Nonparaxial shape-preserving Airy beams with Bessel signature

Spatially accelerating beams that are solutions to the Maxwell equations may propagate along incomplete circular trajectories, after which diffraction broadening takes over and the beams spread out. Taking these truncated Bessel wave fields to the paraxial limit, some authors sustained that it is recovered the known Airy beams (AiBs). Based on the angular spectrum representation of optical fields, we demonstrated that the paraxial approximation rigorously leads to off-axis focused beams instead of finite-energy AiBs. The latter will arise under the umbrella of a nonparaxial approach following elliptical trajectories in place of parabolas. Deviations from full-wave simulations appear more severely in beam positioning rather than its local profile

Economic and social impacts of logging at national forests - a study case at Brazil

Brazil has the largest tropical rainforests in the world and most of them are located at Amazon River basin area. During the last three decades, deforestation are growing very fast in this region, having negative impacts at local and global weather. In order to minimize these impacts and protect part of the biodiversity, Brazilian government established several national forests in this area, but just one have being explored, the Tapajós National Forest (known as Flona Tapajós). This paper evaluates the economic and social features of a reduced impact logging project conducted at Flona Tapajós from 1999 to 2003. It was coordinated by IBAMA (the Brazilian governmental agency responsible for managing National Forests), funded by ITTO (International Tropical Timber Organization) and conducted by Treviso Agropecuária Ltda (a private enterprise). This project is locally known as ITTO project. Basing on field interviews and examining IBAMA´s and Treviso´s documents, this paper concludes that ITTO project was highly profitable for the private company, in spite of the company had obeyed all Brazilian working laws, what is not very common at this Brazilian region. Treviso´s internal rate of return was 35.79%. ITTO project impacted significantly the community workers involved with the project and it was able to teach this population how to manage rainforests in order to produce timber without destroying them. The paper ends by suggesting some attitudes that Brazilian government can follow in its discussion about new reduced impact logging projects to be implemented at Flona Tapajós and other national forests by both private enterprises and local communities.

Light capsules shaped by curvilinear meta-surfaces

We propose a simple yet efficient method for generating in-plane hollow beams with a nearly-full circular light shell without the contribution of backward propagating waves. The method relies on modulating the phase in the near field of a centro-symmetric optical wavefront, such as that from a high-numericalaperture focused wave field. We illustrate how beam acceleration may be carried out by using an ultranarrow non-flat meta-surface formed by engineered plasmonic nanoslits. A mirrorsymmetric, with respect to the optical axis, circular caustic surface is numerically demonstrated that can be used as an optical bottle

Hypertension and Hypertension-Related Disparities in Underrepresented Minorities

Racial-ethnic disparities in cardiovascular disease (CVD) have been evident over the past few decades. As such, addressing these disparities have been a part of national programs such as Health People 2020 and the Million Heart initiative. Hypertension (HTN) has been a primary focus of these initiatives due to the significant contribution of HTN as a risk factor for CVD and its role in CVD racial/ethnic disparities. HTN is common among various racial/ethnic groups, in particular non-Hispanic blacks and certain groups of Hispanics. Additionally, both non-Hispanic black and Hispanic adults have been known to have higher prevalence of poorly controlled blood pressure (BP) compared to non-Hispanic whites. Long-standing HTN leads to increased risk of end-organ damage, development of coronary heart disease, stroke, end-stage kidney disease, and increased overall CVD-specific mortality. This chapter provides an update of available data on the prevalence of HTN in various racial/ethnic groups and prevalence of awareness, treatment, and control of HTN in attempts to further demonstrate the significant role HTN plays in racial/ethnic disparities in CVD. We also discuss the most recently published HTN guidelines that has led to debate regarding the potential impact on worsening CVD disparities, through disproportionate effects on the elderly, women, and non-Hispanic blacks