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Narayanasamy, Sumithira. "Visual demands of modern primary classrooms and the impact of refractive anomalies on academic performance." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/84876/9/Sumithira_Narayanasamy_Thesis.pdf.
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This research investigated the visual demands in modern primary school classrooms and also the impact of common refractive anomalies on a child's ability to perform academic-related tasks. The results showed that relatively high levels of visual acuity, contrast demand and sustained accommodative-convergence are required to perform optimally in the modern classroom environment. It was also demonstrated that relatively low magnitudes of uncorrected refractive error may have a detrimental impact on children's ability to perform academic-related activities at school, with sustained near work further exacerbating this effect. These findings have important implications for both eye care practitioners and education authorities.
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Intert, Elisa-Marie [Verfasser], and Toam [Akademischer Betreuer] Katz. "Wirksamkeit, Vorhersagbarkeit und Sicherheit einer erneuten Behandlung nach hyperoper Laser in situ keratomileusis - spielt die verborgene Hyperopie eine Rolle? / Elisa-Marie Intert ; Betreuer: Toam Katz." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2019. http://d-nb.info/1186891807/34.
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Huang, Shufeng. "A HyperNet Architecture." UKnowledge, 2014. http://uknowledge.uky.edu/cs_etds/18.
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Network virtualization is becoming a fundamental building block of future Internet architectures. By adding networking resources into the “cloud”, it is possible for users to rent virtual routers from the underlying network infrastructure, connect them with virtual channels to form a virtual network, and tailor the virtual network (e.g., load application-specific networking protocols, libraries and software stacks on to the virtual routers) to carry out a specific task. In addition, network virtualization technology allows such special-purpose virtual networks to co-exist on the same set of network infrastructure without interfering with each other.
Although the underlying network resources needed to support virtualized networks are rapidly becoming available, constructing a virtual network from the ground up and using the network is a challenging and labor-intensive task, one best left to experts.
To tackle this problem, we introduce the concept of a HyperNet, a pre-built, pre-configured network package that a user can easily deploy or access a virtual network to carry out a specific task (e.g., multicast video conferencing). HyperNets package together the network topology configuration, software, and network services needed to create and deploy a custom virtual network. Users download HyperNets from HyperNet repositories and then “run” them on virtualized network infrastructure much like users download and run virtual appliances on a virtual machine. To support the HyperNet abstraction, we created a Network Hypervisor service that provides a set of APIs that can be called to create a virtual network with certain characteristics.
To evaluate the HyperNet architecture, we implemented several example Hyper-Nets and ran them on our prototype implementation of the Network Hypervisor. Our experiments show that the Hypervisor API can be used to compose almost any special-purpose network – networks capable of carrying out functions that the current Internet does not provide. Moreover, the design of our HyperNet architecture is highly extensible, enabling developers to write high-level libraries (using the Network Hypervisor APIs) to achieve complicated tasks.
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Newbold, David Michael. "Inclusive hyperon polarisation studies at the CERN SPS hyperon beam." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265386.
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De, Bie Ellinor. "Prevalensen av hyperopi och astigmatism hos barn med ospecifika läs- och skrivsvårigheter respektive barn med dyslexi." Thesis, Linnéuniversitetet, Institutionen för medicin och optometri (MEO), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-36016.
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Syfte:Målet med studien var att undersöka om prevalensen av hyperopi (och inducerad hyperopi) och astigmatism skiljer sig mellan barn med dyslexi och barn med ospecifika läs- och skrivsvårigheter. Blir de hjälpta av eventuell korrektion? Metod:Skolpedagoger i Kalmar, Nybro och Mörbylånga lämnade ut inbjudan för synundersökning till barn med läs-och skrivsvårigheter.Synundersökninanra genomfördes på C-optik synklinik i Kalmar.Tjugofyra barn med ospecefika läs- och skrivsvårigheter och nio barn med dyslexi deltog i undersökningen . En tid efter synundersökningen kontaktades förädrar för en uppföljningsintervju. Resultat: Jämförelse mellan grupperna visade ingen skillnad med avseende refraktion. Alla barn som deltog förutom ett, ordinerades korrektion för hyperopi. Ett barn var myopt med inducerad hyperopi. Samtliga barn förutom ett ordinerades korrektion för astigmatism. Efter en tid gjorde ett uppföljnings samtal till föräldrarna. Alla barn förutom ett använde sina glasögon. Många av barnen hade fått minskade besvär som var relaterade till okorrigerade synfel.
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Backrot, Therése. "Prevalensen av refraktionsfel bland hjälpsökande i Guatemala." Thesis, Linnéuniversitetet, Institutionen för medicin och optometri (MEO), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-35375.
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Bakgrund: Ametropi, som även kallas refraktionsfel, är vanligt förekommande runt om i världen och många människor är i behov av att bli korrigerade med hjälp av glasögon. Ametropi delas in i tre kategorier myopi, hyperopi och astigmatism. Syfte: Syftet med den här studien är att under en resa med hjälporganisationen Vision for All (VFA) till Guatemala undersöka prevalensen av refraktionsfel bland de hjälpsökande och jämföra resultatet med tidigare prevalensstudier från andra delar av världen. Material och metod: Studien genomfördes i april 2014 under en resa med Vision for All till Guatemala. Under resan besöktes sju orter, tre orter runt staden Antigua Guatemala och fyra orter i regionen Petén. Befolkningen sökte självmant till undersökningsstationerna där synscreening utfördes med hjälp av flipprar, provlådor, provbågar och syntavlor med optotyper och Snellen E-hake. Undersökningarna utfördes av sex optikerstudenter och en legitimerad optiker. Glasögon delades ut till de hjälpsökande som var i behov av korrektion av tre optikerassistenter. Resultaten från samtliga undersökningar journalfördes och jämfördes med resultat från tidigare prevalensstudier från andra delar av världen. Resultat: I studien ingår 1 171 hjälpsökande i åldrarna 6–92 år. Definitionen av myopi är i den här studien SE ≤ -0,50 D och hyperopi SE ≥ +0,50 D. De gränserna valdes för att det oftast är de definitionerna som använts i tidigare studier. Prevalensen av myopi bland de hjälpsökande var i den här studien 15 % och hyperopi var 39 %. I orterna runt Antigua Guatemala undersöktes 344 personer, 30 % var myopa och 19 % hyperopa. I regionen Petén undersöktes 827 personer, 9 % var myopa och 47 % hyperopa. Studien visade att det inte var någon signifikant skillnad på prevalensen av refraktionsfel mellan män och kvinnor. Slutsats: Resultatet från den här studien visar att prevalensen av hyperopi är högre än prevalensen av myopi i Guatemala. Samma resultat kan ses i tidigare studier från Nigeria och Mongoliet. Studier från USA och större delen av Europa visar på motsatsen, prevalensen av myopi är högre än prevalensen av hyperopi.
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Noble, Anthony James. "A measurement of the branching ratio for the weak radiative decay of the lambda hyperon." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/31075.
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In a measurement performed at the Brookhaven National Laboratory we have measured
the branching ratio for the weak radiative decay of the ∧ hyperon. Our result,
[formula omitted] is the second, but most precise, measurement of this quantity. It is in slight disagreement
with the earlier measurement.
Using a thick copper degrader, kaons of initial momentum 680 MeV/c were brought to rest in a liquid hydrogen target. Absorption of these kaons on target protons produced a ∧, either directly via the reaction K⁻p —> ∧ + π⁰, or indirectly via the reaction K⁻p —> Ʃ° + π° with subsequent decay, Ʃ° —> ∧ + [formula omitted]. The occurrence of each of these processes was established by observing the π° decay photons in a modular NaI detector, the Crystal Box. This detector was used to measure the energy and position of the final state particles, and hence allowed the topology of the event to be reconstructed.
A wide range of theoretical techniques have been employed to estimate hyperon
weak radiative decay amplitudes, including pole models, symmetry arguments,
PCAC, and direct quark level calculations. These calculations must combine facets of the strong, weak and electromagnetic interactions. Hence, hyperon decays provide a testing ground for theorists to measure their ability to bring together these components in a relatively simple system. We discuss the implications of our result for a representative selection of theoretical estimates.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Wogatai, Ulrika. "Förekomst av hyperopi bland hjälpsökande på en VFA-resa i Bolivia." Thesis, Linnaeus University, School of Natural Sciences, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-6076.
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Syfte: Att undersöka förekomst av hyperopi i förhållande till läskunnighet hos hjälpsökande hos VFA i Bolivia, samt jämföra med studier från andra delar av världen.
Metod: Studien utfördes i april 2010 på tre olika orter i centrala Bolivia. Patienterna sökte själva upp platsen för att få en undersökning. Subjektiv refraktion utfördes binokulärt, utan dimning, med hjälp av provbåge, provlåda och syntavla med Snellen E, uppsatt på 5 meters avstånd. Hyperopi räknades som sfärisk ekvivalent ≥ +1,00 D, myopi som ≤ –0,25 DS.
Resultat: 1 313 personer undersöktes, varav 1 271, mellan 6 och 92 år gamla, ingick i studien. Förekomsten av hyperopi var totalt 23,8% (som mest 39,8% hos kvinnor 66-92 år gamla, och som minst 10,7% hos kvinnor 6-19 år gamla), läskunnighet totalt var 81,7% (kvinnor 74,7%, män 90,7%). Det var något lägre läskunnighet bland hyperoper (78,1%) än bland myoper (83,2%) och emmetroper (82,7%).
Slutsats: Bolivia verkar ha större förekomst av hyperopi än Asien och Europa. Hyperopi ökar med åldern, främst efter 50-årsåldern. Miljöfaktorn ser ut att ha viss betydelse.
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Finnman, Louise. "Förekomsten av refraktionsfel hos befolkningen mellan 10-35 år i Guatemala." Thesis, Linnéuniversitetet, Institutionen för medicin och optometri (MEO), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-53889.
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Syfte: Syftet med studien var att undersöka förekomsten av hyperopi och myopi hos personer mellan 10-35 år i Guatemala. Samt att undersöka förekomsten av refraktionsfel bland olika yrkesgrupper. Material och metod: Studien utfördes från den 28 mars till 9 april i Guatemala under en resa med Vision For All. De insamlade mätvärdena kommer från orterna runt Antigua och Alta Verapaz. En subjektiv binokulär refraktion genomfördes på patienterna där sfärisk ekvivalens tillämpades. Refraktionsfelen definierades som hyperopi SE ≥ +0,75 D och myopi SE ≤ -0,75 D. Utrustningen som användes bestod av flipprar (+1,00 till +2,50 D),visustavla med Snellen E-hakar, provglaslåda, provbåge och journalblad. Resultat: 503 personer (311 kvinnor och 192 män) i åldrarna 10-35 år deltog. Förekomsten av hyperopi var störst på 30 %, myopi 19 % och emmetropi 51 %. Myopiförekomsten var högst i åldersgruppen 16-20 år på 27 %. Det vanligaste refraktionsfelet efter arbete var hyperopi. Slutsats: Resultatet från studien visade en högre förekomst av hyperopi än myopi hos befolkningen mellan 10-35 år i Guatemala. Det vanligast förekommande synfelet i samtliga yrkesgrupper var hyperopi. Tidigare studier från Central- och Sydamerika visar på liknande resultat med högst förekomst av hyperopi.Purpose: The aim of this study was to examine the prevalence of hyperopia and myopia among people aged 10-35 years in Guatemala. Also to investigate the prevalence of refractive errors in various occupational groups. Methods: The study was conducted from March 28 to April 9 during a journey with Vision For All. The measurements were performed in the area around Antigua and Alta Verapaz with binocular subjective refraction. Spherical equivalent refractive errors were used to quantify ametropia. The ametropia was defined as hyperopia SE > +0,75 D and myopia SE < -0,75 D. The equipment used consisted of flippers (+1,00 to +2,50 D), Snellen Eye Chart with tumbling E, trial lenses, trial frame and protocol. Results: 503 people participated (311 women and 192 men) aged 10-35 years. The prevalence of hyperopia was highest at 30 %, 19 % had myopia and 51 % had emmetropia. The incidence of myopia was highest in the age group between 16-20 years at 27 %. The most common refractive error associated with occupation was hyperopia. Conclusions: The results showed a higher prevalence of hyperopia than myopia among the population aged 10-35 years in Guatemala. The most common refractive error in the various occupational groups was hyperopia. Similar results with a higher prevalence of hyperopia can be seen in earlier studies from Central- and South America.
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Acha, Armando R. "Electroproduction of hyperons at low momentum transfer." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/1133.
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A high resolution study of the H(e,e'K+)Λ,Σ0 reaction was performed at Hall A, TJNAF as part of the hypernuclear experiment E94-107. One important ingredient to the measurement of the hypernuclear cross section is the elementary cross section for production of hyperons, Λ and Σ0. This reaction was studied using a hydrogen (i.e. a proton) target. Data were taken at very low Q2 (∼0.07 (GeV/c)2) and W∼2.2 GeV. Kaons were detected along the direction of q, the momentum transferred by the incident electron (θCM~6°). In addition, there are few data available regarding electroproduction of hyperons at low Q2 and θCM, and the available theoretical models differ significantly in this kinematical region of W. The measurement of the elementary cross section was performed by scaling the Monte Carlo cross section (MCEEP) with the experimental-to-simulated yield ratio. The Monte Carlo cross section includes an experimental fit and extrapolation from the existing data for electroproduction of hyperons. Moreover, the estimated transverse component of the electroproduction cross section of H(e,e'K+)Λ was compared to the different predictions of the theoretical models and exisiting data curves for photoproductions of hyperons. None of the models fully describe the cross-section results over the entire angular range. Furthermore, measurements of the Σ0/Λ production ratio were performed at θCM, where data are not available. Finally, data for the measurements of the differential cross sections and the Σ0/Λ production were binned in Q2, W and θCM to understand the dependence on these variables. These results are not only a fundamental contribution to the hypernuclear spectroscopy studies but also an important experimental measurement to constrain existing theoretical models for the elementary reaction.
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Heikkilä, Annele. "Studies of Light Hyperon Decay Parameters." Thesis, Uppsala universitet, Kärnfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388602.
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A basic assumption in fundamental physics is that equal amounts of matter and antimatter were created after the Big Bang. When particles and antiparticles collide, they annihilate, i.e. disappear and produce photons. Nevertheless, the universe consists mainly of matter today. To explain why all matter did not disappear, violation of CP symmetry beyond the Standard Model is required. CP symmetry means that the laws of physics are the same if particles are interchanged with antiparticles and spatial coordinates of all particles are mirrored. CP symmetry is relatively poorly tested in baryon decays. A new method to study CP symmetry in hyperon-antihyperon pairs has been developed at Uppsala University. Hyperons are baryons with one or more strange quarks. The method allows determining the decay asymmetry parameters of the hyperon and antihyperon separately if the hyperon-antihyperon pair is polarized. If any significant difference between the magnitudes of these parameters is found, the process is CP violating. The particle physics experiment BESIII in China is a suitable experiment to conduct this kind of measurements because it is a high precision experiment and has collected large data samples of hyperon-antihyperon pairs. The goal of this project was to study statistical precisions of the physics parameters that can be obtained with the new method in cases of J/ψ meson decaying into ΛΛ, Σ+Σ− and Σ0Σ0. High statistical precision is required to detect CP violation, because CP violating processes are, if they exist, expected to be rare. The main focus was to study the process e+e− → J/ψ → Σ0Σ0 → ΛγΛγ → pπ−γpπ+γ. In this process, CP symmetry can be tested in two decay processes: electromagnetic decay Σ0 → Λγ and weak decay Λ → pπ−. Only the asymmetry parameter of Λ → pπ− was studied. The study served as a validity check of the new method and ongoing analyses at BESIII. The statistical precision was studied by simulations: Monte Carlo data samples were created and then a maximum-log-likelihood fit was applied to the samples. An important component when determining the asymmetry parameters turned out to be the relative phase ∆φJ/ψ. The relative phase is one of the parameters used for determining the relation between the electric and magnetic form factors. ∆φJ/ψ is also related to the polarization of the hyperon-antihyperon pair. The study showed that the value of ∆φJ/ψ has a large impact on the uncertainties of the hyperon and antihyperon asymmetry parameters. A low value of ∆φJ/ψ resulted in high uncertainties and strong correlations between the asymmetry parameters. The formalism is different for different processes, which affects the uncertainties as well. The formalism used for the Σ0Σ0 process gives poorer parameter precision of the asymmetry parameter related to the Λ → pπ− decay than the formalism used for the ΛΛ process. Therefore, the ΛΛ process is a much more suitable process for CP studies of the Λ → pπ− decay.Ett grundantagande inom den fundamentala fysiken är att lika stora mängder av materia och antimateria skapades efter Big Bang. När partiklar och antipartiklar kolliderar, annihilerar de, dvs försvinner och producerar fotoner. Trots detta består dagens universum huvudsakligen av materia. För att förklara varför all materia inte försvann krävs ett brott mot CP-symmetrin bakom standardmodellen. CP-symmetrin innebär att fysikens lagar är desamma om man byter partiklar mot antipartiklar och speglar partikelns rumsliga koordinater. CP-symmetri i baryonsönderfall är relativt dåligt testad. En ny metod för att studera CP-symmetrin har utvecklats vid Uppsala universitet för hyperon-antihyperon par. Hyperoner är baryoner med en eller fler särkvarkar. Metoden gör det möjligt att bestämma asymmetriparametrar hos hyperon- och antihyperonsönderfall separat om hyperonantihyperonparet är polariserat. Om en signifikant skillnad mellan värden av dessa parametrar upptäcks, är processen CP-brytande. Partikelfysikexperimentet BESIII i Kina är ett lämpligt experiment för sådana här mätningar eftersom det är ett högpresicionsexperiment och har dessutom samlat in stora mängder data av hyperon-antihyperonpar. Målet för detta projekt har varit att studera de statistiska precisioner av fysikparametrar som kan nås när man använder den nya metoden i de fall där J/ψ mesonen sönderfaller till ΛΛ, Σ+Σ− och Σ0Σ0. Hög statistisk precision behövs för att upptäcka CP-brott, eftersom CP-brytande processer, om de existerar, är relativt sällsynta. Huvudfokuset var att studera processen e+e− → J/ψ → Σ0Σ0 → ΛγΛγ → pπ−γpπ+γ. I denna process kan CP-symmetri testas för två sönderfallsprocesser: det elektromagnetiska sönderfallet Σ0 → Λγ och det svaga sönderfallet Λ → pπ−. I denna rapport studerades bara asymmetriparametrarna av Λ → pπ−. Detta arbete har fungerat som validitetskontroll av den nya metoden och pågående analyser på BESIII. Den statistiska precisionen undersöktes med simuleringar: Monte Carlo datamängder skapades och sedan en maximum-log-likelihood-anpassning av datan genomfördes. En viktig komponent i bestämningen av asymmetriparametrarna visade sig vara den relativa fasen, ∆φJ/ψ. Den relativa fasen är en av de parametrar som används för att bestämma relationen mellan de elektriska och magnetiska formfaktorer. ∆φJ/ψ är också relaterad till hyperonens hyperon-antihyperonparets polarisation. I forskningsprojektet visades att ∆φJ/ψ har en stor inverkan på osäkerheterna av hyperon- och antihyperonasymmetriparametrarna. Ett lågt värde av ∆φJ/ψ resulterade i stora osäkerheter och starka korrelationer mellan asymmetriparametrarna. Formalismen är annorlunda för olika processer, vilket också påverkar osäkerheterna. Formalismen som används för Σ0Σ0-processen ger sämre parameterprecision av asymmetriparametern kopplad till sönderfallet Λ → pπ− än formalismen som används för ΛΛ-processen. Därför är ΛΛ-processen en mycket lämpligare process för att testa CP-symmetrin i Λ → pπ− sönderfallet.
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Nsio, Nzundu Tony. "Electromagnetic production of mesons and hyperons from nuclei." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1145.
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Landrum, Brian Thomas. "The Effect of Letter Size on the Accommodative Response A Thesis." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1243026823.
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Akuta, Godwin Chukwuemeka. "Prevalence of refractive errors among primary school children (7-14 years) in Motherwell Township, Eastern Cape, South Africa." Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1751.
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Thesis (MPH.) --University of Limpopo, 2015Background: Uncorrected refractive errors remain a public health problem among different population and age groups worldwide, including South Africa. Refractive error has serious visual and functional impacts on those affected. In children, refractive errors may negatively affect the academic pursuits and activities of daily living such as reading. Aims and Objectives: To determine and document the prevalence, types and magnitude together with age and gender differences of refractive errors among primary school children in Motherwell Township, Eastern Cape Province, South Africa. Methods: This was a quantitative, cross sectional refractive error study. Four hundred and twenty one (421) school children aged 7 – 14 years were randomly selected from five randomly selected schools in Motherwell Township, Eastern Cape Province, South Africa. Visual examination which included unaided and aided visual acuity (with LogMAR E chart), non-cycloplegic autorefraction, subjective refraction, internal and external examination of the eye using an ophthalmoscope was conducted. Refractive errors were measured with an autorefractor, refined subjectively and findings presented in spherical form. Hyperopia was defined as a spherical equivalent (SE) of +0.50 D or greater, myopia as spherical equivalent of -0.50 D or greater. A cylindrical power of -0.50 DC (D cylinder) or greater was considered as astigmatism. Results: The prevalence of hyperopia, myopia and astigmatism among the children were 25.2%, 18.7% and 58.0% respectively. Hyperopia ranged from +0.50 to +3.62 D and myopia ranged from -0.50 D to -20.25 D in the right eyes with a mean of -0.17 ± 1.7 D. In the left eye, hyperopia ranged from +0.50 to +2.62 D and myopia ranged from -0.50 to -20.62 D with a mean of -0.12 ± 1.7 D. Astigmatism in the right eyes ranged from -0.50 to -5.50 D with a mean of -0.6 ± 0.52 D and in the left eye ranged from -0.50 to -4.00 D with a mean of -0.6 ± 0.45 D respectively. Association between hyperopia and age was not statistically significant (p = 0.839), also refractive error and gender was statistically insignificant (p = 0.120). Against-the-rule (ATRA) astigmatism (43.4%) was more common, followed by with-the-rule (WTRA) astigmatism (39.0%) and oblique, (all other meridians) (17.6%). There was a significant association between types of astigmatism and age (p = 0.05), more so inter-gender difference in the prevalence of different types of astigmatism was not statistically significant (p = 0.774). Conclusion: The study concludes that refractive error has high prevalence of 43.9% in this children population. Astigmatism (58.0%) was more common followed by hyperopia (25.2%) v and myopia (18.7%). Although hyperopia was not age dependent, there was obvious relationship pattern between female genders and hyperopia in the present study. Population-based vision screening or at least school visual screening in the rural communities of Motherwell Township is, therefore recommended. Vision screening and proper eye examination with appropriate optical compensation will improve the activity of daily living and quality of life of those affected. Key words: Refractive error, hyperopia, myopia, astigmatism, school children
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Böcker, Matthias. "Messung der transversalen L-Polarisation [Lambda-Polarisation] mit dem HERA-B-Detektor." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971196591.
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Wendisch, Christian. "Hyperon-Produktion und -Polarisation in der Reaktion p (3,5 GeV) + Nb mit HADES." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-158395.
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Zur Erforschung des Verhaltens der Kernmaterie wurde mit dem Dielektronen-Spektrometer HADES am GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt unter anderem die Reaktion p + Nb bei 3,5 GeV kinetischer Strahlenergie untersucht. Obwohl HADES primär für den Nachweis seltener leptonischer Zerfälle der Vektormesonen ρ, ω und φ konzipiert wurde, eignet sich das Spektrometer aufgrund seiner präzisen Spurrekonstruktion auch für die Untersuchung von hadronischen Kanälen. Zum Studium der Strangeness-Signaturen in der Reaktion p + Nb wird in dieser Arbeit der im Jahr 2008 aufgezeichnete Datensatz von ca. 4,2 Milliarden Kollisionen hinsichtlich der Produktion und der dabei auftretenden Polarisation von Λ-Hyperonen untersucht. Die polarisierte Produktion von Hyperonen in Kernreaktionen mit unpolarisierten Ausgangsteilchen wurde entgegen den theoretischen Erwartungen erstmals 1976 beobachtet und fand bis heute keine allgemein akzeptierte und alle beobachteten Abhängigkeiten umfassende Erklärung auf Grundlage der starken Wechselwirkung. Es werden zunächst die theoretischen Modelle der Hyperonpolarisation diskutiert und der experimentelle Zugang erklärt. Dieser gelingt über den schwachen Zerfall des Λ-Hyperons, der als natürliches Polarimeter wirkt und somit insbesondere in Reaktionen mit unpolarisierten Nukleonen ein ideales Instrument zur Untersuchung der Polarisation darstellt. Aufgrund der großen Raumwinkelabdeckung ermöglicht HADES, Λ-Hyperonen in einem weiten Phasenraumbereich zu rekonstruieren, sodass deren Produktionsrate und Polarisation in Abhängigkeit der Observablen Transversalimpuls pt und Rapidität y analysiert werden. Aus insgesamt 1,1 Millionen rekonstruierten Λ-Hyperonen werden nach der Korrektur bezüglich der Detektorakzeptanz und -effizienz transversale Massenspektren extrahiert. Deren inverser Steigungsparameter TB (y) nimmt ein Maximum von rund 90 MeV bei y = 1, d.h. unterhalb der Schwerpunktsrapidität im Nukleon-Nukleon-Stoß (ycm = 1,12), an und fällt zu kleinen Rapiditäten deutlich schneller ab als für Teilchen im thermischen Gleichgewicht. Die Λ-Rapiditätsdichte zeigt eine asymmetrische Verteilung, die aufgrund von Mehrfachstreuung der Λ-Hyperonen hauptsächlich mit Kern-Nukleonen deutlich zur Targetrapidität verschoben ist und mit steigender Rapidität > 0,3 stark abnimmt. Auf den vollständigen Phasenraum extrapoliert, erfüllt die Produktionsrate von 0,018 ± 0,004 Λ-0 Hyperons je Ereignis, verbunden mit der Multiplizität von Ks -Mesonen und den mittels Transportmodell abgeleiteten Produktionsverhältnissen zu den übrigen Kaonen und Hyperonen, die Strangeness-Erhaltung im Mittel der gemessenen Kollisionen. Darüber hinaus zeigt das Λ-Hyperon eine signifikant negative Polarisation relativ zur Normalen seiner Produktionsebene, die über den verfügbaren Phasenraum gemittelt Px = (−10,6 ± 1,3) % beträgt und deren Betrag mit steigendem Transversalimpuls entsprechend Px (pt ) = (−0,19 ± 0,02) (GeV/c)−1 pt linear zunimmt. Die Ergebnisse bezüglich der Λ-Polarisation und Phasenraumverteilung werden mit denen anderer Experimente ähnlicher Stoßsysteme verglichen und im Rahmen von systematischen Untersuchungen mit Transportmodellen interpretiert, um Details zur Dynamik der Hyperon-Produktion in Proton-Kern-Reaktionen abzuleiten. Derzeit verfügbare Versionen der GiBUU- und UrQMD-Modelle können die experimentellen Verteilungen im Phasenraum jedoch nicht hinreichend reproduzieren. Mit der Rekonstruktion von Ξ− -Hyperonen und φ-Mesonen wird ein Ausblick auf weiterführende Studien zur Strangeness-Produktion in Nukleon-Kern-Stößen gegebenWith the dielectron spectrometer HADES, located at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, p + Nb reactions at a kinetic beam energy of 3.5 GeV were measured to study the behavior of nuclear matter. Although primarily designed for the detection of rare leptonic decays of the light vector mesons ρ, ω and φ, the spectrometer renders itself very well suited for the investigation of hadrons, due to its excellent tracking capability. This thesis presents results of the production and polarization of strange Λ hyperons in about 4.2 billion reactions of p + Nb recorded in 2008. In contrast to theoretical expectations, the polarized production of hyperons was observed in 1976 for the first time in nuclear reactions with unpolarized beams. Based on the fundamental properties of strong interaction, to date no single explanation exists describing all dependencies of the observed hyperon polarization. Therefore, common theoretical models of hyperon polarization are introduced. Acting as a natural polarimeter, the Λ hyperon represents an excellent tool to study the phenomenon of hyperon polarization especially in reactions with unpolarized beams and targets. Hence, the experimental technique for extracting the polarization using the weak decay of the Λ hyperon is explained. Due to a large solid angle coverage, HADES allows for the reconstruction of hadrons within a wide phase space range. Consequently, a double-differential analysis of the polarization and production probability as a function of transverse momentum pt and rapidity y is performed. In total, 1.1 million Λ hyperons are reconstructed and corrected for detector acceptance and efficiency. The inverse slope parameter TB is extracted from transverse mass spectra. Its rapidity dependence TB (y) shows a maximum of 90 MeV at y = 1, i.e. below the center-of-mass rapidity of the nucleon-nucleon collision ycm = 1.12, and a stronger decrease to lower rapidities than particles in thermal equilibrium. The Λ rapidity density shows an asymmetric distribution, shifted towards target rapidity, which is probably caused by multiple scattering on target nucleons. Extrapolated to the full phase space, the total multiplicity of 0.018 ± 0.004 Λ hyperons per event satisfies strangeness conservati- 0 on on average. For that purpose, the Ks production rate from another analysis and ratios to the other, unmeasured, strange hadrons, derived from transport simulations, are taken into account. Furthermore, the Λ hyperon shows a significant negative polarization perpendicular to its production plane, which amounts to Px = (−10.6 ± 1.3) % averaged over the phase space accessible to HADES. The measured Λ polarization increases almost linearly with increasing transverse momentum pt , according to Px (pt ) = (−0.19 ± 0.02) (GeV/c)−1 pt . In order to spot details on the dynamics of hyperon production in proton-nucleus reactions, the results on Λ polarization and phase space distribution are compared to those of similar reactions. Additionally, a systematic investigation with transport model simulations is performed. The experimental distributions can not be reproduced sufficiently well by the presently available GiBUU and URQMD models. Moreover, an outlook on further studies of strangeness production in nucleon-nucleus collisions by reconstruction of Ξ− hyperons and φ mesons is given
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Veerasamy, Saravanan. "Valdiation of BaBar tracking software using lambda hyperon." Thesis, University of Iowa, 2007. http://ir.uiowa.edu/etd/141.
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Gifford, Paul Optometry & Vision Science Faculty of Science UNSW. "Short term refractive and corneal topographic changes in hyperopic orthokeratology." Publisher:University of New South Wales. Optometry & Vision Science, 2009. http://handle.unsw.edu.au/1959.4/43760.
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Although there is considerable published research on the efficacy and corneal response to orthokeratology (OK) lenses that flatten corneal curvature to correct myopia, the effects of OK lenses that attempt to steepen corneal curvature to correct hyperopia are poorly understood. This project investigated the effects of hyperopic OK lens wear on corneal shape, refraction and vision. Open-eye and closed-eye overnight studies were conducted with proprietary hyperopic OK lenses, and these led to the development of an experimental hyperopic OK lens design which allowed manipulation of individual lens design parameters. Changes to refraction and best corrected visual acuity (BCVA), corneal topography (Medmont E300), and the profile of total and stromal corneal thickness (Holden-Payor optical pachometer) were measured over periods up to one week of overnight lens wear. Most refractive change occurred after the first night of wear, with increasing effect towards one week. Retention of effect at the end of the day increased with more nights of lens wear. BCVA decreased with longer periods of lens wear. Greater inter-subject variability in effect was found with higher refractive targets. The central cornea steepened and para-central cornea flattened producing a central steepening zone (CSZ) surrounded by a para-central annular flattened zone. CSZ diameter reduced with longer periods of lens wear, and this was significantly associated with decreases in high and low contrast BCVA. There was no change in central corneal thickness beyond the normal overnight lens induced hypoxic edema response. Once edema had resolved thinning of the para-central corneal epithelium was found which resulted in an overall thinning of the para-central cornea. Although central lens fenestrations did not affect the hyperopic OK response, a stronger relationship between changes to apical corneal curvature and refraction resulted. This supports the conclusion that the hyperopic OK effect is due to molding of the corneal surface towards alignment with the lens back surface. Similarities to the pattern of clinical change in myopic OK suggest that a similar corneal molding mechanism occurs in myopic OK. BCVA loss prevented longer term studies and needs to be resolved if hyperopic OK is to become established as a viable clinical technique.
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Demey, Michiel. "The polarization of Lambda\0 hyperons in quasi-real photoproduction." [S.l. : Amsterdam : s.n] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/44851.
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Wiesmann, Michael. "A silicon microstrip detector for COMPASS and a first measurement of the transverse polarization of L0-hyperons [Lambda-0-hyperons] from quasi-real photo-production." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=970935900.
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Thomé, Erik. "Multi-Strange and Charmed Antihyperon-Hyperon Physics for PANDA." Doctoral thesis, Uppsala universitet, Kärnfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-182450.
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The prospects of studying multi-strange and charmed antihyperon-hyperon physics and CP violation in hyperon decays in the upcoming PANDA experiment at FAIR, Germany, have been studied in this thesis. The angular dependence on polarisation parameters in the decay of the spin 3/2 Omega hyperon was calculated using the density matrix formalism. Expressions for the angular distributions in the Ω -> ΛK and the subsequent Λ -> pπ decays were derived. Simulations were performed for the pbar p -> Ξ+ Ξ-, pbar p -> Ω+Ω- and pbar p -> Λc-Λc+ reactions. Special attention was given to the reconstruction of spin variables. It is shown that PANDA will register tens of events per second for the pbar p -> Ξ+Ξ- reaction. This should be compared to the previously existing data of a handfull of events. For the other two reactions the event rates will be lower, but still reasonably high. This will be the first measurements of these reactions. It is shown that spin variables can be reconstructed in all three reactions for all production angles of the hyperons. Simulations concerning the possibility to measure CP violation parameters in hyperon decays were also made for the reactions pbar p- > Λbar Λ and pbar p -> Ξ+Ξ-. It was found that false signals from detector asymmetries disappears if no particle identification criterium is used and the analysis is restricted to events were the hyperon decays occur close to the beam axis. The effect of the magnetic field in the PANDA detector on the measurement of hyperon spin variables was investigated for the case of pbar p -> Λbar Λ. The effect was observed to be small for polarisation and negligible for spin correlations.
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Barton, Robert Allan. "Multi-strange hyperon production in relativistic heavy -ion collisions." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367744.
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Cooke, Ashley Noel. "Lattice QCD study of octet hyperon semi-leptonic decays." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9647.
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We present a calculation of vector and axial-vector form factors for each of the octet hyperon semi-leptonic transition matrix elements by using the techniques of lattice QCD where simulations were performed with Nf = 2 + 1 flavours of dynamical O(a)-improved Wilson fermions. We also study the electromagnetic form factors, axial charges and other properties of octet baryons. Errors due to extrapolation to zero transferred momentum are reduced by applying a twist to the boundary conditions on the lattice. Our form factor results compare favourably with experiment and other lattice QCD determinations. By considering an expansion about the SU(3)-flavour symmetric limit we seek to investigate and quantify the symmetry breaking effects in these matrix elements due to the mass splitting between the strange and light quarks. We find good agreement with the Ademollo-Gatto theorem for the vector form factor, a measurable amount of breaking in the axial-vector form factor and significant effects in the weak magnetism form factor. Knowledge of the parameterisation of SU(3)-flavour symmetry breaking allows for a series of constrained fits to be made to the form factor results which are used to arrive at a 'baryonic' estimation of the Cabibbo-Kobayashi-Maskawa matrix element |Vus|.
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Moosbrugger, Ulrich. "Messung der semileptonischen Q0-Zerfälle [Xi-0-Zerfälle] mit dem NA48/1-Detektor." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976129868.
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Kutsche, Ralf. "Untersuchungen der In-Medium-Eigenschaften von K0S-Mesonen und L-Hyperonen [Lambda-Hyperonen] an der Produktionsschwelle." [S.l. : s.n.], 1999. http://elib.tu-darmstadt.de/diss/000039/kutsche.pdf.
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Karsch, Leonhard. "Untersuchungen zu den Reaktionen pp n K + Sigma + und pp p K 0 Sigma +." [S.l. : s.n.], 2005. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11947673.
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Yilmaz, Seval. "Untersuchung von Hornhautoberfläche und Hornhautbrechkraft nach LASIK zur Behandlung der Hyperopie /." Frankfurt a.M, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000259459.
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Ryan, Garrett. "Maximum Mass Restraint of Neutron Stars: Quarks, Pion, Kaons, and Hyperons." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1535.
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This thesis explores the topic of maximum mass stability of neutron stars. The outer structure is detailed and explores nuclear pasta phases, the neutron drip line, and density transitions of matter in the crust and atmosphere layers. Other discussion points include superfluids in the crust and core, vortex roles in neutron stars, and magnetic field effects on the EOS in neutron stars. The inner core is studied in much more detail due to its significant role in EOS. The variety of stars include pion condensate stars, kaon condensate stars, npeu stars, npeu stars with the inclusion of hyperons, quark-hybrid stars, and strange stars. Included with these is a description of nucleon-nucleon, nucleon-nucleon-nucleon interactions, the appearance factors that affect hyperon species, and the formation process of kaons, pions, quarks, and hyperons. The ending EOS are compared with their maximum mass values to determine which ones are likely to limit the mass of neutron stars.
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Marouelli, Peter [Verfasser]. "Messung der Lebensdauer des 0 -Hyperons mit dem NA48-Detektor / Peter Marouelli." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2005. http://d-nb.info/1225685281/34.
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Liu, Yining. "Design of an Optical Response System for Characterization of Hyperoped Silicon Photodetectors." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1461944376.
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Gabrielyan, Marianna. "Measurement of the Induced Polarization of Lambda(1116) in Kaon Electroproduction with CLAS." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/619.
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The CLAS Collaboration is using the p(e, e′ K+ p)π- reaction to perform a measurement of the induced polarization of the electroproduced Λ(1116). The parity-violating weak decay of the Λ into pπ- (64%) allows extraction of the recoil polarization of the Λ. The present study uses the CEBAF Large Acceptance Spectrometer (CLAS) to detect the scattered electron, the kaon, and the decay proton. CLAS allows for a large kinematic acceptance in Q2 (0.8 ≤ Q2 ≤ 3.5 GeV2 ), W (1.6 ≤ W ≤ 3.0 GeV), as well as the kaon scattering angle. In this experiment a 5.499 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. The goal is to map out the kinematic dependencies for this polarization observable to provide new constraints for theoretical models of the electromagnetic production of kaon-hyperon final states. Along with previously published photo- and electroproduction cross sections and polarization observables from CLAS, SAPHIR, and GRAAL, these data are needed in a coupled-channel analysis to identify previously unobserved s-channel resonances.
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Alexandre, Didier. "Hyperon production in p-Pb collisions with ALICE at the LHC." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6924/.
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This thesis discusses the production of the multi-strange, charged Ξ and Ω baryons in proton-lead (p-Pb) collisions at a centre-of-mass energy of 5.02 TeV. The transverse momentum, P\(_T\), distributions are analysed as a function of event multiplicity. A hydrodynamical model based on statistical physics reproduces the shapes of the multi-strange p\(_T\)spectra, in conjunction with the spectra of lighter hadrons, in high multiplicity data. The good agreement is an indication of collective behaviour by all particles inside a system in thermal equilibrium, consistent with the picture of the build {up of a radially outward expansion due to an initially dense medium. These results are reminiscent of the observations made in lead-lead (Pb-Pb) collisions, which are explained by the formation of a Quark-Gluon Plasma. In addition, the p\(_T\)-integrated yields of the hyperons are reported on, revealing a steady increase as a function of multiplicity. An enhancement with respect to non-strange hadrons is observed, and the Ξ/π and Ω/π ratios in high multiplicity p-Pb data approach those measured in central Pb-Pb collisions. The Ξ/π ratio is comparable with the calculations from a thermal model for strangeness saturation, whereas the Ω/π ratio deviates from that value by 2σ.
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Farooq, Saima. "Antineutrino-induced charge current quasi-elastic neutral hyperon production in ArgoNeuT." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32845.
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Doctor of PhilosophyDepartment of Physics
Timothy A. Bolton
This dissertation presents the first topological study of the charge current quasi-elastic (CCQE) neutral hyperon production induced by antineutrinos in the ArgoNeuT detector, a liquid argon time projection chamber (LArTPC) at Fermilab, using 1.20 × 10²⁰ protons-on- target (POT), in the NuMI beam operating in the low energy antineutrino mode. The total cross section for the CCQE neutral hyperon production is reported at the mean production energy of 3.42 GeV. The event yield in data is consistent with the predicted cross section, σ = 2.7 × 10−40 cm²: σ(CCQE[subscript Λ0+Σ0] ) = (3.7 ± 1.9(stat.) ± 1.5 (sys.)) × 10⁻⁴⁰ cm². The study sets a 90% confidence level (C.L.) upper limit on the total cross section of CCQE neutral hyperon production: σ(CCQE[subscript Λ0+Σ0] ) < 7.3 ×10⁻⁴⁰ cm² at 90% C.L.
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Jones, Nathan. "Using Hyperopia Measurements to Predict Need for Surgery in Children with Accommodative Esotropia." Thesis, The University of Arizona, 2018. http://hdl.handle.net/10150/627175.
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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.Background: Esotropic strabismus is a condition in which the eyes are not properly aligned with each other. In children, uncorrected esotropia may result in permanent loss of vision due to amblyopia, a condition where the nonpreferred, crossing eye is suppressed. Early identification and treatment of esotropia in children is critical, as doing so may prevent permanent loss of vision.
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Reischl, Andreas Johannes. "Quasi-real photo-production of hyperons and their impact on lambda polarization measurements." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/45260.
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Koivula, Annemari. "Long-term results of phakic refractive lenses for correction of myopia and hyperopia /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-424-2/.
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Macfadden, Lucy. "Differences in the optical and physical characteristics of the eye in myopia hyperopia." Thesis, Glasgow Caledonian University, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606549.
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Peripheral retinal characteristics have been shown recently to have an influence upon refractive error development, specifically myopia. Studies of peripheral refraction have shown that emmetropic subjects typically display a myopic peripheral refraction, whereas myopic subjects have been found to have relative hyperopic refraction in the periphery. Myopic and hyperopic subjects were recruited for the experiments detailed in this thesis, from the student population at Glasgow Caledonian University. Previous studies on human subjects have generally made comparisons between myopic and emmetropic subject groups. Our study will contribute significantly to the knowledge in this area by extending the investigations to include hyperopic subject groups. Our results show significant differences in peripheral retinal shape between hyperopic and myopic subjects. Peripheral retinal shape in hyperopia shows symmetry between the temporal and nasal retina. In contrast, the myopic subjects show significant asymmetry between temporal and nasal retinal shape (Chapters 4 and 5). We also show that eye rotation significantly alters peripheral retinal shape in myopic subjects but not in hyperopic subjects. These findings indicate structural differences between myopic and hyperopic eyes worthy of further investigation. Monochromatic higher order aberrations (MHOA) were investigated in myopic and hyperopic subjects. Analyzed Zernike coefficients of the third, fourth and fifth orders show the myopic and hyperopic subjects display a similar profile. Interestingly when the lens is forced to either relax as a result of the instillation of cyclopentolate hydrochloride (Chapter 7) or accommodate (Chapter 6) the MHOA are significantly altered. The most significant change is seen in the fourth order spherical aberration. This work has identified significant structural and internal differences between subjects with myopia and those with hyperopia thus giving further insight into the optical and physical differences that exist between the myopic and hyperopic eye. With hyperopic eyes often displaying a stable refractive error and rarely going on to develop myopia the key to investigating myopic development may be further investigation of hyperopia and any differences that may exist.
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Chien, Andrew Lawrence. "Inclusive rates and spectra of the lambda, cascade, and omega hyperons at BaBar." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1581435641&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Christian, Parul. "GABAergic modification of myopic and hyperopic ocular tissue effects on scleral fibroblast growth." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/54639/1/Parul_Christian_Thesis.pdf.
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Purpose: Myopia is a common eye disorder affecting up to 90% of children in South East Asia and 30% of the population worldwide. Myopia of high severity is a leading cause of blindness around the world (4th to 5th most common). Changes and remodelling of the sclera i.e. increase cellular proliferation & increase protein synthesis within scleral cells (↑ scleral DNA) and thinning and lose of extracellular matrix of sclera (↓ scleral GAG synthesis) have been linked to myopic eye growth in animal models. Signals acting on the sclera are thought to originate in the retina, and are modulated by the retinal pigment epithelium (RPE) with limited evidence suggesting that the RPE can modify scleral cell growth in culture. However, the mechanism of retinal signal transmission and the role of posterior eye cup tissue, including the RPE, in mediating changes in scleral fibroblast growth during myopia development are unclear. Retinal transmitter systems are critically involved in pathways regulating eye growth, which ultimately lead to alterations in the sclera if eye size is to change. A dopaminergic agonist and muscarinic antagonists decrease the proliferation of scleral chondrocytes when co-cultured with chick’s retinal pigment epithelium (RPE). GABA receptors have recently been localised to chick sclera. We therefore hypothesised that posterior eye cup tissue from myopic eyes would stimulate and from hyperopic eyes would inhibit growth of scleral fibroblasts in vitro and that GABAergic agents could directly interact with scleral cells or indirectly modify the effects of myopic and hyperopic posterior eye cup tissue on scleral fibroblast growth.
Method: Fibroblastic cells obtained from 8-day-old chick sclera were used to establish cell banks. Two major experiments were performed.
Experiment 1: To determine if posterior eye cup tissues from myopic eye stimulates and hyperopic eye inhibits scleral cell proliferation, when co-cultured with scleral cells in vitro. This study comprised two linked experiments, i) monocular visual treatments of FDM (form-deprivation myopia), LIM (lens-induced myopia) and LIH (lens-induced hyperopia) with assessment of the effect of full punch eye cup tissue on DNA and GAG synthesis by cultured chick scleral fibroblasts, and ii) binocular visual treatments comprising LIM and LIH with assessment of the effect of individual layers of eye cup tissues (neural retina, RPE and choroid) on cultured chick scleral fibroblasts. Visual treatment was applied for 3 days.
Experiment 2: To determine the direct interaction of GABA agents on scleral cell growth and to establish whether GABA agents modify the stimulatory/inhibitory effect of myopic and hyperopic posterior eye cup tissues on cultured scleral cell growth in vitro. Two linked experiments were performed. i) GABA agonists (muscimol and baclofen) and GABA antagonists (bicuculine (-), CGP46381 and TPMPA) were added to scleral cell culture medium to determine their direct effect on scleral cells. ii) GABAergic agents (agonists and antagonists) were administered to scleral fibroblasts co-cultured with posterior eye cup tissue (retina, RPE, retina/RPE, RPE/choroid). Ocular tissues were obtained from chick eyes wearing +15D (LIH) or -15D lenses (LIM) for 3 days.
In both experiments, tissues were added to hanging cell culture insert (pore size 1.0ìm) placed over each well of 24 well plates while scleral cells were cultured in DMEM/F12, Glutamax (Gibco) plus 10% FBS and penicillin/streptomycin (50U/ml)) and fungizone (1.25ug/ml) (Gibco), at seeding density of 30,000 cells/well at the bottom of the well and allowed to grow for 3 days. Scleral cells proliferation rate throughout the study was evaluated by determining GAG and DNA content of scleral cells using Dimethylmethylene blue (DMMB) dye and Quant-iTTm Pico Green® dsDNA reagent respectively.
Results and analysis: Based on DNA and GAG content, there was no significant difference in tissue effect of LIM and LIH eyes on scleral fibroblast growth (DNA: 8.4 ± 1.1μg versus 9.3 ± 2.3 μg, p=0.23; GAG: 10.13 ± 1.4 μg versus 12.67 ± 1.2 μg, F2,23=6.16, p=0.0005) when tissues were obtained from monocularly treated chick eyes (FDM or +15D lens or -15D lens over right eyes with left eyes untreated) and co-cultured as full punch. When chick eyes were treated binocularly with -15D lens (LIM) right eye and +15D lens (LIH) left eyes and tissue layers were separated, the retina from LIM eyes did not stimulate scleral cell proliferation compared to LIH eyes (DNA: 27.2 ± 6.7 μg versus 23.2 ± 1.5 μg, p=0.23; GAG: 28.1 ±3.7 μg versus 28.7 ± 4.2 μg, p=0.21). Similarly, the LIH and LIM choroid did not produce a differential effect based on DNA (LIM 46.9 ± 6.4 μg versus LIH 53.5 ± 4.7 μg, p=0.18), however the choroid from LIH eyes induced higher scleral GAG content than from LIM eyes (32.5 ± 6.7 μg versus 18.9 ± 1.2 μg, p=0.023). In contrast, the RPE from LIM eyes caused a significant increase in fibroblast proliferation whereas the RPE from LIH eyes was relatively inhibitory (72.4 ± 6.3 μg versus 27.9 ± 2.3 μg, F1, 6=69.99, p=0.0005). GAG data were opposite to DNA data e.g. the RPE from LIH eyes increased (33.7 ± 7.9 μg) while the RPE from LIM eyes decreased (28.2 ± 3.0 μg) scleral cell growth (F1, 6=13.99, p=0.010).
Based on DNA content, GABA agents had a small direct effect on scleral cell growth; GABA agonists increased (21.4 ± 1.0% and 18.3 ± 1.0% with muscimol and baclofen, p=0.0021), whereas GABA antagonists decreased fibroblast proliferation (-23.7 ± 0.9% with bicuculine & CGP46381 and -28.1 ± 0.5% with TPMPA, p=0.0004). GABA agents also modified the effect of LIM and LIH tissues (p=0.0005).The increase in proliferation rate of scleral fibroblasts co-cultured with tissues (RPE, retina, RPE/retina and RPE/choroid) from LIM treated eyes was enhanced by GABA agonists (muscimol: 27.4 ± 1.2%, 35.8 ± 1.6%, 8.4 ± 0.3% and 11.9 ± 0.6%; baclofen: 27.0 ± 1.0%, 15.8 ± 1.5%, 16.8 ± 1.2% and 15.4 ± 0.4%, p=0.014) whereas GABA antagonists further reduced scleral fibroblasts growth (bicuculine: -52.5 ± 2.5%, -36.9 ± 1.4%, -37.5 ± 0.6% and -53.7 ± 0.9%; TPMPA: 57.3 ± 1.3%, -15.7 ± 1.2%, -33.5 ± 0.4% and -45.9 ± 1.5%; CGP46381: -51.9 ± 1.6%, -28.5 ± 1.5%, -25.4 ± 2.0% and -45.5 ± 1.9% respectively, p=0.0034). GAG data were opposite to DNA data throughout the experiment e.g. GABA agonists further inhibited while antagonists relatively enhanced scleral fibroblasts growth for both LIM and LIH tissue co-culture. The effect of GABA agents was relatively lower (p=0.0004) for tissue from LIH versus LIM eyes but was in a similar direction. There was a significant drug effect on all four tissue types e.g. RPE, retina, RPE/retina and RPE/choroid for both LIM and LIH tissue co-culture (F20,92=3.928, p=0.0005). However, the effect of GABA agents was greatest in co-culture with RPE tissue (F18,36=4.865, p=0.0005).
Summary and Conclusion: 1) Retinal defocus signals are transferred to RPE and choroid which then exert their modifying effect on scleral GAG and DNA synthesis either through growth stimulating factors or directly interacting with scleral cells in process of scleral remodeling during LIM and LIH visual conditions. 2) GABAergic agents affect the proliferation of scleral fibroblasts both directly and when co-cultured with ocular tissues in vitro.
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Pérez, Andrade Gabriela. "Production of the Σ0-bar hyperon in the PANDA experiment at FAIR." Thesis, Uppsala universitet, Kärnfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-375552.
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The PANDA experiment is one of the main pillars of the Facility for Antiproton and Ion Research (FAIR), currently under construction in Darmstadt, Germany. PANDA will be a fixed target experiment designed for the study of non-perturbative phenomena of the strong interaction. Strange hyperon production is governed by m(s) ~ 100 MeV, which corresponds to the confinement domain. Thus, hyperons are suitable probes in this energy region. This work is a simulation study focused on the feasibility of studying the production of Σ0-bar and Λ hyperons in the pbar p -> Σ0-bar Λ reaction with the PANDA detector. A 10^4 events sample simulated at p(beam) = 1.771 GeV/c is used to perform a single-tag (inclusive) and a double-tag (exclusive) event selection. From the former, it is concluded that the single-tag method does not provide with the clean signal required for spin observables extraction. In contrast, exclusive event selection provides with a signal reasonably clean from combinatorial background and completely clean from generic hadronic background events. A signal (Σ0-bar Λ) reconstruction efficiency of ε = 5.3 ± 0.2 % is obtained for exclusive event selection. The corresponding signal to background ratio is S/B(Total) ~ 6 and the significance value is ~ 21. In addition, an exclusive event selection is performed on a 10^4 events sample simulated at p_(beam) = 6 GeV/c. Almost all the generic hadronic background events are removed by the applied selection criteria. At this beam momentum, the obtained signal efficiency is ε = 6.1 ± 0.3%, the signal to total background ratio is S/B(Total) ~ 4 and the significance is ~22. Both efficiencies are smaller compared to a previous simulation study on this channel, but are large enough to enable a study of the exclusive production of the pbar p -> Σ0-bar Λ reaction at PANDA. The difference between the results of this thesis work and the previous work is attributed to the more realistic implementation of the signal production mechanism, as well as the detector and reconstruction algorithms.
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Grape, Sophie. "PWO Crystal Measurements and Simulation Studies of Anti-Hyperon Polarisation for PANDA." Licentiate thesis, Uppsala universitet, Kärnfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-142861.
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The Gesellschaft für Schwerionenforschung (GSI) facility in Darmstadt, Germany, will be upgraded to accommodate a new generation of physics experiments. The future accelerator facility will be called FAIR and one of the experimentsat the site will be PANDA, which aims at performing hadron physics investigations by colliding anti-protons with protons. The licentiate thesis consistsof three sections related to PANDA. The first contains energy resolutionstudies of PbWO4 crystals, the second light yield uniformity studies of PbWO4 crystals and the third reconstruction of the lambda-bar-polarisation in the PANDA experiment. Two measurements of the energy resolution were performed at MAX-Lab in Lund, Sweden, with an array of 3x3 PbWO4 crystals using a tagged photon beam with energies between 19 and 56 MeV. For the April measurement, the crystals were cooled down to -15 degrees C and for the September measurement down to -25 degrees C. The measured relative energy resolution,
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Pérez, Andrade Gabriela. "Detector signatures of Xi and anti-Xi hyperons in the Forward Spectrometer at PANDA." Thesis, Uppsala universitet, Kärnfysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-349678.
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Bono, Jason S. "First Time Measurements of Polarization Observables for the Charged Cascade Hyperon in Photoproduction." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1520.
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The parity violating weak decay of hyperons offers a valuable means of measuring their polarization, providing insight into the production of strange quarks and the matter they compose. Jefferson Lab’s CLAS collaboration has utilized this property of hyperons, publishing the most precise polarization measurements for the Λ and Σ in both photoproduction and electroproduction to date. In contrast, cascades, which contain two strange quarks, can only be produced through indirect processes and as a result, exhibit low cross sections thus remaining experimentally elusive.
At present, there are two aspects in cascade physics where progress has been minimal: characterizing their production mechanism, which lacks theoretical and experimental developments, and observation of the numerous excited cascade resonances that are required to exist by flavor SU(3)F symmetry. However, CLAS data were collected in 2008 with a luminosity of 68 pb−1 using a circularly polarized photon beam with energies up to 5.45 GeV, incident on a liquid hydrogen target. This dataset is, at present, the world’s largest for meson photoproduction in its energy range and provides a unique opportunity to study cascade physics with polarization measurements.
The current analysis explores hyperon production through the γp → K+K+Ξ− reaction by providing the first ever determination of spin observables P, Cx and Cz for the cascade. Three of our primary goals are to test the only cascade photoproduction model in existence, examine the underlying processes that give rise to hyperon polarization, and to stimulate future theoretical developments while providing constraints for their parameters. Our research is part of a broader program to understand the production of strange quarks and hadrons with strangeness. The remainder of this document discusses the motivation behind such research, the method of data collection, details of their analysis, and the significance of our results.
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Britsch, Markward. "Hyperon production in proton-nucleus collisions at 42 GeV center of mass energy." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10633916.
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Steirud, Emelie. "Hur skiljer sig tjockleken på retinas nervfiberlager mellan emmetroper, myoper samt hyperoper? : En OCT studie." Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19753.
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Syfte: Syftet med studien var att utreda sambandet mellan ögats ametropi och tjockleken på retinas nervfiberlager (RNFL) med optical coherence tomography teknik (OCT). Metod: I studien ingick 30 försökspersoner med olika typ av ametropi. En inledande mätning med autorefraktor genomfördes och styrkorna värderades därefter av i provbåge. På så sätt erhölls ett resultat på storleken på den eventuella ametropin. Därefter utfördes den huvudsakliga mätningen av nervfiberlagets tjocklek med OCT kameran OPKO Spectral OCT Slo på samtliga försökspersoners högerögon. Försökspersonerna delades in i fem olika grupper utifrån befintlig ametropi. Resultat: En signifikant korrelation mellan ögats ametropi och det retinala nervfiberlagrets tjocklek hittades då resultaten från alla 30 försökspersoner analyserades mot varandra. Ingen signifikant skillnad för RNFL-tjocklekens medelvärde för hela det skannade området kunde dock visas mellan de olika diagnostiska gruppernas medelvärde i denna studie, förutom jämförelsen mellan de högre hyperoperna mot emmetroperna då en signifikant skillnad kunde ses (p < 0,05). Slutsats: Denna studie visar att det går att statistiskt säkerställa ett samband mellan ögats ametropi och det retinala nervfiberlagrets tjocklek. Nervfiberlagret i retina blir tunnare med ökad myopi och tjockare med ökad hyperopi.
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Wong, Sharon Tsau-Yuen. "Effects of induced myopia and hyperopia on dopaminergic and serotonergic amacrine neurons in chick retina." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ32867.pdf.
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Plaszczynski, Stéphane. "Etude de la production des hyperons a lep (delphi) et recherche de baryons beaux etranges." Paris 7, 1994. http://www.theses.fr/1994PA077178.
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A partir de l'analyse des donnees enregistrees a lep avec le detecteur delphi en 1991-1992-1993, un signal de baryons beaux etranges est obtenu par l'etude des correlations de charge entre un hyperon xi et un lepton d'un meme jet. Les diverses sources conduisant a cet etat final sont etudiees. La probabilite que ce signal soit issu de fluctuations d'autres sources que des baryons beaux est estimee a 10#-#4. Une evaluation de la duree de vie des baryons beaux etranges est effectuee. Les taux de production inclusifs de plusieurs hyperons sont egalement mesures
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Molyneux, Richard. "Hyperset approach to semi-structured databases and the experimental implementation of the query language Delta." Thesis, University of Liverpool, 2009. http://livrepository.liverpool.ac.uk/1109/.
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This thesis presents practical suggestions towards the implementation of the hyperset approach to semi-structured databases and the associated query language Delta. This work can be characterised as part of a top-down approach to semi-structured databases, from theory to practice. The main original part of this work consisted in implementation of the hyperset Delta query language to semi-structured databases, including worked example queries. In fact, the goal was to demonstrate the practical details of this approach and language. The required development of an extended, practical version of the language based on the existing theoretical version, and the corresponding operational semantics. Here we present detailed description of the most essential steps of the implementation. Another crucial problem for this approach was to demonstrate how to deal in reality with the concept of the equality relation between (hyper)sets, which is computationally realised by the bisimulation relation. In fact, this expensive procedure, especially in the case of distributed semi-structured data, required some additional theoretical considerations and practical suggestions for efficient implementation. To this end the 'local/global' strategy for computing the bisimulation relation over distributed semi-structured data was developed and its efficiency was experimentally confirmed. Finally, the XML-WDB format for representing any distributed WDB as system of set equations was developed so that arbitrary XML elements can participate and, hence, queried by the -language. The query system with the syntax of the language and several example queries from this thesis is available online at http://www.csc.liv.ac.uk/˜molyneux/t/
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Södergård, Olof, and Tom Manselin. "Effekter av intermittent syretillförsel under sex veckors löpträning." Thesis, Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:gih:diva-3226.
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Syfte och frågeställningar Syftet med denna studie var att undersöka vilka fysiologiska effekter sex veckors högintensiv intervallträning (HIIT) på löpband med hyperoxi (>20,94 % syre) samt med normoxi (normal rumsluft) hade under kontrollerade former. De frågeställningar som hjälpte att besvara syftet var: (1) Hur förändras VO2max efter sex veckors högintensiv träning? (2) Hur förändras prestationen efter sex veckors högintensiv träning? (3) Hur påverkas löpekonomin av sex veckors HIIT? (4) Vilka fysiologiska effekter gav hyperoxiträning? Metod I studien deltog initialt åtta manliga vältränade löpare varav fem stycken fullföljde studien. Karaktäristiken för de fem försökspersonerna (FP) var: ålder (år) 27,6 ± 5,8, längd (cm)180,9 ± 5,0, vikt (kg) 68,6 ± 6,2, årsbästa 10 km (mm:ss) 33:44 ± 01:11 och VO2max (ml/kg/min) 69,0 ± 2,3. FP delades in i test- och kontrollgrupp och studien var utformat som en single-blind. Under en sex veckors träningsperiod tränade FP två gånger per vecka under kontrollerade former i laboratoriemiljö på löpband. Träningen bestod av HIIT i 3-6 st x 6 min arbete med 4 min vila. Hyperoxigruppen fick tillgång till intermittent extra syre genom Oxelerate. Normoxigruppen fick normal rumsluft administrerad genom samma apparatur. Det gjordes tester innan och efter träningsperioden som bestod av ett submaximalt test för att fastställa laktattröskel och löpekonomi, samt ett maximalt syreupptagningstest där även prestationen mättes. Resultat De signifikanta (P <0,05) resultat studien kunde visa på var att prestationen förbättrades för alla FP efter sex veckors HIIT (414,6 ± 85,8 till 460,6 ± 80,4 sekunder). Maxlaktatet blev signifikant högre hos hyperoxigruppen (17,7 %) och signifikant lägre hos normoxigruppen (-19,1 %). Slutsats HIIT gav en signifikant ökad prestation för alla FP. Hyperoxi hade bara effekt på maxlaktat. Löpekonomin och VO2max var oförändrad efter sex veckors HIIT.Uppsatsen tilldelades stipendiemedel ur Överste och Fru Adolf Janssons fond för HT 2014.
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Niiyama, Masayuki. "Photoproduction of Λ(1405) and Σ0(1385) hyperons on the proton at Eγ=1.5-2.4 GeV." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/124372.
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