Top PDF H, He-like recombination spectra I : l-changing collisions for hydrogen

H, He-like recombination spectra I : l-changing collisions for hydrogen

H, He-like recombination spectra I : l-changing collisions for hydrogen

Hydrogen and helium emission lines in nebulae form by radiative recombination. This is a simple process which, in principle, can be described to very high precision. Ratios of He I and H I emission lines can be used to measure the He + /H + abundance ratio to the same precision as the recombination rate coefficients. This paper investigates the controversy over the correct theory to describe dipole l-changing collisions (nl → nl 0 = l ± 1) between energy-degenerate states within an n-shell. The work of Pengelly & Seaton (1964) has, for half-a-century, been considered the definitive study which “solved” the problem. Recent work by Vrinceanu et al. (2012) recommended the use of rate coefficients from a semi-classical approximation which are nearly an order of magnitude smaller than those of Pengelly & Seaton (1964), with the result that significantly higher densities are needed for the nl populations to come into local thermodynamic equilibrium.
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H-, He-like recombination spectra III. n-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination lines

H-, He-like recombination spectra III. n-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination lines

temperature to the continuum brightness temperature (Rohlfs & Wilson 2000). However, non-LTE effects can be important for RRL (Brown, Lockman & Knapp 1978). Likewise, stimulated emission (maser effects) and pressure broadening effects can alter the equilibrium of lines (Shaver 1980). In these cases, modelling of the level populations using collisional radiative (CR) modelling (Dupree & Goldberg 1970; Brocklehurst & Seaton 1972; Burgess & Summers 1976) is needed to obtain the correct line intensities. CR modelling is subject to the availability and accuracy of the fundamental atomic data describing the processes between the different particles of the emitting gas. The highest uncertainties come from the collisional (de-)excitation, which can be divided into two types of interaction: energy changing and angular momentum changing. In the previous two papers of this series, devoted to investigate and assess these collisional data, which have a high impact on astronomical observations (Guzm´an et al. 2016, 2017, hereafter Paper I and Paper II), we showed how the disparities in the theoretical values of l-changing collisions cross-sections can affect the emissivities of the optical recombination lines. l-changing collisions are mainly produced by ion impact and alter the angular
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H, He-like recombination spectra - II ι-changing collisions for He Rydberg states

H, He-like recombination spectra - II ι-changing collisions for He Rydberg states

low-l subshells are not energy degenerate. A criterion for deciding when the energy separation between l subshells is small enough to apply energy-degenerate collisional theories is given. Moreover, for certain conditions, the Bethe approximation originally proposed by Pengelly & Seaton is not sufficiently accurate. We introduce a simple modification of this theory which leads to rate coefficients which agree well with those obtained from pure quantal calculations using the approach of Vrinceanu et al. We show that the l-changing rate coefficients from the different theoretical approaches lead to differences of ∼10 per cent in He I emissivities in
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H i di ngD a t a i n aQ I m a g eF i l e

H i di ngD a t a i n aQ I m a g eF i l e

The procedure of hiding a message inside an image made of qutrits is based on the entanglement of the states of three qubits: the first one belongs to the image, the sec- ond one belongs to the secret key, and the third one be- longs to the message itself. Andrzej Grudka and Antoni Wjcik [2] showed that from a qutrit can be reconstructed a qubit with a state randomly chosen. A qubit is repre- sented in an orthogonal base {|ii,|j i}, thus:

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Ho u s i n g Po l i c y Is Sc h o o l Po l i c y :

Ho u s i n g Po l i c y Is Sc h o o l Po l i c y :

28, no. 3 (2008.): 451–71. For ethnographic studies about high poverty school environ- ments, see Judith M. Parr and Michael A. R. Townsend, “Environments, Processes, and Mechanisms in Peer Learning,” International Journal of Educational Research 37 (2002): 403–23; Martin Thrupp, “A Decade of Reform in New Zealand Education: Where to Now? Introduction,” New Zealand Journal of Educational Studies 34, no. 1 (1999): 5–7; Martin Thrupp, “Education Policy and Social Change,” British Journal of Sociology of Education 23, no. 2 (2002): 321–32. For studies about parental interactions with schools, see Annette Lareau and Erin M. Horvat, “Moments of Social Inclusion and Exclusion: Race, Class, and Social Capital in Family-School Relationships,” Sociology of Education 72, no. 1 (1999): 37–53; Erin M. Horvat, Elliot B. Weininger, and Annette Lareau, “From Social Ties to Social Capital: Class Differences in the Relations between Schools and Parent Networks,” American Educational Research Journal 40, no. 2 (2003): 319–51. For studies about teacher expectations and student- teacher interactions, see Annette Lareau, “Social Class Differences in Family-School Relationships: The Importance of Cultural Capital,” Sociology of Education 60, no. 2 (1987): 73–85; Susan Lasky, “The Cultural and Emotional Politics of Teacher-Parent Interactions,” Teaching and Teacher Education 16, no. 8 (2000): 843–60; P. Penny Hauser-Cram, Selcuk R. Sirin, and Deborah Stipek, “When Teachers’ and Parents’ Values Differ: Teachers’ Ratings of Academic Competence in Children from Low- income Families,” Journal of Educational Psychology 95, no. 4 (2003): 813–20; Ian A. G. Wilkinson, “Introduction: Peer Influences on Learning: Where Are They?” International Journal of Educational Research 37 (2002): 395–401; Matthew L. Pittinsky, “Smart by (Perceived) Association: Cognitive Social Networks and Teacher Academic Judgments,” PhD dissertation, Columbia University, 2008; and Barbara F. Chorzempa and Steven Graham, “Primary-grade Teachers’ Use of Within-class Ability Grouping in Reading,” Journal of Educational Psychology 98, no. 3 (2006.): 529–41. 12. Frederick M. Hess, Spinning Wheels: The Politics of Urban School Reform (Washington, D.C.: Brookings Institution Press, 1999).
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C I T Y O F B E V E R L Y H I L L S

C I T Y O F B E V E R L Y H I L L S

Sustainability is often described as the intersection of environmental sensitivity, economic soundness and social equity. It is generally understood that in order for policies, programs[r]

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C h r i s t o p h e D e l v a l l é Music of the soul

C h r i s t o p h e D e l v a l l é Music of the soul

I am touched by your universe, which is multifold and generous. I like your sensitivity and the many touches of the heart and of the ear. :) We’re transported from great French classicism with notes of Satie, Debussy, latino/tango, nostalgia, elegance, harmonic colors, to contemporary and atonal music and to a more jazzy universe. I can’t help thinking of the grand masters of the genre.

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L I FT I NG P R O B L E M S AND T HE I R I ND E P E ND E NC EO F T HE C O E FFI C I E NT FI E L D

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First I want to thank whoever was in the admission committee five years ago and decided to give me the chance to live the life of a graduate student at Penn. When I got here, it wasn’t the thought of graduating some day that was driving me, but I just wanted to experience graduate school, and (mostly) it has been what I hoped it would. I have been able to do the work I enjoy in a great environment: I have College green as my backyard, Houston hall as my living room, and the library as my study room.

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E N G L I S H RENT ALLOWANCE

E N G L I S H RENT ALLOWANCE

To find out if rent allowance is possible for your income you can enter your personal details and the subsidiable portion of the rent at www.toeslagen.nl, the website of the ‘Belastingdienst’. For more info please call the Dutch Tax office 0800 - 0543. Unfortunately the Dutch Tax office does only answer phone calls in Dutch. In this text we’d like to inform you about the rent allowance, and ‘How to’ apply for rent allowance.

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C O N WAY L A K E S H E A LT H & R E H A B I L I TAT I O N C E N T E R

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Handicap access, including number of spaces, entrance pathways, ramps, etc., shall be provided as required by and in accordance with the Federal ADA (Americans with Disabilities Act) St[r]

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I D C T E C H N O L O G Y S P O T L I G H T

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NetApp SnapProtect backup management application and AltaVault cloud-integrated storage provide the combination of backup management and purpose-built cloud-integrated storage appliance[r]

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Orbital Dynamics in 3 He-A *l

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As a result the motion of d-vector becomes relaxation not oscillation which is derived theoretical- ly9l.Iol and observed experimentally.w In calculation of the dyn[r]

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I N T E R N A T I O N E L L A H A N D E L S H Ö G S K O L A N HÖGSKOLAN I JÖNKÖPING. The Case of China

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Regression analysis is used to show the empirical findings for this thesis. The econometric model is based on cross-sectional data for the Chinese regions over a time period from 1994 to 2003. The reason that 1994 is chosen as a staring year is that China was still under a planned regime in the pre- 1994 period, characterized by rigorous foreign exchange con- trol regulations. Because of the lack of accurate statistical data after 2003, that is the end year of the analysis. I have divided the time period 1994-2003 into two time periods of five years. The first one includes the years 1994-1998. The reason for the division of the two time periods is that in 1999, the Asian financial crisis was over and most Asian economies had started to recover. I expect to see a positive relationship between the level of GDP and FDI and that the increase in FDI has a significant impact on the increase in GDP. The data is collected from the National Bureau of Statistics China through the China Statistical Yearbook.
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A M H E R S T P U B L I C S C H O O L S A M H E R S T R E G I O N A L M I D D L E S C H O O L A F T E R - S C H O O L C L U B S

Do you like to play rock n' roll? We like to play rock n' roll! The Rock n' Roll Club is a musical club that meets weekly to practice and perform music. We select songs that seem like they would be fun to play, learn them, and rock out! Last year, some of the songs we worked on included "Crazy Train" by Ozzy Osborne, "Seven Nation Army" by the White Stripes, and "Sweet Child O' Mine" by Guns n' Roses. We are excited for another year of rock!

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A theoretical investigation of low energy proton on hydrogen collisions

A theoretical investigation of low energy proton on hydrogen collisions

energy, moderate to large scattering angle region, a method is required which solves for both the nuclear motion and the electronic wavefunction without any constant potential approximat[r]

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It s Like This. Venerable Ajahn Chah. Translated from the Thai by Thanissaro Bhikkhu D H A M M A S I M I L E S

It s Like This. Venerable Ajahn Chah. Translated from the Thai by Thanissaro Bhikkhu D H A M M A S I M I L E S

When you go for alms in the village, put on your robes neatly before you go. Exercise restraint as you go for alms. I’ve seen new monks and novices who don’t know anything. When they eat in someone’s house, they have to look around, all over the place. Why do they have to look around? Some of them even stare—it’s even worse than lay people. It’s because they’ve been living in the wilderness and haven’t seen anything like this for a long while. When they go into someone’s home, they see this, see that, and it pulls at their eyes. They look all around because they’re hungry. It’s kind of like a dog: When it stays in the village market, it doesn’t bark very much. But if you take it out into the wilderness and the wind blows the leaves around, it barks all night.
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h o t e l m i n i b a r s

h o t e l m i n i b a r s

MoDel b15 b25 s30 s40 b50 b60 VoluMe 15 litres 25 litres 30 litres 40 litres 50 litres 60 litres DiMension h/w/D mm 455x350x305 455x350x385 500x400x410 560x400x430 670x402x455 605x460x480 enerGy consuMPtion* 0.75 kwh/24h 0.75 kwh/24h 0.75 kwh/24h 0.85 kwh/24h 1.05 kwh/24h 1.10 kwh/24h Door oPeninG reversible reversible reversible reversible reversible reversible VoltaGe 220-240V 220-240V 220-240V 220-240V 220-240V 220-240V

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T E C H N I C A L M A N U A L

T E C H N I C A L M A N U A L

Cylinders for Door Hardware locks are only available as an American Lock ® EDGE ™ product and have a standard size shell for a mortise, rim and KIK.. application.[r]

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