted-item or multi-item testmeals in the design of preload appetite studies.

The aims of the study were to determine whether restricted single-item or multi-item testmeals are better able to detect prior changes in hunger and fullness when assessing ad libitum eating behaviour. Thirty male participants were given a low- (L(E), 0.5 MJ) or high-energy (H(E), 4.0 MJ) breakfast preload designed to induce or suppress hunger, followed 3h later by a restricted-item (R(I)) or multi-item (M(I)) testmeal. The R(I) testmeal comprised pasta+meat sauce, whilst the M(I) testmeal comprised pasta+meat sauce plus bread, chicken, ham, cheese, salad, cake and fruit. The four conditions were (i) L(E)/R(I); (ii) L(E)/M(I); (iii) H(E)/R(I); (iv) H(E)/M(I). Visual analogue scales (VAS) were used to rate appetite sensations and EI was measured at the lunch testmeal. As expected, increasing the energy content of the preload significantly altered VAS ratings and decreased EI at the testmeal. Following both L(E) and H(E) breakfasts, EI was lower at the R(I) (L(E)=4566 kJ, H(E)=3583 kJ) compared with the M(I) (L(E)=6142 kJ, H(E)=5149 kJ) testmeal. However, the compensatory decrease in EI in response to the H(E) breakfast was not significantly greater at the R(I) testmeal (R(I): -983 kJ, 28.1% compensation; M(I): -993 kJ, 28.4% compensation). In preload studies measuring EI, increasing the variety of an ad lib testmeal may not decrease the sensitivity to detect changes in hunger and fullness.

Low-dose whey protein-enriched water beverages alter satiety in a study of overweight women.

AIM: To determine the effect of low-dose whey protein-enriched water beverages on postprandial satiety and energy intake (EI). METHODS: Fifty overweight and mildly obese women were given 500 mL water-based beverages on 4 different occasions in a double blind, cross-over study. The beverages were reasonably matched for colour, flavour, sweetness and contained 0% (water control, 0 g, 8 kJ), 1% (5 g, 93 kJ), 2% (10 g, 178 kJ) and 4% (20 g, 348 kJ) whey protein by weight (ClearProtein8855™). Following a standard evening meal and breakfast, beverages were consumed 120 min before an ad libitum lunch at which EI was measured. Feelings associated with hunger and fullness were also measured using visual analogue scales (VAS). RESULTS: 46 participants completed all 4 beverage conditions. There was a significant effect of beverage preload on hunger (beverage×time; P=0.0074), where each of the 1%, 2% and 4% w/w protein beverages decreased hunger compared to the water control (P<0.05). Suppression of hunger was also maintained for longer following the protein beverages (Friedman test, P=0.013). Fullness (beverage×time; P=0.0020) and satisfaction (beverage×time; P=0.0356) were both increased by the 1% and 4% protein beverages (P<0.05). EI at lunch decreased by up to 8 percent (control vs 4% protein, delta=-247 kJ, Tukey's post hoc, P>0.05) when escalating protein doses were added to the water preload (water control, 3028 kJ; 1%, 3080 kJ; 2%, 2924 kJ; 4%, 2781 kJ), only partial compensation for the added energy. CONCLUSIONS: These low-dose, whey protein-enriched water beverages significantly altered short term postprandial satiety, however the effect was not sufficient to impact on food intake when assessed 2 h after consumption.