Natural Obstacles Research Articles

Killing The Greatest Killer—Smallpox

Killing The Greatest Killer—Smallpox

Differential regulation of homologous recombination at DNA breaks and replication forks by the Mrc1 branch of the S-phase checkpoint

The Rad52 pathway has a central function in the recombinational repair of chromosome breaks and in the recovery from replication stress. Tolerance to replication stress also depends on the Mec1 kinase, which activates the DNA replication checkpoint in an Mrc1-dependent manner in response to fork arrest. Although the Mec1 and Rad52 pathways are initiated by the same single-strand DNA (ssDNA) intermediate, their interplay at stalled forks remains largely unexplored. Here, we show that the replication checkpoint suppresses the formation of Rad52 foci in an Mrc1-dependent manner and prevents homologous recombination (HR) at chromosome breaks induced by the HO endonuclease. This repression operates at least in part by impeding resection of DNA ends, which is essential to generate 3' ssDNA tails, the primary substrate of HR. Interestingly, we also observed that the Mec1 pathway does not prevent recombination at stalled forks, presumably because they already contain ssDNA. Taken together, these data indicate that the DNA replication checkpoint suppresses genomic instability in S phase by blocking recombination at chromosome breaks and permitting helpful recombination at stalled forks.

Spatio-Temporal Modelling of Dust Transport over Surface Mining Areas and Neighbouring Residential Zones.

Projects focusing on spatio-temporal modelling of the living environment need to manage a wide range of terrain measurements, existing spatial data, time series, results of spatial analysis and inputs/outputs from numerical simulations. Thus, GISs are often used to manage data from remote sensors, to provide advanced spatial analysis and to integrate numerical models. In order to demonstrate the integration of spatial data, time series and methods in the framework of the GIS, we present a case study focused on the modelling of dust transport over a surface coal mining area, exploring spatial data from 3D laser scanners, GPS measurements, aerial images, time series of meteorological observations, inputs/outputs form numerical models and existing geographic resources. To achieve this, digital terrain models, layers including GPS thematic mapping, and scenes with simulation of wind flows are created to visualize and interpret coal dust transport over the mine area and a neighbouring residential zone. A temporary coal storage and sorting site, located near the residential zone, is one of the dominant sources of emissions. Using numerical simulations, the possible effects of wind flows are observed over the surface, modified by natural objects and man-made obstacles. The coal dust drifts with the wind in the direction of the residential zone and is partially deposited in this area. The simultaneous display of the digital map layers together with the location of the dominant emission source, wind flows and protected areas enables a risk assessment of the dust deposition in the area of interest to be performed. In order to obtain a more accurate simulation of wind flows over the temporary storage and sorting site, 3D laser scanning and GPS thematic mapping are used to create a more detailed digital terrain model. Thus, visualization of wind flows over the area of interest combined with 3D map layers enables the exploration of the processes of coal dust deposition at a local scale. In general, this project could be used as a template for dust-transport modelling which couples spatial data focused on the construction of digital terrain models and thematic mapping with data generated by numerical simulations based on Reynolds averaged Navier-Stokes equations.

NATURE IN ARISTOTLE'S ETHICS AND POLITICS

Aristotle's doctrine that human beings are political animals is, in part, an empirical thesis, and posits an inclination to enter into cooperative relationships, even apart from the instrumental benefits of doing so. Aristotle's insight is that human cooperation rests on a non-rational propensity to trust even strangers, when conditions are favorable. Turning to broader questions about the role of nature in human development, I situate Aristotle's attitude towards our natural propensities between two extremes: he rejects both the view that we must bow to whatever nature dictates, and also the view that nature is generally or always to be suppressed or overcome. This middle position requires that Aristotle hold nature and goodness apart, so that the latter can serve as a standard for evaluating the former. He holds that nature does not treat all human beings alike: just as some are handicapped in their development by a deficiency in their natural abilities or propensities, others are extraordinarily fortunate and have so powerful a disposition to act well that they easily acquire good habits and skills of practical reasoning. Further, he recognizes that sociable inclinations and natural virtues have to compete in the human soul with other natural forces that make ethical life extraordinarily difficult. That is why things so often go so badly for us: we need not only to subdue the external environment, but to overcome certain inner natural obstacles as well. Even so, for Aristotle ethical life is not generally alienated from nature, as it is for other philosophers.

P483 Effects of sleep deprivation plus physical exercise in breathing during polysomnographic of adventure racers athletes after a race

Introduction: Adventure race is a sport where the athletes has to complete several km distributed in different sporty modalities, faced natural obstacles and sleep deprivation (SD). In November of 2005, Rio Grande do Sul (RS, Brazil) hosted Ecomotion-Pro, the most important ‘‘non-stop’’ and challenging adventure race on the Brazilian calendar that consisted in 6 nights and 7 days. Objective: The purpose of this study was to investigate the breathing and sleep pattern in athletes after ECOMOTION-PRO 2005. Methods: Seven athletes of both genders were volunteers in this study, standard polysomnographic recordings (Rechatscaffen & Kales, 1968), were carried out using an Embla Digital A10 Recording/amplifier with Somnologica software (Flaga h.f., Reykjavik, Iceland), one week before the race and at first sleep after the race. The athletes performed the race that consisted in 444 km distributed in different sports modalities (trekking, rappel, mountain biking, canoeing, ascension and rafting) and they slept only 3 hours in 6 days. Results: After the race was observed a significative decreased of sleep latency (15.04 ± 9.75 to 2.00 ± 3.01); of stage 2 NREM (59.44 ± 6.01 to 48.78 ± 6.29) and increased of total sleep time (403.96 ± 46.46 to 711.16 ± 192.83); delta sleep (15.92 ± 4.75 to 24.56 ± 6.30); AHI (1.06 ± 0.92 to 4.86 ± 2.08); Hypopnea (0.76 ± 0.96 to 4.38 ± 1.93) and number of breathing events (7.80 ± 5.97 to 54.80 ± 25.85). Conclusion: These data suggest that changes in breathing and sleep patterns of adventures racers after a race is directly correlated with total sleep deprivation and volume of exercise. Acknowledgement:

Acquiring “Knowledge of Our Own Continent”: Geopolitics, Science, and Jeffersonian Geography, 1783–1803

In his role as a promoter of scientific exploration of North America, Thomas Jefferson shared with Jedidiah Morse, considered by many to be the father of American geography, the patriotic desire to counteract misinformation furnished by “imperfect and erroneous sketches” describing the continent's geography by European writers. Yet his interest in the science of geography was also motivated by a concern with America's self-image in the realm of international politics, learning, and commerce. In the summer of 1802 Jefferson was prompted to send an exploring party to North America's westernmost territories in response to reading Voyages from Montreal, Alexander Mackenzie's account of his voyages across the continent to its northwest coast. At the end of his narrative, the Scottish explorer had encouraged Britain's control of a region that, if certain natural obstacles were overcome, might supply fur and fish to “the markets of the four quarters of the globe,” and proposed a line of fortified posts to be established to maintain the British Empire's presence from Lake Winnipeg to the Pacific. Jefferson understood that such action would obstruct America's westward expansion, block Russian advances from Alaska, and thus make possible a British dominion linking two great oceans. Edward Thornton, the British minister to the United States, would later observe that Mackenzie's discoveries had provoked the American President, who in 1803 was also the president of the American Philosophical Society, to concretize his dream “to set on foot an expedition entirely of a scientific nature for exploring the Western continent of America,” and that he was, furthermore, “ambitious in his character of a man of letters and science, of distinguishing his Presidency by a discovery” of a route to the Pacific Ocean by way of the Missouri, “now the only one left to his enterprise, the Northern Communication having been so ably explored and ascertained by Sir Alexander Mackenzie's journeys.

Great Britain and Her Efforts for the Establishment and Maintenance of the European Commission of the Danube (1855-1858)

The paper analyses the position of the British diplomats regarding the question of establishing a regime of free navigation on the maritime sector of the Danube. As the economic interests of English or French merchants, eager to conquer the grain commerce of the Romanian Principalities, were threatened at the Lower Danube by natural or artificial obstacles tolerated by the Russian authorities, the Sulina controversy was among the great international litigations that European diplomats wished to solve in the context of the Crimean War. During the Conference of Vienna (1855) and at the Congress of Paris (1856), debates around the international regime of the Danube were very complicated. The British representatives, acting in common with their French colleagues, fought for the establishment of a European Commission of the Danube, an international committee whose mission was to improve the conditions of navigation at the mouths of the river. The Eastern Empires, Russia and Austria, were opposing this initiative of the Maritime Powers, which endangered their own economic supremacy in the region. Thus, the initial success of establishing the European Commission had to followed by intensive efforts in order to make this body as solid and efficient as possible.

Travel time as a predictor of linguistic distance

The aim of the present investigation 1 was to get an impression of the geographic influences on the dialectal variation in a country. In previous investigations, the correlations between linguistic distances and geographic distances using dialect data from the Netherlands and Norway were calculated (Gooskens and Heeringa 2004, Nerbonne et al. 1996). The results showed a high correlation in the case of Dutch data while the correlation was considerably lower in the case of Norwegian data. This seems to reflect the fact that especially for Norway the direct distance between two settlements does not reflect the difficulty of travel and therefore social contact, which is expected to play a role in keeping linguistic distance within limits. Holland is a country with a flat, regularly populated landscape with few natural obstacles such as mountains and rivers. This is in great contrast with Norway with its high mountains and many fjords which made it quite difficult to travel between places, especially in the past. These differences in geographical situations are clearly reflected in the correlations between the linguistic and geographical distances between the dialects of the two countries. The present investigation is searching for more successful ways of predicting linguistic distances by means of geographic distances in Norway. To this end, old and new traveling data were used providing information about traveling times by road, train, and boat between the places where the different dialects are spoken. The results show that a large part of the linguistic variation can be accounted for by geography in Norway, just as in the Netherlands. However, in the case of a geographically more compli

Robust position-based routing for wireless ad hoc networks

We consider a wireless ad hoc network composed of a set of wireless nodes distributed in a two dimensional plane. Several routing protocols based on the positions of the mobile hosts have been proposed in the literature. A typical assumption in these protocols is that all wireless nodes have uniform transmission regions modeled by unit disk centered at each wireless node. However, all these protocols are likely to fail if the transmission ranges of the mobile hosts vary due to natural or man-made obstacles or weather conditions. These protocols may fail because either some connections that are used by routing protocols do not exist, which effectively results in disconnecting the network, or the use of some connections causes livelocks. In this paper, we describe a robust routing protocol that tolerates up to roughly 40% of variation in the transmission ranges of the mobile hosts. More precisely, our protocol guarantees message delivery in a connected ad hoc network whenever the ratio of the maximum transmission range to the minimum transmission range is at most 2 .

The sky as a topic in science education

AbstractThe concepts of sky and visibility distance, as perceived by different learners, are investigated for the first time as a subject of a science education research. Mental models of students with regard to the subject were elicited. They were interpreted in terms of two‐level hierarchy: schemes and facets‐of‐knowledge (defined in the paper). Our results suggest that many students do not consider sky to be a scientific (physical) concept. The majority perceives the sky as having an oblate profile. Among the parameters that determine this profile were mentioned daytime, atmosphere, geometry of the situation, and weather conditions. The students hold two major explanatory views (schemes) with regard to the sky: “the sky is the atmosphere” and “the sky is the appearance of space.” With regard to the visibility distance, the two following schemes prevail: “vision weakens with the distance” and “natural obstacles determine vision distance.” No significant correlation was found between the views regarding the sky appearance and the vision distance. Students do not relate Moon illusion to the profile of sky or visibility distance. The notions of sky and visibility distance are argued for inclusion into science curriculum, and implications of the findings to a constructivist instruction of the considered concepts and phenomena are discussed. © 2004 Wiley Periodicals, Inc. Sci Ed 88:574–593, 2004

Phylogeographical structure, postglacial recolonization and barriers to gene flow in the distinctive Valais chromosome race of the common shrew (Sorex araneus).

Using one male-inherited and eight biparentally inherited microsatellite markers, we investigate the population genetic structure of the Valais chromosome race of the common shrew (Sorex araneus) in the Central Alps of Europe. Unexpectedly, the Y-chromosome microsatellite suggests nearly complete absence of male gene flow among populations from the St-Bernard and Simplon regions (Switzerland). Autosomal markers also show significant genetic structuring among these two geographical areas. Isolation by distance is significant and possible barriers to gene flow exist in the study area. Two different approaches are used to better understand the geographical patterns and the causes of this structuring. Using a principal component analysis for which testing procedure exists, and partial Mantel tests, we show that the St-Bernard pass does not represent a significant barrier to gene flow although it culminates at 2469 m, close to the highest altitudinal record for this species. Similar results are found for the Simplon pass, indicating that both passes represented potential postglacial recolonization routes into Switzerland from Italian refugia after the last Pleistocene glaciations. In contrast with the weak effect of these mountain passes, the Rhône valley lowlands significantly reduce gene flow in this species. Natural obstacles (the large Rhône river) and unsuitable habitats (dry slopes) are both present in the valley. Moreover, anthropogenic changes to landscape structures are likely to have strongly reduced available habitats for this shrew in the lowlands, thereby promoting genetic differentiation of populations found on opposite sides of the Rhône valley.

International Inequality in the Age of Globalization: Japanese Economic Ascent and the Restructuring of the Capitalist World-Economy

This paper shows how Japanese ?rms and the Japanese state constructed a development model based on the steel industry as a generative sector that drove Japan’s economic ascent in the world-historical context of U.S. hegemony. We make three arguments in this paper. First, there is a new model of capital accumulation that does create new forms of social inequality by redistributing costs and bene?ts in very di?erent ways than earlier models. Second, Japanese ?rms and the Japanese state created this new model of capital accumulation and social inequality via mechanisms including joint ventures, long term contracts, and other forms of international trade and investment, not U.S.-based transnational corporations, as is usually assumed. Third, world-systems theory reconstructed through the lens of the new historical materialism explains this restructuring of the capitalist world-economy as the outcome of Japan’s economic ascent over the last ?fty years. Further, we argue that this new model of capital accumulation has had similar impacts on redistributing the costs and bene?ts of development between core and peripheral regions of the capitalist world-economy in a wide range of global industries. These strategies created a tightly linked set of technological and organizational innovations to overcome the natural and social obstacles to Japanese development, dramatically increase Japan’s international economic competitiveness by lowering production costs in all sectors of the economy, turn Japan into the world’s largest exporter of manufactured products, restructure a range of global industries, and recreate the world-system hierarchy in support of Japanese development. In particular, organizational inno-vations in the use of long term contracts and joint ventures in raw materials industries to foster global excess capacity and lower rents to resource extracting ?rms and states reallocated the costs of providing the material building blocks of Japanese development to the states and ?rms of its new raw materials periphery. This competitive advantage drove Japanese capital accumulation and economic ascent, and simultaneously drove underdevelopment in Japan’s periphery. These Japanese innovations became key elements of globalization as U.S. and European transnational corporations and states sought to compete with Japan. Joint ventures, long-term contracts, and other forms of inter?rm cooperation have replaced vertically integrated foreign direct investment, the earlier U.S. model of capital accumulation and international economic linkage, as the model for global industries.

Optimum primary and supplementary signals optimizing the seismic data resolution

Often in practice, when generating seismic waves on a line, even with a wide-band source, numerous natural and technical obstacles cause a low resolution of reflection seismograms. In this case, the economy of the survey should be taken into consideration and rather than ignoring preexisting data, generating additional signal to complement the preexisting data should be tried. This paper describes how this can be done to optimize the resolution of the combined data. The new approach requires a fundamental change in the field technique such that records with different spectral characteristics (RDSC) are now generated from each source–receiver pair. These coincident records share a common reflectivity series, but differ from each other in wavelets and noise. A comprehensive theory for optimum processing (deconvolution) of any available suite of the RDSC is developed. The solution for the problem is a particular case of multichannel Wiener filtering. It can be thought of as two successive procedures. The first is optimum frequency-dependent weighted stacking of the RDSC. The second is single-channel zero-phase Wiener deconvolution filtering of the previous output. This representation enables suggested multichannel filtering to be easily implemented. The effectiveness of the method as well as its advantage over straight summing of the RDSC, followed by single-channel Wiener deconvolution filtering, are corroborated theoretically and demonstrated with field data. Furthermore, a solution is suggested for the problem to evaluate the spectrum of an optimum supplementary signal. The signal contributes to the available set of the RDSC and yields either maximum resolution with limited energy expenses or a certain desired resolution with minimum, but unrestricted energy expenses at the output of the optimum procedure. The optimum distribution of the spectral energy of a primary signal along the frequency axis is a particular case of the above problem with no preexisting data.

On Being First: Dogma, Disease and Domination in the Rise of an African Church

What might the early institutional history of an indigenous African Church reveal about the institutionalisation of religious innovation? What might findings suggest about the impact of both internal organisational processes and extra-institutional pressures on the routinization of charisma? This article addresses these questions by examining the rise of Christ Apostolic Church, an Aladura church of the Yoruba of Nigeria, and focusing on the interplay of first, the global propagation of Christianity; second, colonial domination; third, symbolic reformulation; and finally, the pursuit of well-being in the face of epidemic disease. This investigation provides a case study of how people negotiate social and natural obstacles while constructing enduring institutional structures. Furthermore, it is argued that, rather than obstructing this religious movement, epidemics, colonial domination and missionary opposition fuelled its transformation into an institutional church.

ABSTRACT: Best Technology Practices To Reactivate Macuspana Gas Province, Southern Mexico

Abstract Mexico's gas needs for the beginning of the next century are well acknowledged. Major gas demand will come from the oil industry, the growing number of gas-driven electricity plants, transportation, and other industrial and residential consumers. Aware of this, Pemex is implementing a national strategy focused on gas. Macuspana Basin with its offshore extension is located in the states of Tabasco and Campeche in southern Mexico. It is an elongated Neogene basin formed between the Yucatan Platform to the east and the Reforma Akal Folded Belt to the west. This basin contains a thick sequence of fluvio-deltaic and open marine Neogene sediments cut by numerous growth faults associated with rollover anticlines and amorphous shale bodies. The basin is a prolific gas province, in a mature stage of exploration and production. During its 90 years of exploratory history, over 700 exploratory wells have been drilled and 36 fields discovered; so far only 11 of them are commercially exploited. Among other important issues, technology practices will play an important role in facing the challenges of reactivating this basin. Following, a brief description of technology practices in Macuspana Basin is presented. To properly plan and execute seismic activities it is very important to have a clear picture of the ground surface. The use of seismic orthomaps to honor natural and cultural obstacles during the design and execution of seismic activities is now a common Pemex practice. In addition to orthomaps, in some regions aeromagnetic surveys are needed to accurately identify old but active buried pipelines. Based on geologic targets, access, cost, and time needed for operation, a center-shot cross swath was chosen for seismic acquisition because it increases the range attributes (fold, offset, and azimuth distribution) and affords operational simplicity in the field. The use of AVO as a direct hydrocarbon indicator in gas-filled clastic rocks is widespread along the Gulf Coast. A methodology for high-quality prospect generation and reduced turnarounds was also tested. It consisted of a series of steps that included: synthetic seismograms, seismic attributes extraction, correlation between petrophysical properties and seismic attributes, depth conversions, and intensive training in workstation applications. The fulfillment of exploration and production targets in the Macuspana Basin over the next five years will demand intensive operations that must rely on high-performance leadership and teamwork practices, as well as careful selection, adoption, and application of best technology practices that transform Pemex investments into profitable ventures. End_of_Record - Last_Page 8---------

D'un rivage à l'autre : image d'errance et de terres Promises

In film, the ocean serves as a very rich backdrop against which individual lives and collective stories are projected. Many movies have portrayed Jewish characters, whose lives have been associated, in one way or another, with the sea. In documentaries and fiction films, the history of Jewish people has been recorded : Hasty departures and arrivais, overcoming natural obstacles in order to reach a promised land, be it real or mythical, sea crossings, pervade those films. From « biblical » movies to films portraying modem Jewish heroes, the sea embodies the various voyages that Jews have had to undertake, their resilience, their fears and their hopes.

Outward Migration of Houbara Bustards from Two Breeding Areas in Kazakhstan

We studied the migration patterns of nine Houbara Bustards (Chlamydotis undulata macqueenii) from two breeding areas in the Republic of Kazakhstan by tracking via satellite during two consecutive seasons. All the birds from the Taukum desert (east Kazakhstan) migrated southwest towards the Kyzylkum desert and then south-southeast towards Iran, south Afghanistan, and north Baluchistan. All the birds from the Buzachi peninsula (west Kazakhstan) migrated south towards Turkmenistan and Iran and then west towards south Iraq. Houbara followed similar migration routes in 1995 and 1996. All birds bypassed natural obstacles such as seas and mountains. The total distance covered by Houbara during their outward migration ranged from 1,600 to 2,320 km. We observed important interindividual variation in migration timing, duration, and patterns. Migration duration ranged from 14- 73 days. Travel rate between the breeding grounds and the wintering grounds was 24 to 151 km day -1 , with up to 323 km covered in one day.

Injuries associated with snowmobiles, Alaska, 1993-1994.

To characterize the nature and burden of snowmobile injuries in Alaska by examining injury deaths and hospitalizations associated with snowmobiles and comparing these with injury deaths and hospitalizations associated with on-road motor vehicles. The authors used vital statistics, medical examiner, Department of Public Safety, and Department of Transportation records to identify snowmobile injury deaths, and used vital statistics mortality files to identify on-road motor vehicle injury deaths. The Alaska Trauma Registry provided data on hospitalizations. The number of vehicles in use in 1993-1994 was estimated from snowmobile sales and on-road motor vehicle registrations. For 1993-1994, injury death and hospitalization rates were greater for snowmobiles than for on-road motor vehicles. In northern Alaska, snowmobile injuries outnumbered on-road motor vehicle injuries. A total of 26 snowmobile injury deaths were reported; 7 decedents drowned after breaking through ice and 8 were ejected from vehicles. More than half (58%) of the snowmobile injury deaths involved a natural object such as a boulder, ravine, or river. Of the 17 decedents for whom blood alcohol concentrations were available, 11 (65%) had blood alcohol concentrations > or = 100 mg/dL. Natural obstacles and alcohol intoxication contribute to the high risk of injury death associated with snowmobile use. Injury control strategies, including trail development and improvement, should be evaluated.

Prey Killing by Eurasian Kestrels: The Role of the Foot and the Significance of Bill and Talons

Csermely, D., Berte, L. and Camoni, R. 1998. Prey killing by Eurasian Kestrels: the role of the foot and the significance of bill and talons. - J. Avian Biol. 29: 10-16. The technique used by birds of prey to kill their quarry has rarely been described in detail. Although it is common to watch a raptor hunting, distance and natural obstacles normally prevent the observer from observing what actually happens to the prey after being grasped by the bird. Therefore, we studied the predatory sequence and killing technique displayed by a sample of ten wild Eurasian Kestrels temporarily held in captivity because of various injuries. They were offered individually either a laboratory mouse or young laboratory rat. Direct observation was complemented by necropsy of the prey confirming that bill strikes frequently observed after grasping the prey are not used to kill it but merely to damage its central nervous system thereby minimising escape attempts. Furthermore, talons are not used as weapons at all, but only as tools that elongate the toes to hold the quarry more firmly. In contrast, several signs indicating death by suffocation were regularly found and these were confirmed by inspection of rodents sacrificed by CO2. We also discuss a hypothesis explaining the adaptive and evolutionary significance of the kestrel's use

Analiza uticaja brzine proticanja tečnosti na dinamičko ponašanje slobodno oslonjene cevi

In design of mobile pipeline systems for transport of fluids and finely divided solids there are different problems to be solved such as, for example, spanning of natural and artificial obstacles like highways, railroads,... One of practical solutions is to design pipes to serve as bridges at the same time. Although cheaper, this solution has one disadvantage - fluid flow velocity is limited in order not to bring the structure into danger. In this paper possible states of the structure are analyzed and the conclusion about the permitted fluid flow velocity through pipes is given as well.