Inventorying geological heritage in vast territories: first proposal for Paraná State, Brazil

Brazil has an area of 8,514,876 square kilometres, occupying almost half (47%) of the area of South America. This territory shows an exceptional geodiversity resulting from a great variety of geological materials, geoforms and processes. The concept of geoconservation in Brazil is relatively new, what makes incentives and investments in research in this area necessary. However, the vast dimension of Brazilian territory makes the task of studying and implementing strategies to ensure the conservation of the national geological heritage rather difficult. Therefore, the best way to initiate the studies of the Brazilian geoheritage would be by starting from the 26 Federated States, which are political and administrative subdivisions of Brazil. The ideal strategy would be to direct the efforts, firstly to the definition of geological frameworks and their more representative geosites for each State and lately, carry out the correlation with the categories at national level. This approach is being conducted in many European countries following the recommendations of ProGEO (www.progeo.se). Based on this proposition, a proposal to make a systematic inventory of the geological heritage of Paraná State is being developed, in order to establish a scientific basis which will allow the study and protection of geosites at the state, country and international levels. This work is based on a consensus of ideas with the support of the geoscientific community in Paraná. Paraná State is located in the South of Brazil and has an area of 199,314,850 square kilometres. The geological history of the territory of Paraná State started more than 2,8 million years ago, although discontinuous. The geosites inventory is based on the establishment of criteria to select the frameworks and the geosites which represent these frameworks. For a particular item of a geological process or product to be selected as a framework in the context of the Paraná State, it must be representative and there must be a certain degree of scientific knowledge about it. Following the same reasoning that each geosite will materialize a certain framework, it must be representative in the framework and have integrity. Geosites may also present other less important features, not presenting selective capacity, such as: rarity, diversity of elements of geological interest and association with other elements (ecological, cultural, archaeological, etc). In a preliminary geological assessment of the Paraná State the following frameworks can be highlighted: Archean, Paleoproterozoic and Neoproterozoic in the Paraná: metamorphism and tectonics; Serra do Mar; Volcanic sedimentary and sedimentary restricted basins; Tectonic structure of Ponta Grossa Arc; Devonian-Permian in the Paraná basin; Paleozoic Fossils; Carboniferous?Lower Permian in the Paraná basin; Jurassic-Cretaceous of Paraná basin; Guarany Aquifer; and Middle-Upper Cretaceous of the Paraná basin

The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission

Numerical calculations based on the recursive Green's functions method in the tight-binding approximation are performed to calculate the dimensionless conductance $g$ in disordered graphene nanoribbons with Gaussian scatterers. The influence of the transition from short- to long-ranged disorder on $g$ is studied as well as its effects on the formation of a perfectly conducting channel. We also investigate the dependence of electronic energy on the perfectly conducting channel. We propose and calculate a backscattering estimative in order to establish the connection between the perfectly conducting channel (with $g=1$) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.

Compact beam-steerable lens antenna for 60-GHz wireless communications

WOS:000270723500012 (Nº de Acesso Web of Science)This paper presents a new concept of steerable beam antenna composed by a dielectric lens which pivots in front of a single stationary moderate gain feed. The lens not only allows steering mechanically the beam in elevation and full azimuth, but further increases the gain up to 21 dBi. The solution is broadband, including the entire international unlicensed spectrum from 57 GHz to 66 GHz. A fabricated prototype shows the possibility of tilting the beam from - 45deg to + 45deg for all azimuths with gain scan loss below 1.1 dB and radiation efficiency above 95%. The arrangement is very simple, it does not require rotary joints, it is low cost and compact, lens plus feed volume being of the order of 3 times 3 times 3 cm3 with lens weight less than 10 g

Structure and dynamics of the supercluster of galaxies SC0028-0005

According to the standard cosmological scenario, superclusters are objects that have just passed the turn around point and are collapsing. The dynamics of very few superclusters have been analysed up to now. In this paper we study the supercluster SC0028-0005, at redshift 0.22, identify the most prominent groups and/or clusters that make up the supercluster, and investigate the dynamic state of this structure. For the membership identification, we have used photometric and spectroscopic data from SDSS-DR10, finding 6 main structures in a flat spatial distribution. We have also used a deep multi-band observation with MegaCam/CFHT to estimate de mass distribution through the weak-lensing effect. For the dynamical analysis, we have determined the relative distances along the line of sight within the supercluster using the Fundamental Plane of early-type galaxies. Finally, we have computed the peculiar velocities of each of the main structures. The 3D distribution suggests that SC0028-005 is indeed a collapsing supercluster, supporting the formation scenario of these structures. Using the spherical collapse model, we estimate that the mass within $r = 10$~Mpc should lie between 4 and $16 \times 10^{15} M_\odot$. The farthest detected members of the supercluster suggest that within $\sim 60$~Mpc the density contrast is $\delta \sim 3$ with respect to the critical density at $z=0.22$, implying a total mass of $\sim 4.6$--$16 \times 10^{17} M_\odot$, most of which in the form of low-mass galaxy groups or smaller substructures.Comment: 12 pages, 9 figures, Accepted for publication in MNRA

Evaluation of a new wideband slot array for MIMO performance enhancement in indoor WLANs

WOS:000289205200016 (Nº de Acesso Web of Science)“Prémio Científico ISCTE-IUL 2012”A new wideband compact slot antenna array for indoor WLAN access points (AP) is described, covering several wireless communication services from 2.4 to 4.8 GHz, that is especially designed to enhance MIMO system capacity. The array topology provides both spatial and polarization diversity. Despite very close packing of the array elements, these exhibit very low mutual coupling and low cross-polarization, greatly favoring MIMO diversity gain. A detailed MIMO performance comparison is conducted against a common array of patches in indoor environment, based both on simulation and indoor measurements: the new antenna shows a clear improvement in terms of channel capacity