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

Quenched QCD at finite density

Simulations of quenched $QCD$ at relatively small but {\it nonzero} chemical potential $\mu$ on $32 \times 16^3$ lattices indicate that the nucleon screening mass decreases linearly as $\mu$ increases predicting a critical chemical potential of one third the nucleon mass, $m_N/3$, by extrapolation. The meson spectrum does not change as $\mu$ increases over the same range, from zero to $m_\pi/2$. Past studies of quenched lattice QCD have suggested that there is phase transition at $\mu = m_\pi/2$. We provide alternative explanations for these results, and find a number of technical reasons why standard lattice simulation techniques suffer from greatly enhanced fluctuations and finite size effects for $\mu$ ranging from $m_\pi/2$ to $m_N/3$. We find evidence for such problems in our simulations, and suggest that they can be surmounted by improved measurement techniques.Comment: 23 pages, Revte

Identification of Hispanic American Students and Students of Poverty for Gifted and Talented Programs

For decades, experts have discussed an educational gap between Anglo Americans and Culturally Diverse Americans. While this gap is apparent in scores on standardized tests, it is also observed in the underrepresentation of culturally different students identified for gifted and talented programs. A PowerPoint presentation was developed to inform both novice and experienced educators of: (a) current means of identification of gifted and talented students, (b) demographics that indicate change is needed, and (c) changes that may reduce the underrepresentation of Hispanic American and impoverished students in gifted and talented programs. It is the belief of this researcher that, with information and training, educators can eliminate underrepresentation and better serve all students

An electro-chemo-mechanical framework for predicting hydrogen uptake in metals due to aqueous electrolytes

We present a theoretical and numerical scheme that enables quantifying hydrogen ingress in metals for arbitrary environments and defect geometries. This is achieved by explicitly resolving the electrochemical behaviour of the electrolyte, the hydrogen and corrosion reactions, the kinetics of surface adsorption, and hydrogen uptake, diffusion and trapping in mechanically-deforming solids. This new framework is used to produce maps that relate the absorbed hydrogen with the applied potential, specimen geometry and fluid velocity. We also present simplified versions of our generalised model, and benchmark predictions of these and other existing models against the generalised electro-chemo-mechanical results, establishing regimes of validity

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

The effects of dietary fish oil on exercising skeletal muscle vascular and metabolic control in chronic heart failure rats

The ATP-sensitive K+ (KATP) channel is a class of inward rectifier K+ channels that can link cellular metabolic status to vasomotor tone across the metabolic transients seen with exercise. This investigation tested the hypothesis that if KATP channels are crucial to exercise hyperaemia then blockade via glibenclamide (GLI) would lower hindlimb skeletal muscle blood flow (BF) and vascular conductance (VC) during treadmill exercise. In 14 adult male Sprague Dawley rats mean arterial pressure (MAP), blood [lactate], and hindlimb muscle BF (radiolabelled microspheres) were determined at rest (n = 6) or during exercise (n = 8; 20 m min⁻¹, 5% incline) under control (CON) and GLI conditions (5 mg kg⁻¹, i.a). At rest and during exercise, MAP was higher (Rest, CON: 130 ± 6, GLI: 152 ± 8; Exercise, CON: 140 ± 4, GLI: 147 ± 4 mmHg, P < 0.05) and heart rate (HR) was lower (Rest, CON: 440 ± 16, GLI: 410 ± 18; Exercise, CON: 560 ± 4, GLI: 540 ± 10 beats min⁻¹, P < 0.05) with GLI. Hindlimb muscle BF (CON: 144 ± 10, GLI: 120 ± 9 ml min⁻¹ (100 g)⁻¹, P < 0.05) and VC were lower with GLI during exercise but not at rest. Specifically, GLI decreased BF in 12, and VC in 16, of the 28 individual hindlimb muscles and muscle parts sampled during exercise with a greater fractional reduction present in muscles comprised predominantly of type I and type IIa fibres (P < 0.05). Additionally, blood [lactate] (CON: 2.0 ± 0.3; GLI: 4.1 ± 0.9 mmol L⁻¹, P < 0.05) was higher during exercise with GLI. That KATP channel blockade reduces hindlimb muscle BF during exercise in rats supports the obligatory contribution of KATP channels in large muscle mass exercise-induced hyperaemia

Information Literacy and the Transition from High School to College

What expectations should college librarians have concerning the information literacy skills of incoming freshmen? This has been a recurring question among college librarians for years. The complementary question for high school librarians is: what do colleges expect freshmen to know in order to be effective researchers? AASL and ACRL have published information literacy standards, and have worked cooperatively to encourage communication between high school and college librarians. Have these efforts been successful? In this article, the authors share information about their research study exploring whether a gap exists between high school and college expectations related to information literacy. The authors conducted a study of Catholic high school librarians in Minnesota and neighboring states during the 2009‐10 school year. They conducted a survey and interviews with the librarians and gathered information about the reference resources available (print and online) and the information literacy skills of high school students, especially seniors. The hypotheses of the study include: Larger schools (over 500 enrollment) are more likely to have: 1) a full‐time media specialist able to develop collections and programs; 2) more comprehensive reference collections and more online resources; 3) a formal curriculum for information literacy instruction; and 4) students receiving a formal curriculum will rank higher in information literacy skill levels. The researchers found that the size of the student body is not the critical factor for a successful IL program. Regardless of the size of the school or library staff, the key factor for success according to the data is the integration of the librarian and IL concepts into a few key core courses. The interviews revealed that it is important for the librarian to have general knowledge of what is taught in various classes, as well as knowledge of specific assignments with a research component. It is evident from the librarians’ comments that it is crucial for the librarian to have a flexible schedule in order to accommodate working with students and teachers. Librarians in the study reported much higher interaction rates with the students when computers and other technologies, including special software and smartboards, are located in an adjacent lab or in the library itself

NOVEL ACRYLIC PARTICLE TECHNOLOGY

The Dow Chemical Company has developed a novel acrylic technology for use in leather finishing formulations. Products making use of this unique technology can deliver low gloss finishes with high optical clarity, soft-touch aesthetics and high physical performance. The key enabler in this technology is an acrylic particle that offers comparable gloss, “jetness” and performance properties to many commercially available inorganic and organic dulling materials. The technology is inherently solvent free, and is compatible with existing acrylic and polyurethane resin components as well as conventional cross-linking chemistries. RESUMENThe Dow Chemical Company ha desarrollado una nueva tecnología de acrílicos para su uso en formulaciones de acabados de cueros. Los productos que hacen uso de esta tecnología única pueden ofrecer acabados de bajo brillo con alta claridad óptica, suave al tacto y altos valores físicos. El elemento clave en esta tecnología es una partícula de acrílico que ofrece un brillo comparable, negros muy intensos, y altas propiedades a varios materiales mateantes orgánicos e inorgánicos disponibles en el mercado. La tecnología es inherentemente libre de solventes, y es compatible con componentes resínicos acrílicos y poliuretanicos como así con la química convencional de reticulantes