Energy Level Alignment at Molecule-Metal Interfaces from an Optimally-Tuned Range-Separated Hybrid Functional

The alignment of the frontier orbital energies of an adsorbed molecule with the substrate Fermi level at metal-organic interfaces is a fundamental observable of significant practical importance in nanoscience and beyond. Typical density functional theory calculations, especially those using local and semi-local functionals, often underestimate level alignment leading to inaccurate electronic structure and charge transport properties. In this work, we develop a new fully self-consistent predictive scheme to accurately compute level alignment at certain classes of complex heterogeneous molecule-metal interfaces based on optimally-tuned range-separated hybrid functionals. Starting from a highly accurate description of the gas-phase electronic structure, our method by construction captures important nonlocal surface polarization effects via tuning of the long-range screened exchange in a range-separated hybrid in a non-empirical and system-specific manner. We implement this functional in a plane-wave code and apply it to several physisorbed and chemisorbed molecule-metal interface systems. Our results are in quantitative agreement with experiments, both the level alignment and work function changes. Our approach constitutes a new practical scheme for accurate and efficient calculations of the electronic structure of molecule-metal interfaces.Comment: 15 pages, 8 figure

Analyzing Postdisaster Surveillance Data: The Effect of the Statistical Method

Data from existing administrative databases and ongoing surveys or surveillance methods may prove indispensable after mass traumas as a way of providing information that may be useful to emergency planners and practitioners. The analytic approach, however, may affect exposure prevalence estimates and measures of association. We compare Bayesian hierarchical modeling methods to standard survey analytic techniques for survey data collected in the aftermath of a terrorist attack. Estimates for the prevalence of exposure to the terrorist attacks of September 11, 2001, varied by the method chosen. Bayesian hierarchical modeling returned the lowest estimate for exposure prevalence with a credible interval spanning nearly 3 times the range of the confidence intervals (CIs) associated with both unadjusted and survey procedures. Bayesian hierarchical modeling also returned a smaller point estimate for measures of association, although in this instance the credible interval was tighter than that obtained through survey procedures. Bayesian approaches allow a consideration of preexisting assumptions about survey data, and may offer potential advantages, particularly in the uncertain environment of postterrorism and disaster settings. Additional comparative analyses of existing data are necessary to guide our ability to use these techniques in future incidents

Recovery Research, Katrina's Fifth Anniversary, and Lessons Relearned

What may be called “disaster science” is a broad field that begins with understanding hazards, risks, and population vulnerabilities and moves on to establishing best-practice models of response, mitigation, and recovery. Gaps abound in our collective knowledge in all of these areas, and it is fair to suggest that we have only begun to scratch the surface in terms of what we need to know. The goal continues to be to learn how to prevent disasters whenever possible and, when prevention is not possible, to at least optimize survival, preserve vital infrastructure, and return rapidly to a state of normalcy

Lessons from Katrina – What Went Wrong, What Was Learned, Who’s Most Vulnerable

If humans did not occupy the planet, disasters would never occur. Massive climatic events, earthquakes, volcanic eruptions, and tsunamis would be regular occurrences, of course, and the earth would look like a dynamic cauldron of natural activity, changing the look and the balance of nature and natural events continuously and randomly. What morphs these natural phenomenon into catastrophic events we call “disasters” is simply the presence of human beings who by choice, chance, or necessity find themselves in harm’s way. The “human factors” may be straightforward and benign. For instance, people making their livelihood from the sea are at risk from coastal storms and tsunamis. Similarly, people are found living in areas at considerable risk for mudslides and volcanoes. It could even be said that living in New Orleans, a coastal city actually below sea level, is a gamble, as was so dramatically emphasized by the storms and subsequent flooding of August and September 2005

Hurricane Sandy: Lessons Learned, Again

Hurricane Sandy was a sobering reminder to those of us who call New York home that it is a port city and subject to the whims of wind and water. The storm itself was massive: climatologically, a thousand miles wide at its peak; economically, an estimated excess of $50 billion in damages. In the New York metropolitan area, 97 people died in the storm, thousands were displaced from their homes, and 2 major hospitals required perilous evacuations even as the hurricane force winds engulfed the metropolitan region. For those of us in the fields of disaster medicine and public health preparedness, the question is, were we ready? During the past decade considerable public investment has been made in standardizing command and communication, assuring appropriate and rapid supply chains, and training the medical and public health workforces to respond appropriately. And yet, in the week after the storm, persistent reports of widespread gaps in the provision of coordinated relief were received from the Rockaways to Coney Island to Staten Island and New Jersey. The question was not one of capacity and capability as much as it was of communication and coordination. Resources did not always make it the last mile to reach those most in need

Planning for Long‐Term Recovery Before Disaster Strikes: Case Studies of 4 US Cities: A Final Project Report

Among the four phases along the hazard continuum -- preparedness, response, recovery, and mitigation -- the sub‐field of long‐term recovery has long been an outlier, an "orphan" when it comes to concerted policy attention and pre‐disaster planning. It's not that community residents or municipal and state government officials are unaware of the potential long‐term residual consequences of natural disasters. Since the attacks of September 11, 2001 and the subsequent creation of the Department of Homeland Security, the U.S. government has spent billions of dollars to upgrade and enhance the country's ability to detect and respond to major catastrophic events, whether man‐made or natural in origin. The country experienced catastrophic wildfires in 2003, 2007‐2008, and 2011, a regional electrical blackout affecting 9 states and part of Canada in 2003, major Midwest flooding in 2008 and again this year, Category 3 or greater hurricanes in 2004, 2005, and 2008, and significant tornado clusters in 2011 that claimed 529 lives and caused over $17 billion in damages. These hazards have struck virtually every region of the country, and the consequences are readily evident to emergency managers and local city and county. Although the ratio of uncovered to covered losses has declined over this three‐decade timeframe, from approximately 8:1 to 4:1, absolute dollar losses have escalated tremendously. This may represent gains in mitigation efforts to insure against losses in high‐risk areas, but the size and growth of uncovered losses suggest a growing recovery challenge. This difference between covered and uncovered losses reflects the absolute minimum investment required for affected areas to return to pre‐event conditions, much less build back to a better or higher standard. Furthermore, what this trend line cannot capture are those disaster consequences not so easily monetized -- diminished physical and mental health among an affected citizenry, loss of a sense of community and attachment to place, or large scale social disruptions or population displacements. Given the magnitude of the social investment needed to pursue long‐term recovery after a disaster, and the attention that other phases in the hazard continuum have experienced, why is recovery still a policy orphan, and what are the local implications for pre‐disaster planning for long‐term recovery

Assessing the Reliability and Validity of the Evacuation Support Decision Tool

This study examines the reliability and validity of the Evacuation Decision Support Tool (EDST). The EDST is designed to provide healthcare facilities, emergency managers, and other agencies with a systematic process with which to evaluate and guide “evacuation” versus “shelter in place” decision making for a variety of “all hazards” situations. The EDST is comprised of 7 items that assess “threat” and 9 items that measure “consequences” of a situation. The tool was designed to provide users with a decision on whether to remain, prepare, or evacuate from a healthcare facility. To date, there has not been a study that examined psychometric properties of any evacuation decision tool, including the EDST