283 results on '"Engelfriet P"'
Search Results
2. Potential determinants of antibody responses after vaccination against SARS-CoV-2 in older persons: the Doetinchem Cohort Study
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Yunus Kuijpers, H. Susan J. Picavet, Lia de Rond, Mary-lène de Zeeuw-Brouwer, Ryanne Rutkens, Esther Gijsbers, Irene Slits, Peter Engelfriet, Anne-Marie Buisman, and W. M. Monique Verschuren
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COVID-19 vaccination ,Antibody responses ,Age ,Frailty ,Comorbidity ,Lifestyle deficits ,Immunologic diseases. Allergy ,RC581-607 ,Geriatrics ,RC952-954.6 - Abstract
Abstract Background Immune responses to vaccination vary widely between individuals. The aim of this study was to identify health-related variables potentially underlying the antibody responses to SARS-CoV-2 vaccination in older persons. We recruited participants in the long-running Doetinchem Cohort Study (DCS) who underwent vaccination as part of the national COVID-19 program, and measured antibody concentrations to SARS-CoV-2 Spike protein (S1) and Nucleoprotein (N) at baseline (T0), and a month after both the first vaccination (T1), and the second vaccination (T2). Associations between the antibody concentrations and demographic variables, including age, sex, socio-economic status (SES), comorbidities (cardiovascular diseases and immune mediated diseases), various health parameters (cardiometabolic markers, inflammation markers, kidney- and lung function) and a composite measure of frailty (‘frailty index’, ranging from 0 to 1) were tested using multivariate models. Results We included 1457 persons aged 50 to 92 years old. Of these persons 1257 were infection naïve after their primary vaccination series. The majority (N = 954) of these individuals were vaccinated with two doses of BNT162b2 (Pfizer) and their data were used for further analysis. A higher frailty index was associated with lower anti-S1 antibody responses at T1 and T2 for both men (R T1 = -0.095, P T1 = 0.05; R T2 = -0.11, P T2 = 0.02) and women (R T1 = -0.24, P T1
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- 2023
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3. Computability by Monadic Second-Order Logic
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Engelfriet, Joost
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Computer Science - Formal Languages and Automata Theory - Abstract
A binary relation on graphs is recursively enumerable if and only if it can be computed by a formula in monadic second-order logic. The latter means that the formula defines a set of graphs, in the usual way, such that each "computation graph" in that set determines a pair consisting of an input graph and an output graph., Comment: 12 pages, 4 figures, to appear in Information Processing Letters
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- 2020
4. Neighbourhood socioeconomic inequalities in incidence of acute myocardial infarction: a cohort study quantifying age- and gender-specific differences in relative and absolute terms
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Koopman Carla, van Oeffelen Aloysia AM, Bots Michiel L, Engelfriet Peter M, Verschuren WM, van Rossem Lenie, van Dis Ineke, Capewell Simon, and Vaartjes Ilonca
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Coronary heart disease ,Acute myocardial infarction ,Incidence ,Socioeconomic status ,Relative ,Absolute ,The Netherlands ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Socioeconomic status has a profound effect on the risk of having a first acute myocardial infarction (AMI). Information on socioeconomic inequalities in AMI incidence across age- gender-groups is lacking. Our objective was to examine socioeconomic inequalities in the incidence of AMI considering both relative and absolute measures of risk differences, with a particular focus on age and gender. Methods We identified all patients with a first AMI from 1997 to 2007 through linked hospital discharge and death records covering the Dutch population. Relative risks (RR) of AMI incidence were estimated by mean equivalent household income at neighbourhood-level for strata of age and gender using Poisson regression models. Socioeconomic inequalities were also shown within the stratified age-gender groups by calculating the total number of events attributable to socioeconomic disadvantage. Results Between 1997 and 2007, 317,564 people had a first AMI. When comparing the most deprived socioeconomic quintile with the most affluent quintile, the overall RR for AMI was 1.34 (95 % confidence interval (CI): 1.32 – 1.36) in men and 1.44 (95 % CI: 1.42 – 1.47) in women. The socioeconomic gradient decreased with age. Relative socioeconomic inequalities were most apparent in men under 35 years and in women under 65 years. The largest number of events attributable to socioeconomic inequalities was found in men aged 45–74 years and in women aged 65–84 years. The total proportion of AMIs that was attributable to socioeconomic inequalities in the Dutch population of 1997 to 2007 was 14 % in men and 18 % in women. Conclusions Neighbourhood socioeconomic inequalities were observed in AMI incidence in the Netherlands, but the magnitude across age-gender groups depended on whether inequality was expressed in relative or absolute terms. Relative socioeconomic inequalities were high in young persons and women, where the absolute burden of AMI was low. Absolute socioeconomic inequalities in AMI were highest in the age-gender groups of middle-aged men and elderly women, where the number of cases was largest.
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- 2012
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5. Co-occurrence of diabetes, myocardial infarction, stroke, and cancer: quantifying age patterns in the Dutch population using health survey data
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van de Kassteele Jan, Boshuizen Hendriek C, Engelfriet Peter M, van Baal Pieter H, Schellevis Francois G, and Hoogenveen Rudolf T
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multimorbidity ,comorbidity ,diabetes ,cancer ,cardiovascular disease ,stroke ,P-splines ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background The high prevalence of chronic diseases in Western countries implies that the presence of multiple chronic diseases within one person is common. Especially at older ages, when the likelihood of having a chronic disease increases, the co-occurrence of distinct diseases will be encountered more frequently. The aim of this study was to estimate the age-specific prevalence of multimorbidity in the general population. In particular, we investigate to what extent specific pairs of diseases cluster within people and how this deviates from what is to be expected under the assumption of the independent occurrence of diseases (i.e., sheer coincidence). Methods We used data from a Dutch health survey to estimate the prevalence of pairs of chronic diseases specified by age. Diseases we focused on were diabetes, myocardial infarction, stroke, and cancer. Multinomial P-splines were fitted to the data to model the relation between age and disease status (single versus two diseases). To assess to what extent co-occurrence cannot be explained by independent occurrence, we estimated observed/expected co-occurrence ratios using predictions of the fitted regression models. Results Prevalence increased with age for all disease pairs. For all disease pairs, prevalence at most ages was much higher than is to be expected on the basis of coincidence. Observed/expected ratios of disease combinations decreased with age. Conclusion Common chronic diseases co-occur in one individual more frequently than is due to chance. In monitoring the occurrence of diseases among the population at large, such multimorbidity is insufficiently taken into account.
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- 2011
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6. Estimating and comparing incidence and prevalence of chronic diseases by combining GP registry data: the role of uncertainty
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van den Dungen Catharina, Poos Marinus J, Hoogenveen Rudolf T, Engelfriet Peter M, van Baal Pieter H, and Boshuizen Hendriek C
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incidence ,prevalence ,Monte Carlo simulation ,uncertainty ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Estimates of disease incidence and prevalence are core indicators of public health. The manner in which these indicators stand out against each other provide guidance as to which diseases are most common and what health problems deserve priority. Our aim was to investigate how routinely collected data from different general practitioner registration networks (GPRNs) can be combined to estimate incidence and prevalence of chronic diseases and to explore the role of uncertainty when comparing diseases. Methods Incidence and prevalence counts, specified by gender and age, of 18 chronic diseases from 5 GPRNs in the Netherlands from the year 2007 were used as input. Generalized linear mixed models were fitted with the GPRN identifier acting as random intercept, and age and gender as explanatory variables. Using predictions of the regression models we estimated the incidence and prevalence for 18 chronic diseases and calculated a stochastic ranking of diseases in terms of incidence and prevalence per 1,000. Results Incidence was highest for coronary heart disease and prevalence was highest for diabetes if we looked at the point estimates. The between GPRN variance in general was higher for incidence than for prevalence. Since uncertainty intervals were wide for some diseases and overlapped, the ranking of diseases was subject to uncertainty. For incidence shifts in rank of up to twelve positions were observed. For prevalence, most diseases shifted maximally three or four places in rank. Conclusion Estimates of incidence and prevalence can be obtained by combining data from GPRNs. Uncertainty in the estimates of absolute figures may lead to different rankings of diseases and, hence, should be taken into consideration when comparing disease incidences and prevalences.
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- 2011
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7. A B\'uchi-Elgot-Trakhtenbrot theorem for automata with MSO graph storage
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Engelfriet, Joost and Vogler, Heiko
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Computer Science - Formal Languages and Automata Theory - Abstract
We introduce MSO graph storage types, and call a storage type MSO-expressible if it is isomorphic to some MSO graph storage type. An MSO graph storage type has MSO-definable sets of graphs as storage configurations and as storage transformations. We consider sequential automata with MSO graph storage and associate with each such automaton a string language (in the usual way) and a graph language; a graph is accepted by the automaton if it represents a correct sequence of storage configurations for a given input string. For each MSO graph storage type, we define an MSO logic which is a subset of the usual MSO logic on graphs. We prove a B\"uchi-Elgot-Trakhtenbrot theorem, both for the string case and the graph case. Moreover, we prove that (i) each MSO graph transduction can be used as storage transformation in an MSO graph storage type, (ii) every automatic storage type is MSO-expressible, and (iii) the pushdown operator on storage types preserves the property of MSO-expressibility. Thus, the iterated pushdown storage types are MSO-expressible.
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- 2019
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8. Linear Bounded Composition of Tree-Walking Tree Transducers: Linear Size Increase and Complexity
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Engelfriet, Joost, Inaba, Kazuhiro, and Maneth, Sebastian
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Computer Science - Formal Languages and Automata Theory - Abstract
Compositions of tree-walking tree transducers form a hierarchy with respect to the number of transducers in the composition. As main technical result it is proved that any such composition can be realized as a linear bounded composition, which means that the sizes of the intermediate results can be chosen to be at most linear in the size of the output tree. This has consequences for the expressiveness and complexity of the translations in the hierarchy. First, if the computed translation is a function of linear size increase, i.e., the size of the output tree is at most linear in the size of the input tree, then it can be realized by just one, deterministic, tree-walking tree transducer. For compositions of deterministic transducers it is decidable whether or not the translation is of linear size increase. Second, every composition of deterministic transducers can be computed in deterministic linear time on a RAM and in deterministic linear space on a Turing machine, measured in the sum of the sizes of the input and output tree. Similarly, every composition of nondeterministic transducers can be computed in simultaneous polynomial time and linear space on a nondeterministic Turing machine. Their output tree languages are deterministic context-sensitive, i.e., can be recognized in deterministic linear space on a Turing machine. The membership problem for compositions of nondeterministic translations is nondeterministic polynomial time and deterministic linear space. The membership problem for the composition of a nondeterministic and a deterministic tree-walking tree translation (for a nondeterministic IO macro tree translation) is log-space reducible to a context-free language, whereas the membership problem for the composition of a deterministic and a nondeterministic tree-walking tree translation (for a nondeterministic OI macro tree translation) is possibly NP-complete.
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- 2019
9. XML Navigation and Transformation by Tree-Walking Automata and Transducers with Visible and Invisible Pebbles
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Engelfriet, Joost, Hoogeboom, Hendrik Jan, and Samwel, Bart
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Computer Science - Formal Languages and Automata Theory - Abstract
The pebble tree automaton and the pebble tree transducer are enhanced by additionally allowing an unbounded number of "invisible" pebbles (as opposed to the usual "visible" ones). The resulting pebble tree automata recognize the regular tree languages (i.e., can validate all generalized DTD's) and hence can find all matches of MSO definable patterns. Moreover, when viewed as a navigational device, they lead to an XPath-like formalism that has a path expression for every MSO definable binary pattern. The resulting pebble tree transducers can apply arbitrary MSO definable tests to (the observable part of) their configurations, they (still) have a decidable typechecking problem, and they can model the recursion mechanism of XSLT. The time complexity of the typechecking problem for conjunctive queries that use MSO definable patterns can often be reduced through the use of invisible pebbles., Comment: 96 pages, 6 figures, 7 tables
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- 2018
10. Impaired JAK-STAT pathway signaling in leukocytes of the frail elderly
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Samson, Leonard Daniël, Engelfriet, Peter, Verschuren, W. M. Monique, Picavet, H. Susan J., Ferreira, José A., de Zeeuw-Brouwer, Mary-lène, Buisman, Anne-Marie, and Boots, A. Mieke H.
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- 2022
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11. The Trees of Hanoi
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Engelfriet, Joost
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Computer Science - Formal Languages and Automata Theory ,Computer Science - Data Structures and Algorithms ,Mathematics - History and Overview - Abstract
The game of the Towers of Hanoi is generalized to binary trees. First, a straightforward solution of the game is discussed. Second, a shorter solution is presented, which is then shown to be optimal., Comment: 11 pages, slightly revised version of a note from 1981
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- 2017
12. Multiple Context-Free Tree Grammars: Lexicalization and Characterization
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Engelfriet, Joost, Maletti, Andreas, and Maneth, Sebastian
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Computer Science - Formal Languages and Automata Theory ,Computer Science - Computation and Language ,68Q45 ,F.4.2 ,F.4.3 - Abstract
Multiple (simple) context-free tree grammars are investigated, where "simple" means "linear and nondeleting". Every multiple context-free tree grammar that is finitely ambiguous can be lexicalized; i.e., it can be transformed into an equivalent one (generating the same tree language) in which each rule of the grammar contains a lexical symbol. Due to this transformation, the rank of the nonterminals increases at most by 1, and the multiplicity (or fan-out) of the grammar increases at most by the maximal rank of the lexical symbols; in particular, the multiplicity does not increase when all lexical symbols have rank 0. Multiple context-free tree grammars have the same tree generating power as multi-component tree adjoining grammars (provided the latter can use a root-marker). Moreover, every multi-component tree adjoining grammar that is finitely ambiguous can be lexicalized. Multiple context-free tree grammars have the same string generating power as multiple context-free (string) grammars and polynomial time parsing algorithms. A tree language can be generated by a multiple context-free tree grammar if and only if it is the image of a regular tree language under a deterministic finite-copying macro tree transducer. Multiple context-free tree grammars can be used as a synchronous translation device., Comment: 78 pages, 13 figures
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- 2017
13. Impaired JAK-STAT pathway signaling in leukocytes of the frail elderly
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Leonard Daniël Samson, Peter Engelfriet, W. M. Monique Verschuren, H. Susan J. Picavet, José A. Ferreira, Mary-lène de Zeeuw-Brouwer, Anne-Marie Buisman, and A. Mieke H. Boots
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Immunosenescence ,Frailty ,JAK-STAT pathway ,Immune function ,Phospho-flow cytometry ,Chronic low-grade inflammation ,Immunologic diseases. Allergy ,RC581-607 ,Geriatrics ,RC952-954.6 - Abstract
Abstract Background Elderly often show reduced immune functioning and can develop chronic low-grade inflammation. Why some elderly are more prone to become frail is unknown. We investigated whether frailty is associated with altered cytokine signaling through the JAK-STAT pathway in leukocytes of 34 individuals aged 65–74 years. In addition, we investigated how this relation is affected by chronic low-grade inflammation during the previous 20 years. Cytokine signaling was quantified by measuring intracellular STAT1, STAT3, and STAT5 phosphorylation in monocytes, B cells, CD4+ T cells and CD8+ T cells upon stimulation with IL-2, IL-6, IL-10, IFNα and IFNγ, using phospho-flow cytometry. Presence of chronic low-grade inflammation was investigated by evaluating 18 different plasma inflammatory markers that had been measured repeatedly in the same individuals over the previous 20 years. Frailty was assessed as a score on a frailty index. Results We found that lower cytokine-induced pSTAT responsiveness in the various cell subsets was seen with higher frailty scores in both men and women, indicative of dysfunctional pSTAT responses in frailer individuals. Associations differed between men and women, with frailer women showing lower pSTAT1 responses in monocytes and frailer men showing lower pSTAT5 responses in CD4+ and CD8+ T cells. Notably, lower IL-10-induced pSTAT3 responses in men were related to both higher frailty scores and higher CRP levels over the past 20 years. This might indicate poor resolution of low-grade inflammation due to defective regulatory pSTAT signaling in older men. Conclusions Our results emphasize the importance of preserved JAK-STAT pathway signaling in healthy aging and reveal cellular pSTAT levels as a candidate biomarker of frailty.
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- 2022
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14. Characterization of the biochemical activity and tumor-promoting role of the dual protein methyltransferase METL-13/METTL13 in Caenorhabditis elegans
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Melanie L. Engelfriet, Jędrzej M. Małecki, Anna F. Forsberg, Pål Ø. Falnes, and Rafal Ciosk
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Medicine ,Science - Abstract
The methyltransferase-like protein 13 (METTL13) methylates the eukaryotic elongation factor 1 alpha (eEF1A) on two locations: the N-terminal amino group and lysine 55. The absence of this methylation leads to reduced protein synthesis and cell proliferation in human cancer cells. Previous studies showed that METTL13 is dispensable in non-transformed cells, making it potentially interesting for cancer therapy. However, METTL13 has not been examined yet in whole animals. Here, we used the nematode Caenorhabditis elegans as a simple model to assess the functions of METTL13. Using methyltransferase assays and mass spectrometry, we show that the C. elegans METTL13 (METL-13) methylates eEF1A (EEF-1A) in the same way as the human protein. Crucially, the cancer-promoting role of METL-13 is also conserved and depends on the methylation of EEF-1A, like in human cells. At the same time, METL-13 appears dispensable for animal growth, development, and stress responses. This makes C. elegans a convenient whole-animal model for studying METL13-dependent carcinogenesis without the complications of interfering with essential wild-type functions.
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- 2023
15. Healthy lifestyle over the life course: Population trends and individual changes over 30 years of the Doetinchem Cohort Study
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Edith E. Schermer, Peter M. Engelfriet, Anneke Blokstra, W. M. Monique Verschuren, and H. Susan J. Picavet
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lifestyle and behavior ,cohort ,trends ,overweight and obesity ,physical activity ,sleep ,Public aspects of medicine ,RA1-1270 - Abstract
For five health-related lifestyle factors (physical activity, weight, smoking, sleep, and alcohol consumption) we describe both population trends and individual changes over a period of 30 years in the same adult population. Dichotomous indicators (healthy/unhealthy) of lifestyle were analyzed for 3,139 participants measured every 5 years in the Doetinchem Cohort Study (1987–2017). Population trends over 30 years in physical inactivity and “unhealthy” alcohol consumption were flat (i.e., stable); overweight and unhealthy sleep prevalence increased; smoking prevalence decreased. The proportion of the population being healthy on all five lifestyle factors declined from 17% in the round 1 to 10.8% in round 6. Underlying these trends a dynamic pattern of changes at the individual level was seen: sleep duration and physical activity level changed in almost half of the individuals; Body Mass Index (BMI) and alcohol consumption in one-third; smoking in one-fourth. Population trends don't give insight into change at the individual level. In order to be able to gauge the potential for change of health-related lifestyle, it is important to take changes at the individual level into account.
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- 2022
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16. Tree Automata and Tree Grammars
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Engelfriet, Joost
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Computer Science - Formal Languages and Automata Theory - Abstract
Lecture notes on tree language theory, in particular recognizable tree languages and finite state tree transformations., Comment: 76 pages, slightly revised version of lecture notes from 1975
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- 2015
17. Linear-bounded composition of tree-walking tree transducers: linear size increase and complexity
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Engelfriet, Joost, Inaba, Kazuhiro, and Maneth, Sebastian
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- 2021
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18. Context-Free Grammars with Storage
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Engelfriet, Joost
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Computer Science - Formal Languages and Automata Theory - Abstract
Context-free S grammars are introduced, for arbitrary (storage) type S, as a uniform framework for recursion-based grammars, automata, and transducers, viewed as programs. To each occurrence of a nonterminal of a context-free S grammar an object of type S is associated, that can be acted upon by tests and operations, as indicated in the rules of the grammar. Taking particular storage types gives particular formalisms, such as indexed grammars, top-down tree transducers, attribute grammars, etc. Context-free S grammars are equivalent to pushdown S automata. The context-free S languages can be obtained from the deterministic one-way S automaton languages by way of the delta operations on languages, introduced in this paper., Comment: 58 pages, 8 figures, slightly revised version of a report from 1986
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- 2014
19. Look-Ahead Removal for Top-Down Tree Transducers
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Engelfriet, Joost, Maneth, Sebastian, and Seidl, Helmut
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Computer Science - Formal Languages and Automata Theory ,68Q05, 68Q45 ,F.1.1 ,F.4.3 - Abstract
Top-down tree transducers are a convenient formalism for describing tree transformations. They can be equipped with regular look-ahead, which allows them to inspect a subtree before processing it. In certain cases, such a look-ahead can be avoided and the transformation can be realized by a transducer without look-ahead. Removing the look-ahead from a transducer, if possible, is technically highly challenging. For a restricted class of transducers with look-ahead, namely those that are total, deterministic, ultralinear, and bounded erasing, we present an algorithm that, for a given transducer from that class, (1) decides whether it is equivalent to a total deterministic transducer without look-ahead, and (2) constructs such a transducer if the answer is positive. For the whole class of total deterministic transducers with look-ahead we present a similar algorithm, which assumes that a so-called difference bound is known for the given transducer. The designer of a transducer can usually also determine a difference bound for it., Comment: 57 pages, to appear in TCS
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- 2013
20. Inflammatory marker trajectories associated with frailty and ageing in a 20‐year longitudinal study
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Leonard Daniël Samson, Anne‐Marie Buisman, José A Ferreira, H Susan J Picavet, W M Monique Verschuren, Annemieke MH Boots, and Peter Engelfriet
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chemokines ,chronic low‐grade inflammation ,cytokines ,frailty ,healthy ageing ,longitudinal study ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Abstract Objective The aim of this exploratory study was to investigate the development of low‐grade inflammation during ageing and its relationship with frailty. Methods The trajectories of 18 inflammatory markers measured in blood samples, collected at 5‐year intervals over a period of 20 years from 144 individuals aged 65–75 years at the study endpoint, were related to the degree of frailty later in life. Results IFN‐γ‐related markers and platelet activation markers were found to change in synchrony. Chronically elevated levels of IL‐6 pathway markers, such as CRP and sIL‐6R, were associated with more frailty, poorer lung function and reduced physical strength. Being overweight was a possible driver of these associations. More and stronger associations were detected in women, such as a relation between increasing sCD14 levels and frailty, indicating a possible role for monocyte overactivation. Multivariate prediction of frailty confirmed the main results, but predictive accuracy was low. Conclusion In summary, we documented temporal changes in and between inflammatory markers in an ageing population over a period of 20 years, and related these to clinically relevant health outcomes.
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- 2022
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21. Automata with Nested Pebbles Capture First-Order Logic with Transitive Closure
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Engelfriet, Joost and Hoogeboom, Hendrik Jan
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Computer Science - Logic in Computer Science ,F.1.1 ,F.4.1 ,F.4.3 - Abstract
String languages recognizable in (deterministic) log-space are characterized either by two-way (deterministic) multi-head automata, or following Immerman, by first-order logic with (deterministic) transitive closure. Here we elaborate this result, and match the number of heads to the arity of the transitive closure. More precisely, first-order logic with k-ary deterministic transitive closure has the same power as deterministic automata walking on their input with k heads, additionally using a finite set of nested pebbles. This result is valid for strings, ordered trees, and in general for families of graphs having a fixed automaton that can be used to traverse the nodes of each of the graphs in the family. Other examples of such families are grids, toruses, and rectangular mazes. For nondeterministic automata, the logic is restricted to positive occurrences of transitive closure. The special case of k=1 for trees, shows that single-head deterministic tree-walking automata with nested pebbles are characterized by first-order logic with unary deterministic transitive closure. This refines our earlier result that placed these automata between first-order and monadic second-order logic on trees., Comment: Paper for Logical Methods in Computer Science, 27 pages, 1 figure
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- 2007
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22. The Equivalence Problem for Deterministic MSO Tree Transducers is Decidable
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Engelfriet, Joost and Maneth, Sebastian
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Computer Science - Logic in Computer Science - Abstract
It is decidable for deterministic MSO definable graph-to-string or graph-to-tree transducers whether they are equivalent on a context-free set of graphs.
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- 2005
23. A B\'uchi-Elgot-Trakhtenbrot theorem for automata with MSO graph storage
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Joost Engelfriet and Heiko Vogler
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computer science - formal languages and automata theory ,Mathematics ,QA1-939 - Abstract
We introduce MSO graph storage types, and call a storage type MSO-expressible if it is isomorphic to some MSO graph storage type. An MSO graph storage type has MSO-definable sets of graphs as storage configurations and as storage transformations. We consider sequential automata with MSO graph storage and associate with each such automaton a string language (in the usual way) and a graph language; a graph is accepted by the automaton if it represents a correct sequence of storage configurations for a given input string. For each MSO graph storage type, we define an MSO logic which is a subset of the usual MSO logic on graphs. We prove a B\"uchi-Elgot-Trakhtenbrot theorem, both for the string case and the graph case. Moreover, we prove that (i) each MSO graph transduction can be used as storage transformation in an MSO graph storage type, (ii) every automatic storage type is MSO-expressible, and (iii) the pushdown operator on storage types preserves the property of MSO-expressibility. Thus, the iterated pushdown storage types are MSO-expressible.
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- 2020
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24. MSO definable string transductions and two-way finite state transducers
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Engelfriet, Joost and Hoogeboom, Hendrik Jan
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Computer Science - Logic in Computer Science ,Computer Science - Computational Complexity ,F.4.1 ,F.4.3 ,F.1.1 - Abstract
String transductions that are definable in monadic second-order (mso) logic (without the use of parameters) are exactly those realized by deterministic two-way finite state transducers. Nondeterministic mso definable string transductions (i.e., those definable with the use of parameters) correspond to compositions of two nondeterministic two-way finite state transducers that have the finite visit property. Both families of mso definable string transductions are characterized in terms of Hennie machines, i.e., two-way finite state transducers with the finite visit property that are allowed to rewrite their input tape., Comment: 63 pages, LaTeX2e. Extended abstract presented at 26-th ICALP, 1999
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- 1999
25. Modeling the Cost-Effectiveness and Budgetary Impact for Subpopulations
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Nuijten, M. J. C., Kosa, J., and Engelfriet, P.
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- 2003
26. In-depth immune cellular profiling reveals sex-specific associations with frailty
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Samson, Leonard Daniël, Boots, A. Mieke H., Ferreira, José A., Picavet, H. Susan J., de Rond, Lia G. H., de Zeeuw-Brouwer, Mary-lène, Verschuren, W. M. Monique, Buisman, Anne-Marie, and Engelfriet, Peter
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- 2020
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27. Monotonicity and Persistence in Preferential Logics
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Engelfriet, J.
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Computer Science - Artificial Intelligence - Abstract
An important characteristic of many logics for Artificial Intelligence is their nonmonotonicity. This means that adding a formula to the premises can invalidate some of the consequences. There may, however, exist formulae that can always be safely added to the premises without destroying any of the consequences: we say they respect monotonicity. Also, there may be formulae that, when they are a consequence, can not be invalidated when adding any formula to the premises: we call them conservative. We study these two classes of formulae for preferential logics, and show that they are closely linked to the formulae whose truth-value is preserved along the (preferential) ordering. We will consider some preferential logics for illustration, and prove syntactic characterization results for them. The results in this paper may improve the efficiency of theorem provers for preferential logics., Comment: See http://www.jair.org/ for any accompanying files
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- 1997
28. A New Pipeline for the Normalization and Pooling of Metabolomics Data
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Vivian Viallon, Mathilde His, Sabina Rinaldi, Marie Breeur, Audrey Gicquiau, Bertrand Hemon, Kim Overvad, Anne Tjønneland, Agnetha Linn Rostgaard-Hansen, Joseph A. Rothwell, Lucie Lecuyer, Gianluca Severi, Rudolf Kaaks, Theron Johnson, Matthias B. Schulze, Domenico Palli, Claudia Agnoli, Salvatore Panico, Rosario Tumino, Fulvio Ricceri, W. M. Monique Verschuren, Peter Engelfriet, Charlotte Onland-Moret, Roel Vermeulen, Therese Haugdahl Nøst, Ilona Urbarova, Raul Zamora-Ros, Miguel Rodriguez-Barranco, Pilar Amiano, José Maria Huerta, Eva Ardanaz, Olle Melander, Filip Ottoson, Linda Vidman, Matilda Rentoft, Julie A. Schmidt, Ruth C. Travis, Elisabete Weiderpass, Mattias Johansson, Laure Dossus, Mazda Jenab, Marc J. Gunter, Justo Lorenzo Bermejo, Dominique Scherer, Reza M. Salek, Pekka Keski-Rahkonen, and Pietro Ferrari
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cancer epidemiology ,normalization ,pooling ,technical variability ,metabolomics ,metabolites ,Microbiology ,QR1-502 - Abstract
Pooling metabolomics data across studies is often desirable to increase the statistical power of the analysis. However, this can raise methodological challenges as several preanalytical and analytical factors could introduce differences in measured concentrations and variability between datasets. Specifically, different studies may use variable sample types (e.g., serum versus plasma) collected, treated, and stored according to different protocols, and assayed in different laboratories using different instruments. To address these issues, a new pipeline was developed to normalize and pool metabolomics data through a set of sequential steps: (i) exclusions of the least informative observations and metabolites and removal of outliers; imputation of missing data; (ii) identification of the main sources of variability through principal component partial R-square (PC-PR2) analysis; (iii) application of linear mixed models to remove unwanted variability, including samples’ originating study and batch, and preserve biological variations while accounting for potential differences in the residual variances across studies. This pipeline was applied to targeted metabolomics data acquired using Biocrates AbsoluteIDQ kits in eight case-control studies nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Comprehensive examination of metabolomics measurements indicated that the pipeline improved the comparability of data across the studies. Our pipeline can be adapted to normalize other molecular data, including biomarkers as well as proteomics data, and could be used for pooling molecular datasets, for example in international consortia, to limit biases introduced by inter-study variability. This versatility of the pipeline makes our work of potential interest to molecular epidemiologists.
- Published
- 2021
- Full Text
- View/download PDF
29. The impact of urban form on commuting in large Chinese cities
- Author
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Engelfriet, Lara and Koomen, Eric
- Published
- 2018
- Full Text
- View/download PDF
30. Composition Closure of Linear Extended Top-down Tree Transducers
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Engelfriet, Joost, Fülöp, Zoltán, and Maletti, Andreas
- Published
- 2017
- Full Text
- View/download PDF
31. Aging-related trajectories of lung function in the general population-The Doetinchem Cohort Study.
- Author
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Sandra H van Oostrom, Peter M Engelfriet, W M Monique Verschuren, Maarten Schipper, Inge M Wouters, Marike Boezen, Henriëtte A Smit, Huib A M Kerstjens, and H Susan J Picavet
- Subjects
Medicine ,Science - Abstract
The objective of this study was to explore trajectories of lung function decline with age in the general population, and to study the effect of sociodemographic and life style related risk factors, in particular smoking and BMI. For this purpose, we used data from the Doetinchem Cohort Study (DCS) of men and women, selected randomly from the general population and aged 20-59 years at inclusion in 1987-1991, and followed until the present. Participants in the DCS are assessed every five years. Spirometry has been performed as part of this assessment from 1994 onwards. Participants were included in this study if spirometric measurement of FEV1, which in this study was the main parameter of interest, was acceptable and reproducible on at least one measurement round, leading to the inclusion of 5727 individuals (3008 females). Statistical analysis revealed three typical trajectories. The majority of participants followed a trajectory that closely adhered to the Global Lung Initiative Reference values (94.9% of men and 96.4% of women). Two other trajectories showed a more pronounced decline. Smoking and the presence of respiratory complaints were the best predictors of a trajectory with stronger decline. A greater BMI over the follow-up period was associated with a more unfavorable FEV1 course both in men (β = -0.027 (SD = 0.002); P < 0.001) and in women (β = -0.008 (SD = 0.001); P < 0.001). Smokers at baseline who quit the habit during follow-up, showed smaller decline in FEV1 in comparison to persistent smokers, independent of BMI change (In men β = -0.074 (SD = 0.020); P < 0.001. In women β = -0.277 (SD = 0.068); P < 0.001). In conclusion, three typical trajectories of age-related FEV1 decline could be distinguished. Change in the lifestyle related risk factors, BMI and smoking, significantly impact aging-related decline of lung function. Identifying deviant trajectories may help in early recognition of those at risk of a diagnosis of lung disease later in life.
- Published
- 2018
- Full Text
- View/download PDF
32. Two-way pebble transducers for partial functions and their composition
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Engelfriet, Joost
- Published
- 2015
- Full Text
- View/download PDF
33. High-risk subtypes of chronic lymphocytic leukemia are detectable as early as 16 years prior to diagnosis
- Author
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Kolijn, P.M. Hosnijeh, F.S. Späth, F. Hengeveld, P.J. Agathangelidis, A. Saleh, M. Casabonne, D. Benavente, Y. Jerkeman, M. Agudo, A. Barricarte, A. Besson, C. Sánchez, M.-J. Chirlaque, M.-D. Masala, G. Sacerdote, C. Grioni, S. Schulze, M.B. Nieters, A. Engelfriet, P. Hultdin, M. McKay, J.D. Vermeulen, R.C.H. Langerak, A.W.
- Subjects
immune system diseases ,hemic and lymphatic diseases - Abstract
Chronic lymphocytic leukemia (CLL) is preceded by monoclonal B-cell lymphocytosis (MBL), a CLL precursor state with a prevalence of up to 12% in aged individuals; however, the duration of MBL and the mechanisms of its evolution to CLL remain largely unknown. In this study, we sequenced the B-cell receptor (BcR) immunoglobulin heavy chain (IGH) gene repertoire of 124 patients with CLL and 118 matched controls in blood samples taken up to 22 years prior to diagnosis. Significant skewing in the BcR IGH gene repertoire was detected in the majority of patients, even before the occurrence of lymphocytosis and irrespective of the clonotypic IGH variable gene somatic hypermutation status. Furthermore, we identified dominant clonotypes belonging to major stereotyped subsets associated with poor prognosis up to 16 years before diagnosis in 14 patients with CLL. In 22 patients with longitudinal samples, the skewing of the BcR IGH gene repertoire increased significantly over time to diagnosis or remained stable at high levels. For 14 of 16 patients with available samples at diagnosis, the CLL clonotype was already present in the prediagnostic samples. Overall, our data indicate that the preclinical phase of CLL could be longer than previously thought, even in adverse-prognostic cases. © 2022 American Society of Hematology
- Published
- 2022
34. Erratum to: “Top-down Tree Transducers with Regular Look-ahead”
- Author
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Engelfriet, Joost
- Published
- 2016
- Full Text
- View/download PDF
35. A new pipeline for the normalization and pooling of metabolomics data
- Author
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Viallon, V., His, M., Rinaldi, S., Breeur, M., Gicquiau, A., Hemon, B., Overvad, K., Tjønneland, A., Rostgaard-Hansen, A.L., Rothwell, J.A., Lecuyer, L., Severi, G., Kaaks, R., Johnson, T., Schulze, M.B., Palli, D., Agnoli, C., Panico, S., Tumino, R., Ricceri, F., Monique Verschuren, W.M., Engelfriet, P., Onland-Moret, C., Vermeulen, R., Nøst, T.H., Urbarova, I., Zamora-Ros, R., Rodriguez-Barranco, M., Amiano, P., Huerta, J.M., Ardanaz, E., Melander, O., Ottoson, F., Vidman, L., Rentoft, M., Schmidt, J.A., Travis, R.C., Weiderpass, E., Johansson, M., Dossus, L., Jenab, M., Gunter, M.J., Bermejo, J.L., Scherer, D., Salek, R.M., Keski-Rahkonen, P., Ferrari, P., IRAS OH Epidemiology Chemical Agents, dIRAS RA-2, Sub Inorganic Chemistry and Catalysis, IRAS OH Epidemiology Chemical Agents, dIRAS RA-2, and Sub Inorganic Chemistry and Catalysis
- Subjects
Normalization (statistics) ,Pooling ,Computer science ,Pipeline (computing) ,Endocrinology, Diabetes and Metabolism ,computer.software_genre ,Microbiology ,Biochemistry ,Generalized linear mixed model ,Statistical power ,Article ,03 medical and health sciences ,Endocrinology ,0302 clinical medicine ,Cancer epidemiology ,Metabolites ,Metabolomics ,Imputation (statistics) ,Càncer ,Molecular Biology ,030304 developmental biology ,Cancer ,0303 health sciences ,Cancer och onkologi ,Bioinformatics (Computational Biology) ,Normalization ,Technical variability ,VDP::Medisinske Fag: 700::Helsefag: 800::Samfunnsmedisin, sosialmedisin: 801 ,Missing data ,QR1-502 ,3. Good health ,Diabetes and Metabolism ,Metabolòmica ,030220 oncology & carcinogenesis ,Cancer and Oncology ,Outlier ,Bioinformatik (beräkningsbiologi) ,Data mining ,VDP::Medical disciplines: 700::Health sciences: 800::Community medicine, Social medicine: 801 ,computer - Abstract
Pooling metabolomics data across studies is often desirable to increase the statistical power of the analysis. However, this can raise methodological challenges as several preanalytical and analytical factors could introduce differences in measured concentrations and variability between datasets. Specifically, different studies may use variable sample types (e.g., serum versus plasma) collected, treated, and stored according to different protocols, and assayed in different laboratories using different instruments. To address these issues, a new pipeline was developed to normalize and pool metabolomics data through a set of sequential steps: (i) exclusions of the least informative observations and metabolites and removal of outliers, imputation of missing data, (ii) identification of the main sources of variability through principal component partial R-square (PC-PR2) analysis, (iii) application of linear mixed models to remove unwanted variability, including samples’ originating study and batch, and preserve biological variations while accounting for potential differences in the residual variances across studies. This pipeline was applied to targeted metabolomics data acquired using Biocrates AbsoluteIDQ kits in eight case-control studies nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Comprehensive examination of metabolomics measurements indicated that the pipeline improved the comparability of data across the studies. Our pipeline can be adapted to normalize other molecular data, including biomarkers as well as proteomics data, and could be used for pooling molecular datasets, for example in international consortia, to limit biases introduced by inter-study variability. This versatility of the pipeline makes our work of potential interest to molecular epidemiologists.
- Published
- 2021
36. Comparing ischaemic stroke in six European countries. The EuroHOPE register study
- Author
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Malmivaara, A., Meretoja, A., Peltola, M., Numerato, D., Heijink, R., Engelfriet, P., Wild, S. H., Belicza, É., Bereczki, D., Medin, E., Goude, F., Boncoraglio, G., Tatlisumak, T., Seppälä, T., and Häkkinen, U.
- Published
- 2015
- Full Text
- View/download PDF
37. Referentiekader spreiding en beschikbaarheid ambulancezorg 2021
- Author
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Kommer, GJ, Engelfriet, P, and Over, E
- Published
- 2021
- Full Text
- View/download PDF
38. A New Pipeline for the Normalization and Pooling of Metabolomics Data
- Author
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IRAS OH Epidemiology Chemical Agents, dIRAS RA-2, Sub Inorganic Chemistry and Catalysis, Viallon, V., His, M., Rinaldi, S., Breeur, M., Gicquiau, A., Hemon, B., Overvad, K., Tjønneland, A., Rostgaard-Hansen, A.L., Rothwell, J.A., Lecuyer, L., Severi, G., Kaaks, R., Johnson, T., Schulze, M.B., Palli, D., Agnoli, C., Panico, S., Tumino, R., Ricceri, F., Monique Verschuren, W.M., Engelfriet, P., Onland-Moret, C., Vermeulen, R., Nøst, T.H., Urbarova, I., Zamora-Ros, R., Rodriguez-Barranco, M., Amiano, P., Huerta, J.M., Ardanaz, E., Melander, O., Ottoson, F., Vidman, L., Rentoft, M., Schmidt, J.A., Travis, R.C., Weiderpass, E., Johansson, M., Dossus, L., Jenab, M., Gunter, M.J., Bermejo, J.L., Scherer, D., Salek, R.M., Keski-Rahkonen, P., Ferrari, P., IRAS OH Epidemiology Chemical Agents, dIRAS RA-2, Sub Inorganic Chemistry and Catalysis, Viallon, V., His, M., Rinaldi, S., Breeur, M., Gicquiau, A., Hemon, B., Overvad, K., Tjønneland, A., Rostgaard-Hansen, A.L., Rothwell, J.A., Lecuyer, L., Severi, G., Kaaks, R., Johnson, T., Schulze, M.B., Palli, D., Agnoli, C., Panico, S., Tumino, R., Ricceri, F., Monique Verschuren, W.M., Engelfriet, P., Onland-Moret, C., Vermeulen, R., Nøst, T.H., Urbarova, I., Zamora-Ros, R., Rodriguez-Barranco, M., Amiano, P., Huerta, J.M., Ardanaz, E., Melander, O., Ottoson, F., Vidman, L., Rentoft, M., Schmidt, J.A., Travis, R.C., Weiderpass, E., Johansson, M., Dossus, L., Jenab, M., Gunter, M.J., Bermejo, J.L., Scherer, D., Salek, R.M., Keski-Rahkonen, P., and Ferrari, P.
- Published
- 2021
39. A New Pipeline for the Normalization and Pooling of Metabolomics Data
- Author
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Viallon, V, His, M, Rinaldi, S, Breeur, M, Gicquiau, A, Hemon, B, Overvad, K, Tjonneland, A, Rostgaard-Hansen, AL, Rothwell, JA, Lecuyer, L, Severi, G, Kaaks, R, Johnson, T, Schulze, MB, Palli, D, Agnoli, C, Panico, S, Tumino, R, Ricceri, F, Verschuren, WMM, Engelfriet, P, Onland-Moret, C, Vermeulen, R, Nost, TH, Urbarova, I, Zamora-Ros, R, Rodriguez-Barranco, M, Amiano, P, Huerta, JM, Ardanaz, E, Melander, O, Ottoson, F, Vidman, L, Rentoft, M, Schmidt, JA, Travis, RC, Weiderpass, E, Johansson, M, Dossus, L, Jenab, M, Gunter, MJ, Bermejo, JL, Scherer, D, Salek, RM, Keski-Rahkonen, P, Ferrari, P, Viallon, V, His, M, Rinaldi, S, Breeur, M, Gicquiau, A, Hemon, B, Overvad, K, Tjonneland, A, Rostgaard-Hansen, AL, Rothwell, JA, Lecuyer, L, Severi, G, Kaaks, R, Johnson, T, Schulze, MB, Palli, D, Agnoli, C, Panico, S, Tumino, R, Ricceri, F, Verschuren, WMM, Engelfriet, P, Onland-Moret, C, Vermeulen, R, Nost, TH, Urbarova, I, Zamora-Ros, R, Rodriguez-Barranco, M, Amiano, P, Huerta, JM, Ardanaz, E, Melander, O, Ottoson, F, Vidman, L, Rentoft, M, Schmidt, JA, Travis, RC, Weiderpass, E, Johansson, M, Dossus, L, Jenab, M, Gunter, MJ, Bermejo, JL, Scherer, D, Salek, RM, Keski-Rahkonen, P, and Ferrari, P
- Abstract
Pooling metabolomics data across studies is often desirable to increase the statistical power of the analysis. However, this can raise methodological challenges as several preanalytical and analytical factors could introduce differences in measured concentrations and variability between datasets. Specifically, different studies may use variable sample types (e.g., serum versus plasma) collected, treated, and stored according to different protocols, and assayed in different laboratories using different instruments. To address these issues, a new pipeline was developed to normalize and pool metabolomics data through a set of sequential steps: (i) exclusions of the least informative observations and metabolites and removal of outliers; imputation of missing data; (ii) identification of the main sources of variability through principal component partial R-square (PC-PR2) analysis; (iii) application of linear mixed models to remove unwanted variability, including samples' originating study and batch, and preserve biological variations while accounting for potential differences in the residual variances across studies. This pipeline was applied to targeted metabolomics data acquired using Biocrates AbsoluteIDQ kits in eight case-control studies nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Comprehensive examination of metabolomics measurements indicated that the pipeline improved the comparability of data across the studies. Our pipeline can be adapted to normalize other molecular data, including biomarkers as well as proteomics data, and could be used for pooling molecular datasets, for example in international consortia, to limit biases introduced by inter-study variability. This versatility of the pipeline makes our work of potential interest to molecular epidemiologists.
- Published
- 2021
40. Extended multi bottom–up tree transducers: Composition and decomposition
- Author
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Engelfriet, Joost, Lilin, Eric, and Maletti, Andreas
- Published
- 2009
- Full Text
- View/download PDF
41. Gender differences in adult congenital heart disease
- Author
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Engelfriet, P. and Mulder, B. J. M.
- Published
- 2009
- Full Text
- View/download PDF
42. The time complexity of typechecking tree-walking tree transducers
- Author
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Engelfriet, Joost
- Published
- 2009
- Full Text
- View/download PDF
43. Referentiekader spreiding en beschikbaarheid ambulancezorg 2020
- Author
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Kommer, GJ, Engelfriet, P, Over, E, de Bruin-Kooistra, M, and Mohnen, SM
- Subjects
RIVM rapport 2020-0122 - Abstract
Het RIVM heeft berekend hoeveel ambulances er in Nederland in 2020 nodig zijn. Op werkdagen overdag zijn dat er 642, 20 meer dan vorig jaar is berekend. De belangrijkste verklaring voor de extra 20 ambulances is dat er meer standplaatsen nodig zijn. Er zijn meer standplaatsen nodig doordat de uitgangspunten van het rekenmodel zijn aangepast. Verder zijn door de bijgestelde uitgangspunten ook extra ambulances toebedeeld aan regio's waar de werkdruk erg hoog is. Een derde verklaring is dat er in 2019 meer ritten zijn gereden; het aantal ritten in het jaar ervoor wordt gebruikt in het rekenmodel. Het 'referentiekader spreiding en beschikbaarheid ambulancezorg' berekent het aantal ambulances waarmee de ambulancezorg in Nederland kan worden uitgevoerd. Dit model is gebaseerd op een aantal uitgangspunten voor de Nederlandse ambulancezorg. Voorbeelden zijn de tijd na een melding waarbinnen een ambulance ter plaatse moet zijn en de spreiding van de standplaatsen over het land. Het model is dit jaar aangepast om de 25 Regionale Ambulance Voorzieningen (RAV's) in Nederland vergelijkbare randvoorwaarden te geven voor de spreiding en capaciteit. Het ministerie van VWS, de Ambulancezorg Nederland (AZN) en Zorgverzekeraars Nederland (ZN) hebben de uitgangspunten bijgesteld. De minister voor Medische Zorg en Sport heeft het nieuwe referentiekader vastgesteld. De Nederlandse Zorgautoriteit (NZa) gebruikt de uitkomsten om te bepalen hoe de kosten van de ambulancezorg gedekt zullen worden.
- Published
- 2020
44. Doorontwikkeling referentiekader ambulancezorg 2020
- Author
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Kommer, GJ, Over, EAB, Engelfriet, P, Mohnen, SM, Mulder, M, and van den Berg, PL
- Subjects
RIVM rapport 2020-0009 - Abstract
Het 'referentiekader spreiding en beschikbaarheid ambulancezorg' (referentiekader) berekent hoeveel ambulances nodig zijn voor de 25 Regionale Ambulance Voorzieningen (RAV's) in Nederland. Het referentiekader is gebaseerd op een aantal uitgangspunten en randvoorwaarden. Er zijn een aantal knelpunten in de Nederlandse ambulancezorg. Dat heeft onder andere te maken met de spreiding van standplaatsen in de regio's en het aantal beschikbare ambulances. Het RIVM heeft daarom onderzocht hoe het referentiekader beter kan aansluiten bij de vraag naar ambulancezorg in de praktijk. Het heeft hiervoor een aantal varianten uitgewerkt met verschillen in het aantal standplaatsen en hun locaties. Dit onderzoek wordt de 'doorontwikkeling' van het referentiekader genoemd. Hierbij is nagegaan hoeveel inwoners bij deze varianten binnen 12 minuten rijtijd vanaf een standplaats kunnen worden bereikt, de 'dekking'. Ook is gekeken naar het aantal inwoners dat vanuit twee of meer standplaatsen kan worden bereikt, de 'dubbele dekking'. Verder is gekeken naar de werkdruk per RAV, oftewel het aantal spoedeisende inzetten per ambulance. Er zijn signalen dat de werkdruk in sommige RAV's hoog is. Berekend is hoeveel extra ambulances nodig zijn om de werkdruk te beperken. Tot slot is ingeschat hoeveel ambulances over twee jaar nodig zijn. Deze 'indexering' is gebaseerd op een analyse van het aantal ambulanceritten over de afgelopen vier jaar. Dit onderzoek is in opdracht van het ministerie van VWS uitgevoerd. In het bestuurlijk overleg tussen dit ministerie, zorgverzekeraars en de ambulancesector wordt besloten welke variant uit het onderzoek in het referentiekader-2020 zal worden gebruikt.
- Published
- 2020
45. Clique-Width for 4-Vertex Forbidden Subgraphs
- Author
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Brandstadt, Andreas, Engelfriet, Joost, Le, Hoang-Oanh, and Lozin, Vadim V.
- Published
- 2006
- Full Text
- View/download PDF
46. A new natural structural congruence in the pi-calculus with replication
- Author
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Engelfriet, Joost and Gelsema, Tjalling
- Published
- 2004
- Full Text
- View/download PDF
47. A comparison of pebble tree transducers with macro tree transducers
- Author
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Engelfriet, Joost and Maneth, Sebastian
- Published
- 2003
- Full Text
- View/download PDF
48. Linear, Branching Time and Joint Closure Semantics for Temporal Logic
- Author
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Engelfriet, Joeri and Treur, Jan
- Published
- 2002
- Full Text
- View/download PDF
49. Compositional Verification of Multi-Agent Systems in Temporal Multi-Epistemic Logic
- Author
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Engelfriet, Joeri, Jonker, Catholijn M., and Treur, Jan
- Published
- 2002
- Full Text
- View/download PDF
50. Lifetime medical costs of obesity: prevention no cure for increasing health expenditure.
- Author
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Pieter H M van Baal, Johan J Polder, G Ardine de Wit, Rudolf T Hoogenveen, Talitha L Feenstra, Hendriek C Boshuizen, Peter M Engelfriet, and Werner B F Brouwer
- Subjects
Medicine - Abstract
BackgroundObesity is a major cause of morbidity and mortality and is associated with high medical expenditures. It has been suggested that obesity prevention could result in cost savings. The objective of this study was to estimate the annual and lifetime medical costs attributable to obesity, to compare those to similar costs attributable to smoking, and to discuss the implications for prevention.Methods and findingsWith a simulation model, lifetime health-care costs were estimated for a cohort of obese people aged 20 y at baseline. To assess the impact of obesity, comparisons were made with similar cohorts of smokers and "healthy-living" persons (defined as nonsmokers with a body mass index between 18.5 and 25). Except for relative risk values, all input parameters of the simulation model were based on data from The Netherlands. In sensitivity analyses the effects of epidemiologic parameters and cost definitions were assessed. Until age 56 y, annual health expenditure was highest for obese people. At older ages, smokers incurred higher costs. Because of differences in life expectancy, however, lifetime health expenditure was highest among healthy-living people and lowest for smokers. Obese individuals held an intermediate position. Alternative values of epidemiologic parameters and cost definitions did not alter these conclusions.ConclusionsAlthough effective obesity prevention leads to a decrease in costs of obesity-related diseases, this decrease is offset by cost increases due to diseases unrelated to obesity in life-years gained. Obesity prevention may be an important and cost-effective way of improving public health, but it is not a cure for increasing health expenditures.
- Published
- 2008
- Full Text
- View/download PDF
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