Gravity drainage in porous media: the effect of wetting

In order to relate the wetting properties at the pore scale to the macroscale hydrodynamics, a series of benchmark experiments on the effect of the wetting on flow in porous media were performed. Gravity drainage of hexane (oil) in a model porous medium consisting of water-wet sand was studied using γ-ray densitometry and weight measurements. The advantage of our system is that we know and control the wetting properties perfectly: we can tune the wetting properties by changing the salinity of the water. This allows us to perform porous medium flow experiments for the different wetting states without changing the transport properties (viscosity and density) of the oil. Drainage is found to be more efficient and, consequently, oil recovery more important for partial wetting.     

Global patterns of linkage disequilibrium at the CD4 locus and modern human origins

Haplotypes consisting of alleles at a short tandem repeat polymorphism (STRP) and an Alu deletion polymorphism at the CD4 locus on chromosome 12 were analyzed in more than 1600 individuals sampled from 42 geographically dispersed populations (13 African, 2 Middle Eastern, 7 European, 9 Asian, 3 Pacific, and 8 Amerindian). Sub-Saharan African populations had more haplotypes and exhibited more variability in frequencies of haplotypes than the Northeast African or non-African populations. The Alu deletion was nearly always associated with a single STRP allele in non-African and Northeast African populations but was associated with a wide range of STRP alleles in the sub-Saharan African populations. This global pattern of haplotype variation and linkage disequilibrium suggests a common and recent African origin for all non-African human populations.     

Sulfur‐Enriched Conjugated Polymer Nanosheet Derived Sulfur and Nitrogen co‐Doped Porous Carbon Nanosheets as Electrocatalysts for Oxygen Reduction Reaction and Zinc–Air Battery

Among the rising 2D soft materials, conjugated polymer nanosheets are one of the most promising and new classes of polymeric materials, which are rarely developed because of the challenge in controlling the dimensionality and lack of synthetic strategies. In this study, one kind of sulfur‐enriched conjugated polymer nanosheet (2DP‐S) with a high aspect ratio of up to ≈400 is successfully synthesized. On the basis of structural characterization, as‐prepared 2DP‐S possesses the chemical identity of cruciform‐fused polymeric backbone consisting of quinoidal polythiophene and poly(p‐phenylenevinylene) along horizontal and vertical directions, respectively, by sharing two alternating single–double carbon–carbon bonds in each repeat unit. The unique structural conformation of 2DP‐S renders carrier mobilities of up to 0.1 ± 0.05 cm² V^?1 s^?1, a figure inferred from Terahertz time domain spectroscopy. Moreover, upon thermal treatment, 2DP‐S is readily converted into N/S dual‐doped porous carbon nanosheets (2DPCs) under ammonia atmosphere, whose N/S ratio can be rationally controlled by adjusting the activation time. The catalytic performance of the oxygen reduction reaction of as‐prepared 2DPCs is well tunable by the rationally controlled N/S contents. These results offer a new pathway for exploring heteroatom‐doped porous carbons applicable for energy conversion and storage.     

Review of Health consequences of abuse in the family: A clinical guide for evidence-based practice.

Reviews the book, Health consequences of abuse in the family: A clinical guide for evidence-based practice, edited by Kathleen A. Kendall-Tackett (see record 2003-88342-000). This book is a comprehensive clinical guide that stresses the necessity of assessing and understanding the effects of abuse on physical health. Each chapter succinctly captures unique issues relevant to the assessment and treatment of abuse with at-risk populations (e.g., children with disabilities, battered women, those with traumatic brain injuries, elderly individuals, and minority women). The book gives thoughtful consideration to the barriers in assessing abuse and provides insightful suggestions on how to overcome those obstacles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Linkage of congenital, recessive deafness (DFNB4) to chromosome 7q31 and evidence for genetic heterogeneity in the Middle Eastern Druze population

Clinically significant hearing loss affects 1 in 1000 infants and it is estimated that at least 50% of these cases are due to a genetic cause. Some forms of inherited deafness are syndromic and affected individuals have a specific pattern of additional features while in other families the deafness is non-syndromic and there is no other recognizable phenotype. Analysis of several large families with syndromic and non-syndromic forms of deafness have been used in genetic linkage analysis to identify genes or gene locations that cause deafness. Here, we describe a large Middle-Eastern Druze family with recessive non-syndromic deafness and demonstrate linkage between deafness in this family and human chromosome 7q31 with a lod score exceeding 5.5. This is the first evidence for a gene at this location that causes deafness. In addition, we found that deafness in three other Druze pedigrees, one related to the linked family, is not linked to this chromosomal location. This suggests that there are multiple nonallelic mutations for deafness in this genetic isolate.     

Editorial

Mobile Networks and Applications -     

Estimation of the moisture content of bare soil from RADARSAT-1 SAR using simple empirical models

Synthetic Aperture Radar (SAR) provides a remote sensing tool to estimate soil moisture. Mapping surface soil moisture from the grey level of SAR images is a demonstrated procedure, but several factors can interfere with the interpretation and must be taken into account. The most important factors are surface roughness and the radar configuration (frequency, polarization and incidence angle). This Letter evaluates the influence of these variables for estimation of bare soil moisture using RADARSAT-1 SAR data. First, the parameters of two linear backscatter models, the Ji and Champion models (Ji et al . 1995, Champion 1996), were tested and the constants recalculated. rms error based on the backscattering coefficient was reduced from 6.12 and 6.48 dB to 4.28 and 1.68 dB for the Ji and Champion models respectively. Secondly, a new model is proposed which had an rms error of only 1.21 dB. The results showed a marked increase in accuracy compared with the previous models.     

A case study in library‐based scholarly publishing: The university of Michigan library's scholarly publishing office

In recent years, institutions of higher learning and research and the libraries that support them have become increasingly concerned about the costs and conditions of the publication and distribution of scholarship. In response, several universities have begin to explore the possibility of their libraries functioning as publishers, particularly looking to explore the possibilities and costs of electronic publication. The University of Michigan Library's Scholarly Publishing Office(l) (SPO) is one such institutional venue for the electronic publication and distribution of scholarly content. This discussion summarizes some of the policy issues that led to the creation of SPO, and describes SPO's organisation and some of the activities that instantiate its mission of building sustainable publication models that bridge the gap between academic self‐publishing and large, aggregated, commercial publishing. It also raises several questions about how libraries should function as publishers, and about cooperation and collaboration in building alternative venues for scholarly publishing. In detailing the work of SPO, the author hopes to use it as a case study to illuminate the mission of library‐based scholarly publishing efforts and the challenges such efforts must meet in order to succeed.     

Quantifying Polaron Formation and Charge Carrier Cooling in Lead‐Iodide Perovskites

Notwithstanding the success of lead‐halide perovskites in emerging solar energy conversion technologies, many of the fundamental photophysical phenomena in this material remain debated. Here, the initial steps following photogeneration of free charge carriers in lead‐iodide perovskites are studied, and timescales of charge carrier cooling and polaron formation, as a function of temperature and charge carrier excess energy, are quantified. It is found, using terahertz time‐domain spectroscopy (THz‐TDS), that the observed femtosecond rise in the photoconductivity can be described very well using a simple model of sequential charge carrier cooling and polaron formation. For excitation above the bandgap, the carrier cooling time depends on the charge carrier excess energy and lattice temperature, with cooling rates varying between 1 and 6 meV fs^?1, depending on the cation. While carrier cooling depends on the cation, polaron formation occurs within ≈400 fs in CH₃NH₃PbI₃ (MAPbI₃), CH(NH₂)₂PbI₃ (FAPbI₃), and CsPbI₃. Its formation time is independent of temperature between 160 and 295 K. The very similar polaron formation dynamics observed for the three perovskites points to the critical role of the inorganic lattice, rather than the cations, for polaron formation.     

Contactless conductivity detection for capillary electrophoresis

A contactless capacitively coupled conductivity detector for capillary electrophoresis is introduced. The detector consists of two electrodes which are placed cylindrically around the outer polyimide coating of the fused-silica capillary with a detection gap of 2 mm. The electrodes form a cylindrical capacitor, and the electric conductivity of the solution in the gap between the electrodes is measured. A high audio or low ultrasonic frequency for coupling of the ac voltage is used in order to minimize the influence of reactance of the liquid. For an improved version of the detector, two syringe cannulas are used as the electrodes and the capillary is simply assembled into the tubing. This allows an easy placement of the detector on various positions along the capillary. The limit of detection of inorganic cations and anions is 200 ppb, as determined for sodium and chloride, respectively.