Natural Obstacles Research Articles

New spatial clustering-based models for optimal urban facility location considering geographical obstacles

The problems of facility location and the allo- cation of demand points to facilities are crucial research issues in spatial data analysis and urban planning. It is very important for an organization or governments to best locate its resources and facilities and efficiently manage resources to ensure that all demand points are covered and all the needs are met. Most of the recent studies, which focused on solving facility location problems by performing spatial clustering, have used the Euclidean distance between two points as the dissimilarity function. Natural obstacles, such as mountains and rivers, can have drastic impacts on the distance that needs to be traveled between two geographical locations. While calculating the distance between various supply chain entities (including facilities and demand points), it is necessary to take such obstacles into account to obtain better and more realistic results regarding location- allocation. In this article, new models were presented for location of urban facilities while considering geographical obstacles at the same time. In these models, three new distance functions were proposed. The first function was based on the analysis of shortest path in linear network, which was called SPD function. The other two functions, namely PD and P2D, were based on the algorithms that deal with robot geometry and route-based robot navigation in the presence of obstacles. The models were implemented in ArcGIS Desktop 9.2 software using the visual basic programming language. These models were evaluated using synthetic and real data sets. The overall performance was evaluated based on the sum of distance from demand points to their corresponding facilities. Because of the distance between the demand points and facilities becoming more realistic in the proposed functions, results indicated desired quality of the proposed models in terms of quality of allo- cating points to centers and logistic cost. Obtained results show promising improvements of the allocation, the logis- tics costs and the response time. It can also be inferred from this study that the P2D-based model and the SPD-based model yield similar results in terms of the facility location and the demand allocation. It is noted that the P2D-based model showed better execution time than the SPD-based model. Considering logistic costs, facility location and response time, the P2D-based model was appropriate choice for urban facility location problem considering the geo- graphical obstacles.

On one-dimensional inverse problems arising from polarimetric measurements of nematic liquid crystals

We revisit the problem of determining dielectric parameters in layered nematic liquid crystals from polarimetric measurements originally introduced by Lionheart and Newton. After a detailed analysis of the model, of the scales involved, and of natural obstacles to the reconstruction of more than one dielectric parameters, we produce two simple one-dimensional inverse problems which can be studied without any expertise in liquid crystals. We then confirm that very little can be recovered about the internal configuration of smooth dielectric parameters from these measurements, and give a uniqueness result for one of the two problem, when the unknown parameter satisfies a monotonicity property. In that case, the available data can be expressed in terms of Laplace and Hankel transforms.

Upstream migratory behaviour of wild and ranched Atlantic salmon Salmo salar at a natural obstacle in a coastal spate river

The upstream migratory behaviour of wild and ranched Atlantic salmon Salmo salar in a small Irish coastal spate river was investigated using acoustic telemetry. Prespawning migratory behaviour was investigated including movement patterns at a large natural waterfall in the lower reaches of the river. A strong diurnal pattern was observed for upstream migrants at the waterfall indicative of the need for daylight to ascend this complex natural obstacle to migration. Successful passage of the waterfall was also associated with distinct environmental conditions and no difference in migratory ability was detected between wild and ranched origin S. salar. Wild S. salar tended to exhibit a non-erratic, stepwise upstream migration pattern after ascending the waterfall while ranched S. salar had an increased probability of displaying more erratic migratory behaviour. Wild S. salar penetrated further into the river catchment than ranched S. salar, although male ranched S. salar exhibited the greatest cumulative distance moved prior to the spawning period. The management implications of escaped or released ranched S. salar and movement at natural obstacles are discussed.

Dispersal behaviour of a polygynous carnivore: do cougars Puma concolor follow source‐sink predictions?

The source‐sink model of population dynamics predicts that density drives emigration of subordinate animals to habitats offering lower competition for resources. Several authors have suggested use of this model as a potential framework for conservation of exploited carnivores when precise enumeration is unfeasible. Dispersal is a critical behavioural mechanism for management based on this model, yet there is a lack of knowledge on the habitat and social conditions that motivate carnivore emigration and settlement. The cougar Puma concolor is a widely distributed and heavily exploited carnivore, indigenous to the western hemisphere. We evaluated patterns in cougar dispersal behaviour from two sites in Utah, differing in terms of management and the level of natural and anthropogenic habitat fragmentation. We used our results to evaluate three predictions with respect to cougar dispersal behaviour: 1) natal population density and maternal reproductive status prompt emigration, 2) movement of dispersing cougars is shaped by habitat configuration and permeability, and 3) dispersers preferentially settle in areas of high habitat quality and low conspecific density. We documented the emigration of 62 individuals and measured movement variables, including sex and site‐specific frequency, distance, seasonality, direction and the habitat quality and harvest rates characterizing areas where immigrants settled. Although males and females exhibited pronounced differences in dispersal frequency, we found few differences in distance traveled, season of departure and direction moved. Dispersal occurred most frequently during spring, coinciding with the estrus pulse. Natural and anthropogenic obstacles modified landscape permeability, and therefore dispersal distances were shorter in fragmented habitats than in contiguous ones. Relative to males, females dispersed into habitats of lower productivity with higher mean annual harvest rates. Patterns in male settlement suggested habitat selection based on mating opportunities, whereas female settlement was predicated on avoiding conspecifics. Cougars in this Great Basin ecosystem largely conformed to source‐sink predictions. Results can be used to parameterize source‐sink models based on animal behaviour and landscape permeability to conserve exploited carnivores, under conditions of population expansion or recolonization of habitats where Allee effects are a limiting factor.

Conserved versatile master regulators in signalling pathways in response to stress in plants.

From the first land plants to the complex gymnosperms and angiosperms of today, environmental conditions have forced plants to develop molecular strategies to surpass natural obstacles to growth and proliferation, and these genetic gains have been transmitted to the following generations. In this long natural process, novel and elaborate mechanisms have evolved to enable plants to cope with environmental limitations. Elements in many signalling cascades enable plants to sense different, multiple and simultaneous ambient cues. A group of versatile master regulators of gene expression control plant responses to stressing conditions. For crop breeding purposes, the task is to determine how to activate these key regulators to enable accurate and optimal reactions to common stresses. In this review, we discuss how plants sense biotic and abiotic stresses, how and which master regulators are implied in the responses to these stresses, their evolution in the life kingdoms, and the domains in these proteins that interact with other factors to lead to a proper and efficient plant response.

Los invernáculos de José María Samper: utopías espaciales fuera y dentro del trópico

Nineteenth-century creole Colombians described the national tropical space as utterly divided by mountains into different climates and distinct races. The coming to power of young Laissez Faire liberals in mid-nineteenth-century Colombia—José María Samper being their most fervent ideologue—would not entail debunking this image, but problematically refashioning it to fit a cosmopolitan paradigm of a boundless territory in which Europe and Colombia could be connected by commerce. The European Winter Garden is a space where Samper refashions the national space. It is an enclosed place where tropical vegetation can be captured and transformed into pure capital by controlling its climate and ridding it of those natural obstacles and races that are considered (by Samper) fragmentary preludes to civilization. Fantasizing about the tropics as a place without history and without people (of color), in his visits to European winter gardens Samper tries to turn the Colombian lowlands into a fetish, deactivating its threatening nature. Thus winter gardens can be interpreted as places to gaze into a dystopian world—vegetative spaces, the aftermath of cultural genocide in the Colombian tropics.

Transcription-replication encounters, consequences and genomic instability

To ensure accurate duplication of genetic material, the replication fork must overcome numerous natural obstacles on its way, including transcription complexes engaged along the same template. Here we review the various levels of interdependence between transcription and replication processes and how different types of encounters between RNA- and DNA-polymerase complexes may result in clashes of those machineries on the DNA template and thus increase genomic instability. In addition, we summarize strategies evolved in bacteria and eukaryotes to minimize the consequences of collisions, including R-loop formation and topological stresses.

Yeast competence for exogenous DNA uptake: towards understanding its genetic component

The demonstration of spontaneous yeast competence shows that artificial transformation rests on naturally occurring cellular processes. Such natural competence is either biologically mediated or environmentally induced. For instance, wild yeast might be transformed through conjugation by cell-to-cell contact mediated either by Escherichia coli or Agrobacterium tumefaciens. Moreover, natural competence can be enhanced by mechanical and physiological mechanisms. On the other hand, artificial yeast competence is usually achieved by biological, chemical and physical manipulations. These eliminate or weaken natural obstacles blocking the way of the transforming DNA in order to mitigate its entrance into the cell (biological and chemical approach) or simply to bridge it by either electrical or biolistic force (physical). Thus yeast competence is controlled by intrinsic (genetic) and external (environmental) factors. Both intrinsic and external parameters affecting yeast competence were scrutinized leading to the identification of genes and biological processes participating in the phenomenon. Therefore natural yeast competence is a complex, quantitative genetic trait which may have allowed yeast to better adapt over evolutionary times.

Performance assessment of GPS/GLONASS single point positioning in an urban environment

In signal-degraded environments such as urban canyons and mountainous area, many GNSS signals are either blocked or strongly degraded by natural and artificial obstacles. In such scenarios standalone GPS is often unable to guarantee a continuous and accurate positioning due to lack (or the poor quality) of signals. The combination of different GNSSs could be a suitable approach to fill this gap, because the multi-constellation system guarantees an improved satellite availability compared to standalone GPS, thus providing enhanced accuracy, continuity and integrity of the positioning. The present GNSSs are GPS, GLONASS, Galileo and Beidou, but the latter two are still in the development phase. In this work GPS/GLONASS systems are combined for single point positioning and their performance are assessed for different configurations. Using GPS/GLONASS multi-constellation implies the addition of an additional unknown, i.e. the intersystem time scale offset, which requires a sacrifice of one measurement. Since the intersystem offset is quasi-constant over a short period, a pseudo-measurement can be introduced to compensate the sacrifice. The benefit after adding a pseudo-measurement has been demonstrated in a vehicular test.

中国农业转型中地方模式的比较研究

Abstract The development of markets and the penetration of capital into agriculture have started the agrarian transition in rural China, which is transforming smallholding, household-based agriculture into various forms of capitalistic production. This again raises in a new historical and social context the long-debated question in the agrarian transition literature: Can family farms survive the onslaught of capitalist agriculture based on wage labor and what shapes the confrontation between family farms and agro-capital? I argue that it is the local political economy—rather than some natural obstacles in agriculture to the penetration of capitalism—that shapes this confrontation and gives rise to a variety of local patterns in how family producers interact with agro-capital. Conceptually, the primary dimension in which local patterns diverge is how direct producers’ transactions with the product market are mediated. Based on this distinction, I identify three distinct local paths of agrarian transition—agribusiness-led corporate production, independent household production, and cooperative production. I use data collected from fieldwork and secondary sources to show how, in each model, characteristics of the local pattern are shaped by the local political economy. (This article is in English.) 摘要 市场的发展与资本的进入引发了中国的农业转型, 将小规模的家庭农业转变成各种形式的资本化农业。这在一个新的历史与社会背景中重新提出了农业转型研究中一个长期辩论的课题: 在资本化农业的冲击下, 家庭农业能否继续生存? 什么因素塑造家庭农场与农业资本之间的对抗? 本文提出, 是地方的政治经济, 而不是农业生产中某些能阻止资本扩张的天然障碍, 在塑造这种对抗, 并产生出一系列家庭生产者与农业资本之间互动的模式。这些模式间的差异首先来自于直接生产者是如何与产品市场对接。我根据此区分出三种农业转型的地方性路径: 企业带动的公司化生产、农户的独立生产、和合作化生产。我以实证资料来展示, 在每个模式中, 地方的政治经济如何塑造这一模式的特点。

Formação da Cidade de Belém (PA): Área Central e seu Papel Histórico e Geográfico

Belém teve em um promontório localizado no vértice da baía do Guajará e dorio Guamá no século XVII seu ponto irradiador da vida urbana, o qual teve em alguns “obstáculos naturais” (cursos d'água e áreas de várzea e igapós) empecilhos momentâneos para desenvolver-se com plenitude. Superados os obstáculos, a cidade de Belém expandiu-se tendo em sua área central expressões de mudanças e permanências. Logo, torna-se interessante identificar e analisar as alterações histórico-geográficas na área central de Belém para entender o processo de refuncionalização ocorrente nesta área e suas novas funcionalidades refletidas no espaço urbano.

PLANIALTIMETRIC ACCURACY EVALUATION OF DIGITAL SURFACE MODEL (DSM) AND DIGITAL TERRAIN MODEL (DTM) OBTAINED FROM AERIAL SURVEY WITH LIDAR

Abstract. It’s noticed a significant increase in the development of orbital and airborne sensors that enable the extraction of three-dimensional data. Consequently, it's important the increment of studies about the quality of altimetric values derived from these sensors to verify if the improvements implemented in the acquisition of data may influence the results. In this context, as part of a larger project that aims to evaluate the accuracy of various sensors, this work aims to analysis the planialtimetric accuracy of DSM and DTM generated from an aerial survey with LIDAR, using as reference for the planimetric analysis of the orthophotos obtained. The project was developed for an area of São Sebastião city, located in the basin of the North Coast of São Paulo state. The area's relief is very steep, with a predominance of dense forest vegetation, typical of the Atlantic Forest. All points have been established in the field, with the use of GNSS of one frequency (L1) through static relative positioning, acquiring a minimum of 1,500 epochs, for a distance less than 20 km to the base. In this work it's considered the Brazilian standard specifications for classification of cartographic bases (PEC). The Brazilian company responsible for the aerial survey (LACTEC) gave the following products for analysis: point clouds in raw format (x, y, z) using orthometric heights; point clouds (first and last pulse) for each range of flight to verify systematic errors; DTM uniformly spaced, filtering small natural obstacles, buildings and vegetation, in Geotiff format; DSM also uniformly spaced, in Geotiff format; and the mosaic of georeferenced digital images. The analysis realized on products from the LIDAR indicated their adoption to the scales 1:2,000 (Class A for the orthophotos and Class B for the DTM) and 1:5,000 (class C for the DSM). There were no indications of trends in the results. The average error was 0.01 m. It's important that new areas with different topographic characteristics may be evaluated to get an indication for other situations. As to the assessment of the altimetric accuracy, we are going to do more analysis with points obtained under the forest canopy in order to be able to assess the real accuracy of the DTM in areas with forest cover. Studies that focus the development of new methodologies for obtaining Digital Elevation Models (DEM) are very important, especially in large scales, seeking to generate data with cost-benefit's advantages. This way, topographic features can be obtained for wider areas of our country, meeting the needs of most studies and activities related to the representation of these kind of data.

Brown Trout Spawning Migration in Fragmented Central European Headwaters: Effect of Isolation by Artificial Obstacles and the Moon Phase

AbstractThe spawning migrations of 123 brown troutSalmo truttawere studied in six highland streams in the Elbe River catchment area, Czech Republic, in central Europe. Trout were observed by using radiotelemetry from August to November in headwater stretches isolated by artificial obstacles without fish ladders. The length of isolated headwater stretches ranged between 5.7 and 16.1 km. Migration distance per day and total migration length over the study period (total migration) were analyzed. In total, 1,957 individual fish positions were recorded. In general, the brown trout spawning migration reflected the seasonality with respect to temperature. Migration distance per day was low in August, reached a maximum in October, and then decreased in November. In isolated headwaters, trout adapted their migrations to the length of available free migration stretches, as both migration descriptors (migration distance per day and total migration) increased according to this variable. Moon phase appeared to be the key factor that influenced the timing of brown trout migration activity on a daily basis. High migration distance per day occurred during the eclipse of the moon, whereas the lowest migration distance per day occurred during the full moon. Furthermore, migration distance per day decreased with increasing river slope. The other variables tested (sex and physicochemical parameters, such as flow, pH, conductivity, and dissolved oxygen) did not affect brown trout migration activity. The results indicated that despite the restrictions of upstream migrations by lateral obstacles without fish ladders, brown trout migration activity in artificially isolated headwaters with pristine morphology is preserved. Furthermore, the analyses revealed a significant impact of the moon phase on brown trout migration that has not been previously described for this species. Although the observed migration occurred over a short period of time, brown trout did not adopt sedentary behavior, as has been described in the river stretches upstream from natural obstacles, such as waterfalls.

Microwave Path Survey Using Differential GPS

A microwave path survey is critical before any wireless communication infrastructure can be put into place. It is on the basis of this that the line of sight possibility between any pair of stations is established. This survey can also be used to determine whether there is sufficient space available on existing telecommunication towers, where additional telecommunication facilities can be hosted. This study has demonstrated that differential GPS techniques can successfully be used in microwave path surveys within the framework of telegeoinformatics. The adopted methodology simulated a levelling circuit for the defined observation network. This resulted in an acceptable misclosure of 0.039m which was distributed among the various stations in proportion to the relative length of each link. Natural and man-made obstacles (critical points) along the various telecommunication links were also determined.

Analysis Of Heart Rate And Hematologic Changes During An Adventure Race

Adventure race is a sport practiced in direct contact with nature, in which the athlete transposes natural obstacles (rivers, mountains, forests) through different sports (trekking, mountain bike, rowing, vertical techniques, and others). Despite its growth and visibility, there are few studies that examined the acute physiological adaptations during adventure races. PURPOSE: The aim of this study was to record the physiological intensity during adventure sprint race as well as analyze the hematological parameters of the participants before and immediately after the competition. METHODS: The heart rate of seven male athletes (27.7±5.9 years, 63.2±3.68 kg body weight, 170.2±3.47cm in height, 6.91±1.75% body fat and VO2 peak of 60.84±1.81 mLO2.kg-1.min-1) was monitored during an adventure race comprising the types: trekking, mountain bike and vertical techniques (total distance of 42.1 km). Blood samples were collected 24 hours before the race and immediately after arrival. RESULTS: The average length of race was 4h38min52s, with a predominance of the intensity zone above 85% HR reserve. There were a reduction in blood cells, hemoglobin and mean corpuscular volume, and an increase in leukocytes immediately after the finish compared to 24hs prior the race. CONCLUSION: We conclude that the predominance of intensity zone above 85% of reserve heart rate associated with hematological changes characterize this type of competition as high intensity. However, the various possible combinations of an adventure race (course, modalities, distance and duration) should be considered for training and to define strategies during the race.Supported by FAPEMIG and CNPq.

SKYPLOT_DEM: a tool for GNSS planning and simulations

Satellite survey techniques have become com- monplace for several applications such as surveying, environmental positioning, and navigation. The possibility of using this technique is strongly dependent on the possibility of receiving data from at least four satellites, as the accuracy is dependent on both the number of visible satellites and on their relative positions in the sky. From a theoretical standpoint, the Global Positioning System (GPS) constellation of satellites was designed to guarantee the continuous visibility of a minimum of four satellites worldwide, but this was based on the major approximation of considering the earth as an ellipsoid. The presence of natural (such as mountains) and anthropic (such as buildings) obstacles reduce sky visibility, in some cases significantly, thereby reducing the position accuracy or the possibility of determining a position (in the case of less than four satellites). The evolution of satellite positioning technologies will result in the possibility that, in the near future, many constellations can be used to determine the position of a receiver. Additionally, the Glonass constella- tion will be improved, and the new Galileo constellation will be deployed. Starting from digital elevation models (DEM), orbits (broadcast or precise), and the Keplerian parameters of new constellations, an open-source software has been realized with the aim of performing more accurate planning and simulations of the skyplot (the map of the visible satellites) in a point or region for a defined window of time. The software, developed in the C++ language, permits the simulation of the current constellation and the simulation of future scenarios by considering the interop- erability between NAVSTAR-GPS, GLONASS, Galileo, COMPASS, and other systems. The simulation, conducted using DEM, permits the definition of a more correct obstacle map for each point. Of course, the DEM is more detailed and accurate, resulting in a more precise obstacle map and thus a more precise simulation (DEMs derived from Lidar data can even be used to account for the blockage caused by buildings). This paper begins with an introduction concerning the approach used to determine the skyplot and the obstacle map derived from a DEM, continues by explaining the logical architecture of the software and then presents simulation results in different conditions (with or without the DEM, using different constellations, and considering either one point or a regional analysis).

Planning and design of ecological networks in urban areas

Urban ecological networks are defined differently in ecology, urban planning and landscape ecology, but they all have linearity and linkage in common. Early urban representations evolved from the constraints of deep ecological structure in the landscape to built elements that must work around natural linear obstacles—rivers, coastlines, dunes, cliffs, hills and valley swamps. Village commons were linked by roads. The Industrial Revolution led to accelerating urban growth, where the role of open space focussed on public health and transport. The Renaissance, Baroque and Picturesque movements accentuated networks in wooded parks, boulevards and sweeping riverine vistas. These provided a new aesthetic and sense of grandeur in the urban centres of European empires and later their colonies. Grafted onto this visual connectivity has been an awakened ecological understanding of spatial dynamics. The emergent notion of ecological corridor functionality provided support for green linear features, although initially this was based on untested theory. The idea of organisms moving along green highways seemed logical, but only recently has unequivocal empirical evidence emerged that demonstrates this functionality. Nevertheless, the main role of corridors may be to provide habitat rather than to act as connectors of nodal habitats. Most organisms can utilise stepping stones, and these may accommodate desired meta-populations while deterring pest movement. Swale drains and treatment wetlands provide riparian services and serve as biodiversity corridors. However, to most people the obvious function is visual—providing green fingers through what would otherwise be urban grey. The health benefits of these are have been demonstrated to be psychological as much as biophysical.

Efforts in the State of Qatar to conserve and monitor endangered marine turtles

Abstract Marine turtles are listed as endangered and they belong to Animal Kingdom phylum Chordata, class Reptilia and are descendants from early reptiles. Marine turtles are long-living and the females lay many eggs. Each year, thousands of hatchlings emerge from their nests along many coastlines across the world. Natural obstacles faced by young and adult sea turtles are numerous and on the increase, including natural predators and human exploitation. Unfortunately, only an estimated one in 1000 to 10000 will survive to adulthood. Together with marine biologists at Qatar University, studies on marine turtles in the State of Qatar were initiated in 2002, sponsored by Ras Laffan Industrial City. The outcome of the 2002 study provided the baseline data needed for subsequent studies. It has now been established that only one species of the endangered extant marine turtles, the Hawksbill turtle, nests in the Gulf area and in Qatar along the northeastern sandy beaches and islands (Ras Laffan, Fewairit, Al Maronah, Al Ghariyah, Jazirat Ras Rakan, Jazirat Umm Al Tays and Halul Island). Studies showed that Ras Laffan City is a major nesting area [No. of nests recorded since 2001: (2001: 74), (2002: 240), (2003:208), (2004: 190), (2005: 229), (2006:129), (2007:76), (2009: 72)]. An outcome of the studies since 2002 showed that females average clutch size varies between 65-78 eggs, which are incubated for 51-57 days in a nest temperature of 28.6⁰C – 33.3⁰C. Since 2009, efforts to monitor the nesting population along the Qatar coastline have started and the satellite tracking of females continues. This showed the females remain in the Gulf waters between Ras Laffan moving north (Kingdom Bahrain – Kingdom of Saudi Arabia) and south to the UAE. One tracked female travelled a maximum distance of 1917 km in 147 days. A number of females have been tagged to date, of which 3 tagged in 2005 returned to nest in 2009. Between 2009 and 2010 over 40 females were tagged.

Shoestring Soldiers: The 1st Canadian Division at War, 1914–1915 (review)

Reviewed by: Shoestring Soldiers: The 1st Canadian Division at War, 1914–1915 Stephanie Cousineau Shoestring Soldiers: The 1st Canadian Division at War, 1914–1915. Andrew Iarocci. Toronto: University of Toronto Press, 2008. Pp. 384, $50.00 Andrew Iarocci's Shoestring Soldiers: The 1st Canadian Division at War, 1914–1915 is aptly described by its title. It examines the first year of the 1st Canadian Division in the First World War, through which Iarocci aims to challenge the old thesis explaining the Canadian Division's performance with the notion that it suffered material deficiencies – not training and experience deficiencies – and was thus fighting on a 'shoestring.' The book is developed from Iarocci's dissertation and joins a small number of books looking at how the Canadians fought the Great War. More specifically, outside of A.F. Duiguid's and G.W.L. Nicholson's official histories of 1938 and 1962 respectively, there has been a silence in operational histories of the Canadians at war. This silence has been answered in part quite recently with the small flurry of similarly focused books, including Kenneth Radley's We Lead, Others Follow: First Canadian Division, 1914–1918 (2006) and Tim Cook's At the Sharp End (2007). This speaks directly to the need for revised assessments of Canada's combat role in the First World War; Iarocci's part in that is to offer a fresh perspective on previously trod ground. Shoestring Soldiers is very much an operational history, exploring the first year of Canada's war in five phases: the four months of training in Britain; deployment to Armentières, Belgium; the gassing of Entente troops at Ypres; reinforcement and redeployment to Festubert and Givenchy; and finally, the 'lull' of active defence at Ploegsteert. [End Page 778] Iarocci's skills in battlefield history are illustrated in the telling of these stories, interspersed with vignettes of soldiers' experiences for a personal touch. Still, making such operational studies truly relevant and far-reaching remains a significant challenge. On the first, the author is more successful than the second: his thesis is valid and well founded, and has been taken up by other historians (namely Tim Cook in the above-mentioned text). It is therefore more the pity that it is developed in the denseness of operational terms, because even the numerous maps, photographs, and interludes of human interest do not make this an easily accessible study. Iarocci makes a plausible case in framing his argument, and even in suggesting how his main point has been overlooked in other studies. The traditional perspective on the significance of the First World War in Canadian history is that it served as a turning point in the state's development: Canada went to war tied to Britain's war effort but came out of it seeking greater autonomy within the empire, specifically in foreign, diplomatic, and military affairs. Iarocci moves beyond this 'colony-to-nation' focus, though arriving at his conclusion by using roughly the same sources. This could be either a strength or a weakness: on the one hand, it suggests the beneficial effect of returning to previously used documents with new eyes, from which the relatively small field of Canadian history has not always benefited. On the other hand, it risks being seen as 'old wine in new bottles.' The latter is likely too harsh, ultimately, for Iarocci is clear in his introduction that he has considered the myriad factors that contributed to the 1st Canadian Division's operational successes and failures, and agrees with the 'Canadians-as-shock-troops' perspective as the end point of the Canadian Corps' abilities. It is only in looking at the causes and consequences of the road to shock-troop status that he finds a new conclusion, which demonstrates that this is not just a new angle for a new angle's sake. Shoestring Soldiers is at its best when Iarocci integrates descriptions of terrain and geography into the battle narrative; one perhaps best understands battles after having walked the ground in question to see just what natural obstacles stood in the way of – or amplified – the chances of battlefield success. Iarocci brings foreign fields to life for the readers, capitalizing...

Procedural Generation of Roads

AbstractIn this paper, we propose an automatic method for generating roads based on a weighted anisotropic shortest path algorithm. Given an input scene, we automatically create a path connecting an initial and a final point. The trajectory of the road minimizes a cost function that takes into account the different parameters of the scene including the slope of the terrain, natural obstacles such as rivers, lakes, mountains and forests. The road is generated by excavating the terrain along the path and instantiating generic parameterized models.