Comment on "BCS superconductivity of Dirac fermions in graphene layers"

Comment on "BCS superconductivity of Dirac fermions in graphene layers" by N. B. Kopnin and E. B. Sonin [arXiv:0803.3772; Phys. Rev. Lett. 100, 246808 (2008)].Comment: 1.1 page

Kondo Quantum Criticality of Magnetic Adatoms in Graphene

We examine the exchange Hamiltonian for magnetic adatoms in graphene with localized inner shell states. On symmetry grounds, we predict the existence of a class of orbitals that lead to a distinct class of quantum critical points in graphene, where the Kondo temperature scales as $T_{K}\propto|J-J_{c}|^{1/3}$ near the critical coupling $J_{c}$, and the local spin is effectively screened by a \emph{super-ohmic} bath. For this class, the RKKY interaction decays spatially with a fast power law $\sim1/R^{7}$. Away from half filling, we show that the exchange coupling in graphene can be controlled across the quantum critical region by gating. We propose that the vicinity of the Kondo quantum critical point can be directly accessed with scanning tunneling probes and gating.Comment: 4.1 pages, 3 figures. Added erratum correcting exponent nu=1/3. All the other results remain vali

Superconducting states of pure and doped graphene

We study the superconducting phases of the two-dimensional honeycomb lattice of graphene. We find two spin singlet pairing states, s-wave and an exotic $p+ip$ that is possible because of the special structure of the honeycomb lattice. At half filling, the $p+ip$ phase is gapless and superconductivity is a hidden order. We discuss the possibility of a superconducting state in metal coated graphene.Comment: 4 pages, 6 figure

Electron-Electron Interactions in the Vacuum Polarization of Graphene

We discuss the effect of electron-electron interactions on the static polarization properties of graphene beyond RPA. Divergent self-energy corrections are naturally absorbed into the renormalized coupling constant $\alpha$. We find that the lowest order vertex correction, which is the first non-trivial correlation contribution, is finite, and about 30% of the RPA result at strong coupling $\alpha \sim 1$. The vertex correction leads to further reduction of the effective charge. Finite contributions to dielectric screening are expected in all orders of perturbation theory.Comment: 5 pages, 2 figures; published versio

Reconhecimento de forma tridimensional para um sistema de varrimento de um vibrómetro laser

Laser vibrometry is a technique that, among several possibilities, allows modal analysis of light and thin structures. To make this analysis possible, the capture of a set of points is initially necessary. The devices present in the market, besides being expensive, present a rudimentary obtaining of points, usually done manually by the user. Not presenting the flexibility required for research, it is planned in this project to develop a system of automatic acquisition of these points for a laser vibrometer scanner. Given this need, a system was created to capture points through the information acquired by a Microsoft Kinect camera. In a Matlab environment, these points were converted into point clouds and processed through an application, in which the user can define their final configuration. This work presents the results obtained during the analysis of two different types of geometries through the application developed.A vibrometria laser é uma técnica que, entre várias possibilidades, permite a realização de análises modais de estruturas leves e finas. Para tornar esta análise possível, a captura de um conjunto de pontos é inicialmente necessária. Os dispositivos presentes no mercado, para além de dispendiosos, apresentam uma obtenção de pontos rudimentar, normalmente feita de forma manual pelo utilizador. Não apresentando a flexibilidade exigida para investigação, está previsto neste projeto desenvolver um sistema de aquisição automático destes pontos para um scanner de um vibrometro laser. Dada esta necessidade, foi criado um sistema de captura de pontos através da informação adquirida por uma câmara da Microsoft Kinect. Num ambiente Matlab, estes pontos foram convertidos em nuvens de pontos e processados através de uma aplicação, na qual o utilizador pode definir a sua configuração final. Este trabalho apresenta os resultados obtidos durante a análise de dois tipos diferentes de geometrias através da aplicação desenvolvida.Mestrado em Engenharia Mecânic

Immigration Enforcement Within the United States

[From Introduction] An estimated 11 million unauthorized aliens reside in the United States, and this population is estimated to increase by 500,000 annually. Each year, approximately 1 million aliens are apprehended trying to enter the United States illegally. Although most of these aliens enter the United States for economic opportunities and family reunification, or to avoid civil strife and political unrest, some are criminals, and some may be terrorists. All are violating the United States’ immigration laws

Semilinear fractional differential equations: global solutions, critical nonlinearities and comparison results

In this work we study several questions concerning to abstract fractional Cauchy problems of order α ∈ (0, 1). Concretely, we analyze the existence of local mild solutions for the problem, and its possible continuation to a maximal interval of existence. The case of critical nonlinearities and corresponding regular mild solutions is also studied. Finally, by establishing some general comparison results, we apply them to conclude the global well-posedness of a fractional partial differential equation coming from heat conduction theory.Conselho Nacional de Desenvolvimento Científico e TecnológicoCoordenação de aperfeiçoamento de pessoal de nivel superiorFundação de Amparo à Pesquisa do Estado de São PauloMinisterio de EducaciónMinisterio de Ciencia e InnovaciónJunta de Andalucí

A Systematic Review

Jardim, B., & De Castro Neto, M. (2022). Walkability Indicators in the Aftermath of the COVID-19 Pandemic: A Systematic Review. Sustainability, 14(17), 1-24. [10933]. https://doi.org/10.3390/su141710933 - -----Funding: This research was funded by the Project C-TECH—Climate Driven Technologies for Low Carbon Cities, grant number POCI-01-0247-FEDER-045919 | LISBOA-01-0247-FEDER-045919, co-financed by the ERDF—European Regional Development Fund through the Operational Program for Competitiveness and Internationalization—COMPETE 2020, the Lisbon Portugal Regional Operational Program—LISBOA 2020 and by the Portuguese Foundation for Science and Technology—FCT under MIT Portugal Program. This work was also supported by Portuguese national funds through the Portuguese Foundation for Science and Technology—FCT under research grant FCT UIDB/04152/2020–Centro de Investigação em Gestão de Informação (MagIC).Walkability indicators are a pivotal method to evaluate the role of the built environment in people’s decisions regarding active mobility, contributing to help promote more sustainable and equitable regions. Currently, there is a lack of literature describing the trends and findings from recent studies, and how research on this topic has responded to COVID-19. In this work, we apply the PRISMA methodology to perform a systematic literature review of studies that employed walkability indicators to uncover associations between walkability and different topics, such as physical activity, health and mobility, in the aftermath of the pandemic. Results show that the growth rate of studies in this period almost doubled compared to the three years prior to the outbreak. We explore the main subjects addressed in recent literature and found that most studies resorted to well-known indicators, predominantly to Walk Score®, while fewer works developed and applied new indicators. General findings point to a positive association between walkability and physical activity, overall health and active mobility. Moreover, in recent works, walkability’s relationship with environmental metrics is not clear and there is a lack of studies linking walkability indicators to COVID-19. More than two years after the worldwide outbreak of the COVID-19 virus, our work provides an effective resource for researchers to understand recent trends in studies employing walkability indicators.publishersversionpublishe