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We present the results of the automated post-processing of Mueller microscopy images of skin tissue models with a new fast version of the algorithm of density-based spatial clustering of applications with noise (FastDBSCAN) and discuss the advantages of its implementation for digital histology of tissue. We demonstrate that using the FastDBSCAN algorithm, one can produce the diagnostic segmentation of high resolution images of tissue by several orders of magnitude faster and with high accuracy ( > 97 % ) compared to the original version of the algorithm.

Assisted flipping of a slant mode I dominated tearing crack, where the crack tip flipping mechanism is made to engage by imposing a slight mode III, has recently been studied in Felter and Nielsen (2017) [Assisted crack tip flipping under Mode I thin sheet tearing, Europ. J. Mech. A/Solids, 64;2017:58–68]. In the previous study, the Gurson–Tvergaard–Needleman model was used in its original form to limit the model parameter space and facilitate a search for a set of parameter that allows flipping of the slant crack face to occur. It is well known that the adopted version of the Gurson model can predict the shear bands that travel in front of a mode I tearing crack and these are essential features to slant crack propagation — let alone the experimentally observed crack tip flipping phenomenon. In fact, assisted crack tip flipping was achieved with this numerical model set-up, but only within a very narrow parameter window. The present work adopts a phenomenological shear extended Gurson model that allows for a study of the J3 dependency in ductile fracture at engineering scale in an attempt to widen this parameter window. By running series of large-scale computations, where a ductile tearing crack propagates multiple plate thicknesses, the authors can demonstrate tearing modes for various combinations of strain hardening, initial void volume fraction, and shear parameter. The shear damage contribution is found to shift the engagement of the crack tip flipping mechanism toward lower values of the initial void volume fraction for all levels of strain hardening considered.

Ductile plate tearing, where the crack propagates multiple plate thicknesses, is targeted by the micro-mechanics based Gurson-Tvergaard-Needleman (GTN) model. The focus is on extracting detailed information on the fracture process that governs ductile crack initiation from a blunt pre-crack until the crack reaches steady-state propagation in order to enhance accuracy of the traditionally used cohesive zone traction-separation relations. The aim is to facilitate an accurate representation of the tearing process within the cohesive zone modeling framework as such simplistic models are largely exploited by engineers worldwide. Unfortunately, accuracy in the representation of crack propagation is often sacrificed for computation speed, but the present work allows correlating the cohesive zone modeling to a much more accurate, though computational expensive, micro-mechanics based (full 3D) model response. In the modeling of large-scale plate tearing, shell elements are typically employed to represent the engineering scale of the structure while the cohesive zone represents the micro-scale in terms of crack initiation and growth process. Thus, the cohesive zone essentially has to take over at the onset of the first localization (thinning far ahead of the crack tip). Calibration of the cohesive zone parameters has earlier been made in accordance with experimental observations such that the overall response of the system is well reproduced. But, the present work takes the calibration of the cohesive zone one step further and exploits details from a large-scale GTN model calculation. The goal is to match the response from the GTN model with the much less computation demanding cohesive zone modeling approach by incorporating knowledge of the loading history for individual cross-sections, in front of the pre-crack, through which the tearing crack propagates. The full 3D micro-mechanics based model set-up allows tracking of key parameters, such as peak traction and tearing energy, which goes into the cohesive traction-separation relation. The dependency on distance from the crack initiation site of the cohesive zone parameters is determined - from crack initiation to steady-state propagation - and followed up by a discussion on how to construct a traction-separation relation for ductile plate tearing.

Histological analysis with white light microscopy of few micron-thick sections of tissue remains a gold standard for tissue biopsy. However, this approach requires a cumbersome multi-step preparation of the sample and relies heavily on the skills of a pathologist. In general, any tissue pathology (e.g. inflammation, fibrosis, cancer) affects the constituents of tissue and changes both optical properties of cells and extracellular matrix. We suggest using the images of transmittance, retardance and depolarization of unstained tissue samples, acquired with the Mueller microscopy, as an input data for automated diagnostic image segmentation. The potential of combining polarimetric data with non-linear microscopy data, such as Second Harmonic Generation (SHG) and Two Photon Emission Fluorescence (TPEF), is also explored for the diagnostic of tissue specific components (e. g. collagen, elastin). The unstained histological cuts of full thickness skin equivalents and cervical tissue of mouse were used for multi-modal microscopy imaging. First, the statistical approach was tested for a segmentation of the images of artificial skin using the images of retardance, depolarization, and transmitted unpolarized intensity. The algorithm of density-based spatial clustering of applications with noise (DBSCAN) clearly discriminates the regions of dermal and epidermal layers of skin cuts. The same approach was tested on the extended set of data including polarimetric, SHG and TPEF images of the histological cuts of mouse uterine cervix. The typical circumferential arrangement of collagen fibers around the cervical os as well as elastin lining of the internal cavities was observed on the segmented images. Merging polarimetric data with SHG data makes clear the appearance of fine structures in the cervical os region. The work is ongoing on testing different data post-processing algorithms for increasing both contrast and accuracy of tissue image segmentation, thus, paving the way for the digital histology for tissue diagnostic.

Tissue-based diagnostic relies on histological analysis of tissue cuts by a pathologist who links data derived from microscopy image content to a specific disease. We explored the potential of Mueller microscopy combined with density-based spatial clustering algorithm for applications with noise for the automated analysis of tissue histological cuts. Mueller microscopic images of unstained artificial human skin histological cuts were analyzed by applying differential Mueller matrix decomposition. Scalar retardance, depolarization and total transmitted intensity images were used for the automated segmentation of microscopic images. An algorithm of polarimetric data post-processing which mitigates the impact of tissue thickness fluctuations was suggested.

Significance : Definitive diagnostics of many diseases is based on the histological analysis of thin tissue cuts with optical white light microscopy. Extra information on tissue structural properties obtained with polarized light would help the pathologist to improve the accuracy of his diagnosis. Aim: We report on using Mueller matrix microscopy data, logarithmic decomposition, and polarized Monte Carlo (MC) modeling for qualitative and quantitative analysis of thin tissue cuts to extract the information on tissue microstructure that is not available with a conventional white light microscopy. Approach: Unstained cuts of human skin equivalents were measured with a custom-built liquid-crystal-based Mueller microscope in transmission configuration. To interpret experimental data, we performed the simulations with a polarized MC algorithm for scattering anisotropic media. Several optical models of tissue (spherical scatterers within birefringent host medium, and combination of spherical and cylindrical scatterers within either isotropic or birefringent host medium) were tested. Results: A set of rotation invariants for the logarithmic decomposition of a Mueller matrix was derived to rule out the impact of sample orientation. These invariants were calculated for both simulated and measured Mueller matrices of the dermal layer of skin equivalents. We demonstrated that only the simulations with a model combining both spherical and cylindrical scatterers within birefringent host medium reproduced the experimental trends in optical properties of the dermal layer (linear retardance, linear dichroism, and anisotropic linear depolarization) with layer thickness. Conclusions: Our studies prove that Mueller polarimetry provides relevant information not only on a size of dominant scatterers (e.g., cell nuclei versus subwavelength organelles) but also on its shape (e.g., cells versus collagen fibers). The latter is directly related to the state of extracellular collagen matrix, which is often affected by early pathology. Hence, using polarimetric data can help to increase the accuracy of diagnosis.

Crack tip flipping, where the fracture surface alternates from side to side in roughly 45° shear bands, seems to be an overlooked propagation mode in Mode I thin sheet tearing. In fact, observations of crack tip flipping is rarely found in the literature. Unlike the already established modes such as slanting, cup-cone (rooftop), or cup-cup (bathtub) the flipping crack never settles in a steady-state as the near tip stress/strain field continuously change when the flip successively initiates and develops shear-lips. A recent experimental investigation has revealed new insight by exploiting 3D X-ray tomography scanning of a developing crack tip flip. But, it remains to be understood what makes the crack flip systematically, what sets the flipping frequency, and under which material conditions this mode occurs. The present study aims at investigating the idea that a slight out-of-plane action (Mode III type loading) on the tip of a slant Mode I crack can provoke it to flip to the opposite side. Both experiments and micro-mechanics based modeling support this hypothesis.

Mueller transmission microscopy has been used for both theoretical and experimental studies of anisotropic scattering biological tissue. In our prior study, the linear dependence of retardance and quadratic dependence of depolarization on thickness was demonstrated for a dermal layer of skin model. During the primary analysis of polarimetric images of histological cuts both epidermal and dermal layers were delineated manually in order to calculate the spatially averaged values of retardance and depolarization parameters. Consequently, these average values contained the contribution of outliers (noise, not correctly identified pixels, etc.) which produces large standard deviation and biased mean values of the parameters mentioned above. For preventing the errors, the normalized maps of optical properties were calculated pixel-wise taking into account local optical density (e. i. logarithm of M11 element of Mueller matrix at each image pixel) to compensate varying tissue thickness across the cut area. Furthermore, the DBSCAN (Density-based spatial clustering of applications with noise) algorithm was applied for segmentation of microscopic images using the normalized values of retardance, depolarization, and intensity. From the results of image segmentation, we could discriminate the regions of dermal and epidermal layers in Muller microscopic images of skin cuts more accurately and obtain more reliable values of tissue’s optical properties.

In this article, I argue that Marx’s philosophy does not commit us to Worrell and Krier’s claim that a post-capitalist society will be a social formation in which all social relations appear unmediated to their agents. Quite the opposite is true: given his Hegelian background, which Marx never gives up, social relations are in principle to be mediated by the results of human productive acts, and although a socialist society no longer is mediated by capital, it still cannot be thought without a legal, ethical, and political form of these relations. Those meditations (which Worrell and Krier do not separate clearly from social-economic aspects) will be universal. Accordingly, the authors’ claim that Marx is opposed to the concept of the universal is baseless. In addition, I demonstrate that Worrell and Krier’s interpretation of Marx’s concept of alienation as a romantic concept is misguided and, instead, that we would do well to focus on the concept of private property. Finally, I show that they do not properly grasp Marx’s concepts of democracy and communism.

In the last decades significant regulatory attempts were made to replace, refine and reduce animal testing to assess the risk of consumer products for the human eye. As the original in vivo Draize eye test has been criticized for limited predictivity, costs and ethical issues, several animal-free test methods have been developed to categorize substances according to the global harmonized system (GHS) for eye irritation.This review summarizes the progress of alternative test methods for the assessment of eye irritation. Based on the corneal anatomy and the current knowledge of the mechanisms causing eye irritation, different ex vivo and in vitro methods will be presented and discussed in regard of possible limitations and their status of regulatory acceptance. In addition to established in vitro models, this review will also highlight emerging, full thickness cornea models that might be applicable to predict all GHS categories.

The combined approach including experiments (Mueller polarimetry) and theory (differential Mueller matrix formalism) for the studies of anisotropic scattering media was tested on the model system of human skin. Custom-build Mueller polarimetric microscope was used for the studies of histological cuts of full-thickness skin equivalents generated from epidermal keratinocytes forming a multilayered epidermis on top of collagen I hydrogel with dermal fibroblasts. The sets of fixed unstained tissue cuts of different thicknesses (5μm - 30μm) were measured in transmission configuration. The values of polarimetric (dichroism and retardance) and depolarization parameters were calculated by applying pixel-wise the logarithmic decomposition of Mueller matrices. The parabolic dependence of depolarization parameters and linear dependence of polarimetric parameters on thickness, as predicted by theory, was confirmed by measurements. It proves that phenomenological modeling of complex anisotropic scattering medium (e.g., biological tissue) may effectively disentangle the polarimetric and depolarizing properties of the system understudies and may be used for analysis and diagnostics of tissue.

Because of a rising use of in vitro models as an alternative to animal models, the precise assessment of tissue-specific parameters of such in vitro test systems has become a critical part of ensuring predictive results. Impedance spectroscopy as a noninvasive method serves as a reliable and efficient tool for quality control because it only minimally interferes with the system during investigation. In this study, we present a refined impedance measurement system using nanostructured titanium nitride (TiN) electrodes. This advanced material was used to investigate tissue maturation and changes in the barrier integrity of an intestinal Transwell-based in vitro model. The reduction of noise facilitated a more detailed data extraction and biological interpretation. Compared to standard stainless steel electrodes, at a typical measurement frequency of 12.5 Hz, the maximum electrode impact on the signal could be reduced from over 75% to less than 5%. This allowed the accurate determination of transepithelial electrical resistance values from Caco-2 in vitro tissue models without a further mathematical analysis based on a computer simulation. The novel design of a 3D-printed measurement attachment equipped with nanostructured TiN electrodes was used to continuously monitor the barrier integrity of the Caco-2 cells during a permeability assay. Moreover, because of low process temperatures, the TiN coatings for enhanced impedance measurement sensitivity could also be deposited onto several other materials, e.g., commercially available cell culture equipment such as standard disposable multiwell plate dishes. In conclusion, we developed a novel method to improve the electrode properties for impedance spectroscopy, which can be easily implemented into standardized end-point measurement to qualify a variety of in vitro test systems.

Analysing international forestry congresses and (by way of example) the exploration of Northern Norway and Finland in the late nineteenth and early twentieth centuries, the article examines the changing conditions of natural resource management in the Baltic and North Sea regions. From the mid-nineteenth century onward, the overall increasing consumption of wood and the advancing timber frontier in Northern Europe questioned the Western European perception of Northern Europe as possessing inexhaustible woodlands. At the same time, the expanding railway network in Central Europe overran traditional (local) concepts of sustainable forest management. Since 1873, at international congresses, experts have debated the consequences of these spatial changes for the future prospects of forestry. On the one hand, pessimistic voices warned about a coming worldwide shortage of timber. On the other hand, optimistic statements saw the railway as a solution, as it allowed for timber to be transported wherever rails were laid. In the countries of the Baltic and North Sea regions, state authorities, as well as forestry academies, took up the debate and tried to improve their knowledge of accessible forest resources, for instance by sending expeditions to the woodlands of Northern Europe. The expanding railway network as well as the accumulation and cross border circulation of new knowledge about forest resources led to an ongoing process of rescaling sustainability: forestry experts continuously tried to keep in step with the changing spatial conditions of forestry planning (timber frontier, railway network) and at the same time fostered these changes. Experts suggested and advocated either spatial limits – for instance laws for regional forest protection – or further spatial extensions – such as new railway lines or channels – in order to shape the spatial framework of future forest management.

Full-thickness skin equivalents are gathering increased interest as skin grafts for the treatment of large skin defects or chronic wounds or as nonanimal test platforms. However, their fibroblast-mediated contraction and poor mechanical stability lead to disadvantages toward their reproducibility and applicability in vitro and in vivo. To overcome these pitfalls, we aimed to chemically cross-link the dermal layer of a full-thickness skin model composed of a collagen type I hydrogel. Using a noncytotoxic four-arm succinimidyl glutarate polyethylene glycol (PEG-SG), cross-linking could be achieved in cell seeded collagen hydrogels. A concentration of 0.5 mg of PEG-SG/mg of collagen led to a viability comparable to non-cross-linked collagen hydrogels and no increased release of intracellular lactate dehydrogenase. Cross-linked collagen hydrogels were more mechanically stable and less prone to enzymatic degradation via collagenase when compared with non-cross-linked collagen hydrogels. Remarkably, during 21 days, cross-linked collagen hydrogels maintain their initial surface area, whereas standard dermal models contracted up to 50%. Finally, full-thickness skin equivalents were generated by seeding human epidermal keratinocytes on the surface of the equivalents and culturing these equivalents at an air-liquid interface. Immunohistochemical stainings of the cross-linked model revealed well-defined epidermal layers including an intact stratum corneum and a dermal part with homogeneously distributed human dermal fibroblasts. These results indicate that cross-linking of collagen with PEG-SG reduces contraction of collagen hydrogels and thus increases the applicability of these models as an additional tool for efficacy and safety assessment or a new generation of skin grafts.

In vitro test systems gain increasing importance in preclinical studies to increase the predictivity and reduce animal testing. Of special interest herein are barrier tissues that guard into the human body. These barriers are formed by highly specialized tissues such as the skin, the airways, and the intestine. However, to recapitulate these tissues, researchers are currently restricted by a lack of suitable supporting scaffolds. In this study, we present biological scaffolds based on decellularized porcine gut segments that offer a natural environment for cell growth and differentiation. Employing these scaffolds, human barrier models of the skin, the airways, and the intestine that mimic the natural histological architecture of the respective tissue are generated. These models show tissue specific barrier properties, such as the stratification of the skin, the mucociliary phenotype of the airways, and polarization of the intestinal epithelium. To investigate the transport characteristics of the intestinal test system, we incubated the tissue models with fluorescein (Papp 7 x 106 cm/s), and rhodamin123 (ratio 2.45). The here presented biological scaffolds facilitate the in vitro generation of human barrier models that might represent useful tools for drug delivery studies.

As one of very few authors in the Anglo-American tradition, Andrew Feenberg, has pointed out, the early development of critical theory and Lukacs’ philosophy cannot be understood without reflecting on the historically rich network between phenomenology, Neo-Kantianism, and social theory. Moreover, in contradistinction to many contemporary critical theorists, Feenberg, following Lukacs, is not hostile to epistemological and ontological questions in social theory. In this vein, the main term that Feenberg introduces in his interpretation of Lukacs is Gegenstandlichkeit (objectivity). Although I agree with Feenberg’s claim that this term is central for understanding Lukacs’ understanding of social entities as culturally meaningful entities, I argue that we can find this broader social meaning of entities already foreshadowed in Chap. 1 of Marx’s Capital if we read Capital as a theory of society. Unfortunately, traditional Marxist discourses tend to reduce Capital to an “economic” theory and Feenberg seems to follow this tradition, that is, he seems to dismiss the critique of political economy as the primary horizon for a critical theory of society. However, as I will demonstrate, Marx’s project cannot be reduced to a labor theory of value and, instead, it should, from the beginning, be understood as a social theory based on social categories; and Gegenstandlichkeit serves as the central element for translating epistemological concepts into social concepts.

The thesis of my remarks is that Piketty’s overall position understands capital as something that exists within society, whereas I submit (on the grounds of Marx’s theory of society) that capital is the main category that determines the existence of capitalist society. Put differently, capital in the form of valorized labor determines the specific social form of capitalist society. Whereas Piketty’s position is built upon a positivistic concept of capital, I argue that capital is not ‘some-thing’; rather, capital is the central category of capitalist social reproduction. Capital, in other words, must describe the functioning of a social totality as a whole and cannot be related to a single aspect of it. Accordingly, though the focus on inequality is important, it tends to hide the real social organization of capitalist society.

In this paper a Moving Least Squares method (MLS) for the simulation of 2D free surface flows is presented. The emphasis is on the governing equations, the boundary conditions, and the numerical implementation. The compressible viscous isothermal Navier–Stokes equations are taken as the starting point. Then a boundary condition for pressure (or density) is developed. This condition is applicable at interfaces between different media such as fluid–solid or fluid–void. The effect of surface tension is included. The equations are discretized by a moving least squares method for the spatial derivatives and a Runge–Kutta method for the time derivatives. The computational frame is Lagrangian, which means that the computational nodes are convected with the flow. The method proposed here is benchmarked using the standard lid driven cavity problem, a rotating free surface problem, and the simulation of drop oscillations. A new exact solution to the unsteady incompressible Navier–Stokes equations is introduced for the rotating free surface problem.

Mueller microscopy studies of fixed unstained histological cuts of human skin models were combined with an analysis of experimental data within the framework of differential Mueller matrix (MM) formalism. A custom-built Mueller polarimetric microscope was used in transmission configuration for the optical measurements of skin tissue model adjacent cuts of various nominal thicknesses (5 to 30 mm). The maps of both depolarization and polarization parameters were calculated from the corresponding microscopic MM images by applying a logarithmic Mueller matrix decomposition (LMMD) pixelwise. The parameters derived from LMMD of measured tissue cuts and the intensity of transmitted light were used for an automated segmentation of microscopy images to delineate dermal and epidermal layers. The quadratic dependence of depolarization parameters and linear dependence of polarization parameters on thickness, as predicted by the theory, was confirmed in our measurements. These findings pave the way toward digital histology with polarized light by presenting the combination of optimal optical markers, which allows mitigating the impact of tissue cut thickness fluctuations and increases the contrast of polarimetric images for tissue diagnostics.

After briefly criticizing Honneth's recent reconceptualization of reification as (1) psychological and (2) noneconomic, I outline the problem of reification from the perspective of Marx, which prepares the confrontation that I present between Heidegger and Marx, for the real issue is whether reification is the result of technology (which I will call “causality form”) or the result of the “commodity form.” I claim, against Heidegger, that Marx's concept of the commodity form is not based on subjectivity and, in addition, that Heideggerian ontology is unable to explain the connection between “enframing” and the capitalist structures that Heidegger implies in his descriptions of modern phenomena. Accordingly, this essay tries to open a new path towards what has recently been called “Heideggerian Marxism.”

“The (In)Visibility of Capital. Reflections on Film, Lukacs, and Contemporary Critical Realism” presents critical reflections on the possibility of a contemporary concept of aesthetic realism in connection with two photo artists and filmmakers, Edward Burtynsky and Allan Sekula, both concerned with globalization, the exploitation of the earth, labor, and global capital in their work. The basic question connected with their work is whether it is possible to represent the real abstractions of capital and the effects of global capital in images, photography, and other works of art. Lotz argues that Burtynsky’s work ultimately mystifies reality and falls back onto a subjective aesthetical position and discusses the possibility of renewing Lukacs’ concept of realism and mimesis for contemporary critical aesthetics.

Financing for peacebuilding has increased significantly and there are signs that it may continue to grow in the next few years. However, aid for peacebuilding is also characterised by problematic trends, including the existence of ‘aid orphans’, and volatility and delays of allocations. In order to reverse these trends and sustain higher levels of financing for peacebuilding, a broader concept of aid effectiveness is required that is better adapted to countries affected by conflict and fragility. Much of the debate has been focused on the advantages of pooled funds, but there is a need for a mix of aid instruments to achieve aid effectiveness.

I argue from a hermeneutic point of view that formal elements of poetry can only be identified because poetry is based on both the phenomenon and the conception of poetry, both of which precede the attempt to identify formal elements as the defining moment of poetry. Furthermore, I argue with Gadamer that poetry is based on a rupture with and an epoche of our non-poetic use of language in such a way that it liberates “fixed” universal aspects of everyday language, and that through establishing itself in a new, self-referential and monologue unity, it individualizes speech. From the hermeneutic position, poetry is a form of speaking rather than a “fixed” object. As such, I will try to make sense of what Paul Celan said in his famous “Meridian” speech: namely, that the poem is “actualized language, set free under the sign of a radical individuation, which at the same time stays mindful of the limits drawn by language, the possibilities opened by language.”

STATEBUILDING IS WIDELY RECOGNIZED AS A CENTRAL CHALLENGE FOR THE international order today and the main response to a range of global problems from poverty to terrorism and international crime. However, there is no agreement about why and how international actors should engage in statebuilding processes. Donor governments and international agencies often justify and legitimize their statebuilding support by referring to international norms, such as human rights. Others, especially in the academic community but also some development professionals, question the relevance of these norms, in particular, in fragile states that are unable or unwilling to live up to them and have only limited means of exercising their sovereignty. They argue that statebuilding is essentially a local process that only works if it is based on local norms and values and led by national actors. For instance, an aid worker said in an interview on Deutsche Welle recently about the situation in Darfur: "We should listen to the local actors more. They know much better how to solve their own conflicts than anyone else. We must also accept the fact that we deal with very different societies who don't always want to develop in the direction we want them to or think they should." (1) By looking at this problem from a pragmatic perspective that emphasizes progress through practical engagement, it becomes clear that the two positions are not as different and irreconcilable as they first appear. On one hand, there is a growing body of evidence of the possible harm that excessive or untimely insistence on international norms may cause. This evidence demands a stronger realism and a clearer balance between the respect for international norms and an understanding and appreciation of the national context. However, the evidence does not contradict the fundamental relevance and importance of international norms. On the contrary, it shows how international actors can strengthen progress toward international norms on a pragmatic basis by being less principled and rigid. On the other hand, a pragmatic approach also makes it clear that international norms are already known and accepted by many national statebuilding actors and people in fragile situations. They are increasingly included as the basis for peace agreements and represent hope and opportunities. International interventions in fragile situations often run the risk of doing harm by causing tensions and fragmentation of societies if they are not sensitive enough to the political, historical, and cultural context. However, it can be questioned if international actors fully recognize the motivation that international norms provide for national statebuilding actors in fragile situations, and the opportunities for progress that they create. A pragmatic approach to statebuilding demands a discussion and a rethinking of current concepts and practices. We need to understand better what the sources of international norms are, what dilemmas and trade-offs are involved in their application, and how mechanisms for engaging national statebuilding actors work. This discussion should lead international statebuilding actors to clarify their own role in promoting normative standards in fragile situations in a number of ways that would help to strengthen progress. Are International Norms Relevant for Statebuilding? International norms are as old as the sovereign state itself, going back to the Peace of Westphalia, which contained provisions that states must respect religious freedom and remove barriers to trade as part of the settlement after the Thirty Years' War. Charles Tilly famously said that "war makes states" through internal processes of concentration of power and wealth in preparation for warfare. However, he also described how mutual recognition among states that are able to effectively challenge each other in war is an important source of state legitimacy, and how external compacts among states gradually led to stronger constraints on the form of states. …

Friction in the piston ring package (piston, piston rings, and liner) is a major source of power consumption in large two-stroke marine diesel engines. In order to improve the frictional and wear performance, knowledge about the tribological interface between piston rings and liner is needed. The work described in this article addresses the subject from both an experimental and a theoretical perspective. First, a one-dimensional numerical model based on the Reynolds equation is presented. It uses a pressure—density relation for the modelling of cavitation. The viscosity is assumed to depend on a measured temperature only; thus, it is not necessary to include the energy equation. Conservation of oil is ensured throughout the domain by considering the amount of oil outside the lubricated interface. A model for hard contact through asperities is also included. Second, a laboratory-scale test rig is described. Results from a number of experimental tests with different geometries and running speeds are presented. Finally, a comparison between the measured friction force and simulated values is given. Good correlation between the measurements and the simulations has been observed, especially when running at a high speed. This article represents the first steps in the pursuit of being able to accurately model the interface between a piston ring and the cylinder liner in large two-stroke diesel engines.

Against a stream of culturally oriented scholars some scholars in aesthetics, such as Arthur Danto and Noel Carroll, have maintained that there is a sense of “seeing” and visual recognition that does not depend upon historical and cultural practices. This essay shows that Danto’s assumption of a difference between a “core” and an “extended” form of perception and visual recognition should be rejected. The underlying argument of my considerations in this essay is the following: the distinction between a “pure” and an “extended” perception or visual perception is untenable, since, as a phenomenological reflection can reveal, our normal mode of perception is always extended. In this vein, it is argued here that there is, after all, only one mode of perception and that Danto’s position is based on abstractions from the real phenomenon. Consequently, whereas Danto maintains that it makes sense to talk about a “natural” form of seeing, this essay argues that “seeing” is itself a culturally defined way of comportment, and that assumptions about naturalistically defined perceptual core processes turn out to be idealized constructions.