Isotope effects in switchable metal-hydride mirrors

Measurements of optical reflectance, transmittance, and electrical resistivity on the switchable mirror systems YHx and YDx show that the absorption of hydrogen induces the same variations as that of deuterium. In both cases there is a weak transparency window for the metallic dihydride (dideuteride) phase and a yellowish transparency in the insulating trihydride (trideuteride) phase. The slightly higher electrical resistivity of the deuterides is related to the lower energy of their optical phonons. The absence of significant isotope effects in the optical properties of YHx(YDx) is at variance with Peierls-like theoretical models. It is, however, compatible with strong electron correlation model

Uncertainty analysis using Bayesian Model Averaging: a case study of input variables to energy models and inference to associated uncertainties of energy scenarios

Background Energy models are used to illustrate, calculate and evaluate energy futures under given assumptions. The results of energy models are energy scenarios representing uncertain energy futures. Methods The discussed approach for uncertainty quantification and evaluation is based on Bayesian Model Averaging for input variables to quantitative energy models. If the premise is accepted that the energy model results cannot be less uncertain than the input to energy models, the proposed approach provides a lower bound of associated uncertainty. The evaluation of model-based energy scenario uncertainty in terms of input variable uncertainty departing from a probabilistic assessment is discussed. Results The result is an explicit uncertainty quantification for input variables of energy models based on well-established measure and probability theory. The quantification of uncertainty helps assessing the predictive potential of energy scenarios used and allows an evaluation of possible consequences as promoted by energy scenarios in a highly uncertain economic, environmental, political and social target system. Conclusions If societal decisions are vested in computed model results, it is meaningful to accompany these with an uncertainty assessment. Bayesian Model Averaging (BMA) for input variables of energy models could add to the currently limited tools for uncertainty assessment of model-based energy scenarios

Societal Innovation: between dream and reality lies complexity

Jan Rotmans (1961) is one of the founders of Integrated Assessment (IA), and has outstanding experience in IA modeling, scenario-building, uncertainty management and transition management. During the past twenty years he has led a diversity of innovative projects in the field of climate change, global change, sustainable development and transitions and system innovations. He is founder and director of the International Centre for Integrative Studies (ICIS) (1998) at Maastricht University. Since 2004 he is a full professor in Transitions and Transition Management at Erasmus University Rotterdam in the Netherlands, where he founded the DRIFT-institute: Dutch Research Institute For Transitions. He is vice-president of The Integrated Assessment Society (TIAS), and founder and director of the Dutch Knowledge Network on System Innovations and Transitions (KSI). Jan Rotmans is founder of two scientific journals, Environmental Modeling and Assessment and Integrated Assessment, and has published ten books and more than 150 peer-reviewed scientific articles in journals and books in the fields of environment, sustainability, governance, transitions and system innovations.There are no easy, off-the-shelf solutions for persistent societal problems, because these are caused by fundamental flaws in our societal systems. Such systemic errors demand radical changes in our thinking and actions, i.e. transitions and system innovations. Transitions require a long period (one to two generations), and take time, patience, money, confidence, but also courage, daring and perseverance to gain the upper hand over various types of resistance. Research into transitions is by definition multidisciplinary and interdisciplinary. For this we need knowledge and experience from systems analysis, social administration, history, innovation science, economics, business administration and technology. The nature of research into transitions is fundamental, explorative, creative and practical. A conceptual framework for research into transitions is presented that consists of four interlinked conceptual building blocks, which in turn provide an outline of a transition theory in its embryonic stages. These concepts are rooted in common notions from complexity theory, new forms of governance and social theory. Central here is the concept of transition management, for which a new management framework is developed. Transition management is an attempt to tackle persistent stubborn problems by steering them in a more sustainable direction, through a visionary, cyclical process of putting issues on the agenda, learning, orchestrating and experimenting. Not based on management and control but through clever, subtle changes and adjustments at several levels concurrently. Transition management is a very promising management concept that can initially be applied to a wide range of complex societal problems: from health care to energy provision, and from social security to mobility. Transition management can also be applied to complex processes of change in a business context.Voor hardnekkige maatschappelijke problemen bestaan geen pasklare oplossingen. Deze zijn het gevolg van weeffouten in onze maatschappelijke stelsels. Deze systeemfouten vergen radicale veranderingen in ons denken en handelen: transities en systeeminnovaties. Transities vergen een lange periode (1 à 2 generaties), en kosten tijd, geduld, geld, vertrouwen, maar ook moed, durf en doorzettingsvermogen om verschillende soorten weerstand te overwinnen. Onderzoek naar transities is per definitie multi-en interdisciplinair, waarbij kennis nodig is vanuit de systeemkunde, bestuurskunde, geschiedenis, innovatiewetenschappen, economie, bedrijfskunde en techniek. Transitieonderzoek is zowel fundamenteel, exploratief, ontwerpend en praktisch van aard. Een conceptueel kader voor transitieonderzoek wordt gepresenteerd, dat bestaat uit een viertal samenhangende conceptuele bouwstenen, die de contouren vormen van een transitietheorie in wording. Deze concepten zijn geworteld in gemeenschappelijke noties uit de complexiteitstheorie, nieuwe vormen van governance en de sociale theorie. Centraal hierin staat het concept van transitiemanagement, waarvoor een nieuw sturingsraamwerk is ontwikkeld. Transitiemanagement beoogt hardnekkige problemen bij te sturen in een meer duurzame richting, via een visionair, cyclisch proces van agenderen, leren, instrumenteren en experimenteren. Niet op basis van controle en beheersing, maar via slim, subtiel schakelen en bijsturen op meerdere niveaus. Transitiemanagement is een veelbelovend sturingsconcept wat in beginsel toepasbaar is op tal van complexe maatschappelijke problemen: van gezondheidszorg tot energievoorziening, en van sociale zekerheid tot mobiliteit. Ook in de bedrijfscontext kan transitiemanagement worden toegepast op complexe veranderingsprocessen

A risk score for iliofemoral patients with deep vein thrombosis

Objective: Deep vein thrombosis (DVT) is a common condition with a high risk of post-thrombotic morbidity, especially in patients with a proximal thrombus. Successful iliofemoral clot removal has been shown to decrease the severity of postthrombotic syndrome. It is assumed that earlier thrombus lysis is associated with a better outcome. Generally, the earlier IFDVT is confirmed, the earlier thrombus lysis could be performed. D-Dimer levels and Wells score are currently used to assess the preduplex probability for DVT; however, some studies indicate that the D-dimer value varies depending on the thrombus extent and localization. Using D-dimer and other risk factors might facilitate development of a model selecting those with an increased risk of IFDVT that might benefit from early referral for additional analysis and adjunctive iliofemoral thrombectomy.Methods: All consecutive adult patients from a retrospective cohort of STAR diagnostic center (primary care) in Rotterdam suspected of having DVT between September 2004 and August 2016 were assessed for this retrospective study. The diagnostic workup for DVT including Wells score and D-dimer were performed as well as complete duplex ultrasound examination. Patients with objective evidence of DVT were categorized according to thrombus localization using the Lower Extremity Thrombolysis classification. Logistic regression analysis was done for a model predicting IFDVT. The cutoff value of the model was determined using a receiver operating characteristic curve.Results: A total of 3381 patients were eligible for study recruitment, of whom 489 (14.5%) had confirmed DVT. We developed a multivariate model (sensitivity of 77% and specificity of 82%; area under the curve, 0.90; 0.86-0.93) based on D-dimer, Wells score, age, and anticoagulation use, which is able to distinguish IFDVT patients from all patients suspected of DVT.Conclusions: This multivariate model adequately distinguishes IFDVT among all suspected DVT patients. Practically, this model could give each patient a preduplex risk score, which could be used to prioritize suspected IFDVT patients for an immediate imaging test to confirm or exclude IFDVT. Further validation studies are needed to confirm potential of this prediction model for IFDVT

Comparison of translabial 3D ultrasound with MRI for measuring levator hiatus biometry at rest

OBJECTIVES: To compare translabial three-dimensional (3D) ultrasound with magnetic resonance imaging (MRI) for the measurement of levator hiatus biometry at rest in women with pelvic organ prolapse, and to determine the interobserver reliability between two independent observers for ultrasound and MRI measurements. METHODS: In a multicentre prospective cohort study, women planned for conventional anterior colporrhaphy underwent translabial 3D ultrasound and MRI prior to surgery. Intraclass Correlation Coefficients (ICC) were calculated to estimate the interobserver reliability between two independent observers and to calculate the agreement between ultrasound and MRI measurements. Bland-Altman plots were created to visualize the agreement between ultrasound and MRI measurements. RESULTS: One hundred thirty-nine women were included in 9 hospitals. The interobserver reliability between the assessments on ultrasound at rest, during Valsalva and during contraction and on MRI at rest by two independent observers was good. The agreement between ultrasound and MRI for the measurements of levator hiatus biometry at rest was moderate with an ICC of 0.52 (95% confidence interval (CI) 0.32-0.66) for levator hiatal area, an ICC of 0.44 (95% CI 0.21-0.60) for the anteroposterior diameter and an ICC of 0.44 (95% CI 0.22-0.60) for the transversal diameter. MRI measurements were statistically significantly larger than on translabial 3D ultrasound. CONCLUSIONS: The agreement between translabial 3D ultrasound and MRI for the measurement of the levator hiatus biometry at rest in women with pelvic organ prolapse was only moderate. The results of translabial 3D ultrasound and MRI should therefore not be interchangeably used in daily practice or in clinical research

Comparison of translabial three-dimensional ultrasound with magnetic resonance imaging for measurement of levator hiatal biometry at rest

Contains fulltext : 172187.pdf (publisher's version ) (Closed access)OBJECTIVES: To compare translabial three-dimensional (3D) ultrasound with magnetic resonance imaging (MRI) for the measurement of levator hiatal biometry at rest in women with pelvic organ prolapse, and to determine the interobserver reliability between two independent observers for ultrasound and MRI measurements. METHODS: Data were derived from a multicenter prospective cohort study in which women scheduled for conventional anterior colporrhaphy underwent translabial 3D ultrasound and MRI prior to surgery. Intraclass correlation coefficients (ICCs) were calculated to estimate interobserver reliability between two independent observers and determine the agreement between ultrasound and MRI measurements. Bland-Altman plots were created to assess the agreement between ultrasound and MRI measurements. RESULTS: Data from 139 women from nine hospitals were included in the study. The interobserver reliability of ultrasound assessment at rest, during Valsalva maneuver and during contraction and of MRI assessment at rest were moderate or good. The agreement between ultrasound and MRI for the measurement of levator hiatal biometry at rest was moderate, with ICCs of 0.52 (95%CI, 0.32-0.66) for levator hiatal area, 0.44 (95%CI, 0.21-0.60) for anteroposterior diameter and 0.44 (95%CI, 0.22-0.60) for transverse diameter. Levator hiatal biometry measurements were statistically significantly larger on MRI than on translabial 3D ultrasound. CONCLUSIONS: The agreement between translabial 3D ultrasound and MRI for measurement of the levator hiatus at rest in women with pelvic organ prolapse was only moderate. The results of translabial 3D ultrasound and MRI should therefore not be used interchangeably in daily practice or in clinical research. Copyright (c) 2015 ISUOG. Published by John Wiley & Sons Ltd

Comparison of translabial 3D ultrasound with MRI for measuring levator hiatus biometry at rest

OBJECTIVES: To compare translabial three-dimensional (3D) ultrasound with magnetic resonance imaging (MRI) for the measurement of levator hiatus biometry at rest in women with pelvic organ prolapse, and to determine the interobserver reliability between two independent observers for ultrasound and MRI measurements. METHODS: In a multicentre prospective cohort study, women planned for conventional anterior colporrhaphy underwent translabial 3D ultrasound and MRI prior to surgery. Intraclass Correlation Coefficients (ICC) were calculated to estimate the interobserver reliability between two independent observers and to calculate the agreement between ultrasound and MRI measurements. Bland-Altman plots were created to visualize the agreement between ultrasound and MRI measurements. RESULTS: One hundred thirty-nine women were included in 9 hospitals. The interobserver reliability between the assessments on ultrasound at rest, during Valsalva and during contraction and on MRI at rest by two independent observers was good. The agreement between ultrasound and MRI for the measurements of levator hiatus biometry at rest was moderate with an ICC of 0.52 (95% confidence interval (CI) 0.32-0.66) for levator hiatal area, an ICC of 0.44 (95% CI 0.21-0.60) for the anteroposterior diameter and an ICC of 0.44 (95% CI 0.22-0.60) for the transversal diameter. MRI measurements were statistically significantly larger than on translabial 3D ultrasound. CONCLUSIONS: The agreement between translabial 3D ultrasound and MRI for the measurement of the levator hiatus biometry at rest in women with pelvic organ prolapse was only moderate. The results of translabial 3D ultrasound and MRI should therefore not be interchangeably used in daily practice or in clinical research