Showing papers by "Utrecht University published in 2006"
University of New South Wales1, Hospital for Special Surgery2, Hokkaido University3, University of Utah4, University of Texas Health Science Center at San Antonio5, Utrecht University6, University of Milan7, Geneva College8, Sheba Medical Center9, University of Brescia10, National and Kapodistrian University of Athens11
TL;DR: This document appraise the existing evidence on clinical and laboratory features of APS addressed during the forum and proposes amendments to the Sapporo criteria, including definitions on features ofAPS that were not included in the updated criteria.
5,699 citations
TL;DR: In this article, the authors developed a short questionnaire to measure work engagement, a positive work-related state of fulfillment characterized by vigor, dedication, and absorption, which is defined as "a positive work related state of fulfilment".
Abstract: This article reports on the development of a short questionnaire to measure work engagement—a positive work-related state of fulfillment that is characterized by vigor, dedication, and absorption. ...
5,203 citations
TL;DR: A remarkable interdisciplinary effort has unraveled the WNT (Wingless and INT-1) signal transduction cascade over the last two decades, finding that Germline mutations in the Wnt pathway cause several hereditary diseases, and somatic mutations are associated with cancer of the intestine and a variety of other tissues.
5,042 citations
Utrecht University1, United States Environmental Protection Agency2, Health Canada3, Karolinska Institutet4, Houston Methodist Hospital5, Kaiserslautern University of Technology6, University of Tokyo7, World Health Organization8, National Institute for Health and Welfare9, Umeå University10, National Institutes of Health11, University of Wisconsin-Madison12
TL;DR: Concern was expressed about direct application of the TEF/total toxic equivalency (TEQ) approach to abiotic matrices, such as soil, sediment, etc., for direct application in human risk assessment as the present TEF scheme and TEQ methodology are primarily intended for estimating exposure and risks via oral ingestion.
3,284 citations
TL;DR: The evolutionary conservation of similar defense-related proteins in monocots and dicots, but also their divergent occurrence in other conditions, suggest that these proteins serve essential functions in plant life, whether in defense or not.
Abstract: Inducible defense-related proteins have been described in many plant species upon infection with oomycetes, fungi, bacteria, or viruses, or insect attack. Several types of proteins are common and have been classified into 17 families of pathogenesis-related proteins (PRs). Others have so far been found to occur more specifically in some plant species. Most PRs and related proteins are induced through the action of the signaling compounds salicylic acid, jasmonic acid, or ethylene, and possess antimicrobial activities in vitro through hydrolytic activities on cell walls, contact toxicity, and perhaps an involvement in defense signaling. However, when expressed in transgenic plants, they reduce only a limited number of diseases, depending on the nature of the protein, plant species, and pathogen involved. As exemplified by the PR-1 proteins in Arabidopsis and rice, many homologous proteins belonging to the same family are regulated developmentally and may serve different functions in specific organs or tissues. Several defense-related proteins are induced during senescence, wounding or cold stress, and some possess antifreeze activity. Many defense-related proteins are present constitutively in floral tissues and a substantial number of PR-like proteins in pollen, fruits, and vegetables can provoke allergy in humans. The evolutionary conservation of similar defense-related proteins in monocots and dicots, but also their divergent occurrence in other conditions, suggest that these proteins serve essential functions in plant life, whether in defense or not.
2,747 citations
TL;DR: In this paper, the authors proposed that there are two parallel processes involved in work-related well-being among teachers, namely an energetical process (i.e., job demands→ burnout/engagement→ ill health) and a motivational process.
2,445 citations
TL;DR: In this paper, the authors show that both single and multiple imputations of missing data almost always result in biased estimates, and they also explain and illustrate why two commonly used methods to handle missing data, i.e., overall mean imputation and the missing-indicator method, almost always yield biased estimates.
2,104 citations
TL;DR: Current evidence suggests a direct link between miRNAs and disease, and miRNA expression signatures are associated with various types of cancer, and the gain and loss of miRNA target sites appears to be causal to some genetic disorders.
1,999 citations
TL;DR: The findings of mechanistic studies suggest that vascular disease and alterations in glucose, insulin, and amyloid metabolism underlie the pathophysiology of dementia, but which of these mechanisms are clinically relevant is unclear.
Abstract: The relation between diabetes and major types of dementia is controversial. This systematic review examines the incidence of dementia in people with diabetes mellitus. We identified 14 eligible longitudinal population-based studies of variable methodological quality. The incidence of "any dementia" was higher in individuals with diabetes than in those without diabetes in seven of ten studies reporting this aggregate outcome. This high risk included both Alzheimer's disease and vascular dementia (eight of 13 studies and six of nine studies respectively). Detailed data on modulating and mediating effects of glycaemic control, microvascular complications, and comorbidity (eg, hypertension and stroke) were generally absent. The findings of mechanistic studies suggest that vascular disease and alterations in glucose, insulin, and amyloid metabolism underlie the pathophysiology, but which of these mechanisms are clinically relevant is unclear. Further high quality studies need to be initiated, with objective diabetes assessment, together with reliable methods to establish the contribution of vascular disease and other comorbidity to dementia.
1,836 citations
TL;DR: This study shows that Muc2 deficiency leads to inflammation of the colon and contributes to the onset and perpetuation of experimental colitis.
1,391 citations
TL;DR: The current knowledge of priming in various induced-resistance phenomena in plants is summarized.
Abstract: Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called "priming." The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of priming in various induced-resistance phenomena in plants.
TL;DR: X-ray absorption spectroscopy revealed that cobalt was metallic, even for small particle sizes, after the in situ reduction treatment, which is a prerequisite for catalytic operation and is difficult to achieve using traditional oxidic supports.
Abstract: The influence of cobalt particle size in the range of 2.6-27 nm on the performance in Fischer-Tropsch synthesis has been investigated for the first time using well-defined catalysts based on an inert carbon nanofibers support material. X-ray absorption spectroscopy revealed that cobalt was metallic, even for small particle sizes, after the in situ reduction treatment, which is a prerequisite for catalytic operation and is difficult to achieve using traditional oxidic supports. The turnover frequency (TOF) for CO hydrogenation was independent of cobalt particle size for catalysts with sizes larger than 6 nm (1 bar) or 8 nm (35 bar), while both the selectivity and the activity changed for catalysts with smaller particles. At 35 bar, the TOF decreased from 23 x 10(-3) to 1.4 x 10(-3) s(-1), while the C5+ selectivity decreased from 85 to 51 wt % when the cobalt particle size was reduced from 16 to 2.6 nm. This demonstrates that the minimal required cobalt particle size for Fischer-Tropsch catalysis is larger (6-8 nm) than can be explained by classical structure sensitivity. Other explanations raised in the literature, such as formation of CoO or Co carbide species on small particles during catalytic testing, were not substantiated by experimental evidence from X-ray absorption spectroscopy. Interestingly, we found with EXAFS a decrease of the cobalt coordination number under reaction conditions, which points to reconstruction of the cobalt particles. It is argued that the cobalt particle size effects can be attributed to nonclassical structure sensitivity in combination with CO-induced surface reconstruction. The profound influences of particle size may be important for the design of new Fischer-Tropsch catalysts.
TL;DR: This special issue of Technology Analysis and Straights focuses on expectations in science and technology innovation and the role that expectations play in innovation.
Abstract: In recent years a growing number of social science studies have pointed out the significance of expectations in science and technology innovation. This special issue of Technology Analysis and Stra...
TL;DR: In this article, an improved Hamiltonian constraint operator is introduced in loop quantum cosmology for the isotropic model with a massless scalar field and the big bang is replaced by a quantum bounce.
Abstract: An improved Hamiltonian constraint operator is introduced in loop quantum cosmology. Quantum dynamics of the spatially flat, isotropic model with a massless scalar field is then studied in detail using analytical and numerical methods. The scalar field continues to serve as ''emergent time'', the big bang is again replaced by a quantum bounce, and quantum evolution remains deterministic across the deep Planck regime. However, while with the Hamiltonian constraint used so far in loop quantum cosmology the quantum bounce can occur even at low matter densities, with the new Hamiltonian constraint it occurs only at a Planck-scale density. Thus, the new quantum dynamics retains the attractive features of current evolutions in loop quantum cosmology but, at the same time, cures their main weakness.
Max Planck Society1, University of Marburg2, Broad Institute3, Trent University4, University of Toronto5, California State University, Long Beach6, University of British Columbia7, University of Georgia8, University of Louisville9, Utrecht University10, Saint Joseph's University11, Spanish National Research Council12, Cornell University13, CINVESTAV14, University of Kentucky15, Duke University16, University of Valencia17, Saint Louis University18, Bayer19, Exelixis20, Technische Universität München21
TL;DR: The discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi.
Abstract: Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a member of this economically important group of biotrophic fungi. The 20.5-million-base U. maydis genome assembly contains 6,902 predicted protein-encoding genes and lacks pathogenicity signatures found in the genomes of aggressive pathogenic fungi, for example a battery of cell-wall-degrading enzymes. However, we detected unexpected genomic features responsible for the pathogenicity of this organism. Specifically, we found 12 clusters of genes encoding small secreted proteins with unknown function. A significant fraction of these genes exists in small gene families. Expression analysis showed that most of the genes contained in these clusters are regulated together and induced in infected tissue. Deletion of individual clusters altered the virulence of U. maydis in five cases, ranging from a complete lack of symptoms to hypervirulence. Despite years of research into the mechanism of pathogenicity in U. maydis, no 'true' virulence factors had been previously identified. Thus, the discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi. Genomic analysis is, similarly, likely to open up new avenues for the discovery of virulence determinants in other pathogens.
TL;DR: In this paper, the authors review the problem of attempting to quantify landslide risk over larger areas, discussing a number of difficulties related to the generation of landslide inventory maps including information on date, type and volume of the landslide, the determination of its spatial and temporal probability, the modelling of runout and the assessment of landslide vulnerability.
Abstract: The quantification of risk has gained importance in many disciplines, including landslide studies. The literature on landslide risk assessment illustrates the developments which have taken place in the last decade and that quantitative risk assessment is feasible for geotechnical engineering on a site investigation scale and the evaluation of linear features (e.g., pipelines, roads). However, the generation of quantitative risk zonation maps for regulatory and development planning by local authorities still seems a step too far, especially at medium scales (1:10,000–1:50,000). This paper reviews the problem of attempting to quantify landslide risk over larger areas, discussing a number of difficulties related to the generation of landslide inventory maps including information on date, type and volume of the landslide, the determination of its spatial and temporal probability, the modelling of runout and the assessment of landslide vulnerability. An overview of recent developments in the different approaches to landslide hazard and risk zonation at medium scales is given. The paper concludes with a number of new advances and challenges for the future, such as the use of very detailed topographic data, the generation of event-based landslide inventory maps, the use of these maps in spatial-temporal probabilistic modelling and the use of land use and climatic change scenarios in deterministic modelling.
TL;DR: A new version of the human ventricular cell model is developed, which is based on recent experimental measurements of human APD restitution and includes a more extensive description of intracellular calcium dynamics, which concludes that steepAPD restitution-mediated instability is a potential mechanism for VF in the human heart.
Abstract: Ventricular fibrillation (VF) is one of the main causes of death in the Western world. According to one hypothesis, the chaotic excitation dynamics during VF are the result of dynamical instabilities in action potential duration (APD) the occurrence of which requires that the slope of the APD restitution curve exceeds 1. Other factors such as electrotonic coupling and cardiac memory also determine whether these instabilities can develop. In this paper we study the conditions for alternans and spiral breakup in human cardiac tissue. Therefore, we develop a new version of our human ventricular cell model, which is based on recent experimental measurements of human APD restitution and includes a more extensive description of intracellular calcium dynamics. We apply this model to study the conditions for electrical instability in single cells, for reentrant waves in a ring of cells, and for reentry in two-dimensional sheets of ventricular tissue. We show that an important determinant for the onset of instability is the recovery dynamics of the fast sodium current. Slower sodium current recovery leads to longer periods of spiral wave rotation and more gradual conduction velocity restitution, both of which suppress restitution-mediated instability. As a result, maximum restitution slopes considerably exceeding 1 (up to 1.5) may be necessary for electrical instability to occur. Although slopes necessary for the onset of instabilities found in our study exceed 1, they are within the range of experimentally measured slopes. Therefore, we conclude that steep APD restitution-mediated instability is a potential mechanism for VF in the human heart.
TL;DR: In this paper, the authors discuss the commonalities and differences between the three approaches in terms of soft-heoretical content and research methodologies, and argue that evolutionary economic geography can be seen as a bridge between evolutionary theory and institutional and evolutionary theory.
Abstract: Thepaperexplainsthecommonalitiesanddifferencesbetweenneoclassical, institutional and evolutionary approaches that have been influential in economic geography during the last couple of decades. By separating the three approaches in termsoftheoretical content and researchmethodology, wecanappreciateboththecommonalitiesanddifferencesbetweenthethree approaches. It is also apparent that innovative theorizing currently occurs at the interface between neoclassical and evolutionary theory (especially in modelling) and at the interface between institutional and evolutionary theory (especially in ‘appreciative theorizing’). Taken together, we argue thatEvolutionaryEconomicGeographyisanemergingparadigmineconomic geography, yet does so without isolating itself from developments in other theoretical approaches.
TL;DR: In this article, the authors investigated the performance of conditional model specification for multivariate imputation in incomplete multivariate data by means of simulation and showed that the results were produced using only five Gibbs iterations starting from a simple draw from observed marginal distributions.
Abstract: The use of the Gibbs sampler with fully conditionally specified models, where the distribution of each variable given the other variables is the starting point, has become a popular method to create imputations in incomplete multivariate data. The theoretical weakness of this approach is that the specified conditional densities can be incompatible, and therefore the stationary distribution to which the Gibbs sampler attempts to converge may not exist. This study investigates practical consequences of this problem by means of simulation. Missing data are created under four different missing data mechanisms. Attention is given to the statistical behavior under compatible and incompatible models. The results indicate that multiple imputation produces essentially unbiased estimates with appropriate coverage in the simple cases investigated, even for the incompatible models. Of particular interest is that these results were produced using only five Gibbs iterations starting from a simple draw from observed marginal distributions. It thus appears that, despite the theoretical weaknesses, the actual performance of conditional model specification for multivariate imputation can be quite good, and therefore deserves further study. © 2006 Taylor & Francis.
Max Planck Society1, Leibniz Institute for Neurobiology2, Monash University, Clayton campus3, University of Montpellier4, Open University5, Thermo Electron6, German Criminal Police Office7, University of Würzburg8, University of Victoria9, University of Gothenburg10, Royal Canadian Mounted Police11, University of Tasmania12, University of Houston13, University of Mainz14, Paul Scherrer Institute15, Carnegie Institution for Science16, University of Kiel17, University of Greifswald18, University of Edinburgh19, Oregon State University20, Heidelberg University21, Utrecht University22, National Institute of Polar Research23, University of Utah24, Freiberg University of Mining and Technology25, United States Geological Survey26, Chinese Academy of Sciences27, University of Pavia28, University of Tübingen29, University of Lausanne30, Los Alamos National Laboratory31, University of Melbourne32
TL;DR: In this paper, the authors present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G and ATHO-G.
Abstract: We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented.
TL;DR: In this paper, the authors examined the latter association by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic, concluding that depression may occur as a consequence of having diabetes, but may also be a risk factor for the onset of type 2 diabetes.
Abstract: Aims/hypothesis
Evidence strongly suggests that depression and type 2 diabetes are associated, but the direction of the association is still unclear. Depression may occur as a consequence of having diabetes, but may also be a risk factor for the onset of type 2 diabetes. This study examined the latter association by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.
TL;DR: In this article, the authors investigated whether work engagement (measured by the Utrecht Work Engagement Scale; UWES) could be empirically separated from job involvement and organizational commitment.
Abstract: The present study investigates whether work engagement (measured by the Utrecht Work Engagement Scale; UWES) could be empirically separated from job involvement and organizational commitment. In addition, psychometric properties of the Swedish UWES were investigated. Discriminant validity of the UWES was tested through inspection of latent intercorrelations between the constructs, confirmatory factor analyses, and patterns of correlations with other constructs (health complaints, job and personal factors, and turnover intention) in a sample of Information Communication Technology consultants (N = 186). Conclusion: Work engagement, job involvement, and organizational commitment are empirically distinct constructs and, thus, reflect different aspects of work attachment. The internal consistency of the Swedish UWES was satisfactory, but the dimensionality was somewhat unclear.
TL;DR: Interfering with sequence-embedded polarity signals directly demonstrates that PIN polarity is a primary factor in determining the direction of auxin flow in meristematic tissues.
Abstract: Polar flow of the phytohormone auxin requires plasma membrane-associated PIN proteins and underlies multiple developmental processes in plants. Here we address the importance of the polarity of subcellular PIN localization for the directionality of auxin transport in Arabidopsis thaliana. Expression of different PINs in the root epidermis revealed the importance of PIN polar positions for directional auxin flow and root gravitropic growth. Interfering with sequence-embedded polarity signals directly demonstrates that PIN polarity is a primary factor in determining the direction of auxin flow in meristematic tissues. This finding provides a crucial piece in the puzzle of how auxin flow can be redirected via rapid changes in PIN polarity.
TL;DR: In this article, the core burnout and engagement dimensions can be seen as opposites of each other along two distinct bipolar dimensions dubbed energy and identification, and the results obtained by means of the nonparametric Mokken scaling method in three different samples (Ns = 477, 507, and 381) supported their proposal.
TL;DR: For all types of missing values, imputation of missing predictor values using the outcome is preferred over imputation without outcome and is no self-fulfilling prophecy.
TL;DR: In this article, the authors present an overview of state-of-the-art naphtha cracking technologies and show that up to 20% savings on the current average process energy use are possible.
Broad Institute1, University of Oxford2, Wellcome Trust Sanger Institute3, Wellcome Trust Centre for Human Genetics4, Utrecht University5, Science Applications International Corporation6, Illumina7, Duke University8, Brigham and Women's Hospital9, University of Cambridge10, Harvard University11, Imperial College London12, Université de Montréal13, Montreal Heart Institute14
TL;DR: The analysis provides informative tag SNPs that capture much of the common variation in the MHC region and that could be used in disease association studies, and it provides new insight into the evolutionary dynamics and ancestral origins of the HLA loci and their haplotypes.
Abstract: The proteins encoded by the classical HLA class I and class II genes in the major histocompatibility complex (MHC) are highly polymorphic and are essential in self versus non-self immune recognition. HLA variation is a crucial determinant of transplant rejection and susceptibility to a large number of infectious and autoimmune diseases. Yet identification of causal variants is problematic owing to linkage disequilibrium that extends across multiple HLA and non-HLA genes in the MHC. We therefore set out to characterize the linkage disequilibrium patterns between the highly polymorphic HLA genes and background variation by typing the classical HLA genes and >7,500 common SNPs and deletion-insertion polymorphisms across four population samples. The analysis provides informative tag SNPs that capture much of the common variation in the MHC region and that could be used in disease association studies, and it provides new insight into the evolutionary dynamics and ancestral origins of the HLA loci and their haplotypes.
TL;DR: The benefits of priming-mediated resistance outweigh the costs in environments in which disease occurs, and priming involves less fitness costs than induced direct defense.
Abstract: Induced resistance protects plants against a wide spectrum of diseases; however, it can also entail costs due to the allocation of resources or toxicity of defensive products. The cellular defense responses involved in induced resistance are either activated directly or primed for augmented expression upon pathogen attack. Priming for defense may combine the advantages of enhanced disease protection and low costs. In this study, we have compared the costs and benefits of priming to those of induced direct defense in Arabidopsis. In the absence of pathogen infection, chemical priming by low doses of beta-aminobutyric acid caused minor reductions in relative growth rate and had no effect on seed production, whereas induction of direct defense by high doses of beta-aminobutyric acid or benzothiadiazole strongly affected both fitness parameters. These costs were defense-related, because the salicylic acid-insensitive defense mutant npr1-1 remained unaffected by these treatments. Furthermore, the constitutive priming mutant edr1-1 displayed only slightly lower levels of fitness than wild-type plants and performed considerably better than the constitutively activated defense mutant cpr1-1. Hence, priming involves less fitness costs than induced direct defense. Upon infection by Pseudomonas syringae or Hyaloperonospora parasitica, priming conferred levels of disease protection that almost equaled the protection in benzothiadiazole-treated wild-type plants and cpr1 plants. Under these conditions, primed plants displayed significantly higher levels of fitness than noninduced plants and plants expressing chemically or cpr1-induced direct defense. Collectively, our results indicate that the benefits of priming-mediated resistance outweigh the costs in environments in which disease occurs.
TL;DR: In a large series of 130 patients, the optimal approach to define the infarct and the penumbra is a combined approach using 2 PCT parameters: relative MTT and absolute CBV, with dedicated thresholds.
Abstract: Background and Purpose— Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak) in a large series of acute stroke patients, to determine which (combination of) parameters most accurately predicts infarct and penumbra. Methods— One hundred and thirty patients with symptoms suggesting hemispheric stroke ≤12 hours from onset were enrolled in a prospective multicenter trial. They all underwent admission PCT and follow-up diffusion-weighted imaging/fluid-attenuated inversion recovery (DWI/FLAIR); 25 patients also underwent admission DWI/FLAIR. PCT maps were assessed for absolute and relative reduced CBV, reduced cerebral blood flow, increased MTT, and increased time-to-peak. Receiver-operating characteristic curve analysis was performe...
TL;DR: The English-language dictionary defines wrinkles as small furrows, ridges, or creases on a normally smooth surface, caused by crumpling, folding, or shrinking as mentioned in this paper.
Abstract: The English-language dictionary defines wrinkles as “small furrows, ridges, or creases on a normally smooth surface, caused by crumpling, folding, or shrinking”. In this paper we review the scientific aspects of wrinkling and the related phenomenon of buckling. Specifically, we discuss how and why wrinkles/buckles form in various materials. We also describe several examples from everyday life, which demonstrate that wrinkling or buckling is indeed a commonplace phenomenon that spans a multitude of length scales. We will emphasize that wrinkling is not always a frustrating feature (e.g., wrinkles in human skin), as it can help to assemble new structures, understand important physical phenomena, and even assist in characterizing chief material properties.