1,038 research outputs found

    The dog or its muzzle as a signal of danger to humans?

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    In France, dogs of specific breeds as well as dogs trained to attack (police, security services, etc.) have to be muzzled in public areas. A dog wearing a muzzle may constitute an ambiguous cue for humans as it indicates that the dog is potentially dangerous while at the same time that the dog’s potential danger is controlled. The aim of our present study was to determine whether a muzzled dog would induce a greater fear response in humans than the same non-muzzled dog. We were interested specifically in the German shepherd dog as it is one of the typical breeds used by police and security services, but also very popular as a pet

    One Course May Not Fit All: Online Accounting Course Offerings

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    Distance (i.e., online) education has become an increasingly popular form of higher-education instruction. A Pew Research Center survey conducted in 2011 revealed that a majority of colleges and universities now offer online courses; this trend was most pervasive among public universities (at 89 percent). Online (vs. in-class) instruction is considered more cost effective and has the potential to educate larger portions of the population. However, while some prior studies have focused on the efficacy of various educational delivery methods, some self-selection bias has generally been present in comparisons of online and traditional, in-classroom instruction. This paper provides preliminary evidence about the outcomes when students are not allowed to self-select between online and traditional instruction for an upper-level accounting course and instead are offered only an online course; our results suggest that when students are provided with this option, their exam performance and instructor-evaluation scores are higher. This suggests that upper-level accounting students self-select well between online and traditional instruction and that online education is not suitable for all students. This should be important to academic institutions and accounting researchers as we continue to explore issues pertaining to online educatio

    Involvement of electrical signalling in theta frequency oscillations generated in the medial septum/diagonal band of Broca in vitro

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    Theta frequency (4 – 15 Hz) extracellular field activity can be reliably and repeatedly evoked in the medial septum/diagonal band of Broca (MS/DB) in vitro by the application of kainate. We have previously demonstrated a critical role for inhibitory neurotransmission in the maintenance of this activity and presented data that indicates parvalbumin GABAergic neurons are responsible for pacing rhythmic theta activity in the MS/DB. Evidence of functional electrical coupling between GABAergic interneurons has been reported in the hippocampus and neocortex and it has recently become clear that gap junctions may have a significant function in the generation of neuronal population activity. Here we demonstrate that application of the gap-junction uncoupling agent carbenoxolone causes a significant reduction (P< 0.05, Paired T test) in the kainate induced activity recorded at theta frequency (spectral integral in 4-15 Hz range) in the MS/DB slice in vitro. MS/DB slices were prepared from male Wistar rats (21 days), which were terminally anaesthetised with pentobarbitone sodium (120 mg.kg-1, i.p.). The animals were transcardially perfused with ~ 25ml of modified ACSF and rapidly decapitated. Longitudinal slices (450 ”m) were placed in an interface recording chamber and maintained at 32°C. Persistent theta oscillations were induced by bath application of 100 nM kainate. Carbenoxolone was bath applied to stabilized kainate induced activity at a concentration of 100 ÎŒM for 60 minutes. At 60 minutes there was a significant reduction in the theta frequency activity recorded (56.6% ± 2.3) and in peak amplitude (n = 6). These results indicate a pivotal role for electrical signalling in the theta frequency rhythmic activity induced in the MS/DB upon application of kainate

    Involvement of electrical signalling in theta frequency oscillations generated in the medial septum/diagonal band of Broca in vitro

    Get PDF
    Theta frequency (4 – 15 Hz) extracellular field activity can be reliably and repeatedly evoked in the medial septum/diagonal band of Broca (MS/DB) in vitro by the application of kainate. We have previously demonstrated a critical role for inhibitory neurotransmission in the maintenance of this activity and presented data that indicates parvalbumin GABAergic neurons are responsible for pacing rhythmic theta activity in the MS/DB. Evidence of functional electrical coupling between GABAergic interneurons has been reported in the hippocampus and neocortex and it has recently become clear that gap junctions may have a significant function in the generation of neuronal population activity. Here we demonstrate that application of the gap-junction uncoupling agent carbenoxolone causes a significant reduction (P< 0.05, Paired T test) in the kainate induced activity recorded at theta frequency (spectral integral in 4-15 Hz range) in the MS/DB slice in vitro. MS/DB slices were prepared from male Wistar rats (21 days), which were terminally anaesthetised with pentobarbitone sodium (120 mg.kg-1, i.p.). The animals were transcardially perfused with ~ 25ml of modified ACSF and rapidly decapitated. Longitudinal slices (450 ”m) were placed in an interface recording chamber and maintained at 32°C. Persistent theta oscillations were induced by bath application of 100 nM kainate. Carbenoxolone was bath applied to stabilized kainate induced activity at a concentration of 100 ÎŒM for 60 minutes. At 60 minutes there was a significant reduction in the theta frequency activity recorded (56.6% ± 2.3) and in peak amplitude (n = 6). These results indicate a pivotal role for electrical signalling in the theta frequency rhythmic activity induced in the MS/DB upon application of kainate

    Attribution of recent temperature behaviour reassessed by a neural-network method

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    Abstract Attribution studies on recent global warming by Global Climate Model (GCM) ensembles converge in showing the fundamental role of anthropogenic forcings as primary drivers of temperature in the last half century. However, despite their differences, all these models pertain to the same dynamical approach and come from a common ancestor, so that their very similar results in attribution studies are not surprising and cannot be considered as a clear proof of robustness of the results themselves. Thus, here we adopt a completely different, non-dynamical, data-driven and fully nonlinear approach to the attribution problem. By means of neural network (NN) modelling, and analysing the last 160 years, we perform attribution experiments and find that the strong increase in global temperature of the last half century may be attributed basically to anthropogenic forcings (with details on their specific contributions), while the Sun considerably influences the period 1910–1975. Furthermore, the role of sulphate aerosols and Atlantic Multidecadal Oscillation for better catching interannual to decadal temperature variability is clarified. Sensitivity analyses to forcing changes are also performed. The NN outcomes both corroborate our previous knowledge from GCMs and give new insight into the relative contributions of external forcings and internal variability to climate

    NMDA receptor content of synapses in stratum radiatum of the hippocampal CA1 area

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    Glutamate receptors activated by NMDA (NMDARs) or AMPA (AMPARs) are clustered on dendritic spines of pyramidal cells. Both the AMPAR-mediated postsynaptic responses and the synaptic AMPAR immunoreactivity show a large intersynapse variability. Postsynaptic responses mediated by NMDARs show less variability. To assess the variability in NMDAR content and the extent of their coexistence with AMPARs in Schaffer collateral-commissural synapses of adult rat CA1 pyramidal cells, electron microscopic immunogold localization of receptors has been used. Immunoreactivity of NMDARs was detected in virtually all synapses on spines, but AMPARs were undetectable, on average, in 12% of synapses. A proportion of synapses had a very high AMPAR content relative to the mean content, resulting in a distribution more skewed toward larger values than that of NMDARs. The variability of synaptic NMDAR content [coefficient of variation (CV), 0.64-0.70] was much lower than that of the AMPAR content (CV, 1.17-1.45). Unlike the AMPAR content, the NMDAR content showed only a weak correlation with synapse size. As reported previously for AMPARs, the immunoreactivity of NMDARs was also associated with the spine apparatus within spines. The results demonstrate that the majority of the synapses made by CA3 pyramidal cells onto spines of CA1 pyramids express both NMDARs and AMPARs, but with variable ratios. A less-variable NMDAR content is accompanied by a wide variability of AMPAR content, indicating that the regulation of expression of the two receptors is not closely linked. These findings support reports that fast excitatory transmission at some of these synapses is mediated by activation mainly of NMDARs

    Solar sail capture trajectories at Mercury

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    Mercury is an ideal environment for future planetary exploration by solar sail since it has proved difficult to reach with conventional propulsion and hence remains largely unexplored. In addition, its proximity to the Sun provides a solar sail acceleration of order ten times the sail characteristic acceleration at 1 AU. Conventional capture techniques are shown to be unsuitable for solar sails and a new method is presented. It is shown that capture is bound by upper and lower limits on the orbital elements of the approach orbit and that failure to be within limits results in a catastrophic collision with the planet. These limits are presented for a range of capture inclinations and sail characteristic accelerations. It is found that sail hyperbolic excess velocity is a critical parameter during capture at Mercury, with only a narrow allowed band in order to avoid collision with the planet. The new capture methodis demonstrated for a Mercury sample return mission
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