This PhD dissertation presents the measurement of the cross section of jet production in association with a Z boson in proton-proton collisions at the Large Hadron Collider in CERN, with a center-of-mass energy of 8 TeV in 2012 and of 13 TeV in 2015. The data used for this analysis were collected by the Compact Muon Solenoid (CMS) detector, with an integrated luminosity of 19.6 fb-1 in 2012 and of 2.25 fb-1 in 2015. The differential cross section is measured as a function of jet multiplicity, jet transverse momentum and rapidity, and the scalar sum of jet transverse momenta. The rapidity correlations between the Z boson and jets are also measured benefiting from the large statistics of data taken in 2012. All distributions of measured observables are obtained after correcting detector effects using unfolding approach, and the results of two leptonic decaying channels of Z boson are combined. Coming along with the systematic and statistical uncertainties, the measurement is compared to different theoretical predictions at different accuracy levels. The predictions are from MADGRAPH 5, SHERPA 2 (for 8 TeV analysis only), MADGRAPH_AMC@NLO, and fixed next-to-next-to-leading order (for 13 TeV analysis only). Thanks to the unprecedented high energy and the large statistics of data, precision measurement is accomplished in a physical phase space never reached before. This measurement provides precise systematics for different theoretical models. It also quantifies the improvement with higher order of perturbative quantum chromodynamics calculations on matrix elements relative to the leading order multi-leg approach. In particular to the rapidity correlation study, new matching schemes (FxFx and MEPS@NLO) for next-to-leading order matrix elements and parton shower show significant improvements with respect to the MLM matching scheme for leading order multi-leg matrix elements and parton shower. This measurement also gives precise background estimation for the measurements of many other processes in Standard Model like top quark production and gauge boson couplings, and for new physics searches such as Supersymmetry. In this thesis, the jet energy correction and calibration for the high level trigger system of CMS are also depicted. From 2012 to 2015, the Large Hadron Collider was upgraded, not only with the center-of-mass energy of the beams enlarged, but also with the instantaneous luminosity increased. The time distance between two particle bunches in a beam is reduced. As a result, the reconstructed momenta of the jets produced in each bunch crossing are significantly contaminated by multiple interactions. A dedicated technical approach has been developed for correcting the reconstructed jet momenta. The corrections have been calibrated and configured for the data taking in 2015 and 2016. / Cette thèse présente une mesure de la section efficace de production de jets associés à un boson Z dans les collisions proton-proton du Grand Collisionneur de Hadron (LHC) situé au CERN, avec des énergies dans le centre de masse de 8 TeV et 13 TeV, respectivement pour les années 2012 et 2015. Les données utilisées pour cette analyse ont été collectées par le détecteur Compact Muon Solenoid (CMS). Elles constituent des échantillons de luminosités intégrées de 19.6 fb⁻¹ et 2.25 fb⁻¹, respectivement pour 2012 et 2015. Nous mesurons la section efficace différentielle en fonction de la multiplicité de jets, de l’impulsion transverse et de la rapidité des jets, et en fonction de la somme scalaire des impulsions transverses des jets. La corrélation entre les rapidités du boson Z et des jets est aussi mesurée et bénéficie de la large statistique prise en 2012. Toutes les distributions d’observables mesurées sont obtenues après corrections pour les effets détecteurs et les résultats des canaux de désintégration muonique et électronique du boson Z sont combinés. Tenant compte des incertitudes statistiques et systématiques, les mesures sont comparées à différentes prédictions théoriques ayant différents niveaux de précision. Les prédictions sont obtenues de MADGRAPH 5, SHERPA 2 (pour l’analyse à 8 TeV uniquement), MADGRAPH_AMC@NLO, et un modèle fixé au NNLO (pour l’analyse à 13 TeV uniquement). Par ces mesures de précisions, et en particulier celle de la corrélation de rapidités, nous avons acquis une compréhension plus approfondie de la chromodynamique quantique dans son régime perturbatif. Grâce à la plus haute énergie jamais atteinte en laboratoire, et à la grande statistique disponible, nous avons sondé avec précision des endroits de l’espace des phases jusque là inaccessibles.Dans cette thèse, les corrections et la calibration de l’énergie des jets pour le haut niveau de sélection de CMS est également présentée. Durant la période de 2012 à 2015, le LHC a été amélioré, non seulement l’énergie dans le centre de masse a augmenté, mais la luminosité instantanée a aussi été amplifiée. L’écart temporelle entre deux paquets de particules dans les faisceaux du LHC a été réduite. L’une des conséquences est que l’impulsion reconstruite pour les jets produits lors d’un croisement de faisceau à une contribution significative venant des multiples interactions ayant lieux lors du croisement des paquets. Une approche technique dédiée a été développée pour corriger l'impulsion des jets. Les corrections obtenues ont été calibrées aux données prises en 2015 et 2016. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The current study is motivated by the relative lack of research on the contagion of deliberate self-harm, research on self-harm among adolescents in children's homes, as well as South African research on self-harm. In this study, I explore three aspects concerning deliberate self-harm in the South African context: The perceptions of adolescents in children's homes concerning the possible contagion of self-harm; the frequency, methods, duration and severity of self-harm among adolescents in children's homes; and lastly, the motivations of adolescent self-harm in children's homes. I make use of both quantitative measures, being the Deliberate Self-Harm Inventory (DSHI) developed by Gratz (2001) and the Functional Assessment of Self-Mutilation (FASM) developed by Lloyd (1997), and qualitative measures, being the logbooks completed by participants and three semi-structured interviews conducted, to address these questions. The current study uses both the functional approach to deliberate self-harm, that classifies self-harm according to the four functions that produce and maintain such behaviour, and the environmental model that emphasises the situational influences on the contagion of deliberate self-harm. The findings of the study indicate that 10 of the 12 adolescent participants have experienced either the acquisition or episodes of co-occurrence of self-harm through contagion, both outside the children's homes and within the children's homes. The contagion of self-harm is influenced by the desensitisation and growing prevalence of self-harm, frequent observations of self-harm, close personal relationships between individuals who selfharm, and the influence of the visual media. With regard to the findings of the DSHI, the methods most commonly employed for self-harm in the study include cutting, carving words into the skin, as well as the breaking of bones; the majority of the methods had been employed by the participants within the last year; and the emotions present immediately prior to the episode of self-harm include anger, depression, sadness, frustration, anxiety and disappointment. Findings from the FASM indicate that the motivation for the majority of the adolescent participants' self-harm is 'to stop bad feelings'. Furthermore, the findings of the study indicate that psychological intervention may be available to adolescents in several situations; that the personal histories of the adolescent participants include experiences of physical, emotional and sexual abuse, parental unavailability, the observation of parental alcoholism, as well as the experience of human trafficking; and suicide attempts have been made by the participants following instances of perceived ineffectiveness of self-harm. From the findings, it is evident that the contagion of self-harm is no longer a hypothetical phenomenon. Further implications of the study include the need for continued research on the methods reported by South African individuals who engage in self-harm that are not as prevalent in other research; and the influence of the study on the development and implementation of interventions to address self-harm in children's homes. Copyright / Dissertation (MA)--University of Pretoria, 2012. / Psychology / unrestricted

Le sujet principal de cette thèse porte sur la recherche d’un boson de Higgs additionnel de plus haute masse à travers sa désintégration en une paire de bosons de jauge Z (H → ZZ(*)) en utilisant les données enregistrées avec l’expérience ATLAS auprès du Grand Collisionneur de Hadrons (LHC). Quatre analyses distinctes sont présentées en fonction du mode de désintégration du boson Z soit une paire de leptons chargés (électrons ou muons), soit une paire de neutrinos soit une paire de quarks ; ces analyses sont appelés ZZ → 4l, 2l2ν, 2l2q et 2ν2q. L’étude utilise 20.3 fb⁻¹ de données de collisions proton-proton enregistrées au cours de la première phase du LHC (Run-1) à une énergie dans le centre de masse de 8 TeV. La stratégie de recherche segmente les données en supposant que les mécanismes de production de bosons de Higgs additionnel sont les mêmes que dans le Modèle Standard (SM), et modélise le signal avec une largeur qui est faible par rapport à la résolution de la masse invariante. La région de masse du boson de Higgs considéré s’étend de 140 GeV jusqu’à 1 TeV. Aucun nouveau boson de Higgs n’a été trouvé. La combinaison de résultats de quatre modes de désintégration donne des limites supérieures sur la section efficace σ de ce boson de Higgs additionnel (σ × H → ZZ(*)) qui s’étend de 359 fb à mH = 200 GeV à 11 fb à mH = 1TeV. Les résultats sont également interprétés dans le contexte des modèles au-delà du SM, à savoir les modèles à deux doublets. L’analyse H → ZZ(*) → 4l est également réalisée au cours de la deuxième phase du LHC (Run-2) en utilisant 3.2 fb⁻¹ de données de collisions de proton-proton enregistrées en 2015 à une énergie à une énergie dans le centre de masse de 13 TeV. Aucun excès significatif d’évènements sur la prédiction du MS n’est trouvé. Les limites supérieures sur la section efficace (σ × H → ZZ(*) → 4l) sont de 4.5 fb à mH = 200 GeV et 1 fb à mH = 1 TeV. La dernière partie de la thèse porte sur la caractérisation des détecteurs à scintillation d’ATLAS pour le déclenchement d’un biais minimal dans la région avant (le Minimum Bias Trigger Scintillators (MBTS)) en utilisant les rayons cosmiques. En raison de la dégradation des matériaux provoquée par des dommages dus à l’irradiation dans la première phase de fonctionnement du LHC, les MBTS devaient être remplacés lors de l’arrêt du LHC qui a eu lieu en 2014. Avant leur installation dans ATLAS, ces détecteurs ont été caractérisés en laboratoire en utilisant les rayons cosmiques. / The main subject of this thesis is the search for an additional heavy Higgs boson through its decay into a pair of Z bosons (H → ZZ(*)) using data recorded with the ATLAS experiment installed at the Large Hadron Collider (LHC). Four distinct analyses are presented, which are distinguished by the decay mode of the Z boson into either a pair of charged leptons (electrons or muons), into a pair of neutrinos or into a pair of quarks, denoted according to final-state, i.e. as 4l, 2l2ν, 2l2q and 2ν2q. The study is performed using 20.3 fb⁻¹ of proton-proton collision data recorded during the first phase of LHC operation (Run-1) at centre-of-mass energy of √s = 8 TeV. A search strategy is employed which segments the data according to the Higgs boson production mechanism, assuming that these are the same as in the Standard Model (SM). Furthermore, the signal is modelled with a width that is small compared to the experimental mass resolution. The Higgs boson mass range considered extends up to 1 TeV for all four decay modes and down to as low as 140 GeV, depending on the decay mode. No significant excess of events over the Standard Model prediction is found. A simultaneous fit to the four decay modes yields upper limits on the heavy Higgs boson production cross-section times H → ZZ branching ratio ranging from 359 fb at mH = 200 GeV to 11 fb at mH = 1 TeV for the gluon-fusion production mechanism, and from 214 fb at mH = 200 GeV to 13 fb at mH = 1 TeV for the vector-boson fusion production mechanism. The results from these four searches are also interpreted in the context of models beyond the SM, namely the Type-1 and Type-2 2 Higgs Doublet Model. The heavy Higgs boson search is also performed with the H → ZZ(*) → 4l decay mode alone using 3.2 fb⁻¹ of proton-proton collision data recorded during the second phase of LHC operation (Run-2) at an increased centre-of- mass energy of √s = 13 TeV. No significant excess of events over the Standard Model prediction is found. Upper limits are set on the heavy Higgs boson production cross-section times H → ZZ(*) → 4l branching ratio of 4.5 fb at mH = 200 GeV and 1 fb at mH = 1 TeV. Lastly, a project of a more technical character is presented. In this study, the scintillation detectors employed by ATLAS for triggering with minimal bias in the forward region, the Minimum Bias Trigger Scintillators (MBTS), are characterised. Due to material degradation caused by radiation damage in the early phases of LHC operation, the MBTS had to be replaced during the LHC shutdown taking place in 2014. Before installation in ATLAS, these detectors were characterised in appropriate laboratory facilities using cosmic radiation.

Les jets sont les signatures expérimentales des quarks et des gluons émergeant des diffusions dures produites lors des interactions hadroniques. La section efficace de production de jets se calcule dans la cadre de la ChromoDynamique Quantique perturbative (pCDQ), faisant des mesures de jets un test sévère des prédictions de la pCDQ. En collisions d'ions lourds ultrarelativistes, les jets constituent des sondes bien étalonnées du Plasma de Quarks et de Gluons (PQG). Dans des conditions extrêmes de température et de pression, les partons se déconfinent pour former une matière QCD en interaction forte. Les partons émis dans les collisions dures perdent de l'énergie à la traversée de ce milieu par perte d'énergie radiative et collisionnelle. Les propriétés des jets sont alors modifiées par rapport au vide, phénomène appelé étouffement des jets. Les propriétés de transport du PGQ peuvent être étudiées par la mesure de l'étouffement des jets.Les sections efficaces de production de jets chargés en collisions proton-proton (pp) aux énergies de 2.76 TeV et 7 TeV ont été mesurées par l'expérience ALICE puis comparées aux prédiction de la pCDQ à l'ordre dominant. En collisions Pb-Pb, l'intensité de la suppression des jets, inclusive et en fonction de la longueur de parcours dans le milieu, a été évaluée par la mesure des facteurs de modification nucléaire ($R_{mathrm{AA}}$) aux énergies de 2.76 TeV et 5.02 TeV. Le flot elliptique $v_{2}$, défini comme la distribution azitmutale par rapport au plan de réaction du deuxième ordre, qui est une grandeur sensible à la longueur de parcours des partons dans le milieu selon ou hors du plan de réaction, a été mesuré à l'énergie de 2.76 TeV. Cette mesure pour les collisions semi-centrales est en accord avec les prédictions théoriques. La réponse du milieu a été étudiée par l'intermédiaire des correlations jet-trace en fonction de la centralité de la collisionà l'énergie de 2.76 TeV. Les résultats obtenus suggérant une redistribution de l'énergie à grand angle par rapport à l'axe du jet. Ces résultats sont correctement décrits par des calculs phénoménologiques incluant l'évolution hydrodynamique du milieu.Dans cette thèse, deux aspects complémentaires de la mesure des jets à l'aide du détecteur ALICE ont été étudiés. D'une part, l'amélioration du système de déclenchement calorimétrique de l'expérience ALICE est présentée. Le Calorimètre Di-jet (DCal) a été installé pendant le premier arrêt long du LHC (LS1) afin d'étendre la couverture azimutale de l'existant Calorimètre ElectroMagnétique (EMCal) et Spectromètre à PHOtons (PHOS). Cette mise à jour a consisté à tenir compte de cette nouvelle configuration des détecteurs. Un nouveau micrologiciel de la carte électronique Summary Trigger Unit (STU) du sytème de déclenchement calorimétrique implementant un algorithme original combinant les informations des trois calorimètres a été développé. D'autre part, la mesure de la section efficace de production de jets chargés reconstruits avec différentes résolutions $R=0.2$, $0.3$, $0.4$ et $0.6$ en collisions pp à l'energie de 5.02 TeV est présentée. La comparaison de la section efficace mesurée avec les prédictions de la pCDQ à l'ordre sous-dominant (NLO) montre une bonne adéquation dans la région $10 < p_{mathrm{T},text{jet}}^{text{ch}} < 100 mathrm{GeV}/c$. La mesure du $v_{2}$ des jets chargés dans les collisions Pb-Pb semi-centrales (30-50%) à l'energie de 5.02 TeV est également exposée dans cette thèse. Les résultats obtenus ont été comparés à une simulation rapide basée sur le modèle de Glauber tenant compte de la dépendance de la suppression des jets selon leur longueur de parcours dans le milieu. Enfin, la mesure des corrélations entres jets chargés et hadrons dans les collisions Pb-Pb semi-centrales (30-50%) à l'energie de 5.02 TeV est présentée dans le but d'étudier la dépendance de la modification des jets en fonction de la géométrie de la collisions Pb-Pb. / Jets, defined as collimated sprays of high-momentum particles, are experimental signatures of hard-scattered quarks and gluons produced in hadronic interactions. The jet production cross section is calculable within perturbative Quantum ChromoDynamics (pQCD), and therefore jet measurements provide stringent tests of pQCD predictions. In relativistic heavy-ion collisions, jets are well calibrated probes of the Quark-Gluon Plasma (QGP). Under extreme conditions of temperature and/or pressure, partons are deconfined and form a strongly interacting QCD medium. The initial hard scattered partons lose energy while traversing this medium due to radiative and collisional energy loss. Consequently, jet properties get modified in comparison with the vacuum case, phenomenon named jet quenching. QGP transport properties can be studied by measuring jet quenching.The charged jet production cross sections in pp collisions at $sqrt{s} = 2.76 mathrm{TeV}$ and $sqrt{s} = 7 mathrm{TeV}$ were measured by the ALICE experiment and compared to Leading-Order (LO) pQCD predictions. In Pb-Pb collisions, the strength of jet suppression was quantitatively assessed at $sqrt{s_{mathrm{NN}}} = 2.76 mathrm{TeV}$ and $sqrt{s_{mathrm{NN}}} = 5.02 mathrm{TeV}$ via the measurement of the nuclear modification factors ($R_{mathrm{AA}}$). The strength of charged jet suppression was quantified as a function of in-medium parton path-length based on the measured $R_{mathrm{AA}}$. The jet elliptic flow $v_{2}$, defined as the jet azimuthal distribution relative to the $2^{nd}$ order event plane, which is sensitive to the difference of the in-medium parton path-length in-plane and out-of-plane, was measured at $sqrt{s_{mathrm{NN}}} = 2.76 mathrm{TeV}$. The measured jet $v_{2}$ in mid-central Pb-Pb collisions was consistent with model predictions. The medium response has been studied through jet-track correlations at $sqrt{s_{mathrm{NN}}} = 2.76 mathrm{TeV}$ as a function of centrality. The result suggested that the in-medium suppressed energy was re-distributed to large angles with respect to the jet axis. The phenomenon was described by a phenomenological calculation taking into account hydrodynamical evolution of the medium.In this thesis, two complementary aspects of jet measurements with the ALICE detector at the LHC were studied. First, the upgrade of the ALICE electromagnetic calorimeter trigger system is presented. The Di-jet Calorimeter (DCal) has been installed during LHC Long Shutdown 1 (LS1) to extend the azimuthal coverage of the existing ElectroMagnetic Calorimeter (EMCal) and PHOton Spectrometer (PHOS). The trigger system has been upgraded to account for this new detector configuration. The firmware for the Summary Trigger Unit (STU), which is the electronics of the trigger system, was upgraded to implement a brand new algorithm combining information from the calorimeters. Second, the measurement of the production cross section of charged jets reconstructed with cone resolution parameter $R=0.2$, $0.3$, $0.4$, and $0.6$ in pp collisions at $sqrt{s} = 5.02 mathrm{TeV}$ is outlined. A comparison of the production cross section to LO and Next-Leading-Order (NLO) pQCD predictions is shown. Good agreement of the production cross section with NLO pQCD calculations is found for $10 < p_{mathrm{T},text{jet}}^{text{ch}} < 100 mathrm{GeV}/c$. The measurement of charged jet $v_{2}$ in mid-central (30-50%) Pb-Pb collisions at $sqrt{s_{mathrm{NN}}} = 5.02 mathrm{TeV}$ is also presented. The results are compared with a toy-model Glauber simulation based on the measured path-length dependence of jet suppression. Finally, the measurement of charged jet-hadron correlations in mid-central (30-50%) Pb-Pb collisions at $sqrt{s_{mathrm{NN}}} = 5.02 mathrm{TeV}$ with respect to the $2^{nd}$ order event plane is also presented in order to study initial collision geometry dependence of jet modification in Pb-Pb collisions.

I takt med att CNC-fräsmaskiner blivit mer tillgängliga för allmänheten, växerbehovet av billiga alternativ till marknadsledande mätprobar (TTP). Generiska sensorer med öppen hårdvara finns tillgängliga till låga priser, men det är okäntom en sensor för under 100 kr kan användas som komponent i en mätprob, där noggrannhetskravet kan vara i storleksordningen mikrometer. Detta skulle isåfallinnebära att det finns en möjlighet att tillverka mätprobar till tillgängligare priser än dagens marknadsledande probar. Denna studie avsåg att undersöka ifall dessa sensorer var lämpade för ändamålet. Därför bedömdes ett antal Arduinokompatibla sensorer utifrån deras prestanda och lämplighet som komponent i en automatisk mätprob för arbetsstyckeslokalisering i CNC-fräsmaskiner. Sensorerna och principerna som undersöktes var: mikrobrytare, induktiva sensorer, ultraljudssensorer, IR-sensorer och kontinuitetssensorer. Sensorerna testades i en fräsmaskin och deras spridning estimerades genom att beräkna standardavvikelsen hos mätdatan. Efter en litteratursökning och intervjuer med KTHs akademiker samt den tänkta målgruppen för mätproben Stockholm Makerspace, bekräftades kravbilden på sensorn. Där belystes vikten av det låga priset på slutprodukten samt ett krav på att osäkerheten ska vara runt 0.05 mm. Mikrobrytaren konstaterades vara den lämpligaste sensorn. Detta beror på dess låga pris, oberoendet av materialet på arbetsstycket och den höga repeterbarheten. Repeterbarheten beräknades vara 5 μm med en konfidensintervall på 95%. / Since CNC-milling machines have become more accessible to the public, so has the demand for economical alternatives to the market-leading product, Trigger Touch Probes (TTP). Generic sensors with open hardware are now obtainable for a low price, but it is unknown if a sensor with a cost of under 100 SEK can be used as a component in a measuring instrument. Especially where the required accuracy lies in microns. If that is the case, it would be possible to manufacture TTP at more accessible prices than the current standard. This study aimed to answer whether the low cost sensors were suitable for this application. A number of Arduino compatible sensors were therefore evaluated in terms of performance and suitability as a component in an automated measurement probe for workpiece localization in CNC-machines. The sensors/ principles that were evaluated were: micro switches, inductive sensors, ultrasound sensors, IR-sensors, and continuity sensors. The sensors were tested in a milling machine and their statistical dispersion (scattering) were estimated by calculating the standard deviation of the data. After a literature study and interviews with academia from KTH and the intended customer, Stockholm Makerspace, the requirements on the probe were decided. The importance of the low cost of the final product were brought to attention and the requirement of a variance around 0.05 mm. The micro switch was evaluated to be the most suitable sensor due to the low price, high repeatability, and the fact that it was independent of the workpiece’s material. The repeatability was measured to be 0.0052 mm with a confidence interval of 95%.

Rainfed agriculture is inherently risky, with climate change expected to intensify its variability. In the West African Sahel, where agriculture is crucial not only for subsistence but for national and household incomes through cotton production, the need to safeguard farmers' livelihoods against risk is essential. Formal crop insurance providers in such contexts cannot easily rely on traditional models, where indemnifications are based on realized losses, and have instead proposed a stream of index-based insurance products which indemnify clients based on a predefined, and yet objective parameter (the index). One promising product for Burkinabe cotton farmers is, the Double-Trigger Index-Based Insurance (2TIC), whose two-tier triggering mechanism has the potential of reducing moral hazard and minimizing basis risk. This dissertation uses three essays to consider a farmer-centric approach to assessing the implications of this double trigger mechanism for index-based insurance. The first essay explores cotton farmers' judgments of fairness vis-à-vis the 2TIC indemnification system by using Principal Component Analysis (PCA) and Logistic Regression Analyses, and examines if and how these judgments affect decisions to subscribe. The second essay assesses the impact of 2TIC on farmers' cotton-derived net income by employing Coarsened Exact Matching (CEM). The third essay compares the actuarially fair premium of the 2TIC with the commercial premium paid by cotton farmers, by using statistical approaches. The study provides important evidence-based insights into how 2TIC can be improved and promoted by incorporating farmers' needs and perspectives.

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Dissertation submitted in partial compliance with the requirements for the Masters Degree in Technology: Chiropractic, Durban University of Technology, 2011. / Background: Myofascial pain is a disorder, characterized by the presence of trigger points (MTrP). It is recognised by unique features which include a tender point in a taut band of muscle, a local twitch response (LTR), a characteristic referred pain pattern, and the reproduction of the patient’s usual pain upon examination. A debate exists as to the precise diagnostic criteria used in identifying trigger points. This has hampered the standardized assessment and treatment of Myofascial Pain Syndrome and has led to contradictory findings being reported by various authors due to the lack of a reliable diagnostic tool. Objectives: The first objective was to determine the inter-examiner reliability of palpation of MTrPs in the trapezius and gluteus medius muscles. The second objective was to determine whether training and standardization in palpation techniques would improve inter-examiner reliability of palpation of MTrPs. Methods: This study was designed as a quantitative pre and post intervention interexaminer reliability study. Three examiners (one qualified Chiropractor, one senior chiropractic intern from the CDC and the researcher) were used to examine sixty patients (thirty symptomatic and thirty asymptomatic) for MTrPs. This study was conducted in two phases. During the myofascial examination of patients examiners were required to determine whether a MTrP was present or absent, differentiate whether the MTrP was active or latent and determine the presence or absence of the five characteristics of MTrP (tender point in a taut band of muscle, a local twitch response (LTR), a pain characteristic referred pain pattern, the reproduction of the patient’s usual pain and a jump sign) however, in phase one the researchers were blinded to the characteristics being investigated. Subsequent to phase one, examiners had to attend two, one hour discussion sessions to reduce individual variation in the application of palpation techniques. Results: Inter-examiner reliability was assessed using Fleiss Kappa statistic, percentage agreement and confidence intervals. The results show that three examiners are able to attain acceptable agreement in the palpation of MTrPs, since the features (described above) were shown to improve considerably in phase two after the training session in which standardization of techniques was emphasized. Conclusion: This study provides preliminary evidence that MTrP palpation is reliable and therefore, useful diagnostic tool in the identification of MTrPs and the diagnosis of Myofascial Pain Syndrome.