Territory Shape Research Articles

Physical tethering and volume exclusion determine higher-order genome organization in budding yeast

In this paper we show that tethering of heterochromatic regions to nuclear landmarks and random encounters of chromosomes in the confined nuclear volume are sufficient to explain the higher-order organization of the budding yeast genome. We have quantitatively characterized the contact patterns and nuclear territories that emerge when chromosomes are allowed to behave as constrained but otherwise randomly configured flexible polymer chains in the nucleus. Remarkably, this constrained random encounter model explains in a statistical manner the experimental hallmarks of the S. cerevisiae genome organization, including (1) the folding patterns of individual chromosomes; (2) the highly enriched interactions between specific chromatin regions and chromosomes; (3) the emergence, shape, and position of gene territories; (4) the mean distances between pairs of telomeres; and (5) even the co-location of functionally related gene loci, including early replication start sites and tRNA genes. Therefore, most aspects of the yeast genome organization can be explained without calling on biochemically mediated chromatin interactions. Such interactions may modulate the pre-existing propensity for co-localization but seem not to be the cause for the observed higher-order organization. The fact that geometrical constraints alone yield a highly organized genome structure, on which different functional elements are specifically distributed, has strong implications for the folding principles of the genome and the evolution of its function.

Foraging Habitat Distributions Affect Territory Size and Shape in the Tuamotu Kingfisher

I studied factors influencing territory configuration in the Tuamotu kingfisher (Todiramphus gambieri). Radiotelemetry data were used to define territory boundaries, and I tested for effects on territory size and shape of landscape habitat composition and foraging patch configuration. Tuamotu kingfisher territories were larger in areas with reduced densities of coconut plantation foraging habitat, and territories were less circular in the study site that had a single slender patch of foraging habitat. Maximum territory length did not differ between study sites, however, which suggested that the size of Tuamotu kingfisher territories might be bounded by the combined influence of maximum travel distances and habitat configurations. Results also suggested that birds enlarge territories as they age. Together, results supported previous work indicating that territory configurations represent a balance between the costs of defending a territory and gains from territory ownership.

Who Sprawls Most? Exploring the Patterns of Urban Growth across 26 European Countries

In recent years considerable progress has been made in the understanding of urban land-use change and its dynamic interrelationships with economic, social, and environmental systems. From a quantitative perspective, advancements in GIS technologies, the increased availability of high-resolution remote sensing data, and new GIS-based spatial metrics of urban form and urban growth have helped to establish methods for comparative spatial analysis. However, due to the lack of homogeneous data, very few empirical studies have systematically addressed urbanisation and urban growth at a cross-national level. With this background, this paper presents a comparative assessment of urban land-use change across twenty-six European countries. On two scales of analysis, country and 20 km cells, we found a surprising variability in terms of urban growth and its territorial shape. We argue that these differences cannot be explained by varying demographic or economic growth pressures alone. Indicators on the composition, pattern, and density of urban growth illustrate that country-specific drivers of urban land-use change play an important role for the shaping of Europe's settlement structure.

Shape of Single and Multiple Central-Place Territories in a Stream-Dwelling Fish

Territory shape yields important insights into how animals exploit local resources. Territories of stream-dwelling salmonids are typically (1) mapped around a single central-place, (2) described as circular, elliptical or teardrop-shaped, and (3) believed to reflect their exploitation of drifting invertebrate prey. In this study, we tested the current view of territory shape by mapping multiple central-place territories for 50 young-of-the-year Atlantic salmon. Multiple central-place areas were more elongated (eccentricity: median = 1.301, range = 1.043–2.784) than the foraging patterns around each central place (eccentricity: median = 1.135, range = 1.014–1.385). In addition, multiple central-place areas were elongated along the stream length (33 of 50 fish), whereas the foraging areas around each station tended to be elongated along the stream width (32 of 50 fish). These findings may be explained by the way that stream salmonids interact with drifting prey. At each central place, a wider foraging area should provide an increased access to prey drifting downstream. Similarly, by regularly patrolling a large multiple central-place area along the stream axis, a territorial fish may increase its access to drifting prey by excluding competitors from upstream areas. Further studies are needed on the ecological factors that determine territory shape in stream fish and multiple central-place foragers.

3D Reconstruction of the Poggio Sommavilla Territory (Sabina Tiberina, Rieti- Italy) A new approach to the knowledge of the archeological evidences

<p>The area object of this paper is located in the Middle Tiber Valley and comprises a wide stretch of land within the loop of the river Tiber between the municipalities of Magliano Sabina and Ponzano. A study about this region was published in the volume 44 of the Series Forma Italiae, as it has played an important role in the reconstruction of the cultural and historical aspects of the Sabine Tiber Valley in ancient time. Its geological structure has produced a characteristic wavy landscape wich has determined the country life from time to time. Therefore, the 3D reconstruction of this area appears an important aid to the knowledge of the territory shape and its evolution. In fact the 3D model of this area has been developed in order to better understand its geological, hydrographical and anthropological conformation.</p>

Out of Sight, Out of Mind? Visual Obstructions Affect Settlement Patterns in Barn Swallows (Hirundo Rustica)

ABSTRACT. Neighbor visibility is thought to influence territory size and shape, and visual obstructions may allow for greater nesting density within a breeding colony. We studied the effects of neighbor visibility and neighbor proximity on settlement patterns in a colony of Barn Swallows (Hirundo rustica) using artificial nest cups placed in parallel rows on the underside of a pier. Nest cups were placed 61 cm apart so that the distance between adjacent cups matched the distance between adjacent rows. Rows were separated by the vertical panels to which the nest cups were attached. To a swallow perched on a cup, cups in the same row were visible but cups in adjacent rows were visually obstructed. We compared the observed nest-settlement patterns with expected distributions generated both by calculating cup availability and by simulating random settlement events. Barn Swallows avoided settling 61 cm from an active nest only if that neighbor was visible; visually obstructed neighbors at the same distance wer...

Ciência, fronteiras e nação: comissões brasileiras na demarcação dos limites territoriais entre Brasil e Bolívia, 1895-1901

O artigo trata de três expedições brasileiras à Amazônia Ocidental que tiveram por missão demarcar os limites entre Brasil e Bolívia nos anos 1895-1901. O objetivo é apreender o papel que a ciência desempenhou em uma negociação que contribuiu para que o Brasil tivesse as feições territoriais da atualidade. O artigo procura abordar, sob o ponto de vista da história da ciência, um tema tradicionalmente estudado pelo viés da geopolítica, ou seja, a formação das fronteiras internacionais, evidenciando uma intercessão entre institucionalização da ciência e formação da nação.

Structure and dynamics of interphase chromosomes.

During interphase chromosomes decondense, but fluorescent in situ hybridization experiments reveal the existence of distinct territories occupied by individual chromosomes inside the nuclei of most eukaryotic cells. We use computer simulations to show that the existence and stability of territories is a kinetic effect that can be explained without invoking an underlying nuclear scaffold or protein-mediated interactions between DNA sequences. In particular, we show that the experimentally observed territory shapes and spatial distances between marked chromosome sites for human, Drosophila, and budding yeast chromosomes can be reproduced by a parameter-free minimal model of decondensing chromosomes. Our results suggest that the observed interphase structure and dynamics are due to generic polymer effects: confined Brownian motion conserving the local topological state of long chain molecules and segregation of mutually unentangled chains due to topological constraints.

Territory characteristics and coexistence with heterospecifics in the Dartford warbler Sylvia undata across a habitat gradient

The study of successional gradients may help to understand the relative influence of habitat structure and competition on territory characteristics. Here, we evaluate the effects of vegetation cover, conspecific and heterospecific densities, and distance to the nearest neighbor on territory size, shape, and overlap in insectivorous birds. We studied these effects along a gradient of postfire habitat regeneration in which foliage cover and densities of focal species varied several-fold. We delineate 197 territories (minimum convex polygons) of the shrub-dwelling Dartford warbler (Sylvia undata) and 255 of the syntopic Sardinian (Sylvia melanocephala), subalpine (Sylvia cantillans) and melodious (Hippolais polyglotta) warblers at three plots in NE Catalonia (Spain and France) in 1987–2005. After accounting for the effect of the number of locations used to delineate polygons, generalized linear mixed models (GLMM) showed a reduction in territory area of the Dartford warbler as conspecific density increased and distance to nearest neighbor decreased, in accordance with the contender pressure hypothesis for territory size regulation. Heterospecific density was not included in the final model of territory size and the effect of habitat structure was marginal. Territory roundness was positively correlated with its size and with conspecific density, probably in relation to energetic constraints, and negatively with heterospecific density. Territorial exclusion was almost complete among Dartford warblers, whereas interspecific territory overlap was extensive and tended to increase with heterospecific density and with structural diversity along the gradient. Our results support the hypothesis that Mediterranean warbler coexistence derives from ecological segregation and not from interspecific territoriality.

SPATIAL FORMATION OF MOHALLA IN VARANASI CITY (UTTAR PRADESH, INDIA)

This paper focuses upon the spatial formation of mohalla in Varanasi city. Mohalla is traditional neighborhood unit common in North Indian cities, and it was the elemental component of the city in Mughal period as an administrative tax unit as well as an autonomous organization. Nowadays, however, it has lost the administrative meaning and its geographical extent and boundary are becoming unclear.Based on our field survey, this paper clarifies the spatial formation of mohalla such as allocation, size, boundary form, distribution of facilities and street structure, and links them to the historical formation process of the city. The mohallas of Varanasi can be classified broadly into two types. One has linear or tree shape formed along streets, and the other has broad territorial shape. The spatial features of those two types are different in various aspects, in reflection of the degree of urbanization at the time the mohallas were established.

Effects of patch shape and group size on the effectiveness of defence by juvenile convict cichlids

The causes and consequences of territory size have attracted considerable attention, but there has been relatively little research on optimal territory shape. We manipulated the shape of food patches, independent of patch area (square, 13.6 × 13.6 cm; rectangular, 46.5 × 4.0 cm; elongated, 93.0 × 2.0 cm), presented to small, medium and large convict cichlids, Archocentrus nigrofasciatus , in groups of varying size (three, six, 12 fish). We used a 3 × 3 factorial design to test the predictions that the defence and monopolization of a food patch would decrease as both patch perimeter and group size increased. As predicted, with increasing patch perimeter, the ability of the large (dominant) fish to defend the patch decreased, as reflected by a decrease in the frequency of aggression and the proportion of the aggression by the dominant. Similarly, intruder success typically increased with increasing patch perimeter, as reflected by an increase in the proportion of intruders in the patch and the duration that an intruder remained in the patch. Group size also had the predicted effect on most response variables; in general, defender success decreased and intruder success increased as group size increased. Furthermore, the effects of increasing the patch perimeter and group size on measures of defensibility were largely additive.

Shape of territories in some competing growth models

We study two competing growth models. Each of these models describes the spread of a finite number of infections on a graph. Each infection evolves like an (oriented or unoriented) first passage percolation process except that once a vertex is infected by type $i$ infection, it remains of type $i$ forever. We give results about the shape of the area ultimately infected by the different infections.

Modeling and field-testing of Ovenbird (Seiurus aurocapillus) responses to boreal forest dissection by energy sector development at multiple spatial scales

Although the area disturbed by linear features in forested systems is small relative to many other human disturbances, linear features create significantly more amounts of edge per unit area. In the boreal plains of Alberta, Canada, energy sector exploration has resulted in extensive dissection of the landscape through 8 m wide seismic lines. A spatially explicit model was developed to test how bird abundance might change in response to increasing seismic line density if individuals use seismic lines as territory boundaries or actively avoid these edges. Assuming birds had fixed territory shape and size, increasing seismic line density from 0 to 8 km/km2 resulted in a 38% decline and an 82% decline in bird abundance when individuals used lines as territory boundaries or avoided edges by 50 m, respectively. We tested the assumptions of our model using the Ovenbird (Seiurus aurocapillus). Based on radio-telemetry (n = 12), all Ovenbirds crossed seismic lines at some point during the breeding season. However, male Ovenbirds showed a distinct use of one side of the seismic line, suggesting lines acted as territory boundaries. In 12.25 ha plots (n = 24) spot-mapping detected no change in Ovenbird density as linear feature density increased from 0 to 8.6 km/km2. In 4 km2 landscapes (n = 62) sampled using a grid of nine point-counts, we also detected no changes in Ovenbird numbers across the same range of seismic line densities. Ovenbirds declined with seismic line density at the level of the individual point-count station (12 ha scale), but only when a threshold seismic line density of 8.5 km/km2 was reached. Above the threshold, Ovenbirds declined 19% for each 1 km/km2 increase in seismic line density. While relatively few places in Alberta’s boreal forest have local seismic line densities of 8.5 km/km2, forest dissection could increasingly become an issue if current energy exploration practices continue.

Une industrie nouvelle en zone rurale : de la fabrique d’une main-d’oeuvre à la fabrique de destins sociaux territorialisés ?

The setting up of a new sector plant in a rural district : beyond the construction of a new local workforce, a territorial shaping of social trajectories The setting up of a new sector plant in a rural district automatically induces new patterns of labor categories and residential space according to the type of housing provided. If we examine these patterns over time, we can observe that they change because of the changing social properties of new generations of actors. But the way social actors perceive these patterns often doesn’t change. It seems that for them the points of reference they use to decide about action are permanent, stable and anchored in their territory. This article focuses on this perception of territory and is based on field research in a district around a new nuclear plant. We examine in detail a special family history that reveals actors’ normal – but normally invisible – attachment to reference marks anchored in territory : in this family, the intergenerational reproduction of social position was only possible because the son left the area, which was extremely painful for the parents. Their suffering was not due merely to a sence of betrayal with respect to a paternalist firm struggling to assure employment for the new generation. Nor was it a matter of deep territorial anchorage of the family, broken by economic restructuring. It seems rather that it was their sense of positive or negative social destiny, which was mediated by their ties with the territory. So we can speak about a territorial shaping of social trajectories.

Regional spaces, spaces of regionalism: territory, insurgent politics and the English question

Amid the globalization of economic life and a myriad of powerful challenges to Westphalian traditions of political statehood, it is now routinely contended that regions are ‘in resurgence’. Nonetheless, much of the debate on this purported regional renaissance is bedevilled by confusion over what scholars and activists mean by regions and an analogous mystification as to why some regions are ‘successful’, ‘lagging’ or ‘different’. Our paper aims to instil some coherence to this debate by distinguishing between what we term regional spaces and spaces of regionalism. It then draws on this distinction to explore the institutionalization of England's South West region, highlighting some tensions which prevail over its economic future, its political representation, its territorial shape and cultural vernacular. In undertaking this, we demonstrate how the formation of any given regional map is reflective – and indeed constitutive – of an unevenly developing, often overlapping and superimposing mosaic of economic practices, political mobilizations, cultural performances and institutional accomplishments. This prompts us to question the currently fashionable inclination to fully jettison a scalar and/or territorial approach to the theory and practice of spatiality in favour of relational/topological/non‐territorial approaches.

Social justice and the region: grassroots regional movements and the ‘English Question’

This paper is positioned within debates on the territorial restructuring of the national state and the emergence of regions as new spaces for instilling economic and social governance. It is argued that the rescaling of state capacities and competences associated with the programme of economic devolution in England—set within a broader context of state restructuring in the UK through constitutional change—is providing an emerging cultural and political territorial space in and through which grassroots social justice movements are attempting to gain popular support. The highly uneven and fragmented nature of English regional identity and interest‐group formation is acknowledged and a distinction is drawn between state‐driven and (top–down) functional regionalisation and (bottom–up) civil society regionalism to explore this. Discussion then focuses on how regionalisation in the East Midlands is being contested by the regionalists Devolve! (known from 1988–2000 by their former name Movement for Middle England). The paper shows how Devolve! has struggled to gain support and, as sole regional pressure group, is being drawn into the bargaining process, spearheaded by the central state, concerning how the regional process, particularly its ‘territorial shape’, could be defined. Reflections on the theory and practice of politics and spatiality in geography and especially the recent interest in relational space conclude the paper.

Song variation and environmental auditory masking in the grasshopper sparrow

Some grassland bird species, in particular grasshopper sparrows (Ammodramus savannarum), sing songs with especially high mean frequencies (7.0–8.0 kHz). Acoustic interference is one potential explanation for the evolution of high frequency vocalizations, particularly in open habitats. We tested predictions from a model of effective auditory communication distances to understand the potential effects of vocal production and environmental auditory masking on vocal behavior and territoriality. Variation in the spectral structure of songs and the size and shape of territories was measured for grasshopper sparrows in typical grassland habitats. Median territory areas were 1629 m2 at a site in the center of the species range in Nebraska, and 1466 m2 at our study site in Maryland, with average territory diameters measuring 20.2 m. Species densities and sound pressure levels also were determined for stridulating insects and other noise sources in the habitat. Based on current models of effective communication distances, known noise levels, and information on hearing abilities, our results suggest that auditory sensitivity and environmental noise could be factors influencing the mean frequency and spatial dynamics of territorial behavior in grassland birds. [Work supported by NIH and the CRFRC.]

Oil policies and privatization strategies in Mexico: implications for the petrochemical sector and its production spaces

Through a retrospective analysis of Mexico's oil history, this work examines the privatization processes that occurred in the petrochemical sector, from the abolishment of the government's monopoly, Petróleos Mexicanos (PEMEX) during the 1980s, until the restructuring and open liberalization in the early 1990s, focusing on the areas incorporated to production processes, particularly along the Gulf coast. As a result of the industrial policies and regional development strategies promoted by the government from the sixties, oriented towards strengthening production in areas with the highest potential, attractive business investment areas were developed. These included southern Tamaulipas, a strategic region where a number of industrial factors facilitated access to raw materials at competitive prices, as well as their processing and distribution to local and international markets, all of these within a single location. The strategic nature of the petrochemical location and production have made southern Tamaulipas a key factor for the territorial shaping and industrial development linked to the behavior of transnational companies that, seeking comparative advantages, have relocated parts of their production capacity in this region.

National Home/Personal Home: Public Housing and the Shaping of National Space in Israel

The massive investment in public housing for immigrants in the early years of the State of Israel has usually been presented in terms of the achievements in modernization and absorption of immigrants. A closer look at the State agenda reveals the dual role of public housing--the shaping of territory and the shaping of identity. This article provides a critical view of the hegemonic practice of the State in its formative years, in which the location, planning, design, population and administration of these housing estates were carried out. The aim of the article is not to challenge the achievements of housing in the nation-building process, but to provide some new dimensions for consideration in the analytic discourse of housing in general. A critical definition of public housing that goes beyond the usual portrayal as public good is presented. This is seen in the context of the physical shaping of national space, or the spatialization of territory, whereby the State via the ideologically conscripted professionals used public housing as a tool to mould new immigrants into loyal citizens of an imagined nation-state. The resulting peculiar physical/cultural landscape, which persists to this day, is associated with a large marginalized and excluded social group: the Mizrachi population. Several crucial questions concerning the future of these public housing estates are raised and the prospects of their transformation into meaningful living places within the dialectics of spatial production by the State are questioned.

Optical metropolitan DWDM networks an overview

The paper deals with the subject of how to build a core network in the current technology scenario. We start with an overview ofwhat we consider a core network, not in an abstract way but referring to real country situations, and pointing out the differentaspects conditioning its realisation – population distribution, territory shape, traffic characteristics. In the next section asummary of different network topologies is presented and briefly analysed – rings, meshes, loosely or tightly interconnected,with particular attention to the resilience aspect in case of faults. The following section is dedicated to a short presentation of thecurrent technology scenario and how it reflects on the network elements (NEs) offered on the market (OXC, OADM, PXC, etc).Finally, the question is posed: “What is the best way to implement a core network?” with the conclusion being that there is nosingle answer – each situation must be pursued on a case-by-case basis.This paper describes some important aspects of next-generation metropolitan networking, with special focus on market driversand applications, upcoming standards like GFP and GMPLS, required functionalities like optical switching and protection, and ageneric view on a next-generation platform.