The effect of non-uniform microscale distribution of sorption sites on solute diffusion in soil

Conventional models of solute transport in soil consider only soil volumes large enough to average over microscale heterogeneities, and it is assumed that microscale variations are unimportant at the macroscale. In this research we test this assumption for cases in which the microscale distribution of solute-sorbing sites is patchy. We obtain a set of equations at the macroscale that allow for the effect of the microscale distribution with the mathematical technique of homogenization. We combine these equations with an image-based model that describes the true microscale pore geometry in a real, structured soil measured with X-ray computed tomography. The resulting models are used to test the microscale averaging assumptions inherent in conventional models. We show that, in general, macroscale diffusion is little affected by microscale variation in the distribution of sorption sites. Therefore, for most purposes the assumption of microscale averaging used in conventional models is justified. The effects of microscale heterogeneity are noticeable only when (i) the rate of sorption is slow compared with diffusion, but still fast enough to affect macroscale transport and (ii) the defined macroscale volume approaches the microscale. We discuss the effects when these conditions are me

Fluorescence correlation spectroscopy in thin films at reflecting substrates as a means to study nanoscale structure and dynamics at soft-matter interfaces

Structure and dynamics at soft-matter interfaces play an important role in nature and technical applications. Optical single-molecule investigations are non-invasive and capable to reveal heterogeneities at the nanoscale. In this work we develop an autocorrelation function (ACF) approach to retrieve tracer diffusion parameters obtained from fluorescence correlation spectroscopy (FCS) experiments in thin liquid films at reflecting substrates. This approach then is used to investigate structure and dynamics in 100 nm thick 8CB liquid crystal films on silicon wafers with five different oxide thicknesses. We find a different extension of the structural reorientation of 8CB at the solid-liquid interface for thin and for thick oxide. For the thin oxides, the perylenediimide tracer diffusion dynamics in general agrees with the hydrodynamic modeling using no-slip boundary conditions with only a small deviation close to the substrate, while a considerably stronger decrease of the interfacial tracer diffusion is found for the thick oxides.Comment: 8 figure

Mentoring to reduce antisocial behaviour in childhood

The effects of social interventions need to be examined in real life situations as well as studie

Holographic mensuration of suspended particles in aquatic systems

The distribution and dynamics of aggregates in the aquatic environment play an important role in the modelling of biogeochemical processes. Previous work on aggregates in the ocean (e.g. sedimentary 'marine snow' particles), which vary in size from tens of microns to several millimetres, has used electronic counting or conventional photography coupled with image analysis. Here we describe a non-destructive in situ approach by use of holographic mensuration, hologrammetry, that affords greater scope and higher accuracy for the enumeration, sizing, and spatial distribution determination of aggregate particles. By means of two complimentary techniques, in-line and offaxis transmission holography, we present the initial experiments conducted in our laboratory and discuss the preliminaiy results from real image analysis

Evaluation of ASTER GDEM ver2 using GPS measurements and SRTM ver4.1 in China

The freely available ASTER GDEM ver2 was released by NASA and METI on October 17, 2011. As one of the most complete high resolution digital topographic data sets of the world to date, the ASTER GDEM covers land surfaces between 83°N and 83°S at a spatial resolution of 1 arc-second and will be a useful product for many applications, such as relief analysis, hydrological studies and radar interferometry. The stated improvements in the second version of ASTER GDEM benefit from finer horizontal resolution, offset adjustment and water body detection in addition to new observed ASTER scenes. This study investigates the absolute vertical accuracy of the ASTER GDEM ver2 at five study sites in China using ground control points (GCPs) from high accuracy GPS benchmarks, and also using a DEM-to-DEM comparison with the Consultative Group for International Agriculture Research Consortium for Spatial Information (CGIAR-CSI) SRTM DEM (Version 4.1). And then, the results are separated into GlobCover land cover classes to derive the spatial pattern of error. It is demonstrated that the RMSE (19m) and mean (-13m) values of ASTER GDEM ver2 against GPS-GCPs in the five study areas is lower than its first version ASTER GDEM ver1 (26m and -21m) as a result of the adjustment of the elevation offsets in the new version. It should be noted that the five study areas in this study are representative in terms of terrain types and land covers in China, and even for most of mid-latitude zones. It is believed that the ASTER GDEM offers a major alternative in accessibility to high quality elevation data

Complex study of H-induced structural rearrangements in FeZr glasses

Microstructural changes and relaxation processes were examined in Fe-Zr based rapidly solidified samples. These phenomena occur far below crystallization temperature in the course of heat treatment, or even at room temperature, induced by absorbed hydrogen

Understanding the Support Needs of Minority Women with Heart Disease

Background. Cardiovascular disease (CVD) affects minority women disproportionately. WomenHeart: The National Coalition for Women with Heart Disease sought to determine effective ways to support non-Caucasian women with CVD. We surveyed women of color living with CVD to understand their unique CVD-related support needs. Methods. 514 non-white women (100 Hispanic, 180 African American, 104 Asian, 107 Indigenous, 23 multiracial) with CVD from 46 states responded to a 55-question survey (online/telephone, English/Spanish) 8/28/15 through 9/11/15. Results. Among respondents not currently attending support groups, 80% were interested in attending support groups. Of WomenHeart services, respondents were most interested in online message boards. Among new services, respondents were most interested in a support group with a medical expert facilitator. Women with tachycardia wanted a support group with others with the same condition. Those with cardiomyopathy preferred to meet most frequently. Respondents most preferred a monthly support group with flexible membership. Community venues were the most popular location for support groups. Indigenous populations had the lowest CVD knowledge and self-efficacy levels, were most likely to prefer a support group with women of their own race, and wished to meet with their groups most frequently. Multiracial women were most likely to have never been told about clinical trials and were least interested in support groups. Hispanics had the least social support. Conclusions. Minority women with CVD indicated interest in support groups. They may benefit from referrals to tailored support group types, including online platforms facilitated by medical experts, and to cardiac rehabilitation and clinical trials

Technology News, July-August 2006

Technology News is a newsletter produced by the Iowa Department of Transportation to provide information to the transportation specialist in Iowa's cities and counties. Technology News is one of CTRE's primary avenues for exchanging transportation-related information with local agencies. The bimonthly newsletter gives an up-to-date look to the up-to-date information our 2,500+ readers have grown to expect

Prevalence of deliberate self harm and attempted suicide within contemporary Goth youth subculture: longitudinal cohort study

<b>Objective</b> To investigate whether deliberate self harm is associated with contemporary Goth youth subculture. <b>Design</b> Longitudinal cohort study. <b>Setting</b> School and community based study of young people living in the Central Clydeside Conurbation, Scotland. <b>Participants</b> 1258 people aged 19, surveyed in 2002-4 and followed-up since age 11 (1994). <b>Main outcome measures</b> Lifetime prevalence of self harm and attempted suicide and their association with Goth youth subculture, before and after adjusting for confounders. <b>Results</b> Identification as belonging to the Goth subculture was strongly associated with lifetime self harm and attempted suicide, with a prevalence of 53% and 47%, respectively among the most highly identified group, and evidence for a dose-response relation. Adjusting for potential confounders did not significantly attenuate this association. Analysis of other youth subcultures showed that this effect was primarily associated with Goth subculture. <b>Conclusions</b> Identification as belonging to the Goth subculture was the best predictor of self harm and attempted suicide. Although based on small numbers, additional longitudinal analysis suggests both selection and modelling mechanisms are involved, selection mechanisms possibly being more likely