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Academic literature on the topic 'Spherical Population'

Author: Grafiati

Published: 8 September 2023

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Journal articles on the topic "Spherical Population"

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Al-Sayyari, Tarfah M., Samah M. Fawzy, and Ahmed A. Al-Saleh. "Corneal spherical aberration in Saudi population." Saudi Journal of Ophthalmology 28, no. 3 (July 2014): 207–13. http://dx.doi.org/10.1016/j.sjopt.2014.03.003.

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Soker, Noam, and Eyal Subag. "A Possible Hidden Population of Spherical Planetary Nebulae." Astronomical Journal 130, no. 6 (December 2005): 2717–24. http://dx.doi.org/10.1086/497295.

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Tobler, W. "Preliminary representation of world population by spherical harmonics." Proceedings of the National Academy of Sciences 89, no. 14 (July 15, 1992): 6262–64. http://dx.doi.org/10.1073/pnas.89.14.6262.

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Tobler, Waldo, Uwe Deichmann, Jon Gottsegen, and Kelly Maloy. "World population in a grid of spherical quadrilaterals." International Journal of Population Geography 3, no. 3 (September 1997): 203–25. http://dx.doi.org/10.1002/(sici)1099-1220(199709)3:3<203::aid-ijpg68>3.0.co;2-c.

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Asano, Hiroki, Takahiro Hiraoka, Yusuke Seki, Teppei Shibata, Hiromi Osada, Takanori Saruta, Natsuko Hatsusaka, et al. "Distribution of corneal spherical aberration in a Tanzanian population." PLOS ONE 14, no. 9 (September 12, 2019): e0222297. http://dx.doi.org/10.1371/journal.pone.0222297.

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Baur, Isabella D., Gerd U. Auffarth, Ramin Khoramnia, and Grzegorz Łabuz. "Spherical Aberration of Astigmatic Corneas in a Cataract Population." Journal of Refractive Surgery 39, no. 8 (August 2023): 532–38. http://dx.doi.org/10.3928/1081597x-20230717-01.

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Purpose: To study the distribution of spherical aberration (SA) in astigmatic corneas in a cataract population and the relationship between magnitude of corneal astigmatism and fourth-order corneal SA. Methods: Data routinely collected using a Scheimpflug camera (Pentacam; Oculus Optikgeräte GmbH) were retrospectively analyzed. Patients with a minimum age of 60 years were included. Total corneal SA (from anterior and posterior corneal surface) was obtained for a 6-mm cor-neal area aligned with the pupil center. Exclusion criteria were insufficient measurement quality, total deviation index (Belin/Ambrósio Deviation) greater than 1.60, and corneal thickness at the thinnest point of less than 490 μm. One eye per patient was chosen randomly. Eyes were divided into low (≤ 1.00 diopters [D]), moderate (> 1.00 to ≤ 2.00 D), and high (> 2.00 D) astigmatism groups according to the Scheimpflug measurements. Results: A total of 528 eyes were included in this analysis. Low astigmatism was found in 129 patients, moderate astigmatism in 265 patients, and high astigmatism in 134 patients. Mean astigmatism was 0.68 ± 0.24, 1.45 ± 0.28, and 2.91 ± 0.95 D in the low, moderate, and high astigmatism groups, respectively. Mean corneal SA in patients with moderate and high astigmatism was higher than in the low astigmatism group. The difference reached the significance level for the comparison of low and high astigmatism groups ( P = .023). The fourth-order SA increased gradually with the magnitude of astigmatism with a slope of 0.015. Conclusions: SA was significantly larger in the cataract population with high corneal astigmatism. The increase of positive sign SA with the magnitude of astigmatism suggests that patients with moderate to high astigmatism may benefit more from intraocular lenses with negative sign SA correction. [ J Refract Surg . 2023;39(8):532–538.]

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Keaveney, Nicola, Laura Boyle, and Matt Redman. "Shaping of Planetary Nebulae by Exoplanets." Galaxies 8, no. 2 (May 14, 2020): 41. http://dx.doi.org/10.3390/galaxies8020041.

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(1) Background: We investigate the hypothesis that exoplanet engulfment can help explain the observed non-spherical planetary nebula population, as a complementary shaping mechanism to the binary hypothesis. The aim is to investigate the extent to which massive planets can explain the population of non-spherical planetary nebulae; (2) Methods: This research utilises a new tool to calculate the planet-fraction of planetary nebulae progenitor stars called simsplash; (3) Results: we conclude that ∼15–30% of non-spherical planetary nebulae around single stars will have a history in which they engulfed a massive planet on the AGB; and (4) Conclusions: Engulfment of massive exoplanets may contribute significantly to the formation of non-spherical planetary nebulae around single stars, yet appears to be insufficient to explain them all.

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Kusztelak, Grzegorz, Adam Lipowski, and Jacek Kucharski. "Population Symmetrization in Genetic Algorithms." Applied Sciences 12, no. 11 (May 27, 2022): 5426. http://dx.doi.org/10.3390/app12115426.

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The paper presents a memetic modification of the classical genetic algorithm by introducing a cyclic symmetrization of the population, symmetrizing the parental points around the current population leader. Such an operator provides a more spherical distribution of the population around the current leader, which significantly improves exploitation. The proposed algorithm was described, illustrated by examples, and theoretically analyzed. Its effectiveness was examined using a recognized benchmark, which includes the continuous functions test set on a multidimensional cube, to be minimized.

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Gordiyenko, O. I., Yu E. Gordiyenko, and V. O. Makedonska. "Estimation of erythrocyte population state by the spherical index distribution." Bioelectrochemistry 62, no. 2 (May 2004): 119–22. http://dx.doi.org/10.1016/j.bioelechem.2003.08.004.

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Fujimoto, Shin-ichiro, Masa-aki Hashimoto, Masaomi Ono, and Kei Kotake. "Nucleosynthesis in neutrino-driven, aspherical Population III supernovae." Proceedings of the International Astronomical Union 7, S279 (April 2011): 237–40. http://dx.doi.org/10.1017/s1743921312012987.

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AbstractWe investigate explosive nucleosynthesis during neutrino-driven, aspherical supernova (SN) explosion aided by standing accretion shock instability (SASI), based on two-dimensional hydrodynamic simulations of the explosion of 11, 15, 20, 25, 30 and 40M⊙ stars with zero metallicity. The magnitude and asymmetry of the explosion energy are estimated with simulations, for a given set of neutrino luminosities and temperatures, not as in the previous study in which the explosion is manually and spherically initiated by means of a thermal bomb or a piston and also some artificial mixing procedures are applied for the estimate of abundances of the SN ejecta.By post-processing calculations with a large nuclear reaction network, we have evaluated abundances and masses of ejecta from the aspherical SNe. We find that matter mixing induced via SASI is important for the abundant production of nuclei with atomic number ≥ 21, in particular Sc, which is underproduced in the spherical models without artificial mixing. We also find that the IMF-averaged abundances are similar to those observed in extremely metal poor stars. However, observed [K/Fe] cannot be reproduced with our aspherical SN models.

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Dissertations / Theses on the topic "Spherical Population"

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PILLAI, Vinoshene. "Intravital two photon clcium imaging of glioblastoma mouse models." Doctoral thesis, Scuola Normale Superiore, 2021. http://hdl.handle.net/11384/109211.

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Book chapters on the topic "Spherical Population"

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Opara, Karol R. "Spherical Model of Population Dynamics in Differential Evolution." In Studies in Computational Intelligence, 23–42. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-8082-3_2.

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Assemlal, Haz-Edine, Jennifer Campbell, Bruce Pike, and Kaleem Siddiqi. "Apparent Intravoxel Fibre Population Dispersion (FPD) Using Spherical Harmonics." In Lecture Notes in Computer Science, 157–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23629-7_20.

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Besozzi, Daniela, and Grzegorz Rozenberg. "Formalizing Spherical Membrane Structures and Membrane Proteins Populations." In Membrane Computing, 18–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11963516_2.

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Blows, Mark, and Bruce Walsh. "Spherical Cows Grazing in Flatland: Constraints to Selection and Adaptation." In Adaptation and Fitness in Animal Populations, 83–101. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-9005-9_6.

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Hernandez-Pajares, M., and J. Nuñez. "The Spherical Harmonics as an Alternative Tool for Determining the Kinematical Parameters of the Local Milky Way." In The Stellar Populations of Galaxies, 431. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2434-8_98.

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Dhang, Partho, Philip Koehler, Roberto Pereira, and Daniel D. Dye II. "Mosquitoes." In Key questions in urban pest management: a study and revision guide, 23–30. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781800620179.0003.

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Abstract This book chapter discusses mosquitoes as deadly disease vectors. Biological control is usually implemented for control of larval populations using predators (e.g. top feeding minnows and copepods) or pathogens and pathogen products (i.e., Bacillus thuringiensis israeliensis and B. sphericus). Genetic control is being implemented by releasing sterilized male mosquitoes (genetically modified, radiation sterilised, or transgenic mosquitoes). It starts with minimizing bites through the use of window screens on houses and animal shelters, and the use of treated bed nets and personal repellents. Habitat modification is a reliable method that eliminates adult resting sites and source reduction of larval development areas.

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Coppens, Philip. "Space Partitioning and Topological Analysis of the Total Charge Density." In X-Ray Charge Densities and Chemical Bonding. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195098235.003.0008.

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In partitioning space in the analysis of a continuous charge distribution, the requirement of locality, formulated by Kurki-Suonio (Kurki-Suonio 1968, 1971; Kurki-Suonio and Salmo 1971), should be preserved. It states that density at a point should be assigned to a center in the proximity of that point. In discrete boundary partitioning schemes, the density at each point is assigned to a specific basin, while in fuzzy boundary partitioning, the density at the point may be assigned to overlapping functions centered at different locations. The least-squares formalisms described in chapter 3 implicitly define a space partitioning scheme, based on the density functions used in the refinement that are each centered on a specific nucleus. Since the density functions are continuous, they overlap, so the fragments interpenetrate rather than meet at a discrete boundary. Such fuzzy boundaries correspond to smoothly varying functions, both in real and reciprocal space, and therefore to well-behaved fragment scattering factors, and reasonable fragment electrostatic moments. The interpenetratingfragment partitioning schemes are related to the Mulliken and Løwdin population analyses of theoretical chemistry. The topological analysis of the total density, developed by Bader and coworkers, leads to a scheme of natural partitioning into atomic basins which each obey the virial theorem. The sum of the energies of the individual atoms defined in this way equals the total energy of the system. While the Bader partitioning was initially developed for the analysis of theoretical densities, it is equally applicable to model densities based on the experimental data. The density obtained from the Fourier transform of the structure factors is generally not suitable for this purpose, because of experimental noise, truncation effects, and thermal smearing. The topological analysis of the density leads to a powerful classification of bonding based on the electron density. It is discussed in the final sections of this chapter. The stockholder partitioning concept is one of the important contributions to charge density analysis made by Hirshfeld (1977b). It defines a continuous sampling function wi(r), which assigns the density among the constituent atoms. The sampling function is based on the spherical-atom promolecule density—the sum of the spherically averaged ground-state atom densities.

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Selvakumar, Raman. "An Update on Radish Breeding Strategies: An Overview." In Plant Breeding - New Perspectives [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108725.

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In tropical, subtropical, and temperate climates, radish (Raphanus sativus L.) is a popular root vegetable. Radish diversity is intense from the eastern Mediterranean to the Caspian Sea. Many radish varieties have varied leaf morphology, root color, size, shape, flavor, vernalization requirements, and maturity times. Early radish variants were long and tapered rather than cylindrical, bulbous, elliptic, or spherical. For black Spanish radish, European-cultivated variety, and Asian-cultivated radish, three separate domestication processes occurred. The original radishes were black, followed by white in the 1500s then red and round in the 1700s. These are R. sativus L. var. radicula (sativus) or R. sativus L. var. niger radishes. Because of protogyny, self-incompatibility, open architecture, and biennial bolting, radish crosses readily. The fundamental methods for using heterotic breeding potential are SI, CMS, and doubled haploids (DH). This chapter discusses the various breeding strategies like inbred line development by the use of self-incompatibility, hybrid development by using male sterility system, population improvement, mutation breeding, haploid breeding, breeding strategies for biotic and abiotic stresses, QTL mapping, and genome wide and genomic tool in radish. Rapid developments in our understanding of advanced biotechnology technologies will increase our ability to identify cultivars and parental lines, check seed genetic purity, analyze phylogenetic links and genetic diversity, and add specific transgenic traits.

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Tuck, Adrian F. "Relevant Subjects." In Atmospheric Turbulence. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780199236534.003.0006.

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Atmospheric composition played an important part in the development of chemistry, following the work of Priestley, Lavoisier, and Dalton. Since air is a mixture of gases, many of them chemically reactive, see for example Finlayson-Pitts and Pitts (2000) and Graedel et al. (1986), which is subject to solar photons, absorbs and emits infrared photons, experiences temperatures ranging from −100 to 40° C, is exposed to the ocean, encompasses phase changes of water and sustains turbulent flow, it involves significant parts of physical chemistry. Pedagogically, the three-volume set by Berry, Rice, and Ross (2002a, b, c) covers the basic physicochemical material clearly and thoroughly, particularly Chapters 19, 20, 27, 28, 30, and 31. In addition to kinetic molecular theory, chemical kinetics, spectroscopy, and equilibrium statistical mechanics, there are other branches of physical science which are applicable to the atmosphere; in our context they include of course meteorology and turbulence theory. It ought to be recognized that the atmosphere has high complexity arising from a vast number of degrees of freedom, several anisotropies, and morphologically complicated boundaries extending over 15 orders of magnitude in scale from the molecular mean free path to the Earth’s circumference; these factors and the concomitant non-linearities make the application of non-equilibrium statistical mechanics a daunting prospect, but nevertheless one which should be attempted, for the reason that the energy distributions and their transformations in the atmosphere need to be accurately described, particularly in the representation and prognosis of the climatic state. We will also show that vorticity is the fundamental variable, since vortices are generated from molecular populations subjected to an anisotropy, on very short space scales and fast time scales. In this Chapter we will give a skeletal survey connecting these basic subjects, with references to more comprehensive, individual sources. The simplest possible molecular model for a gas is a collection of spherical ‘billiard balls’—the intermolecular potential consists of an infinite repulsive force on contact. This approach, pioneered by Waterston, Maxwell, and Boltzmann, is successful for air as a first approximation. The idea is that collisions are completely elastic, with no interaction between potential collidant molecules until physical contact occurs, whereupon an infinite repulsive potential operates.

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"maize, 1.4-2.7%; of waxy barley, 2.1-8.3%; and of waxy swell only slightly in cold water. Granules differ in size rice 0-2.3%; thus the range of amylose contents of the and shape among plants. For example, corn starch has an waxy wheats is comparable to that of other waxy cereal average diameter of about 15 1.1,M, wheat starch has a bi-grains. Biochemical features of starch from waxy wheats modal size distribution of 25-40 and 5-10 [tm, potato are similar to those of waxy maize [71]. starch has an average size of 40 WTI, and rice starch has an Starch from barley contains 22-26% amylose, the rest average size of 5µm [99]. being amylopectin [28]. However, samples of 11-26% The particle sizes of starch granules have recently re-amylose are known, and starch from waxy barley contains ceived much attention because of their important roles in only 0-3% amylose, while high-amylose starches contain determining both the taste and mouthfeel of fat substitutes up to 45%. and the tensible properties of degradable plastic films. Amylose content of rice is categorized as very low Daniel and Whistler [39] reported that small-granule (0-9%), low (9-20%), intermediate (20-25%), or high starch about 2 !um in diameter, or similar in size to the lipid (25-33%) [124]. The amylose content of long grain rice micelle, had advantages as a fat substitute. Lim et al. [117] ranges from 23 to 26%, while medium grain ranges from investigated the use of starches of different particle size in 15 to 20% and short grain ranges from 18 to 20% [103]. degradable plastic film. They reported that a linear correla-Oat amylose content (16-27%) is similar to that of tion between film thickness and particle size and an in-wheat starch, but oat amylose is more linear and oat amy-verse linear correlation between film thickness and particle lopectin is more branched than that found in wheat [121]. size. Small-granule starches may also be used as face pow-Most sorghum starch is similar in composition to corn der or dusting powder, as a stabilizer in baking powder, and contains 70-80% branched amylopectin and 21-28% and as laundry-stiffening agents. amylose [127]. However, waxy or glutinous sorghum con-The size of the wheat starch granule is 1-30 lam, the tains starch with 100% amylopectin and has unique prop-size distribution being bimodal. Such a bimodal size distri-erties similar to waxy corn [158]. Badi et al. [11] reported bution is characteristic of wheat starch, as well as of rye 17% amylose in starch from one pearl milled population. and barley starches. Wheat starch consists of two basic Gracza [69] reviewed the minor constituents of starch. forms: small spherical granules (about 5-10 wri) and larg-Cereal starches contain low levels of lipids. Usually, the er lenticular granules (about 25-4011m). The small B-gran-lipids associated with starch are polar lipids. Generally, the ules are spherical and have a diameter of less than 10 wrt; level of lipids in cereal starch is between 0.5 and 1%. Be-a mean value of about 4 lam has been reported. The large sides low levels of other minerals, starches contain phos-A-granules are lenticular and have a diameter greater than phorus and nitrogen. In the cereals, phosphorus occurs 10 lam, with a mean 14.11.1m. In reality, the granules have a mostly in the form of phospholipids. The nitrogen is gener-continuous distribution of granule size within the range ally considered to be present as protein, but it may also be designated for that starch. Amylose and amylopectin are a constituent of the lipid fraction. intermixed and distributed evenly throughout the granule. The interaction between amylose and lipids is more Many believe that the composition and properties of small powerful by far than that between amylopectin and lipids and large granules are similar, but this is a subject of some [55]. It is well established that polar lipids (e.g., mono-argument and the subject of many research studies [42]. glycerides, fatty acids, and similar compounds) form a hel-Kulp [110] evaluated the fundamental and bread-mak-ical inclusion complex with the amylose molecule, be-ing properties of small wheat starch granules and com-tween the hydrocarbon chain of the lipid and the interior of pared them with those of regular starch. Small granules the amylose helix. were found to be lower in iodine affinity, indicating differ-ences in amylose levels or some fundamental structural differences. Gelatinization temperature ranges, water-binding capacities, and enzymic susceptibilities of small Starch is laid down in the shape of particles in special amy-granules were higher than those of regular ones. loplast cells in the plant. These particles are called gran-Rice has one of the smallest starch granules of cereal ules, and they are the means by which the plant stores en-grains, ranging in size from 3 to 5 pm in the mature grain, ergy for the carbohydrate in a space-saving way, but also to although the small granules of wheat starch are almost the make the energy easily accessible when the seed germi-same size [33]. The small granule size of that starch results nates [57]. One starch granule is synthesized in each amy-in physical properties that make it useful as a dusting flour loplast, and the shape and size of a starch granule is typical in bakeries. Rice starch amyloses have degree of polymer-of its botanical origin. ization (DP) values of 1000-1100 and average chain Starch granules are relatively dense, insoluble, and lengths of 250-320. These structural properties of amylose." In Handbook of Cereal Science and Technology, Revised and Expanded, 405–32. CRC Press, 2000. http://dx.doi.org/10.1201/9781420027228-41.

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Conference papers on the topic "Spherical Population"

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Zhong, Lin, Sichen Tao, Qingya Sui, Haichuan Yang, Zhenyu Lei, and Shangce Gao. "A Population Resource Allocation-based Adaptive Spherical Search Algorithm." In 2022 IEEE International Conference on Networking, Sensing and Control (ICNSC). IEEE, 2022. http://dx.doi.org/10.1109/icnsc55942.2022.10004116.

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Baudart, T. "PAL performance analysis for torical prescription." In Vision Science and its Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/vsia.1996.sua.3.

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Progressive-Addition Lenses (PAL) are commonly designed for non-astigmatic lens wearers, yet a large proportion of the population requires toric correction. Moreover, the optical performances of PAL are always given for lenses with spherical prescription. In fact, the charts of optical performances for PAL with toric prescription are not easy to interpret because of the combination of astigmatism induced by the progressive surface, the toric surface, and the obliquity of light rays.

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Sassen, Kenneth. "A Cirrus Cloud Glory." In Light and Color in the Open Air. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/lcoa.1997.lwa.2.

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On 20 January 1995, an apparent cirrus cloud glory was photographed over central Utah from an airline passing through the 10.7 km MSL level as it began its descent into Salt Lake City International Airport. The cirrus cloud layer was geographically widespread and optically thin enough to view the snow-covered Wasatch Mountain Plateau beneath the cloud. The glory was easily visible surrounding the shadow of the aircraft, ahead of a short contrail. Photographic analysis shows a single reddish-brown ring of ~2.1° radius surrounding a central bright spot, although a vague second ring appeared visually to have been present over the brief (~3-min) observation period. The presence of a glory can only be accounted for through the interference effects of the backscattered light rays for particles that are spherical in shape. Coincident Salt Lake City radiosonde data show a cirrus cloud top temperature in the -50° to -55°C range. We are unable to evoke the presence of other, more exotic cloud forming substances at the indicated cloud temperature to explain this phenomenon. Hence, employing Mie theory scattering simulations, we conclude that this apparently unique atmospheric optical observation provides evidence for the occurrence of a population of ~20 μm diameter spherical ice particles. This size is consistent with those derived from cirrus cloud top corona displays, although in such cases unusually high linear depolarization ratios suggest the presence of complicated particle shapes. The lack of vivid colorization in the glory implies that the particle size distribution may have been broader than those of typical cloud droplet populations producing glories, or that the ice spheres were somewhat irregular in surface complexity. The brief appearance of this cirrus cloud glory, and its location over mountainous terrain, suggests that the cloud generating mechanism was a mountain wave cloud at about the cirrus cloud top position.

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Kotzalas, Michael N. "Statistical Distribution of Tapered Roller Bearing Fatigue Lives at High Levels of Reliability." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63052.

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The original two-parameter Weibull distribution used for rolling element bearing fatigue tends to greatly underestimate life at high levels of reliability. This fact has been proven for through hardened ball, cylindrical and spherical roller bearings, as well as linear ball bearings, by other researchers. However, to date this has not been done with tapered roller bearings (TRB) or case carburized materials, and as such this study was conducted. First, the three-parameter Weibull distribution was utilized to create a mathematical model, and statistical data analysis methods were put into place. This algorithm was then investigated as to its ability to discern the shape of the reliability distribution using known, numerically generated, data sets for two and three-parameter Weibull distributions. After validation, an experimental data set of 9702 TRB’s, 98% of which were case carburized, was collected. Using the developed algorithm on this data set, the overall RMS error was reduced from 26.0% for the standard, two-parameter to 12.2% for the three-parameter Wiebull distribution. Also, the error at 99.9% reliability was reduced from 95.8% to 37%. However, as the results within varied from previously published values at high reliabilities, there is likely a difference in the underlying population and/or dependency on the statistical and mathematical methods utilized. Therefore, more investigation should be conducted in this area to identify the underlying variables and their effects on the results.

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Lugiato, Luigi A., Lorenzo M. Narducci, Jorge R. Tredicce, and Donna K. Bandy. "Effect of a transverse beam profile on the dynamics of a homogeneously broadened ring laser." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.mf8.

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Most theoretical treatments of laser dynamics have been based on the plane wave approximation for the cavity field. They have also led, for the most part, to seemingly incorrect predictions for 'the instability thresholds. In an attempt to characterize the role played by the transverse intensity and phase variations of the cavity field, we have generalized the usual Maxwell-Bloch equations to include several common features that are present in experimental laser systems. We consider a unidirectional ring laser with a resonator containing spherical mirrors of arbitrary reflectivity and radius of curvature. We assume the active medium to behave as a collection of homogeneously broadened two-level systems with a transverse variation of inversion, as is normally found in typical discharge-excited systems, and we simulate the presence of a confining plasma tube with a fictitious transverse linear absorption profile, which is essentially zero everywhere except in the vicinity of the container walls. Our numerical search for the steady-state field distribution inside the cavity shows that well-behaved steady-state solutions may develop an unstable character for gain values that are not significantly higher than the ordinary laser threshold. These low threshold instabilities seem to arise as a result of a large enough mismatch between the transverse profile of the empty resonator field and of the population inversion. Bistability at threshold also seems to be part of the observed phenomenology.

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Zheng, Ying, and Wilson S. Meng. "Polycation Coated Polymeric Particles as Vehicles of RNA Delivery Into Immune Cells." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3714.

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The purpose of this work is to develop a carrier system for delivering RNA molecules aimed to downregulate specific functions in T cells. In many forms of cancer, T cells that express the protein Forkhead Box P3 (Foxp3) are associated with cancer progression. These cells can be identified by CD4 and CD25, molecules express on the cell surface. Studies have shown that downregulation of Foxp3 can increase the ability of other immune cells to destroy tumors. A class of RNA molecules, commonly referred to as “siRNA”, bind to and degrade specific messenger RNA (mRNA) in a sequence-dependent manner such that expression of the encoded protein is terminated. Because mRNA molecules are located inside cells, a carrier system is required to facilitate the uptake of siRNA, which does not passively diffuse through the plasma membrane. To this end, nanosized polymeric particles coated with the polycation, ornithinex10-histidinex6 (or O10H6) were used to adsorb siRNA that bind to the mRNA encoding Foxp3. The RNA-loaded particles are spherical and uniform in size (normally distributed, polydispersity index = 0.072). Loading of RNA to the particles was confirmed using gel electrophoresis. RNA complexed with the particles are protected from serum destabilization: 83.1% of RNA were recovered compared to 36.1% in RNA that were not associated with the particles. Association with the particles increased the uptake of the RNA in mouse T cells from 3.2±0.2% (free RNA) to 20.1±3.9%. Specifically, uptake of the RNA in T cells that express CD4 increased from 2.7±0.2% to 27.1±1.3% when particles were employed. These differences are statistically significant in three experiments conducted (p < 0.01). Internalization of the RNA into T cells was confirmed using confocal imaging. Flow cytometric analysis showed that the particle-complexed RNA reduced the percentage of T cells that express both CD4 and CD25 in mice carrying tumors from 24.0% when free RNA molecules were used to 13.5%. In these cells, the level of Foxp3 mRNA was reduced by 30%. In conclusion, the particles facilitate the uptake of siRNA molecules into a population of T cells that is known to promote cancer growth.

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Starc, Vito, and Cees A. Swenne. "Spatial Distribution and Orientation of a Single Moving Dipole Computed in 12-Lead ECGs in a Healthy Population Using a Spherically Bounded Model." In 2017 Computing in Cardiology Conference. Computing in Cardiology, 2017. http://dx.doi.org/10.22489/cinc.2017.242-277.

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Rosenthal, S. J., A. T. Yeh, A. P. Alivisatos, and C. V. Shank. "Size Dependent Absorption Anisotropy Measurements of CdSe Nanocrystals: Symmetry Assignments for the Lowest Exciton State." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.45.

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Semiconducting nanocrystals smaller in size than the bulk Bohr exciton display quantum confinement, leading to a size dependent energy gap and concentration of oscillator strength into a few transitions. Given these properties these materials are being investigated for potential device applications. CdSe nanocrystals have already been implemented in tunable light emitting diodes.1 We have performed absorption anisotropy experiments on CdSe crystals ranging in diameter from 30-50A with the goal of elucidating the symmetry of the lowest energy optical transition and the earliest events of carrier evolution. The optical anisotropy is defined as R(t)=I‖ (t)-I⊥ (t)/K(t), where K(t) is the total population decay (I‖ + 2I⊥). The initial value of the anisotropy, R(0), is indicative of the nature of the optical transition. For example, if the transition is spherically degenerate, as for C60, R(0) is expected to be 0.0. A linear dipole transition has R(0)=0.4 and for a degenerate planar transition R(0)=0.15.2 The decay in the anisotropy may contain contributions from rotational diffusion, rotation of the transition dipole, as in an isomerization reaction, or population transfer between two excited state levels with transition dipoles of different directions. High time resolution measurements performed on nanocrystals thus give us insight into the shape of the optical transition and the earliest dynamics of the excited carriers. We’ve discovered that a competition exists between the intrinsic wurtzite crystal field and the nonspherical confinement in the crystal3 which dictates the symmetry of the first exciton state. The crystals are thus intrinsically dichroic, a phenomenon which may be exploited in device applications.

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Mueller, Stephen. "Designing for Irradiated Shade." In 2020 ACSA Fall Conference. ACSA Press, 2020. http://dx.doi.org/10.35483/acsa.aia.fallintercarbon.20.29.

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Irradiated Shade is an ongoing project that develops a means of uncovering, representing, and designing for the unseen dangers of ultraviolet radiation within conditions of apparent shade—a growing yet under-explored threat to cities, buildings, and bodies. The project leverages its position in the US-Mexico borderlands, a vital testing ground in which physiological effects of solar radiation are rendered upon vulnerable populations. This paper will discuss: the design context, considerations for ultraviolet (UV) radiation as a complex design problem, the limits of existing design tools to address conditions of UV at a building scale, and the development of custom architectural design tools to improve the ability to visualize and combat UV exposure. The paper introduces an algorithmic drawing technique capable of mapping the built environment from the perspective of UVB scatter, producing spherically-projected sky dome maps indicating the risk of UVB exposure in a particular location to sensitize designers to this hidden danger.

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Tong, F., R. M. Macfarlane, and W. Lenth. "Cascade lasing at 730 and 1053 nm in LiYF4:Nd using upconversion pumping." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tuo3.

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We recently reported the observation of upconversion laser action in LiYF4:Nd3+ at 729.6 and 413.0 nm originating from the 2P3/2 level at 26,258 cm–1.1 Here we report on cascade laser action at 729.6 and 1053.0 nm using upconversion pumping with a yellow dye laser at low temperatures (T < 70 K). The upconversion excitation of the 2P3/2 level exhibits an unusual nonlinear dependence on pump power and a delayed buildup time.1 The 2-mm long laser crystal of LiYF4:Nd3+ (1%) had spherically polished faces on which mirror coatings were directly deposited. The mirror reflectivities were high (>98%) at 730 nm and low (~15%) at 1053 nm. When pumped by a 603.6-nm cw dye laser oscillation was observed at 729.6 nm, corresponding to the 2P3/2(1) → (4f5/2, 2H9/2)(3) transition. The ions quickly relax nonradiatively to the 4F3/2 state whose lifetime is 525 µs. The resulting buildup in population brings the 1053.0-nm laser transition [4F3/2(1) → 4F11/2(2)] above threshold. At 20 K the pump threshold for cascade laser operation was obtained with 40 mW of incident dye laser power. Investigations of the laser dynamics showed that the 1053.0-nm laser reaches its threshold ~300 µs after the onset of 729.6-nm laser.

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Reports on the topic "Spherical Population"

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Robertson, A., F. Hemez, I. Salazar, and T. Duffey. Modal Testing Repeatability of a Population of Spherical Shells. Office of Scientific and Technical Information (OSTI), May 2004. http://dx.doi.org/10.2172/828954.

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