Viscous Decoupling Transitions for Individually Dragged Particles in Systems with Quenched Disorder

We show that when an individual particle is dragged through an assembly of other particles in the presence of quenched disorder, a viscous decoupling transition occurs between the dragged particle and the surrounding particles which is controlled by the quenched disorder. A counterintuitive consequence of this transition is that the velocity of the dragged particle can be increased by increasing the strength or density of the quenched disorder. The decoupling transition can also occur when the external drive on the dragged particle is increased, and is observable as a clear signature in the velocity-force response.Comment: 4 pages, 3 postscript figure

Dorsal and anal pterygiophore interdigitation patterns in four species of Morone (Teleostei, Percichthyidae) : an aid to larval identification

The diagnostic potential of dorsal and anal pterygiophore interdigitation patterns was examined in larval stages of Morone saxatilis, M. chrysops, M. americana and M.mississippiensis. The number and position of pterygiophores relative to interneural spaces 1-6 and 10-13 and interhaemal spaces 12-15 as well as total number of dorsal and anal pterygiophores are characters useful in delimiting larvae of American Morone species. Interdigitation patterns useful in separating M. mississippiensis and M. americana larvae were not found, however these two species may not co-occur

Practical Art Projects Related to Children’s Picture Books about Ecology

This study presents art projects that reinforce scientific content presented in children’s picture books about ecology. Ten K-6 students from varying socioeconomic classes, and different cultural and language backgrounds from the United States and Spain participated. Next Generation Science Standards were identified and addressed in these art projects. Students’ understanding and engagement were evaluated through teacher observations, photographs, and a student attitude survey. Upper- and lower-elementary students evidenced increased understanding of environmental issues, and high level of enjoyment and engagement through these art projects integrated with science content. Researchers encourage educators to incorporate picture books and art in science lessons to increase student engagement and scientific learning while meeting various standards

A Content Analysis of Thirty Children’s Picture Books about Ecology

This study presents a content analysis of 30 ecology-themed children’s picture books published in English and Spanish from 1994 to the present. Books were analyzed for the following aspects: 1) Nature appreciation, 2) Interrelatedness of Nature, 3) Realistic ecology problem, 4) Differing perspectives, 5) Hope for a solution, 6) Reflection and responsibility, 7) Steps for a solution, 8) Positive tone, 9) Representation of diversity, 10) Appropriate illustrations, 11) Story appeal, and 12) Developmental appropriateness. Scoring guidelines are provided in an appendix. Content analysis results revealed that most books raise awareness about the impact of human action on the environment, although some titles lack important traits such as offering differing perspectives of ecological problems. Researchers encourage educators to incorporate picture books and art in science lessons to increase student engagement and scientific learning while meeting various standards. A companion practical paper in the same issue of the Journal provides example art projects connected to the books

Phleborheography: A Correlative Study with Venography

The Vascular Laboratory of Henry Ford Hospital has used the Cranley-Grass Phleborheograph (PRG) as the primary noninvasive method to determine the presence or absence of deep venous thrombosis (DVT) in the lower limbs since December 1977. In order to determine its proper role and clinical reliability, we compared the diagnostic accuracy of phleborheography with contrast venography. From December 1977 through December 1978, 483 cases (963 limbs) were successfully examined by PRG. Ofthese, 111 cases (216 limbs) also had contrast venography. The PRG was confirmed as normal in 151 out of 157 (6 false negatives). There were 53 abnormal PRCs, with 35 confirmed by venography and 18 false positives. Six PRCs were considered equivocal. Sensitivity on a per limb basis was .85. The overall specificity was .86, and when equivocal examinations were excluded, it was .89. Phleborheography is safe, reliable, widely applicable, and well-tolerated. However, skilled technicians and careful interpretation are essential to its success

Role of transport performance on neuron cell morphology

The compartmental model is a basic tool for studying signal propagation in neurons, and, if the model parameters are adequately defined, it can also be of help in the study of electrical or fluid transport. Here we show that the input resistance, in different networks which simulate the passive properties of neurons, is the result of an interplay between the relevant conductances, morphology and size. These results suggest that neurons must grow in such a way that facilitates the current flow. We propose that power consumption is an important factor by which neurons attain their final morphological appearance.Comment: 9 pages with 3 figures, submitted to Neuroscience Letter

Corrosion rates under charge-conservation conditions

Laboratory and numerical corrosion experiments impose an electric potential on the metal surface, differing from natural corrosion conditions, where corrosion typically occurs in the absence of external current sources. In this work, we present a new computational model that enables predicting corrosion under charge-conservation conditions. The metal potential, an output of the model, is allowed to change, capturing how the corrosion and cathodic reactions must produce/consume electrons at the same rates, as in natural conditions. Finite element simulations are performed over a large range of concentrations and geometric parameters. The results highlight the notable influence of the charge-conservation assumption and pioneeringly quantify corrosion rates under realistic conditions. They further show: (i) the strong coupling between the corrosion rate and the hydrogen and oxygen evolution reactions, (ii) under which circumstances corrosion pits acidify, and (iii) when corrosion is able to become self-sustained lacking oxygen