426 research outputs found
Crustal deformation of Mars associated with the true polar wander
No full textLarge scale true polar wander episodes are considered to have occurred several times in Mars. Because they accompany relocation of the Martian equatorial bulge, milli-strain level horizontal extension/compression is expected to have occurred as well as kilometer scale vertical crustal movements. Here we pick up one of such episodes reported by Perron et al. (2007), and try to compare the expected strikes of faults with those observed in satellite images. Wrinkle ridges seem to have preferred orientations aligned with the meridian connecting the present and ancient poles, which suggests that some of those may reflect the crustal stress imposed by this true polar wander episode
Human is to wander: poems
No full textColorado prize for poetry, 2022.If we are always at war, is all poetry then war poetry? Adrian Lürssen's Human Is to wander is a book of dislocation, migration, and witness at a time of war-but whose war, fought where, and at what costs to whom? Born and raised in apartheid-era South Africa, Lürssen migrated to the U.S. as a teen in order to avoid military service at a time when the country's authoritarian regime engaged in a protracted, largely unknown war in Angola. Years later, as a father of young children in his adopted country, echoes of everything his family thought they had left behind has returned: endless bloody conflicts on the horizon; an alarming rise of authoritarianism and nationalistic fervor; pervasive racism, inequality, and daily violence in a country whose mythic promise was once held as freedom, equality, opportunity. In Human Is to wander, Lürssen explores these echoes of his personal history within a landscape that is familiar and unfamiliar all at once. Neither the brutally oppressive South Africa of his childhood nor the precarious United States of today, Lürssen's landscape emerges in the broken rhyme between "troop" and "troupe" where "our captions / are picture less" and "the plan to explain is absolute, but only an entrance." His is an inner landscape as song no longer sung in a mother tongue, in which the human cost of war, climate crisis, and forced migration is "all part of the explanation." Lürssen uses collage, constrained cut-up, Oulipean procedures, abecedarian, and other generative play to allow poems to emerge that respond to the turmoil and dislocation of this violent century, attempting to witness if not understand his-and our-place in it.--Provided by publisher
Beam wander of random electromagnetic Gaussian-shell model vortex beams propagating through a Kolmogorov turbulence
No full textBeam wander of random electromagnetic Gaussian-Shell model (EGSM) vortex beams propagating through atmospheric turbulence is investigated. We develop the expression for beam wander of random EGSM vortex beams in theory. The effects of topological charge, turbulence strength, initial spatially coherent length, transverse scale, and wavelength on beam wander are illustrated numerically. The numerical results show that vortex beams with both positive and negative topological charges have the same beam wander, decreasing the coherent length and decreasing the transverse scale, or increasing the topological charge, can decrease the beam wander. In free-space optical (FSO) communication, we can choose beams with smaller coherent length, smaller wavelength, and larger topological charge to reduce beam wander. (C) 2014 Elsevier By. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000345688200011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701OpticsSCI(E)[email protected]
Beam wander of electromagnetic partially coherent flat-topped beam propagating in turbulent atmosphere
No full textBeam wander of an electromagnetic partially coherent flat-topped (EPCFT) beam propagating through turbulent atmosphere is studied. The analytical expression of beam wander effect is obtained. The influence of source size, source spatially coherent lengths, degree of polarization, and beam flatness order are studied in detail. It has been shown that by adjusting these parameters appropriately, the beam wander effects could be greatly reduced. Compared with increasing the degree of polarization, the beam wander could be reduced much more effectively by increasing the beam flatness order. The EPCFT beam can greatly reduce the beam wander effect and the parameters should be chosen very carefully for different applications. (C) 2013 Elsevier GmbH. All rights reserved.OpticsSCI(E)[email protected]
Capacities for Long-Distance Free-Space Optical Links Under Beam Wander Effects
No full textThe performance of the long-distance horizontal free-space optical (FSO) communication link under beam wander effects is studied from the perspective of information theory. Based on the newly proposed beam wander model and strong fluctuation theory, the influence of beam wander is directly included in the scintillation and then the statistical model for intensity fading is presented. The impact of beam wander on the average and outage capacities of the FSO link is investigated, showing that an optimum transmitter beam radius can be selected to make the system achieve maximum average capacity and minimum probability of capacity outage.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000281476800010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicOpticsPhysics, AppliedSCI(E)EI9ARTICLE141069-10712
Tanguá Benach. Ancestors, land and wander
No full textEste texto trata de caminar por tanguá benach,camino ancestral del pueblo indígena Camëntsá. La autora puso las huellas; trata de organizar la palabra, narrar, otra forma de andar y hacer camino. Mientras va, viene, y en devuélvase está el misterio. Es una etnografía del camino, de la vida y de la muerte, de los ancestros y de la tierra de la que somos; es una etnografía de los andares.This text is about walking through tanguá benach, ancestral path of the Camëntsá indigenous people. The author puts the prints; she tries to organize the words, narrate, another way of walking and making the way. While going, she comes, and the mystery is in returning . It is an ethnography of the path, of life and of death, of the ancestors and of the landwe are from. It is an ethnography of the wander
Autoritarisme et parlementarisme : Quelques considérations sur les initiatives législatives au Brésil
No full textIn the trend of Benjamin Constant's theory on the « Pouvoir modérateur », the author establishes how is has influenced the organisation of constitutional power through all the different bresilian governments since 1824 until the recent preliminary work to the last constitution of 5 october 1988.Partant des idées de Benjamin Constant sur le pouvoir modérateur, l'auteur s'applique à démontrer l'influence de celles-ci sur l'organisation du pouvoir constitutionnel brésilien au travers des différents types de gouvernement qui se sont succédé depuis 1824 jusqu'aux dernières initiatives de préparation de la Constitution du 5 octobre 1988.Wander Chaves Bastos Aurelio. Autoritarisme et parlementarisme : Quelques considérations sur les initiatives législatives au Brésil. In: Revue internationale de droit comparé. Vol. 42 N°3, Juillet-septembre 1990. pp. 955-966
Adolescents involved in decision-making: clinic conversations about the human papillomavirus and vaccination
No full textThoughtful and deliberate, adolescent decision-making is not well understood. For example, adolescents and parents visit with physicians for routine health care however the extent that adolescents participate has not been satisfactorily investigated. This study used surveys, conversations, and observations of healthy adolescents, parents, and physicians discussing issues of optional vaccination against human papillomavirus infections to interrogate the gap in understanding adolescent decision-making. The decision involves if and when to receive vaccination to prevent sexually transmitted infections that potentially cause adult cancers. Thus, sexual behavior and vaccination effectiveness infuse these discussions. Survey results from several hundred 11 thru 21 year-old Black, Hispanic, and White adolescents and parents showed adolescents’ older age, female gender, and suburban residence as significant predictors of vaccination acceptance; race, education, HPV knowledge, and judgments of adolescent autonomy were not. Survey conversations and observations substantiated that parents were the decision-makers. Information did not influence decisions; parents were influenced by their personal beliefs about vaccinations and sexual debut and their adolescents’ age. Adolescents indicated on their surveys that they would make vaccination decisions which contradicted their survey conversations and participant-physician encounters that showed adolescents deferring the decision to their parents. During survey conversations, when their parents were not present, adolescents posed thoughtful questions and engaged in HPV discussions. During participant-physician encounters adolescents rarely participated. Notably, if adolescents chose to speak they protested the shot and rallied to postpone it. An adolescent focused on a vaccination presents a vulnerable and asexual image. Adolescents’ participation in HPV vaccination decision-making is not determined by their decision-making competence but by their social competency. Both parents and adolescents understand the sexual subtexts looming in the background and neither want those perceptions to rise to the forefront. Reformulating the manner and content of HPV discussions may increase adolescent participation and vaccination reception.Ph. D.Includes bibliographical referencesIncludes vitaby Marla DeMesquita Wande
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