Bayesian Semi-supervised Learning with Graph Gaussian Processes

We propose a data-efficient Gaussian process-based Bayesian approach to the semi-supervised learning problem on graphs. The proposed model shows extremely competitive performance when compared to the state-of-the-art graph neural networks on semi-supervised learning benchmark experiments, and outperforms the neural networks in active learning experiments where labels are scarce. Furthermore, the model does not require a validation data set for early stopping to control over-fitting. Our model can be viewed as an instance of empirical distribution regression weighted locally by network connectivity. We further motivate the intuitive construction of the model with a Bayesian linear model interpretation where the node features are filtered by an operator related to the graph Laplacian. The method can be easily implemented by adapting off-the-shelf scalable variational inference algorithms for Gaussian processes.Comment: To appear in NIPS 2018 Fixed an error in Figure 2. The previous arxiv version contains two identical sub-figure

Ophiolites in the Eastern Cordillera of the central Peruvian Andes

A discoutinuous NNW-SSE trending belt of scattered ultraiuafic (UM) and subordínate mafic (M) rocks ís exposed alona some 250 km in the Eastern Cordillera of the peruvian Andes (Junin and Huanuco Departnients. -°"-12° S). New data questiou tlieír pieviousty assuuned [1.2] intrusive origin. Work, in progress shows tLat the essential geologic and tecronk featiires are comnion to most of them, as will t e shown on the southeniniost occurrences: Tapo and Acobaniba (Tarraa proviuce). The Tapo massif is the most conspkuoiis and the oaty one with chiomite mining history. It is a lens-shaped body, 5 km long [NV-SE direction) and 1 -2 km wide. lying on detritaí sedirnents of the Lower Carboniferous Ambo Group [3], and comprising extreniely tectomsed and serpentinised peridotiles wilh subordínate podiform chroirdtite bodies. nieta-gabbros or amphibolites The Acobamba oecurrences couiprise serpentinites aud subordínate meta-gabbros [A]. in contact with phyllites of the Precarnbnan (?) Huacar Group (Maraáón Complex)

Neoproterozoic ultramafic and mafic magmatism in the Eastern Cordillera of the central peruvian Andes: the Tapo Massif

A highly dismembered assemblage of ultramafic and mafic rocks is exposed in the Eastern Cordillera of the Central Peruvian Andes, extending along a discontinuous NW-SE belt over some 250 km between 12° and 9° S of latitude. One of the most important occurrences is the Tapo Mafic-Ultramafic Complex, which occurs at 3750 to 4200 m above sea level, 2 km to the west of Tapo locality, in the Tarma province, about 200 Km west of Lima. The Tapo complex is a lens-shaped body, 5 km long and 1-2 km wide, that consists mainly of strongly serpentinized peridotites and some gabbros. Several small open pits won chromite from podiform chromitite lenses ( ≥60 chromite) and from disseminated chromite in serpentinite. The main structural trend of the Tapo Complex is NW – SE and the massif is tectonically emplaced upon Lower Carboniferous sedimentary rocks. The rocks of the Tapo massif are overprinted by metamorphism reaching amphibolite facies (see Willner et al, 2010, for more information on the metamorphic conditions). The main purpose of this work is to constrain the age determination of the Tapo Complex, using Sm-Nd technique direct dating of chromites and, also, amphibole, plagioclase and whole-rock samples from the host gabbro. In addition K-Ar age determination on amphibole is presented to date the metamorphic overprint

New data on the ophiolitic VMS deposits of Moeche (Cabo Ortegal Complex, NW Spain)

As a result of the variscan collision, several allochtonous complexes were emplaced on the Iberian margin in Devonian times, among them the Cabo Ortegal Complex comprising the Moeche ophiolitic sequence. Copper has been won from several mines (Piquitos I & II, Barqueira, Maruxa) from disseminated ores and thin massive sulphide layers in the Moeche Unit, a strongly deformed meta-volcanic sequence comprising mainly quartz-chlorite schists and mylonites, which defines the top of the ophiolite. The ores were metamorphosed and strongly deformed under brittle conditions (for pyrite), but their textures are often apparently post-deformational, due to very common solution-transfer processes; they are composed mostly of pyrite and chalcopyrite, with minor sphalerite, pyrrhotite, etc., and with traces of native gold and PGE. The geology, mineralogy, and geochemistry of the orebodies relate closely to VMS of the Cu-Zn (Cyprus) type. Fluid inclusion studies allowed an estimation of metamorphic conditions at pressures of 2/2’5 kb and T 325/350ºC. New determinations using the chlorite geothermometer yield temperatures around 320 ºC, corresponding to pressures near 2 kb according to the isochores deduced from the fluid inclusion study, although in the Barqueira mine higher temperatures, up to 350 ºC, are found, corresponding to presssures up to 2’5 kb. Pb isotopic compositions of pyrite point to a double source of Pb, i.e. a main mantle and a subordinate crustal source. The values for 87SR/86Sr in pyrite support this interpretation, but some results suggest later mobilization in an open system, corresponding to solution-transfer. Age determinations of pyrite deduced from the Pb isotope uranogenic graph, ≈ 480 Ma, do not fit with the metamorphic ages published for the Moeche Unit, and might point to the age of Pb extraction from the mantle

Rolling contact fatigue behavior of dual-phase austempered ductile iron

In this work the rolling contact fatigue (RCF) behavior of dual-phase austempered ductile iron (ADI) was studied and compared to that of conventional ADI. The effect of surface finishing (manual vs. automatic grinding) on the surface properties and RCF endurance was also analyzed. RCF tests were performed in a flat washer type testing rig and using lubricated pure rolling conditions. RCF tests results were analyzed using the two-parameter Weibull distribution and the Weibayes method. The results indicated that the dual-phase ADI metal matrix was composed of 94% ausferrite and 6% free allotriomorphic ferrite, approximately. The hardness of conventional ADI was higher than that of dual-phase ADI. The residual stresses were compressive in all the cases with similar average values for ADI and dual-phase ADI. Relative to manual grinding, the automatic process increased slightly the surface hardness and reduced by around a 50% the residual stresses of both ADI and dual-phase ADI. Regarding RCF, failures were characterized by the typical concentrated damage in the form of spalls. No significant differences in the RCF endurance of ADI and dual-phase ADI were observed. No differences in the RCF endurance attributable to the surface finishing method were identified in the current tests.Fil: Colombo, Diego Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Dommarco, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Basso, Alejandro Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Inclusiones fluídas e isótopos de Pb y Sr en Chipmo y Poracota, región minera de Orcopampa, Perú. Implicaciones para la exploración

Chipmo y Poracota forman parte de los depósitos epitermales miocénicos de oro y plata de los Andes centrales en el sur del Perú, entre los 3900 y 4900 metros sobre nivel del mar. Figura 1. Políticamente pertenecen a las provincias de Castilla y Condesuyos en la región de Arequipa y actualmente representan la mayor producción subterranea de oro del Perú. La producción total, a finales del 2009 fue de 2.1 Moz Au – 2.0 Moz Chipmo y 0.1 Moz Poracota–, cuentan con reservas del orden de 0.7 Moz Au y recursos estimados superan los 1.0 Moz Au. Chipmo es el deposito mas importante de la región de Orcopampa, en los últimos 15 años importantes publicaciones se han venido desarrollando: Swanson, 1998; Noble, 1999; Caddey and Sabastizagal, 1999; Mayta, 1999, Salazar et al., 2009 y Salazar 2008 y en Poracota cabe destacar a Bradford, 1999; Miranda Vidal, 2006 y Sarmiento, 2008

Resultados oncológicos da nefrectomia radical laparoscópica no tratamento do carcinoma renal

PURPOSE: To report the 5-year oncological outcomes of patients undergoing laparoscopic radical nephrectomy for renal cancer compared to a cohort of patients undergoing open radical nephrectomy. METHODS: We retrospectively analyzed the data of 88 patients undergoing radical nephrectomy for renal cell carcinoma prior to January 2000. Of these, 45 patients underwent laparoscopic radical nephrectomy, and 43 patients underwent open radical nephrectomy. Inclusion criteria comprised clinically organ-confined tumors of 15 cm or less in size without concomitant lymphadenopathy or vena cava thrombus. Oncological follow-up data were obtained from charts, radiological reports, and phone calls to patients or their families, and were calculated from the date of surgery to the date of last appointment with physician or date of death. RESULTS: All laparoscopic procedures were completed without open conversion. On comparing the laparoscopic radical nephrectomy and open radical nephrectomy groups, mean tumor size was 5. 8 vs 6.2 cm (P = . 44), mean blood loss was 183 vs 461 mL (P = . 004), and mean operative time was 2.8 vs 3.7 hrs (P < . 001). Over a mean follow-up of 5 years in the laparoscopic radical nephrectomy group and 6 years in the open radical nephrectomy group, the overall survival was 81% vs 79% (P = . 47), and cancer-specific survival was 90% vs 92% (P = . 70) , respectively. CONCLUSIONS: Laparoscopic radical nephrectomy for renal cancer confers equivalent 5-year oncological outcomes to those of open surgery.OBJETIVO: Relatar os resultados oncológicos após 5 anos de seguimento em pacientes submetidos a nefrectomia radical laparoscópica para tratamento do câncer renal, comparando esses com os resultados obtidos com um grupo de pacientes submetidos a nefrectomia radical aberta. MÉTODOS: Foram analisadas retrospectivamente as informações obtidas de 88 pacientes submetidos a nefrectomia radical para o tratamento do carcinoma renal realizadas previamente a Janeiro de 2000. Destes pacientes, 45 foram tratados com nefrectomia radical laparoscópica e 43 com nefrectomia radical aberta. Foram incluídos pacientes com tumores localizados com tamanho máximo de 15 cm, sem adenopatia ou sinal de envolvimento de veia renal na avaliação radiologica pré-operatória. As informações sobre o seguimento dos pacientes foram obtidas a partir de prontuários, laudos de exames radiológicos e ligações telefônicas para pacientes e/ou familiares. O seguimento foi calculado desde a data da cirurgia até a última consulta médica ou data de falecimento. RESULTADOS: Todos os procedimentos laparoscópicos foram realizados sem conversão para a técnica aberta. O tamanho médio tumoral foi de 5.8 e. 6.2 cm (P=0.44), perda sanguínea estimada de 183 e. 461 mL (P=0.004), e tempo operatório de 2.8 e. 3.7 horas (