Parting the Waters of Bondage: African Americans’ Aquatic Heritage

Since the 1960s, when the United States Center for Disease Control began compiling racial statistics on drowning death rates, it has been painfully obvious that African Americans are far more likely to drown than their white counterparts. While segregation denied black people access to most public swimming pools and racial violence transformed natural waterways into undesirable places for swimming a leisure, perceptions that swimming as an “un-black” or “white” pursuit have marginalized its acceptability within African American communities. “Parting the Waters of Bondage” is an original article based on decades of the author’s historical scholarship. It seeks to reduce the African American drowning death rate by documenting how slaves recreated African aquatic traditions in America, transforming New World waters into places of social, cultural, and spiritual meaning that reflected African valuations. The author has collaborated with swimming advocates across the United States to present this history in a manner that dispels misperceptions that have discouraged black swimming. This article, is written for scholars, as well as lay readers and educators with the objective of providing all with the knowledge to empower African Americans to take pride in and enjoy the aquatic traditions that their ancestors carried to America

Jigsaws and Jugglers: Disposition, Discourse, and Decision-making in the Assessment of Student Nurse Practice

This research is concerned with the assessment of student nurses' practice, implementation of which has been considered problematic since the move of initial training into higher education. It examines clinical nurses' accounts of assessment, and rejects an approach based on identification of competencies as too rationalistic for a situated practice. Insights from, in particular, Foucault, Deleuze, and Derrida were used to analyse practitioners' alternative discourse of practice, and the processes of self-constitution and decision-making. Eighteen practitioners from different settings were interviewed in depth about how they determine acceptable performance. Three participants were interviewed twice to develop ideas arising from the first round of conversations. Practitioners' accounts challenged the conventional understanding of assessment, and the construction of practice implicit in current policy. The analysis suggests a more fluid, un-predetermined understanding, characterised by hesitation and uncertainty, though without losing a concern with safe practice. Several implications for policy and practice are presented. These require a shift of authority towards practitioners' situated judgements and away from predetermined outcomes, both in respect of programme planning and policy guidelines on the specification of standards. A new alliance is proposed to encourage a more authentic engagement with the process from both clinical and educational practitioners

A comparison of enhancement techniques for footwear impressions on dark and patterned fabrics

The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualisation difficulties. A range of readily available chemical and lighting techniques were utilised to enhance footwear impressions made in blood, soil and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualisation as non-fluorescent techniques provided little or no contrast with the background. Occasionally this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood, however the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualisation and fluorescent enhancement on porous substrates such as fabrics is possible

Chemical enhancement of soil based footwear impressions on fabric

This study investigates the enhancement of footwear impressions prepared with soils from different locations on a variety of fabric surfaces with different morphology. Preliminary experiments using seventeen techniques were carried out and the best responding reagents were evaluated further. Results indicated that the soils investigated (a cross-section of soils from Scotland) are more likely to respond to reagents that target iron ions rather than calcium, aluminium or phosphorus ions. Furthermore, the concentration of iron and soil pH did not appear to have an effect on the performance of the enhancement techniques. For the techniques tested, colour enhancement was observed on all light coloured substrates while enhancement on dark coloured fabrics, denim and leatherette was limited due to poor contrast with the background. Of the chemical enhancement reagents tested, 2,20-dipyridil was a suitable replacement for the more common enhancement technique using potassium thiocyanate. The main advantages are the use of less toxic and flammable solvents and improved clarity and sharpness of the enhanced impression. The surface morphology of the fabrics did not have a significant effect on the enhancement ability of the reagents apart from a slight tendency for diffusion to occur on less porous fabrics such as polyester and nylon/lycra blends

On non-normality and classification of amplification mechanisms in stability and resolvent analysis

We seek to quantify non-normality of the most amplified resolvent modes and predict their features based on the characteristics of the base or mean velocity profile. A 2-by-2 model linear Navier-Stokes (LNS) operator illustrates how non-normality from mean shear distributes perturbation energy in different velocity components of the forcing and response modes. The inverse of their inner product, which is unity for a purely normal mechanism, is proposed as a measure to quantify non-normality. In flows where there is downstream spatial dependence of the base/mean, mean flow advection separates the spatial support of forcing and response modes which impacts the inner product. Success of mean stability analysis depends on the normality of amplification. If the amplification is normal, the resolvent operator written in its dyadic representation reveals that the adjoint and forward stability modes are proportional to the forcing and response resolvent modes. If the amplification is non-normal, then resolvent analysis is required to understand the origin of observed flow structures. Eigenspectra and pseudospectra are used to characterize these phenomena. Two test cases are studied: low Reynolds number cylinder flow and turbulent channel flow. The first deals mainly with normal mechanisms and quantification of non-normality using the inverse inner product of the leading forcing and response modes agrees well with the product of the resolvent norm and distance between the imaginary axis and least stable eigenvalue. In turbulent channel flow, structures result from both normal and non-normal mechanisms. Mean shear is exploited most efficiently by stationary disturbances while bounds on the pseudospectra illustrate how non-normality is responsible for the most amplified disturbances at spatial wavenumbers and temporal frequencies corresponding to well-known turbulent structures

Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO₂ concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO₂ concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO₂ on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO₂ assimilation rate over the diurnal course of evaporative demand

Exploring IT-Enabled Public Sector Innovation in U.S. States

Scholars and practitioners often assume that the public sector mirrors the private sector and that it is possible to merely port strategies between domains. However, we highlight the substantial differences between the domains and explore how IT-enabled innovation shapes and is shaped within state government. Analyzing state-level IT governance data using crisp-set Qualitative Comparative Analysis, we uncover that low state attainment is a catalyst for IT-enabled innovation. We uncover and differentiate several types of innovations and also find that successful innovation requires the collaboration of the legislature, governor and CIO