Curvature of a class of indefinite globally framed ff-manifolds

We present a compared analysis of some properties of indefinite almost $\mathcal{S}$-manifolds and indefinite $\mathcal{S}$-manifolds. We give some characterizations in terms of the Levi-Civita connection and of the characteristic vector fields. We study the sectional and ${\phi}$-sectional curvature of indefinite almost $\mathcal{S}$-manifolds and state an expression of the curvature tensor field for the indefinite $\mathcal{S}$-space forms. We analyse the sectional curvature of indefinite $\mathcal{S}$-manifold in which the number of the spacelike characteristic vector fields is equal to that of the timelike characteristic vector fields. Some examples are also described.Comment: 17 pages, no figure

Consent notices and cognitive cost after the GDPR : an experimental study

In May 2018, the European Union enforced the General Data Protection Regulation (GDPR). This regulation makes mandatory to recover user’s consent when they access a website, thus firms have to implement cookie banners that allow users to declare their privacy preferences. The aim of this paper is to study users’ interaction with four different banners that combine the opt-in/opt-out format with the presence or not of a bulk option (Accept/Reject all button). It analyzes how users react to the introduction of such bulk option that decrease cognitive cost to interact with banners. This study finds that the bulk option has an impact on user’s interaction with the banners, especially when combined with the opt-in format (p<0.001). This study also finds that without the bulk option, the format has no impact on interaction. Moreover, with the bulk option, users’ interaction is the same no matter the default option for the EU population since the presence of the “Accept/Reject all” buttons induce people to click on them even though they represent two opposed decisions over data provision. However, when comparing the EU and the US samples, the results highlight a lower interaction due to the opt-out format (p<0.001) in presence of the bulk option. This study contributes to the scientific research regarding the effects of GDPR on users’ online behavior and it participates to the debate on the regulatory environment of online personal information.Em maio de 2018, a União Europeia implementou o Regulamento Geral de Proteção de Dados (GDPR). Este regulamento torna obrigatória a recuperação do consentimento do usuário ao aceder um site. Portanto, as empresas precisam implementar banners de cookies que permitam aos usuários de declarar as suas preferências relacionadas à privacidade. O objetivo deste documento é estudar a interação do usuário com quatro tipos diferentes de banners que combinam o opt-in/opt-out format com a presença ou não de bulk option (Aceitar/Rejeitar todos os botões). O mesmo, analisa como os usuários reagem com a introdução deste bulk option que reduz o custo cognitivo para interagir com os banners, especialmente quando combinado com o formato opt-in (p<0.01). O presente estudo também conclui que sem o bulk option, o formato não tem nenhum impacto na interação. Além disso, com o bulk option, a interação do usuário é a mesma, independente da default option para a população europeia, enquanto a presença dos botões de “Aceitar/Rejeitar tudo” induz as pessoas a clicarem neles apesar de representar duas decisões opostas sobre o fornecimento de dados. Contudo, ao comparar as amostras da UE e dos EUA, os resultados evidenciam uma menor interação devido ao formato opt-out (p<0.001) em presença do bulk option. Este estudo contribui para a pesquisa científica com os efeitos do GDPR no comportamento online dos usuários e participa ao debate sobre o ambiente regulatório das informações pessoais

FDI potential and shortfalls in the MED AND CEECS: determinants and diversion effects

This paper examines FDI flows (1994-2004) from the EU (and for comparison from the USA and Japan) to two neighbouring regions: Central and Eastern Europe (CEE) and South Mediterranean (MED) countries. The analysis provides circumstantial evidence that the intensification of FDI in CEE, following integration within the EU, has had no discernible dampening effect on FDI flows directed to MED countries. This hypothesis is confirmed in several empirical analyses. First, a random effect gravity regression for determinants of bilateral FDI flows to a large sample of 84 developed and developing partners shows that when environmental, institutional and policy variables are included in the analysis MED countries are not different from the rest of the sample. Moreover, the actual capital inflow to MED economies is not much far from the flow predicted based on the enlarged gravity equation. This suggests that the low inflow of FDI to the region might correspond to equilibrium condition considering various distortions that economic agents have to face in MED countries. This result is also confirmed by the common trend followed by coefficients obtained interacting yearly with regional dummies for the two areas

A national student survey for the Italian higher education system

Despite the strong criticisms, mass student surveys play an important role in the quality assurance process of national higher education systems. While some national higher education systems have a long history of using student surveys to inform teaching and course quality improvement (e.g. the UK, Australia), in Italy, where the quality assurance system has been put in place at both state and institutional levels, a national student survey has never been implemented. As a consequence, higher education institutions have used, and still use, only student evaluations of teaching. If, on the one hand, these local surveys tend to overlap with the rationale and structure of a national survey, on the other hand, they prevent universities from comparing quality indicators. Given the strong drive to use student surveys as a quality assurance mechanism, the present article reports a study aimed to design and probe a new questionnaire to be used at the national level. A total of 572 final year students enrolled in a public university participated in the study. Data were examined using a principal component analysis. Study results could set the groundwork for a critical debate on changes and improvements in the quality assurance process

Antioxidant Activity of Free and Bound Compounds in Quinoa (Chenopodium quinoa Willd.) Seeds in Comparison with Durum Wheat and Emmer

Antioxidant activity (AA) of quinoa (Chenopodium quinoa Willd.) seeds, as well as of durum wheat (Triticum turgidum L. ssp. durum Desf.) and of emmer (T. turgidum L. ssp. dicoccum Sch¨ubler) grains, was evaluated by studying hydrophilic (H), lipophilic (L), free-soluble (FSP) and insoluble-bound (IBP) phenolic extracts using the new lipoxygenase/4-nitroso-N,N-dimethylaniline (LOX/RNO) method, able to simultaneously detect different antioxidant mechanisms, as well as using the Oxygen Radical Absorbance Capacity (ORAC) and the Trolox Equivalent Antioxidant Capacity (TEAC) assays, which measure the scavenging activity against peroxyl and ABTS [2,2-azino-bis-(3- ethylbenzothiazoline-6-sulfonate)] radicals, respectively. The species under study were compared with respect to the sum of AA values of H, L and FSP extracts (AAH+L+FSP), containing freely solvent-soluble antioxidants, and AA values of IBP extracts (AAIBP), representing the phenolic fraction ester-linked to insoluble cell wall polymers. The LOX/RNO and ORAC methods measured in quinoa flour a remarkable AAH+L+FSP higher than durum wheat, although lower than emmer; according to the same assays, the IBP component of quinoa resulted less active than the durum wheat and emmer ones. The TEAC protocol also revealed a high AAH+L+FSP for quinoa. Interestingly, the ratio AAH+L+FSP/AAH+L+FSP+IBP, as evaluated by the LOX/RNO and ORAC assays, resulted in quinoa higher than that of both durum wheat and emmer, and much higher than durum wheat, according to the TEAC protocol. This may suggest that antioxidants from quinoa seeds may be more readily accessible with respect to that of both the examined wheat species

K-manifolds locally described by Sasaki manifolds

AbstractK-manifolds are normal metric globally framed f-manifolds whose Sasaki 2-form is closed. We introduce and study some subclasses of K-manifolds. We describe some examples and we also state local decomposition theorems