Band gap engineering in finite elongated graphene nanoribbon heterojunctions: Tight-binding model

A simple model based on the divide and conquer rule and tight-binding (TB) approximation is employed for studying the role of finite size effect on the electronic properties of elongated graphene nanoribbon (GNR) heterojunctions. In our model, the GNR heterojunction is divided into three parts: a left (L) part, middle (M) part, and right (R) part. The left part is a GNR of width $W_{L}$, the middle part is a GNR of width $W_{M}$, and the right part is a GNR of width $W_{R}$. We assume that the left and right parts of the GNR heterojunction interact with the middle part only. Under this approximation, the Hamiltonian of the system can be expressed as a block tridiagonal matrix. The matrix elements of the tridiagonal matrix are computed using real space nearest neighbor orthogonal TB approximation. The electronic structure of the GNR heterojunction is analyzed by computing the density of states. We demonstrate that for heterojunctions for which $W_{L} = W_{R}$, the band gap of the system can be tuned continuously by varying the length of the middle part, thus providing a new approach to band gap engineering in GNRs. Our TB results were compared with calculations employing divide and conquer rule in combination with density functional theory (DFT) and were found to agree nicely.Comment: arXiv admin note: text overlap with arXiv:1404.249

Ecology or Catastrophe: The Life of Murray Bookchin by Janet Biehl

Review of Janet Biehl\u27s Ecology or Catastrophe: The Life of Murray Bookchin

Our Ice Is Vanishing / Sikuvut Nunguliqtuq: A History of Inuit, Newcomers, and Climate Change by Shelley Wright

Review of Shelley Wright\u27s Our Ice Is Vanishing / Sikuvut Nunguliqtuq: A History of Inuit, Newcomers, and Climate Change

Pandemic Influenza: Ethics, Law, and the Public\u27s Health

Highly pathogenic Influenza (HPAI) has captured the close attention of policy makers who regard pandemic influenza as a national security threat. Although the prevalence is currently very low, recent evidence that the 1918 pandemic was caused by an avian influenza virus lends credence to the theory that current outbreaks could have pandemic potential. If the threat becomes a reality, massive loss of life and economic disruption would ensue. Therapeutic countermeasures (e.g., vaccines and antiviral medications) and public health interventions (e.g., infection control, social separation, and quarantine) form the two principal strategies for prevention and response, both of which present formidable legal and ethical challenges that have yet to receive sufficient attention. In part II, we examine the major medical countermeasures being being considered as an intervention for an influenza pandemic. In this section, we will evaluate the known effectiveness of these interventions and analyze the ethical claims relating to distributive justice in the allocation of scarce resources. In part III, we will discuss public health interventions, exploring the hard tradeoffs between population health on the one hand and personal (e.g., autonomy, privacy, and liberty) and economic (e.g., trade, tourism, and business) interests on the other. This section will focus on the ethical and human rights issues inherent in population-based interventions. Pandemics can be deeply socially divisive, and the political response to these issues not only impacts public health preparedness, but also reflects profoundly on the kind of society we aspire to be

Human Rights for Health across the United Nations

The United Nations (UN) plays a central role in realizing human rights to advance global health. Looking beyond state obligations, the UN has called on all its specialized agencies to mainstream human rights across all their activities. With globalization compelling these UN institutions to meet an expanding set of global challenges to underlying determinants of health, human rights are guiding these international organizations in addressing public health. These international organizations within the UN system are actively engaged in implementing health-related human rights—in both their mission and their actions to carry out that mission. Through this mainstreaming of human rights, global health institutions have embraced human rights treaty obligations as a framework for global governance. Given the dramatic development of human rights law through the UN and the parallel proliferation of UN institutions devoted to global health and development, there arises an imperative to understand the implementation of human rights in global health governance. This special section analyzes the evolving UN focus on health and human rights in global governance, examining an expansive set of UN institutions that employ human rights in responding to public health challenges in a rapidly globalizing world. To understand the ways in which human rights are implemented, this special section examines the role of institutions across the UN system in the realization of human rights for public health. Drawing from our recent Oxford University Press volume on Human Rights in Global Health: Rights-Based Governance for a Globalizing World, this special section brings together several of the contributors to analyze ongoing efforts to reform UN institutions to mainstream human rights. These contributors—from academia, nongovernmental organizations, and the UN system—explore (1) the foundations of human rights as a framework for global governance, (2) the work of UN organizations across a range of health-related human rights, (3) the influence of rights-based economic governance on public health, and (4) the advancement of health through UN human rights institutions. Looking beyond the chapters in Human Rights in Global Health, this special section examines how international institutions are changing to meet the Sustainable Development Goals (SDGs), with sweeping implications for the mainstreaming of human rights for health across the UN

The distribution of maxima of approximately Gaussian random fields

Motivated by the problem of testing for the existence of a signal of known parametric structure and unknown ``location'' (as explained below) against a noisy background, we obtain for the maximum of a centered, smooth random field an approximation for the tail of the distribution. For the motivating class of problems this gives approximately the significance level of the maximum score test. The method is based on an application of a likelihood-ratio-identity followed by approximations of local fields. Numerical examples illustrate the accuracy of the approximations.Comment: Published in at http://dx.doi.org/10.1214/07-AOS511 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org