L'expérience Double Chooz a pour but de mesurer l'angle de mélange leptonique θ₁₃ avec précision. Pour ce faire, l'expérience met à profit deux détecteurs identiques -- remplis de liquide scintillant dopé au gadolinium -- afin d'étudier les $antinue$ produits par les deux réacteurs nucléaires de 4.25GWth de la centrale de Chooz. Le détecteur lointain -- situé à une distance moyenne de $SI{1050}{m}$ des coeurs -- prend des données depuis Avril 2011. Le détecteur proche -- à une distance moyenne de 400m des coeurs -- observe les réacteurs depuis Décembre 2014. Le paramètre de mélange θ₁₃ conduit à la disparition d'$antinue$, lorsque ceux-ci voyagent des coeurs jusqu'aux sites de détection; la dépendance en énergie de ce déficit permet d'extraire la valeur de sin² 2θ₁₃, par ajustement. Les systématiques de détection, ainsi que l'incertitude sur la prédiction du flux $antinue$, sont formidablement réduites par le biais de corrélations entre les détecteurs et la configuration iso-flux du site. Par conséquent, la précision relative à la mesure de θ₁₃ est dominée par les incertitudes sur les bruits de fond et sur la normalisation relative des taux d'$antinue$. Le bruit de fond principal provient de la désintégration des émetteurs βn -- produits par spallation des muons -- dans le détecteur lui-même. Les spectres de ces isotopes cosmogéniques ont été simulés et complétés par un traitement d'erreur rigoureux. Ces prédictions sont en bon accord avec les données, elles-mêmes extraites à l'aide d'un veto actif, dont la performance a été étudiée pour les deux sites. Le taux d'évènements cosmogéniques restant parmi les candidats $antinue$ a également été estimé. En outre, la normalisation relative du taux d'$antinue$, liée aux nombres de protons dans les cibles de chaque détecteur, a été évaluée. Tous ces travaux se sont inscrits au sein des premières analyses Double Chooz à l'aide de deux détecteurs, produisant sin² (2θ₁₃) = 0.111±0.018. / The Double Chooz experiment aims at accurately measuring the value of the leptonic mixing angle θ₁₃. To this intent, the experiment makes the most of two identical detectors -- filled with gadolinium-loaded liquid scintillator -- observing $antinue$'s released by the two 4.25GWth nuclear reactors of the French Chooz power plant. The so-called "far detector" -- located at an average distance of 1050m from the two nuclear cores -- has been taking data since April 2011. The "near detector" -- at an average distance of 400}m from the cores -- has monitored the reactor since December 2014. The θ₁₃ mixing parameter leads to an energy dependent disappearance of $antinue$'s as they propagate from the nuclear cores to the detection sites, which allows for a fit of the sin² 2θ₁₃ value. By reason of correlations between the detectors and an iso-flux site layout, the detection systematics and the $antinue$ flux uncertainty on the θ₁₃ measurement are dramatically suppressed. In consequence, the precision of the θ₁₃ measurement is dominated by the uncertainty on the backgrounds and the relative normalisation of the $antinue$-rates. The main background originates from the decay of βn-emitters -- generated by $mu$-spallation -- within the detector itself. The energy spectra of these cosmogenic isotopes have been simulated and complemented by a diligent error treatment. These predictions have been successfully compared to the corresponding data spectra, extracted by means of an active veto, whose performance has been studied at both sites. The rate of cosmogenic background remaining within the $antinue$ candidates has also been assessed. Addtionally, the normalisation of the $antinue$ rates, bound to the number of target protons within each detector, has been evaluated. All these works were part of the first Double Chooz multi-detector results, yielding sin² (2θ₁₃) = 0.111±0.018.

No description available.

The use of real-time continuous dynamics monitoring often indicates dynamic behaviour that was not anticipated by model-based studies. In such cases it can be difficult to locate the sources of problems using conventional tools. This thesis details the possibility of diagnosing the causes of problems related to oscillatory stability using measurement-based data such as active power and mode decay time constant, derived from system models. The aim of this work was to identify dynamics problems independently of an analytical dynamic model, which should prove useful in diagnosing and correcting dynamics problems. New statistical techniques were applied to both dynamic models and real systems which yielded information about the causes of the long decay time constants observed in these systems. Wavelet transforms in conjunction with General Linear Models (GLMs) were used to improve the statistical prediction of decay time constants derived from the system. Logic regression was introduced as a method of establishing important interactions of loadflow variables that contribute to poor damping. The methodology was used in a number of case studies including the 0.62Hz Icelandic model mode and a 0.48Hz mode from the real Australian system. The results presented herein confirm the feasibility of this approach to the oscillation source location problem, as combinations of loadflow variables can be identified and used to control mode damping. These ranked combinations could be used by a system operator to provide more comprehensive control of oscillations in comparison to current techniques.

Une revue générale est faite de la situation expérimentale concernant la mesure des masses, du mélange et des oscillations de neutrinos, ainsi que de la phénoménologie sous-jacente. Mes contributions à travers le programme expérimental du CERN, CHARM-II, CHORUS et OPERA, font l'objet d'un développement particulier. Le dernier chapitre tente de mettre en perspective le programme expérimental à moyen et long terme. The experimental situation concerning the measurements of neutrinos masses, mixing and oscillation is reviewed, as well as of the underlying phenomenology. A particular attention is given to the CERN experimental program to which I took or take part, CHARM-II, CHORUS and OPERA. In the last chapter, I try to put into perspective the medium and long term experimental programme.

The Sondheimer theory was tested by looking for oscillatory phenomena in a group of single crystals representing a range in dimensions from matchbox geometry to thin-film geometry. The single crystals were identical with respect to impurity content, strain, orientation, surface condition, and probe placement.

Neutrinos (v) are interesting for many reasons; they are the only fundamental fermions which are electrically neutral; their mass is orders of magnitude smaller than the lightest charged lepton, the electron; and their solely weak interactions make them an excellent probe of the weak nuclear force. However, one of the most interesting aspects of neutrinos is that, unlike their charged lepton partners, neutrino mass and flavor eigenstates are not the same. All leptons possess 'lepton flavor', a property which is conserved in neutrino interactions. However, because of the difference in the mass and weak eigenstates of neutrinos, a quantum-interference effect is seen in the time evolution of neutrinos. This results in energy and distance dependent oscillations of the neutrino's lepton flavor called 'neutrino oscillations'. The MINOS experiment (Main Injector Neutrino Oscillation Search) was designed to measure the neutrino oscillation parameters, [Delta]m²₃₂ and sin²(2[theta]₃₂). MINOS is composed of two detectors located on a 'beam' of v[subscript mu]s. The MINOS Near Detector is located at Fermilab, and the Far Detector is located at the Soudan Mine in Minnesota, 734 km after the Near Detector. The MINERvA experiment (Main Injector Neutrino Experiment for v - A) is a neutrino experiment placed directly in front of the MINOS Near Detector. MINERvA's goal is to make precision measurements of neutrino cross sections. This will help with uncertainties in oscillation measurements, such as MINOS' at low energy. Although lepton flavor is conserved in neutrino interactions, the final state lepton can be a charged lepton ('charged current' interactions) or a neutrino ('neutral current' interactions) of a particular flavor. The identification of charged current ν[subscript mu] interactions through the identification of a muon in the final state is a critical component to both neutrino oscillation and cross section measurements; neutral current events are a background to the oscillation signal because the properties of the incoming neutrino cannot be determined. Such identification is particularly difficult and important for low-energy neutrino events. In this thesis, we will discuss improvements to the MINOS charged current identification at low energies, studies to estimate the effect of the neutral current background on the measurement of the oscillation parameters, and the aspects of muon identification which are similar for the MINOS and MINERvA experiments. In 2010, the MINOS experiment released a measurement of the oscillation parameters based on 7.32x10²⁰POT. The results were [Delta]m²₃₂ = 2.32⁺⁰̇¹²[subscript 0.08] x 10³eV², and sin²(2[theta]₃₂) > 0.90(90%,C.L.). This is the best measurement of the oscillation parameter, [Delta]m²₃₂, and a competitive measurement of sin²(2[theta]₃₂). The improvements to the charged current event selection helped MINOS observe a complete oscillation in neutrino energy. / text

The Madden-Julian Oscillation (MJO) is the dominant mode of intraseasonal variability in the tropical atmosphere and provides global predictability on timescales that bridge the gap between weather and climate. The influence of the MJO on the ocean is explored with a combination of statistical analysis of observations using multivariate time series techniques, dynamical theory, and general circulation models with realistic forcing and bathymetry. The MJO is shown to have a significant and predictable influence on global sea level. Three main regions of influence are identified: (i) the equatorial Pacific and the west coast of the Americas, (ii) the Gulf of of Carpentaria, and (iii) the northeastern Indian Ocean. In the equatorial Pacific, equatorially trapped Kelvin waves are forced by MJO-related surface winds in the western Pacific and propagate eastward. These remotely forced waves then transform into coastal trapped waves that propagate poleward along the west coast of the Americas (consistent with previous work). By way of contrast, in the Gulf of Carpentaria it is shown that the connection with the MJO is due to local wind forcing through simple set-up of sea level. In the northeastern Indian Ocean, a complex sea level pattern involving equatorially trapped Kelvin waves, coastal trapped waves along Sumatra, Java and the Bay of Bengal, and reflected Rossby waves along 5.5$^\circ$N is shown to be caused by a combination of local and remote forcing by MJO-related surface winds. To examine the predictability of the MJO, and the stability of MJO variability on multidecadal time scales, the MJO index is reconstructed over the last century. The reconstructed index is verified by comparing it with independently observed environmental variables. Three predictability time scales are proposed and estimated from the MJO index. A simple forced damped harmonic oscillator model is used to explain the complex relationship amongst the predictability time scales and also gain insight into the predictability of the MJO.

The North Atlantic Oscillation (NAO) is the major mode of atmospheric winter variability over the North Atlantic. Its current state has long been described by the station‐based NAO Index. This index has been shown to represent winter temperature anomalies over Northern Europe well. Nonetheless, its positions of measurement are stationary and may not catch the moving NAO-pattern’s characteristics sufficiently well to best represent the Scandinavian winter temperature anomalies. A new index based on North Atlantic maximum and minimum sea level pressure (SLP) is introduced in this study (called NAOE Index). The points of NAOE Index are therefore moving over the North Atlantic SLP‐field and may better catch atmospheric processes affecting Scandinavian winter temperature anomalies. NAOE Index correlation with Scandinavian winter temperature anomalies is analyzed through NASA’s (National Aeronautics and Space Administration) MERRA‐data (Modern Era‐Retrospective analysis forResearch and Applications). This study shows that NAOE Index represents the Scandinavian winter temperature anomalies almost as well as NAO Index from observed values does. The indices are alsowell correlated with each other. The direct difference between maximum and minimum SLP is also analyzed with regard to the Scandinavian winter temperature anomalies. The SLP‐differences are class‐divided and their correlations to the class‐mean temperature anomaly are shown to be very high. This correlation issignificantly higher than the correlations of temperature and each index. Hence, the results from this study suggest that an index based on the direct extreme‐SLP‐difference is preferred for representing the NAO’s impact on Scandinavian winter temperature anomalies. This study gives additionally a comprehensive view of NAO. Studies concerning the NAO’s history of research, dynamics, temperature connections and secondary impacts are reviewed.

The goal of this paper is to explain the mathematics involved in modeling biochemical oscillations. We first discuss several important biochemical concepts fundamental to the construction of descriptive mathematical models. We review the basic theory of differential equations and stability analysis as it relates to two-variable models exhibiting oscillatory behavior. The importance of the Hopf Bifurcation will be discussed in detail for the central role it plays in limit cycle behavior and instability. Once we have exposed the necessary mathematical framework, we consider several specific models of biochemical oscillators in three or more variables. This will include a detailed analysis of Goodwin's equations and their modification first studied by Painter. Additionally, we consider the consequences of introducing both distributed and discrete time delay into Goodwin's model. We will show that the presence of distributed time lag modifies Goodwin's model in no significant way. The final section of the paper will discuss discrete time lag in the context of a minimal model of the circadian rhythm. In the main, this paper will address mathematical, as opposed to biochemical, issues. Nevertheless, the significance of the mathematics to the biochemistry will be considered throughout. / Master of Science

Collm (52°N, 15°E) midlatitude mesosphere/lower thermosphere (MLT) zonal winds are investigated with respect to a possible influence of the Southern Oscillation (SO). It is found that in winter the prevailing wind is positively correlated with the Southern Oscillation index (SOI), which qualitatively fits to the response of the low-latitude stratosphere on the SO. In summer, however, there is a negative correlation between MLT zonal winds and SOI. A possible mechanism, which includes slightly enhanced planetary wave propagation to the MLT in summers of low SOI is discussed. / Windmessungen aus Collm (52°N, 15°E) wurden hinsichtlich eines möglichen Einflusses der Southern Oscillation (SO) in ihnen untersucht. Es zeigt sich, dass im Winter der mittlere Zonalwind positiv mit dem \"Southern Oscillation Index\" SOI korreliert ist, was qualitativ mit der Reaktion der Stratosphäre auf ENSO übereinstimmt. Im Sommer findet sich jedoch ein negativer Zusammenhang zwischen hochatmosphärischem Zonalwind und SOI. Ein möglicher Mechanismus, der die Ausbreitung planetarer Wellen beinhaltet, wird diskutiert.