Cut Boundaries Research Articles

Introduction to the Special Issue Sacred Heritage: Religions and Material Culture

In recent years, studies dedicated to relations between “religion” and “heritage” have apparently shifted from questions concerned with the dichotomy and tensions between these two domains (see Meyer and de Witte 2013) towards a scrutinization of their complex entanglements and not so clear cut boundaries (see e [...]

Prediction of bone ingrowth into a porous novel hip-stem: A finite element analysis integrated with mechanoregulatory algorithm.

Bone ingrowth into a porous implant is necessary for its long-term fixation. Although attempts have been made to quantify the peri-implant bone growth using finite element (FE) analysis integrated with mechanoregulatory algorithms, bone ingrowth into a porous cellular hip stem has scarcely been investigated. Using a three-dimensional (3D) FE model and mechanobiology-based numerical framework, the objective of this study was to predict the spatial distribution of evolutionary bone ingrowth into an uncemented novel porous hip stem proposed earlier by the authors. A CT-based FE macromodel of the implant-bone structure was developed. The bone material properties were assigned based on CT grey value. Peak musculoskeletal loading conditions, corresponding to level walking and stair climbing, were applied. The geometry of the implant-bone macromodel was divided into multiple submodels. A suitable mapping framework was used to transfer maximum nodal displacements from the FE macromodel to the cut boundaries of the FE submodels. CT grey value-based bone materials properties were assigned to the submodels. Thereafter, the submodels were solved and simulations of bone ingrowth were carried out using mechanoregulatory principle. A gradual increase in the average Young's modulus, from 1200 to 1500 MPa, of the bone tissue layer was observed considering all the submodels. The distal submodel exhibited 82% of bone ingrowth, whereas the proximal submodel experienced 65% bone ingrowth. Equilibrium in the bone ingrowth process was achieved in 7 weeks postoperatively, with a notable amount of bone ingrowth that should lead to biological fixation of the novel hip stem.

A weighted shifted boundary method for immersed moving boundary simulations of Stokes' flow

The Shifted Boundary Method (SBM) belongs to the class of unfitted (or immersed, or embedded) finite element methods, and relies on reformulating the original boundary value problem over a surrogate (approximate) computational domain. The surrogate domain is constructed so as to avoid cut cells and the associated problematic implementation and numerical integration issues. Accuracy is maintained by modifying the original boundary conditions using Taylor expansions: hence the name of the method, that shifts the location and values of the boundary conditions. In this article, we extend the SBM to the simulation of incompressible Stokes flow, by appropriately weighting its variational form with the elemental volume fraction of active fluid. This approach allows to drastically reduce spurious pressure oscillations in time, which are produced if the total volume of active fluid were to change abruptly over a time step. The proposed Weighted SBM (W-SBM) exactly preserves states of hydrostatic equilibrium, and induces small mass and momentum conservation errors, which converge as the grid is refined. This is in analogy to cutFEMs and related unfitted approaches, which rely on an affine representation of cut boundaries. We demonstrate the robustness and accuracy of the proposed method with an extensive suite of two-dimensional tests.

Refugee Chronicles: excerpt from the diary with an introduction

The following text is an excerpt from The Refugee Chronicles, a fictional diary written by Evgeny Shtorn, poet and activist, from his experience of seeking asylum. Shtorn had to flee Russia due to the government’s hostile policies toward both queer sexualities and political dissent right after he was interviewed by the Russian secret police FSB in 2018. The run for life and liberty brought him to the utmost end of Western Europe, Ireland. Shtorn’s experience of claiming asylum made him question clear cut boundaries between the West and the East along the lines of guarantees and protections of human rights. He also noted how queer sexuality plays a specific role in the asylum application process as a protected and even desired ground for granting refugee status. His experience of a lengthy stay in the dormitory for asylum seekers converted into a book-length, semi-fictional chronicle was published by an independent press, Poryadok Slov, in St. Petersburg, Russia. The book is full of queries, ambiguities, and doubts that surround the issues of queerness, migration, and the politics of human rights. The following chapter is introduced with a short pre-word by a scholar of sexuality studies Alexander Kondakov who offers a brief contextualization and conceptualization of The Refugee Chronicles.

Boundary curvature guided programmable shape-morphing kirigami sheets

Kirigami, a traditional paper cutting art, offers a promising strategy for 2D-to-3D shape morphing through cut-guided deformation. Existing kirigami designs for target 3D curved shapes rely on intricate cut patterns in thin sheets, making the inverse design challenging. Motivated by the Gauss-Bonnet theorem that correlates the geodesic curvature along the boundary with the Gaussian curvature, here, we exploit programming the curvature of cut boundaries rather than the complex cut patterns in kirigami sheets for target 3D curved morphologies through both forward and inverse designs. The strategy largely simplifies the inverse design. Leveraging this strategy, we demonstrate its potential applications as a universal and nondestructive gripper for delicate objects, including live fish, raw egg yolk, and a human hair, as well as dynamically conformable heaters for human knees. This study opens a new avenue to encode boundary curvatures for shape-programing materials with potential applications in soft robotics and wearable devices.

Governance dynamics in rangelands: An evaluation of the applicability of Ostrom's principles in the Western Highlands of Cameroon

Rangeland ecosystems represent key natural resource settings where sustainability issues linked to their governance, use and management abound. Growing pressure and the consequent unsustainable use of sub-Saharan Africa's rangelands continue to attract scientific and policy interests. Cameroon bears eloquent testimony to the current lethargy; despite threats of rangeland transformation, not enough empirical evidence exists on the manifestations of communal-based governance processes that shape the sustainability of rangelands. We contribute to provide this evidence by: (1) Mapping actors’ interests around rangelands, and (2) Exploring the manifestations of Ostrom principles, and the sustainability of their resource use outcomes. Twelve key informant interviews, complemented by 10 focus group discussions were used to generate relevant data, complemented by document analysis. We employed thematic analysis and narratives, to derive the following conclusions: (i) While state actors’ interests revolve around disease control and conflict management, non-state, especially community-based actors, demonstrate interest on the resource use components of rangelands. These divergent interests further threaten the sustainability of rangelands. (ii) State and community actors’ interests overlap with regards to securing pasture in rangelands. (iii)While rangeland boundaries were hardly clearly defined, collective voice and participation were found to be significantly present amongst pastoralists. Self-governed community arrangements were hardly achieved without the direct and/or indirect facilitation of state actors and catalyzing agents. The results suggest the need for the institutionalization of clear cut boundaries. This should be accompanied by a new governance arrangement - a jelled institutional platform which breeds legitimacy from both formal and informal rangeland actors. Further quantitative empirical evidence is needed to ground this assertion.

Temporal information based GoP adaptation for linear video delivery schemes

An original wireless video transmission scheme called SoftCast has been recently proposed to deal with the issues encountered in conventional wireless video broadcasting systems (e.g. cliff effect). In this paper, we evaluate and optimize the performance of the SoftCast scheme according to the transmitted video content. Precisely, an adaptive coding mechanism based on GoP-size adaptation, which takes into account the temporal information fluctuations of the video, is proposed. This extension denoted Adaptive GoP-size mechanism based on Content and Cut detection for SoftCast (AGCC-SoftCast) significantly improves the performance of the SoftCast scheme. It consists in modifying the GoP-size according to the shot changes and the spatio-temporal characteristics of the transmitted video. When hardware capacities, such as buffer or processor performance are limited, an alternative method based only on the shot changes detection (AGCut-SoftCast) is also proposed. Improvements up to 16 dB for the PSNR and up to 0.55 for the SSIM are observed with the proposed solutions at the cut boundaries. In addition, temporal visual quality fluctuations are reduced under 1dB in average, showing the effectiveness of the proposed methods.

Surface quality evaluation of single crystal 4H-SiC wafer machined by hybrid laser-waterjet: Comparing with laser machining

Single crystal silicon carbide (SiC), as a 3rd generation semiconductor material, has a wide application range and development prospect, especially in some key fields such as defense and aerospace industries. It's a typical difficult-to-machine and hard-brittle material due to its high hardness and brittleness. A hybrid laser-waterjet micromachining technology was employed to implement near damage-free and high-efficient micromachining of single crystal SiC. The workpiece material is heated by laser to a temperature near but below its melting point. The material is under an extremely “softened” but still solid status. A waterjet is applied off-axially to expel the heating-softened material and cool the material to eliminate thermal damage. It combines the advantages of laser processing with those of waterjet cutting. Moreover, it's a green machining approach, which is pollution-free and recyclable. In the present study, the surface quality of single crystal 4H-SiC machined by the hybrid laser-waterjet is evaluated and compared with that machined by laser. Among the wafers respectively machined by laser, under-water laser, waterjet-assisted laser and the hybrid laser-waterjet, the one machined by the hybrid laser-waterjet is with the best surface quality. Its cut boundaries between the machined area and the unmachined area are clear, the cut edges are straight, also the cut sides are clean. On the contrary, there is severe thermal damage along the cut edges and cut sides of laser machining. The microgrooves obtained from the hybrid laser-waterjet micromachining are with V-shaped cross-sections and the transition between the cut edge and the unmachined surface is flat and smooth. The cross-section profile of the microgroove machined by laser is M-shaped and there are obvious humps along the two sides of the microgroove. The microgroove bottom is almost at the same height with the unmachined surface. Besides, there are HAZs with a width of 50–100 µm and scaly recast layers on the sides of the cut machined by laser. In contrast, there is no recast layer and HAZ on the cut side of the hybrid laser-waterjet micromachining. The texture of the cut sidewall is clear and with the typical features of the material removed under the plastic mode. The EDS results show that the oxidation behavior happens during both the hybrid laser-waterjet micromachining and laser machining. However, the content of silicon dioxide generated in the hybrid laser-waterjet micromachining process (the oxygen content is about 5%) is obviously lower than that generated in laser machining (the oxygen content is more than 30%).

Serving some and serving all: how providers navigate the challenges of providing racially targeted health services

ABSTRACTObjectives: Racially targeted healthcare provides racial minorities with culturally and linguistically appropriate health services. This mandate, however, can conflict with the professional obligation of healthcare providers to serve patients based on their health needs. The dilemma between serving a particular population and serving all is heightened when the patients seeking care are racially diverse. This study examines how providers in a multi-racial context decide whom to include or exclude from health programs.Design: This study draws on 12 months of ethnographic fieldwork at an Asian-specific HIV organization. Fieldwork included participant observation of HIV support groups, community outreach programs, and substance abuse recovery groups, as well as interviews with providers and clients.Results: Providers managed the dilemma in different ways. While some programs in the organization focused on an Asian clientele, others de-emphasized race and served a predominantly Latino and African American clientele. Organizational structures shaped whether services were delivered according to racial categories. When funders examined client documents, providers prioritized finding Asian clients so that their documents reflected program goals to serve the Asian population. In contrast, when funders used qualitative methods, providers could construct an image of a program that targets Asians during evaluations while they included other racial minorities in their everyday practice. Program services were organized more broadly by health needs.Conclusion: Even within racially targeted programs, the meaning of race fluctuates and is contested. Patients’ health needs cross cut racial boundaries, and in some circumstances, the boundaries of inclusion can expand beyond specific racial categories to include racial minorities and underserved populations more generally.

Store format choice and shopping trip types

PurposeThe purpose of the paper is to identify store format attributes that impact on store format choice when consumers conduct fill‐in or major trips to buy groceries. By doing so, we take into consideration that consumers patronise multiple (store based) formats depending on the shopping situation operationalised by the type of shopping trip.Design/methodology/approachThe paper adopts the conceptual framework of random utility theory via application of a multinomial logit modelling framework. The analysis is based on a survey of 408 consumers representing households in a clearly defined central European retail area.FindingsThe results reveal a considerable moderating effect of the shopping situation on the relationship between perceived store format attributes and store format choice. Consumers' utilities are significantly higher for discount stores and hypermarkets when conducting major trips. To the contrary, supermarkets are preferred for fill‐in trips in the focussed retail market. Merchandise‐related attributes of store formats have a higher impact on the utility formation regarding major‐trips, whereas service‐ and convenience‐related attributes do so with regards to fill‐in trips.Research limitations/implicationsThe findings can only be generalised to retail markets with similar characteristics to the one under study. It is highly concentrated, contains a considerable share of small size retail stores, it is urban and has clear cut boundaries due to its geographical location.Originality/valueThis paper considers the fact that consumers patronise multiple store formats and investigates the moderating effect of the shopping situation – operationalised by different types of shopping trips – on store format choice.

Image Restoration with a Truncated Gaussian Model

The Gaussian model for image restoration has the problem of positive probability densities for pixels outside the realistic range. To solve this problem, we introduce a truncated Gaussian model (TG model). In this model, the tails of the Gaussian distribution are cut off at upper and lower bounds and are replaced by δ peaks at the cut boundaries. We analytically obtain the average performance of the TG model in a mean-field system by solving exactly the infinite-range model and using the replica method. We also compare the infinite-range model to the more realistic two-dimensional case by Monte Carlo simulations. When modeling the TG model, we introduce a generalized prior probability. This prior probability includes the Gaussian, Ising, Q-Ising spin, and TG model as special cases. Thus, we can choose an appropriate model depending on the statistical properties of the images.

Detection of hard cuts and gradual transitions from video using fuzzy logic

In this paper, we introduce a novel approach for the detection and classification of shot boundaries based on interval type-2 fuzzy logic. We consider fuzzy low level features (Fuzzy Histogram (FH) and Fuzzy Co-occurrence Matrix (FCM)) and evaluate a fuzzy rule base modelled by interval type-2 sets to detect cut boundaries. After detection of cuts, a recovery mechanism is used to reduce false positives caused by illumination variation (e.g., camera flash light). The fuzzy rules used for gradual transition form a unified approach to detect various types gradual transitions like dissolves, fades and wipes, by a single method. Test results indicate that very high precision and recall could be achieved for the test videos, particularly the recall value of gradual transitions.

Aufbau von markierten Pluralklassen im Deutschen — eine Herausforderung für die Markiertheitstheorie

In addition to the two regular plural markers -en and -e for strong and weak inflection (Banken, Jahr-e) with their morphonological variants -n and -0 (Ranke-n, Fahrer-0) German has employed plurals with umlaut (Wolf-e, Vater-0) and in -er (Huhn-er) since Early New High German and, more recently, plurals in -s which establish a new plural class in German (Uhus, Mullers, Hochs und Tiefs). This formation of a new plural class, however, severely contradicts the assumptions of Markedness Theory, according to which language change should lead to a decline in markedness, to a reduction of the diversity of forms, but not to the formation of an additional class. The paper will show that development and function of the umlaut plural and the -er plural can be explained as substitutions for the -e plural subjected to apocope in Early New High German and as better realizations of the naturalness principle of uniqueness, whereas the -s plural can be accounted for in terms of transparency requirements which, in some word classes, dominate all other naturalness principles including those of optimal word length and implicational paradigm structure. Since the specific word classes that form an -s plural in German share joint features, I will assume a specific 'transparency domain' for these nouns. On the one hand, the phonologically or semiotically special characteristics of these nouns motivate the emergence of a new plural class, on the other hand, they define relatively clear cut boundaries. The motivation for the different plural forms, their development and even their decline will be explained in the framework of Markedness Theory by competing naturalness principles.

MISCIBILITY BEHAVIOUR OF POLY(ETHER SULPHONE)/NYLON-6 BLENDS

Binary blends of poly (ether sulphone) (PES) and Nylon-6 were prepared in a whole range of composition by melt extrusion. Miscibility behaviour of the blends were studied using thermal analytical techniques like differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Due to the rapid crystallization of Nylon-6 as it is cooled from the melt state, its glass transition behaviour could not be detected even in the quenched samples by DSC. Furthermore, the crystallization and melting behaviour of the blends have been studied by DSC. DMA results show that the dynamic storage modulus of the blends were in-between those of the constituent polymers. Also the glass transition of Nylon-6 phase as determined by the peak in loss tangent remains constant which shows that the two polymers are immiscible. Thermal expansion coefficient of the blends as determined by TMA is greater than that of Nylon-6 signifying the increased dimensional stability of the blends at higher temperatures. Morphological studies done by scanning electron microscopy (SEM) show the biphasic nature of the blends, with clear cut boundaries between the phases because of poor interfacial adhesion. Dispersed particle size is small when Nylon-6 is the dispersed phase because of its lower melt viscosity as compared to PES. Thermal stability of the blends was measured using thermogravimetric analysis (TG). Two-step decomposition behaviour was observed because of macro-phase separated morphology.

A Cayley tree immune network model with antibody dynamics

A Cayley tree model of idiotypic networks that includes both B cell and antibody dynamics is formulated and analysed. As in models with B cells only, localized states exist in the network with limited numbers of activated clones surrounded by virgin or near-virgin clones. The existence and stability of these localized network states are explored as a function of model parameters. As in previous models that have included antibody, the stability of immune and tolerant localized states are shown to depend on the ratio of antibody to B cell lifetimes as well as the rate of antibody complex removal. As model parameters are varied, localized steady-states can break down via two routes: dynamically, into chaotic attractors, or structurally into percolation attractors. For a given set of parameters percolation and chaotic attractors can coexist with localized attractors, and thus there do not exist clear cut boundaries in parameter space that separate regions of localized attractors from regions of percolation and chaotic attractors. Stable limit cycles, which are frequent in the two-clone antibody B cell (AB) model, are only observed in highly connected networks. Also found in highly connected networks are localized chaotic attractors. As in experiments by Lundkvist et al. (1989. Proc. natn. Acad. Sci. U.S.A. 86, 5074-5078), injection of Ab1 antibodies into a system operating in the chaotic regime can cause a cessation of fluctuations of Ab1 and Ab2 antibodies, a phenomenon already observed in the two-clone AB model. Interestingly, chaotic fluctuations continue at higher levels of the tree, a phenomenon observed by Lundkvist et al. but not accounted for previously.

The Jurassic-Cretaceous boundary: problems of definition and procedure

Problems with the Jurassic-Cretaceous (J-K) boundary are largely the result of stratigraphic difficulties caused by a lack of a significant faunal turnover at either boundary of the Berriasian stage, and to extreme faunal provincialism as a consequence of the Purbeckian regression. There is also a lack of agreement about basic principles of procedure, which could be resolved if we accept that system boundaries are conventional boundaries. The choice of boundary level depends primarily on its correlation potential. This would put an end to fruitless discussions about whether Berriasian faunas are Jurassic or Cretaceous. Continuity of usage is another important factor. For this reason the efforts of the International Working Group on the Jurassic-Cretaceous Boundary have been concentrated on the Tethyan-Boreal correlation of the Tithonian-Berriasian boundary, though so far with limited success. Other levels should be tested in future. Another problem in inter-regional correlation is the lack of clarity in the underlying zonal concept. Fossil zones are traditionally biochronologic units based on evolutionary events. Therefore a clear distinction between biostratigraphic raw data and their biochronologic interpretation is absolutely necessary. System boundaries have to be defined by global boundary stratotype section and point (GSSP) according to the guidelines of the International Commission on Stratigraphy (ICS). This definition would normally start from a biochronologic marker level. It should be emphasized that only range zones, delimited by phyletic events, have unequivocal boundaries. Traditional ammonite zones (Oppel zones) are more loosely defined by their contents and have no clear cut boundaries. This should be taken into consideration when deriving the boundary definition from an ammonite zonation.

Using Isopleth Maps of Landslide Deposits as a Tool in Timber Sale Planning

Timber sales on the Sierra National Forest are encountering increasing landslide hazard. Soil loss from debris flows can lead to long-term losses in forest productivity. Isopleth mapping of landslide deposits is the technique currently employed to estimate relative landslide susceptibility for planning timber sales and harvest activities that minimize soil erosion. Established procedures are used to transform landslide inventory maps into isopleth maps. Relative landslide susceptibility is defined by the percent of a standard area underlain by landslides. Hazard zonation of the timber sale is defined by contours of certain percent values: a) negligible (less than 1 percent), b) low (1–10 percent), c) moderate (10–30 percent), d) high (30–50 percent), e) very high (50–70 percent), and f) extreme (70–100 percent). This quantitative approach permits consistent representation of anticipated landslide hazard between different areas. Isopleth maps identify whether landslide hazard poses a critical concern early in the process of planning a timber sale. For example, twelve of twenty-eight proposed timber sales involved areas with only negligible or low landslide susceptibility. Where susceptibility was greater, specific areas requiring detailed field investigation were readily identified. The degree of landslide activity and related on-site conditions lead to formulation of recommendations for adjusting cut unit boundaries, harvest method, or road design. This timely assessment of landslide hazard reduces the need for last minute adjustments in sale plans or the consequence of landslide occurrence after harvest.