3,030 research outputs found
Detection thresholds of macaque otolith afferents
The vestibular system is our sixth sense and is important for spatial perception functions, yet the sensory detection and discrimination properties of vestibular neurons remain relatively unexplored. Here we have used signal detection theory to measure detection thresholds of otolith afferents using 1 Hz linear accelerations delivered along three cardinal axes. Direction detection thresholds were measured by comparing mean firing rates centered on response peak and trough (full-cycle thresholds) or by comparing peak/trough firing rates with spontaneous activity (half-cycle thresholds). Thresholds were similar for utricular and saccular afferents, as well as for lateral, fore/aft, and vertical motion directions. When computed along the preferred direction, full-cycle direction detection thresholds were 7.54 and 3.01 cm/s(2) for regular and irregular firing otolith afferents, respectively. Half-cycle thresholds were approximately double, with excitatory thresholds being half as large as inhibitory thresholds. The variability in threshold among afferents was directly related to neuronal gain and did not depend on spike count variance. The exact threshold values depended on both the time window used for spike count analysis and the filtering method used to calculate mean firing rate, although differences between regular and irregular afferent thresholds were independent of analysis parameters. The fact that minimum thresholds measured in macaque otolith afferents are of the same order of magnitude as human behavioral thresholds suggests that the vestibular periphery might determine the limit on our ability to detect or discriminate small differences in head movement, with little noise added during downstream processing
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Modulation of endothelial cell KCa3.1 Channels during endothelium-derived hyperpolarizing factor signaling in mesenteric resistance arteries
Arterial hyperpolarization to acetylcholine (ACh) reflects coactivation of KCa3.1 (IKCa) channels and KCa2.3 (SKCa) channels in the endothelium that transfers through myoendothelial gap junctions and diffusible factor(s) to affect smooth muscle relaxation (endothelium-derived hyperpolarizing factor [EDHF] response). However, ACh can differentially activate KCa3.1 and KCa2.3 channels, and we investigated the mechanisms responsible in rat mesenteric arteries. KCa3.1 channel input to EDHF hyperpolarization was enhanced by reducing external [Ca2+]o but blocked either with forskolin to activate protein kinase A or by limiting smooth muscle [Ca2+]i increases stimulated by phenylephrine depolarization. Imaging [Ca2+]i within the endothelial cell projections forming myoendothelial gap junctions revealed increases in cytoplasmic [Ca2+]i during endothelial stimulation with ACh that were unaffected by simultaneous increases in muscle [Ca2+]i evoked by phenylephrine. If gap junctions were uncoupled, KCa3.1 channels became the predominant input to EDHF hyperpolarization, and relaxation was inhibited with ouabain, implicating a crucial link through Na+/K+-ATPase. There was no evidence for an equivalent link through KCa2.3 channels nor between these channels and the putative EDHF pathway involving natriuretic peptide receptor-C. Reconstruction of confocal z-stack images from pressurized arteries revealed KCa2.3 immunostain at endothelial cell borders, including endothelial cell projections, whereas KCa3.1 channels and Na+/K+-ATPase {alpha}2/{alpha}3 subunits were highly concentrated in endothelial cell projections and adjacent to myoendothelial gap junctions. Thus, extracellular [Ca2+]o appears to modify KCa3.1 channel activity through a protein kinase A-dependent mechanism independent of changes in endothelial [Ca2+]i. The resulting hyperpolarization links to arterial relaxation largely through Na+/K+-ATPase, possibly reflecting K+ acting as an EDHF. In contrast, KCa2.3 hyperpolarization appears mainly to affect relaxation through myoendothelial gap junctions. Overall, these data suggest that K+ and myoendothelial coupling evoke EDHF-mediated relaxation through distinct, definable pathways
Perancangan Interior Fasilitas E-Sports Arena
T This Design's background are the problems of the growth of gaming industries in Indonesia and have been made official by the government that gamers can be national athlete through many steps but they still don't have the place with facilities and appreciation, so this E-Sports facility maximize their potential and change the way people think about the game that gamin isn't just for fun but gaming can be a profession. The implementation of futuristic design will be the furniture and interior elements to create the impression of a futuristic design
Alien Registration- Clayton, Dora J. (Auburn, Androscoggin County)
https://digitalmaine.com/alien_docs/30990/thumbnail.jp
Defining Exploratory-Descriptive Qualitative (EDQ) research and considering its application to healthcare.
This article aims to introduce readers to a distinctive approach to health research when the topic under investigation has received little previous attention. It provides details of the theoretical underpinnings of the methodology, as well as providing recommendations regarding the practicalities of its use. To address a specific research aim, the primary author believed that an exploratory descriptive qualitative approach was the most suitable. A subsequent review of the relevant literature identified a number of published research articles, which claimed to use an "exploratory descriptive qualitative" design. Closer inspection revealed that these papers lacked theoretical underpinning. As a result, the authors created a conceptual framework, underpinned by appropriate theory, to support the use of an exploratory descriptive qualitative approach. We refer to this approach as EDQ and argue that there is a place in health research when it is deemed the most appropriate methodology to achieve the aims of a study
Higher lying resonances in low-energy electron scattering with carbon monoxide
R-matrix calculations on electron collisions with CO are reported whose aim is to identify any higher-lying resonances above the well-reported and lowest 2Π resonance at about 1.6 eV. Extensive tests with respect to basis sets, target models and scattering models are performed. The final results are reported for the larger cc-pVTZ basis set using a 50 state close-coupling (CC) calculation. The Breit-Wigner eigenphase sum and the time-delay methods are used to detect and fit any resonances. Both these methods find a very narrow 2Σ+ symmetry Feshbach-type resonance very close to the target excitation threshold of the b 3Σ+ state which lies at 12.9 eV in the calculations. This resonance is seen in the CC calculation using cc-pVTZ basis set while a CC calculation using the cc-pVDZ basis set does not produce this feature. The electronic structure of CO− is analysed in the asymptotic region; 45 molecular states are found to correlate with states dissociating to an anion and an atom. Electronic structure calculations are used to study the behaviour of these states at large internuclear separation. Quantitative results for the total, elastic and electronic excitation cross sections are also presented. The significance of these results for models of the observed dissociative electron attachment of CO in the 10 eV region is discussed
Disaster assistance: determinants of countries around the world contributing towards disaster donations
Foreign responses after Hurricane Katrina and the Wenchuan and Haiti earthquakes varied. The cluster analysis in this paper shows that 35 countries were preferentially US-oriented, 47 Haiti-oriented, 33 China-oriented, 33 had no explicit orientation and 32 did not offer assistance. Further evidence about geographies of generosity or geopolitical orientation was found, with the North American countries more likely to assist US and the Asian countries - China. Haiti however did not have any particular appeal to North America. The 33 countries found to implement a pure humanitarian approach to disaster aid have higher per capita gross domestic product (GDP) and general government consumption expenditure, indicating that foreign assistance depends on the state of the economy and larger public sector. A country with a higher human development index (HDI) is also more likely to donate. Finally, the paper argues the need for a global information network (GIN) to assist in coordinating disaster activities and improve communication channels
Understanding the Importance of Front Yard Accessibility for Community Building: A Case Study of Subiaco, Western Australia
The residential built form, including open space, provides the physical environment for social interaction. Understanding urban open space, including semi-public and public domains, through the lens of physical accessibility and visual permeability can potentially facilitate the building of a sense of community contributing to a better quality of life. Using an inner-city suburb in Perth, Western Australia as a case study, this research explores the importance of physical accessibility patterns and visual permeability for socialising in semi-public and public domains, such as the front yard and the residential streets. It argues that maintaining a balance between public and private inter-relationship in inner city residential neighbourhoods is important for creating and maintaining a sense of community
Effects of exoplanetary gravity on human locomotor ability
At some point in the future, if mankind hopes to settle planets outside the
Solar System, it will be crucial to determine the range of planetary conditions
under which human beings could survive and function. In this article, we apply
physical considerations to future exoplanetary biology to determine the
limitations which gravity imposes on several systems governing the human body.
Initially, we examine the ultimate limits at which the human skeleton breaks
and muscles become unable to lift the body from the ground. We also produce a
new model for the energetic expenditure of walking, by modelling the leg as an
inverted pendulum. Both approaches conclude that, with rigorous training,
humans could perform normal locomotion at gravity no higher than 4
.Comment: 12 pages, 4 figures, to be published in The Physics Teache
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