The molecular structure of the interface between water and a hydrophobic substrate is liquid-vapor like

With molecular simulation for water and a tunable hydrophobic substrate, we apply the instantaneous interface construction [A. P. Willard and D. Chandler, J. Phys. Chem. B, 114, 1954 (2010)] to examine the similarity between a water-vapor interface and a water-hydrophobic surface interface. The intrinsic interface refers to molecular structure in terms of distances from the instantaneous interface. We show that attractive interactions between a hydrophobic surface and water affect capillary wave fluctuations of the instantaneous liquid interface, but these attractive interactions have essentially no effect on the intrinsic interface. Further, the intrinsic interface of liquid water and a hydrophobic substrate differs little from that of water and its vapor.The same is not true, we show, for an interface between water and a hydrophilic substrate. In that case, strong directional substrate-water interactions disrupt the liquid-vapor-like interfacial hydrogen bonding network.Comment: 6 pages, 5 figure

The Quest for Electronic Resource Management Standards and Tools

Chapter 6 of 8.Libraries and vendors face significant challenges in the new digital publishing environment. One of these challenges is to manage the information and workflows necessary to acquire and provide access to electronic resources. The growth of electronic journals and databases has both complicated and transformed the acquisition and servicing of library materials. New information and workflows are required to evaluate, select, acquire, license, catalog, and manage electronic products throughout their life-cycle. Current library systems and standards have not kept pace with these changes. In the absence of existing software solutions, many libraries have begun to design and build local automated tools to address this gap. Surveys of locally developed electronic resource management systems reveal a high concentration of shared goals, issues and functional specifications, indicating that the time may be right for a collaborative approach and the establishment of best practices and standards. This chapter will describe the progress that is being made on this front by participants in the Digital Library Federation (DLF) Electronic Resource Management Initiative (http://www.diglib.org/standards/dlf-erm02.htm).Cornell University Librar

The 1992 American Library Association Resolution on Israeli Censorship and Other Human Rights Violations: a Select Bibliography, Placed in the Context of the Existing Literature on the Relationship Between Zionism and U.S. Policy Toward Israel

This thesis is an attempt to systematically capture a large body of ephemeral data produced in the course of a controversy within the American Library Association regarding censorship and other human rights violations in the Israeli Occupied Territories. The focus of the study is the resolution passed by the ALA Council at its annual conference in 1992, then revoked at the next annual conference. The questions guiding this study are: What happened during the controversy? Why? The major result of this study is a select bibliography, arranged chronologically, beginning in 1945, consisting of over 1200 entries: letters, memos, broadsides, minutes to meetings, resolutions, policies; and published items from newsletters, magazines, journals, and books. It builds the foundation for an analysis of the most divisive issue in recent ALA history, placing the story into a broader historical framework. The study includes a brief narrative; descriptions of the data sources; discussion of three possible literatures into which the data may fit; and a guide to the bibliography. The data gathered are mixed with the existing literature on Zionism

Building a Virtual City for the Classroom: Angkor

Histor

Deceptive Self-Attack for Cyber-Defense

The asymmetry between cyber-defense and cyber-offense is well-known; defenders must perfectly protect their systems, while attackers need only find one flaw. Defensive cyber-deception has been proposed as a way to mitigate this problem, by using various techniques designed to require attackers to defend themselves from misdirection, false data, and counter-attack. In this paper, we propose a new cyber-deception technique: deceptive self-attack (DSA). DSA modifies network and systems to give the appearance that an unknown third party is also at work attacking the same systems. It is our contention that the presence of this (deceptive) adversary pressures real adversaries in novel ways useful to cyber-defense; and discuss these effects. As a study in DSA, we present and evaluate SoundTheAlarm, a SMT-solver based system for generating deceptive self-attack network traffic. SoundTheAlarm uses public attack signatures from the Suricata intrusion detection system to automatically generate network traffic consistent with a particular cyber-attack signature

Characterizing heterogeneous dynamics at hydrated electrode surfaces

In models of Pt 111 and Pt 100 surfaces in water, motions of molecules in the first hydration layer are spatially and temporally correlated. To interpret these collective motions, we apply quantitative measures of dynamic heterogeneity that are standard tools for considering glassy systems. Specifically, we carry out an analysis in terms of mobility fields and distributions of persistence times and exchange times. In so doing, we show that dynamics in these systems is facilitated by transient disorder in frustrated two-dimensional hydrogen bonding networks. The frustration is the result of unfavorable geometry imposed by strong metal-water bonding. The geometry depends upon the structure of the underlying metal surface. Dynamic heterogeneity of water on the Pt 111 surface is therefore qualitatively different than that for water on the Pt 100 surface. In both cases, statistics of this adlayer dynamic heterogeneity responds asymmetrically to applied voltage.Comment: 6 page, 4 figure

Water exchange at a hydrated platinum electrode is rare and collective

We use molecular dynamics simulations to study the exchange kinetics of water molecules at a model metal electrode surface -- exchange between water molecules in the bulk liquid and water molecules bound to the metal. This process is a rare event, with a mean residence time of a bound water of about 40 ns for the model we consider. With analysis borrowed from the techniques of rare-event sampling, we show how this exchange or desorption is controlled by (1) reorganization of the hydrogen bond network within the adlayer of bound water molecules, and by (2) interfacial density fluctuations of the bulk liquid adjacent to the adlayer. We define collective coordinates that describe the desorption mechanism. Spatial and temporal correlations associated with a single event extend over nanometers and tens of picoseconds.Comment: 10 pages, 9 figure