Search results for "HTN"
showing 10 items of 252 documents
Two simple criteria to estimate an objective's performance when imaging in non design tissue clearing solutions
2019
Tissue clearing techniques are undergoing a renaissance motivated by the need to image fluorescent neurons, and other cells, deep in the sample without physical sectioning. Optical transparency is achieved by equilibrating tissues with high refractive index (RI) solutions. When the microscope objective is not perfectly matched to the RI of the cleared sample, aberrations are introduced. We present two simple-to-calculate numerical criteria predicting: (i) the degradation in image quality (brightness and resolution) from optimal conditions of any clearing solution/objective combination; (ii) which objective, among several available, achieves the highest resolution in a given medium. We deriv…
Variations of selective separability II: Discrete sets and the influence of convergence and maximality
2012
A space $X$ is called selectively separable(R-separable) if for every sequence of dense subspaces $(D_n : n\in\omega)$ one can pick finite (respectively, one-point) subsets $F_n\subset D_n$ such that $\bigcup_{n\in\omega}F_n$ is dense in $X$. These properties are much stronger than separability, but are equivalent to it in the presence of certain convergence properties. For example, we show that every Hausdorff separable radial space is R-separable and note that neither separable sequential nor separable Whyburn spaces have to be selectively separable. A space is called \emph{d-separable} if it has a dense $\sigma$-discrete subspace. We call a space $X$ D-separable if for every sequence of …
Sublimation of icy aggregates in the coma of comet 67P/Churyumov–Gerasimenko detected with the OSIRIS cameras on board Rosetta
2016
Beginning in 2014 March, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov¿Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet's dust jets. We analysed the dust monitoring observations shortly after the southern vernal equinox on 2015 May 30 and 31 with the WAC at the heliocentric distance Rh = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness a…
Lightning-ignited wildfires and long continuing current lightning in the Mediterranean Basin: Preferential meteorological conditions
2021
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
2020
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society.--All authors: Kim, Jae-Young; Krichbaum, Thomas P.; Broderick, Avery E.; Wielgus, Maciek; Blackburn, Lindy; Gómez, José L.; Johnson, Michael D.; Bouman, Katherine L.; Chael, Andrew; Akiyama, Kazunori; Jorstad, Svetlana; Marscher, Alan P.; Issaoun, Sara; Janssen, Michael; Chan, Chi-kwan; Savolainen, Tuomas; Pesce, Dominic W.; Özel, Feryal; Alberdi, Antxon; Alef, Walt…
DISTRIBUTION OF CARBON STARS IN THE GALAXY
2018
A search for new faint carbon (C) stars in the Polar region δ > 55o has been accomplished by obtaining objective prism spectra in the near infrared 550 -- 900 nm on images of CCD camera of Baldone Schmidt telescope of Astrophysical observatory. The positions of stars having color indices (J – K) > 1.3 mag in Two Micron All Sky Infrared Survey (2MASS) were selected to pick out suspicious carbon stars.Our survey is limited in brightness by J < 10 mag. 24 new carbon stars were found and their characteristics obtained. The correlative relation between Teff and spectral gradient [757 – 685] was confirmed. Such characteristics as Teff, distance from the Sun, absolute Mk were obtained…
Which Attribute of Ceiling Color Influences Perceived Room Height?
2018
Objective:We investigate effects of the hue, saturation, and luminance of ceiling color on the perceived height of interior spaces.Background:Previous studies have reported that the perceived height of an interior space is influenced by the luminance of the ceiling, but not by the luminance contrast between ceiling and walls: brighter ceilings appeared higher than darker ceilings, irrespective of wall and floor luminance. However, these studies used solely achromatic colors. We report an experiment in which we extend these findings to effects of chromatic ceiling colors.Methods:We presented stereoscopic room simulations on a head-mounted display (Oculus Rift DK2) and varied hue (red, green,…
Differences between tight and loose cultures: a 33-nation study.
2011
With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention …
Influence of stimulus color on the control of reaching-grasping movements.
2001
This kinematic study aimed to determine whether color is a stimulus property involved in the control of reaching-grasping movements. Subjects reached and grasped a target-object, located either on the right or on the left of the subject's midline. A distractor, placed along the subject's midline, could be randomly presented. The colors, i.e., both chromaticity (red and green stimuli were presented) and lightness, of the target and distractor were varied in experiment 1. Only stimulus lightness and only stimulus chromaticity were varied in experiments 2 and 3, respectively. In experiment 4 subjects matched with their thumb and index finger the size of the target-stimuli presented in experime…
Surface Lightness Influences Perceived Room Height
2010
Surprisingly little scientific research has been conducted on the effects of colour and lightness on the perception of spaciousness. Practitioners and architects typically suggest that a room's ceiling appears higher when it is painted lighter than the walls, while darker ceilings appear lower. Employing a virtual reality setting, we studied the effects of the lightness of different room surfaces on perceived height in two psychophysical experiments. Observers judged the height of rooms varying in physical height as well as in the lightness of ceiling, floor, and walls. Experiment 1 showed the expected increase of perceived height with increases in ceiling lightness. Unexpectedly, the perce…