Alphas, betas and skewy distributions: two ways of getting the wrong answer

Although many parametric statistical tests are considered to be robust, as recently shown in Methodologist’s Corner, it still pays to be circumspect about the assumptions underlying statistical tests. In this paper I show that robustness mainly refers to α, the type-I error. If the underlying distribution of data is ignored there can be a major penalty in terms of the β, the type-II error, representing a large increase in false negative rate or, equivalently, a severe loss of power of the test

Do study circles and a nutritional care policy improve nutritional care in a short- and long-term perspective in special accommodations?

Background: Disease-related malnutrition is a major health problem in the elderly population and management issues are under-explored. Objectives: What is the prevalence of undernutrition-risk (UN-risk), underweight, and overweight in special accommodations (SAs)? Do study circles and a nutritional care policy (NCP) improve the precision in nutritional care (NC) and decrease the prevalence of under- and overweight in a short- and/or long-term perspective?Design: Quasi-experimental pre- and post-intervention design with three experimental groups and one control group (CG). Setting: SAs. Participants: In 2005 (Time 1 – T1), 1726 (90.4%) residents agreed to participate; in 2007 (Time 2 – T2), 1,526 (81.8%); and in 2009 (Time 3 – T3), 1,459 (81.3%) residents participated. Interventions: Experimental groups: between T1 and T2 the first period of study circles was conducted in one municipality; between T2 and T3 a second period of study circles in another municipality was conducted; after T1 a NCP was implemented in one municipality. CG: residents in three municipalities. Measurements: Under- and overweight were defined based on BMI. Risk of undernutrition was defined as involving any of: involuntary weight loss, low BMI, and/or eating difficulties. The ‘precision in NC’ describes the relationship between nutritional treatment (protein- and energy-enriched food (PE-food) and/or oral supplements) and UN-risk. Results: The prevalence of UN-risk varied between 64 and 66%, underweight between 25 and 30%, and overweight between 30 and 33% in T1–T3. At T2 the prevalence of underweight was significantly lower in the first period study circle municipality, and at T3 in the second period study circle municipality compared to in the CG. The precision in NC was higher in a short-term perspective in the study circle municipalities and both in a short- and long-term perspective in the NCP municipality. At T3 between 54 and 70% of residents at UN-risk did not receive PE-food or oral supplements. Conclusions: Study circles give positive short-term effects and a NCP gives positive short- and long-term effects on NC. Whether a combination of study circles and the implementation of a NCP can give even better results is an area for future studies

PENERAPAN PROJECT BASED LEARNING MODEL MELALUI KARYA SENI PERTUNJUKAN PADA KELOMPOK PETUALANG BELAJAR SEMI PALAR BANDUNG

Individu dalam proses pembelajarannya memiliki cara yang berbeda untuk mengembangkan berbagai kecerdasan yang ada dalam dirinya. Pada dasarnya, setiap peserta didik memiliki potensi dan minat untuk dikembangkan dalam menempuh pendidikannya sesuai kompetensi yang dimiliki. Tujuan penulisan ini adalah untuk mendeskripsikan bagaimana cara belajar Kelompok Petualang Belajar, membuat rancangan desain project based learning model melalui karya seni pertunjukan, mengimplementasikan rancangan, serta melakukan evaluasi terhadap keseluruhan proses dan hasil kegiatan seni berupa kreasi dan apresiasi. Penelitian ini dapat menjadi sebuah topik untuk diangkat dalam penelitian ilmiah. Dimana, peranan guru bukan semata-mata mengimplementasikan kurikulum saja melainkan mampu menafsirkan kata-kata dalam kurikulum yang bersifat normatif. Dengan kata lain, peranan guru disini harus menjadi pelaku yang kreatif dan interpretatif. Adapun penerapan model pembelajaran pada kelompok petualang belajar menjadi salah satu alternatif penerapan model yang tepat guna menghadapi generasi Z saat ini. Teori-teori yang digunakan dalam penelitian ini diantaranya: (1) teori belajar, (2) teori pendidikan, (3) teori generasi, (4) teori pembelajaran holistik, dan (5) karya seni pertunjukan. Penelitian ini menggunakan metode penelitian Project Based Research berdasarkan paradigma kualitatif dengan pendekatan multidisiplin. Adapun rancangan penelitian yang dilakukan ditempuh melalui diagnosis masalah, prescribe, implementasi, dan evaluasi. Project Based Learning Model Merupakan pembelajaran berbasis pada proyek dan pengalaman dengan mengembangkan minat dan potensi peserta didik. Hal ini ditujukan dengan adanya konsep pembelajaran seni terpadu yang diterapkan melalui karya seni pertunjukan.-----Individuals in the learning process have different ways to develop the various intelligences that exist in him. Basically, each learner has the potential and interest to be developed in his education according to the competence. The purpose of this paper is to describe how to learn Learning Group of Learners, to design the design of project based learning model through the works of performing arts, to implement the design, and to evaluate the whole process and the result of art activities in the form of creation and appreciation. This research can be a topic to be raised in scientific research. Where, the role of teachers is not merely to implement the curriculum alone but able to interpret the words in the curriculum that is normative. In other words, the role of the teacher here must be a creative and interpretive actor. The application of learning models in the group of learning adventurers to be an alternative application of appropriate models to face the current Z generation. Theories used in this research include: (1) learning theory, (2) educational theory, (3) generation theory, (4) holistic learning theory, and (5) works of performing arts. This research uses Research Based Research method based on qualitative paradigm with multidisciplinary approach. The research design is done through the diagnosis of problems, prescribe, implementation, and evaluation. Project Based Learning Model Merupakan pembelajaran berbasis pada proyek dan pengalaman dengan mengembangkan minat dan potensi peserta didik. Hal ini ditujukan dengan adanya konsep pembelajaran seni terpadu yang diterapkan melalui karya seni pertunjuka

Vision and Foraging in Cormorants: More like Herons than Hawks?

Background Great cormorants (Phalacrocorax carbo L.) show the highest known foraging yield for a marine predator and they are often perceived to be in conflict with human economic interests. They are generally regarded as visually-guided, pursuit-dive foragers, so it would be expected that cormorants have excellent vision much like aerial predators, such as hawks which detect and pursue prey from a distance. Indeed cormorant eyes appear to show some specific adaptations to the amphibious life style. They are reported to have a highly pliable lens and powerful intraocular muscles which are thought to accommodate for the loss of corneal refractive power that accompanies immersion and ensures a well focussed image on the retina. However, nothing is known of the visual performance of these birds and how this might influence their prey capture technique. Methodology/Principal Findings We measured the aquatic visual acuity of great cormorants under a range of viewing conditions (illuminance, target contrast, viewing distance) and found it to be unexpectedly poor. Cormorant visual acuity under a range of viewing conditions is in fact comparable to unaided humans under water, and very inferior to that of aerial predators. We present a prey detectability model based upon the known acuity of cormorants at different illuminances, target contrasts and viewing distances. This shows that cormorants are able to detect individual prey only at close range (less than 1 m). Conclusions/Significance We conclude that cormorants are not the aquatic equivalent of hawks. Their efficient hunting involves the use of specialised foraging techniques which employ brief short-distance pursuit and/or rapid neck extension to capture prey that is visually detected or flushed only at short range. This technique appears to be driven proximately by the cormorant's limited visual capacities, and is analogous to the foraging techniques employed by herons

Estimating the number needed to treat from continuous outcomes in randomised controlled trials: methodological challenges and worked example using data from the UK Back Pain Exercise and Manipulation (BEAM) trial

Background Reporting numbers needed to treat (NNT) improves interpretability of trial results. It is unusual that continuous outcomes are converted to numbers of individual responders to treatment (i.e., those who reach a particular threshold of change); and deteriorations prevented are only rarely considered. We consider how numbers needed to treat can be derived from continuous outcomes; illustrated with a worked example showing the methods and challenges. Methods We used data from the UK BEAM trial (n = 1, 334) of physical treatments for back pain; originally reported as showing, at best, small to moderate benefits. Participants were randomised to receive 'best care' in general practice, the comparator treatment, or one of three manual and/or exercise treatments: 'best care' plus manipulation, exercise, or manipulation followed by exercise. We used established consensus thresholds for improvement in Roland-Morris disability questionnaire scores at three and twelve months to derive NNTs for improvements and for benefits (improvements gained+deteriorations prevented). Results At three months, NNT estimates ranged from 5.1 (95% CI 3.4 to 10.7) to 9.0 (5.0 to 45.5) for exercise, 5.0 (3.4 to 9.8) to 5.4 (3.8 to 9.9) for manipulation, and 3.3 (2.5 to 4.9) to 4.8 (3.5 to 7.8) for manipulation followed by exercise. Corresponding between-group mean differences in the Roland-Morris disability questionnaire were 1.6 (0.8 to 2.3), 1.4 (0.6 to 2.1), and 1.9 (1.2 to 2.6) points. Conclusion In contrast to small mean differences originally reported, NNTs were small and could be attractive to clinicians, patients, and purchasers. NNTs can aid the interpretation of results of trials using continuous outcomes. Where possible, these should be reported alongside mean differences. Challenges remain in calculating NNTs for some continuous outcomes

Conscious thought beats deliberation without attention in diagnostic decision-making: at least when you are an expert

Contrary to what common sense makes us believe, deliberation without attention has recently been suggested to produce better decisions in complex situations than deliberation with attention. Based on differences between cognitive processes of experts and novices, we hypothesized that experts make in fact better decisions after consciously thinking about complex problems whereas novices may benefit from deliberation-without-attention. These hypotheses were confirmed in a study among doctors and medical students. They diagnosed complex and routine problems under three conditions, an immediate-decision condition and two delayed conditions: conscious thought and deliberation-without-attention. Doctors did better with conscious deliberation when problems were complex, whereas reasoning mode did not matter in simple problems. In contrast, deliberation-without-attention improved novices’ decisions, but only in simple problems. Experts benefit from consciously thinking about complex problems; for novices thinking does not help in those cases

The new COSMIN guidelines confront traditional concepts of responsiveness

The recently published "COSMIN" guidelines aim to rate properties of outcome instruments and state two issues with regard to responsiveness which is the instrument's ability to detect change over time. These issues are comparison of score changes with change of an external criterion using correlations and the judgement of traditional methods as inappropriate. The latter are the "transition" concept, a global rating of change, and parametric measures of responsiveness, for example, effect sizes. It can be shown that the methodology proposed by the guidelines has important weaknesses and that denunciation of traditional methods is not appropriate. Some claims of the guidelines about responsiveness do not match the demands of clinical reality and confront findings of numerous epidemiological studies

Estimation of minimally important differences in EQ-5D utility and VAS scores in cancer

<p>Abstract</p> <p>Background</p> <p>Understanding what constitutes an important difference on a HRQL measure is critical to its interpretation. The aim of this study was to provide a range of estimates of minimally important differences (MIDs) in EQ-5D scores in cancer and to determine if estimates are comparable in lung cancer.</p> <p>Methods</p> <p>A retrospective analysis was conducted on cross-sectional data collected from 534 cancer patients, 50 of whom were lung cancer patients. A range of minimally important differences (MIDs) in EQ-5D index-based utility (UK and US) scores and VAS scores were estimated using both anchor-based and distribution-based (1/2 standard deviation and standard error of the measure) approaches. Groups were anchored using Eastern Cooperative Oncology Group performance status (PS) ratings and FACT-G total score-based quintiles.</p> <p>Results</p> <p>For UK-utility scores, MID estimates based on PS ranged from 0.10 to 0.12 both for all cancers and for lung cancer subgroup. Using FACT-G quintiles, MIDs were 0.09 to 0.10 for all cancers, and 0.07 to 0.08 for lung cancer. For US-utility scores, MIDs ranged from 0.07 to 0.09 grouped by PS for all cancers and for lung cancer; when based on FACT-G quintiles, MIDs were 0.06 to 0.07 in all cancers and 0.05 to 0.06 in lung cancer. MIDs for VAS scores were similar for lung and all cancers, ranging from 8 to 12 (PS) and 7 to 10 (FACT-G quintiles).</p> <p>Discussion</p> <p>Important differences in EQ-5D utility and VAS scores were similar for all cancers and lung cancer, with the lower end of the range of estimates closer to the MID, i.e. 0.08 for UK-index scores, 0.06 for US-index scores, and 0.07 for VAS scores.</p

Surgical management of life threatening events caused by intermittent aortic insufficiency in a native valve: case report

We describe a case of a patient admitted with apparent life threatening events characterized by hypotension and bradycardia. The patient was ultimately found to have intermittent severe aortic insufficiency. Upon surgical exploration, abnormalities were discovered in the aortic valve, which had a small left coronary cusp with absence of the nodulus of Arantius. Following surgical repair of the valve, aimed at preventing the small cusp from becoming stuck in the open position, the patient has remained episode free for over one year