Space dependent Fermi velocity in strained graphene

We resolve some apparent discrepancies between two different models for curved graphene: the one based on tight binding and elasticity theory, and the covariant approach based on quantum field theory in curved space. We demonstrate that strained or corrugated samples will have a space dependent Fermi velocity in either approach that can affect the interpretation of some experiments.Comment: Revised version as will appear in Phys. Rev. Let

Flow injection determination of readily assimilable nitrogen compounds during vinification

A flow injection method for the determination of readily assimilable nitrogen (r.a.n.), i.e. ammonium and aminated nitrogen, is reported. The difference in pH of the sample in the presence and absence of formaldehyde, which blocks the amino function, provides the value of r.a.n. by monitoring the changes in absorbance of bromothymol blue at 616 nm. The detection and quantification limits are 10 and 11.6 mg l-1, respectively; the reproducibility and repeatability are 3.94 mg l-1 and 1.35 mg l-1, respectively; and the sample throughput is 20 samples h-1. The method has been applied to the analysis of 120 samples of must and wine subjected to biological aging. The proposed method also provides good correlation with the reference method used in routine analysis, and it is faster and gives sufficient precision for wineries requirements

A general framework for nonholonomic mechanics: Nonholonomic Systems on Lie affgebroids

This paper presents a geometric description of Lagrangian and Hamiltonian systems on Lie affgebroids subject to affine nonholonomic constraints. We define the notion of nonholonomically constrained system, and characterize regularity conditions that guarantee that the dynamics of the system can be obtained as a suitable projection of the unconstrained dynamics. It is shown that one can define an almost aff-Poisson bracket on the constraint AV-bundle, which plays a prominent role in the description of nonholonomic dynamics. Moreover, these developments give a general description of nonholonomic systems and the unified treatment permits to study nonholonomic systems after or before reduction in the same framework. Also, it is not necessary to distinguish between linear or affine constraints and the methods are valid for explicitly time-dependent systems.Comment: 50 page

Anti-ganglioside antibodies in patients with Zika virus infection-associated Guillain-Barré Syndrome in Brazil.

Zika virus infection is associated with the development of Guillain-Barré syndrome (GBS), a neurological autoimmune disorder caused by immune recognition of gangliosides and other components at nerve membranes. Using a high-throughput ELISA, we have analyzed the anti-glycolipid antibody profile, including gangliosides, of plasma samples from patients with Zika infections associated or not with GBS in Salvador, Brazil. We have observed that Zika patients that develop GBS present higher levels of anti-ganglioside antibodies when compared to Zika patients without GBS. We also observed that a broad repertoire of gangliosides was targeted by both IgM and IgG anti-self antibodies in these patients. Since Zika virus infects neurons, which contain membrane gangliosides, antigen presentation of these infected cells may trigger the observed autoimmune anti-ganglioside antibodies suggesting direct infection-induced autoantibodies as a cause leading to GBS development. Collectively, our results establish a link between anti-ganglioside antibodies and Zika-associated GBS in patients

Encouraging Undergraduate Marketing Students to Reflect on Critical Thinking and the Digital Gender Divide

In today’s society where there is an abundance of accessible, complex, and often false information, critical thinking (CT) is an essential skill so that citizens in general and students in particular can make complex decisions based on scientific evidence, rather than on prejudices, biases, and pre-established beliefs. In this context, the purpose of this study is to discover whether Active Learning (AL) methodology, using different technologies, contributes to improving the CT of the student body, applying it to the Digital Gender Divide (DGD). Three questionnaires were used to collect information, using both a quantitative and a qualitative approach. Open-ended questions are included for fuller answers, which are complemented by content analysis of the recordings and virtual presentations made. The results show that the AL methodology favours the development of CT in the DGD in a remarkable way. Likewise, the various technologies implemented in the methodology (e.g., the Google Applications Site, online round table discussions, role-plays, virtual presentations, and forms) are relevant to improving CT in DGD. It concludes by recommending the implementation of AL with CT as in the one carried out, to help prepare better professionals and raise awareness of how to reduce the DGD

Ceramic dies selection for electrical resistance sintering of metallic materials

Processing metallic powders by electrical resistance sintering requires the use of insulating ceramics dies. Selecting the appropriate ceramic material according to the electrical, thermal and mechanical properties is a need. Dies produced with several ceramic materials have been tested during the production of cemented carbide in order to check their behaviour in the process and final product properties. Tialite/mullite, zircon/mullite, zirconium phosphate based ceramic, yttria-stabilized zirconia and sialon, in most cases with modified compositions and shaping processes in order to achieve a high density, have been tested. Dry powder processing by cold isostatic pressing and furnace sintering resulted to be the better process for dies production. The effect of die properties on the produced cemented carbide, and the behaviour and life of the die during the production have been analysed. Very smooth die surface increases the number of cycles withstood during metallic parts production, because of lower extraction stresses, as checked for sialon dies. Zirconium phosphate based dies, with low thermal conductivity, show the most densified hard metal parts surface.Pproject EFFIPRO (EU) FP7-2013-NMP-ICT-FoF GRANT AGREEMENT N° 6087

Charge inhomogeneities due to smooth ripples in graphene sheets

We study the effect of the curved ripples observed in the free standing graphene samples on the electronic structure of the system. We model the ripples as smooth curved bumps and compute the Green's function of the Dirac fermions in the curved surface. Curved regions modify the Fermi velocity that becomes a function of the point on the graphene surface and induce energy dependent oscillations in the local density of states around the position of the bump. The corrections are estimated to be of a few percent of the flat density at the typical energies explored in local probes such as scanning tunnel microscopy that should be able to observe the predicted correlation of the morphology with the electronics. We discuss the connection of the present work with the recent observation of charge anisotropy in graphene and propose that it can be used as an experimental test of the curvature effects.Comment: 9 pages, 5 figures. v2: Abstract and discussion about experimental consequences expande

Exploring the Shopping Motivations of International Residential Tourists

Over the last few decades, so-called “international residential tourism” has increased considerably, creating a new consumer base in tourist destinations, particularly in southern Europe, whose shopping motivations are unknown. As a rule, existing literature has focused its attention on studying consumer motivations in their places of residence, references to the study of the international residential tourist's (IRT's) shopping motivations being very limited. It is in this context that this study examines the main contributions related to IRT shopping motivations. Taking as a starting point empirical research carried out in two top international tourist destinations, the study analyzes and contrasts the applicability of general theoretical contributions to this specific IRT segment. The results obtained confirm the existence, although not without its variations, of certain stability in the main aspects relating to shopping motivation, allowing the foundations to be laid for the incorporation of shopping motivation as a variable for the segmentation of IRTs. Both for tourist resort managers and retailers in the area, having access to a valid scale for measuring these motivations may be of great help to them in being able to categorize IRTs in accordance with their shopping motivations. In this way, they will have a broader knowledge of the market and how it is made up and it will facilitate the implementation of marketing policies aimed at improving the planning of commercial areas, as well as help them to adapt their product range and communication to the segments that are of most interest to their companies and destinations.The authors would like to express their thanks for the financial support received under the MCYTFEDER Research Project, grant SEJ-2006-08342/ECON

First record of Pontederia cordata L. (Pontederiaceae) in southern Spain and risk assessment for Europe

Pontederia cordata L. (Pontederiaceae) is an emerging aquatic plant native to the American continent that has been introduced to various continents through longdistance commerce as an ornamental plant. Individuals growing in the wild belonging to Pontederia L. genus where found in South Spain. The analysis of diagnostic characters of the collected specimens and their comparison to those represented in herbarium vouchers allowed us to distinguish them from its closest relative, P. sagittata C. Presl and to assign all the specimens found at the locality to P. cordata L. This is the southernmost European record of the species. It was clear that the origin of the introduction was the use as ornamental aquatic plant in the area. Its invasion risk was assessed for Europe, firstly, by analysing the suitability of European climate for the species, secondly, by assessing the potential impact. Results showed that from 92.5 to 92.9% of the meteorological stations analysed showed climate conditions that were compatible with the species' climatic requirements. The ecological characteristics of the species and the climatic features of the area analysed suggest a great risk of invasion that could lead to the species' spread in Europe. These findings suggest that P. cordata could threaten European wetlands