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  • Restricted English
    Authors: 
    Mark S. Ackerman; Marlene Huysman; John M. Carroll; Barry Wellman; Giorgio DeMichelis; Volker Wulf;
    Country: Netherlands

    Communities are social entities whose actors share common needs, interests, or practices: they constitute the basic units of social experience. With regard to communities, social capital captures the structural, relational and cognitive aspects of the relationships among their members. Social capital is defined as a set of properties of a social entity (e.g. norms, level of trust, and intensive social networking) which enables joint activities and cooperation for mutual benefit. It can be understood as the glue which holds communities together. On this panel we will discuss whether and how information technology can strengthen communities by fostering social capital.

  • Restricted
    Authors: 
    Alexander V. Louie; Suresh Senan; Max Dahele; Ben J. Slotman; Wilko F.A.R. Verbakel;
    Country: Netherlands

    Purpose Use of stereotactic ablative radiation therapy (SABR) for subcentimeter lung tumors is controversial. We report our outcomes for tumors with diameter ≤1 cm and their visibility on cone beam computed tomography (CBCT) scans and retrospectively evaluate the planned dose using a deterministic dose calculation algorithm (Acuros XB [AXB]). Methods and Materials We identified subcentimeter tumors from our institutional SABR database. Tumor size was remeasured on an artifact-free phase of the planning 4-dimensional (4D)-CT. Clinical plan doses were generated using either a pencil beam convolution or an anisotropic analytic algorithm (AAA). All AAA plans were recalculated using AXB, and differences among D95 and mean dose for internal target volume (ITV) and planning target volume (PTV) on the average intensity CT dataset, as well as for gross tumor volume (GTV) on the end respiratory phases were reported. For all AAA patients, CBCT scans acquired during each treatment fraction were evaluated for target visibility. Progression-free and overall survival rates were calculated using the Kaplan-Meier method. Results Thirty-five patients with 37 subcentimeter tumors were eligible for analysis. For the 22 AAA plans recalculated using AXB, Mean D95 ± SD values were 2.2 ± 4.4% (ITV) and 2.5 ± 4.8% (PTV) lower using AXB; whereas mean doses were 2.9 ± 4.9% (ITV) and 3.7 ± 5.1% (PTV) lower. Calculated AXB doses were significantly lower in one patient (difference in mean ITV and PTV doses, as well as in mean ITV and PTV D95 ranged from 22%-24%). However, the end respiratory phase GTV received at least 95% of the prescription dose. Review of 92 CBCT scans from all AAA patients revealed that the tumor was visualized in 82 images, and its position could be inferred in other images. The 2-year local progression-free survival was 100%. Conclusions Patients with subcentimeter lung tumors are good candidates for SABR, given the dosimetry, ability to localize tumors with image guidance, and excellent local control.

  • Restricted
    Authors: 
    George Rodrigues; Suresh Senan; Cary Oberije; Kayoko Tsujino; T. Wiersma; Marta Moreno-Jiménez; Tae Hyun Kim; Lawrence B. Marks; Ramesh Rengan; L. De Petris; +6 more
    Country: Netherlands

    Purpose The clinical benefits and risks of dose escalation (DE) for stage III non–small-cell lung cancer (NSCLC) remain uncertain despite the results from Radiation Therapy Oncology Group (RTOG) protocol 0617. There is significant heterogeneity of practice, with many clinicians prescribing intermediate dose levels between the 0617 study arms of 60 and 74 Gy. This study investigated whether this strategy is associated with any survival benefits/risks by analyzing a large multi-institutional database. Methods and Materials An individual patient database of stage III NSCLC patients treated with radical intent concurrent chemoradiation therapy was created (13 institutions, n=1274 patients). Patients were divided into 2 groups based on tumor Biological Effective Dose at 10 Gy (BED 10): those receiving standard dose (SD; n=552), consisting of 72Gy ≤ BED 10 ≤ 76.8 Gy (eg 60-64 Gy/30-32 fractions [fr]), and those receiving intermediate dose (ID; n=497), consisting of 76.8Gy 64 Gy/32 fr and Results Matched groups were found to be balanced except for N stage (more N3 disease in SD), median treatment year (SD in 2003; ID in 2007), platinum and taxane chemotherapy (SD in 28%; ID in 39%), and median follow-up (SD were 89 months; ID were 40 months). Median dose fractionation was 60 Gy/30 fr in SD (BED 10 IQR: 72.0-75.5 Gy) and 66 Gy/33 fr (BED 10 IQR: 78.6-79.2 Gy) in ID. Survival curves for SD and ID matched cohorts were statistically similar ( P =.27); however, a nonstatistically significant trend toward better survival for ID was observed after 15 months (median survival SD: 19.3 months; ID: 21.0 months). There was an increase in grades III to V lung toxicity associated with ID (13.0% vs 4.9%, respectively). Conclusions No significant overall survival benefits were found with intermediate DE; however, more grade III or greater lung toxicity was observed. The separation of survival curves after 15 months of follow-up suggests that a small overall survival improvement associated with intermediate DE cannot be excluded.

  • Publication . Other literature type . Article . 2019
    Restricted English
    Authors: 
    Jessica Chan; Jeppe Friborg; Mikhail Chernov; Mikhail Cherkashin; Cai Grau; Michael Brundage; Ben J. Slotman;
    Country: Netherlands

    Summary Cancer is a substantial health burden for Inuit populations, an Indigenous peoples who primarily inhabit the circumpolar regions of Alaska, Canada, Greenland, and Russia. Access to radiotherapy is lacking or absent in many of these regions, despite it being an essential component of cancer treatment. This Review presents an overview of factors influencing radiotherapy delivery in each of the four circumpolar Inuit regions, which include population and geography, health-systems infrastructure, and cancer epidemiology. This Review also provides insight into the complex patient pathways needed to access radiotherapy, and on radiotherapy use. The unique challenges in delivering radiotherapy to circumpolar Inuit populations are discussed, which, notably, include geographical and cultural barriers. Recommendations include models of care that have successfully addressed these barriers, and highlight the need for increased collaboration between circumpolar referral centres in Alaska, Canada, Greenland, and Russia to ultimately allow for better delivery of cancer treatment.

  • Publication . Part of book or chapter of book . Other literature type . 2019
    Restricted English
    Authors: 
    Johnston, Bradley C.; Patrick, Donald L.; Devji, Tahira; Maxwell, Lara J.; Bingham, Clifton O.; Beaton, Dorcas E.; Boers, Maarten; Briel, Matthias; Busse, Jason W.; Carrasco-Labra, Alonso; +19 more
    Publisher: Wiley
    Country: Netherlands

    Authors of systematic reviews that include patient-reported outcomes (PROs) should have a good understanding of how patient-reported outcome measures (PROMs) are developed, including the constructs they are intended to measure, their reliability, validity and responsiveness. This chapter describes the category of outcomes known as PROs and their importance for healthcare decision making, and illustrates the key issues related to reliability, validity and responsiveness that systematic review authors should consider when including PROs. It also addresses the structure and content of PROs and provides guidance for combining information from different PROs. The chapter outlines a step-by-step approach to addressing each of these elements in the systematic review process. The focus is on the use of PROs in randomized trials, and what is crucial in this context when selecting PROs to include in a meta-analysis. The chapter describes PROMs in more detail and discusses some issues to consider when deciding which PROMs to address in a review.

  • Publication . Conference object . Article . 2008
    Restricted English
    Authors: 
    Thomas Zimmermann; Rahul Premraj; Nicolas Bettenburg; Sascha Just; Adrian Schroter; Cathrin Weiss;
    Country: Netherlands

    In software development, bug reports provide crucial information to developers. However, these reports widely differ in their quality. We conducted a survey among developers and users of APACHE, ECLIPSE, and MOZILLA to find out what makes a good bug report. The analysis of the 466 responses revealed an information mismatch between what developers need and what users supply. Most developers consider steps to reproduce, stack traces, and test cases as helpful, which are, at the same time, most difficult to provide for users. Such insight is helpful for designing new bug tracking tools that guide users at collecting and providing more helpful information. Our CUEZILLA prototype is such a tool and measures the quality of new bug reports; it also recommends which elements should be added to improve the quality. We trained CUEZILLA on a sample of 289 bug reports, rated by developers as part of the survey. The participants of our survey also provided 175 comments on hurdles in reporting and resolving bugs. Based on these comments, we discuss several recommendations for better bug tracking systems, which should focus on engaging bug reporters, better tool support, and improved handling of bug duplicates. © 2010 IEEE.

  • Restricted English
    Authors: 
    Caroline F. Finch; Roald Bahr; Jonathan A. Drezner; Jiri Dvorak; Lars Engebretsen; Timothy E. Hewett; Astrid Junge; Karim M. Khan; Domhnall MacAuley; Gordon O. Matheson; +2 more
    Country: Netherlands

    A decade ago, Blair1 pondered the future of physical activity research, much of which has since come to pass. More recently, a BJSM Blog2 invited readers to consider how their future research would look. Given the increased international focus on reducing injury/illness in athletes, it is timely to consider what research needs to be undertaken and acted on to achieve feasible reductions over the next 10 years. ‘Future Studies’3 or ‘Thought Leadership’ happens when a defined group of experts calls attention to what they think will be important for their field in the future. This is common in social science disciplines (eg, finance) and in scientific areas with major implications for policy development (eg, in climate control/environmental science). It has been less commonly applied in medicine, though it has underpinned discussion in areas like cancer research4 and academic medicine.5 Thought leadership involves big picture thinking and can lead to new ideas for major developments over time. There is evidence that such exercises can significantly shape research agenda and priority setting. This novel approach was applied to Sports and Exercise Medicine through asking a select group of international experts to contribute their priority research directions for the next 10 years. This is intended as a starting point only, to stimulate discussion with, and elicit responses from, the broader community interested in the prevention of injury and illness in athletes. International experts were invited to participate if they had delivered ≥1 keynote addresses at the International Olympic Committee (IOC) World Conferences of Prevention of Injury and Illness in Sport in 2011, 2014 or their precursor conferences organised by the Oslo Sports Trauma Research Centre in 2005 and 2008. Of 21 keynote speakers, 12 contributed their views to this paper. The experts covered a range of disciplines, including clinical sports …

  • Restricted
    Authors: 
    Ian Shrier; Russell Steele; Evert Verhagen; Robert D. Herbert; Corinne A. Riddell; Jay S. Kaufman;
    Publisher: SAGE Publications
    Country: Netherlands

    Background Most methodologists recommend intention-to-treat (ITT) analysis in order to minimize bias. Although ITT analysis provides an unbiased estimate for the effect of treatment assignment on the outcome, the estimate is biased for the actual effect of receiving treatment (active treatment) compared to some comparison group (control). Other common analyses include measuring effects in (1) participants who follow their assigned treatment (Per Protocol), (2) participants according to treatment received (As Treated), and (3) those who would comply with recommended treatment (Complier Average Causal Effect (CACE) as estimated by Principal Stratification or Instrumental Variable Analyses). As each of these analyses compares different study subpopulations, they address different research questions. Purpose For each type of analysis, we review and explain (1) the terminology being used, (2) the main underlying concepts, (3) the questions that are answered and whether the method provides valid causal estimates, and (4) the situations when the analysis should be conducted. Methods We first review the major concepts in relation to four nuances of the clinical question, ‘Does treatment improve health?’ After reviewing these concepts, we compare the results of the different analyses using data from two published randomized controlled trials (RCTs). Each analysis has particular underlying assumptions and all require dichotomizing adherence into Yes or No. We apply sensitivity analyses so that intermediate adherence is considered (1) as adherence and (2) as non-adherence. Results The ITT approach provides an unbiased estimate for how active treatment will improve (1) health in the population if a policy or program is enacted or (2) health of patients if a clinician changes treatment practice. The CACE approach generally provides an unbiased estimate of the effect of active treatment on health of patients who would follow the clinician’s advice to take active treatment. Unfortunately, there is no current analysis for clinicians and patients who want to know whether active treatment will improve the patient’s health if taken, which is different from the effect in patients who would follow the clinician’s advice to take active treatment. Sensitivity analysis for the CACE using two published data sets suggests that the underlying assumptions appeared to be violated. Limitations There are several methods within each analytical approach we describe. Our analyses are based on a subset of these approaches. Conclusions Although adherence-based analyses may provide meaningful information, the analytical method should match the clinical question, and investigators should clearly outline why they believe assumptions hold and should provide empirical tests of the assumptions where possible.

  • Restricted English
    Authors: 
    Triin Reitalu; Heikki Seppä; Shinya Sugita; Mihkel Kangur; Tiiu Koff; Eve Avel; Kersti Kihno; J. Vassiljev; Hans Renssen; Dan Hammarlund; +4 more
    Country: Netherlands

    Aim To assess statistically the relative importance of climate and human impact on forest composition in the late Holocene. Location Estonia, boreonemoral Europe. Methods Data on forest composition (10 most abundant tree and shrub taxa) for the late Holocene (5100-50 calibrated years before 1950) were derived from 18 pollen records and then transformed into land-cover estimates using the REVEALS vegetation reconstruction model. Human impact was quantified with palaeoecological estimates of openness, frequencies of hemerophilous pollen types (taxa growing in habitats influenced by human activities) and microscopic charcoal particles. Climate data generated with the ECBilt-CLIO-VECODE climate model provided summer and winter temperature data. The modelled data were supported by sedimentary stable oxygen isotope (O-18) records. Redundancy analysis (RDA), variation partitioning and linear mixed effects (LME) models were applied for statistical analyses. Results Both climate and human impact were statistically significant predictors of forest compositional change during the late Holocene. While climate exerted a dominant influence on forest composition in the beginning of the study period, human impact was the strongest driver of forest composition change in the middle of the study period, c.4000-2000years ago, when permanent agriculture became established and expanded. The late Holocene cooling negatively affected populations of nemoral deciduous taxa (Tilia, Corylus, Ulmus, Quercus, Alnus and Fraxinus), allowing boreal taxa (Betula, Salix, Picea and Pinus) to succeed. Whereas human impact has favoured populations of early-successional taxa that colonize abandoned agricultural fields (Betula, Salix, Alnus) or that can grow on less fertile soils (Pinus), it has limited taxa such as Picea that tend to grow on more mesic and fertile soils. Main conclusions Combining palaeoecological and palaeoclimatological data from multiple sources facilitates quantitative characterization of factors driving forest composition dynamics on millennial time-scales. Our results suggest that in addition to the climatic influence on forest composition, the relative abundance of individual forest taxa has been significantly influenced by human impact over the last four millennia.

  • Publication . Article . 2016
    Restricted English
    Authors: 
    Christian Ehm; Roberta Cipullo; Peter H. M. Budzelaar; Vincenzo Busico;
    Country: Italy

    Quenched-flow data for propene polymerization with rac-Me2Si(2-Me-4-Ph-1-indenyl)(2)ZrCl2/MAO support a picture where removal of MAO qualitatively changes the kinetic profile from a mainly enthalpic to a mainly entropic barrier. DFT studies suggest that a not previously recognized singly-bridged end-on coordination mode of Me6Al2 to catalytically active centers may be kinetically relevant as a resting state. In contrast, the more traditional doubly-bridged complex of Me3Al is proposed to be more relevant to chain transfer to cocatalyst.

search
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
752 Research products, page 1 of 76
  • Restricted English
    Authors: 
    Mark S. Ackerman; Marlene Huysman; John M. Carroll; Barry Wellman; Giorgio DeMichelis; Volker Wulf;
    Country: Netherlands

    Communities are social entities whose actors share common needs, interests, or practices: they constitute the basic units of social experience. With regard to communities, social capital captures the structural, relational and cognitive aspects of the relationships among their members. Social capital is defined as a set of properties of a social entity (e.g. norms, level of trust, and intensive social networking) which enables joint activities and cooperation for mutual benefit. It can be understood as the glue which holds communities together. On this panel we will discuss whether and how information technology can strengthen communities by fostering social capital.

  • Restricted
    Authors: 
    Alexander V. Louie; Suresh Senan; Max Dahele; Ben J. Slotman; Wilko F.A.R. Verbakel;
    Country: Netherlands

    Purpose Use of stereotactic ablative radiation therapy (SABR) for subcentimeter lung tumors is controversial. We report our outcomes for tumors with diameter ≤1 cm and their visibility on cone beam computed tomography (CBCT) scans and retrospectively evaluate the planned dose using a deterministic dose calculation algorithm (Acuros XB [AXB]). Methods and Materials We identified subcentimeter tumors from our institutional SABR database. Tumor size was remeasured on an artifact-free phase of the planning 4-dimensional (4D)-CT. Clinical plan doses were generated using either a pencil beam convolution or an anisotropic analytic algorithm (AAA). All AAA plans were recalculated using AXB, and differences among D95 and mean dose for internal target volume (ITV) and planning target volume (PTV) on the average intensity CT dataset, as well as for gross tumor volume (GTV) on the end respiratory phases were reported. For all AAA patients, CBCT scans acquired during each treatment fraction were evaluated for target visibility. Progression-free and overall survival rates were calculated using the Kaplan-Meier method. Results Thirty-five patients with 37 subcentimeter tumors were eligible for analysis. For the 22 AAA plans recalculated using AXB, Mean D95 ± SD values were 2.2 ± 4.4% (ITV) and 2.5 ± 4.8% (PTV) lower using AXB; whereas mean doses were 2.9 ± 4.9% (ITV) and 3.7 ± 5.1% (PTV) lower. Calculated AXB doses were significantly lower in one patient (difference in mean ITV and PTV doses, as well as in mean ITV and PTV D95 ranged from 22%-24%). However, the end respiratory phase GTV received at least 95% of the prescription dose. Review of 92 CBCT scans from all AAA patients revealed that the tumor was visualized in 82 images, and its position could be inferred in other images. The 2-year local progression-free survival was 100%. Conclusions Patients with subcentimeter lung tumors are good candidates for SABR, given the dosimetry, ability to localize tumors with image guidance, and excellent local control.

  • Restricted
    Authors: 
    George Rodrigues; Suresh Senan; Cary Oberije; Kayoko Tsujino; T. Wiersma; Marta Moreno-Jiménez; Tae Hyun Kim; Lawrence B. Marks; Ramesh Rengan; L. De Petris; +6 more
    Country: Netherlands

    Purpose The clinical benefits and risks of dose escalation (DE) for stage III non–small-cell lung cancer (NSCLC) remain uncertain despite the results from Radiation Therapy Oncology Group (RTOG) protocol 0617. There is significant heterogeneity of practice, with many clinicians prescribing intermediate dose levels between the 0617 study arms of 60 and 74 Gy. This study investigated whether this strategy is associated with any survival benefits/risks by analyzing a large multi-institutional database. Methods and Materials An individual patient database of stage III NSCLC patients treated with radical intent concurrent chemoradiation therapy was created (13 institutions, n=1274 patients). Patients were divided into 2 groups based on tumor Biological Effective Dose at 10 Gy (BED 10): those receiving standard dose (SD; n=552), consisting of 72Gy ≤ BED 10 ≤ 76.8 Gy (eg 60-64 Gy/30-32 fractions [fr]), and those receiving intermediate dose (ID; n=497), consisting of 76.8Gy 64 Gy/32 fr and Results Matched groups were found to be balanced except for N stage (more N3 disease in SD), median treatment year (SD in 2003; ID in 2007), platinum and taxane chemotherapy (SD in 28%; ID in 39%), and median follow-up (SD were 89 months; ID were 40 months). Median dose fractionation was 60 Gy/30 fr in SD (BED 10 IQR: 72.0-75.5 Gy) and 66 Gy/33 fr (BED 10 IQR: 78.6-79.2 Gy) in ID. Survival curves for SD and ID matched cohorts were statistically similar ( P =.27); however, a nonstatistically significant trend toward better survival for ID was observed after 15 months (median survival SD: 19.3 months; ID: 21.0 months). There was an increase in grades III to V lung toxicity associated with ID (13.0% vs 4.9%, respectively). Conclusions No significant overall survival benefits were found with intermediate DE; however, more grade III or greater lung toxicity was observed. The separation of survival curves after 15 months of follow-up suggests that a small overall survival improvement associated with intermediate DE cannot be excluded.

  • Publication . Other literature type . Article . 2019
    Restricted English
    Authors: 
    Jessica Chan; Jeppe Friborg; Mikhail Chernov; Mikhail Cherkashin; Cai Grau; Michael Brundage; Ben J. Slotman;
    Country: Netherlands

    Summary Cancer is a substantial health burden for Inuit populations, an Indigenous peoples who primarily inhabit the circumpolar regions of Alaska, Canada, Greenland, and Russia. Access to radiotherapy is lacking or absent in many of these regions, despite it being an essential component of cancer treatment. This Review presents an overview of factors influencing radiotherapy delivery in each of the four circumpolar Inuit regions, which include population and geography, health-systems infrastructure, and cancer epidemiology. This Review also provides insight into the complex patient pathways needed to access radiotherapy, and on radiotherapy use. The unique challenges in delivering radiotherapy to circumpolar Inuit populations are discussed, which, notably, include geographical and cultural barriers. Recommendations include models of care that have successfully addressed these barriers, and highlight the need for increased collaboration between circumpolar referral centres in Alaska, Canada, Greenland, and Russia to ultimately allow for better delivery of cancer treatment.

  • Publication . Part of book or chapter of book . Other literature type . 2019
    Restricted English
    Authors: 
    Johnston, Bradley C.; Patrick, Donald L.; Devji, Tahira; Maxwell, Lara J.; Bingham, Clifton O.; Beaton, Dorcas E.; Boers, Maarten; Briel, Matthias; Busse, Jason W.; Carrasco-Labra, Alonso; +19 more
    Publisher: Wiley
    Country: Netherlands

    Authors of systematic reviews that include patient-reported outcomes (PROs) should have a good understanding of how patient-reported outcome measures (PROMs) are developed, including the constructs they are intended to measure, their reliability, validity and responsiveness. This chapter describes the category of outcomes known as PROs and their importance for healthcare decision making, and illustrates the key issues related to reliability, validity and responsiveness that systematic review authors should consider when including PROs. It also addresses the structure and content of PROs and provides guidance for combining information from different PROs. The chapter outlines a step-by-step approach to addressing each of these elements in the systematic review process. The focus is on the use of PROs in randomized trials, and what is crucial in this context when selecting PROs to include in a meta-analysis. The chapter describes PROMs in more detail and discusses some issues to consider when deciding which PROMs to address in a review.

  • Publication . Conference object . Article . 2008
    Restricted English
    Authors: 
    Thomas Zimmermann; Rahul Premraj; Nicolas Bettenburg; Sascha Just; Adrian Schroter; Cathrin Weiss;
    Country: Netherlands

    In software development, bug reports provide crucial information to developers. However, these reports widely differ in their quality. We conducted a survey among developers and users of APACHE, ECLIPSE, and MOZILLA to find out what makes a good bug report. The analysis of the 466 responses revealed an information mismatch between what developers need and what users supply. Most developers consider steps to reproduce, stack traces, and test cases as helpful, which are, at the same time, most difficult to provide for users. Such insight is helpful for designing new bug tracking tools that guide users at collecting and providing more helpful information. Our CUEZILLA prototype is such a tool and measures the quality of new bug reports; it also recommends which elements should be added to improve the quality. We trained CUEZILLA on a sample of 289 bug reports, rated by developers as part of the survey. The participants of our survey also provided 175 comments on hurdles in reporting and resolving bugs. Based on these comments, we discuss several recommendations for better bug tracking systems, which should focus on engaging bug reporters, better tool support, and improved handling of bug duplicates. © 2010 IEEE.

  • Restricted English
    Authors: 
    Caroline F. Finch; Roald Bahr; Jonathan A. Drezner; Jiri Dvorak; Lars Engebretsen; Timothy E. Hewett; Astrid Junge; Karim M. Khan; Domhnall MacAuley; Gordon O. Matheson; +2 more
    Country: Netherlands

    A decade ago, Blair1 pondered the future of physical activity research, much of which has since come to pass. More recently, a BJSM Blog2 invited readers to consider how their future research would look. Given the increased international focus on reducing injury/illness in athletes, it is timely to consider what research needs to be undertaken and acted on to achieve feasible reductions over the next 10 years. ‘Future Studies’3 or ‘Thought Leadership’ happens when a defined group of experts calls attention to what they think will be important for their field in the future. This is common in social science disciplines (eg, finance) and in scientific areas with major implications for policy development (eg, in climate control/environmental science). It has been less commonly applied in medicine, though it has underpinned discussion in areas like cancer research4 and academic medicine.5 Thought leadership involves big picture thinking and can lead to new ideas for major developments over time. There is evidence that such exercises can significantly shape research agenda and priority setting. This novel approach was applied to Sports and Exercise Medicine through asking a select group of international experts to contribute their priority research directions for the next 10 years. This is intended as a starting point only, to stimulate discussion with, and elicit responses from, the broader community interested in the prevention of injury and illness in athletes. International experts were invited to participate if they had delivered ≥1 keynote addresses at the International Olympic Committee (IOC) World Conferences of Prevention of Injury and Illness in Sport in 2011, 2014 or their precursor conferences organised by the Oslo Sports Trauma Research Centre in 2005 and 2008. Of 21 keynote speakers, 12 contributed their views to this paper. The experts covered a range of disciplines, including clinical sports …

  • Restricted
    Authors: 
    Ian Shrier; Russell Steele; Evert Verhagen; Robert D. Herbert; Corinne A. Riddell; Jay S. Kaufman;
    Publisher: SAGE Publications
    Country: Netherlands

    Background Most methodologists recommend intention-to-treat (ITT) analysis in order to minimize bias. Although ITT analysis provides an unbiased estimate for the effect of treatment assignment on the outcome, the estimate is biased for the actual effect of receiving treatment (active treatment) compared to some comparison group (control). Other common analyses include measuring effects in (1) participants who follow their assigned treatment (Per Protocol), (2) participants according to treatment received (As Treated), and (3) those who would comply with recommended treatment (Complier Average Causal Effect (CACE) as estimated by Principal Stratification or Instrumental Variable Analyses). As each of these analyses compares different study subpopulations, they address different research questions. Purpose For each type of analysis, we review and explain (1) the terminology being used, (2) the main underlying concepts, (3) the questions that are answered and whether the method provides valid causal estimates, and (4) the situations when the analysis should be conducted. Methods We first review the major concepts in relation to four nuances of the clinical question, ‘Does treatment improve health?’ After reviewing these concepts, we compare the results of the different analyses using data from two published randomized controlled trials (RCTs). Each analysis has particular underlying assumptions and all require dichotomizing adherence into Yes or No. We apply sensitivity analyses so that intermediate adherence is considered (1) as adherence and (2) as non-adherence. Results The ITT approach provides an unbiased estimate for how active treatment will improve (1) health in the population if a policy or program is enacted or (2) health of patients if a clinician changes treatment practice. The CACE approach generally provides an unbiased estimate of the effect of active treatment on health of patients who would follow the clinician’s advice to take active treatment. Unfortunately, there is no current analysis for clinicians and patients who want to know whether active treatment will improve the patient’s health if taken, which is different from the effect in patients who would follow the clinician’s advice to take active treatment. Sensitivity analysis for the CACE using two published data sets suggests that the underlying assumptions appeared to be violated. Limitations There are several methods within each analytical approach we describe. Our analyses are based on a subset of these approaches. Conclusions Although adherence-based analyses may provide meaningful information, the analytical method should match the clinical question, and investigators should clearly outline why they believe assumptions hold and should provide empirical tests of the assumptions where possible.

  • Restricted English
    Authors: 
    Triin Reitalu; Heikki Seppä; Shinya Sugita; Mihkel Kangur; Tiiu Koff; Eve Avel; Kersti Kihno; J. Vassiljev; Hans Renssen; Dan Hammarlund; +4 more
    Country: Netherlands

    Aim To assess statistically the relative importance of climate and human impact on forest composition in the late Holocene. Location Estonia, boreonemoral Europe. Methods Data on forest composition (10 most abundant tree and shrub taxa) for the late Holocene (5100-50 calibrated years before 1950) were derived from 18 pollen records and then transformed into land-cover estimates using the REVEALS vegetation reconstruction model. Human impact was quantified with palaeoecological estimates of openness, frequencies of hemerophilous pollen types (taxa growing in habitats influenced by human activities) and microscopic charcoal particles. Climate data generated with the ECBilt-CLIO-VECODE climate model provided summer and winter temperature data. The modelled data were supported by sedimentary stable oxygen isotope (O-18) records. Redundancy analysis (RDA), variation partitioning and linear mixed effects (LME) models were applied for statistical analyses. Results Both climate and human impact were statistically significant predictors of forest compositional change during the late Holocene. While climate exerted a dominant influence on forest composition in the beginning of the study period, human impact was the strongest driver of forest composition change in the middle of the study period, c.4000-2000years ago, when permanent agriculture became established and expanded. The late Holocene cooling negatively affected populations of nemoral deciduous taxa (Tilia, Corylus, Ulmus, Quercus, Alnus and Fraxinus), allowing boreal taxa (Betula, Salix, Picea and Pinus) to succeed. Whereas human impact has favoured populations of early-successional taxa that colonize abandoned agricultural fields (Betula, Salix, Alnus) or that can grow on less fertile soils (Pinus), it has limited taxa such as Picea that tend to grow on more mesic and fertile soils. Main conclusions Combining palaeoecological and palaeoclimatological data from multiple sources facilitates quantitative characterization of factors driving forest composition dynamics on millennial time-scales. Our results suggest that in addition to the climatic influence on forest composition, the relative abundance of individual forest taxa has been significantly influenced by human impact over the last four millennia.

  • Publication . Article . 2016
    Restricted English
    Authors: 
    Christian Ehm; Roberta Cipullo; Peter H. M. Budzelaar; Vincenzo Busico;
    Country: Italy

    Quenched-flow data for propene polymerization with rac-Me2Si(2-Me-4-Ph-1-indenyl)(2)ZrCl2/MAO support a picture where removal of MAO qualitatively changes the kinetic profile from a mainly enthalpic to a mainly entropic barrier. DFT studies suggest that a not previously recognized singly-bridged end-on coordination mode of Me6Al2 to catalytically active centers may be kinetically relevant as a resting state. In contrast, the more traditional doubly-bridged complex of Me3Al is proposed to be more relevant to chain transfer to cocatalyst.