HCI for peace: from idealism to concrete steps

This panel will contribute diverse perspectives on the use of computer technology to promote peace and prevent armed conflict. These perspectives include: the use of social media to promote democracy and citizen participation, the role of computers in helping people communicate across division lines in zones of conflict, how persuasive technology can promote peace, and how interaction design can play a role in post-conflict reconciliation

Lifts of convex sets and cone factorizations

In this paper we address the basic geometric question of when a given convex set is the image under a linear map of an affine slice of a given closed convex cone. Such a representation or 'lift' of the convex set is especially useful if the cone admits an efficient algorithm for linear optimization over its affine slices. We show that the existence of a lift of a convex set to a cone is equivalent to the existence of a factorization of an operator associated to the set and its polar via elements in the cone and its dual. This generalizes a theorem of Yannakakis that established a connection between polyhedral lifts of a polytope and nonnegative factorizations of its slack matrix. Symmetric lifts of convex sets can also be characterized similarly. When the cones live in a family, our results lead to the definition of the rank of a convex set with respect to this family. We present results about this rank in the context of cones of positive semidefinite matrices. Our methods provide new tools for understanding cone lifts of convex sets.Comment: 20 pages, 2 figure

Ofiuroideos del Cretácico Inferior de Patagonia: primer registro fósil articulado para el Mesozoico de América del Sur

The first articulated remains of ophiuroids for the Mesozoic of South America are described from the Lower Cretaceous of Neuquén Basin, Argentina. The taxonomic analysis allows the assignment of the material described herein to the extinct genus Ophiopetra. The specimens belong to a new species, but considering the poor preservation, a new name is not introduced, as it would be based on an incomplete diagnosis. Certain characteristics (e.g., the diameter of the disc, the width/height ratio of the vertebrae) suggest that these ophiuroids are paedomorphic specimens. In light of the latest classification of the Ophiuroidea, and new insights on the spine articulation microstructure of Ophiopetra lithographica presented herein, a transfer of Ophiopetra to the family Ophionereididae within the order Amphilepidida is proposed. This material expands the palaeogeographic record of this genus, since it represents the first remains of Ophiopetra described in the Southern Hemisphere. It is also the first Cretaceous record of the genus worldwide.Fil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; ArgentinaFil: Giachetti, Luciana María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; ArgentinaFil: Stöhr, Sabine. Swedish Museum of Natural History; SueciaFil: Thuy, Ben. Natural History Museum Luxembourg; LuxemburgoFil: Perez, Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Comerio, Marcos. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Pazos, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Bed-thickness and grain-size trends in a small-scale proglacial channel-levée system; the Carboniferous Jejenes Formation, Western Argentina: Implications for turbidity current flow processes

Preserved in Quebrada de las Lajas, near San Juan, Argentina, is an ancient subaqueous proglacial sedimentary succession that includes a small-scale (ca 50 m thick and ca 200 m wide) channel–levee system with excellent exposure of the channel axis and levee sediments. Coeval deposition of both the channel axis and the levees can be demonstrated clearly by lateral correlation of individual beds. The channel axis consists predominantly of a disorganized, pebble to boulder conglomerate with a poorly sorted matrix. The channel axis varies from 10 to 20 m wide and has a total amalgamated thickness of around 50 m. Beds fine gradationally away from the cobble–boulder conglomerates of the channel axis within a few metres, transitioning to well-organized pebble to cobble conglomerates and sandstones of the channel margin. Within 60 m outboard of the channel axis in both directions, perpendicular to the trend of the channel axis, the mean grain size of the beds in the levees is silt to fine-grained sand. Deposits in this channel–levee system are the product of both debris flows (channel axis) and co-genetic turbidity currents (channel margins and levees). Bed thicknesses in the levees increase for up to 10 to 25 m away from the channel axis, beyond which bed thicknesses decrease with increasing distance. The positions of the bed thickness maxima define the levee crests, and the thinning beds constitute the outer levee slopes. From these relationships it is clear that the levee crest migrated both away from and toward the channel axis, and varied in height above the channel axis from 4 to 5 m (undecompacted), whereas the height of the levee crest relative to the distal levee varied from 4.5 to 10 m, indicating that the channel was at times super-elevated relative to the distal levee. Bed thickness decay on the outside of the levee crest can be described quite well with a power-law function (R2=0.85), whereas the thickness decay from the levee crest toward the channel axis follows a linear function (R2 =0.78). Grain-size changes are quite predictable from the channel margin outward, and follow logarithmic (R2=0.77) or power-law (R2=0.72) decay curves, either of which fit the data quite well. This study demonstrates that, in at least this case: (i) levee thickness trends can be directly related to channel-flow processes; (ii) individual bed thickness changes may control overall levee geometry; and (iii) levee and channel deposits can be coeval.Fil: Dykstra, Mason. Colorado School of Mines; Estados UnidosFil: Kneller, Ben. University of Aberdeen; Reino UnidoFil: Milana, Juan Pablo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Geología "Dr. Emiliano Aparicio"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

Foucault, capitalismo y sexualidad: tensiones conceptuales circa 1976

Este artículo realiza un analisis del concepto de “capitalismo” en la Historia de la Sexualidad de Michel Foucault publicada en 1976 detallando el debate teórico con el marxismo y el neoliberalismo. En oposición a las nociones contractualistas, Foucault fundó una nueva agenda de investigación que distanciandose de la hipótesis represiva caracterizaba a la sexualidad como unidad artificial de caracter histórico relativamente reciente. El autor proveía ejemplos históricos de la emergencia de la sexualidad que coincidían cronológicamente con el surgimiento del capitalismo. Al mismo tiempo, proponía desvincular la relación entre sexualidad y capitalismo recurriendo a concepciones binarias que oponían oriente y occidente, o señalando a la confesión cristiana como factor precapitalista en la genealogía de la sexualidad. Puede observarse una ambivalencia respecto del uso mismo de la categoría de capitalismo, que en algunos casos está referida de manera más o menos explícita, y en otros casos está negada. Dado que la Historia de la Sexualidad se convirtió en un texto fundante para el conjunto de la disciplina, la ambivalencia inicial frente al marxismo y a la noción de capitalismo se amplificó en otros estudios realizados durante las últimas cuatro décadas.This article engages in an analysis of the concept of “capitalism” in Michel Foucault’s History of Sexuality with an emphasis on the theoretical debate with Marxism and Neoliberalism. In opposition to contractualism, Foucault founded a new research agenda distancing himself from the repressive hypothesis and characterizing sexuality as an artificial unit of relatively recent historical character. The author provided examples of the historical emergence of sexuality that coincided chronologically with the rise of capitalism. Meanwhile, he also proposed to disassociate sexuality and capitalism turning to binary approaches that opposed West and East, or identifying pre-Capitalist Christian confession as an early stage in the genealogy of sexuality. An ambivalence in the use of the category of capitalism is present throughout the text: sometimes the term surfaces explicitly while it is denied in other paragraphs. Since the History of Sexuality became a founding text for a discipline bearing the same name, the original ambivalence towards Marxism and the concept of capitalism was amplified in later studies during the last four decades

Probabilistic volcanic hazard assessment for pyroclastic density currents from pumice cone eruptions at Aluto Volcano, Ethiopia

Aluto volcano, in the Main Ethiopian Rift, is a peralkaline caldera system, which comprises conglomerations of rhyolite (obsidian) lavas and enigmatic pumice cones. Recent work at Aluto has found that pumice cone eruptions are highly unsteady, and form convective eruption plumes that frequently collapse to generate pyroclastic density currents (PDCs). We develop a methodology and present results for the first probabilistic volcanic hazard assessment (PVHA) for PDCs at a pumice cone volcano. By doing so, we estimate the conditional probability of inundation by PDCs around Aluto volcano, incorporating the aleatory uncertainty in PDC hazard. We employ a Monte Carlo energy cone modeling approach, which benefits from parameterization informed by field investigations and volcanic plume modeling. We find that despite the relatively modest eruptions that are likely to occur, the wide distribution of past vent locations (and thus the high uncertainty of where future vents might open), results in a broad area being potentially at risk of inundation by PDCs. However, the aleatory uncertainty in vent opening means that the conditional probabilities are lower (≤ 0.12), and more homogeneous, over the hazard domain compared to central-vent volcanoes (where conditional probabilities are often ≤ 1 close to the vent). Despite this, numerous settlements, amenities, and economically valuable geothermal infrastructure, lie within the most hazardous (P(PDC|eruption) ≥ 0.05) regions of Aluto caldera. The Monte Carlo energy cone modeling approach provides a quantitative, accountable and defendable background and long-term PVHA for PDCs from Aluto. These results could be combined in the future with hazard assessments relating to tephra fall and/or lava to develop a comprehensive volcanic hazard map for the caldera. Following appropriate parameterization, the approach developed here can also be used to compute a PDC PVHA at other volcanoes where vent location is uncertain

Mechanical, Stress and Flow Considerations for Piping Design of Centrifugal Compressors

TutorialThis tutorial covers a range of factors that must be considered in the piping design associated with the installation of any new centrifugal compressor system. Multiple factors must be balanced in the piping design to have an overall successful final installation. The compressor piping must be configured and supported in a manner to safety contain the mechanical forces from the internal fluid pressure as well as the weight of the piping, fittings and valves. Additionally, the piping must not place any unusually high loads on the compressor itself or any piping supports due to thermal expansion, pressure elongation or weight loads. Finally, the piping layout should result in an even flow velocity profile that does not result in any detrimental impact to the aerodynamic performance of the centrifugal compressor

HIV-2 Protease resistance defined in yeast cells

BACKGROUND: Inhibitors of the HIV-1 Protease currently used in therapeutic protocols, have been found to inhibit, although at higher concentrations, the HIV-2 encoded enzyme homologue. Similar to observations in HIV-1 infected individuals, therapeutic failure has also been observed for some patients infected with HIV-2 as a consequence of the emergence of viral strains resistant to the anti-retroviral molecules. In order to be able to define the specific mutations in the Protease that confer loss of susceptibility to Protease Inhibitors, we set up an experimental model system based in the expression of the viral protein in yeast. RESULTS: Our results show that the HIV-2 Protease activity kills the yeast cell, and this process can be abolished by inhibiting the viral enzyme activity. Since this inhibition is dose dependent, IC(50 )values can be assessed for each anti-retroviral molecule tested. We then defined the susceptibility of HIV-2 Proteases to Protease Inhibitors by comparing the IC(50 )values of Proteases from 7 infected individuals to those of a sensitive wild type laboratory adapted strain. CONCLUSION: This functional assay allowed us to show for the first time that the L90M substitution, present in a primary HIV-2 isolate, modifies the HIV-2 Protease susceptibility to Saquinavir but not Lopinavir. Developing a strategy based on the proposed yeast expressing system will contribute to define amino acid substitutions conferring HIV-2 Protease resistance