Analysis of Different Methodologies to Calculate Bouguer Gravity Anomalies in the Argentine Continental Margin

We have tested and used two methods to determine the Bouguer gravity anomaly in the area of the Argentine continental margin. The first method employs the relationship between the topography and gravity anomaly in the Fourier transform domain using Parker’s expression for different orders of expansion. The second method computes the complete Bouguer correction (Bullard A, B and C) with the Fortran code FA2BOUG2. The Bouguer slab correction (Bullard A), the curvature correction (Bullard B) and the terrain correction (Bullard C) are computed in several zones according to thedistances between the topography and the calculation point. In each zone, different approximations of the gravitationalattraction of rectangular or conic prisms are used according to the surrounding topography. Our calculations show that the anomaly generated by the fourth order in Parker’s expansion is actually compatible with the traditional Bouguer anomaly calculated with FA2BOUG, and that higher orders do not introduce significant changes. The comparison reveals that the difference between both methods in the Argentine continental margin has a quasi bimodal statistical distribution. The main disadvantage in using routines based on Parker's expansion is that an average value of the topography is needed for the calculation and, as the margin has an abrupt change of the topography in the continental slope area, it causes a bimodal distribution. It is worth noticing that, as expected, the most important differences between both methods are located over the continental slope both in complex structures such as part of the shared margin, as well as in isolated points where there are contributions from short wavelength or rugged topography.Fil: Pedraza de Marchi, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Ghidella, Marta E.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Tocho, Claudia. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

Analysis of Different Methodologies to Calculate Bouguer Gravity Anomalies in the Argentine Continental Margin

We have tested and used two methods to determine the Bouguer gravity anomaly in the area of the Argentine continental margin. The first method employs the relationship between the topography and gravity anomaly in the Fourier transform domain using Parker’s expression for different orders of expansion. The second method computes the complete Bouguer correction (Bullard A, B and C) with the Fortran code FA2BOUG2. The Bouguer slab correction (Bullard A), the curvature correction (Bullard B) and the terrain correction (Bullard C) are computed in several zones according to thedistances between the topography and the calculation point. In each zone, different approximations of the gravitationalattraction of rectangular or conic prisms are used according to the surrounding topography. Our calculations show that the anomaly generated by the fourth order in Parker’s expansion is actually compatible with the traditional Bouguer anomaly calculated with FA2BOUG, and that higher orders do not introduce significant changes. The comparison reveals that the difference between both methods in the Argentine continental margin has a quasi bimodal statistical distribution. The main disadvantage in using routines based on Parker's expansion is that an average value of the topography is needed for the calculation and, as the margin has an abrupt change of the topography in the continental slope area, it causes a bimodal distribution. It is worth noticing that, as expected, the most important differences between both methods are located over the continental slope both in complex structures such as part of the shared margin, as well as in isolated points where there are contributions from short wavelength or rugged topography.Facultad de Ciencias Astronómicas y Geofísica

Healthy urban food

Food is a territorial system that is closely linked to public health, social equity, and land policies. Eating habits are at the root of both incidence of cardiovascular disease and the phenomenon of malnutrition. Food often entails social inequity and is acquiring, directly and indirectly, ever greater relevance in the tools of territorial governance. The Cities2030 project is being developed and financed by the European Horizon 2020 programme. The methodology agreed upon by the partners envisages the involvement of all interest groups and actors within the food system arena through the installation of urban Policy and Living Labs. The University Iuav of Venice is involved in the development of two labs in the Veneto region: one in the city of Vicenza, the other in the Venice lagoon. Working in these two labs will make it possible to reflect on two food systems which are very different even though they are geographically close

Controversies on Rituximab Therapy in Sjögren Syndrome-Associated Lymphoproliferation

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by chronic inflammation of salivary and lachrymal glands, and frequently accompanied by systemic symptoms. A subgroup of SS patients develops malignant B cell non-Hodgkin's lymphoma (NHL), usually of the mucosa-associated lymphoid tissue (MALT) type and very often located in the major salivary glands. Currently, there is a lack of evidence-based intervention therapy which may influence SS-related chronic inflammation and lymphoproliferation. B cells are involved in the pathogenesis of SS, and B cell downregulation may lead to a decrease of disease activity. Rituximab (RTX), a chimeric monoclonal antibody targeting the CD20 antigen on the B cell surface, has been successfully investigated in other autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, ANCA-associated vasculitis, and mixed cryoglobulinemic syndrome. Preliminary experiences of RTX therapy in SS patients with or without a lymphoproliferative disorder suggest that SS patients with more residual exocrine gland function might better benefit from RTX. Efficacy of RTX in SS-associated B-cell lymphoma, mainly in low-grade salivary gland lymphomas, remains an open issue

Pensare come una laguna. Verso un contratto di area umida per la laguna nord di Venezia

Il progetto Interreg Italia-Croazia CREW - Coordinated Wetland Management in Italy-Croatia cross-border region, si pone come obiettivo principale la tutela della biodiversità delle aree umide costiere nella regione adriatica tra Italia e Croazia, attraverso lo sviluppo di strumenti innovativi di governance partecipata, quale il Contratto di Area Umida. l’Università Iuav di Venezia, leader partner del progetto, ha scelto di occuparsi della Laguna di Venezia, area umida di grande rilevanza storica, culturale, economica ed ambientale a livello europeo e mediterraneo. Promuovendo la centralità dei soggetti territoriali (amministrazioni locali, comunità, associazioni e singoli) ma anche dei soggetti ‘diversamente animati’ (flora e fauna), il Contratto per la Laguna nord di Venezia si propone di affrontare la gestione delle aree umide superando i confini amministrativi e guardando agli ecosistemi nel loro complesso

3D Process-Oriented Gravity Modelling applied north of 49ºS on the Argentine continental margin

The Process-Oriented Gravity Modelling (POGM) technique represents a useful way to distinguish the contribution that different geological processes make to the observed gravity in passive margins. The POGM is an innovative gravity modelling approach that can give us information about the role that processes such as sedimentation and magmatic underplating, together with their loading effects, may play in the evolution of a margin. In this work, the POGM methodology has been applied with in a 2D and 3D approach. 2D profiles spaced every one arc-minute in the area of the Argentine continental margin, between 38.5°S and 49°S latitude and 64°W and 50°W longitude, were used to generate the latter. The 3D POGM was also solved and the result was compared with that obtained from 2D profiles. The comparison with the observed anomaly, using the 3D approach from 2D profiles gave results with enhanced resolution. The best fit between the calculated and observed gravity anomaly is given by an effective elastic thickness of 15 km. A cortical thickness map obtained as a result of the POGM calculations shows basin areas characterized by a thinned crust and a structural variation where the continental-oceanic boundary (COB) could be indicated. Besides, results of POGM allow us to detect an alignment between the Valdés and Rawson basins and possibly a third basin as a probable aulacogen. A stretching factor analysis shows that in these basins a stretching period existed but it did not reach the stage of oceanic crust formation. A strong positive residue in the Colorado basin is shown by the flexural isostatic anomaly, suggesting that the basin may continue in subsidence.Facultad de Ciencias Astronómicas y Geofísica

Anomalía de subplacado magmático en el perfil 43.5ºS del margen continental argentino

Los márgenes volcánicos de rift se caracterizan por ocurrencia masiva de volcanismo extrusivo e intrusivo (subplacado magmático) formado durante la ruptura de la litosfera continental (Hinz ,1981; White and Mckenzie, 1989). Recientes ilustraciones de la distribución global de estos márgenes revelan que ellos representan entre el 75-90% de los márgenes continentales pasivos (Eldholm et al., 2000). Hinz et al. (1999) muestran que el relativamente poco investigado margen argentino es de tipo volcánico. Según Thybo and Artemieva (2013), dentro de la definición de suplacado magmático entrarían un amplio rango de procesos y éste podría definirse como la “adición de magma máfico a la corteza inferior y parte superior del manto alrededor del Moho”. Uno de los aspectos más distintivos de la gravedad en zonas marinas es el efecto de borde de la anomalía de aire libre asociado con márgenes continentales pasivos y que generalmente, se atribuye a la transición entre la corteza continental y oceánica por sus diferentes espesores. La importancia del estudio de procesos reológicos, sedimentación, magmatismo y fenómenos de difusión del calor que modifican la estructura inicial de la corteza por un rift pueden ayudar a entender la característica distintiva del efecto de borde de la anomalía de gravedad en este tipo de márgenes. Una manera útil de lograr esto es a través del “modelado de gravedad orientado por los procesos” (POGM, por sus siglas en inglés) donde cada proceso geológico está asociado a una anomalía. Estas anomalías son: la anomalía del rift, la de la sedimentación y la del subplacado magmático (Watts y Fairhead, 1999). El interés de este trabajo se centra en la anomalía de gravedad producida por el subplacado magmático rara vez investigada en perfiles reales y en particular en el margen argentino, debido principalmente a la falta de acceso a datos de sísmica de refracción. La anomalía del subplacado magmático puede verse como la contribución a la anomalía de gravedad del proceso geológico “subplacado magmático”. Hemos modelado este efecto considerando valores de densidades estándares e interpretadas por Schnabel et al. (2008) para un rango variable de espesores elásticos. Los resultados obtenidos dan un máximo levantamiento flexural asociado con este efecto, que es 145 m y 276 m para densidades del cuerpo subplacado de 3050 kg/m3 y 3150 kg/m3 respectivamente y una densidad promedio de los sedimentos de 2300 kg/m3. La principal conclusión de la incorporación del cálculo del efecto del subplacado en el POGM es el aumento de espesor elástico (25 km) para un error medio cuadrático (rms) mínimo en comparación con el cálculo realizado sin considerar el subplacado magmático (20 km), asociado con el engrosamiento de la corteza (Watts, 2001). La anomalía del subplacado presenta contribuciones opuestas para los casos Airy y Flexural como fuera señalado por Watts y Fairhead (1999).Eje: Estudio del Interior Terrestre.Facultad de Ciencias Astronómicas y Geofísica