Roger A. Pierson

Bio: Roger A. Pierson is an academic researcher from University of Saskatchewan. The author has contributed to research in topics: Follicular phase & Ovulation. The author has an hindex of 60, co-authored 242 publications receiving 10129 citations. Previous affiliations of Roger A. Pierson include University of Wisconsin-Madison & Royal University Hospital.

Updated ultrasound criteria for polycystic ovary syndrome: reliable thresholds for elevated follicle population and ovarian volume

Abstract: main results: Diagnostic potential for PCOS was highest for FNPO (0.969), followed by FNPS (0.880) and OV (0.873) as judged by the area under the ROC curve. An FNPO threshold of 26 follicles had the best compromise between sensitivity (85%) and specificity (94%) when discriminating between controls and PCOS. Similarly, an FNPS threshold of nine follicles had a 69% sensitivity and 90% specificity, and an OV of 10 cm 3 had a 81% sensitivity and 84% specificity. Levels of intra-observer reliability were 0.81, 0.80 and 0.86 when assessing FNPO, FNPS and OV, respectively. Inter-observer reliability was 0.71, 0.72 and 0.82, respectively.

Ovarian antral folliculogenesis during the human menstrual cycle: a review

Abstract: BACKGROUND Ovarian follicles undergo dynamic morphologic and endocrinologic changes during the human menstrual cycle. The physiologic mechanisms underlying recruitment and selection of antral follicles in women are not fully elucidated. METHODS A comprehensive review of >200 studies was conducted using PubMed. The objective was to compare and contrast different perspectives on human antral folliculogenesis. RESULTS Antral folliculogenesis has been studied using histologic, endocrinologic and/or ultrasonographic techniques. Different theories of antral follicle recruitment include: (i) continuous recruitment throughout the menstrual cycle; (ii) recruitment of a 'cohort' of antral follicles once in the late-luteal phase or early-follicular phase of each cycle and (iii) recruitment of two or three 'cohorts' or 'waves' during each cycle. Generally, a single dominant follicle is selected in the mid-follicular phase of each cycle and this follicle ovulates at mid-cycle. However, a dominant follicle may also be selected during anovulatory waves that precede the ovulatory wave in some women. CONCLUSIONS There is increasing evidence to indicate that multiple waves of antral follicles develop during the human menstrual cycle. Ovarian follicular waves in women are comparable with those documented in several animal species; however, species-specific differences exist. Enhancing our understanding of the endocrine and paracrine mechanisms underlying antral follicular wave dynamics has clinical implications for understanding age-related changes in reproductive function, optimizing hormonal contraceptive and ovarian stimulation regimens and identifying non-invasive markers of the physiologic status of follicles which are predictive of oocyte competence and assisted reproduction outcomes.

Characterization of Ovarian Follicular Wave Dynamics in Women

Abstract: A wave phenomenon of ovarian follicular development in women has recently been documented in our laboratory. The objective of the present study was to characterize follicular waves to determine whether women exhibit major and minor wave patterns of follicle development during the interovulatory interval (IOI). The ovaries of 50 women with clinically normal menstrual cycles were examined daily using transvaginal ultrasonography for one IOI. Profiles of the diameters of all follicles ≥4 mm and the numbers of follicles ≥5 mm were graphed during the IOI. Major waves were defined as those in which one follicle grew to ≥10 mm and exceeded all other follicles by ≥2 mm. Minor waves were defined as those in which follicles developed to a diameter of <10 mm and follicle dominance was not manifest. Blood samples were drawn to measure serum concentrations of estradiol-17β, LH, and FSH. Women exhibited major and minor patterns of follicular wave dynamics during the IOI. Of the 50 women evaluated, 29/34 women ...

Principles of Neural Science

Abstract: I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Decision aids for people facing health treatment or screening decisions

Abstract: Background Decision aids are intended to help people participate in decisions that involve weighing the benefits and harms of treatment options often with scientific uncertainty. Objectives To assess the effects of decision aids for people facing treatment or screening decisions. Search methods For this update, we searched from 2009 to June 2012 in MEDLINE; CENTRAL; EMBASE; PsycINFO; and grey literature. Cumulatively, we have searched each database since its start date including CINAHL (to September 2008). Selection criteria We included published randomized controlled trials of decision aids, which are interventions designed to support patients' decision making by making explicit the decision, providing information about treatment or screening options and their associated outcomes, compared to usual care and/or alternative interventions. We excluded studies of participants making hypothetical decisions. Data collection and analysis Two review authors independently screened citations for inclusion, extracted data, and assessed risk of bias. The primary outcomes, based on the International Patient Decision Aid Standards (IPDAS), were: A) 'choice made' attributes; B) 'decision-making process' attributes. Secondary outcomes were behavioral, health, and health-system effects. We pooled results using mean differences (MD) and relative risks (RR), applying a random-effects model. Main results This update includes 33 new studies for a total of 115 studies involving 34,444 participants. For risk of bias, selective outcome reporting and blinding of participants and personnel were mostly rated as unclear due to inadequate reporting. Based on 7 items, 8 of 115 studies had high risk of bias for 1 or 2 items each. Of 115 included studies, 88 (76.5%) used at least one of the IPDAS effectiveness criteria: A) 'choice made' attributes criteria: knowledge scores (76 studies); accurate risk perceptions (25 studies); and informed value-based choice (20 studies); and B) 'decision-making process' attributes criteria: feeling informed (34 studies) and feeling clear about values (29 studies). A) Criteria involving 'choice made' attributes: Compared to usual care, decision aids increased knowledge (MD 13.34 out of 100; 95% confidence interval (CI) 11.17 to 15.51; n = 42). When more detailed decision aids were compared to simple decision aids, the relative improvement in knowledge was significant (MD 5.52 out of 100; 95% CI 3.90 to 7.15; n = 19). Exposure to a decision aid with expressed probabilities resulted in a higher proportion of people with accurate risk perceptions (RR 1.82; 95% CI 1.52 to 2.16; n = 19). Exposure to a decision aid with explicit values clarification resulted in a higher proportion of patients choosing an option congruent with their values (RR 1.51; 95% CI 1.17 to 1.96; n = 13). B) Criteria involving 'decision-making process' attributes: Decision aids compared to usual care interventions resulted in: a) lower decisional conflict related to feeling uninformed (MD -7.26 of 100; 95% CI -9.73 to -4.78; n = 22) and feeling unclear about personal values (MD -6.09; 95% CI -8.50 to -3.67; n = 18); b) reduced proportions of people who were passive in decision making (RR 0.66; 95% CI 0.53 to 0.81; n = 14); and c) reduced proportions of people who remained undecided post-intervention (RR 0.59; 95% CI 0.47 to 0.72; n = 18). Decision aids appeared to have a positive effect on patient-practitioner communication in all nine studies that measured this outcome. For satisfaction with the decision (n = 20), decision-making process (n = 17), and/or preparation for decision making (n = 3), those exposed to a decision aid were either more satisfied, or there was no difference between the decision aid versus comparison interventions. No studies evaluated decision-making process attributes for helping patients to recognize that a decision needs to be made, or understanding that values affect the choice. C) Secondary outcomes Exposure to decision aids compared to usual care reduced the number of people of choosing major elective invasive surgery in favour of more conservative options (RR 0.79; 95% CI 0.68 to 0.93; n = 15). Exposure to decision aids compared to usual care reduced the number of people choosing to have prostate-specific antigen screening (RR 0.87; 95% CI 0.77 to 0.98; n = 9). When detailed compared to simple decision aids were used, fewer people chose menopausal hormone therapy (RR 0.73; 95% CI 0.55 to 0.98; n = 3). For other decisions, the effect on choices was variable. The effect of decision aids on length of consultation varied from 8 minutes shorter to 23 minutes longer (median 2.55 minutes longer) with 2 studies indicating statistically-significantly longer, 1 study shorter, and 6 studies reporting no difference in consultation length. Groups of patients receiving decision aids do not appear to differ from comparison groups in terms of anxiety (n = 30), general health outcomes (n = 11), and condition-specific health outcomes (n = 11). The effects of decision aids on other outcomes (adherence to the decision, costs/resource use) were inconclusive. Authors' conclusions There is high-quality evidence that decision aids compared to usual care improve people's knowledge regarding options, and reduce their decisional conflict related to feeling uninformed and unclear about their personal values. There is moderate-quality evidence that decision aids compared to usual care stimulate people to take a more active role in decision making, and improve accurate risk perceptions when probabilities are included in decision aids, compared to not being included. There is low-quality evidence that decision aids improve congruence between the chosen option and the patient's values. New for this updated review is further evidence indicating more informed, values-based choices, and improved patient-practitioner communication. There is a variable effect of decision aids on length of consultation. Consistent with findings from the previous review, decision aids have a variable effect on choices. They reduce the number of people choosing discretionary surgery and have no apparent adverse effects on health outcomes or satisfaction. The effects on adherence with the chosen option, cost-effectiveness, use with lower literacy populations, and level of detail needed in decision aids need further evaluation. Little is known about the degree of detail that decision aids need in order to have a positive effect on attributes of the choice made, or the decision-making process.

Image Processing

Abstract: MUCKE aims to mine a large volume of images, to structure them conceptually and to use this conceptual structuring in order to improve large-scale image retrieval. The last decade witnessed important progress concerning low-level image representations. However, there are a number problems which need to be solved in order to unleash the full potential of image mining in applications. The central problem with low-level representations is the mismatch between them and the human interpretation of image content. This problem can be instantiated, for instance, by the incapability of existing descriptors to capture spatial relationships between the concepts represented or by their incapability to convey an explanation of why two images are similar in a content-based image retrieval framework. We start by assessing existing local descriptors for image classification and by proposing to use co-occurrence matrices to better capture spatial relationships in images. The main focus in MUCKE is on cleaning large scale Web image corpora and on proposing image representations which are closer to the human interpretation of images. Consequently, we introduce methods which tackle these two problems and compare results to state of the art methods. Note: some aspects of this deliverable are withheld at this time as they are pending review. Please contact the authors for a preview.

Robot vision

Abstract: A scheme is developed for classifying the types of motion perceived by a humanlike robot. It is assumed that the robot receives visual images of the scene using a perspective system model. Equations, theorems, concepts, clues, etc., relating the objects, their positions, and their motion to their images on the focal plane are presented. >