North-South Customs Unions and International Capital Mobility

This paper examines the implications of a North-South trade accord where investments in the Southern partner nation exhibit country risk. Our analysis demonstrates that North-South trade accords can serve as credibility-enhancing mechanisms that induce additional foreign capital inflows into Southern partner nations. The presence of sovereign risk changes the tradeoffs between trade creation and diversion, enhancing the potential for regional trade accords to increase the welfare of accord members.

Gold phosphide complexes

6 pages, 9 schemes, 6 figures.The vast majority of gold complexes with five group-element donor ligands contain tertiary phosphines, although compounds with amine, arsine or stibine ligands are also known. Although phosphide ligands, which are formed by deprotonation of non-tertiary phosphines, are closely related to the former, they have been employed to a lesser extent, mainly due to their lower stability. Thus, the chemistry of phosphido-bridged derivatives of the main group elements1-3 or transition metals4-6 has been a matter of interest for various research groups in the last few years. While there are many phosphido complexes with metals, mainly of groups 67-12 or 10,13-20 the chemistry of gold derivatives has experienced less progress in this field of research in spite of the possible catalytic behaviour of di- and polynuclear phosphido-bridged compounds.21 This is an interesting field of research, because the substitution of one or more protons by metal atoms allows the synthesis of homo- or hetero-polynuclear compounds in which the presence of a small bridging atom, such as phosphorus, may give rise to intermetallic contacts, which, as is known, are often responsible for surprising and interesting optical properties, such as luminescence, area with an increasing importance in the last years. This review focuses on gold phospide complexes derived from secondary phosphines (PR2H), primary phosphines (PRH2), primary diphosphines (PH2(CH2)nPH2) or from PH3. The moieties derived from all these complexes usually act as bridging ligands between more than one gold centre or between gold and other transition metal centres.Peer reviewe

A Proposal for a Modified Moller-Plesset Perturbation Theory

A modified version of the Moller-Plesset approach for obtaining the correlation energy associated to a Hartree-Fock ground state is proposed. The method is tested in a model of interacting fermions that allows for an exact solution. Using up to third order terms improved results are obtained, even more accurate in the limit of loosely bound particles. This result suggests the possible convenience of the scheme for the study of chemical bound problems.Comment: 10 pages, 1 figur

Chemoenzymatic synthesis of optically active 2-(2- or 4-substituted-1H-imidazol-1-yl)cycloalcanols. Chiral additives for (L)-proline

Enantiopure substituted imidazoles obtained by enzymatic kinetic resolution can be promising candidates as co-catalysts for aldol reactions catalysed by (L)-proline. These additives seem to form supramolecular complexes with the catalyst through the formation of H-bonds, leading to significant improvement in both the reaction rates and selectivity of the reaction. Herein, we present our results on the use of these substituted trans-2-imidazoyl-cycloalkanols as additives for the (L)-proline catalyzed direct aldol reaction between ketones and aromatic aldehydes

Update on Extended Treatment for Venous Thromboembolism

The importance of assessing the probability of venous thromboembolism recurrence, a condition that includes deep vein thrombosis and pulmonary embolism, lies in the fact that it is the most important factor in deciding the duration of anticoagulant treatment. Risk of recurrence depends mostly on the presence of a risk factor for developing venous thromboembolism, with patients with unprovoked events being at the higher risk of recurrence. The risk of recurrence needs to be balanced with the risk of bleeding and the potential severity of these thrombotic and hemorrhagic events. In patients with an unprovoked venous thromboembolism who complete treatment for the acute (first 10 days) and post-acute phase of the disease (from day 10 to 3-6 months), decision has to be made regarding prolonged antithrombotic therapy to prevent recurrences. The main goal of extended treatment is preventing recurrences with a safe profile in terms of bleeding risk. Many therapeutic options are now available for these patients, including antiplatelet therapy with aspirin or direct oral anticoagulants. Moreover, apixaban and rivaroxaban at prophylactic doses have demonstrated efficacy in preventing recurrences with a low risk of bleeding

Predicting IR Personalization Performance using Pre-retrieval Query Predictors

Personalization generally improves the performance of queries but in a few cases it may also harms it. If we are able to predict and therefore to disable personalization for those situations, the overall performance will be higher and users will be more satisfied with personalized systems. We use some state-of-the-art pre-retrieval query performance predictors and propose some others including the user profile information for the previous purpose. We study the correlations among these predictors and the difference between the personalized and the original queries. We also use classification and regression techniques to improve the results and finally reach a bit more than one third of the maximum ideal performance. We think this is a good starting point within this research line, which certainly needs more effort and improvements

Three-dimensional volume rendering in computed tomography for evaluation of the temporomandibular joint in dogs

Based on computed tomography (CT) images, volume rendering was used to obtain a three-dimensional representation of data (3DVR). The aims of this study included: describing the bone anatomy of the temporomandibular joint (TMJ) of dogs; comparing the TMJs of each dog by skull type and age; comparing 3DVR images with three-standard-plane CTs; assessing soft tissues adjacent to the TMJ and assessing pathological cases. Multidetector computed tomography scans of bilateral TMJs of 410 dogs were observed. From a ventral view, slight displacements in the positions of the skulls were seen, whereas from a caudal view, differences in amplitude of the articular space were observed. Dolichocephalic and mesaticephalic dogs showed more similar TMJ features than brachycephalic dogs. The shape of the TMJ bones were irregular in dogs under 1 year old. The 3DVR images related to the three-standard-plane CT improved the overall comprehension of the changes in the articular space amplitude and condylar process morphology. The fovea pterygoidea, mandibular fossa and retroarticular process were perfectly shown. A better spatial situation of adjacent soft tissues was obtained. The 3DVR represents an ancillary method to the standard-plane CT that could help in the understanding of the anatomy and diagnoses of different pathologies of the TMJ in dogs

Multi-atlas label fusion by using supervised local weighting for brain image segmentation

La segmentación automática de estructuras de interés en imágenes de resonancia magnética cerebral requiere esfuerzos significantes, debido a las formas complicadas, el bajo contraste y la variabilidad anatómica. Un aspecto que reduce el desempeño de la segmentación basada en múltiples atlas es la suposición de correspondencias uno-a-uno entre los voxeles objetivo y los del atlas. Para mejorar el desempeño de la segmentación, las metodologías de fusión de etiquetas incluyen información espacial y de intensidad a través de estrategias de votación ponderada a nivel de voxel. Aunque los pesos se calculan para un conjunto de atlas predefinido, estos no son muy eficientes en etiquetar estructuras intrincadas, ya que la mayoría de las formas de los tejidos no se distribuyen uniformemente en las imágenes. Este artículo propone una metodología de extracción de características a nivel de voxel basado en la combinación lineal de las intensidades de un parche. Hasta el momento, este es el primer intento de extraer características locales maximizando la función de alineamiento de kernel centralizado, buscando construir representaciones discriminativas, superar la complejidad de las estructuras, y reducir la influencia de los artefactos. Para validar los resultados, la estrategia de segmentación propuesta se compara contra la segmentación Bayesiana y la fusión de etiquetas basada en parches en tres bases de datos diferentes. Respecto del índice de similitud Dice, nuestra propuesta alcanza el más alto acierto (90.3% en promedio) con suficiente robusticidad ante los artefactos y respetabilidad apropiada.The automatic segmentation of interest structures is devoted to the morphological analysis of brain magnetic resonance imaging volumes. It demands significant efforts due to its complicated shapes and since it lacks contrast between tissues and intersubject anatomical variability. One aspect that reduces the accuracy of the multi-atlasbased segmentation is the label fusion assumption of one-to-one correspondences between targets and atlas voxels. To improve the performance of brain image segmentation, label fusion approaches include spatial and intensity information by using voxel-wise weighted voting strategies. Although the weights are assessed for a predefined atlas set, they are not very efficient for labeling intricate structures since most tissue shapes are not uniformly distributed in the images. This paper proposes a methodology of voxel-wise feature extraction based on the linear combination of patch intensities. As far as we are concerned, this is the first attempt to locally learn the features by maximizing the centered kernel alignment function. Our methodology aims to build discriminative representations, deal with complex structures, and reduce the image artifacts. The result is an enhanced patch-based segmentation of brain images. For validation, the proposed brain image segmentation approach is compared against Bayesian-based and patch-wise label fusion on three different brain image datasets. In terms of the determined Dice similarity index, our proposal shows the highest segmentation accuracy (90.3% on average); it presents sufficient artifact robustness, and provides suitable repeatability of the segmentation results

Ichthyofauna of two streams in the high basin of the Samborombón River, Buenos Aires province, Argentina

Se estudió la ictiofauna de los arroyos Manantiales (35°02 34 S; 58°19 37 W) y El Portugués (35°04 16 S; 58°26 09 W), pertenecientes a la alta cuenca del río Samborombón, provincia de Buenos Aires, Argentina. Se brindó especial énfasis en la abundancia, riqueza específica, diversidad y distribución temporal a lo largo de un ciclo anual. Se capturaron 8.595 ejemplares, pertenecientes a 20 especies, 11 familias y 5 órdenes. El orden Characiformes fue el más representado con un total de 9 especies y una abundancia relativa de 72,5 %, seguido de los Siluriformes con 6 especies y una abundancia relativa de 16,9%. La riqueza específica en Manantiales fue de 20 especies, el índice de diversidad anual, 1,42 y el índice de uniformidad, 0,58. La riqueza específica en El Portugués fue de 17 especies, el índice de diversidad anual, 1,51 y el índice de uniformidad, 0,64. Se observaron diferencias en la composición específica de las especies dominantes. Los valores de diversidad son semejantes a los registrados en arroyos de la Pampasia y del sur de BrasilThe ichthyofauna of the Manantiales (35°0234S; 58°1937W) and El Portugués (35°0416S; 58°2609W) streams, both of them pertaining to the high basin of the Samborombón River, in the Province of Buenos Aires, Argentina, was studied. Abundance, specific richness, diversity and temporary distribution were considered throughout an annual cycle. The specific diversity between both streams was compared and the physical and chemical parameters of the environment analizad. In total 8595 specimens were captured, pertaining to 20 species, 11 families and 5 orders. The order Characiformes was the most widely represented with 10 species and a relative abundance of 50%, followed by the order Siluriformes with 6 species and a relative abundance of 30%. The specific richness in the Manantiales was of 20 species, the annual diversity index was 1.42 and the uniformity index was 0.58. The specific richness in El Portugués was of 17 species, the annual diversity index was 1.51 and the uniformity index was 0.64. Differences in the composition of dominant species were observed. The diversity values are similar to that recorded in Pampasia and southern Brazil streams.Fil: Fernández, Eduardo M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Ferriz, Ricardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bentos, Cristina Amelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lopez, Guillermo Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentin