Direct measurement of salt–mineral repulsion using atomic force microscopy

The disjoining pressure between a mineral and soluble salt crystal in concentrated aqueous solution has been successfully measured with atomic force microscopy

What The Health Are You Talking About?

This handout conveys bullet points regarding how a teenager can make healthy eating and lifestyle choices. It provides further resources for the client to access.https://dune.une.edu/an_studedres/1063/thumbnail.jp

Fermion masses and symmetry breaking of a U(2) flavour symmetry

We show how a specific sequential breaking pattern of a U(2) flavour symmetry occurs automatically in a broad framework. The relative orientation in U(2) space of the spurion fields that breaks the U(2) symmetry is uniquely fixed, thus determining the form of the fermion mass matrices in a predictive way.Comment: 9 pages, uses amsmath.st

Something Like a Phenomenon: High Achieving Women of Color and Experiences of Mental Health Resource Utilization

The purpose of this study was to examine, explore, and understand the lived experiences of high-achieving Black and Latina women who had utilized mental health services in the last 18 months. The impact of discrimination and stigma is present today and may manifest itself within communities of color when these individuals attempt to access mental health services. The counseling field and counselor education programs are ethically responsible for integrating social justice counseling into coursework and practice. This informs educators and counselors of barriers that may influence and impact best practices for providing mental health services to communities of color. A qualitative design using the transcendental phenomenological approach was used to describe the meaning and experiences ascribed to utilizing mental health care and any perceived stigma. Nine participants were recruited to participated in individual semi-structured interviews consisting of 12-16 questions. Participants were African American women (AAW) with a minimum of two college degrees and a minimum of at least 2 years working in their chosen fields. Data were analyzed using methods outlined by Moustakas’ (1994) data analysis procedures

Discussion of "Predicting water permeability in sedimentary rocks from capillary imbibition and pore structure" by D. Benavente et al., Engineering Geology (2015) [doi: 10.1016/j.enggeo.2015.06.003]

The relation between permeability and sorptivity has not received much attention in the literature of porous materials. Therefore the paper of Benavente et al. (Benavente et al., 2015) is a valuable contribution, both for its theoretical analysis and for providing new data on these properties in a test set of rocks, mostly carbonates. In this Discussion we make some related observations on the topic. We employ the quantities and notation of (Benavente et al., 2015), except that we use the sorptivity S rather than the water absorption coefficient C by capillarity” in describing imbibition. The two are simply related since S = C/ρw where ρw is the density of water

Tweeting the headlines: the impact of social media endorsement on young adult news readers

Title from PDF of title page (University of Missouri--Columbia, viewed on September 9, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. Esther ThorsonIncludes bibliographical references.M.A. University of Missouri--Columbia 2013.Dissertations, Academic -- University of Missouri--Columbia -- Journalism."May 2013"Since the Internet became a mainstream form of communications in 1999, journalism has become a multi-platform discipline. Twitter is a social media site that is emerging as an avenue for getting news online. Previous research about Twitter, a social networking site that limits messages to 140 characters, has also shown Twitter's promise as a channel for news because of the speed at which information can travel and its ability to connect people. By Twitter users following people and companies, the senders have become endorsers of information. This study looked at how Twitter endorsement effects young adult news readers' perceptions of credibility, bias, interest, arousal, importance and knowledge. The 172 participants were placed into one of three conditions. The conditions were stories endorsed by a professional news media outlet tweets, stories endorsed by a peer tweets and stories not endorsed by social media at all. The study found that participants found stories endorsed by Twitter tweets more credible than the non-endorsed stories. Different media platforms also effected knowledge acquisition. Unlike previous research, which found that newer platforms decreased retention rates, this study found that knowledge acquisition was higher among participants in the professional news outlet social media endorsed news condition. However, participants' social media reading frequency did not correlate with their interest in news. Participants rated print and online news more interesting and read them more frequently

Interactions between environmental stressors: the influence of salinity on host-parasite interactions between Daphnia magna and Pasteuria ramosa

Interactions between environmental stressors play an important role in shaping the health of an organism. This is particularly true in terms of the prevalence and severity of infectious disease, as stressors in combination will not always act to simply decrease the immune function of a host, but may instead interact to compound or even oppose the influence of parasitism on the health of an organism. Here, we explore the impact of environmental stress on host-parasite interactions using the water flea Daphnia magna and it is obligate parasite Pasteuria ramosa. Utilising an ecologically relevant stressor, we focus on the combined effect of salinity and P. ramosa on the fecundity and survival of the host, as well as on patterns of infectivity and the proliferation of the parasite. We show that in the absence of the parasite, host fecundity and survival was highest in the low salinity treatments. Once a parasite was introduced into the environment, however, salinity and parasitism acted antagonistically to influence both host survival and fecundity, and these patterns of disease were unrelated to infection rates or parasite spore loads. By summarising the form of interactions found in the broader Daphnia literature, we highlight how the combined effect of stress and parasitism will vary with the type of stressor, the trait used to describe the health of Daphnia and the host-parasite combination under observation. Our results highlight how the context-dependent nature of interactions between stress and parasitism inevitably complicates the link between environmental factors and the prevalence and severity of diseas

Discussion of “Learning from Failure of a Long Curved Veneer Wall: Structural Analysis and Repair” by Paulo B. Lourenço and Pedro Medeiros

The authors, in an interesting and valuable paper, describe the failure of the brick-masonry veneer façade of a multiuse public hall in Gondomar, Portugal. Damage occurred within 2 years of construction. The veneer was a single leaf of continuous brick masonry tied to a RC structural wall, forming a cavity of nominal width 0.07 m that was partly filled with foamed polyurethane. The veneer wall was 242 m in length and 15 m in height, without movement joints, and extended around most of the elliptical perimeter of the building with portions facing north, east, and south. From their site investigations and technical analysis, the authors attributed the failure primarily to effects of “the irreversible expansion of clay brick,” apparent both from cracking and from extensive out-of-plane deformation of the wall, which had widened the cavity to as much as 0.13 m. Effects were greater on parts of the wall facing south. The failure analysis made use of a power law proposed by Wilson et al. (2003) to describe how expansive strain develops in fired-clay ceramics with time. Here, the discussers comment on recent fundamental work on moisture expansion in brick, and in particular on its temperature dependence, matters of direct relevance to the paper under discussion. The discussers’ comments support and extend the conclusions of the authors, with which the discussers broadly agree. Irreversible moisture expansion occurs as a result of slow chemical reactions between components of the fired-clay ceramic and environmental moisture (Hamilton and Hall 2012). The magnitude of the expansion varies strongly with brick mineralogy and kiln firing history, but a predictive model for expansion based on these factors does not yet exist. However, in general, highly crystalline engineering ceramics produced at high kiln temperatures expand less than low-fired ceramics with a higher amorphous content. The penalty is that high-fired ceramics tend to be more brittle and prone to cracking. It is now established that the expansive reaction continues indefinitely, although at a diminishing rate over all timescales; therefore, there is no well-defined time at which it ceases. Recent reanalysis of published data (Hall et al. 2011; Hall and Hoff 2012) shows that the equation e=at1/4 accurately describes expansion strain e over periods of time t as long as 65 years. It follows from this equation that expansive strain at 16 years is double the value at 1 year and three times the 1-year value at 81 years. The persistence of the expansion reaction, albeit at a diminishing rate, emphasizes the need to incorporate appropriate movement joints in masonry design. The authors mention the possibility of using a “poor mortar” to accommodate some of the expansive strain. The use of weak mortars undoubtedly explains the absence of expansion damage in some much-older buildings with thick brick walls. However, the discussers consider that in thin brick veneers, such as those used in Gondomar, a weak mortar is potentially dangerous. It is unfortunate both for design and for failure analysis that the test procedures generally used to characterize clay brick do not provide values of the expansivity a that are needed to apply the equation e=at1/4 . Accelerated steam tests, such as EN772-19 cited by the authors, are at best semiquantitative. In our view, it is essential to determine the expansivity from measurements of expansion strain made over an appropriate period of time under controlled conditions (Hall and Hoff 2012). The discussers also draw attention to the important practical matter of the temperature dependence of the moisture expansivity (Hall et al. 2013). The fact that moisture expansion is the direct consequence of a chemical rehydroxylation reaction (Hamilton and Hall 2012) ensures that the expansivity increases notably with temperature. Available data indicate that the activation energy (which controls the temperature dependence) is about 70 kJ/mol. This means, for example, that the expansivity a of any brick material is about 60% greater at a temperature of 30°C than it is at 10°C. Thus, if a limit expansion strain (say, 1×10−3) is reached in a particular material in 50 years at 10°C, the same strain is attained in the same material in only 7 years at 30°C. It seems likely that its strong temperature dependence explains why moisture expansion is perceived differently in different geographical regions [e.g., McNeilly (1985)] and generally receives more attention in regions with warmer climates, such as Australia, southern Asia, and Brazil. However, in any particular region, the magnitude of expansion and the associated damage within individual buildings are influenced by local temperature variations, in particular variations due to solar heat gain. In the Gondomar structure, deformation and cavity expansion were greatest in parts of the structure with a southern aspect, where the summer temperatures of the veneer are highest. The influence of aspect here is presumably exacerbated by the open situation of the building and by the insulation of the cavity where large temperature gradients might be expected. The discussers believe this large gradient acting over a thin veneer may partly explain such dramatic damage over a short period of time. A thicker brick cladding would probably fare better. Undoubtedly, there are also seasonal modulations of the expansion. The discussers have shown elsewhere how related thermal effects in the rehydroxylation of archaeological ceramics may be calculated (Hall et al. 2013)