Modeling the Behavior of the Surface to Liquid Interfaces in an Electrolytic Liquid

Understanding the mechanism for charge transfer between electrodes within an electrolyte dissolved in water is vital to better understanding the sources of electrical noise in the system. This research compares the electrical properties of liquid top gated graphene devices with the properties of two metal probes to model the system. By measuring the impedance of these systems at different frequencies, it is possible to develop a model of their electrical properties and to consider techniques to improve signal to noise at graphene interfaces

Finite-frequency wave propagation through outer rise fault zones and seismic measurements of upper mantle hydration

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 43 (2016): 7982–7990, doi:10.1002/2016GL070083.Effects of serpentine-filled fault zones on seismic wave propagation in the upper mantle at the outer rise of subduction zones are evaluated using acoustic wave propagation models. Modeled wave speeds depend on azimuth, with slowest speeds in the fault-normal direction. Propagation is fastest along faults, but, for fault widths on the order of the seismic wavelength, apparent wave speeds in this direction depend on frequency. For the 5–12 Hz Pn arrivals used in tomographic studies, joint-parallel wavefronts are slowed by joints. This delay can account for the slowing seen in tomographic images of the outer rise upper mantle. At the Middle America Trench, confining serpentine to fault zones, as opposed to a uniform distribution, reduces estimates of bulk upper mantle hydration from ~3.5 wt % to as low as 0.33 wt % H2O.NSF Grant Number: OCE-08410632017-02-1

High rates of HIV testing despite low perceived HIV risk among African-American sexually transmitted disease patients.

In the current diagnosis-based, human immunodeficiency virus (HIV) prevention climate, previous testing among persons at elevated HIV risk has cost and efficacy implications, as it signals continued behavioral risk, limited HIV knowledge or overuse of services. This study sought to determine the proportion of African Americans newly seeking sexually transmitted disease (STD) diagnosis who previously had obtained HIV counseling and testing. This was a clinic-based, cross-sectional survey of African-American adults (N=408) seeking STO diagnosis at a public STD clinic located in a high-HIV and STD prevalence city in the U.S. south. Eighty-four percent of respondents had previously obtained HIV counseling and testing: 68% had previously obtained care at the clinic. Sixty-five percent of respondents perceived themselves as having low or no HIV risk. Seventy-two percent correctly answered > or = 3 of 4 HIV knowledge items. Although diagnosis-based HIV prevention initiatives promote HIV counseling and testing for both primary and secondary HIV prevention, these findings suggest that many African-American STD patients remain at risk following testing. Future research should explore how the counseling portion of standard HIV counseling and testing influences subsequent knowledge, attitudes, risk perceptions and behaviors

Biodiversity, Governance, and the Allocation of International Aid for Conservation

There is little systematic knowledge about the magnitude and allocation of international funding flows to support biodiversity conservation in the developing world. Using the newly released AidData compilation, we present a comprehensive assessment of official donor assistance for biodiversity during 1980–2008. We find that biodiversity aid increased markedly in the early 1990s, but that estimates of current aid are likely overstated and donor commitments at the 1992 Rio Earth Summit have not been met. Aid has been well targeted, however, in that the allocation of biodiversity aid is positively associated with the number of threatened species in recipient countries after controlling for country size, national population, and wealth. Biodiversity aid is also positively associated with indicators of good governance. Our results provide an empirical measure of progress toward international conservation funding targets, a baseline against which future flows can be compared, and information necessary to assess the effectiveness of biodiversity aid.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96771/1/j.1755-263X.2012.00270.x.pd

Thermal And Mechanical Response Of Particulate Composite Plates Under Inertial Excitation

The thermal and mechanical, near-resonant responses of particulate composite plates formed from hydroxyl-terminated polybutadiene (HTPB) binder and varying volume ratios of ammonium chloride (NH4Cl) particles (50, 65, 75%) are investigated. Each test specimen is clamped and forced with three levels of band-limited, white noise inertial excitation (10–1000 Hz at 1.00, 1.86 and 2.44 g RMS). The mechanical response of each plate is recorded via scanning laser Doppler vibrometry. The plates are then excited at a single resonant frequency and the thermal response is recorded via infrared thermography. Comparisons are made between the mechanical operational deflection shapes of each plate and spatial temperature distributions, with correlation seen between the observed level of strain, as visualized by strain energy density, and heat generation. The effect of particle/binder ratio on both the thermal and mechanical responses is discussed. Acquired results are also compared to an analytical model of the system. The observed thermomechanical effects render an improved understanding of the thermomechanics of plastic-bonded composites, an essential step in support of the development of new technologies for the vapor-based detection of hidden explosives

Controlling the False Discovery Rate in Astrophysical Data Analysis

The False Discovery Rate (FDR) is a new statistical procedure to control the number of mistakes made when performing multiple hypothesis tests, i.e. when comparing many data against a given model hypothesis. The key advantage of FDR is that it allows one to a priori control the average fraction of false rejections made (when comparing to the null hypothesis) over the total number of rejections performed. We compare FDR to the standard procedure of rejecting all tests that do not match the null hypothesis above some arbitrarily chosen confidence limit, e.g. 2 sigma, or at the 95% confidence level. When using FDR, we find a similar rate of correct detections, but with significantly fewer false detections. Moreover, the FDR procedure is quick and easy to compute and can be trivially adapted to work with correlated data. The purpose of this paper is to introduce the FDR procedure to the astrophysics community. We illustrate the power of FDR through several astronomical examples, including the detection of features against a smooth one-dimensional function, e.g. seeing the ``baryon wiggles'' in a power spectrum of matter fluctuations, and source pixel detection in imaging data. In this era of large datasets and high precision measurements, FDR provides the means to adaptively control a scientifically meaningful quantity -- the number of false discoveries made when conducting multiple hypothesis tests.Comment: 15 pages, 9 figures. Submitted to A

Bioelectronic DNA detection of human papillomaviruses using eSensor™: a model system for detection of multiple pathogens

BACKGROUND: We used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor™) in identifying multiple pathogens. METHODS: Two chips were spotted with capture probes consisting of DNA oligonucleotide sequences specific for HPV types. Electrically conductive signal probes were synthesized to be complementary to a distinct region of the amplified HPV target DNA. A portion of the HPV L1 region that was amplified by using consensus primers served as target DNA. The amplified target was mixed with a cocktail of signal probes and added to a cartridge containing a DNA chip to allow for hybridization with complementary capture probes. RESULTS: Two bioelectric chips were designed and successfully detected 86% of the HPV types contained in clinical samples. CONCLUSIONS: This model system demonstrates the potential of the eSensor platform for rapid and integrated detection of multiple pathogens