74 resultados para technical trading rules
Resumo:
OBJECTIVES: To investigate the frequency of interim analyses, stopping rules, and data safety and monitoring boards (DSMBs) in protocols of randomized controlled trials (RCTs); to examine these features across different reasons for trial discontinuation; and to identify discrepancies in reporting between protocols and publications. STUDY DESIGN AND SETTING: We used data from a cohort of RCT protocols approved between 2000 and 2003 by six research ethics committees in Switzerland, Germany, and Canada. RESULTS: Of 894 RCT protocols, 289 prespecified interim analyses (32.3%), 153 stopping rules (17.1%), and 257 DSMBs (28.7%). Overall, 249 of 894 RCTs (27.9%) were prematurely discontinued; mostly due to reasons such as poor recruitment, administrative reasons, or unexpected harm. Forty-six of 249 RCTs (18.4%) were discontinued due to early benefit or futility; of those, 37 (80.4%) were stopped outside a formal interim analysis or stopping rule. Of 515 published RCTs, there were discrepancies between protocols and publications for interim analyses (21.1%), stopping rules (14.4%), and DSMBs (19.6%). CONCLUSION: Two-thirds of RCT protocols did not consider interim analyses, stopping rules, or DSMBs. Most RCTs discontinued for early benefit or futility were stopped without a prespecified mechanism. When assessing trial manuscripts, journals should require access to the protocol.
Resumo:
In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been used successfully in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits; to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles.
Resumo:
In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been successfully used in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits, to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles.
Resumo:
Neurophysiology is an essential tool for clinicians dealing with patients in the intensive care unit. Because of consciousness disorders, clinical examination is frequently limited. In this setting, neurophysiological examination provides valuable information about seizure detection, treatment guidance, and neurological outcome. However, to acquire reliable signals, some technical precautions need to be known. EEG is prone to artifacts, and the intensive care unit environment is rich in artifact sources (electrical devices including mechanical ventilation, dialysis, and sedative medications, and frequent noise, etc.). This review will discuss and summarize the current technical guidelines for EEG acquisition and also some practical pitfalls specific for the intensive care unit.
Resumo:
This article examines how Samuelson defined his own role as an economist as a technical expert, who walked what he called the "middle of the road" to-seemingly-stay out of the realm of politics. As point of entry I discuss the highly tempting offers made by Theodore M. Schultz in the 1940s to come over to Chicago, which Schultz persistently repeated over three years and despite strong Chicago faculty resistance. A contrast between Schultz's own experiences as an economic expert at Iowa State, Samuelson's work as an external consultant for the National Resources Planning Board during the Second World War, and the firm support of the MIT administration for Samuelson's research serves to pinpoint the meaning of being technical for Samuelson, and the relation of the technical economic expert to the realm of politics.
Resumo:
Communication is an essential element of good medical practice also in pathology. In contrast to technical or diagnostic skills, communication skills are not easy to define, teach, or assess. Rules almost do not exist. In this paper, which has a rather personal character and cannot be taken as a set of guidelines, important aspects of communication in pathology are explored. This includes what should be communicated to the pathologist on the pathology request form, communication between pathologists during internal (interpathologist) consultation, communication around frozen section diagnoses, modalities of communication of a final diagnosis, with whom and how critical and unexpected findings should be communicated, (in-)adequate routes of communication for pathology diagnoses, who will (or might) receive pathology reports, and what should be communicated and how in case of an error or a technical problem. An earlier more formal description of what the responsibilities are of a pathologist as communicator and as collaborator in a medical team is added in separate tables. The intention of the paper is to stimulate reflection and discussion rather than to formulate strict rules.
Resumo:
Once a country allergic to any type of preferential treatment or quota measure for women, France has become a country that applies gender quotas to regulate women's presence and representation in politics, the business sector, public bodies, public administration, and even some civil society organizations. While research has concentrated on the adoption of electoral gender quotas in many countries and their international diffusion, few studies focus on explaining the successful diffusion of gender quotas from politics to other domains in the same country. This paper proposes to fill this gap by studying the particularly puzzling case of a country that at one point strongly opposed the adoption of gender quotas in politics, but, in less than a decade, transformed into one of the few countries applying gender quotas across several policy domains. This paper argues that the legal entrenchment of the parity principle, the institutionalization of parity in several successive women's policy agencies, and key players in these newly created agencies are mainly responsible for this unexpected development. The diffusion of gender quotas in France thus offers an illuminating example of under which conditions women's policy agencies can act autonomously to diffuse and impose a new tool for gender equality
Resumo:
Early warning systems (EWSs) rely on the capacity to forecast a dangerous event with a certain amount of advance by defining warning criteria on which the safety of the population will depend. Monitoring of landslides is facilitated by new technologies, decreasing prices and easier data processing. At the same time, predicting the onset of a rapid failure or the sudden transition from slow to rapid failure and subsequent collapse, and its consequences is challenging for scientists that must deal with uncertainties and have limited tools to do so. Furthermore, EWS and warning criteria are becoming more and more a subject of concern between technical experts, researchers, stakeholders and decision makers responsible for the activation, enforcement and approval of civil protection actions. EWSs imply also a sharing of responsibilities which is often averted by technical staff, managers of technical offices and governing institutions. We organized the First International Workshop on Warning Criteria for Active Slides (IWWCAS) to promote sharing and networking among members from specialized institutions and relevant experts of EWS. In this paper, we summarize the event to stimulate discussion and collaboration between organizations dealing with the complex task of managing hazard and risk related to active slides.