Optical implementability of the two-dimensional Quantum Walk

We propose an optical cavity implementation of the two-dimensional coined quantum walk on the line. The implementation makes use of only classical resources, and is tunable in the sense that a large number of different unitary transformations can be implemented by tuning some parameters of the device.Comment: 9 pages, 3 figure

On the Anthropocene formalization and the proposal by the Anthropocene Working Group

In the coming years the Anthropocene will be likely submitted to formalization by the Anthropocene Working Group as a chronostratigraphic unit of the Geologic Time Scale. This has generated an increasing debate among detractors and defenders of its formalization in general, and of the proposal by the Anthropocene Working Group in particular. Here, the main issues regarding the Geologic Time Scale and the rules to formalize units, the empirical data supporting the Anthropocene formalization and the critiques to formalize it are critically reviewed. The procedure to formalize the Anthropocene is not dissimilar from those of the other units of the Geologic Time Scale and has been essentially based on stratigraphic and geologic criteria. Following the recommendation of the Anthropocene Working Group and based on the empirical evidence on the Anthropocene as it is expressed in strata and, more important, on the immanent and structural link between the Anthropocene and the reproduction of capital, it is proposed to define Capitalian as a Stage of the Anthropocene Epoch. In this way, a truly comprehensive understanding of the Earth history is obtained, which comprises the ultimate causes of the ongoing planetary transformation and its stratatigraphic expression

Van der Waals spin valves

We propose spin valves where a 2D non-magnetic conductor is intercalated between two ferromagnetic insulating layers. In this setup, the relative orientation of the magnetizations of the insulating layers can have a strong impact on the in-plane conductivity of the 2D conductor. We first show this for a graphene bilayer, described with a tight-binding model, placed between two ferromagnetic insulators. In the anti-parallel configuration, a band gap opens at the Dirac point, whereas in the parallel configuration, the graphene bilayer remains conducting. We then compute the electronic structure of graphene bilayer placed between two monolayers of the ferromagnetic insulator CrI$_3$, using density functional theory. Consistent with the model, we find that a gap opens at the Dirac point only in the antiparallel configuration.Comment: 5 pages, 4 figure

A Case Study in eGovernment Solutions

This work examines a challenge faced by governments in implementing private sector delivery solutions. More specifically, an inherent problem when attempting to shift government services provided at traditional point-of-sale facilities to alternative delivery channels, such as kiosks or through the internet, is studied. It is shown that while technical solutions, such as internet applications, can be readily developed to achieve a desired business objective, the non-technical operational aspects such as payment structure, customer expectations and acceptance, and marketing have a larger role in determining success. The experiences of the California Department of Motor Vehicles are used as an example in this paper. The department’s funding and cost recovery challenges in implementing internet based solutions are discussed. Actual measurement output data from the department are presented

Probing QCD approach to thermal equilibrium with ultrahigh energy cosmic rays

The Pierre Auger Collaboration has reported an excess in the number of muons of a few tens of percent over expectations computed using extrapolation of hadronic interaction models tuned to accommodate LHC data. Very recently, we proposed an explanation for the muon excess assuming the formation of a deconfined quark matter (fireball) state in central collisions of ultrarelativistic cosmic rays with air nuclei. At the first stage of its evolution the fireball contains gluons as well as $u$ and $d$ quarks. The very high baryochemical potential inhibits gluons from fragmenting into $u \bar u$ and $d \bar d$, and so they fragment predominantly into $s \bar s$ pairs. In the hadronization which follows this leads to the strong suppression of pions and hence photons, but allows heavy hadrons to be emitted carrying away strangeness. In this manner, the extreme imbalance of hadron to photon content provides a way to enhance the muon content of the air shower. In this communication we study theoretical systematics from hadronic interaction models used to describe the cascades of secondary particles produced in the fireball explosion. We study the predictions of one of the leading LHC-tuned models QGSJET II-04 considered in the Auger analysis.Comment: 7 pages LaTeX, 6 .pdf figure

Health Education from an Ecological Perspective. Adaptation of the Bronfenbrenner Model from an Experience with Adolescents

AbstractHealth requires the use of conceptual frameworks in order to understand it in its entirety and all its complexity. The ecological model of Bronfenbrenner is presented as a tool to collect the different variables involved in the conceptualisation of health.The research shows health discourses and lifestyles referred to by a group of adolescents from an ecological, salutogenic and cross-cultural perspective in order to build health education models derived from their own worldviews.To achieve this aim, photovoice was used as a methodological tool and the results were analysed using the qualitative data analysis program Atlas-Ti 7.The results show an adaptation of Bronfenbrenner's ecological model that stems from its application on speeches on health

Environmental Tobacco Smoke Exposure in Relation to Family Characteristics, Stressors and Chemical Co-Exposures in California Girls.

Childhood environmental tobacco smoke (ETS) exposure is a risk factor for adverse health outcomes and may disproportionately burden lower socioeconomic status groups, exacerbating health disparities. We explored associations of demographic factors, stressful life events, and chemical co-exposures, with cotinine levels, among girls in the CYGNET Study. Data were collected from families of girls aged 6-8 years old in Northern California, through clinic exams, questionnaires and biospecimens (n = 421). Linear regression and factor analysis were conducted to explore predictors of urinary cotinine and co-exposure body burdens, respectively. In unadjusted models, geometric mean cotinine concentrations were higher among Black (0.59 ug/g creatinine) than non-Hispanic white (0.27), Asian (0.32), or Hispanic (0.34) participants. Following adjustment, living in a rented home, lower primary caregiver education, and lack of two biologic parents in the home were associated with higher cotinine concentrations. Girls who experienced parental separation or unemployment in the family had higher unadjusted cotinine concentrations. Higher cotinine was also associated with higher polybrominated diphenyl ether and metals concentrations. Our findings have environmental justice implications as Black and socio-economically disadvantaged young girls experienced higher ETS exposure, also associated with higher exposure to other chemicals. Efforts to reduce ETS and co-exposures should account for other disparity-related factors