1,519 research outputs found
Management by Textbook: The Role of Textbooks in Developing Critical Thinking
© 2015, © The Author(s) 2015. Critical thinking is widely regarded as a crucial capability for competent management and also for any leadership role in society. In this article, we ask, âHow do textbooks play a role in the weakness of many management graduatesâ critical thinking skills?â Management teachers can find plentiful advice about best teaching practices, yet the critical skills gap remains. We argue that the nature and use of management textbooks intersect and interact with studentsâ epistemology to support a culture of surface learning, resulting in a failure to develop critical thinking skills. Textbooks reinforce underdeveloped student epistemology through limitations of content and position students as passive recipients of an authoritative version of oversimplified knowledge. In our survey of 30 successful management textbooks, we found the majority of popular management textbooks potentially inhibit, or only weakly support, the development of studentsâ capacity for critical thinking. The article concludes with suggestions for improving textbooks and textbook choice or considering alternatives
Using Available Volume to Predict Fluid Diffusivity in Random Media
We propose a simple equation for predicting self-diffusivity of fluids
embedded in random matrices of identical, but dynamically frozen, particles
(i.e., quenched-annealed systems). The only nontrivial input is the volume
available to mobile particles, which also can be predicted for two common
matrix types that reflect equilibrium and non-equilibrium fluid structures. The
proposed equation can account for the large differences in mobility exhibited
by quenched-annealed systems with indistinguishable static pair correlations,
illustrating the key role that available volume plays in transport.Comment: to appear in Physical Review E (12 pages, 4 figures
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Ultrastructural Distribution of the 7 Nicotinic Acetylcholine Receptor Subunit in Rat Hippocampus
Acetylcholine (ACh) is an important neurotransmitter in the mammalian brain; it is implicated in arousal, learning, and other cognitive functions. Recent studies indicate that nicotinic receptors contribute to these cholinergic effects, in addition to the established role of muscarinic receptors. In the hippocampus, where cholinergic involvement in learning and memory is particularly well documented, 7 nicotinic acetylcholine receptor subunits (7 nAChRs) are highly expressed, but their precise ultrastructural localization has not been determined. Here, we describe the results of immunogold labeling of serial ultrathin sections through stratum radiatum of area CA1 in the rat. Using both anti-7 nAChR immunolabeling and -bungarotoxin binding, we find that 7 nAChRs are present at nearly all synapses in CA1 stratum radiatum, with immunolabeling present at both presynaptic and postsynaptic elements. Morphological considerations and double immunolabeling indicate that GABAergic as well as glutamatergic synapses bear 7 nAChRs, at densities approaching those observed for glutamate receptors in CA1 stratum radiatum. Postsynaptically, 7 nAChRs often are distributed at dendritic spines in a perisynaptic annulus. In the postsynaptic cytoplasm, immunolabeling is associated with spine apparatus and other membranous structures, suggesting that 7 nAChRs may undergo dynamic regulation, with insertion into the synapse and subsequent internalization. The widespread and substantial expression of 7 nAChRs at synapses in the hippocampus is consistent with an important role in mediating and/or modulating synaptic transmission, plasticity, and neurodegeneration
Control of Cell Morphogenesis in Bacteria Two Distinct Ways to Make a Rod-Shaped Cell
AbstractCell shape in most eubacteria is maintained by a tough external peptidoglycan cell wall. Recently, cell shape determining proteins of the MreB family were shown to form helical, actin-like cables in the cell. We used a fluorescent derivative of the antibiotic vancomycin as a probe for nascent peptidoglycan synthesis in unfixed cells of various Gram-positive bacteria. In the rod-shaped bacterium B. subtilis, synthesis of the cylindrical part of the cell wall occurs in a helical pattern governed by an MreB homolog, Mbl. However, a few rod-shaped bacteria have no MreB system. Here, a rod-like shape can be achieved by a completely different mechanism based on use of polar growth zones derived from the division machinery. These results provide insights into the diverse molecular strategies used by bacteria to control their cellular morphology, as well as suggesting ways in which these strategies may impact on growth rates and cell envelope structure
Interplay between structure and density anomaly for an isotropic core-softened ramp-like potential
Using molecular dynamics simulations and integral equations we investigate
the structure, the thermodynamics and the dynamics of a system of particles
interacting through a continuous core- softened ramp-like interparticle
potential. We found density, dynamic and structural anomalies similar to that
found in water. Analysis of the radial distribution function for several
temperatures at fixed densities show a pattern that may be related to the
origin of density anomaly.Comment: 7 pages, 3 figure
Orientational correlations in confined DNA
We study how the orientational correlations of DNA confined to nanochannels
depend on the channel diameter D by means of Monte Carlo simulations and a
mean-field theory. This theory describes DNA conformations in the
experimentally relevant regime where the Flory-de Gennes theory does not apply.
We show how local correlations determine the dependence of the end-to-end
distance of the DNA molecule upon D. Tapered nanochannels provide the necessary
resolution in D to study experimentally how the extension of confined DNA
molecules depends upon D. Our experimental and theoretical results are in
qualitative agreement.Comment: Revised version including supplemental material, 7 pages, 8 figure
A coupled drug kinetics-cell cycle model to analyse the response of human cells to intervention by topotecan
A model describing the response of the growth of single human cells in the absence and presence of the anti-cancer agent topotecan (TPT) is presented. The model includes a novel coupling of both the kinetics of TPT and cell cycle responses to the agent. By linking the models in this way, rather than using separate (disjoint) approaches, it is possible to illustrate how the drug perturbs the cell cycle. The model is compared to experimental in vitro cell cycle response data (comprising single cell descriptors for molecular and behavioural events), showing good qualitative agreement for a range of TPT dose levels
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A randomized trial of a lab-embedded discourse intervention to improve research ethics.
We report a randomized trial of a research ethics training intervention designed to enhance ethics communication in university science and engineering laboratories, focusing specifically on authorship and data management. The intervention is a project-based research ethics curriculum that was designed to enhance the ability of science and engineering research laboratory members to engage in reason giving and interpersonal communication necessary for ethical practice. The randomized trial was fielded in active faculty-led laboratories at two US research-intensive institutions. Here, we show that laboratory members perceived improvements in the quality of discourse on research ethics within their laboratories and enhanced awareness of the relevance and reasons for that discourse for their work as measured by a survey administered over 4 mo after the intervention. This training represents a paradigm shift compared with more typical module-based or classroom ethics instruction that is divorced from the everyday workflow and practices within laboratories and is designed to cultivate a campus culture of ethical science and engineering research in the very work settings where laboratory members interact
Targeting protein homeostasis with nelfinavir/salinomycin dual therapy effectively
Uncontrolled cell growth in Tuberous Sclerosis Complex occurs due to
inappropriate activation of mechanistic (mammalian) target of rapamycin complex
1 (mTORC1). The current therapy, rapamycin, produced promising clinical trial
results, but patient tumours regrow if treatment is discontinued, revealing rapamycin
has cytostatic properties rather than a cytotoxic effect. Taking advantage of the
enhanced levels of endoplasmic reticulum (ER) stress present in TSC2-null cells, we
investigated drug combinations producing a cytotoxic response. We found a nelfinavir
and salinomycin combination specifically killed TSC2-deficient, mTORC1 hyperactive
cells. Cytotoxicity was rescued by reducing protein synthesis, either through mTORC1
inhibition or cycloheximide treatment. This indicates that the drug combination targets
the cells by tipping the protein homeostasis balance of the already metabolically
stressed TSC2-deficient cells in favour of cell death. Furthermore, this drug
combination also inhibited tumour formation in TSC2-deficient cell models and caused
tumour spheroid death in 3D culture. Importantly, the 3D assay could differentiate the
cytostatic agent, rapamycin, from the cytotoxic nelfinavir/salinomycin combination.
Sporadic cancer cell lines with hyperactive mTORC1 signalling were also susceptible
to this nelfinavir/salinomycin drug combination. This work indicates that the protein
homeostasis pathway is an attractive therapeutic target in both Tuberous Sclerosis
Complex and mTORC1-driven sporadic cancers
Which mechanism underlies the water-like anomalies in core-softened potentials?
Using molecular dynamics simulations we investigate the thermodynamic of
particles interacting with a continuous and a discrete versions of a
core-softened (CS) intermolecular potential composed by a repulsive shoulder.
Dynamic and structural properties are also analyzed by the simulations. We show
that in the continuous version of the CS potential the density at constant
pressure has a maximum for a certain temperature. Similarly the diffusion
constant, , at a constant temperature has a maximum at a density
and a minimum at a density
, and structural properties are also
anomalous. For the discrete CS potential none of these anomalies are observed.
The absence of anomalies in the discrete case and its presence in the
continuous CS potential are discussed in the framework of the excess entropy.Comment: 8 page
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