Effects of Lorentz invariance violation on cosmic ray photon emission and gamma ray decay processes

In this work, we use Lorentz invariance violation (LIV) introduced as a generic modification to particle dispersion relations to study some consequences of single photon emission, known as vacuum Cherenkov radiation, and photon decay processes in cosmic and gamma rays. These processes are forbidden in a Lorentz invariant theory but allowed under the hypothesis of LIV. We show that the emission rate have a dependency on the cosmic ray primary mass and the electric charge that could modify the UHECR spectrum. Furthermore, LIV dramatically enhances photon decay into an electro-positron pair above certain energy threshold. This last effect can then be used to set limits to the LIV energy scale from the direct observation of very high energy cosmic photon events by telescopes of gamma-rays.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan, Kore

Assessment of crystallographic influence on material properties of calcite brachiopods

Calcium carbonate biominerals are frequently analysed in materials science due to their abundance, diversity and unique material properties. Aragonite nacre is intensively studied, but less information is available about the material properties of biogenic calcite, despite its occurrence in a wide range of structures in different organisms. In particular, there is insufficient knowledge about how preferential crystallographic orientations influence these material properties. Here, we study the influence of crystallography on material properties in calcite semi-nacre and fibres of brachiopod shells using nano-indentation and electron backscatter diffraction (EBSD). The nano-indentation results show that calcite semi-nacre is a harder and stiffer (H {approx} 3–5 GPa; E = 50–85 GPa) biomineral structure than calcite fibres (H = 0.4–3 GPa; E = 30–60 GPa). The integration of EBSD to these studies has revealed a relationship between the crystallography and material properties at high spatial resolution for calcite semi-nacre. The presence of crystals with the c-axis perpendicular to the plane-of-view in longitudinal section increases hardness and stiffness. The present study determines how nano-indentation and EBSD can be combined to provide a detailed understanding of biomineral structures and their analysis for application in materials science

Estructura del cinturón de pliegues y cabalgamientos de Peralta, República Dominicana

Most of the geotectonic units involved in the evolution of the Northern part of the Caribbean Plate can be identified in a geological cross-section through the southern-central part of the Hispaniola Island (South of the Dominican Republic). The cross-section includes from N to S: remnants of the old Caribbean ocean (Loma Caribe Peridotites and Duarte Fm of Upper Jurassic-Lower Cretaceous age), rocks of the Primitive volcanic Island Arc (Lower Cretaceous), the Circum-Caribbean Island Arc (Upper Cretaceous to Eocene), the Peralta thrust and fold Belt and the Azua Neogene Basin. The structure consists of an imbricate thrust system with associated folds, vergent towards the South, that overthrusts the Azua Basin. The thrust system evolved in a forward propagating sequence. The first thrust sheets of the Circum-Caribbean Island Arc possibly formed in Upper Eocene times during sedimentation of the Ocoa Fm in the foredeep (area of the Peralta Belt). Ocoa Fm has a syntectonic character and is associated with the uplift of the Central Mountain Range. Thrusting continued through Oligocene times progressing towards the South. By Lower Miocene times, the Circum-Caribbean Island Arc overthrusts the Peralta Belt (Frontal Thrust of the Tireo Fm). Thrusting in the Peralta Belt continued until Plio-Pleistocene times, as indicated by the age of the rocks in the footwall to the Peralta Belt Frontal Thrust. From Miocene times thrusting was coeval with wrenching that progressively became the dominant tectonic style in the region. The Eocene-Oligocene sedimentary sequences of the Peralta Belt were deposited in a back-arc basin that was subsequently deformed during the change in subduction direction that took place in the northeastern part of the Caribbean Plate in Neogene times. The Neogene Peralta Thrust and Fold Belt may be caused by the indentation of the Beata Ridge into the Circum-Caribbean Island Arc. In this context, the eastern part of the Beata Ridge may have acted as a transform boundary separating the Los Muertos trench from the Peralta Belt. The Peralta Belt accumulated part or all the shortening laterally equivalent to that in Los Muertos accretionary prism

Key issues in computational geomechanics

As stated in the introduction, the three main topics covered in this report are actual research fields. Different analyses and new developments related with these fields have been presented in the previous chapters. In the following, after a brief summary of the contributions, some directions for future research are outlined. Detailed presentations of the conclusions of each contribution are included in the corresponding sections and subsections. The most relevant contributions of this report are the following: 1. With respect to the treatment of large boundary displacements: > Quasistatic and dynamic analyses of the vane test for soft materials using a fluid–based ALE formulation and different non-newtonian constitutive laws. > The development of a solid–based ALE formulation for finite strain hyperelastic–plastic models, with applications to isochoric and non-isochoric cases. 2. Referent to the solution of nonlinear systems of equations in solid mechanics: > The use of simple and robust numerical differentiation schemes for the computation of tangent operators, including examples with several non-trivial elastoplastic constitutive laws. > The development of consistent tangent operators for substepping time–integration rules, with the application to an adaptive time–integration scheme. 3. In the field of constitutive modelling of granular materials: > The efficient numerical modelling of different problems involving elastoplastic models, including work hardening–softening models for small–strain problems and density– dependent hyperelastic–plastic models in a large–strain context. > Robust and accurate simulations of several powder compaction processes, with detailed analysis of spatial density distributions and verification of the mass conservation principle

Cut cotorsion pairs

We present the concept of cotorsion pairs cut along subcategories of an abelian category. This provides a generalization of complete cotorsion pairs, and represents a general framework to find approximations restricted to certain subcategories. We also exhibit some connections between cut cotorsion pairs and Auslander-Buchweitz approximation theory, by considering relative analogs for Frobenius pairs and Auslander-Buchweitz contexts. Several applications are given in the settings of relative Gorenstein homological algebra, chain complexes and quasi-coherent sheaves, but also to characterize some important results on the Finitistic Dimension Conjecture, the existence of right adjoints of quotient functors by Serre subcategories, and the description of cotorsion pairs in triangulated categories as co-$t$-structures.Comment: 48 page

Free Form of the Foldy-Wouthuysen Transformation in External Electromagnetic Fields

We derive the exact Foldy-Wouthuysen transformation for Dirac fermions in a time independent external electromagnetic field in the basis of the Ritus eigenfunctions, namely the eigenfunctions of the operator $(\gamma \cdot \Pi)^2$, with $\Pi^\mu = p^\mu - e A^\mu$. In this basis, the transformation acquires a free form involving the dynamical quantum numbers induced by the field.Comment: 8 pages. Accepted in J. Phys. A: Math. and Theo. (Fast Track Communication

Metamorfismo y estructura de la Formación Maimón y los Complejos Duarte y Río Verde, Cordillera Central Dominicana: implicaciones en la estructura y la evolución del primitivo Arco Isla Caribeño

The mainly metabasaltic pre-Aptian/Albian basement of the Median Belt of Hispaniola includes the Duarte Complex, the Río Verde Complex and the Maimón-Los Ranchos Formations. In base to mineral assemblages present in metabasic rocks and P-T conditions estimated from thermobarometry, the Río Verde Complex is divided into four metamorphic zones and Zone IV is further subdivided into two. The metamorphic grade increase upward in the structural sequence, from prehnite-pumpellyte facies (Zone I), through greens-chist facies (Zones II and III) and amphibolite facies (Zone IVa), to upper amphibolite facies (Zone IVb), only restricted to Cpx-bearing amphibolites just below the contact with the overlying Loma Caribe Peridotite. The metamorphic field gradient is inverse and of low-P type. The P-T paths documented for Zones IVa and IVb of the Río Verde Complex involve a two-stage prograde evolution: a first event of near isobaric heating in the low-pressure field, typical of sub-ophiolite metamorphic sole rocks and characterized by critical high-grade assemblages; and a second event marked by a medium-pressure overprint of the first-stage metamorphic assemblages following a high-P gradient. These P-T paths are interpreted to result from intra-oceanic thrusting during the closure of a back-arc basin related with the Primitive Caribbean Island Arc and the onset of subduction of arc units in the Aptian/Albian time, which formed the high-pressure metamorphic overprint. The heating and development of an inverted metamorphic gradient in the sub-ophiolite Río Verde Complex, can be genetically related with the hanginwall emplacement of the hot peridotitic slice and the conductive heat transfer downward. The studied sector of the Duarte Complex (metamorphosed oceanic plateau) is divided into three metamorphic zones. Their distribution suggest that there is a temperature increase westward and downward in the structural sequence, from the upper greenschist facies (zone A), through Ep-amphibolite and amphibolite facies (zone B), to upper amphibolite transitional to lower granulite facies (zone C). The metamorphic field gradient is normal and the mid-P type (25-30º C/km). The lowest structural levels of the complex are occupied by the gabro-norites of the La Jautía batholith, which formed in ductile shear zones Grt+Opx-bearing granulites metamorphic assemblages. The 89 Ma date obtained from foliated tonalites (U-Pb in zircons) established an Upper Cretaceous age for the main ductile shearing deformation. However, the deformation is very heterogeneous in the complex, existing regionally wide metamorphic sectors without related foliation development. Therefore, the prograde metamorphism of the Duarte Complex is interpreted to result from moderated thickening of a previously thick oceanic crust, due to the great accumulation of plateau-basalts (30 km). The post-thermal peak P-T paths suggest the unloading and cooling of the complex, during the continuous retrograde development of deformative and mylonitic non-coaxial Sp fabrics (84,6±0,5 Ma; 40 Ar/39 Ar cooling age in syn-Sp muscovite). In summary, the metamorphic rocks of the pre-Aptian/Albian basement units of the Median Belt record different stages in the history of the acretion-obduction of the Duarte plateau with the Caribbean Primitive Island Arc. All these tectonothermal events pre-date the final arc-continent collision between the Caribbean island arc and the Bahamas platform during the Late Cretaceous

Development of an open sensorized platform in a smart agriculture context: A vineyard support system for monitoring mildew disease

In recent years, some official reports, to produce best products regarding quality, quantity and economic conditions, recommend that the farming sector should benefit with new tools and techniques coming from Information and Communications Technology (ICT) realm. In this way, during last decade the deployment of sensing devices has increased considerably in the field of agriculture. This fact has led to a new concept called smart agriculture, and it contemplates activities such as field monitoring, which offer support to make decisions or perform actions, such as irrigation or fertilization. Apart from sensing devices, which use the Internet protocol to transfer data (Internet of Things), there are the so-called crop models, which are able to provide added value over the data provided by the sensors, with the aim of providing recommendations to farmers in decision-making and thus, increase the quality and quantity of their production. In this scenario, the current work uses a low-cost sensorized platform, capable of monitoring meteorological phenomena following the Internet of Things paradigm, with the goal to apply an alert disease model on the cultivation of the vine. The edge computing paradigm is used to achieve this objective; also our work follows some advances from GIScience to increase interoperability. An example of this platform has been deployed in a vineyard parcel located in the municipality of Vilafamés (Castelló Spain)

Subdivisión geoquímica del Arco Isla Circum-Caribeño, Cordillera Central Dominicana: Implicaciones para la formación, acrecion y crecimineto cortical en un ambiente intraoceánico

The Upper Cretaceous-Eocene Circum-Caribbean island-arc system (AICC) is a complex collage of crustal units or terranes s.l. which have formed and accreted within an intra-oceanic environment since Late Jurassic-Early Cretaceous times. In the Cordillera Central of the Dominican Republic these terranes are represented by several tectonostratigraphic units, that define a pre-Aptian-Albian deformed and metamorphosed basement, over and into which the igneous rocks of the AICC were extruded or intruded. Basement sequences can be subdivided into: (1) a plume-related Duarte terrane (plateau I); (2) a primitive arc-related Maimón-Amina terrane, which includes intra- or back-arc N-MORB units (Río Verde Complex) with a subduction geochemical imprint; and (3) the Loma Caribe peridotite terrane of mantle provenance. Two successive stages of the arc growth are superposed: an Early Cretaceous arc tholeiite stage with boninitic affinities (arc I), and a Late Cretaceous-Eocene calc-alkaline stage (AICC; arc II). The arc I stage is not recorded in the Duarte terrane but is represented in the Maimón-Amina terrane by the Río Verde Complex, the Maimón Forma-tion and the Peralvillo Norte Formation. In the Duarte terrane, the arc II growth stage include the Siete Cabezas Formation (Cenomanian- Maastrichtian, plateau II) and the fill of an intra-arc basin by the Tireo Formation (Cenomanian-Maastrichtian). In the Maimón-Amina terrane, the arc II growth is represented by the Las Lagunas and Peralvillo Sur Formations. The former lies unconformably on rudist-bearing limestone of Albian age (Hatillo Limestone). The Jautía gabbro-norite batholith and the calc-alkaline foliated and non-foliated tonalitic plutons of Late-Cretaceous-Early Eocene age intrude the rocks of the Duarte terrane except the Siete Cabezas Formation. Deformation and metamorphism of the pre-Aptian-Albian basement is a consequence of the collision of the Duarte plateau terrane with the Caribbean primitive island arc (Maimón-Amina terrane), that caused the emplacement of the Duarte terrane with a fragment of oceanic lithosphere (ophiolite). The interpretation of the geological and geochemical data support a tectonomagmatic model, which relates the compositional evolution of the intruded and extruded magmas in this segment of the AICC, with a flip in the subduction polarity under the primitive arc after the Aptian/Albian collision