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- Buck, Dietrich, 1990-
(författare)
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Mechanics of Cross-Laminated Timber
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. Wood is a sustainable, renewable material, and the increasing use of wood in construction contributes to its sustainability. Multi-layer wooden panels are one type of engineered wood product used in construction.There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. Assembly techniques considered in the earliest stages of this research work were laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. Cross-laminated timber (CLT) was found to offer some advantages over these other techniques. It is cost-effective, not patented, offers freedom of choice regarding the visibility of surfaces, provides the possibility of using different timber quality in the same panel at different points of its thickness, and is the most well-established assembly technique currently used in the industrial market.Building upon that foundational work, the operational capabilities of CLT were further evaluated by creating panels with different layer orientations. The mechanical properties of CLT panels constructed with layers angled in an alternative configuration produced on a modified industrial CLT production line were evaluated. Timber lamellae were adhesively bonded in a single-step press procedure to form CLT panels. Transverse layers were laid at a 45° angle instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle.Tests were carried out on 40 five-layered CLT panels, each with either a ±45° or a 90° configuration. Half of these panels were evaluated under bending: out-of-plane loading was applied in the principal orientation of the panels via four-point bending. The other twenty were evaluated under compression: an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. Quasi-static loading conditions were used for both in- and out-of-plane testing to determine the extent to which the load-bearing capacity of such panels could be enhanced under the current load case. Modified CLT showed higher stiffness, strength, and fifth-percentile characteristics, values that indicate the load-bearing capacity of these panels as a construction material. Failure modes under in- and out-of-plane loading for each panel type were also assessed.Data from out-of-plane loading were further analysed. A non-contact full-field measurement and analysis technique based on digital image correlation (DIC) was utilised for analysis at global and local scales. DIC evaluation of 100 CLT layers showed that a considerable part of the stiffness of conventional CLT is reduced by the shear resistance of its transverse layers. The presence of heterogeneous features, such as knots, has the desirable effect of reducing the propagation of shear fraction along the layers. These results call into question the current grading criteria in the CLT standard. It is suggested that the lower timber grading limit be adjusted for increased value-yield.The overall experimental results suggest the use of CLT panels with a ±45°-layered configuration for construction. They also motivate the use of alternatively angled layered panels for more construction design freedom, especially in areas that demand shear resistance. In addition, the design possibility that such 45°-configured CLT can carry a given load while using less material than conventional CLT suggests the potential to use such panels in a wider range of structural applications. The results of test production revealed that 45°-configured CLT can be industrially produced without using more material than is required for construction of conventional 90°-configured panels. Based on these results, CLT should be further explored as a suitable product for use in more wooden-panel construction.
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| 3. |
- Bridel, Claire, et al.
(författare)
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Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology : A Systematic Review and Meta-analysis
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:9, s. 1035-1048
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Forskningsöversikt (refereegranskat)abstract
- Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions.Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC.Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex.Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept.Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses.Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes.Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.
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| 4. |
- Lindenfors, Patrik, 1964-, et al.
(författare)
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The Cultural Evolution of Democracy : Saltational Changes in A Political Regime Landscape
- 2011
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Ingår i: PLOS ONE. - San Francisco : Public Library of Science. - 1932-6203. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- Transitions to democracy are most often considered the outcome of historical modernization processes. Socio-economic changes, such as increases in per capita GNP, education levels, urbanization and communication, have traditionally been found to be correlates or ‘requisites’ of democratic reform. However, transition times and the number of reform steps have not been studied comprehensively. Here we show that historically, transitions to democracy have mainly occurred through rapid leaps rather than slow and incremental transition steps, with a median time from autocracy to democracy of 2.4 years, and overnight in the reverse direction. Our results show that autocracy and democracy have acted as peaks in an evolutionary landscape of possible modes of institutional arrangements. Only scarcely have there been slow incremental transitions. We discuss our results in relation to the application of phylogenetic comparative methods in cultural evolution and point out that the evolving unit in this system is the institutional arrangement, not the individual country which is instead better regarded as the ‘host’ for the political system.
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| 5. |
- Nelson, Anders, 1969-, et al.
(författare)
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Labour-market orientation and approaches to studying — a study of the first Bologna Students at a Swedish Regional University
- 2017
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Ingår i: Studies in Higher Education. - Abingdon : Routledge. - 0307-5079 .- 1470-174X. ; 42:8, s. 1545-1566
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated labour-market orientations of students at a Swedish University with a dual/diverse focus on vocational/academic objectives. The aim was to investigate whether and how levels of students' labour-market orientation vary with social background, change during the study period, and are related to approaches to studying and achievements. The design was a multiple panel time-series study. Labour-market orientation was studied on the basis of locally designed questionnaires. Approaches to studying were analysed deductively in accordance with dimensions previously found by Study Process Questionnaires and inductively using a principal component analysis. Results suggest that labour-market orientations co-varied to a higher degree with the study programme than with social background. Contrary to what was hypothesized, being labour-market oriented was only moderately related to surface-oriented approaches to studying. It is suggested that future research should pay more attention to disciplinary traditions and local teacher and programme cultures in understanding developmental paths in labour-market orientation. © 2015 Society for Research into Higher Education
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| 6. |
- Rånge, Max, 1975-, et al.
(författare)
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“Civilizations” and Political-Institutional Paths : A Sequence Analysis of the MaxRange2 Data Set, 1789 – 2013
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In what sequences have nations changed institutionally in history and does that order matter for later democratization? If so, are there historical-institutional pathways of “civilizations”? These previously neglected research problems are addressed in this paper on the basis of a new, unique, and enormous data set tracking all political institutions and systems in the world monthly since 1789. The aim is both empirical and theoretical: to take steps toward an understanding of the sequential aspects of political-institutional evolution. Results visualize sequences at regime level that show few signs of path dependency. They also show that democracy may emerge in all types of regimes, though at varying paces. Separating religious-majority nations, Muslim systems are less affected by democracy diffusion than other religious-majority nations. Muslim political systems also exhibit larger regime type unpredictability. Taken together with estimates of GDP per capita, majority religions explain a minor share of discrepancies between regime types: wealth of nations is more important than majority religion on a general, regime type diversity level. However, specifications of institutional details will have to be made in future research in this new area of historical political-institutional study.
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| 8. |
- Rånge, Max, 1975-, et al.
(författare)
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Introducing the MaxRange Dataset : Monthly Data on Political Institutions and Regimes Since 1789 and Yearly Since 1600
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The MaxRange dataset provides information on political institutions for all countries of the world going back to 1789 on a monthly and yearly basis, and to 1600 on a yearly one. The yearly dataset spanning 1600 to 2014 has over 90,000 country-year observations, and in its monthly format from 1789 has over 660,000 observations. The time-series data are at least 200 years longer than any other comparable time-series dataset on political institutions. Created by Max Rånge, the datasets aggregate specific attributes to create nominal and ordinal rankings of political regimes on a 1-100 scale (the MaxRange1 dataset) and on a 1-1,000 scale (the MaxRange2 dataset). At the same time, however, the codes for each attribute underlying the categorization of political regimes are also included. It is more detailed than any other dataset on political institutions, yielding up to 1,000 different unique combinations of institutional features. In addition to supporting a rigorous classification of democratic and nondemocratic regimes, the dataset allows researchers to exploit institutional variation and to explore alternative ways of aggregating political institutions. The MaxRange dataset on political institutions is by far the biggest and most comprehensive political regime dataset to date, and it offers several advantages compared to other available data. In particular, the availability of monthly time-series data provides greater detail and reliability to support more accurate research on political transitions.
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| 9. |
- Rånge, Max, 1975-, et al.
(författare)
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Political Cultures as Context of Civic and Citizenship Education
- 2017
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Ingår i: 7th IEA International Research Conference: Researching education, improving learning. ; , s. 51-51
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Konferensbidrag (refereegranskat)abstract
- The overarching aim in this paper is to contextualize civic and citizenship education practices, something which promises to settle an old social scientific dispute about the sources of trust in institutions: Is trust in institutions rooted in social psychology, culture and socioeconomic factors, or is it a response to institutional performance? Here, we analyze ICCS 2009 (International Civic and Citizenship Education Study) data at student level (approximately 140,000 students) in 37 countries and territories merged with the 2009 Quality of Government dataset that includes the World Values Surveys (WVS) national aggregates on trust and confidence. We also added MaxRange institutional data for 2009. First, a regression tree analysis is made, second a series of orindary least squares (OLS) regressions, and third, a structural equation model. Results strongly support the institutional performance theory and further explains the interaction between the political institutions and the political culture. In fact the former make possible the latter, so that attitudes and participation may be critical to established institutions while taking part in them. Influences on trust in institutions thus exist on all three levels investigated: institutional, cultural and individual-psychological. However, the interacting political-institutional and political-cultural influences dominate.
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| 10. |
- Rånge, Max, 1975-, et al.
(författare)
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Political Institutions and Regimes since 1600 : A New Historical Data Set
- 2017
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Ingår i: Journal of Interdisciplinary History. - Cambridge : MIT Press. - 0022-1953 .- 1530-9169. ; 47:4, s. 495-520
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Tidskriftsartikel (refereegranskat)abstract
- A new data set provides vital information about the world’s political institutions, from 1789 on a monthly and yearly basis and from 1600 on a yearly basis. The yearly data set from 1600 has more than 90,000 country–year observations, and the monthly data set from 1789 more than 600,000 observations—by far the most comprehensive to date, offering several advantages over other available ones. The data set aggregates specific attributes to create nominal and ordinal rankings of political regimes on a scale of 1 to 1,000. In addition to supporting a rigorous classification of democratic and nondemocratic regimes, it allows researchers to trace institutional variations and to explore alternative ways of aggregating political institutions. As a research instrument, the MaxRange data set permits historically minded scholars to address a number of issues related to the dynamics of political institutions in an unprecedented manner. © 2017 by the Massachusetts Institute of Technology and The Journal of Interdisciplinary History, Inc.
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