Spatial Point Of View Research Articles

The Anisotropic Lagrangian Averaged Euler and Navier-Stokes Equations

The purpose of this paper is twofold. First, we give a derivation of the Lagrangian averaged Euler (LAE-α) and Navier-Stokes (LANS-α) equations. This theory involves a spatial scale α and the equations are designed to accurately capture the dynamics of the Euler and Navier-Stokes equations at length scales larger than α, while averaging the motion at scales smaller than α. The derivation involves an averaging procedure that combines ideas from both the material (Lagrangian) and spatial (Eulerian) viewpoints. This framework allows the use of a variant of G. I. Taylor's turbulence hypothesis as the foundation for the model equations; more precisely, the derivation is based on the strong physical assumption that fluctutations are frozen into the mean flow. In this article, we use this hypothesis to derive the averaged Lagrangian for the theory, and all the terms up to and including order α^2 are accounted for. The equations come in both an isotropic and anisotropic version. The anisotropic equations are a coupled system of PDEs (partial differential equations) for the mean velocity field and the Lagrangian covariance tensor. In earlier works by Foias, Holm & Titi [10], and ourselves [16], an analysis of the isotropic equations has been given. In the second part of this paper, we establish local in time well-posedness of the anisotropic LANS-α equations using quasilinear PDE type methods.

Projets de grande vitesse ferroviaire en Grande-Bretagne : lignes ou réseau ?

Great Britain, with a rail network disadvantaged by half a century of underinvestment, is about to introduce high speed trains. A first project, using tilting trains on the major rail link of the country between London, Manchester and Glasgow, is based on a deep modernisation of the existing infrastructures. The other project consists in building a new line between London and the Channel tunnel, that extends the European high speed rail network. Nevertheless, these improvements were not obtained through exclusive private funds as the government expected it in privatising the rail system, and the slow modernisation occurs with heavy public subsidies. From a spatial point of view, the new high speed rail line, introducing new connexions at the national and international but also regional scales, contributes to a recomposition of the Great Britain's rail geography.

L'image de l'espace scolaire dans les livres de lecture de l'école primaire, Buenos Aires 1853‐1942*

This paper seeks to throw new light on an important source for the History of Education, the Reading school book. Within a larger research project we are carrying out on formation of primary schools in the city of Buenos Aires, the Reading book has surfaced as a key documentary source. Our point is that the Argentine Nation State needed an architectonic dimension in configuring its primary school, a dimension that used readings and images that were distinct from material resources that traditionally signified national importance. In brief, Argentina had to turn the primary school into a place easily recognizable for what happens inside ‐ teaching and learning ‐ and for what that teaching and learning stood for. the Nation‐State in its capital city. Reading books took on an important role in this nation buildingprocess, through both iconographie and textual materials that conveyed various ways of imagining school space, especially a poetic sense of space which signified multiple modes of representation and assertion. The most interesting aspect in the paper is its use of the spatial viewpoint, along side of the material aspect of school buildings. The words and images printed in Reading books, their variance and dominance, go beyond the material and evoke the sense and meaning of space in a broader sociohistorical framework. * Traduction française de Lucia Inés Dorín et Maria Sol Dorin. Pour cet article le prix ISCHE‐2000 a été décerné à l'auteur.

Enhancing Mobility Behavior Analysis Using Spatial Interactive Tools and Computer Intensive Methods

Since several decades, French urbanization evolves in a way that can hardly be seen favorable to public transportation. Innovation is needed in this field, if the individual automobile is to be faced on its own territories. This need for innovation concerns the miscellaneous stages of the public transport production, including the preliminary analysis ones. Indeed, many work remains to be done to understand mobility behavior, what is more if we are to propose versatile and viable alternatives to current trends. The aim of this paper is to underline the relevance of exploratory spatial analysis strategies in a context of operational research. As a spatial phenomenon, mobility might be studied from a spatial point of view. Interactive visual analysis is a simple but powerful way of analyzing complex information. Moreover, desegregated but still synthetic approaches have to be privileged. Then, local numeric indicators are found to be much more useful than global ones. An example of such a strategy, led using the statistical package Xlisp-Stat, is exposed below, so as to support these assertions.

From Land Cover to Land Use: A Methodology for Efficient Land Use Mapping over Large Areas

Land use information over large areas is increasingly important for many studies related to environment in general and global change in particular. Yet there is a dearth of methodological knowledge in this area, especially regarding the practical task of producing land use maps. In this article, a systematic land use mapping approach is developed, based on land cover maps that in turn are produced through remote sensing. The concept is based on the recognition of varying strengths of land cover (LC) – land use (LU) relationships, from the thematic and spatial points of view. Several categories of relationships are identified, ranging from direct (case 1) to multiple/complex (case 4), and appropriate mapping strategies are discussed for these cases. Using a mapping study in Lebanon, it is shown that the principles embodied in this approach correspond to issues and conditions in real mapping situations. Finally, the concepts are translated into a series of steps through which the method can be applied to large areas, taking into consideration the specific requirements and constraints of each case. The final land use map represents an acceptable compromise between accuracy, level of detail, and cost.

From Land Cover to Land Use: A Methodology for Efficient Land Use Mapping over Large Areas

Land use information over large areas is increasingly important for many studies related to environment in general and global change in particular. Yet there is a dearth of methodological knowledge in this area, especially regarding the practical task of producing land use maps. In this article, a systematic land use mapping approach is developed, based on land cover maps that in turn are produced through remote sensing. The concept is based on the recognition of varying strengths of land cover (LC) – land use (LU) relationships, from the thematic and spatial points of view. Several categories of relationships are identified, ranging from direct (case 1) to multiple/complex (case 4), and appropriate mapping strategies are discussed for these cases. Using a mapping study in Lebanon, it is shown that the principles embodied in this approach correspond to issues and conditions in real mapping situations. Finally, the concepts are translated into a series of steps through which the method can be applied to large areas, taking into consideration the specific requirements and constraints of each case. The final land use map represents an acceptable compromise between accuracy, level of detail, and cost.

Temporal and spatial use of stranded wrack by the macrofauna of a tropical sandy beach

During two field studies the macrofauna associated with wrack stranded on a tropical sandy shore was analysed. During the first period all animals present in small wrack deposits were randomly collected with cores. During the second field study active animals were sampled in larger wrack deposits for an entire lunar period, and tube traps were used. After a comparison between the two studies, only the data from the tube traps were examined from a temporal and spatial point of view. The aim of the present work was to gain information on how, when and where wrack was colonised by invertebrates, keeping in mind cyclical aspects such as lunar, diel and tidal phases. Predatory taxa, such as Staphylinoidea and the amphipods Talorchestia martensii, were most abundant, whereas Diptera larvae and Tenebrionidae were scarce. Successional changes of beach wrack colonisation were evident throughout a semi-lunar period, with molluscs invading wrack during the first days of deposition and histerids during the last ones. Strictly nocturnal or diurnal surface-active species were found to be active in the wrack during both the day and the night. The analysis of the tidal component of species activity in the wrack showed that some species moved at ebbing tide, and others moved at rising tide. Differences were found also in the mean hours of tidal activity, calculated separately during day and night periods. The study of the zonation of each species showed that in some cases wrack deposits were closely followed by the fauna as their position changed during the semi-lunar phase. In other cases differences occurred between species zonation during day and night periods and tidal phases. Cluster analysis indicates that most species exploit the wrack in different ways (as refuges and/or feeding site), both in space and in time.

An orphic journey to the disorient: Salman Rushdie's The ground beneath her feet

This article argues that Salman Rushdie's The Ground Beneath Her Feet is not so much a planetary novel as a creative passage to America. It aims to study how the author connects East and West by using the concept of metamorphosis to explain the mutation of identity after the end of empires. It explores the novel's theme of disorientation from personal, spatial, temporal, ideological and representational points of view and concludes that the disconcertingly filmic mode in which it is written bears witness to Rushdie's belief in the capacity of the cinema to save the novel from its fin de siècle crisis.

Mortalité de l'huître Crassostrea gigas dans le bassin de Marennes-Oléron: étude de la variabilité spatiale de son environnement et de sa biologie par un système d'informations géographiques (SIG)

The summer mortality patterns was studied in 1996 on the Ronce-les-Bains oyster bank (175 ha), located on the southern part of the Bay Marennes-Oléron (Atlantic coastline). Studies on growth, sexual maturation, survival rates and environmental variables were compared at fifteen experimental sites (on- and off-bottom culture). After 7 months, cumulative mortality reached 8–19 and 23–33 % for off-bottom and on-bottom culture, respectively, which is significantly higher for the latter case. A seasonal mortality trend was noted, with a significant increase related to air temperature greater than 20 °C and with a significant pre-spawning glycogen catabolism. Based on soft tissue flesh growth results from both types of culture, several empirical models were developed to assess overall yield from a spatial point of view. A N-NW positive trend was noted for the soft tissue flesh, suggesting a decrease in food availability towards the southern part of the bay. Yields (total weight) ranged from 85 to 2 % for off-bottom cultures with 25 and 50 % emersion times, respectively. For on-bottom culture, several sites have shown a negative yield down to −10 % in the southern oyster bank sites. The highest yields were noted in areas located on the E-NE part of the Ronce oyster bank.

Temporal and spatial elements of thermocapillary convection in floating zones

We investigated experimentally spatio-temporal convective flow phenomena in cylindrical liquid bridges [floating-(half-)zones] of liquids with different Prandtl-numbers (NaNO3?Pr=7; C24H50?Pr=49; C36H74?Pr=65). The convective flow is driven by thermocapillary forces (TC-forces) and buoyancy forces. The zones were heated from above (ΔT, Ma>0) or from below (ΔT, Ma<0) to couple both effects in different ways. Optical evaluations (view from above and view from the front) in connection with thermocouple (tc) measurements (tc-tips distributed over one half of the free surface) made it possible to get very new ideas of spatio-temporal flow structures in the considered convective system. In this article we deal with some transitionary temporal phenomena accompanying the system’s way to chaotic behaviour. We present results supplementary to well-known transitions to chaos (i.e. quasi-periodic and period-doubled flow states) and introduce some very special events. Here all considerations are based on a primarily “temporal way of thinking”. We then try to illuminate several flow situations primarily from a more “spatial point of view”. Possible spatio-temporal convective flow structures are discussed by accompanying the system from a laminar flow state up to the onset of chaotic motion. Starting with former ideas of spatio-temporal flow situations we recognize 2D- and 3D-stationary flows, “pulsating” and “rotating” modes m=1 and 2, different spatial reasons for quasi-periodic and period-doubled temporal behaviour and different spatial mechanisms that cause spatio-temporal chaotic structures in the system considered. One should realize the ambiguity of a certain time-signal with respect to various spatial structures. Additionally we find out that a revision of the interpretation of very complicated Ma/Ma c (A)-state maps now becomes necessary. These state maps show the present flow state (e.g. a time-dependent, quasi-periodic or chaotic one) depending on the geometrical parameter aspect ratio A (i.e. the zone length) and the TC-force (i.e. the Marangoni-number).

Leaf Anatomy of Patchouli (Pogostemon patchouli) with Reference to the Disposition of Mesophyll Glands.

Two groups of secretory glands, epidermal and mesophyll types, were examined in the young leaves of patchouli plants with light and electron microscopes. The structural characteristics of the component cells and features of the neighboring cells were clarified at the cyto-histological aspect. Glandular trichomes originate from both the adaxial and abaxial epidermis. Considerable attention is focused on internal, mesophyll glands arising in the palisade tissue. The secretory cell of the mesophyll glands is covered by a cuticular layer, and secretory materials are collected in a subcuticular space made between the cuticle and wall materials. In the vicinity of the glands, a vascular system occurs in spongy parenchyma. It includes vessel elements, sieve elements, large-sized cells of vascular bundle Sheath and morphologically specialized idioblasts; among them, relatively small sized-cells are present. The idioblasts have highly branched plasmodesmata in the wall and numerous mitochondria in the cytoplasm, but are lacking in a large, central vacuole. The branched plasmodesmata occur in groups. They intrude into the walls of sieve elements running in the interior of the vascular bundles and also into the walls of enlarged cells forming the bundle sheath. From a spatial viewpoint, it is likely that the vascular system has a relation to the transfer of nutrients into the mesophyll glands from the surrounding cells with photosynthetic activities. On the basis of these observations, the peculiar morphology of the mesophyll glands is discussed in terrns of their location and function in patchouli leaf blades.

Intercomparison of spatial and temporal variability of various precipitation estimates

Four precipitation estimates were intercompared from their spatial and temporal variability point of view. Two of the products are observational based and the other two are model based assimilation products. An EOF analysis technique was applied to decompose the data into various temporal and spatial modes. All four show similar spatial structure on annual and interannual time scales over continental regions, but differences exist over oceanic regions and observational based products show larger amplitudes. The first three EOF modes together explain 49.4% of the variance.

Normalization under conflict? Spatial and demographic changes of Arabs in Haifa, 1948–92

The purpose of this article is to examine...changes and indicate the emerging trends among the Arab population [in Haifa Israel] and within its residential areas. The first section will explain the development of the residential spatial pattern of Haifas Arabs as it took shape until the 1970s.... The changes themselves will be described separately from both the demographic and spatial point of view in the second part of the article. (EXCERPT)

Woman's Theatrical Space, and: Theatre and Feminist Aesthetics (review)

Reviewed by: Woman’s Theatrical Space, and: Theatre and Feminist Aesthetics Susan C. Haedicke Woman’s Theatrical Space. By Hanna Scolnicov. Cambridge: Cambridge University Press, 1994; pp. 177. $49.95 cloth. Theatre and Feminist Aesthetics. Edited by Karen Laughlin and Catherine Schuler. Madison: Fairleigh Dickinson University Press, 1995; pp. 319. $45.00 cloth. These two books exploring women and theatre could not be more different. Woman’s Theatrical Space examines the gradual dissociation of woman and home in major plays from the Greeks to the present day and the parallel shift in attitudes towards the woman’s familial role. Theatre and Feminist Aesthetics, on the other hand, offers a collection of essays “focusing on theatre as a forum for feminist redefinitions of the aesthetic” (17). Yet this unlikely pairing of works together offers an interesting dialogue on the position of women in today’s cultural landscape and on feminist scholarship in the academy. In a comparative study of a sampling of plays from Aeschylus to Pinter, Beckett, and Handke, Hanna Scolnicov sets out to establish that “the ideological positions of the society and of the playwright shape the contours of the theatrical space. . . . [And that] the analysis of theatrical space directly reveals the changing conceptions of woman’s position in the family and in society” (8). In order to do so, she distinguishes between “theatrical space within” (spaces visible to the audience) and “theatrical space without” (off-stage or invisible spaces). Scolnicov admits that the division of within and without is most easily recognizable in the opposition of indoors and outdoors, and she, somewhat conveniently, chooses to limit her discussion almost exclusively to plays in which this dichotomy represents such a pairing. She justifies this choice by asserting that structural division of space into the interior and the exterior of the house carries with it social and cultural implications. Gender roles are spatially defined in relation to the inside and the outside of [End Page 398] the house. Traditionally, it is the woman who makes the house into a home, her home, while the world of commerce, war, travel, the world outside, is a man’s world. . . . From the spatial point of view, the world of the man and the world of the woman meet on the threshold. [6] The argument which follows traces the shift in “theatrical space within” from exterior scenes to interior ones and finally to abstract spaces devoid of gender signification. This development, for Scolnicov, parallels the gradual “dissolution of woman’s unique bond with space” (155), her loss of identification with the home. Beginning with Aeschylus, Scolnicov explores the significance of the skene as the wall between the outdoors and the indoors, the visual manifestation of the incipient tradition of dividing space into gender specific areas. She shows how, in Agamemnon, the skene represents the threshold of the palace separating the public and ceremonial area of the returning warriors from the domestic world of the women left behind. Thus Agamemnon’s crossing of that threshold, the central action of the play, visually manifests the conflict of genders. Architecturally, the skene represents the border between indoors and outdoors, but conceptually, Scolnicov asserts, it reflects the division between man’s and woman’s world. Scolnicov develops subsequent chapters using a similar methodology. Throughout the book, she explores how “woman’s special links with space, based on her privileged position in the home” (154) gradually shrink and disappear. Moliere marks the revolutionary shift from exterior to interior spaces being presented on stage, a shift which signifies the invasion of woman’s space and the start of her gradually shrinking connection with it. By Beckett, space is no longer gender-specific as Winnie’s mound in Happy Days or the disembodied mouth in Not I epitomize. More compelling than the survey of the gradual dissociation of woman and home in western drama are the parallels Scolnicov establishes at certain times in the book between space and the woman’s body. In her analysis of Lysistrata, for example, she shows how the theatrical space becomes eroticized through its association with the female body which, in turn, endows every action with sexual overtones. The Acropolis, the interior space claimed by the...

Comparison of routing algorithms for digital elevation models and their implications for predicting ephemeral gullies

ABSTRACT Six routing algorithms, describing how flow (and water borne material) will be routed over Digital Elevation Models, are described and compared. The performance of these algorithms is determined based on both the calculation of the contributing area and the prediction of ephemeral gullies. Three groups of routing algorithms could be identified. Both from a statistical and a spatial viewpoint these groups produce significantly different results, with a major distinction between single flow and multiple flow algorithms. Single flow algorithms cannot accommodate divergent flow and are very sensitive to small errors. Therefore, they are not acceptable for hillslopes. The flux decomposition algorithm, proposed here, seems to be preferable to other multiple flow algorithms as it is mathematically straightforward, needs only up to two neighbours and yields more realistic results for drainage lines. The implications of the routing algorithms on the prediction of ephemeral gullies seem to be somewhat counterintuitive: the single flow algorithms that, at first sight, seem to mimic the process of overland flow, do not yield optimal prediction results.

Assessing cellular proliferation: what's worth measuring?

The assessment of cellular proliferation is, in the main, carried out on histological material. Ideally, such methods should be applicable to routinely processed tissues, they should be relatively inexpensive and the results easily quantified and interpreted. A knowledge of what is 'normal' within the tissue from both a temporal and spatial point of view is essential. There is a burgeoning literature on novel markers of cell proliferation, usually these are immunohistochemically based, each method with its own unique set of conditions for optimal tissue processing. Some would argue this is simply a process of 'reinventing the wheel' since mitotic counting is a perfectly adequate indicator of proliferation, but we could justly counter that a labelling index (S-phase or growth fraction) is more likely to produce an accurate assessment when the sample size is small. In tumours, tissue heterogeneity is likely to render any single measurement meaningless. To date, there are no reliable validated immunohistochemical markers of the labelling index in animal tissues which visualise naturally occurring proliferation-associated molecules, though this may change shortly.

Varsovie, les changements contemporains d'une métropole d'Europe de l'Est (Warsaw, current changes within an eastern European Metropolis)

Abstract. - In 1989, the disappearance of communism in Poland put Warsaw on the privatization and free market economy feet. This sweeping change is built up around the following patterns : actors competing for space use, shift to local self-government by communes, transformation of labour market. From a spatial point of view, these changes are going on with a transformation of urban landscape and with the setting of discrepancies between neighborhoods. Within the political map of the New Europe, the chief point is to know into what urban network will Warsaw fit.

The Spatial Diffusion of Riots: Popular Disturbances in England and Wales, 1750–1850

The form taken by the spatial diffusion of rioting offers valuable clues for the understanding of collective protest. Careful analyses of the space and time dimensions of collective protest reveal considerable variation with respect to the cause of the riot, the role of communications and accessibility, and the agency of radical leaders and state and local authorities. Some historians have failed to understand this. Even Wells who has been sympathetic to the potential of the spatial viewpoint in explaining popular disturbances has written of food riots in 1801 that “(r)iots spread. It is immaterial whether the cause was imitation, or a uniform reaction along lines of communication‘. Stevenson has gone further and written in the context of food rioting that “it is misleading to speak of riots spreading’. Both take a narrow, rather over simplified, position, particularly when discussing waves of concerted collective action. Such occurrences are rare and provide us with one of those “privileged instances which one can apprehend on the level of observation when the totality of society and its institutions is set in motion’. They present us with an opportunity to begin to identify those peculiar conditions under which massive mobilisation of people in different communities takes place. In this essay I consider several case studies of the spatial diffusion of disturbances in England and Wales between 1750 and 1850. These protests differ dramatically in their patterns of spatial diffusion.

Seguridad ciudadana: reflexiones y pistas a seguir

This paper collects some of the ideas presented at the "V Taller de Coyuntura" as well as ideas by authors who have worked on this topic from a spatial viewpoint. The importance of urban an architectural intervention as prevention strategies is here stressed. The paper such strategies can be produced, the institutional structure and in a few words the city and the society we are building as potenciations of delinquency and citizen's insecurity. Finally, it proposes several actions to face this problem to reinforce civil society as an element of prevention, to potenciale the collective production of space, to re-value local space as a prevention place and give way for an institutional structure which would promote the co-responsibility for public space, all within a global plan to face the problem.

The Linear Spatial-Temporal Interaction Process and its Relation to 1/ω-Noise

SUMMARY If we are to gain an understanding of the evolutionary processes which generate pattern then time cannot be ignored, since a purely spatial viewpoint disregards the fundamental generating mechanism of the underlying process. We therefore develop a spectral approach based on a general growth–interaction model; individuals grow at intrinsic rate λ, while two individuals a distance r apart interact at rate ar times their size difference. Special cases considered involve nearest neighbour, geometric, logarithmic and Cauchy-type dependence. A separate study is made of ‘long-term persistence‘; an autoregressive binomial weight structure is used to generate processes with power law spectra ωd. We examine the effect of arranging the general process on a ring of N sites, and then use this structure to simulate nearest neighbour and binomial interaction.