Identical Pieces Research Articles

The Equivalency Principle for Discounting the Value of Natural Assets: An Application to an Investment Project in the Basque Coast

Making decisions about optimal investments in green infrastructure necessitates setting social discount rates. This paper suggests a practical way for determining the discount rate for projects or programmes in which one of the options is to maintain or restore land to an undeveloped state. We propose an “equivalency principle” to derive a simple rule that sets the discount rate. The rule is based on the premise that the long term value of a piece of undeveloped land ought to be at least the same as the value of an identical piece of land in the vicinity to which permission has been granted for development. We illustrate this principle with various case studies and we apply it to a contentious investment project in the Basque Country associated with the regeneration of a large scale harbour that involves reclaiming undeveloped land that has important ecological values, including for the conservation of a marine ecosystem.

MODELO TEÓRICO PARA PREDECIR EL LUGAR DEL CORTE Y OPTIMIZAR LA EXTRACCIÓN DE LA PULPA EN COCO

Coconut is an important crop produced in Mexican coastal regions. Coconut is sold as fresh water and dried pulp is used to produce vegetable oil. An industrial plant for fresh water extraction lets pulp as residue, which should be also sold. Workers have a great ability to extract coconut pulp after the shells are sun-dried for half a day. A machine for on-line pulp extraction has to be designed, requiring that coconut is sliced in two identical shell pieces for both: transversal and longitudinal cuts. A vision system acquired images from the sliced coconuts obtaining its circularity and Feret diameter. Coconuts cut transversally used a model that measured coconut length with a linear differential transformer; 93 % of the tests presented two identical shells. A simulation was carried out for positioning a round extractor for separating the pulp from the shell. When the centroide was used as the control coordinate pulp losses were over 35 %; a model for positioning the extractor decreased pulp losses to less than 16 %.

From Underworld to Avant-Garde:

From Underworld to Avant-Garde:

From Underworld to Avant-Garde:

From Underworld to Avant-Garde:

Continuous Limits of Classical Repeated Interaction Systems

We consider the physical model of a classical mechanical system (called “small system”) undergoing repeated interactions with a chain of identical small pieces (called “environment”). This physical setup constitutes an advantageous way of implementing dissipation for classical systems; it is at the same time Hamiltonian and Markovian. This kind of model has already been studied in the context of quantum mechanical systems, where it was shown to give rise to quantum Langevin equations in the limit of continuous time interactions (Attal and Pautrat in Ann Henri Poincare 7:59–104, 2006), but it has never been considered for classical mechanical systems yet. The aim of this article is to compute the continuous limit of repeated interactions for classical systems and to prove that they give rise to particular stochastic differential equations (SDEs) in the limit. In particular, we recover the usual Langevin equations associated with the action of heat baths. In order to obtain these results, we consider the discrete-time dynamical system induced by Hamilton’s equations and the repeated interactions. We embed it into a continuous-time dynamical system and compute the limit when the time step goes to 0. This way, we obtain a discrete-time approximation of SDE, considered as a deterministic dynamical system on the Wiener space, which is not exactly of the usual Euler scheme type. We prove the Lp and almost sure convergence of this scheme. We end up with applications to concrete physical examples such as a charged particle in a uniform electric field or a harmonic interaction. We obtain the usual Langevin equation for the action of a heat bath when considering a damped harmonic oscillator as the small system.

Crazy-Cuts: From Theory to App

Please send all submissions to the Mathematical Entertainments Editor, Ravi Vakil, Stanford University, Department of Mathematics, Bldg, 380, Stanford, CA 94305-2125, USA e-mail: vakil@math.stanford.edu C razy-Cut puzzles are fascinating and often quite challenging: Given a planar shape (as for example depicted inFigure 1a), finda cutting curve thatdivides the shape into two parts, identical up to Euclidean transformations (rotations and translations). The solution, as seen in Figure 1b, is not trivial to find. Several further Crazy-Cut dissectionpuzzles are shown inFigures 2and12.Apparently, suchpuzzles were invented byHenry Dudeney (see Eriksson [1]) about one hundred years ago, but it was Martin Gardner whopopularized them in the 1970s in his Scientific American column [2] and in his books [3]. Gardner also posed the challenge of finding a formal algorithm for solving Crazy-Cut puzzles. In this article, we describe some recent work on algorithms for solving Crazy-Cut challenges that led to the designofapuzzlegameforsmart-phonesandpadcomputers. Eriksson was the first to propose an algorithm for solving polygonal Crazy-Cut challenges [1]. In Eriksson’s algorithm, two points on the perimeter of the shape are selected, and, starting from these points, two congruent paths are constructed, one of them (the ‘‘master’’) leads by following the boundaryof the shape,whereas the secondpath (the ‘‘slave’’) is led by the congruence constraint and is allowed to cross the shape. If the two starting points happen to be in ‘‘correspondence’’ when there is a solution to the challenge, the ‘‘slave’’ path will split the shape into two identical pieces; see an example in Figure 3. Eriksson proved that by checking all possible pairs of points, one will find the correct cut if such a cut exists or will determine that the shape cannot be cut into two identical parts. Following Eriksson’s work, Rote, with co-workers, improved and further elaborated upon Eriksson’s algorithm [4, 5]. El-Khechen et al. then proposed an algorithm for a variant of theproblem inwhich the twopieces are required to be mirror congruent, that is, identical up to reflection, rotation, and translation [6]. A previous work by the second and third authors of this article reconsidered Crazy-Cut puzzles from a different point of view. Quoting [7]: ‘‘We first analyze the inverse problem of assembling a planar shape from two identical shapes that have partially matching boundaries. This problem may be regarded as solving a simple jigsaw puzzle of two pieces (with no drawings on them).’’ Then the self-docking analysis readily provides a Crazy-Cut algorithm, and more importantly for us here, the insights also provide the mathematical basis required to design Crazy-Cut riddles systematically. In this work, we improve on our previous analysis, thereby enabling a simpler Crazy-Cut algorithm. Furthermore, based on the improved analysis, a formal method to design Crazy-Cut riddles is proposed.

Inflexible Bodies

[T]he power relations that characterize any historically embedded society are never as transparently clear as names we give to them imply.- Gordon, 1997, p. 3While librarians are strongly encouraged to offer materials from a variety of identity perspectives (J. Taylor) to make library collections more welcoming to transgender people, same level of attention is not always applied to terminology used to describe transgender- related topics, and even trans- people themselves. Is it possible for librarians to use controlled vocabulary to accurately describe people's lives? What pieces of identity are leftbehind? In traditional library cataloging models, hierarchical taxonomic and classification structures are used to describe pieces of information. These schemas are lacking in any sort of mechanism to acknowledge people's sometimes amorphous and often fluid identities. This paper will specifically address Library of Congress-based cataloging practices, including classification, and their role in enforcing normative boundaries for sexualities and gender. Through use of inaccurate language in Library of Congress Subject Headings (LCSH) and problematic classification schemes, catalogers often unwittingly contribute to creation of library environments that are passively hostile to transgender users.The idea that Library of Congress subject headings do a poor job of codifying reality is not new. Sanford Berman first addressed this issue in late 1960s. He wrote, in Prejudices and Antipathies:[...] LC list can only satisfy parochial, jingoistic Europeans and North Americans, white- hued, at least nominally Christian (and preferably Protestant) in faith, comfortably situated in middle- and higher- income brackets, largely domiciled in suburbia, fundamentally loyal to Established Order, and heavily imbued with transcendent, incomparable glory of Western civilization (3).He is far from alone in this sentiment; in their 2001 analysis, Hope Olson and Rose Schegl found 68 works discussing negative bias in LCSH. Many of these works were critical of way Library of Congress (LC) provides access to materials about women, African studies, people with disabilities, and LGBT people (Olson and Schegl 61). This paper focuses on latter.Queers or Sexual Minorities?It is simultaneously essential and impossible to extricate transgender identities from lesbian, gay, and bisexual identities; queer- identified transgender people certainly exist, though LGBTQ advocacy work has not always been inclusive of both sexual and gender diversity. As mainstream and groups in 1950s and 1960s began presenting as normally as possible in order to gain widespread acceptance, transgender identities were often considered deviant and misaligned with groups' goals (Stryker 151). In other decades, such as 1970s and 1990s, transgender and activists often aligned in hopes of creating imagined political alliance of all possible forms of gender antinormativity (146). Echoes of these tactics are still very common in different types of LGBTQ rhetoric, and controlled library vocabulary is definitely not immune.For purposes of this work, queer is defined as a politicized identity centered on same- sex orientation. The word queer has complicated meanings. In early twentieth century, it was an internal term used by people within community, only becoming an insult in 1950s (Shneer and Aviv). In late 1980s and early 1990s, queer regained popularity, representing resistance to assimilative lesbian and gay language (Warner xxi). Currently, it still retains some of those radical connotations, threatening the ground on which and politics has been built, taking apart ideas of a 'sexual minority' and a 'gay community,' indeed of 'gay' and 'lesbian' and even 'man' and 'woman.' (Gamson 249). Queer identities do not have an explicit place in LCSH. …

Nonattacking Queens in a Rectangular Strip

The function that counts the number of ways to place nonattacking identical chess or fairy chess pieces in a rectangular strip of fixed height and variable width, as a function of the width, is a piecewise polynomial which is eventually a polynomial and whose behavior can be described in some detail. We deduce this by converting the problem to one of counting lattice points outside an affinographic hyperplane arrangement, which Forge and Zaslavsky solved by means of weighted integral gain graphs. We extend their work by developing both generating functions and a detailed analysis of deletion and contraction for weighted integral gain graphs. For chess pieces we find the asymptotic probability that a random configuration is nonattacking, and we obtain exact counts of nonattacking configurations of small numbers of queens, bishops, knights, and nightriders.

The yellow line: a critical study of the symbolic value of artefacts in health care teams

Artefacts reveal an organisation’s “inner life” and they contribute to its image and reputation. They also play a decisive role for an organisation’s development. In this article, similar artefacts from two different health care teams—a trauma team and a psychiatric team—in the same hospital, are compared. The team members were interviewed and their work observed over the course of several years. It was demonstrated that identical pieces of equipment in a trauma team and a psychiatric team signalled opposite values. The psychiatric team was backward-looking, conservative and contradictory. Modern technology and pieces of equipment were associated with an abandoned and previously criticised activity. The corresponding equipment in the trauma team, on the other hand, signalled a forward looking, developing and unified culture. The trauma team was a relatively new and powerfully idealised phenomenon, which attracted attention. The analysis points out how the symbolic values signal that one activity is attractive and pleasing while another has a low external legitimacy.

Legal and ethical consequences of international biobanking from a national perspective: the German BMB-EUCoop project

The international transfer of human biomaterial and data has become a prerequisite for collaborative biomedical research to be successful. However, although a national legal framework for 'biobanking' has already been formulated in many countries, little is known about how an international exchange of data and samples might affect the legal position of national biobanks and their donors. The German Telematics Platform and the Competence Network 'Congenital Heart Defects' jointly instigated a project (BMB-EUCoop) to (i) identify and assess the legal risks ensuing for biobanks and their donors in the context of Europe-wide research collaborations, (ii) devise practical recommendations to minimize or avoid these risks, and (iii) provide generic informational text, contracts and agreements to facilitate their practical implementation. Four different countries were included in the study; namely, the UK, Netherlands, Austria and Switzerland. The results of the study indicate that the degree of similarity between legal systems in different countries varies according to the respective field of jurisdiction. Although personality and property rights have long been enshrined in virtually identical pieces of law, the applicable medical professional regulations were found to be somewhat heterogeneous. Furthermore, clear-cut differences were often found to be lacking between regulations that reflect either 'soft law' or the nationally binding 'hard law' that has emerged from it. In view of the potential ambiguities, the experts uniformly concluded that the rights and interests of national (in this case, German) biobanks and their donors would be best protected by explicitly addressing any uncertainties in formal contractual agreements.

A consensus-based ℓ- Exclusion algorithm for mobile ad hoc networks

This paper addresses the ℓ -Exclusion problem for mobile ad hoc networks. The ℓ -Exclusion problem, a generalization of distributed mutual exclusion problem, involves a group of processes, each of which intermittently requires access to one of ℓ identical resources or pieces of code called the critical section (CS). This paper presents a consensus-based mobility-aware ℓ- Exclusion (LE) algorithm that operates asynchronously and copes explicitly with arbitrary (possibly concurrent) topology changes associated with such networks. The algorithm can tolerate link changes or failures, sudden crashes or recoveries of at most ℓ − 1 mobile nodes. The algorithm is based on collection of enough consensuses for a mobile node intending to enter CS, and uses diffusing computations for this purpose. This paper presents a simulation to demonstrate that the proposed algorithm, as compared to the k-Reverse Link (KRL) algorithm, is quite effective to variety of operating conditions, and is highly adaptive to frequent and unpredictable topology changes due to link changes or failures.

Trash and a New Approach to Cinema Engagé

This paper is an attempt to rethink a new approach to African cinema grounded in the various ramifications of the notion of trash—that is, the materiality of what Ba taille identifies with expenditure: the detritus of the various systems and institu tions engendered by globalized commodity capitalism, and their ultimate relationship to African cinema. In all its senses, the term “trash” impels us to push into the heart of the rubbish tip until we have reached the breaking point where it will then be possible to return to such phenomena as Nigerian video films; to the melodramatic, not only in Nollywood but elsewhere; to the popular and the popularized; to the thematization of the prosthesis as seen in O Heroi; to pieces of identity recuperated in films by Mweze Ngangura; to the poignant effects of African textures and designs in the films of Abderrahmane Sissoko. This supplement to the high forms of “cinema” now functions to destabilize the former systems of culture, and to enable new space-clearing gestures in African film criticism to emerge.

Chemomechanical synchronization in heterogeneous self-oscillating gels

Using computational modeling, we introduce patches of self-oscillating gels undergoing the Belousov-Zhabotinsky (BZ) reaction into a nonreactive polymer network and thereby demonstrate how these BZ gels can be harnessed to impart remarkable functionality to the entire system. By first focusing on two adjacent patches of BZ gels, we show that the patches' oscillations can become synchronized in phase or out of phase, with the oscillation frequency depending on the synchronization mode and the spatial separation between these domains. We then apply these results to an array of five adjacent BZ patches and by varying the distance between these pieces, we dramatically alter the dynamical behavior of the patterned gel. For example, the sample can be made to exhibit a unidirectional traveling wave or display a concerted expansion and contraction, properties that are valuable for creating gel-based devices, such as micropumps and microactuators. The findings point to a "modular" design approach, which can impart different functionality simply by arranging identical pieces of BZ gels into distinct spatial arrangements within a polymer matrix.

2D optical manipulation and assembly of shape-complementary planar microstructures

Optical trapping and manipulation offer great flexibility as a non-contact microassembly tool. Its application to the assembly of microscale building blocks may open new doors for micromachine technology. In this work, we demonstrate all-optical assembly of microscopic puzzle pieces in a fluidic environment using programmable arrays of trapping beams. Identical shape-complimentary pieces are optically fabricated with submicron resolution using two-photon polymerization (2PP) technique. These are efficiently assembled into space-filling tessellations by a multiple-beam optical micromanipulation system. The flexibility of the system allows us to demonstrate both user-interactive and computer-automated modes of serial and parallel assembly of microscale objects with high spatial and angular positioning precision.

Implementing a comprehensive cost information system in rural health facilities: the case of Nouna health district, Burkina Faso

To present first findings of a cost-of-illness (COI) information system implemented in Nouna health district, Burkina Faso. The entire project will include household and provider tangible COI, whereas this article concentrates on the development of a provider cost information system in rural first-line health facilities. Special forms and reports are prepared to routinely collect capital and recurrent costs of first-line facilities. Inventory lists are designed, and buildings and equipment are assessed by engineers. Total, fixed, variable and average costs are calculated for 15 rural health centres with five cost centres: general outpatient consultation, ambulatory nursing care, deliveries, immunization and other services (neonatal consultation, child care and family planning). In 2003, the average costs per service unit were 1.34 US$ for a general consultation, 0.51 US$ for ambulatory nursing care, 6.73 US$ per delivery, 3.64 US$ per vaccination and 1.11 US$ per service unit of other care. On average, a health centre consumes 29,900 US$ per year for a catchment population of 10,000 inhabitants. The major share of costs is fixed and does not depend on the workload of the health centre. Consequently, the costs of first-line facilities will hardly increase if the demand for health services rises. These findings can be used to improve the health financing in Nouna health district, Burkina Faso.

Experimental study for the evaluation of creep in concrete through thermal measurements

This investigation, conducted at the Non-Destructive Testing Laboratory at the Politecnico di Torino, made it possible to establish an experimental relationship between specific creep values measured in concrete test pieces obtained from different mixes and the decrease in temperature observed in identical test pieces at the end of low-intensity short-duration compressive tests. This relationship is independent of type of mix and therefore has general validity: it can be used to make qualitative predictions about creep without having to perform long duration tests. It may lead to interesting developments in various applications, especially in the field of structural diagnosis.

The Last Witness: Testimony and Desire in Zora Neale Hurston's "Barracoon"

Dr. Franz Boas of the Department of Anthropology at Columbia had sent her on her way through the South and instructed her to stop by this man's house. He was said to be the last surviving African brought to the United States as a slave. A relic, a talisman at ninety-five years who could pull the curtain back and reveal the fissure, where the earth cracked, the African perished and the African American emerged. He was an African called Kossula who also went by the slave name Cudjo Lewis. He had been one of 116 African slaves brought to the United States by the Mehears brothers in 1859, on The Clotilde, supposedly the last slave ship. Perhaps one can imagine why she plagiarized. Perhaps the first encounter was a failure. Perhaps it yielded little more than a salutation and a repudiation. Who could blame her? She was young. She was an anthropologist, a scientist. She was an African American woman driving though the South alone in 1928 collecting bits and pieces of African American identity the ephemera, whistles, and

Um refinamento do algoritmo tabu de Dowsland para o problema de carregamento de paletes do produtor

O Problema de Carregamento de Paletes do Produtor consiste em arranjar, ortogonalmente e sem sobreposição, o máximo número de caixas retangulares idênticas de dimensões (l,w) sobre um palete (L,W). Este problema vem sendo tratado com sucesso por heurísticas de blocos, as quais constroem padrões de carregamento com um ou mais blocos, cujas caixas possuem a mesma orientação. Os arranjos gerados por estes métodos estão limitados aos chamados padrões não-guilhotinados de primeira ordem. Neste trabalho, foi elaborada uma implementação baseada no algoritmo de busca tabu de Dowsland, que, ao contrário das heurísticas de blocos, provê arranjos não limitados a padrões particulares de empacotamento. Experimentos computacionais com um conjunto de 34 exemplos extraídos da literatura e de contextos reais indicam que a abordagem é capaz de resolver otimamente a maioria dos exemplos; para os exemplos não resolvidos, é proposto um procedimento adicional simples, cuja aplicação resultou na obtenção de padrões ótimos.

Swapping of three-dimensional domains as a molecular mechanism of dimerization of aminoacyl-tRNA synthetases.

It has been shown recently that many proteins undergo oligomerization through exchange of structural elements. That process, termed a 3D domain swapping, is the replacement of a portion of the tertiary structure of a protein with an identical piece from a second polypeptide chain. When the exchange is reciprocated, domain-swapped dimers embrace with the exchange of elements of secondary structure or domains; however, if the exchange is not reciprocated but propagated along multiple polynucleotide chains, higher-order assemblies may form. In this paper we discuss swapping as a general mechanism of aminoacyl-tRNA synthetases dimerization, specifically plant methionyl-tRNA synthetase.

Gravity on branes

We consider the four-dimensional discontinuity generated by two identical pieces of a five-dimensional space pasted along their edge (that is a ``brane'' in a $``{Z}_{2}$ symmetric'' ``bulk''). Using a four plus one decomposition of the Riemann tensor, we write the equations for gravity on the brane and recover in a simple manner a number of known ``brane world'' scenarios. We study under which conditions these equations reduce, exactly or approximately, to the four-dimensional Einstein equations. We conclude that if the bulk is imposed to be only an Einstein space near the brane, Einstein's equations can be recovered approximately on the brane, but if it is imposed to be strictly anti--de Sitter space then the Einstein equations cannot hold, even approximately, on a quasi-Minkowskian brane, unless matter obeys a very contrived equation of state.